The Distribution and Ecology of the Freshwater

Home , Freshwater mollusc, Milda (gastropod)

THE DISTRIBUTION AND ECOLOGY OF THE FRESHWATER

MOLLUSCS OF NORTHERN BRITISH COLUMBIA

by Jacqueline S. Lee

B.Sc., Simon Fraser University, 1 98 1

THESIS SüBMITTED IN PARTIAL FULFILMENT

OF THE REQUIREMENTS FOR THE DEGREE OF

MASTER OF SCIENCE in

BIOLOGY

O Jacqueline S. Lee

THE UNIVERSI'W OF NORTHERN BRITISH COLUMBiA

Apil2ooo

AU ri@ reserved. This work may not be rcproduced in whole or in part, by photocopy or oula means, without the permission of the author. The author has granted a non- L'auteur a accordé une licence non exclusive licence ailowing the exclusive permettant la National Library of Canada to Bibliothèque nationaie du Canada de reproduce, loan, distri'bute or sel reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/nlm, de reproduction sur papier ou sur format 6lectronique.

The author retainw ownenhtp of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette &&se. thesis nor substantial extracts fkom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced *out the author's ou autrement reproduits sans son permission. autorisation. ABSTRACT Molluscs (i.e., snails, clams and mussels) are cornmon inhabitants of fteshwater habitats in norihan British Columbia (north of approximately 54W), yet little work has been done on these animals in this area. A large-sale study recorded 55 taxa of fnshwater molluscs in aorthem BC comprising 32 snail, 2 mussel and 21 clam taxa. Some of the factors that apped to affect the distribution of these molluscs were climate, dispersal barriers, glacial history and water chemistry.

Cornparisons of mollusc oommunity structure were made between historic and contempomy collections to monitor habitat change ova tirne. Diversity was generally found to be higher in contemporary collections, likely due to sampling bias, or incomplete processing and archiving of histonc collections. This emphasizes the need for stsndatdized collection and processing techniques in order to sustain consavation efforts.

A small-sale study was undden in the Lower Torpy River watershed to assess the effects of forest practices on fieshwata mollusc habitat. Lentic (standing water) habitats haà similar clam densities (Pisidium carertanum), water oonditions and mollusc community stnictun whaher nahiral or createù by forest pnctices (e.g., rosd building). The case was sirniiar for lotic

(fiowing water) habitats, alihough lotic and lentic habitats were signifimtly diffèrent in several ways. Lentic habitats had higher densities of clams, higher water ternpcrahirrs, lower dissolved oxygen levels end lower pH. Forest pradices in this watershed are intapnted to have increased the abundance of Pisidum carertanum by the aeation of additional habitats.

This work contributes to our ability to conserve the freshwater molluscs of northem British Columbia through better undentauding of their diversity, distribution and acology. TABLE OF CONTENTS

CEIAPTER 2 - DIVERSITY, DISTRIBUTION AND ECOLOGY OF FRESHWATER MOLLUSC IN NORTHERN BRITISH COLUMBIA: CLIMATIC, GEOGRAPHIC, POST-GLACIAL AND O'I'EER

ENVIRONMENTAL CONSIDERATIONSo oooowoeooeweoeoeoooooeooooooeeeooooooooooeooooooooo 12

CEAPTER 3 - COMPARISON OF CONTEMPORARY AND HlSTORIC COLLECTIONS OF FRESHWATER MOLLUSCS AS A MEANS OF ASSESSING ENVIRONMENTAL QUALIWo~~oo~e~o~eoooooeeeooooo~ooooooeoooeeooeo65 Conclusions ...... o.oo...ooo...... o.o...oo..o.....o...... o...... o.ooooo.....oo...o...... o 79 CHAPTER 4 - THE EFFECTS OF FOREST PRACTICES ON FRESHWATER MOLLUSC HABITAT: A CASE STUDY FROM THE TORPY RIVER WATERSEED IN EAST-CENTRAL BRITISH

COLUMBIA oooooooooooooaoooooeoooooooooooooooooooooooooooooooooooooooooooooooooooooooeoeoooaooooo 81

Study Area ...... m...... 83 Habitat Classification ...... 84 Sampling ...... 85

Lotic Habitats ...... e.e..e...... e...... e...... ~...... 87 Lentic Habitats ...... e...... ~...... 89 Ldc vs. Lentic Habitats ...... ++.+...... 90

Community Composition ..~.~~~.~~..~~~~~~~.~~~mm8~~~m~~s~ss~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+8Ss~~~~.~..m9 1 LIST OF TABLES

Table 1- 1. Systematic listing of freshwater mollusc found in northem British Columbia (according to Clarke 198 1)...... 2 Table 2- 1. Group numbers, group composition, table of significant t-tesb and figure numbers for range plots and Canonical Correspondence Analysis of the enviromnental. . data for the Grshwater molluscc collected at ecological sites in northern Bntrsh Columbia...... 2 1 Table 2-2. Record types, location map figure number, number of records, number of collections and dates of collection of hhwater molluscs fiom northern British Columbia...... 24 Table 23. Systematic list of the hhwater molluscs of northem British Columbia. 44*99 indicates taxa not found at ecological sites...... 25 Table 24. Number of freshwater mollusc collection sites in the drainages, major watersheds and biogeoclimatic zones in northem British Columbia...... 26 Table 2-5. Summary of altitude and climate information for the biogeoclimatic zones in northern British Columbia (Meidinger and Pojar 1991). BWBS = Boreal White and Black Spruce; CWH = Coastal Westem Hanlock; ESSF = Engelmann Spruce - Subalpine Fir. ICH = Interior Cedar - Hemlock; SWB = Spruce - Willow - Birch; SBS = Sub-Boreal Spruce...... 27 Table 26. Sample size, mean, staaderd cmw and range for the environmental variables mdat the ecological sites in northan British Columbia...... 34 Table 2-7. Significant difleretlces and degrees of Worn(df) in means of environmental variabks found witbin the groups or subgroups of fnshwater mollusc compared. Table 2-7 (cont.) Significant diffkmces and degrees of Worn (df) in means of environmental variables found within the pups or subgroups of fkshwater mollusc compand...... 36 Table 2-8. Sunrmary of the distribution and ecology of the bhwater molluscs from ecological sites in northem British Columbia...... 60 Table 2-9. Proportions of Wwater molluscs froin ecological sites in northem British Columbia as cornpad to the proportions offbhwater molluscs in Britain in relation to dissolved calcium content as described by Russell-Hunter (1978). Northern British Columbia hhwater molluscs d in this oomparison were those with n >2 plus the endemic species, Pljaela wrighti ...... 62 Table 3-1. Species lists for historical and contemponry collections made at sites in northem British Columbia "*" indicates co11ections that were made within the same water body but not at the same sites. Taxa found in both years are indicated in bold...... 69 Table 3-2. Cornparis of collection times (i.e. person-hours) and results of Sormson's Index of .Community Similarjty made been(1) contemporary collections and (2) hrstonc. collections...... 72 Table 3-3. Comparison of number of species and percentage of total number of species of the four fimctiod feeding groups of -water molluscs. Group 1 - Grazers (snails); Group 2 = Suspension fders (mussels and clams of the genera Sphoenum and Mwctrlium); Gmup 3 - Deposit Feeders (clams of the genera Sphaerium and Mwctllium); Group 4 =Infaunal fadas (clams of the genus Pisidurn)...... 74 Table 3-5. Species noted by Clarke (1972,1973a) as occurring at sites listed that are not confirmed by voucher specimens at the Canadian Mwum of Nature...... 78 Table 4-1. Average clam daisity and environmentai conditions (mean f SE [standard emr]) in al1 categories of habitat and riparian condition in the Lower Toqy Riva I watersbed ...... 88 Table 4-2. Culvert and upstream densities of Pisidium casertanum. "*" indicates deasity is significantly differait than culvert density at P < 0.05...... 88 Table 4-3. Results of ANOVA of density of Pisidium cusertunum at culvert pools and various combinations of upstream riparian conditions in the Lower Torpy River watemhexi...... 4...... -89 Table 4-4. Cornparison of lotic and lentic habitats (mean ISE) in the Lowa Torpy River Watershed and probability level of differences in means...... 90 Table 4-5. List of freshwata moiiuscs and their habitats in the Torpy River watershed...... 9 1 Table A-1. Site number, collection date, site description, NAD83 WTM coordinates and environmental. . variables for locations of Feshwater mollusc collection sites in northern British Columbia...... 107 Table A-2. Systematic listing of the fieshwater mollusc taxa of norihem British Columbia includuig figure number of distribution map in Appendix 1, maximum shell size (hmClarke 198 l), and occurrences out of 176 sites. Uncomrnon species were fond at Sl0 sites, common species were found at 1I to 50 sites, and very comrnon species were found at >50 sites...... 1 15 Figure 2- 1. Northern British Columbia fieshwater mollusc saidy area. "."indicates a sampling location (n = 176). Location of study area in British Columbia is evident on the map at the right...... 1 3 Figure 2-2. The biogeoclimatic zones of northem British Columbia. Those zones that apply to khwatamollusc sites are: BWBS = Boreal White and Black Spruce; CWH = Coastal Western Hemlock; ESSF = Engelmann Spruce - Subalpine Fir, ICH = interior Cedar Hdoclt; SWB = Spruce - Willow - Birch; and SBS = Sub-Boreal Spruce. "a" indicates a collection site...... 18 Figure 2-3. Major watersheds occdng in northern British Columbia. The Coastal, Fraser, Nus, Skema, Stikine, Taku and Yukon watmheds drain into the Pacific Ocean; the Liard, Mackenzie and Pace watmheûs drain into the Arctic Ocean...... 19 Figure 2-4. Ecological sites of collections of freshwater molluscs in nortbem British Columbia (Le., 'W 1" sites). "."indicates a collection site; n = 1 14...... 19 Figure 2-5. Non-ecological sites of collections of fieshwater molluscs in northern British Columbia (Le., 'Wû" sites). "." indicates collection sites; n = 41...... 20 Figure 2-6. Clarke's collections of freshwater molluscs in northem British Columbia (i.e., 'ZN" sites). 44*" indicates collection sites; a = 25...... 20 Figure 2-7. Miscellaneous collections of ûeshwater molluscs in northem British Columbia (i.e., "MN" sites). "*" indicates collection sites; n = I S...... 2 1 Figure 2-8. Dispersal routes of fmhwater fishes hmthe (a) Bering, (b) Pacifie and (c) Mississippi refbgia. niese patterns may ais0 be reflected in dispersal patterns of âsbwater molluscs. Amof refuge fiam the ice sheet is stippled. Dispersal routes are indicated by arrows. Dotteû lines delineaîe major drainage arras.(Fmm McPhail and Lindsry 1970.) ...... 29 Figure 2-9. Group 1: Range and means of enviromenta1 variables measiired for Family Valvatidae, Family Aaoloxidae and Family Ancylidac. 1 " indiates meaa. Minimum dcium concentration is indicated on plot (c)...... 37 Figure 2-10. Group 2: Range and mcans of environmental v&ables meadfor Family Lymnaeidae. " 1 " indicates mean. Minimum calcium concentration is indicated on plot (c)...... 38 Figure 2-1 1. Group 3: Range and mcrrns of environmental variables mdfor Famiiy Physidae. " 1 " indicates mem. Minimum calcium con~trationis indicated on plot (c)...... a....,....* Figure 2-12. Group 4: Range and means of envhnmaital variables mdfor Family Planorbidae. " 1 " indicates mean. Minimum calcium concentration is indicated on plot (c)...... 41 Figure 2-13. Group 5: Range and mcans of mvironmcntal va1iab1es measund for Family Marwtiferidae, Family Unionidae and Family Sphaeriidac; genus Sphaerium and genw MwcuIium. " 1 " indicates memi. Muiimum calcium concentration is indicated on plot (c)...... Figure 2-14. Group 6. Range and meaas of enviro~mentalvariables mdfor Family Sphaeriidae, genus Phidium. " 1 " indicates mean. Minimum calcium eoncmtration is indicated on plot (c)...... ~...... t....45 Figure 2-15. Canonical Correspondence Analysis of environmentai vaiables and taxa hm Gmup 1 (Family Valvatidae, FdyAcroloxidae and Famîly Ancyiidae) ...... 47 Figure 2-16. Canonical Correspondence Analysis of environmental variables and taxa hm Gmup 2 ( Family Lymnaeidae)...... 47 Figure 2- 17. Canonical Conespondence Anal ysis of enviromentai *variablesand taxa hm Gmup 3 (Family Physidae)...... 48 Figure 2-18. Caaonical Conespondence Andysis of environmental variables and taxa hm Group 4 (Famil y Plaaorbidae)...... 48 Figure 2-19. Canonical Conespondence Analysis of environmental variables and taxa hm Group 5 (Family Margaritiferidae, Family Unioniàae and genus Sphaerium and Musculium of Famiiy Sphadidae)...... 49 Figure 2-20. Canonical Conespondence Analysis of environmental variables and taxa hm Group 6 (genus Pisidium of Family Sphaeriidae)...... 49 Figure 3- 1. Regional Districts of British Columbia and intercensal human population estimates in 197 1 and 1996 for regional districts within northem British Columbia with percent change during this tirne period. (From British Columbia Statistics, Ministry of Finance and Corporate Relations, Vida, BCJ...... 66 Figure 3-2. Vertical icicle plot of the cluster dysisof the conternporary and historic collection sites of freshwatn molluscs of northern Bntish Columbia based on unweighted pair-group average of the spccies lists in Table 3- 1. bb*W indicates' samesite pairs that join directy...... 73 Figure 4-1. The Torpy River Watcrshed and its location in British Columbia...... 83 Figue 4-2. Density of Piddium casertanum dong the Lower Torpy Riva Road. 66*99 u~dicates*O ami of hi& dmsity (> 10,000 rn-'1...... 87 Figure 5- 1. (a) Numbn of specics pcr site at ecdogid sites in northem British Columbia (large-scalestudy) with pcrcentage of sites per species number and number of laitic and lotic sites pcr species nmôer. (b) Nmkof species per site in the Lower TorpyRivcr watcrshed and Pass Lake (smdl-sale study)with Fentage of sites per species nmber aiad nurnôcr of lentic and lotic sites per species nmber...... 96 Figures A4 to A-63. Distribution maps of taxa of khwater molluscs collected in mrthan British Columbia...... 117 - 234 Figure A-64. Sites where frtsbwater moIIuscs wae not collecteci...... 236 Figun AbS. The ecoprovinces of northern British Columbia4'~"indicates a coilection site... 238 CHAPTER 1 - INTRODUCTION AND OVERVlEW

Environmental change may be reflected in changes to water qualiîy. Freshwater molluscs may be excellent monitors of water quality because of their long life spans, feeding habits, ami persistent shells (Strayer 1999a). Freshwater molluscs are common components of inland aquatic ecosystems, yet little is known about this group in northern British Columbia (BC). In this study, biodiversity, distribution and physico-chernical conditions of the habitats of

âeshwater molluscs was examined on large and mal1 spatial scales. In addition, contemporary and histoncal collection records wcre compared to assess whether temporal changes in mollusc biodiversity may reflect environmental change.

Freshwater Molluscs

Phylum Mollusca oornpises invertebrate &als that are sofbbodied, non-segmeoted and have a made (an enveloping sheet of tissue that in most taxa secretes a ealcareous shell)

(Clarke 1981). In fkeshwater, molluscs occur in habitais ranging hmlarge lakes and rivers to mail, even tempomy, ponds (Pd1989). Fnshwata molluscs are primary consumers being * daceor suspaision feeders (Brown 1991, McMahon 199 1) and are prey items for ecologically and economicaüy important aquatic and tcmstnal predators (Pennak 1989). Freshwater molluscs are hmClass Gastn,poda and Cless Bivalvia, and comprise nine families b northern

BC (Table 1-1).

Class Gastrowdi

Gastmpods, or snails, have a muscular fmt on top of which sits a viscd mass commonly protected by a UIUvalvcd shell that is typicaily miled (Pechenik 1996). The fkhwata mails include the Subclass Piosobranchia (prosobranchs) and the Subclass Puimonata Table 1- 1. Systematic listing of f'reshwater mollusc found in nortbern British Columbia (according to Clarke 198 1).

Class Gasûopoda (Snails) Class Bivalvia (Mussels and Clams)

Subclass hsobranchia (Gilled mails) Order Eulamellibmchia Order Mesogastropoda Superfamily Unionacea Family Valvatidae Family Margaritifnidae Subclass Puhonata (Lunged snails) Family Unionidae Order Basomniotophora Superfamily Sphaeriacea Family Acroloxidae Family Sphaeriidae Family Lymnaeidae Family Physidae Family Planorbidae Family Ancylidae

Subclass Prosobranchia

in North America (which herein refers to that ana north of Mexico), thae are 49 genera

and -350 species of prosobranch saails (Burch 1989). These snails invaded river systems hm

estwies and retain the me gills of th& marine ancestors (Fuller 1974, McMahon 1983).

Prosobmchs have an operculum, which is a rigid or leathery disc that seals the shell aperture

when the snail's body is withdrawn into the shell (Haman and Berg 1971). Most piosobranchs

are dioecious (i.e., separate sexes) (Rupert and Bmes 1994).

hsobmchs tend have limited distniutions because they tolerate only limited va~iations

in environmental conditions (i.e., stcwtopic; Boss 1978) or have limitecl abiîities to disperse

(Hamian and Berg 1971). Prosobranchs tend to live in relatively deep water and so are less

likely to disperse passively (ir, dispersai due to the movement of other animak) than are

puhonates, which are often restricted to Wowwata by th& dependence on atmospheric air

(Boss 1978).

Of the tafamilies in the Subclass Rosobranchia in North America (Burcb 1989), only

members of the Famiiy Valvatidae have been found in northem BC. Fady Vaivrtidae

There are Il species in Family Valvatidae (valvatids) in North Anmica (Turgeon et al.

1998). These snails are generally les than eight mm in diameter with dextral coilhg (coiling

fiom left to right, as seen frnn the apex) (Burch 1989). Valvatids are unique among the

Subclass Prosobranchia in being monoecious (i. e., hermaphroditic; Head 1963), and unique

within the Order Mesogastropoda in possessing a bipectinate gill (Rupert and Bames 1994).

: This gill is feather-lile and extemal (Pennak 1989) and appears to allow valvatids to tolerate fine

substrates by pemitting good circulation for respiration without clogging the made cavity

(Yonge 1947).

Taxonomie issues within the Valvatidae

Clarke (198 1) ideniifid two species of valvatids hmwestern Canada, Yalvata sincero

sincera and Y. sincera helicoiàea. The raised axial striae (i.e. spiral ridges) used by Clarke

(1981, 1973b) as characteristic of Y. sincm sincera is interpreted by Burch (1989) as

characteristic of Y. lewisi lewisi. The fine axial striae used by Clarke (198 1) as characteristic of

K sincera helicoideo is interpreted by Burch (1989) as characteristic of Y. sincera sincero. This

study uses the identifying characteristics of Burch (1989) and Clarke's records have been reviseâ

accordingîy.

Subclass Pulmonata

There an 29 genera and -150 species of puimonate snds in North Amaica (Burch

1989). These snails do not have trw gills or an operculum (Rupert and Bames 1994).

Puimonates first invaded tenestriai habitats by losing th& gills and ddoping a richiy

vasdarized puim01181y cavity in the maatle useû to extract oxygm hmthe air (Brown 1991).

ThN subsequent invasion of Wwater can be mked in a series showing prognssively gceater

de- of re-adaptation to aquatic life (Russell-Hunter 1978). At one end of the series are some species of Lymnaeidae that breath air primarily. intermediate species (i.e., some species of

Lymnaeidae and the Physidae) use the pulmonary cavity to exchange oxygen with air or with water. At the other end of the series are the truly aquatic species that have developed pseudobranchs, which are gill-lobes not homologous with any part of the tnie gills of otha molluscs (McMahon 1983). These are the Planorbidae and the freshwater limpets (Acroloxidae and Ancylidae). Al1 pulrnonate snails are monoecious (Le., hennaphroditic; Brown 199 1).

Puhonates usually have broad physiological and ecological tolerances (euryoecic) allowing them to be excellent colonizers of a wide range of habitats @avis 1982). Reliance on atmospheric air restxicts many puhonates to shallow water where they can become afnxed to other animals and passively dispersed (Boss 1978). Most pst-glacially anerghg fnshwater habitats were probably colonized by molluscs arriving via passive dispasal. This concurs with the observation that there are far more pulrnonate than prosobranch snails in northem BC (Clarke

1981). Al1 five families of North American puhonates (Burch 1989) have beni found in northern BC (Table 1- 1).

Fa41JIY AcroIoxi&e

Members of the Family Acroloxidae are srna11 hpets that are tdy aquatic (Russell-

Hunter 1978). They occur mainly in Eurasia where thm are suspecies (Clarke 1970). The one species in North Amnica, Acroloms coloradensis, âisplays a nue and disjunct distribution and has ban considered for endangmd species designation in both Canada and the USA (Lee and

Ackennan 1999~).Acroloxidae have the apex of the shell tipped to the left so the aperture is considd to be on the right (Brown 1991). This is considered dextrai body organization and the pseuâobranch is on the right side of the animal's body (Burch 1989).

Fa- Lymnreidae

FdyLpaeidae (lymnaeids) is the most diverse pulmonate group in the northern US 1 and Canada (Brown 1991) with 57 species (Turgeon et al. 1998). Most lymnaeids are high I i; spired and have dextral shell coiluig although one western group has limpet-shaped shdls (Burch 1 1989). The tentacles of lymnaeids are broad, flat and trianguiar rather than the long, th, filamentous tentacles of other freshwater pulmonates (Burch 1989).

Lymnaeids respire Ma their pulmonary cavity and primarily rely on aerial respiration

(Burch 1989) making them somewhat amphibious (Brown et al. 1998). They are considered the

a most primitive of the freshwater puhonate families, as they are unspecialized stnicturally for

aquatic life (Russell-Hunter 1978).

Famüy Physidie

The 43 species of the Family Physidae (physids) in North America purgeon et (il. 1998)

are the most abundant and widespnad of the frcshwater gastropods (Burch 1989). Physids are high spid and have sinistral shell coüing (Le., coihg from right to le& as seen âom the apex).

Some physiâs rely on aerial respiration and are sommhat amphiiious (Brown et al. 1998)

whereas others fil1 the pulmorq cavity with watcr and use it as a derived giil (Russell-Hunter

1978). In these nspects, physids are considereâ more advanced in their adaptation to aquatic life

than the lymnaeids.

Taxononiic issues within the Pliyside

Diffaent authors use différent generic names to desai species within the Family

Physidae. nie exception is the genus Aploui. wbich ha9 a distinct moiphology. Prior to Te's

(1978) mrision of the Family Physidae, most authors placed al1 otha North American physids in

the genus Physu (e.g., Clarke 1973b' 1981). Te's (1978) study assigned the North American

physids into the gcnera Aplex~,Physa, and Physella based on detailed anatomical stuâies. While

this classification is useâ by Burch (1989) and by Turgeon et al. (1998)' Wu (1989) and Wu and

Beetle (1995) d mother system. Wu and CU-worlasassign all North Amnican physids (other than Aplexu) to the genus Physa, which was in tum subdivided into thne subgenera based

on the type of the terminal male genitalia (Physa, Physella or Physodon). For example, the

species referred to as Physa gyn'nu by Clarke (1973b, 1981) is referred to as Physella gyrina by

Burch (1 989) and Turgeon et al. (1998), and as Physa (Physella) gyrïna by Wu (1989) and Wu

and Beetle (1995). Therefore, the genaic name used depends on the date of the publication

andior on the taxonomie preference of the author. The nomenclature used in this study is

' according to Turgeon et al. (1998). which follows Te's (1978) classification.

Collections made in the course of this study were identified to species for the genm

Apleui and Physa, but not for the genus Physella. nie exception was Physella wghti, which

was identified by its presence in its type locality, Liard Riva Hotsprings. Identification of other

Physella species required anatomical expertise that was not available. ûther members of the

genus Physella that are identified to species in this study are hm collections held at the

Canadian Museum of Nature.

Family Planarbiàae

Thm are 48 species in Fatnily Plawibidae (planorbids) in North America (Turgeon et al.

1998). With a few exceptions, planorbid shells are discoidal (i.e., coiled in one plane) and al1 are

sinistral (Burch 1989). However, many species appear to be dextral because the shell tips to the

lefi side, hence they are termeû "pseuâodextral" or "ulûasinistral"(Burch 1989).

Planorbid snails are truiy aquatic having a pseudobranch on the Iefi side of the body

(Burch 1989, Brown et ai. 1998). The respiratory pigment of haemoglobin in this family gives

the animals a teddish appearance (McMahon 1983).

FadyAncylicht

There are 13 @es in Family Ancylidae (aucylids) in North Am& (Turgeon et al.

1998). These aply aquatic hhwater ümpets have snali, cap-shaped &eus with the apex tipped to the right so that the aperture is considd to be on the left (Brown 1991). This is considered sinistral body organization and the pseudobranch is on the lefi side of the body (Burch 1989).

Class Bivalvia

The hhwater bivalves in northem BC are hm three families; Margaritifendae and

Unionidae, the freshwater mussels, and Sphaeriidae, the freshwater clams. Al1 native Cadian fieshwater bivalves are in the Onfer Eularnellibranchia This order is characterized by a hinge containing a few teeth of divme shapes and sizes, two large adductor muscles of about the same size, one anterior and one posterior, a partly closed made with well-developed siphons, and leaf-like gills within the mantle cavity (Clarke 198 1).

Famiües Margaritiferidae and Fa- Unkniàae - Fmhwater Mussels Freshwater mussels may have ktwolveû in rhe Mississippi drainage basin where the greatest diversity of species is foud (Pm& 1989). Thae are five species of Margaritifendae and 299 species of Unionidae in North Amaica (Turgeon et al. 1998). The Marghtiferidae and

Unionidae are separated by sofi tissue characteristics with the main differentiating fature king the lack of siphons in the Mmgaritiftridae (Bmh 197%).

Al1 native North Amcrican Mwater mussels are associated with benthic sediments where they are suspaision fders. Dispersal occurs in the fonn of unique, glochidiai lwa that become temporary and obligatory parasites on fil (Pd1989). This reproductive methcd limits passive dispersai and is likely to have resulted in the evolution of the relatively large number of gewa and species (BurLy 1983).

In the Pacific drainage of No& America, the musse1 fauna consists of genera A?rahnta,

Gonidea and Matgaritifm (Pcnnak 1989). The range of A. knnerlyi and M. folcata includes parts of northern BC, whereas G. mguIattz end utha qxcies of Anodontn accia only in oouthem BC. 1 j Famiïy Sphaeriidae - Fmhwater Ciams

I The family Sphaeriidae (sphaeriids) has evolved dong two major lines. The first, genm

Sphaerium and M1csculium, are associated with benthic surfaces (McMahon 1991) and the

second, geaus Pisidium, lives within organically rich sadiments (Lopez and Holopainen 1987).

Sphaeriids are able to disperse passively by clamping on to the lhbs of aquatic insects,

: the fathers of water fowl, or even the limbs of salamanders, and some can survive ingestion and regurgitation by duch (see review in McMahoa 199 1).

Genus Sphaen'um and Geniis Musculium

There are eight species in the genus Sphceri~mand four species in the genus Mtlsculium

in North America (Turgeon et aL 1998). Both gniera have branchial and anal siphons but

Sphaerium have these siphons fused oniy at their bases, whereas Musctllium have than joined

for most of their length. Both genera have the posterior end of the shell longer dian the anterior

adbut the shell of M1(sculium diffas fiom that of Sphceriurn in having raid umbonal (mbo =

the apex of a valve) caps (Bmh 1975a).

Sphomum and Musculium @es can use their siphons in suspension or deposit feeding,

or can w their ciliated foot epithelim to collect food in a method cdled pedd deposit fealing

(Hombach et al. 1984, Way 1989, McMahon 199 1).

Genus Ridiüum

Ptsidium species are the most cosmopolitan, abundant and widely disbrauted family of

firshwater bivalves (Burky 1983). There are 26 species of Pisidum desmi hm North

America (Turgeon et al. 1998) plus at least one undescribed species (Fmand Johannes 1995).

Pisidium species have the anal siphon present but the branchial siphon is absent or represented

by a slit in the mantle, and the sheli hm a longer posterior then anterior end (Burch 1975a).

Pkidium species live in horizontal bmwswithin organically nch sediments where they filter feed on interstitial bactnia (Meier-Brook 1969, Lopez and Holopainen 1987). Size may be

- a constraint of this mode of feeding and may expiain the chcteristically srnall shell size (1.7 to

12 mm long) of many Pisidiun species (LOF and Holopainen 1987).

Northem British Columbia Study

Northern BC, which in this shidy is defined as the region north of approximately 54W

latitude, har abundant ûeshwata habitats. These habitats are relatively young geologically and

are inhabited by a variety of organisms including freshwater molluscs. Shidies of tieshwater

molluscs were undertaken to document th& diversity, distribution and ccology.

In general, the euryoecic nature of many pulmonate mails and sphaeriid clams has

resulted in their widespread distribution, whereas the stenotopic nature of many prosobranch

snails and reproductive characteristics of mussels has restricted theh distributions. Witb theu

range, the habitat requirements of inâividual taxa may nstnct their distriaution to certain water

bodies. Water conditions, maao-vegetation, and substraîum are associated with hhwata snail

fama (Hamm 1972,Okland 1983). Trophic condition also seems to be of partidm importance

in determining the presence of certain molluscs (Green 197 1, Clarlre 19794 Clarke 1979b, Costil ,

and Clement 19%, Dillon 1997). Lodge et al. (1987) and Brown et al. (1998) noted the

importance of distuhance, cornpetition, food selection, predation ami physiochemicd ngimes in

stnicturing fkshwater snail assemblages. Howem, Haag and Wamn (1998) found that the

pattern of freshwater musse1 assemblages was bctter explsined by the pattern of fish

commUHities rather than by ecological factors.

Accordhg to Lodge et al. (1987), biogeographic and evolutionary hisîory determines the

ptential pool of snaii c010aizers, whüe abiotic tàctors such as clhate, chanistry and substrate,

act as a filter for colonists. It is liythat the same can be said for freshwater clams. while

musse1 distribution is linked to thet of th& fish hosts. These factors act on differat spatial

9 j scals and rary in imprtaace in difiermi wita bodies. Thus, it is likely that many processes I i may explain the heterogeneity of community stnictuns in freshwater molluscs. The difficult 1

1 1 issue will be to determine the relative importance of each of them for particular taxa.

Chapter 2 presents the results of a largescale spatial study based on new and existing i collections, which were assembled to determine the diversity, distribution and ecology of

fieshwater molluscs in northem BC. The distribution of mollwcs taxa were examined hmthe

perspective of large-scale climatic diffetences, location of potentiai geographic barriers,

hypothesized pst-glacial dispersion routes, and rneasurements of selected environmental

variables. Analyses of some of the putative factors that may be responsible for the current

pattans of distribution are presented.

It is nasonable to suggest that incmsed population and resorrrte use in northern BC may

have impact4 quatic ccosystems in a manner that may be reflecteâ in the community structure

of molluscs. Histoncal infoxmation on the fr'eshwater molluscs of northem BC was available

hm collections made during the sununets of 1972 and 1973 by Clarke (Lee and Ackemum

1999a). In Chapta 3, these data are compareci to contemporary data obsdat the same sites.

Forest practices are causing lmdscape alterations in northem BC that have Iikely affectecl

quatic habitats through increased sediment deposition and changes in water tempaahm

regimes. These changes are Iikcly to affar âeshwater molluscs. While severai authors nave

amibuteci changes in fieshwater mussel comminiity structure to deforestation and loss of riparien

vegetation (News 1992, William et al. 1993, Morris and Corkum 1996, Bogan 1998, Box and

Mossa 1999), similar studies of the effm of such changes on Wwater saails or clams do not

exist. Chapta 4 pfesents the dtsof a smali-scale spatiai snidy to assess the impact of forest

practices on âeshwater mail and dam habitat in a northem bord watershed. Both qmtitative

and qualitative assessments of freshwater habitats wae made to track anthropogenic impacts

within this watershed. The findings suggest that anthpogenic activities may k affecting the

10 abundance of certain taxa of fieshwater mollusc within this watershed.

Chapter 5 presents a ~~t~l~llaryof the findings hmthe perspective of large and mal1 spatial scales. This thesis contributes to our understanding of the historical, geographical, ecological and anthtopogenic processes that affect the distribution, ecology and community structure of frtshwater moliuscs in northem BC. This provides a scientific basis upon which fwther research can be conducted to understand, conserve and protect our freshwater organisas and ecosystems. CHAPTER 2 - DIVERSITY' DISTRIBUTION AND ECOLOGY OF FRESHWATER MOLLUSC IN NORTHERN BRITISH COLUMBIA: CLIMATIC, GEOGRAPHIC, POSTIGLACIAL AND OTHER ENVIRONMENTAL CONSIDERATIONS.

Introduction

This study examines the diversity, distribution and edogy of freshwater molluscs in

, northernBritish Columbia (BC). This relatively large ana (-550,000 km2;Figure 2- 1) contains:

(1) regions with mem mual temperature ranghg hm-2.9 to 8.7OC; (2) major drainages basins

that lead into the Pacific and Arctic oceaus; (3) is mssed by the Rocky Mountains in the

northeast; and (4) has been ice fne since the retreat of glaciers about 10,000 years ago. This

heterogeneous landscape contains abundant water bodies that are likely to have diffaait

histories and ecological characteristics.

New and existing field data wen used to examine distribution of fieshwater mollusc taxa

in northern BC. The following factors were examined in an effort to identifi the likely causes of

the pment distributions of molluscs: (1) climatic effects - based on biogeoclimatic zones

(Meidinger and Pojar 1991), as sow climatic conditions may excluâe molluscs; (2) pst-glacial

history, which influenced how molluscs were able to disperse in nortbem BC; (3) dispetsal

mechenisms, as some molluscs may be unahle to cross geogmphic barriers; and (4) alien species

(i.e., those dedoutside th& original ranges by human activities), which can affect the

distribution of fkshwater molluscs (Strayer 1999b).

As bhwater molluscs rcspond to the characteristics of the water in which they live

(Brown 1991, McMahon 1991), selected physioo~chemicaiwata conditions were mdto

record possible ecological requiremcnts of the moliusc taxa of northem BC.

Thtoughout North America, many f'reshwater moiiuscs are impaiied due to habitat

alteration and the introduction of exotic spacies (Brown et al. 1998, Strayer 1999b).

Consavation and rehabilitation efforts cmonly be based on existing information. The purpose 12 i of this study is record some of the historical, geographic and ecological factors ihat may be

responsible for the observed patterns of distribution of khwater molluscs so that this '1 information can act as a basis for the protection and consavation of the freshwater molluscs of northem BC.

Materials and Methods Study Area and Site Selection The study area (Figun 2-1) incorporated BC north of appwkimately 54W latitude with

the exception of the Queen Charlotte Islands and the extreme norihwest of the province, whicb

were not acccssed during the course of the study. As the only access road between the west and

east of the far noah of BC requires incursion into the Yukon at two points, some collections were

also made in the Yukon. Site selection was maâe in an attempt to maximize biodivmity

information while including as much of northcrn BC as was ailowed by acassibility, tirne and

Figure 2-1. Northcnr British Columbia âeshwata mollusc study area. "."iadicates a samphg location (n = 176). Location of study area in British Columbia is evident on the map at the right. Field Sampling Most of the area was sarnpled August 6 - 26, 1997 with othei collection dates noted in

Table A-1 (Appendix 1). Most sarnpling was done fiom road-accessible shore areas but if this did not appear to provide the best habitat to ensure adequate represent~tionof the mollusc fa-

.a canoe was used to access other areas. Molluscs wae generally colleçted after mthg the water wearing chest-waâers. An 18 cm diameter stainless steel mesh net (nominal pore size of

-1 .S mm) attached to a 1.5 m bmm handle with hose clamps was used to swm vegetation for snails and to dig into sofi Sediments for the collection of mussels, clams and sediment mg snails to the maximum depth allowed by the waders (-1.5 m). Aqdc vegehtio& such as lily pads (Nuphar sp.), was also examined for rnoiîuscs and submerged rock and Wood, when present, were lied off the bottom for examination to the maximum depth possible (-0.6 m). In some instances when the came was used, sampling was attempted in d- water (maximm 5 m depth) with a PONAR grab (Wildco, Sa-w, MI, USA) with a 15.2 cm x 15.2 cm sampling am (0.23 1 m2).

All molluscs collected wne kept in water and put into an Wated container for later proccssing. SpecUnens were relaxeci kfon prescrvation by spnnkling the of the wata in the coUection container with granulated menthol (Brown 1991). The addition of a drop of propylene phenoxetol was made to help relax difficult taxa (McMahon 1991). Jars conteining specimens and relaxants were !ef? undisturbed ovemight. Wata was then qlaced with a solution of 5% foddehyde in which specimens were lefi for 3-7 dap to fix h~. were then moveû to a long-term pfcsc~ativeof 7û?! ethan01 coot-g 34% @YC- by volume to help keep tissues pliable (McMahon 1991). Al1 spimens were later soried by taxa using criteria presented in Buich (1975% 1975b,

l989), Clarke (1 973b, 198 1) and Herciagton (1 962, 1965). Voucher specimens were established

in a reference collections at the University of Northem BC and at the Royal British Columbia Museum.

Water quaiity measunments were made once at each site, usually âom an area close to

shore and witbin the top 10 to 15 cm of water. The meamrements made were: (1) water

a temperature (OC) with an alcohol themorneter; (2) dissolved oxygm (% saturation), and (3)

conductivity (microSiemens - pS) with a Corning Checkmate Modular Maer System (Corning hc.,Cornin& NY, USA) and; (4) pH with a Canlab (Mississauga, ON, Canada) portable digitai

pH meter Mode1 607.

Rodhe (1949) found that the average proportions of the major dissolved mineral

collstituaits of fnshwater wmabout the same regardlesci of the absolute conductivity. Thus, the

calcium concentration of freshwater cau be approximated from the conductivity reading. The

data presented in Table 2 of Rodhe (1949) was used CO produce a regession equation to convert

conductivity measures into dissolved calcium levels (mg).The quation for this conversion is:

mg Calciumllitre = (-1.3 f 0a2) + (0.1491 f 0.0008) x aondudivity, n = 20,3 = 0.9995, and p 4.00 1.

Rhode (1949) badhis stuâies on measureanents taken hmlakes. It was assumed that

the relationship ktween conductivity and calcium held tme in d systems ampleda

The NAD83 (No* Americen Dam 1983) UTM (Universai Transverse Mercator)

coordinates for each field site were read with a TNnble Geo-Explorer (TNmble Navigation,

Sunnyvale, CA, USA). Rint and slide photographs were taken of each site with the compas

dirraion of the angle of Mew noteû.

Some contempotary coUcctions of âeshwater moiiuscs were also made fbm sites where

no ecological, WTM or photopaphic information was ncorded. : Data Processing Contempomy collections of freshwater molluscs were classifiai as two types: (1)

ecological sites, where samples were collected and enviromenta1 variables, NAD83 UTM and

photographs were recorded. These sites were assigned record numbers preceded with 'Nl"and;

(2) non-ecological sites, where samples were collected but only the locations were recorded.

These sites were assigned record numbers preceded with 'WN.

A visit to the Canadian Museum of Nature (CMN)was made in December 1997 to obtain

information on their collections of BC fieshwater molluscs. The collections made by Clarke in

northem BC during 1972 and 1973 wmcombined with his field notes (Clarke 1972, 1973a) into

site summaries with record numbers preceded by TN" (Clarke North). Al1 other histonc

collections hmnorthern BC were made between 1875 and 1974 and these site summaries were

assigned record numbers preceded by "MIS" (Miscellaneous North).

Royal British Columbia Musami (RBCM)holdiags provided no additional information.

However, RBCM staff pmvided an unpublished nport by a fkshwater malacologist, h.Dwight

D. Taylor (Taylor 1993). This report included information on collections made in the Athara

of northem BC and these have been hcludeâ with other records preceded by "MEP.

For al1 sites without UTM coordinates, the site descriptions wmused to find the location

on 1:Sûûûû demaps hm which the NAD27 UTM coordinate was ncorded. These

ooordinates were converteâ to NAD83 using ArJuifo software (ESRI hcorporateâ, Redlands,

CA, USA).

Information on ail of these four site types (i.e., N1, NO, CN and MN) was compiled into

Lee and Ackerman (1999a) resuiting in information on 195 sites. For mapping purposes,

oollection sites that coincided were combined resulting in 176 sites hm the original 195

records.

The NAD83 coordinates and a taxa list for each of the 176 sites was supplied to the 16 Geographic Information Services technical staff at the Conservation Data Centre, a unit of the

Resource and hventory Branch of the MUiistry of Environment in Victoria, BC. With their instxuction and assistance, a map of al1 the sites was producd (Figure 2-1) and overlain with the theme layers of biogeoclimatic zone (Figure 2-21, watershed (Figure 2-3), and ecopmvince

(Figure A45 in Appendix I) and in order to assip these attributes to each site. Distribution maps were produced for each type of record classification (NI- Figure 2-4; NO - Figure 2-5, CN

- Figun 26; and MN - Figure 2-7), for each of the taxa recorded hmnorthan BC (Figures A-

1 - A63 in Appendix I) and for the sites where no molluscs were coliected (Figure A-64).

Taxa wne considered uncornmon if they were recorded hmS10 sites, common if

recorded hm1 1 to 50 sites, and very common if recorded hm>50 sites (Table 2-8).

Environmental Data Analysis T-tests, range plots and Canonical Comspondence Anaiysis (CCA) were usd to

examine environmentai data. As CCA nquires at least as many taxa as environmental variables,

fdies represented by fewa than four taxa were combhed with other families or genera This

dtedin six groups ranghg in size hmfour to 14 taxa (Table 2-1). Group 1 comprised

gastropod families with one or two taxa (Valvatidae, Acroloxidae and Ancylidae). Group 2, 3

and 4 comprised Families Lymnacidae, Physidae and Planorbidae, respectively. Group 5

comprised the two families of mussels plus the genaa Miculium and Sphaerium of the Family

Sphaeriidae, and Group 6 comprised the gmus Pisidum of the Fady Sphaedae. It was

appropriate to divide the family Sphaeriidae in this matter based on hctioaal diffaaues.

Species of the genera Spherium and Murculium are dace fders (Way 1989), whereas

species of the genus Pisidium are interstitial feeders (Lope2 and Holopainen 1987). Rdtsof

these analyses are discusseû by famiy for gasüopods and mussels, and by genus for sphaeriids. Figure 2-2. The biogeuclimatic zones of northern British Columbia. Those zones that apply to âeshwata moUusc sites are: BWBS = BodWhite and Black Spce; CWH = Coastal Western Hemiock; ESSF = Engelmann Sp~ce- Subaipine Fir, ICH = Intexior Ce& Hemlock; SWB = Spruce - Willow - Bircb; and SBS = Sub-Boreal Spa."a" indicates a collection site.

Figure 2-3. Major watersheds occuning in norihem British Columbia The Coastal, Fraser, Nass, Skeem, Stikine, Thand Yukon watersheds drain into the Pacific ûcean; the Liard, Mackenzie and Peace watersheds drain into the Arctic Ocean.

Figure 2-4. Ecologid sites of collections of fnshwater molluscs in northem British Columbia (i.a, "NI" sites). "a" indicates a collection site; n = 114. Figure 2-5. Non-ecological sites ofcollectioll~of âeshwater moliuscs in noahan British Columbia (i.e., 4'Nû"sites). "."hdicates collection sites; n = 41.

Figure 2-6. Clarke's oollections of Wwater molluscs in northem British Columbia (i.e., "CN" sites). "a" indicaies collection sites; n = 25. Figure 2-7. Miscellaneous collections of fnshwater molluscs in northem British Columbia (i.e., "MN" sites). "0" indicates collection sites; n = 15.

Table 2-1. hpnumbers, group composition, table of sigeificant t-tests and figure numbers for mge plots and Cenonical Comspondence Analysis of the environmental data for the kshwata molluscs collected at ecologid sites in northern British Columbia. Croup Croup Composition Sîgnificant Range Plot Canonicd No. t-tub Corrapondtnce Andysia Family Valvatidae (2 taxa) Table 2-7 Figure 2-9 Figure 2-15 Family Acroloxidae (1 taxa) Family hcylidae (1 taxa) Fpmily Lymuacidae (9 taxa, Table 2-7 Figure 2-10 Figun 2-16 1 generic iddation) Family Physidac (3 tiuca, Table 2-7 Figure 2-1 L Figure 2-17 1 gencric identification) Fardy Phorbidat (1 l taxa) Table 2-7 Figure242 Figurc2-18 Family MargatitifCndac (1 taxa) Table 2-7 Figure 2-1 3 Fi- 2-19 Family Unionidae (1 taxa) FdySphaeriidw; Genus Sgihrerium (3 taxa) &nus Miculium (2 taxa) ~amilySphaaiïdae; Table 2-7 Figure 2-14 1 Fi- 2-20 Genus Pisidiurn (1 3 taxa, 1 pcric idcnsification) T-tests

A t-test (Statistica 5.1, StatSoft, Inc. 1997) was used to evaluate the diffaence in mean between each environmental variable measured for each taxon in familia or genera examineci.

A probability level (p-value) of 0.05 or less was accepted as indication that the two taxa being compared had significantly different means of the particular variable.

Range Plots

Plots of the range of each mvironmental variable measued for each taon were produced for the six groups (Figures 2-9 to 2-14). The value measured for taxa found at single sites were indicated with a dot (9.The mean for each variable was marked with a vatical line and the plots for conductivity inciudeû the minimum calcium concentration caiculated.

Cononical Correspondence A~naljsis

Canonid Comspondence Analysis (CCA), which examines the relationship of taxa and environmental variables, was undertaken using CANOCO version 4.0 software (Microcornputer

Power, Itheca, N'Y, USA) on the six groups (Figures 2-15 to 2-20). Temperature and pH mmhm al1 the ecological sites displaycd noddistributions (Shapiro-Wilks W test; W =

0.9854, p < 0.7909 aad W = 0.9774, p < 0.3720 tespectively). Dissolvcd oxygen and conductivity did not display nomial distriions (Shapiro-Wib W test; W = 0.9547, p < 0.0048 and W = 0.7404, p < 0.0001 rrspeEtively). To achieve normality, the two meanires of dissolved oxygen ~1Whwere reduced to 1Wh and the arc sine of the square mot of dl of these values was caîcuiated (Shepiro-Wilks W test; W = 0.97 14, p < 0.15 12). Conductivity was üansformed to a log(1O) valw to achieve nonnality (Shapiro-Willrs W test; W = 0.9774, p < 0.3720). AU environmental variabks, including the normaîized dissolved oxygen and conductivity, were standardized by dividing the raw value minus the meen, by the standard deviaîion (i.e., standard deviates). These standardized values were the data usecl in the CCA dysis. CCA supplies a probability value @-value) of the relationship of the species data to the environmental variables and accoimts for the amount of interîommunity variation that is explained by these variables. This analysis assumes that taxa respond to enviromenta1 variables in a unimodal manner. The response of each taxon is compiled into a taxon score, which results in placement on a biplot (e.g., Figure 2-15). Each taxon appears on the plot nearest to the environmental variable to which it has the strongest unimodai respoase (ter Braak and Srnilaua

1998). Attention must be paid to sarnple size when interpreting CCA plots as sample sue may not be sufncient to produce the assumai unimodal response to the environmental variables.

Taxa Summaries The taxonomy used in this study is according to Turgeon et aï. (1998) for species and

Burch (1989) for subspecies identifications. The cornmon names for the taxa wmtaken from

Turgeon et al. (1998) unies othmnse indicated (Appendix I).

The information obtained for each taxon identifiai hm northern BC has been summdeû aml is discussed in Appendix 1. Each summmy includes a distribution map, collection site numbers, and a list of drainagcs/watersheds, ecoprovinces/ecoregions, and biogeoclimatic zones in which each taxon was found. For each taxon found at environmental sites, the mean, standard mr, and minimum and maximum measure of each environmental variable have been tabdated.

The iiiustrations accompmying the gastropod summaries were takm firom Bwch (1989) with the exception of Acmlo~coloruàe~~~is and Physella wghti, which were pvided by

Trent Hoover (gtaduate student at WC), and Ferrissia paralletus und Planorbella binneyi. which were taken fiom Cledre (198 1). The bivalve illustrations were taken fbm Clarke (1973b) with the exception of MarguritrierafoIcata aud Pisidum insigne. which were taken hmClarke

(1981), and Anodonta kennertyi, which was taken âom Burch (197%). All hinge illustrations for the gaius Piridium were takm hmHarington (1962). 23 Results and Discussion Collection Records

Collections wae made at 155 sites in northan BC, which when combined with histonc records availabie hm 40 sits provided a total of 195 sites. Total collections at these sites pmvided 1 108 collections identified by taxa (Table 2-2). Table A4 in Appendk 1 presents site descriptions and NAD83 coordinates for al1 sites.

Table 2-2. Record types, location map figure number, numba of records, number of collections and dates of collection of fieshwater moiîuscs hmnarthem British Columbia. Record numbm Location Number of Number of Dates of Collection Records Collections Mip I N1000-NI113 Figure 2-4 114 798 1997 and 1998 NO100 - NO140 Figure 2-5 41 170 1997 and 1998 CNlOOO-CN1024 Figure2-6 25 87 1972 and 1973 NMlûûû - MN1014 Figure 2-7 15 53 1875 to 1974 Tot& 19s 1108

Clarke (1981) indicaîed that thae wne 29 taxa of fnshwater gastropods in northem BC.

However four of these, Yafwtanicurinata, Fmsuria truncatirla, Stagnicola proximu and Physa

@na wen not found in field or museum collections and so have not been included in the synoptic listing of taxa confirmai to occu~in northan BC. Seven additional taxa of gastropods were discovd in this study. The cumnt study confinns the presence of 32 taxa of âeshwater gastropoâs in northem BC (Table 2-3).

Clarke (1981) indicated thet thek were 16 species of bivalves in northern BC including three species of mussels and 13 specics of sphacriid clams. One of the mussels, Anodonto beringiana, and one of the clams, Pisidium subtruncatum, were not fond in field or museum collections. Nine additionai @es of sphaeriid clams were discovered in this study. The cumnt study confirms the prescllce of 23 species Wwata bivalves in noahan BC (two Table 2-3. Systematic list of the freshwater molluscs of nortbem British Columbia. "*" indicates taxa not found at ecological sites.

Subclrrs Prorobnnchir ' Fudly Vrlvatidre FdyMaqpritiferidrt Valvata 1-i lewisi Mer, 1868 Margaritifaa fdcata (Gould. 1850) Valvata sincera sincem Say, 1824 Family Uaionidrt Anodonta Rennerlyi Lea, 1 860 Subclm Pulmonrta Fady Acroiord&t FaPlly Spbrerüdic Acroloxur coloradensis (J. Henderson, 1 930) Sphaen'um nitidum Westerlund, 1876 Sphaerium rhomboideun (Say, 1 822) Fainily Lymnredrc ' SphPenum simile (Say, 18 l?) Fossana galbana (Say, 1825) ~haeriumstnatinum (Lamarck, 18 1 8) Fossana modicella (Say, 1825) (Müller, porw 84 1) Musct(1ium lacusire 1774) Fossaria (Lea, 1 Mucvlium securik (Rime, 1 852) Lyninaeu atkaensis Dall, 1885 M'usc111ium tramemm (Say, 1 829)+ Lymea stagnalis oppressa (Say, 1 8 1 7) 179 1) 8 64) Pisidium casertumm (Poli, Stugnicola arctica (Lea, 1 Pisidium compresmm Prime, 1852 Stagnicda caperata (Say, 1 829) Pbidium conventus Clessin, 1877 Stagnicoïa catmcopium catuscopium (Say, 1 8 1 7) Pisidumfofax Sterki, 1896 Siognicola elodes (Say, 1 82 1) Pisidium fimginmm Rime, 1 852 ' Finlly Phyild8t Paidium ihhoense Ropa, 1890 Aplena efongata(Say, 1 82 1) PUiàium imigne Gabb, 1868 PIîidium lil#eborgi (Clessin, 1 886) Physa jennessi Dall, 1 9 19 + Pîysa skinneri Taylor, 1954 Pkidium milium Helà, 1836 Physella lordi (Baird, 1863)' Pisidium nitiàum Jenyns, 1832 Physella propinqua (Tryon, 1 865) fiidium punctoiirm.Sterki, 189s Physello vi@nea (Gould, 1847) Pisiàium m~trndotumPrime, l8S2* Physella wrigiiti Te aad Clarke, 1985 Pisidium va~bilePrime, 1 852 Pisiiiium venaicomm Rime, 185 1 ' FIpily PIwrbi&e Gy4ulw circuwurriatus (Tryon, 1866) Gytcltllw cristu (Linnaeus, 1858) Gymlrrr drjectu (Say, 1824) Gyratrlw ~~MIP(Say, 18 17) Helisoma anceps ancep (Me* 1930) Memtrrs opemtIaF (Gould, 1847) Planorbella binneyi (Tryon, 1 867) Planorbella subcrenata (Csrpenta, 1856) Planorbula amaigera (Say, 182 1) Planorbtrlu campest& Dawson, 1875 - Promenetus exacuous ~ucuous(Say, 1821) mussels and 2 1 sphaeriid clams; Table 2-3).

No non-native taxa of fkeshwater molluscs wae found in the course of this study. This precludes the evaluation of the hypothesis of alien species affecting the distniution of moIluscs.

A total of 55 taxa of hhwater moliuscs are now recorded fiom northern BC (Table 2-3).

Of these, 30 (55%) were unammon (i.e., found at I10 sites), 21 (38%) were cornmon (Le.,

found at 1 1 to 50 sites), and 4 (7%) weie very cornmon (i.e., found at >50 sites) (Table 2-8).

Site Locations

Freshwater molluscs were fond in al1 of the biogeoclimatic zones (Figure 2-2) and in

nine of the ten the major watersheds (Figure 2-3; no sites sampled in Tahi watershed) in

northem BC (Table 2-4). The numkr of sites within a particulai region depended on the size of

the ngion and on the accessibility of these areas for sampling.

Drainages Major Bi0gmcHm.ü~Zones Writtnhab I Pacinc Caastal n = 3 Boteal Black and White ~Pmce a = 94 n=84 Fraser n=47 CdWestemHemiock n=9

. . Arctic Liard n=58 n= 111

Table 2-4. Number of Wwater mollusc coiiection sites in the drainages, major watersheùs and biogeoclimatic zones in northem British Columbia.

Distribution The distniution meps (Figuns A-1 to A63 in Appendix 1) show that many of the kshwater rnolluscs were not found throughout the study area (i.e., their distributions weie non- randorn). Examination of the non-random distributions was made bas& on climate, glacial history and dispersal factors.

Climate

Climate conditions within the study area were available hmthe biogeoclimatic (WC) zone classification system (Figure 2-2), which incorporates climate, soi1 and vegetation data into large-scale mnes of similarity (Meidinger and Pojar 1991). nie climate characteristics that distinguish the BGC zones within the study area are presented in Table 2-5.

BGC Elevrtioa Mtrnaonad Months Months rnnurl rmount of Zone (m) temp CC) kknO°C above 10°C predpitation pndpitition (mm) as snow (%) BWBS 230 - 1300 -2.9 to +2.0 5-7 2-4 330- 570 35-55 CWH O - 300 5.2 to 10.5 O 4-6 1OO0-4400 40-50

SWB 900 - 1500 -0.7 to -3.0 da 1 460- 700 35-60 Valley bottoms -1300 1.7 to 5.0 4-5 2-5 440- 990 25-50 Table 2-5. Summary of altitude and climate idonnation for the biogeoclimatic zones in northern British Columbia (Meidinger and Pojar 1991). BWBS = Bonal White and Black Spnics; CWH = Coastai Wcstem Hdack; ESSF = Engelmann Spnice - Subalpine Fir, ICH = htcrior Cedar - Hemiock; SWB = Spruce - Willow - Birch; , SBS = Sub-Bord Spce. Sa Figrin 2-2.

Climate factors afkct watcr tempcrature, which in turn affkcts life history traits such as pwthrate, age of rnaturity, and fccundity levels in freshwater prosobmchs (Aldridge 1983), puhonates (McMahon 1983) and bivalves (Burky 1983). Some âeshwater mollusc taxa may be restricted to climatic regirnes pviding sufficient days of elevatd water temperature for completion of th& life cycle.

Fdieswith taxon distriiutions that may have becn infiuenced by climate were: Famüy Acroloxidae - Acruloaw coloradensis (Figure A-4) was fond only in the Sub-Boreal Spruce biogeoclimatic (BGC) zone in the southeast of the study area (Figure 2-2). This zone has a meaa amual tempetanire above OOC and more months above lOOC than do the more northerly

BGC zones (Table 2-5). However, if A. coloradenris was restricted to the south of the study area by climatic requirements, it would be expected to also occur fÙrther south in the province but this has not been verified to date.

Family Lymoaeidae - Fossaria pana (Figure A-7) and Stagnicola catarcopium catarcopium

(Figure A-13) wae found only in the south of the study area in a variety of BGC zones.

However, both species occur elsewhere in Canada northerly latitudes (Clarke 198 1).

F8dySphreriidre - SphamWumrhomboideum (Figure A-43) was found only in the Sub-Boreal

SpceBK zone in the south of the study as deScnbed for Family Aaoloxidae above. As this distribution corresponds to the northem limii of its range elsewhere in Canada (Clarke 198 1), it appears that the distribution of S. rhomboideum may be influenced by climate.

Glacial History

The last major glaciation began about 30,000 years ago and ended about 10,000 years ago

(Cannings and Canniags 1996). Most of BC became covered by ice during this period as a result of the Cordillaan ice sheet spnading hmthe West and the Laurentide ice sheet spreading fiom the east. However9 there were thne large areas adjacent to these ice sheets that escaped glaciation (McPhail and Lindsey 1970) and pbably acted a refuge for many aquatic organisms including nrshwater moliuscs. Thcse are: (1) the Berhg Refuge (Figue %Ba), which included a large part of the Yulron Riwr basin; (2) the Pacifie Refuge (Figure 2-8b) almg the coast of what is now Califomia, ûregon and southem Washington and; (3) the Mississippi Refuge (Figure 2-

8c) in the northem tributaries of the Gulf of Mexico drainage. It is lîkely that organisms within the refbgia dispased behdthe mehgice sheets, as indicated by the amws in Figure 2-8. Stratigraphie evidence indicates the two ice sheets made contact in only a few places in the Liard Plateau in northern BC leaving some of this area unglaciated (Prest 1976). It is also possible that there were mountain summits (nunataks) proüuding through the ice sheet (Pielou

199 1) and some molluscs may have SUNived in high mountain lakes in these nunataks.

(a) Bering Rcfitgt ad ..m.Wyfm

Figure 2-8. Dispasal routes of fieshwater fishes hmthe (a) Bering, (b) Pacific and (c) Mississippi ttfirgia. These pattcms may also be reflected in dispersal patterns of îreshwata molluscs. Ana of refbge hmthe ice sheet is stippled. Dispasal routes are indicatcd by amws. Dotted lines delineate major drainage areas. (From McPhail and Lmdsey 1970.)

DisPnsal Passive dispersal of mollusc talres place when they are moved by mechanisms in which they play no active part Occasional fioodwaters may carry eggs or ad* to new locations, and mal1 mils and clams can becorne lodged in the feathers or in the mud on the feet of aquatic birâs (Mackie 1979). Freshwater clams can ais0 be transported by large aquatic insects (Clarke 198 1) and salamanden (Davis and Gilhen 1982). While passive dispersal allows many molluscs to üanscend geographic and drainage-system boundaries, there may be some barriers that present an insunnountable obstacle to some taxa. In northern BC, the most apparent geographic barrier is the Rocky Mountains.

Panans that may be indicative of glacial phenornena or obstruction by geographic barriers are apparent in seven of the nine families of fieshwater molluscs in northertl BC (not apparent in Valvatidae or Sphaeriidae). These families are:

Famiiy Acroloridae - Fossil evidence indicates that A. coloradenris was once more widespread in North America (Bryce 1970). As it is cwrently most co~nmonlyknown in western North

America hmdisjunct locations in the Rocky Mountains (i.e. northern BC, Montana and

Colorado; Lee and Ackennan 1999c), it may have swvived glaciation in lakes in nunataks. Its cumnt limited distribution may reflect a limited capacity for pst-glacial dispasel away hm these mal1 nfugia although the possiôle location of these refiigia has not ôeen examineci.

Fadiy Lymnieidae - Of the nine taxa of lymnaeids cdlected in northem BC, five displayed distributions that were not intcrpntable based on hypothesized pst-giacial dispasion mutes.

Of the remaining four taxa, L. athemis (Figure A-8) is recognized as a Berhg Refuge species

(Clarke 1981), which concurs with the hdings of this study. Fossuria galhnu (Figure A-5) and

Stugnicola cuperatu (Figure A-12) were fomd only east of the Rocky Mounîah, suggesting

their migration fbm the Mississippi Refuge may have been halted by the geographic barria

posed by these mountains. Fossuriu purva (Fi* A-7) was found only in the Pacific drainage

but has been found elsewhere Ui Canaàa so its limited distniution in this shidy is not ndy

indicative of migration from the Pacific Refbge.

Fady Physidae - Aplaur elongata (Figure A-16) and Physa skinneri (Figure A-19) were found

in both the Pacifie and Arctic drainages displaying w interpetable patterns of distriiution. As 30 most contemporacy Physella collection were not identifid to species, and historic Physella collections were sparse, no distribution patterns could be discernai for most of this genera. The exception was Physellu wightt, which is endemic to the Liard River hotspriags cornplex (Figure

A-23). This hotsprhgs is in the area of the Liard plateau believed to have remained unglaciated during the last ice age. P. wrighti is believed to have survived glaciation and may have been present at this site for about 100,000 years (Te and Clarke 1985).

Family Planorbidae - Of the 1 1 taxa of planorbids in northern BC, eight displayed distributions that were not interpretable based on hypothesized pst-glacial dispersion routes. Of the remaining three species, Menetus operctllaris (Figure A-29) and Plonorbella bin~eyi(Figure A-

35) are confmed to the Pacific drainage suggesting pst-glacial dispersal hm the Pacific

Refuge. Planorbula annigera (Figure A-31) was found only in the Arctic drainage east of the

Rocky Mountains suggesting its migration from the Mississippi Refuse was halted by the

Fady Ancylidrc - Ancylidae have not bem pmiously recordai in northern BC (Clarke 198 1) although this study found F. parallelus to be commoa. F. porollelus (Figure A-38) was more . cornmon in the south of the snidy ana but was occasionally collectecl hm large lakes in the north.

FaaUks Maryritiferidle rnd Unionidic - Both Margariiifeero falcata (Figure A-40) and

Andonta kennedyi (Figure A-41) were fouad in the Pacific drainage but A. kennerlyi was also

found in the Arctic drainage in the upper Peace River watersbed. Fnshwater mussels owe th&

distributional patterns to the ranges of th& fish hosts (Waaers 1992) and it is believed Pacific

fish species entcrcd the upper Peace Riva watershed duiing a relatively ment minor headwater

transfer, as few of the fish spMes have dispascd much farther down the Peace than the

AlmCborder (McPhd and Lindsey 1970). This is also the apparent distribution for A.

31 kennerIyi (Clarke 1981), and the headwater transfer may have included these mussels or fish carrying th& glochidia. The pst-glacial dispersal of M. jùlcata may have bem slown in its northward movement so that it, or its fish host(s), may not have been available for headwater tramfa. M. fakata has still not been found as far north as has A. kennerlyi.

Environmental Data

Water conditions may set limits on the distributions of ûeshwater molluscs (see review in

Lodge et al. 1987). The environmental data collected in this study provides a bais for initiating merfield and laboratory studies on the ecology of fkshwater molluscs and should not be interpreted as definitive ecological requirements for any of the taxa found. The range plots

(Figures 2-9 to 2-14) show that common taxa often tended to be found over a wide range of environmental conditions whenas las common taxa tended to be found within narrow ranges.

This rnay be a consequence of sample size. Without Mer scimtific testing, it cannot determineci if these more limited ranges are artifacts of fma collections or if they are

The water conditions mdin this shdy and the relationsbip of these variables with the disûibutioa and ecology of fnshwater molluscs arc as follows:

(1) Water temperature: With the exception of Physella wrighti, wbich lives in a hotsprings sûeam, the hhwater molluscs of wnhem BC pobably tolerate cold weta temperatUries for part of the year. However, there rnay be differences in th& abüity to tolaate higha temptures. This may resûict some molluscs to nmning water or to large water bodies that are not as susceptible to the magnitude of ambient heating as are derwater bodies.

(2) Dissolwd Oxygen: Two types of respiratory mechanisms occur in tnily aquatic fkeshwatn snaüs (Berg and Ockeham 1959) and in sphaerüd clams (Burky 1983): (1) Oxygen- independent - these taxa tend to maintain a constant oxygen co~lsumption,despite a lowering of dissolved oxygen levels and so cm maintain their physiological functions under reduced oxygen conditions. These taxa are tolerant of prolonged hypoxia and can live in a wide variety of habitats; and (2) Oxygendependent - these taxa exhibit a slow reduction in oxygen comption as the dissolveû oxygen levels decrease and so physiological fiinctions are depressed under reduced oxygen conditions. These taxa are intolerant of prolonged hypoxia and are restncted to well-oxygenated habitats.

(3) Conductivity and Calcium Concentration: The concentration of dissolved calcium (which in this study was derived hm the conductivity measure) is ofien considered a major factor detennining the distribution of freshwata molluscs (reviewed by Brown 1991 for snails, and by

McMahon 1991 for bivalves). Calcium is an essential material for molluscan shell construction and egg development, and affects pwthrate, swivomhip, and fecundity rates in âeshwater pulmonate snails (McMahon 1983).

(4) pH: The pH, which is a meam of acidityIalkalinity, is ofken coasidered a major factor deteïmining the distriions of âeshwater mails (Bm1991), whaeas McMahon (1991) states that ambient pH does not greatly bitthe distniution of fkhwata bivalws. Low pH is gcnerally associatd with low calcium concentration and with levels of cerbon dioxide that probably irnpede gas exchange (Fuller 1974). High pH is associated with high calcium levels and tbese Mitats are usuaily Bssociatcd with stieems draining limestone catchments (Thorp and

Covich 1991). As pH and calcium concentrations are Wed, pH may be cqually as important as calcium in determinhg the distribution of âeshwater moiluscs.

Meammats of the four water conditions âiscussed above were taken at 114 sites (1 13 sites for pH). These values plus the calcium concentration derived hm the conductivity memm are presented in Table A-l (Appnidix 1) and are summarized in Table 2-6. Molluscs

found a. 108 of these sites. The enviromenta1 variables at these 108 sites differ hmthe values for all 114 sites presented in Table 2-6 in that the range of pH was less (range hm5.15 33 to 9.25). The mean pH of the six sites where molluscs were not found (6.19 I0.63) was

' significantly lower than for the 108 positive sites (7.42 i 0.08; p = 0.01). nie dissolved oxygen

saturation was above 100%in two large lakes with a dense floating algal blooms.

Table 26. Sample size, mean, standard enor and range for the environmerital variables measwd at the ecological sites in northem British Columbia. Environmental Variable Sample Mern Standard Range SIze Error v I Temperature (T) 114 18.8 0.43 1.5 - 35.5 Dissolved Oxygen (% Saturation) 114 67.9 2.15 7.0- 135 Conductivity (psimens) 114 280.8 ' 23 -95 19.7 - 1568 Dissolvd calcium (mghe) 114 36.3 3.57 1.2 - 209.3 ------I pH r ii3 r 7.35 r 0.08 I 3.95 - 9.25-1

T-tests The resuîts of t-tests on the means of the environmental variables showed mmy

significant differences between taxa in the families or genera examineâ (Table 2-7). Howeva, it

was not the mean tbat appeareà to be the most important statistic. Maximum wata temperatUrey

minimum dissolved oxygen saturation, and minimum conductivity/caicium concentration

pvided bctta indications of cnvironmcntal daerminants of taxa occurrence than did the mean

of these measirrcments. The mean pH was usefbi in deteminhg if taxa appeared to prefer acidic

(i.e., < 7) or aikaiine (Le., > 7) conditions but differences in mean pH.that may reflect eoologicai

differences were more easily asscsed fhm the range plots (see below).

Range Plots

The range plots of the environmental data coliected for each taxon are shown for the six

pups in Figures 2-9 to 2-14. These show that memoliuscs were fond over a wide range of

the environmental veriables wh- others sean mon restricted in the range of conditions under

which they wmfomd to occur. These plots tàditated assesanent of the possible ecaiogicai Table 2-7. Significant differencei and de- of fieedom (df) in means of enviromentai variables found within the pupsor subgroups of frcshwater mollusc compared. Ëk. Variable

Fossatta galbana > Fossaria pana F. modicella > F. parva Lymnaea atkemis > F. pana Lymnaea stagnalis appressu > F. parva Stagnicola arctica > F. pawa S. caperata > F. pana S. elodes > F. pania Stagna'cola sp. juveniles > F. parva Dissolved Oxygen Lym~eastagnalis appressa > S. arctica L. stagnafis appressa > S. caperata Staigniola catascopium > Fossuria pana CoDductiVity Fossana dicella > Lymnaea stagnalis appressa F. nodicella > Stagnicola elodes S. caperata > L. stagnalis appresa S. caperata > S. el& Fossuna gaiba~> Fmsurio potvu E galba^ > Stargicola caperata F. modicella > F. pana Physella spp. > Physa skinneri Physeila wnghti > Aplexa efongata P. wnghti > P. skimeri

-- P. wnghti > Physella spp. Conductivity Physofa wnghti > Aplm elongata P. wnghti > PhyseIla sùinnenn P. wnghti > Physella sp. Physa skimeri > Aplexn elongata P&ella spp. > A. elongata

Conductivity G. panw > Helisomo ancep anceps G. puma > M. opetcuk" P. exacuous tmcuow > M. operculatis Planorbula unnigerri > Planorbella binneyi H. anceps anceps > M. o~lmis Plamhlla svbc~nata> M opercuiaris Table 2-7 (cont.) Significant differetlces and degrees of fieedom (df) in means of environmental variables found within the groups or subgroups of fieshwater mollusc wmpd.

------Group Taxa compued p-value 5 Anodonta kennerlyi > Mu~uriiiferafakata p = 0.028 p = 0.018 P. ventncosum > P. idahoense p = 0.036 Dissolved Oxygen P. compressum > P. vennicosum p = 0.022 P. idahoeme > P. ventra'cosum p = 0.019 Conductivity PrSidium milium > P. compressum p = 0.030 P. miliurn > P. ihhoeme p = 0.0 16 P. nitiàum > P. idahoense p = 0.045 P. compressum > P. ventricosurn p = 0.012 P. conventtu > P./emgiiieum p = 0.040 P. conventu > P. imigne p = 0.006 P. convenrtrs > P. milium p = 0.029 P. conventus > P. pnctatum p = 0.006 P. coriventus > P. ventncasum p = 0.019 P. conventus > Pisidhm sp. p = 0.003 P. idahoeme > P.jêmgineum p = 0.024 P. iâhhoeme > P. müium p = 0.015 P. idphuellse > P. ventncosum p = 0.004 P. i&hme > Pdidium sp. p = 0.037 P. nitidrrm > P. ventncomm p = 0.055 P. Ntidirm > Pkidium sp. p = 0.054 requirements of individual taxa as the minimum, maximum, mean and range of the variables could be easily rd,and the diffhnces in the range of conditions mdbaween taxa oould be readily compareci.

Canonical Correspondence Anarysis (KA)

The CCA plots, significance lm1 (p-vaiue) of the 6Rt canonical axis (i.e., nlationship of the taxa to the environmental variables) and cumulative percent variance of the taxa data are shown for each of the six gmups in Figures 2-15 to 2-20. These analyses show that for al1 of the gastmpod groups (Groups 1 - 4; Figures 2-15 to 2-18), the environmental variables sigaificantly affecteci the pesence of mails @ < 0.05) whereas this was not the case for the bivalves (Oloups

5 and 6; Figures 2-1 9 and 2-20; p > 0.05). For those taxa that had sample &es adequate to show a unimodal response (i.e, n 1 4, very few showed any stmng responses to 36 Figure 2-9. Group 1 : Range and means of environmental variables measured foi Family Valvatidae, Family Amloxidae and Family Ancylidae. " 1 " indicates mean. Minimum calcium coacenüation is indicated on plot (c).

Jal Temneritun

Valvata lewisi lewisi (n = 32) Valvata sincera sinceru (n = 29) Acroloxus coloradensis (n = 7) Ferrissia parallelus (n = 23)

Di~solveàOmen Valvatu lewisi lewisi (n = 32) Valvata sincera sincera (n = 29) Acroloxus coloradensis (n = 7) Femssia parallelus (n = 23)

Valwta lewisi lewisi (n = 32) Valvata sincera sincera (n = 29) Acroloxus coluradenis (n = 7) Fewbia parallelus (n = 23)

Valvata 1Wilewisi (n = 32) Valvata sincera sincera (n = 29) Acmlanr~colorhris (II= 7) Ferrissia parallehs (n = 23) Figure 2-10. Group 2: Range and mem of environmentai variables measured for Family Lymnaeidae. " 1 " indicates mean. Minimum calcium concentration is indicated on plot (c).

Fossaria galbana (n = 4)

Fossaria modicella (II= 8) 1.5 Fossaria purva (n = 14) Lymnea atkuensis (n = 2) Lymnaea stagnalk appresa (n = 25) Stag&olu arctica (a = 15) Stagnicola caperata (n = 3) Stagnicola cutuscopium (n = 3) S~agnicolaelodes (n = 46) Stagnico fa sp. -juwniles (n = 4)

Fossaria galbana (n = 4) Fossuria nodicella (n = 8) Fossotia pama (n = 1 4) Lyninea utkaensis (n = 2) Lymnae4 stugmlis appmsa (n = 25) Stagnico fa arctica (n = 1 5) Stognicolu caperuta (a = 3) Stugnicola catc~pcopium(n = 3) Stagnicola elodes (n = 46) Stagnicola sp. -juvenilos (n = 4) Figure 2- 10 (cont.). Gmup 2: Range and means of environmental variables measurcd for Family Lymnaeiâae. " 1 " indicates mean. Minimum calcium concentration is indicated on plot (c). lc) Conductivitv and Calcium O 200 400 600 800 LOO0 pS O 29 58 88 118 148 md Fossaricr galbana (n = 4) Fossaria modicellu (n= 8) Fossaria parva (n = 1 4) Lymnea atkaensis (n = 2)

Lymnaea stagnalis appressa (n = 25) Stapicola arctico (n = 15) Stagnicolo caperata (n = 3) Srognicola catascopiunt (n = 3) Stugnicofa elodes (n = 46) Stagniculu sp. -juveniles (n = 4)

Fossaria galh(n = 4) Fossaria mdicello (n = 8) Fossariu parw (n = 14) Lymnea atkaensis (n = 2)

Lyrrm4rea stagnalis appressa (O = 25) Stagnicola arctica (n = 15) Stagnicola caperata (n = 3) Stagnicola c~tascopium(n = 3) Stagnicollo elodes (n = 46) Stagnicola sp. -juveniies (n = 4) Figure 2-1 1. Group 3: Range and means of enviromentai variables measu~edfor Family Physidae. " 1 " indicates mean. Minimum calcium concentration is indicated on plot (c).

Aplexlr elongata (n = 3) Physa skinneri (n = 4) Physella wnghti (n = 1) Physella spp. (n = 50)

Aplm elongata (n = 3) Physa skinneri (n = 4) Physella wrighti (n = 1) Physella spp. (n = 50)

(cl ConductMtv and Caicium O 200 400 600 800 1ûûûpS O 29 58 88 118 148 mgil Aplexa elongata (n = 3) J 12.1 mg/N (n I Physa skinnen' = 4) 27.4 1 Physella wnghti (n = 1) -*O 1 lUpS 17imgll I Physelia spp. (n = 50) 18.1 I hi8 m Aplexcr elongata (n = 3) Physa skinneri (n = 4) Physella wltghti (n = 1) Physello spp. (n = 50) Figure 2- 12. Group 4: Range and means of environmental variables measured for Farnily Planorbidae. " 1 " indiates mean. Minimum calcium concentration is indicated on plot (c).

Ja) Temmrrtiuc

Gyraulus circumtn'utus (n = 65) 1.5 GyriauIlls criSta (n = 4) Gyroulw depectus (n = 26) Gyrrufus pam (n = 20) Menetus opercularis (n = 1 O)

Promeneîus ~XL~CUOUS(n = 28) Planorbula onnigera (a= 1) Planorbula cumpesrns (n = 4) Helisoma anceps anceps (n = 7) Planorbella binneyi (n = 2) PlanorbeIIa subcrenata (n = 35)

pl Dbrolvcd 0-n Gyraulus cinrmrtnàtus (n = 65) Gyraulus crista (n = 4) Gymulrur &$lecm (n = 26) Gyraulus ponu (n = 20) Menetus operculuris (n = 10)

Promenetus exacuous(n = 28) Plunorbulu armigera (n = 1) Planorbula camptris (n = 4) Helisoma anceps ancepr (n = 7) Planorbda binneyi (n = 2) Pùanorbeiia subcrenata (n = 35) Figure 2- 12 (cont.). Group 4: Rauge and means of enviromentai variables measured for Family Planorbidae. " 1 " indicates mean. Minimum calcium concentration is indicated on plot (c). le1 Conductivitv and Caicium

Gyraulus circumtriatus (n = 65) Gyroulus crista (n = 4) Gyraulus defletus (n = 26) Gyraulus pom (n = 20) Menetus operc11iuri.s(n = 1 O) Promenetus exacuous(n = 28) Planorbula annigeru (n = 1) Planorbula campestris (n = 4) Helisoma anceps anceps (n = 7) Planorbella binneyi (n = 2) Planorbella subcrenata (n = 35)

Gyraulus cireums~uttis(n = 65) Gyrculus crista (a = 4) Gyraulus dejlectus (n = 26) Gyniulus parvus (n = 20) Menetus opercu1ari.s (n = 10)

Romenetus ~X~CUOUS(n = 28) Plonorark, amigera (n = 1) Planorbulu camptris (n = 4) HelLoma anceps anceps (n = 7) Planorbella binneyi (n = 2) Piunotbeh mbmenato (n = 34) Figure 2-1 3. Group 5: Range and means of environmental variables measrned for Family Margaritifendae, FdlyUnioniâae and Family Sphaeriidae; genus Sphaerium and genus Mt~i~cuJium." 1 " indicates mean. Minimum calcium concentration is indicated on plot (c). J- J-

Margariti/erafoIcaio (n= 4) Anodonta knnedyi (n = 12) Sphaerium nitidum (n = 14) Sphaerium rhomboideum (n = 1) Sphaerium simile (n = 8) Sphaerium stnàtinum (n = 1) Musculium lacuïhe (n = 33) Musculium securis (n = 36)

Matguritriferaafacata (n = 4) Anodonta kennerlyi (n = 12) Sphaeriurn nitidum (n = 14) Sphaetîum rhomboideum (n = 1) Sphetium simile (n = 8) Sphaerium stri*utintîm (n = 1) Msculium lacustre (n = 33) Mwculium searis (n = 36)

Mu~aritifwafalcuta (n = 4) Anodonta kenérlyi (n = 12) Sphaerium nitidum (n = 14) Splamenwnrhomboidewn (n = 1) Sphaerim simile (n = 8) Sphaerium stnàtinum (a = 1) Mt(scuIium Zacustre (n = 33) Mwculium senvis (n = 36) Figure 2- 13 (cont.). Group 5: Range and means of environmental variables measured for Family Margaritiferidae, FdyUnionidae and Family Sphaeriidae; genus Sphaerium and genus Musculiluni. " 1 " indicates mean. Minimum calcium concentration is indicated on plot (c). IglnE! M'urgarih~rafoIcata(n = 4) Anodonta kennerbi (n = 12) Spheriwn nitidum (n = 14) Sphaerium rhomboidewn (n = 1) Sphaetitm simile (n = 8) Sphaerium shiatinum (n = 1) MwmIiiwn lact(stre (n = 33) Murcifium seans (n = 36) Figure 2- 14. Group 6. Range and means of environmental variables measured for Family Sphaeriidae, gmus Pisidim. ^ ( " indicates mean. Minimum calcium concentration is indicated on plot (c). la) Tem~errhin

Pisidium casertanuin (n = 6 1) 1-5 Pisidium cornpressun! (n = 20) Pisidium cmvenius (n = 6) Pisidium fillux (n = 2) Pisidium femgineum (n = 1 9) Pisidiurn idahoense (n = 12) Pisidium insigne (n = 1) Pisidium lilueborgi (n = 13) Pisidium milium (n = 17) Pisidium nitidum (n = 9) Pisidium punctahcm (n = 1) Pisidium variabile (n = 36) Pisidiutn venhicosum (n = 23) Pisidium sp. (n = 1)

Jbl Disrolveâ Oxvgen

Pisidium cosertanum (n = 61) Pisidium compressum (n = 20) Pisidim conventus (n = 6) Pisiditîm foIJax (n = 2) Pisidium ferrugineum (n = 19) Pisidium idahoense (n = 12) Pisidium insigne (n = 1) Pisidium lilljebogi (n = 13) Pisidium milium (n = 17) PisUium nitiàum (n = 9) Pisidiurn punctutum (n = 1) Pisidum variabile (n = 36) Pkidiurn venlricostlrn (n = 23) Pisidim sp. (n = 1) Figure 2- 14 (cont.). Group 6. Range and meam of environmental variables memurd for Family Sphadidae, gmus Pisidium. " 1 " indicates mean. Minimum calcium concentration is indicated on plot (c). Je1 Conductivitv and Calcium

Pisidium cmertanum (n = 6 1) Pisidium compressum (n = 20) Pisidium conventus (n = 6) P isidiumfallax (n = 2) Pisidium femgineum (n = 19) Pisidium idahoene (n = 12) Pisidium insigne (n = 1) Pisidium liI&eborgi (II= 13) Pisidium miliurn (n = 17) Pisidium nitidum (a = 9) Pisidium punctattîm (n = 1) Pisidium variabile (n = 36) Pisidium ventricoswn (n = 23) Pisidium sp. (n= 1) lolPaC Pisidium casertantlm (n = 61) PLridium compresmm (n = 20) Pisidium conventus (n = 6) Pisidiurnfarax (n = 2) Pisidium fentlgineum (n = 19) Pisidiuni ihhoense (n = 12) Pûidium insigne (n = 1) Pisidium lilljboorgi (n = 13) Pisidhm miliwn (n = 17) Pisidm nitidum (n = 9) Pisidium puncta~rn(n = 1) Pisidium variabile (n = 36) Pisiditlm ventn'cosum (n = 23) PLridum sp. (n = 1) Figure 2- 15. Canonical Cornespondence Analysis of environmentai variables and taxa fiom Group 1 (Family Valvatidae, Family Acroloxidae and Family Ancylidae).

Test of significance of first canonical axis: F-ratio = 5.574 pvalue = 0.040 Cumulative percent variance of species data: 13.2%

Leymd VAU = Valvata /Milewiri (n = 32) VASS = Valvuta sincera sincera (n = 29) ACCO ACCO = Acroloxus coloradensis (n= 7) FEPA = Ferrissia paralIelus (n= 23)

Figure 2- 16. Canonid Correspondence Analysis of environmentai variables and taxa hm Group 2 ( Family Lyxnnacidae).

Test of significance of first canonical axis: F-ratio = 3.669 pvalue = 0.010 Cumulative percent variance of species data: 6.3% m FOGA = Fossa~ galba^ (n = 4) FOMO = FOSS~Mmodicelkr (n = 8) FOPA = Fossaria parva (n=14) LYAT = Lywwuaea atkaemis (n=2) LYSA = Lymnriea stagaalis appmsa (n = 25) STAR = Stagnriola antica (n = 15) STCA = Stagnicolo caperata (n = 3) STCC = Stagnicola catascopium (n = 3) STEL = Stagnicola elodes (n = 46) STSP-I= Stagnicola sp. juvdes (n = 4) Figure 2- 17. Caonical Correspondence Analysis of environmental variables and taxa hm

Test of significance of iïrst Dû = dusolvad oxygcn = COND = cductivity canonical axis: F-ratio 1O. 1 Sî pvalue = 0.005

Cumulative percent variance of species data: 23.6%

@€%Id APEL = Aplexa elonguta (n = 3) PHSK = Phyw skinnen (n = 4) PHWR = Physella wnghti (n = 1) PHSP = Physellu spp. (n= 50)

Figure 2-1 8. Canonid Correspondence Analysis of environmental variables and taxa hm

Test of significance of fbt canonical axis: F-ratio = 5.159 pv* = 0.005 Cumulative percent variance of species data: 8.8% Ia!ad GYCI = Gyrrnrlw cimmttiatus (n = 65) GYCR = GynnrZw crista (n = 4) GYDE = Gpaulus doflctirr (n = 26) GYPA = Gyi.puiuspam (n = 20) MEOP = Menetus opetrularis (n = 10) PREE = Promenefus ~~OCYOYP(n = 28) PLAR = Planohla annigera (n = 1) PLCA = Pl411orbula campestris (n = 4) HUA= HeZkonw anceps anceps (n = 7) PLBI = Planorbella binneyi (n = 2) PLSU = PlanorbeZla subctenata (n = 35) Figure 2-19. Canonical Correspondence Analysis of environmental variables and taxa hm Group 5 (Family Margaritifendae, FdyUnionidae and genus Sphuerium and Musculium of Family Sphaeriidae).

Test of significance of first canonid ais: F-ratio = 2.123 pvaiue = 0.480 Cumulative percent variance of species data: 5.1 % Legend MAFA = Margarin~rajàlcata(n = 4) ANKE = Anodonta kennerfyi (n = 12) SPNI = Sphaerium nitidum (n = 14) SPRH = Sphueriwn rhomboideuni (n = 1) SPSI = Sphaerium simile (n = 8) SPST = Sphaerium sniatinum (n = 1) MvLA = Mt(scufiumlacustre (n = 33) MUSE = Mdiumsecuris (n = 36)

Figure 2-20. Canonical Correspondence Anaiysis of environmental variables and taxa hm Group 6 (gaius Pisidiwn of Famüy Sphaaiidae). Test of significance of nrst canonical axis: F-ratio = 2.27 1 p-value = 0.225 umulative percent variance of species data: 3.7% ;nceo CA = Pisidiivn casertanum (n = 6 1) CO = Eidium cotnpmmm (n = 20) M = Pisidium cornentirs (n = 6) FA = Pisidium~llax(n = 2) E= Pisidiumfemrgineum(n = 19) Dl= Pisidium idahme (n = 12) W = Puidium insigne (n = 1) ILI = Pisidium IilQeborgi (a = 13) IMI =Pisiàium milium (n = 17) PII =Pisiditun nitirlirm (n = 9) iw =fiidium punctatum (n = 1) NA =Pisiàium variobile (n = 36) NE =P&idium ventn'comm (n = 23) [SP=Pisidiuni JP. (n = 1) single or combinations of environmental variables (Le., they were located near the origin on the plots or between environmental variable arrows). In some cases (e.g., Volvata sincera sinceru,

Ma~arit~erafoIcataand Anodunta kennerlyi) these responses concdwith data extrapolated fiom the range plots. The responses are discussed in the group analyses that follow.

Analysis of the environmental data yielded the following information for each family or genera examined:

FadyVaivatidae - nie plots in Figure 2-9a indicate that neither of the Valvata taxa appean to be reshicted to cool water temperatures (i.e., < 25OC).

The two Valvata taxa occinred at very similar ranges of dissolved oxygm and had very similar means (Figure 2-9b). While prosobmchs are generally described as las hypoxia toi-t than pulmonates (Boymtt 1936), this may not be the case for these valvatids as they were found at very low levels of dissolwd oxygm (I15% saturation) and, thmfore, may be oxygen-independent .

The two Valvuta taxa were found ova broad ranges of conductivity/calcium concentration, but they wen not coilected at the sites with the lowest values mdin this study (Figure 2-9c). It may be that these taxa are physiologically prohibited fiom inhabithg habitats with very low levels of calcium and that this may be a limiting factor in the number of habitats availabîe to them in northem BC.

Pennak (1989) states that dl Vdvatidae are confined to watas having pH reaâings of 7.0 or above. However, in this shidy, Y. lewisi lewisi was found at pH as low as 5.6 and Y. sincera sinceru as low as 6.5 (Figure 2-94. The lower pH tolerance of Y. Iewisi lewisi may dow it to occupy a wida range of habitats than Y. sincera sincem.

Thtce families were included in the CCA analysis îhat includes the Valvata taxa (Group

1; Tabie 2-1). The resuits (Figure 2-15) wcn tbat these fàdïes responded sipnificantly to environmental variables @ = 0.04), d the variables 8ccounted for 13.2% of the variance in taxa 50 presence at the sites examined. The plot shows that the presence of Y. lewisi lewisi corresponded

, to lower than average temperature and dissolved oxygen, neither of which appeared to be

particularly important in its ecology as extrapolateci hmthe range plots. However, Y. sincera

sincem presence co~espondedto hi@ than average pH, which may be an ecological factor for

this species as discussed above.

Famiiy Acroloridae - Acroloxis coloradensis was found only in habitats with water temperature

< 24.5' (Figure 2-9a). ûther factors suggest that A. coloradensis may be cestriacd to stable,

perennial habitats (see below) and lower temperatures may be characteristic of these types of

habitats.

A. coloradensis was only collected hm habitats of relatively high dissolved oxygen

saturation (> 40%; Figure 2-9b). Eumian species of Acroloxfls are oxygendependent (Russell-

Hunter 1978) and A. coloradensis may also be limiteci to well-oxygenated habitats. This may

restrict the its disüibution to perennial habitats with relatively stable conditions.

A. colorodemis was collected at a minimum dcium concentration of -10.1 mgA calcium

(Figure 2-9c). However, sites with lower messuns ocmed only outside of the physical

distri%ution range for A. coloradensis. Thus, it camot be discemed if this calcium level is a

minimum requirement for A. coloradensis, if it is a remit of a range nstricted by other factors, or

if it is an artifa of mal1 sample size (n = 7).

A. colordensis is one-of the few moiluscs m this stuây found in habitats with acidic

mean pH, although it was also found in alkaline conditions (Figure 24). It may be tbt

perennial, stable habitats within the range of A. colodensis tend to k acidic and that a

prefmnce for acidic water is no! a distinctive characte&ic of the species.

Thfamilies wae includd in the CCA dysis thet included A. coloradensis, as

desm'bed for Valvatidae (Figure 2-15). A. coloradensis occurs on the plot most closely corresponding to lower than average pH, which is consistent with the obsewations hm the

range plot of pH (Figure 2-9d).

Fady Lymnaeiàae - Fossariu guibana. F. pana. Lymnaea atkaemis and Stagnicola catascopium catoscopium were found only at wata temperatures < 25OC (Figure 2-10a). Both F.

galbona and L. utkaensis are cold-water species (Clarke 198 1) and weie only collected hm

., large lakes, as was S. cataïcopiuni catuscopiunr. The collections of F. pawa were ofien associated with mail sûeams with relatively low temperatures (see Chapter 4) but as this species

is amphibious (Clarke 1981), it rnay have a bdertolmce for temperature variation than

indicated by water temperature. All other lymnaeids were collected at temperatures > 25T

(Figure 2- 1Oa) and so do not appear to have their distributions limited by temperature in northem BC.

As lymnaeids main dependence on aûnosphaic air, the dissolved oxygen content of the

water should not be a lirniting factor in distribution. The relatively large mount of variabiiity in

the minimum for dissolved oxygm levels (Figure 2-lob) may be indicative of otha factors. For

example, laice species wae found in habitats of relatively hi@ dissolved oxygen.

FossurÙa galbana (n = 4), F. dicella (n = 8), Lymnuea athemis (n = 2) and stagnicola

caperata (n = 3) wae found at sites with calcium concentration > 20 mgll (Figure 2-10c). These

spies may be mtricted to bigh dcium habitats howevn, the sample sue of these snails was

small and may wt reprisent their full muge of tolemce.

Pcnnak (1989) states that ncarly aU Lymnacidae are confined to waters having neutrai pH

readings (Le., 7.0) or above. Figure 2-lûâ shows that while this was tnie for sorne of the

lymnaeids in this study (i.e., Fossaria goIbona, F. mudicella, Lymnaea utkoenris and Stagnicda

caperata, in kkeepig with th& putabive high calcium tequirement), ail other taxa were found in

acidic waters as well. The CCA results showed the lymnaeid taxa to respond significantly to the environmental variables @ = 0.01) and that these variables account for 6.3% of the variance in taxa presmce at the sites examineû (Figure 2-16). The plot shows few taxa to correspond to any paiticular environmental variable with most appcariag near the origin of the plot. For taxa with larget sample sizes (n > 4), only S. arcticu appears to correspond to lower than average dissolved oxygen but this may be of limited ecological consequaice to an air-breathing snail.

Fady Physidae - The unusual habitat of Physella wrighti separates it hmother members of this family in temperature and conductivity (Figures 2-1 la,c and Figurc 2-1 7). Physa skinneri was found only at relatively low temperatures (Figure 2-1 lc) but given the wide range of habitats describeci for this species in western North America (Taylor 1988), it seems uniilcely that hi@ temperature would be a limiting factor for this species.

Physidae collected in this study wae assumed to retain dependence on atmospheric air.

The three identified taxa at ecological sites were found in habitats of relatively high dissolved oxygen (Figure 2-1 7b) but there may be otber factors that limit them to îhese sites.

Physidae wac not collected hm sites with low conductivity/dcium concentrations

* (Le., < 10.1 mg; Figure 2-1 7c). This suggesta that these physiâs may have a minimum calcium requVement thst would nstrict them to certain habitats widiin their range. P. sknneri was only found at calcium concentration > 20 mg/i although sample size was smdl (n = 4).

The plots in Figure 2-17d suggest that A. elongatu and P. sAinneni may be separated ecologicdy by pH requirements, with A. elongata occurring in acidk and P. siLinneri Occumng in alkaline habitats, whereas the Physella spp. displayed a wide range of tolaana to pH.

The CCA resuits are that thc physids responded sigdicantly to the environmental variables (p = 0.005) and that these vaziables account for 23.6% of the variance in taxa -ce at the sites examinui (Figure 2-17), A. eiongatu comsponded to tower than average pH, which may be an important ecologicai factor for this species. The sample size for P. skinneri and P. wrighti are small, prohibiting the development of a unimodal response, however, the latter is associated with hi& temperature and conductivity in accordance with its apparent ecology.

Family Plinorbidae - Menetus opemtla~swas found at lower water temperatutes (ma.

22.K) than most taxa in diis family (Figure 2-12a). As it was only collecteci hmlarge, permanent water habitats, water temperature may be an ecological factor for this taxon although it may be restricted to these habitats by 0thfactors. Plunorbella binneyi was also found oniy at relatively Iow water temperature but the mal1 sample size (II= 2) is aot representative of its range of toletance.

The minimum dissolveci oxygen levels at which planorbid taxa with sufficient mple size (i.e., n h 4) were found (Figure 2-12b) might be usefbl to idmtify oxygen-dependent and oxygen-independent taxa within this fsniily. ûxygen dependent taxa, found only above 40% saturation, may be GyrauIus pam, Helisoma unceps ancqs, and Menetus opemlaris.

Oxygen-independent taxa, found at lower than 40% saturation, may be G. circumstn*izh*9, G. cm, G. defletus, Promenetus emrmotrr ~X~CUO~CS,Planorbula campesM and Plunorbella subcrenatum.

Menetus opemlaris was found at the lowest measured conductivity/calcium concentrations and is different âom the nmaining taxa, which occilmd in habitats with higha conductivity/calcium lewls. It may be that these planorbids are physiologicaily prohiiited hm inhabithg habitats with very low 14sof calcium and that this may be a limitiag factor in the number of habitats available to them in northern BC.

Planorbula camptris (n = 4) was the only planorbid found in habitats with acidic mean pH (Figure 2-12d). PIanorbula unnigem (n = l), Plunorbella binneyi (n = 2). and perhaps

Gyraulus ctista (only coiicdtd at pH 2 6.85; n = 4) were found in alkaline conditions. Ali of these taxa have smdl sample sizes.

The CCA results indicate that the planorbids tesponded signdicantly to the environmental variables (p = 0.005) and that these variables account for 8.8% of the variance in taxa presence at the sites examineci (Figure 2-18). However, none of the taxa with large sample sizes appeared to associate with eavitonmental variables of particular importance to their ecology as assesseci from the range plots.

Family Ancytldre - The range of water temperature show in Figure 2-9a suggests that

Fedsia porallelus can tolerate relatively high water temperatures (Le. > 25T).

F. porallelus was not collected hmhabitats of extremely low dissolved oxygen (Figure

2-9b). At sites whae oxygen levels wae < SWh, it was generally collected hmthe undersides of lily pads where the dissolved oxygen satunition may have been higher than in the near-shore water where measuenients were taken. It may be that F. purallelus selects an appropriate minohabitat withUi a water body to ensim an dequate supply of oxygen suggesting that it may be oxygendepcndcnt.

The low minimum level of conductivity/dcim concentration (1.7 mgll) mdfor F.

L porallelw (Figure 2-9c) indicates that the level of dissolvcd calcium in the wata is probably not a limiting factor in the distribution of this taxa in northern BC.

Pd(1989) identified i? proIlelus as exceptional among khwater gastropods in having bdgrecordcd hmpH ranging fiom 6.0 to 8.4. h this study, F. parellelus was found at pH ranging hm525 to 8.75 (Figun 2-9d), an evm wids range than ddbedpreviously. This suggests thrit in all but the most extrcme habitats, pH would probably not be limiting factor in the distribution of this species in northem BC.

Three families wac iacluded in the CCA analysis that incldes F. parallelus, as descni for Valvatidae (Figure 2-15). F. pomllelus OCCUIS on the plot most ciosely conesponding to lower than average conductivity. As F. parallelus displayed no minimum tolenmce for conductivity/ calcium concentration (Figure 2-W), this factor may be of limited ecological importance to this species in northern BC.

Fady Margwidferidr and Unionidae - In Cda, Margaritifnidae are always found in running streams (Clarke 1981). Unionidae are found in both lotic and hichabitats (Clarke

1981), but Anodonta kennerlyi was found only in lakes in northem BC. The temperature of the habitats of these two mussels differed significantly (Table 2-7) with the ruMing water habitat of

M. falcuta being signincantly colder (Figure 2- l3a).

Both musse1 species wmcollected in habitats of relatively hi@ dissolved oxygen saturation (Figure 2-13b). However, the resuits of a study on another Anodonta species, A. grondis, fowd it to be oxygen-independent (Lewis 1984). If this is also the case for A. kennerlyi, it is not consistent with the hdings of diis study.

A. kennerbi was collected hmhabitats with the lowest level of ccndudivity/calcium concentration memureci in this shidy (Figure 2-13c). The higher lm1 measured for M. falcata may be characteristic of northem Pacific drainage nvns or M. falcuta may be restricted to stnams proVidin8 this minimum lml.

While Pd(1989) states thaî mcmbers of the subfemily Andonrinue, wbich includes

A. knnerlyi, are rarely found in adwaters, McMahon (1991) states that member of the Family

Unionidee can grow and nproduce ova a pH range of 5.6 to 8.3, with a pH of leas than 4.7 to

5.0 being the absolute lowa Mt. In this stuîy, A. kenneri'' was coiîected in waters where the pH ranged hm 5.25 to 8.55 (Figure 2-13d), which concm nesonably closely to the range indicated by McMahon (1991) for the Unionidae in grnaal. M./acata was found within a more limitecl range of pH but was found in both acidic and aikaline conditions.

CCA dysisof M. falcata and A. kennerlyi quired combination with otha fnshwata bivalves (Table 2-1). The resuits show that these bivalves did not respond significantly to the environmental variables @ = 0.48), and accounted for only S. 1% of the variance in taxa presence at the sites examined (Figure 2-19). However, the plot shows M. falccrta to correspond to lower than average temperature and A. kennedyi to correspond to higher than average dissolved oxygen, which concur with ecological information exûacted fiom the range plots.

Fady Sphrerlidae - Genera Sphaerium and Musculiiuni - The plots in Figure 2-13a show that Sphaerium and Mt(sctl1iurn species collected more than once were found in habitats of relatively high temperature (> 25°C) suggesting that high water temperature may not be a limiting factor for these taxa in northem BC.

Acçording to Burky (1983), Sphaerium and Mwcuiiun spies are oxygen-dependent. in this study, Sphaerium and Mùsctliium @es wae fouad in some habitats of low oxygen (23%;

Figure 2-13b), but they were neva collected hwn habitats of extremely low dissolved oxygen

(as compare to some Pisidium species Figure 2-14b) and the means are skeweù to the high end of the range. Thus, these findings gendly concur with the oxygen-dependence designation, which may be a limiting factor in the distribution of Spherium and Mwculium species in northern BC.

Sphoeriwn simile was the only species in this grwp with a sample size > 1 (n = 8) that was found at relatively high conductivityIcalcium concentration levels (Figure 2-L3c). This

suggcsts that this species may have a bigha calcium requirement ad, therefore, be more restricted in distribution.

Accordhg to Pennalr (1989) and McMahon (Ml), some sphaeniâs spacies are relatively

insensitive to pH and an cornmon in lakes having a pH as low as 6.0. Sphaerium nitiùum, and

both Mt(scu1ium species were collected hmboth acidic and altaliue conditions, with pH as low

as 5.25 (Figure 2-13d). S. simile was not found at low pH and its putative higher calcium requirement may lirnit it to habitats of higher pH.

The CCA results shows that the bivalves in Gmup 5 did not respoad significantly to the environmental variables measured @ = 0.48) and accountd for only 5.1 % of the variance in taxa presence at the sites exarnined (Figure 2-19). This is also the case if the freshwater mussels are removed fiom the anaiysis (p = 0.62 and 6.3% of the variance in taxa presence at the sites examined explainad). Al1 Sphaerium and Musc1(1ium species with sample size >l appeared near the origin of the plot.

Famiiy Sphaerium - Genin Pisidium - Most species of Pisidh that were collected more thaa once were founâ in habitats wke the water temperature was >25T indimting that high temperature may not be a limiting factor for most Pisidium species in noithem BC (Figure 2-

14a). The exceptions wmP. conventw, which is a coid water species (Clarke 1981), and P. idahoense which was oniy coliectd hmlaices, rivas and streams where the temperature was generally lower than in smaller, more ephemerai habitats.

The minimum dissolved oxygen leveis at which Pkidim species with sufficient sample size (i.e., n 2 6) were found (Figun 2-14b) might be usehl to identi@ oxygendependent and oxygai-independent taxa within this gaius. Oxygen-independent species, found at < 40% oxygen saîumtion, may be P. casertonum, P. compresmm, P. femgineum, P. milivn adP. ventricomrnr. Al1 others were found at oxygen satwations M%,and so may be oxygendependent. Thus, the level of dissolved oxygen in a habitat may be a factor in detemiining the distribution of some Pisidium species in northem BC.

Pisidium species ~eezlledto vary greatly in theu minimum quirements for calcium with

only P. casertanum, P. wtiabile and P. ventricomm fou& at the lowest levels mdin îhis

study (Figure 2-Mc). It may be that many Pisidiwn species are dctedto habitats supplying

th& minimum calcium requirements. McMahon (1991) states that ambient pH does not greatly limit the distribution of freshwater bivalves and that some sphaeriids species are relatively insensitive to pH. However, in this study, mernbers of the genus Pisidium were more commonly collected ftom habitats of neutral to alkaline pH (Figure 2-144 than were most of the other groups of freshwater molluscs examined. This may be due to their putative relatively hi& calcium requirements as mentioned above.

The CCA results were that the Pisidium spies did not respond significantly to the environmental variables (p = 0.225) and accounted for only 3.7% of the variance in taxa presmce at the sites examined (Figure 2-20). The CCA plot shows that most species tended to occur near the origin and to correspond to a combination of variables.

Summary

Fi@-five taxa of freshwater molluscs are now recorded from northm BC comprishg two prosobranch snails, 30 pulmonate snails, two mussels and 21 clams. The relatively low number of prosobmchs and mussels fond is probably because of their limiteci abilities to disperse due to their stcwtopic nahm end restrictive nproductive chmcteiistics.

Forty-nine of these 55 taxa were collected almg with ecological information. The distribution patterns and ecological factors that rnay be important in determining the ment distriions of these 49 taxa an summarized in Table 2-8. Only Sphuerium rhomboidewn appears to have a distribution that may be limited by climate. Lym~eaatkaensis appears to be a

Bering Refuge species and Meneiirs opemluris, Planorbella binneyi, Anodonta kenneri'' and

Murgarinijiera folcuta appear to be Pacific Refuge species. The rnost apparent Mississippi

Refuge species are those that appear to have had their migration halted by the geographic barria of the Rocky Mountains. These are Fmsaria galbuna, Stugnicola cuperata and Plunorbula annigera. The hot spMgs sd,Physellu mghti, may have dvedgiaciation and is known

Table 2-8 (cont.). Summary of the distribution and ecology of the freshwater molluscs fiom ecological sites in northem British Columbia. n = number of sites. Uncornmon = 5 10, common = 1 I - 50, and very wmmon = > 50 occurrences. Fimîiy Plinorbidae (continucd) Distribution Eaologkal Facton Relrted to Distribution Planorhla campfris in = 4) uncornmon; widespread oxygen-independent; minimum 12.1 mg/l calcium; acidic mean pH Helisoma anceps anceps (n = 7) uncommon; widespread oxygendependent; minimum 16.6 mR/1 calcium Planorhellu binneyi (n = 2) uncornmon; Pacific Ref'uge insufficient sample size 1 PlanorbeIIa subcrenafa (n = 35) cornmon; w idespread oxygen-independent; minimum 2.7 mR/I calcium Fady Ancylidrt 1 FerriWu paruIIelus (n = 23) 1 common; widespread 1 oxygendependent: minimum 1.7 mg/l calcium 1 Char BivaMa FadvMaigliritiferidae ~&ifererofa~cuta(n = 4) 1 uncommon; Pacific RefuRe 1 oxygen use type unhiown; minimum 8.8 mdl calcium 1 Fady Un&d&t 1 Anodon~akennerlyi (n = 12) 1 common; Pacific Rehe 1 oxygen use type unhiown; minimum 1.7 mplL calcium 1 @ Fady Spbitrüdit Sphaenbm nitidum (n = 14) çommon; widespread oxy~endependent; minimum 1.6 mgll calcium Sphaetîum rhomboideum (n = 1) uncommon; south area insufficient sarnple size; possible climatic restriction Sphaenitm simile (n = 8) uncornmon; widespfead oxygendependent; minimum 16.6 mg/( calcium

Sphaenum sfriatinm (n = 1) unwmmon; south ares . insufficient--- sample - - - size Musculium lacusire (n = 33) cornmon; widesprd- oxygendependent; minimum 1.7 mg/I calcium Musculium securis (n = 36) conunon; widespread oxy)ien4ependent; minimum 1.7 mg/l calcium Pisidium caserIanurn (n = 6 1) cornmon; widespread oxygen-independent; minimum 1-7 m&/lcalcium Pisidium compressum (n = 20) wmmon; widespread oxygen-dependent; minimum 12.8 mg/l calcium Pisidium convenîus (n = 6) uncornmon; widespread oxygen-independent; minimum 12.8 mgIl calcium; alkaline pH only Pisidium filfax (n = 2) uncornmon; souhast ara insufficient sample size Pisidiumfemgineum (n = 19) çomnmn; widespread oxygen-independent minimum 9.6 mg/l calcium Pisidium idahoease (n = 12) cornmon; widespread oxypdependent; minimum 12.8 mp/l calcium; alkaline pH only Pisidium insigne (n = 1) uncornmon; west area insuf'ficient sample size Pisidiurn li&eborgi (n = 13) cofnmon; widespread oxygendependent; minimum 10.1 mg/l calcium; alkaline pH only Pisidium milium (n = 17) cornmon; widespread oxygen-independent; minimum 8.6 mR/1 calcium

Pisidium nitidum (n = 9) unammon; widespread oxygen-dependent;]- calcium ;alkaline pH only ------Pisidium punctatum (n = 1) uncornmon; east area indiciait sample size Pisidium variabile (n = 36) cornmon; widespread oxygendependdent; minimum 1.6 mgll calcium Pisidium ventricosurn (n = 23) common; widespread oxygen-independent minimum 1.6 mp/l calcium globally only hmone location in northem BC (Te and Clarke 1985).

Water temperature appears to be the least important of the four environmental variables measund, in determinhg molluscan distribution. Taxa found at low water temperatures were generally found in large, perainial water bodies and these species may be restncteù to thae habitats for other reasons.

Five of the nine families of fieshwater molluscs in northem BC could be categorized as either oxygm-independent or oxygen-dependent (Table 2-8). Oxygen-independent taxa were generally found more ofken as they rnay be able to sunive in a wider range of habitats than can the oxygen-dependent taxa, which are obvMusly testricteci to well-oxygenated habitats.

Russell-Hunter (1978) categorized fnshwater molluscs in Britain according to th& calcium requirements (Table 2-9). nie 49 taxa found at the eoological sites in this study were sirnilarly categorized and compared to the British categones (Table 2-9).

Table 2-9. Proportions of hhwater molluscs hmecological sites in northem British Columbia as cornparcd to the proportions of khwater molluscs in Britain in relation to dissolved calcium content as desaiby Russell-Hunter (1 978). Northem British Columbia hhwater molluacs used in this cornparison were those with n >2 plus the endemic species, Physeh w@i. Minimum ddum Nu-r of taxa and Number of tua rnd m@remcit p~rewitof t0bl-8 hi p~r~t!ltof t0td mi hl northern BC Britrin I Low:c3 11 27% 7 11%

1 Moderate: NOto 20 1 13 32% 1 6 10% 1 Calciphilic: > 20 6 14% 30 48% Totals 41 lW! 62 lW!

This cornparison shows that northem BC has far fewer dciphiîic molluscs than does

Bntain (i.e., 14% vs. 48%, reqcdvely). etively).s is not a hction of a limited nmber of hi&- calcium concentration sites, as -75% of the ecologicai sites examinecl had calcium concentrations 2 20 mg/l (Table A-1). The propodon of molluscs found in habitats with intemiediate (Le., 3 to 10 mg)calcium concentration was similar between the two areas (27% vs. 3 l%, respectively for BC and Britain), but BC had a much higher proportion of molluscs able to tolerate low (i.e., <3 mgA; 27% vs. 1 1%, respectively), and moderate (i.e., > 10 to 20 mgl;

32% vs. 10°h, respectively) calcium concentration. Thus, BC has a higher proportion of non- calciphilic taxa than does Britain (86% vs. 52%, respectively). The high proportion of non- calciphilic taxa in the geologically young habitats of northem BC may be indicative of the ability of these more euryoecic taxa to be successfully passively dispersed and inhabit new areas.

Many fieshwata molluscs were fond in both aikaline and acidic habitats but most had an alkaline mean pH (> 7). The exceptions having acidic mean pH (< 7) were AcroIox1(s coloradensis (n = 7). Aplsro elongata (n = 4), and Planorbulo campesrris (n = 4). Molluscs fomd only in aikaline habitats (2 6.85) were Fossaria galbuna (n = 4), F. modicella (n = 8).

G'aulw cristu (n = 4), Pisidiun conventus (n = 61, P. idohoense (n = 12). P. lilQebow (n = 13) and P. nitidùm (n = 9), which may be linked to their putative high calcium quir;ieinents. Many of these taxa had relatively mal1 sample sizes. This highlights the conmdnim as to wheâher uncornmon taxa appear to have limited ranges ôecause they are collccted less oflen or are they collected las often because they bave limited ranges.

This study hypothesized that the hshwater molluscs in northem BC would be randody distributai. Howcver, of the 49 taxa of molluscs found at the ecologicai sites, one species (2%) displayed distribution consistent with the climatic-limitation hypothesis in that it reacbed the northermost limit of its range in noabcm BC, and nine species (4 Pacific, 1 Bering and 3

Mississippi plus P. wrighn'; 18%) displayed distributions consistent with glacial phenornena

The three Mississippi refuge species (6%) appear to have been unable to overcome the gcographic barriet of the RocLy iMountains.

Hennan (1974) cites several authors who found little or no correlation bawcen species 63 presencehbsence and water chemisüy. The results of this study suggest otherwise for 36 of the

40 taxa coliected fiom more than two ecological sites plus the endemic species P. wnghti-

Specifically, dissolved oxygca, conductivity/dcium concentration and pH appear to affect the distributions of 14, 30 and 10 taxa, respectively, with a combination of these factors evident for

some taxa. in the five families of hhwater molluscs whae dissolved oxygen use could be

examined, 27 taxa were collected more than twice at ecological sites. Of these, 14 taxa (52%)

appeared to be oxygen-dependent and so restricted to welloxygenated habitats. Of the 40 taxa

collected from more than two ecological sites plus P. wrighti, 30 taxa (75%) were collected at

sites where the calcium concentration was > 3 mgfl, and 6 of these (15%) were found only in

habitats with calcium concentration 2 20 mg. Of these same 40 taxa, ody thm (7%) had an

acidic mean pH and seven taxa (17%) appeerrd to be restricted to habitats of alkaline conditions.

The taxa Stagnicola arctica. Pltanorbella subctenata, Andonta kenneriyi, Pisidium casertanwn

and P. ventricosuni showed no discernable rrspoir9es to any of the environmental variables measured.

Climate, history and geograpby appear to affect the distribution of some freshwater

molluscs, and physico-chernical fadors may also be important deteminants of the habitats

occupied by msny taxa in northm BC. Realistically, it is likely that combinations of many

factors have shaped îhe psent distnaition and ccology of the âeshwater moiiuscs of northem

British Columbia CHAPTER 3 - COMPARISON OF CONTEMPORARY AND HISTORIC COLLECTIONS OF FRESHWATER MOLLUSCS AS A MEANS OF ASSESSING ENVIRONMENTAL QUALITY.

Introduction

Assessments of the consmation status of organisms are important guides for the allocation of conservation tesources and are best made when based on detailed historical information. ûne of the key uses of historical information is to help calibrate present expedations regatding the productivity, diversity, and stability of natural systems upon which himians depend (Stecdman et al. 1996). Most available historic information on organisms is in the fom of taxonomic dections. As changes in cornmunity structure are generally accepted as indicative of changes in environmental quality (Noms and Georges 1993), it should be possible to examine temporal changes to habitats by cornparhg contemporary and histone taxonomic collections (Steedman et al. 1996, McCarthy 1998).

Contemporary and historic collections of Wwater molluscs have been made in northem BC. Much of the historic information dates to collections made by Dr. A. H. Clarke and assistants for the National Musermis of Caaada (now the Canadian Museum of Nature) during the summers of 1972 and 1973 (Clarke 1972, 1973a). May changes have occurred in

northem BC sina that tirne. For example, the human population in the six regionai districts that

are entkely or partially within northern BC iudby 48% in the 25 yean hm197 1 to 19%

(Figure 3-1). As the eamomy of northem BC is basai pnmanly on natural murce utilkation,

it can be EISSU~~that the indhuaim population nflects an incnase in the use of northem

rmiaces, especially forests. Indpopulation and murce use may have impacted aquatic

ecosystems in a manner reflected in tanporal changes in hhwater moliusc cornmunities. A

direct comparison of cornmunitics ushg historic (i.e., 1972f1973) and contemporary (i.e., 1997)

data may give an indication of histone and potential future impacts on.aquatic ecosystems~

65 District Intercensal

1996 %Change

1,470 1,450 - 1% Fort NelsodLiard and Peace River

KitimaVStikine 37,326 45,457 +22%

59 - Ft NelsoniLiard 49 - KitimatlStikinc 55 - PtaccRiver 174,301 258,506 +48%

Figure 3- 1. Regional Districts of British Columbia and intercensal human population estirnates in 197 1 and 1996 for regional disüicts within northem British Columbia with percent change during this tirne @ode (From British Columbia Statistics, Minisay of Finance and Cofporate Relations, Victoria, BC.)

Cornparisons of floral and faunal communîty composition may provide important insights into environmciltd quaiity and similarity indices can be irPed to quanti@ smiilarities between cornmunitics (Spellerberg 1991). Mamasures, such as functional-fecdmg guiids, can @de insight into the coology and f'unctioning of the acosystems by elucidating diffaences in food aquisition (Rdand Jackson 1993). Changes in the relative proportions of fceding guilds are gendy intaprettd as "stress" to the community (Lenat and Barbour 1993) and these may provide a memm of the natural aid mtûmpogenicaily driven changes in quatic ecosystems

(Cummings 1993). This approach is ohused in snidies of aquatic iasect larvae in which species are categorized by th& eating habits as shredders, gathering collectors, filtering coUectors, saapers, predators and plant pincas (Cmmins 1993). The use of fkhwater molluscs in water quality studies has la@ bchiad that of other aquatic organisms such as insects (Strayer 19998). Howevcf, an dogmgdd 8pp108ch may be possible for âeshwater molluscs, which can be 8SSigned to four fceding guiids based on th& generalized method of 66 food acquisition. These guilds are: (1) grazers - gasmpods are generaiiy grazas on mfwuchs

(organisms fomiing a living film on quatic substrats) that grow on solid surfaces in quatic habitats (Brown 199 1); (2) suspension feeders - mussels, and clams of the genm Sphamùm and

Murculium, may remain relatively sedentary in sofi sediments, obtaining food by dniwing sumwiding wata over their ciliated gills (McMahon 1991); (3) deposit fesders - clams of the genera Sphaen'um and Mwculium may supplement suspension feeding by using their inhalant

siphon to draw in food hmthe sediment dace(Way 1989); and (4) infaunal feeders - clams

of the genus Pisidium actively crawl thugh soft substrates, feeding on organic material that

becornes available through their bmwing activities (Idpez and Holopainen, 1987).

Materials and Methods

Histonc and contemporary species lists and person-hours spent on collection at

appropriate sites were taken hmLee and Ackaman (1999a). Contemporary collections were

made by the methods descn'bed in Chapter 2.

Sonason's Commmity Cornparison Index, a binary (Le. pnsencelabsence) community

similarity index, was used to quanti@ diffcrrmces baween the spocies assemblages found

contemporarily and histoncally at the samc sites. The fornula for this Mex is:

where C is the index of similarity, w is the numba of species eommon to both samples, A is the

nmbm of species in sample one, and B is the number of mes in sample two. The scores are

multiplied by 100 to give a perceat de. A vaiue of lOWI indiates complete similarity and a

value of OO/o imlicates complete dissimilarîty between srnnples (Spellabag 1991).

The simüarity of contempomy and histonc mollusc cornmunity sûucture was also

examined by cluster dysiswith Statistica 5.1 software (StatSoft, hic. 1997). Species lists were categorized according to feading guild. As species of the gmera

. Sphoerium and Mumlium are believed to both suspension and deposit feed (My 1989), these

species were divided evenly between the two groups.

Resuits

There were sixteen sites in northem BC for which historic and contemporary collections

of freshwater molluscs could be cumped (Table 3-1). Tables 3-1 and 3-2 show that at al1 but

the single species sites, contempomy collections contained more spacies than did historic ones.

At two sites, the same single species was collected resulting in similarity indices of 10%. At

another two sites, the contanporary and historic collections contained dissimilar species

dting in similarity indices of W. For the remahhg 12 sites, the cornmunit- similarity

indices were quite low (Table 3-2) with results exded50% for only three sites.

Time-search effort was generally bigher in the contcmporary study (Table 3-2) during

which 29.8 hom wmspent on collection whneas the total historic collection tirne was 18.7

hom. A total of 126 collections of taxa wen mrded contemporarily compareâ to 53 recorded

histoncally. Thus, the conternpotary sndy cxpded 1.6 times more seanh-effort resulting in

2.4 times as many collections of taxa

Clusta analysis producal a vatical ideplot (Figun 3-2) that resulteû in only three of

the contemporary and histonc sitepairs forming direct pups (indicated by "*" on Figure 3-2). Two of these were single specia sites (Alpha Stream - N1108lCN1023 and Lakelse River -

N1083/CN1022), which join a-a Euclidan distance of O as the communities were identical and

so had sMUla&y indices of lWh, and the third was Azouzetta Lake ('N1008/CN1013), which

had the next highest similarity index of 67%. In genaal, the cluster analysis failed to identify

pattems among or between sites.

The categorization of funaoaai feeding gups (Table 3-3) showd that contemporary Table 3- 1. Species lis& for historical and wntemporary collections maâe at sites in northem British Columbia. "*" indicates collections that were made within the same wat& body but not et the same sites. Taxa found in both years are indicated in bold.

1. McLdLake 4. Dtrse Lake* -N lOû3 (1997) N 1068 (1 997) CN 1005 (1 972) Val vata sincera sinceria Vilvafalewisi lewisi Lymnaea atkuensis S~&o&eb&s Vaivata sincera sincera ShvgnkoIri adca PhjwUa sp. Lymnaeu a!kaengJS Pirysi jennessi jennessi GyauJus circumrtriufw Slognkola urcisca Gyrawlrrs wmiccuCar3s Helbma uncep ancep Stagnrgcoluelodes Pisidium case~anum PCarior&Ua subc~~11O1O Physa skinneri Fisidiwm vuriabue Ferrissici parallela Gyravfws ci~~umsirtaîns Aiirdbnta karre~ midvurn caseamum Sphaeriirm simile Pisidiurn idahwme Piskiium compressum . Pisidium mihm Pisidium nitidum lvki&nmHarkrbüc - 5. Eddonttnrjon Lake* N1073 (1997) CN 1004 (1 972) Valvata lewisi lewhi Gyrauius ~crmicnîàrrS Stugnicola elodes Sphaenum nitidum Gy~y~nIàiscku~lsîriatvs PLsMum c4sctfanum PWdinm caserfonum Pisidium compressum Plskuum idaliroeirse Pisidium idphmnse Pisidium vuriabile Pisidium lillieborgi I -3. Tate Creek 6. Lakelse River N1016 (1997) CN1014 (1972) N1083 (1997) CN1022 (1973) Stagnicola caperata Gwwcirmrmr~ri~~ttrs Margadh#ieru ficata Margarili/.erafalcata Physellu sp. Mweulium lacustre Sphetium simile PLsidiurn nitihm Pisidium compressum Table 3-1 (wnt.). Species lists for historical and contemporary collections made at sites in northem British Columbia. "*" indicates collections bat were made within the same water body but not et the same sites. Taxa found in both years are indicated in bold.

-7. Suley Lake 9. Stelirko River -NI091 (1997) NI 102 (1997) I Valvata sincera sincera VikwJsi kwisi Ly~nnaeastagnalis oppressa Valvata sincera sincera PhpuII sp Stagnicola elodes Gyraulus circumtriutus Physelia sp. Pnmenenrs exacuous exacuous Gyraulus circumsfn'alus Pfunorbellasubcre~tu Promeneîw aacuous exacuous FerrbsJripral%& Menetus operculatis Musculium lacustre Musculium lacustre Mkwulium securis Pisidium casertanum Pisidium comprmsum Pisidium compressum Pisidium conventus 8. hktrLake Pisulium idlahoense -NI100 (1997) Valvatusincera sincera 10. rlougb of Nechako River Physella sp, N1103 (1997) CN1018 (11973) Acroloxus coloradenris Valvata lewisi lewisi Valvata sincera Gyraulus deflectw Stagnicola arctica Stagnicola elodes Promeneîus aacuous examour Physella sp. Planorbella subcrenata Menetus opercularis Gyroulus circumtriatus Anodunfu kennerlyi Fedsia parallela Promenetus exacuous exacuous Musculium lacustre A8~orib1)Ra~IIIIC~~~ Pisidium caserfanum Musculium securis Pisidiumfemgineum 11. Alpha Stream - Liard River Hotsprings NI108 (1997) 1 CN 1023 (1 973)

12. Warm Swrmp - Liard River Hotsprin~s NI 109 (1997) CN 1023 ( 1 973) Cyraulus ciniuimstr&tus Physa virginea Pisidium caserfanum GyrauIus cir~umshkrtus Table 3-1 (wnt.).- Species- lists for historical and contempoiary collections made at sites in northern British Columbia. "*" indicates collections that were made within the sarne water body but not at the same sites. Taxa found in both years are indicated in bold.

-13. Stuart Lake* -N1105 (1997) CNlûûû (1972) NO108 (1997) CN1017 (1973) Valvata lewisi lewisi S~rrgudcohe&&s Planorbella su bcrenata Valvata sincera Valvata sincera sinceru Gyraulup vennicularis Fertissia prallela Physella propinqua Lymnaea stagnalis appressa Prorne~~etusexacuous ÇIC~CYOYS Sphaedum simi& PlanorbeIIu binneyi Sîkagrrkokr ews Milsculium îranmersum Musculium lacustre Anodonta kennerlyi Physella sp. Pisidium compressum Musculium securis Sphuerium similc Gyraulus circumtriatrrs Pisidium nitidum Pisidium casertanum Ptoncnetus Cx~cyOyscracyoyb Pisidium variabile Pisidium compressum Pianorbula campestris Arrodonta kennedyi 16. Summit Lake Musnrlium lacustre NO1 13 (1997) Pisidium casertanum Valvafasincera sincera

- -- Physella sp. 14. ~ide~Lake Helisoma anceps anceps NI 107 (lW7) CNlOI5 (1073) Planorbella subcrenata Vulvata lewisi lewisi Acmkus c&ra&nsis Gymulus circunis!ria!us Ljmrioea stagnalis appressu Physu sp. GyrauIus ~NUS S!ognicola catascopium Promeneha exocuous exaçuous catascopium Ferrissia parallela Physella sp. Anodontu knnedyi Actofa~wscoloradcnsis Sphaerium simile Gvraulus dejlctus Musculium securis Promenietus exocuorrs exacwus Pisidium caser!unum Helisoma anceps anceps Pisidium milium Planorbella subcrenata F'whsiaparallela Sphaeriirm simile Sphaenùm striatinum Musculium securis Pikidiirm cîasertunum Pisidium compressum Cr) -Cr)

-rn

-m

œ -m 2

3w -*M e 3 -L

C -t

I C -C4

rC L -f!

Ci -C

collections comprised 62% vas, 10% suspension feeders, 6% deposit fders and 22% infaunal feeders, while the histonc sites had 56% grazers, 16% suspension feeders, 5% deposit fders and 23% infaunal feeders. In only one multiple species site-pair âid the proportion of hctional feeûing groups remain the same (Nlû68/CN1005). The contemporary ccllections found new f'unctional-feeding groups at nine of the 16 sites (N 1003, NlO9 1, N1100, N 1 102,

N 1103, N 1009, N 1 107, NO 1 08 and NO 1 13), whereas fùnctional-feeding groups had been lost at two sites (N 1073 and N 1 103).

Discussion

The results of both the similarity indices and the cluster analysis showed very low levels of similarity between the contemporary and historical freshwater mollusc collections. Low codity similarity indices can be indicative of stress, with lower diversity occdg in süesseù communities (Noms and Georges 1993). Given the asmmed inmase in natural fesource use in noithem BC during the last 25 years (1972 - 1997), the habitat impvement mggested by higher contemporary diversity seems unlikely. Possible alternative interpretations of the data are:

1. Divemity hm increucd nitpdy u fmhwrter moiiuscs continue to be pusivdy dlrpeMd hto northern BC.

Most northern BC aquatic habitats have probably been in place for hundreds to thous8tlds of years aud it seems imlilrely that such a large amount of immigration would have occurred in the 25 year intcrval examined hm.

2. Chtechange.

Average annuai temperatures in the Prince George ara of northem BC have typically been above the 50 year mean of the records since about the mid-1970's (Petticrew et al. 1999).

Freshwata molluscs historidy restricted hmnorthem climes by life history repuVernenu may have been able to move northwards with the advent of a wamiing trend in northem BC.

Contemporary collections at the 16 sites found 13 taxa not recordecl by Clarke fiom these same sites (Table 3-4). However, Clarke's collections may have been incomplet el y pmessed

(sebelow), and the distribution maps published by Clarke (198 1) are reasonably consistent with current known distribution for nine of these taxa (Table 34). Of remaining four taxa, Vizivata sincera sinceru, MwcuIium semd and Pisidium milium are al1 recorded from the Northwest

Territories (Clarke 198 1) so it is unlikely their being aewly recorded frwi mrthem BC has been due to a wanning climate trend. The absence of previous mrds for the fourth taxa, Femssia puralIeIus, may be due to collection technique (see below) as contemporary collections of this taxa were most ofien made hmthe bottoms of lily pads accessed ody by enterhg the water in chest waders. Thus, thete are no apparent incnases in diversity that can be readily linked to climate change in aoRhern BC.

Table 3-4. List of taxa recordcd contemporarily but not historically hmthe sixteen sites cumpared in northem British Columbia with historid distniution as ncorded by Clarke (198 1).

Tua Distribution recordcd by Clarke (1981) Valvata sillcera sincera Not recordcd in nortbem BC Stugnicola catascopium cutascopiutn Mappal consisteatly with prescrit known distniution Stagnicola caprata Mappcd consistently with pmcat known distri'bution Gyrault~~de/fectus Mmconsistdy with prisait lmown distniution GyrauIw panw Mapped consistcstly with prcseat known distniution Menetw opemlaris Mappai comistcnsly with prrse~thown distribution Plunorbula campest& Mappcd consistentiy with pment hown distnbution Ferrissi0 parallelus Not recordad in danBC Sphenenumsniotiiiun Mapped consistcntly with prisent hown distniution Mwculium securis 1 Not rccorded in mhcm BC - I Pisidium conventus Mappai consistentîy with pnsept kuown distniution

I Pisidium miIium I ~otrccorcîed in northern BC I 3. SampIing biis.

Bias is the magnitude and direction of the tendency to measure something other than was intended (Eisenhart 1968). Estimates of community diversity hmsamples are always biased

(Green 1979) but attempts can be made to rninimize bias by:

(a) standardking operutor expertise, or ensuring that results are intepreted similarly by experts or novices. Booth and Dussart (L998) found that the number of species found in searches for temstrial macromolluscs varied significantly with operator experience. Fwther, rapid bioassessment protocols of aquatic habitats r#luire that field crews with varying degrees of expertise be able to accomplish similar levels of identification in grouping analyses of aquatic macroinvertebrates (Cmmins 1993).

(b) using standrrrd collection techniques - Dorazio (1999) found that in meys of fteshwater mussels the composition and relative abundance of species differed significanîiy with collection method. If Clarke's ooliection techniques diff'ered hm that used in the contemporary study

(e.g., rnay have been maâe only hmshore), this could account for the lessa number of species that were gendlycollecteù historical1y.

(c) eflort eapended - the probability of eacountcring a common species is probably good regarâless of effort, whereas the probability of encounterhg a rare species inmsignifimtly with additional effort (MetcalfeSmith et al. 1997). Thus, the number of species collected hma given site is related to the effort apcllded. As show in Taôle 3-2, more time was of?en spait making the contemporary collections than was spent historically. The nsult was that contemporary study expended 1.6 times as much scarch-effort resulting in 2.4 times as many collectiom. Collection effort expended is an important component of community comparisons.

4. Inmmpletc procesiing and uchhring of ail cet ion^.

Wbile Clarke's field notes (Clarke 1972, 19733 did not always incluâe species lists, some of the taxa that he noted arc not coafirmed by voucha specimens at the Canadan Museum

77 of Nature (CMN). Examples of these are listed in Table 3-5. Important collections not conhed by voucher specirnens are Acroloms coloradensis and Margarififerafalcata, which had previously been rrcorded hmsingle locations in northem BC. In the BC collections at the

CMN' there are 75 lots of unidentifid collections hmthe Family Lymnaeidae and 72 lots hm the Family Physidae (Lee and Ackennan 1998a). Thus, Clarke's collections from northem BC may bave been incompleteiy processed and archived.

Table 3-5. Species noted by Clarke (1972, 1973a) as occurring at sites listed that are not confirmed by voucher specimens at the Canadian Museum of Nature. 1 site 1 Coiledons noted in field notes not 1 1 verified by CNM voucher specimens 1 1 CN 1O 11 - Summit Lake Physa sp.; Helisonra sp.; Femissia sp. CN 1012 - McLeod Lake Valvata sp. CN 10 15 - Purden Lake Acrofoxus colomdensis; Physa sp. CN1022 - Lakelse River 1 Margariti/erafalcutu

Sorenson's CommUIUty Cornparison Index pmvided little information about the nature of the temporal change in community structure. While the index was generally less than IO%, indicating diffaiag divmity, this was just as eady sem by a count of the total number of species. According to Poole (1974)' a count of species is the ody truiy objective measure of diversity. Exmination of species lists is aiso the only means by which to detamine changes in feading @&. Pielou (1969) states that fahionable trends such as the use of diversity indices

"have led to false analogies that produce no noticeable advance in ecological understanding".

Based on the dtsof this study, I agree with Green's (1979) statemént that '?he use of derived indices as indicators of environmentai quality in some general sense is not an approach about which 1am eathusiastic".

Cluster dysis was an effective technique for pairing sites that were identical or very similar. However, the clustering of sites of lesser similarity were of limited ecologicai intapretability whm only the vertical icicle plot was examined (Figure 3-2). Again, a direct examination of species Iists pmvided mon nadily interprctable findings.

Feedhg Guilds

There does not appear to be a precedent for the examination of aquatic systems by the proportions of frwhwater mollusc focding guilds. The overall proportion of these guilds remained quite similar during the 25 year inteiival studied (Table 3-3) suggesting no overall change in the types of food resowces available to molluscs. However, when examined individually, 10 of the 16 sites had diffaait guilds present (nine of the contemporary sites had new guilds and two of them lost guilds; Table 3-3). Of the remaining six sites, five had similar proprtions in bth studies but Nl lOS/CN1000 had changed considerably (Table 3-3).

Thetefore, based on change in guild sûucturt, 11 of the 16 sites (69%) appear to have undngone habitat change during the 25-year intaval. While t.smay be the case, other problems related to the historic data discussed above precluâe the possibility of assessing habitat change by

cornparisons of these mords.

Conclusions

nie cornparison of the contcmpomy end histonc collections was expected to have

pmvided some idonnation on the manna in which the increase in human activities in northern

BC ha9 affêcted aquatic coosystems and their mident molluscs. However, the uncertainty

regadhg how the historiai data was collecteci and processeci precludes the possîbility of direct

cornp8risons. The tesolution of rrirospectivc answers to ecologicaî questions wili always be

limited by the eccmcy, extent, and spatial and temporal coverage of historie data (Steedman et

al. 1996). Management practices can only be based on existing idionnation so it is important

thai data be as cornprehemive as possiae so that 8SSeSSments are scimtifidy defensible. In

79 this study, it appears that differences in collection the, perhaps collection technique, and the apparent incomplete processing and cnchiving of historic collections, has limiteù the use of these records in assessing possible environmend change. CHAPTER 4 - THE EFFECTS OF FOREST PRACTICES ON FRESHWATER MOLLUSC HABITAT: A CASE STUDY FROM THE TORPY RIVER WATERSHED IN EASTCENTRAL BRITISH COLUMBIA

Introduction Potential confîicts between fonst practices and presemation of aqwtic habitats are widely recognized. However, these conflicts are difficult to assess or predkt as thae is insufficient evidence on aquatic cornmunity responses to habitat alterations (Newbold et al.

1980). Moreover, the most basic relationships pertaining to forest harvest effects on quatic systems still main theoretical (Miller et al. 1997). While fkeshwater molluscs have unique strengths as water quality monitors (Strayer 1999a), littîe nfmnce has been made to this group as indicators of habitat change such as those that may rdthm forest practices. Available information oAm relates oniy to hshwata mussels and is mecdotal or descriptive rather than based on scientific study. For example, shifts in mussel community composition, declining mussel abundance and local extinction have ôecn attriiutd to, but not pven to be caused by, changes in habitat caused by deforestation and the destruction of ripaian zones (Neves 1992,

Williams et al. 1993, Moms and Co- 19%, Bogan 1998, Box and Mossa 1999).

As the ecology of âcshwater snails and clams is ofien quite diffmnt âwi that of

moîîuscs. Evidmce hmotha Wwater O~@SII~S, mainly aquatic insect Iarvae, shows that whiie species diversity may decrease following timber removal, the abundance of the rrmaining aquaîic insect lame genaally inmases (Newbold et al. 1980, Noel et al. 1986, Carlson et al.

1990, Fore et al. 1996, Stone and Wallace 1998). Given the diffnmas in taxonomy and potaitid respomes, the effectp of fonst pctices on khwater molluscs mains to be

Forest practices aha the natural lmûscape in many ways including the coastnicton of access roads that may result in the mation of wet areas (i.e., lentic or standing water sites). For example, low-lying seepage areas rnay be culverted or cha~eiedinto ditches to avert road flooding. In somc cases, equipment scars may becorne permanent wet areas. When road construction requires a stream to be crossed, a bridge or culvert is installed (Society of Arnerican

Foresters 1984; British Columbia Ministry of Forests 1995a). Culvert installation in lotic

(flowing) sites alters the naturai stream hydraulics by channeling the water through a narrow opening, ofien nsulting in the formation of a pool on the upstream side of the culvert. Mc conditions might also be affacted by the loss or reduction of riparian vegetation, although vegetation rnay be maintained in a riparian reserve zone to mitigate against such impacts

(Society of Arnerican Foresters 1984; British Columbia Ministry of Forests 1998). Increased sedimentation has been associated with complete hber moval in a watershed close to that of the present study (Brownlee et al. 1988). Collsequently, it wouid be reasonable to examine whaha riphan condition affects sedimat dwelhg moîiuscan divdty or abundance.

The Torpy River watershed in east-central British Columbia (BC) provides an opportunity to sccess a wide nnge of forcstry and relatai impacts because of a long history of fomt ptaaices. The uôiquitous khwata clam Pisidhm cusertanlm (maximum 5-mm &el1 length) provides a mode1 species by which to examine seûiment accumulation rcsulting âom fonst praciices as it cm nsdily inhabit newly created aquatic habitais with sdimmt substrates

(pers. obs.) whae it bmws out canals and feeds upon interstitial bacteria (Meier-Bmk 1969,

Lopa and Holopainen 1987). An examination of the local distriiution and abundance of this species, as well as cornparisons of moîîusc coxnrnunity structure, shouid pvide data with which to aswss the effects of fonst practices on freshwater moiiuscs. The resuits of the study would

also be of interest to fomt managers, Spenficaüy with reqect to how roaà building and riparian

conditions crin affêctthe habitat of sediment dwelling stream organisms. Materials and Methods Study Area

The Torpy River watashed is located about 90 km east of Prince George, BC, Canada

(Figure 4-1). This a.is mountainous with an alluvial substrate of clay, sand and gcavel.

Streams are mainly first orda, either spring fed or the result of snow melt and groundwater inputs The forest cover is primarily conifmus dorninated by white spruce (Picea glauca), subalpine fir (Abies lariocarpu), and hemlock (Tsuga spp.). This watershed has a 40-year history of forestry activity (British Columbia Ministry of Forests 199%) and forest practices and the requisite landscape alterations of access road construction and timber ranoval continue. The watershed comprises one large lake (Pass Lake) and thne rivers (West, Upper, and Lower Torpy

Rivets). Thae is limited access to the West Torpy Riva. The Upper Torpy River tlows through very steep temin and initial survey work for bis study found that the fast flowing tniutary stnams and the smunding landscape offd litile âeshwater mollusc habitat. The Lowa

Torpy Riva (LTR) watcrshcd is the focus of this study. The low slope of the lmdscape

------p. Figure 4-1. The Toqy Rim Watcrshed and its location in British Columbia adjacent to the LTR allows for the formation of natural pools in the tributary streams and for the occurrence of other types of water bodies that cm host populations of fiesbwater molluscs. An access road appmximately 47 km long nms parallel to the LTR. This road aossed 1 19 tributary streams and there were 58 adjacent wet areas.

Habitat Classification

Habitats were classified as either Initie or lotic basad on inspections. Lentic habitats, in which the water is not flowing except during rainf'l or snowmelt, were categorized as follows: Water accumulations - low-lying areas adjacent to the road fed by seepage or pund flow that have been culverted to pmait excessive water accumulation hmflooding the road;

Ditches - areas excavated paralle1 to the road to divert seepage or groundwater flow; Ca~aiLÎ- anas adjacent to the road where road building quipmmt had created shallow scars

that kame pnmanently wet or filled with water, and that had characteristic vegetation of

catiails (Typha latifiofiu);

Pook - water bodies < 100 m2 surface area adjacent to the road ftmlting hmroad building

quipment mting deeper scars (up to 0.5 m depth) tbat had become pennanently fïîled with

water but did not have populations of mails; and Ponds - th- were tbrre large ponds (> 0.5 m depth, > 1000 m2 dacema) adjaant to the

road in the LTR watershed that probably aistecl prior to fomt pctices.

AU of the lotic habitats were tri'butary sûcams flowing into the LTR. In these strrams, the instailation of cuivcrts haâ caused pools to fonn on the upstream side of the culverts. These strw wae categorized according to the type of upstnam riparian condition based on forest cova maps producecl by British Columbia Minhtry of Forests (199%) and updated âom observations of more ment activity. Thnie four categories wae: (1) Unlogged - whae the original forest tanained intact; (2) Old Clearcut - where the originel forest adjaceat to the stream ha been removed, but

mfficient tirne had elapsed for some fomt repwth (logged >10 years prior to shidy); (3) New clearcut - where the original forest adjacent to the stream bas been nmoved and no

significant regrowth had occurred (logged 40yem prior to study) and;

(4) Riparian Reserve Zone - where a 20 to 50 meter wide area of intact forest irmnediately

adjacent to a stream was left within a cleamit (adjacent clearcut made 40years prior to

stud y).

Sampling

Suitable sites for molluscs wm considered to be low discharge streams with soft

sediment substrates and dl lentic habitats adjacent to the LTR road. ' Hi@ discharge sites with roc@ substrates were oonsidd non-suitable sites based on preliminary collections withia the area. Ali habitats tbat appead to offer suitable âesbwater mollusc habitat dong the length of the LTR road were assessed for the pmence of molluses. Selected streams, chosen on the bais of downstnam clam densities and upsûeam accessibility, were meyd to ascertain whether populations of clams (P. cusertanum) were prrsent upstream. Pass ~akewas aiso sampled to examine local mo11usc bioâivcrsity.

The presence of molîuscs was assessed with an 18 cm diameter stainless steel mesh net with a nominai pore &e of 8pproximately 1.5 mm, attachai to a broom haadle by hose clamps.

This net was used to sweep vcgctation for mails and to dig into soft sediments for the coilection of clams and sediment mgds. AU moliuscs founâ wae collecteâ, preserved, and idmtified using criteria pfe~catcûin Burch (19758, 1975b, 1989), Clarke (1973b, 1981) and Harington (1%2,1%5).

If sevaal net 58mples (4 to 6 minimum) in soff wdiments yielded at least one clam, the area was sampled qmtitatively with 63.5-mm (2.5-inch) diameter plexiglas coring tubes (ma 0.003 1 rn2). These were pusheû approximately 64 mm into the sediment; a lid was attached to create a vacuum, and the tube was withdrawn with the contents intact. Four replicate cons wm

collected at each site. The content of each core was transferred into a labeled plastic bag and retunied to the laboratory where three of the cores wmwashed tbrough 2000 pn and 850 pm

shed mesh sieves to expose clams. The clams were removed, counted, and preserved in 70%

ahanol. Demity of clams was detennined hmthe mean number of clams found in the three

cores. The fouth core wss dnad anci ashed to daennine orgmic content according to methods

outlined in Standard Methods for the Examination of Wata and Wastewater (American Public

Health Association 1995). Homogenized subsamples were dned in preweighed evaporating

dishes, weighed and ipaited in a muffle ftniace at 550°C for one .hou. The weight of the

remaining aoh teprescated the inorganic content and the lost weight represcnted the organic

content of the sample.

At aii site where quantitative samples were taken, four envitonmental variables were measured as follows: (1) watcr temperature (OC) with an alcohol thennoman, (2) dissolved

oxygai (% don),and (3) conâuctivity (rnicmSicmens - CS) with a Comhg Checkmate

Moduiar Meter System (Corning Inc., Coming, NY, USA) and; (4) pH with a Canlab *

(Mississauga, ON, Cd)portable digital pH meta Md607.

Results

(hie hundrcd and stventy-scven si- in the Lowa Torpy River watershed plus Pass LaLe

wmexaminexi for the pnsence of hsh&ttcr rnolluscs. Eighty of the LTR sites were deemed

unsuitable due to hi@ discharge or roc@ substrates, 25 sites appeared suitable but no moiluscs

were found, and 24 sites had moiîir9cs but an extnmely low density of clams, or subsûate

character (e.g*, dense plant mots) prohiiited quantitative sarnpling. Appximately 27% of the

total numbcr of sites examincd (i.c,20 lotic sites and 28 kntic sites out of a total of 177 sites) were sampled quantitatively for clams. Estimated densities for Pisidium casertanum at these sites ranged from 105 clams mo2to 20,329 clams m-2 (Figure 4-2). nie density of P. casertanum along the LTR road was not unifonn, and six sites of high densities (>10,000 clams uC2) were obsened at 8,21,24,28,32 and 42 km spread along the laigui of the swey area (indicated by

"*" in Figure 4-2).

O 5 t O 15 20 25 10 3 5 4 O 46 50 I DIatrnca rlong towar Totpy R tvar Rord in km

Figure 4-2. Density of Pisidium casmumm along the hwer Torpy Riwr Road. "*" indiates area of high density (> 10,000 m-2).

Lotic Habitats

The mean d&ty of clams and enviromenta1 conditions measured in the twenty lotic habitats are shown in Table 4-1. In seven stnams, it was possible to mess natural upstream pools of a variety of riparian conditions in orda to assess variability in clam density within each stmm. In three of the stream, two additional pools wae found upstream, and a third was found in another stream (Table 4-2). In 64% of the cases (Le., 12 of 18 pools examined), the pools at the culverts had densities of P. cusertanum that were sixniiar to the upsûeam pools (Table 4-2).

In the two smams whcn statistically sismficmt diffmces in clam de~itywefe fond, A010 had a rather srnail cuivert pool dmsity end no populations were detected upstnam, while at 87 A022, the density was significantly higha at the culvert pool than in upstream sites. While the riparian condition classification of these latter two stnams was old clearcut, there were also two old clearcut streams with similar culvert and upstream clam dnisities.

Table 4- 1. Average clam deasity and environmental conditions (mean f SE [standard error]) in al1 categories of habitat and riparian condition in the Lows Torpy River watershed. Habitat No. Density Orgmic Temp. Dû - r Cond pH s.~w~'Lo. Type rites clrma/m2 % OC @ Loticbbih~ 20 2,947 f 536 27 I4 11.8 f 0.4 77 f 2 266 f 23 7.40 f 0.08 (poold) h 1 Unloggui 4 2,686 f 1,547 34 f 9 10 f 1 85 f 1 236 154 7.26 f0.28 Old Clarcut 10 2,749f 701 23f6 12.6f0.5 72f4 279f37 7.41k0.11

Riparian 1 5,846 30 13 80 303 7.75 Rcserve Zone Lcn*cHiiwb- - 28 5,496 f 922 25 f 3 14 f 1 62f3 222f22 6.71f0.11

Pond 1 3 [2,493f19229131f4 (14f2 I77f9. 1273f19 I7.05f0.35

Table 4-2. Culvert and upstteam dnisities of Pisidm cusertunum. "*" indicetes density is significantly diffeiat than culvert dcnsity at P < 0.05. Ri~arianCondition

nie twenty streams with populations of P. casertanun, at the culvert pools were put into

four categories accordhg to the upstream riparian oondition (Table 4-1). The Riparian Reserve

Zone had the highest mean density of clams but the sample size of one precluded meaningful

comparisons. Statistical evaluation of these data failed to find significant ciifference between

riparian condition end clam densities or environmental conditions regardless of how the groups

were compared (Table 4-3). Post-hoc testing of the 36 possible pair-Wise cornparisons failed to

find significant pair-Wise differences (P > 0.05). niese results indicate that al1 types of nparian

conditions in the LTR watershed have statisticaily similar clam densitin and envVonmentd

conditions at the culvert pools.

Table 4-3. Resuits of ANOVA of density of Pisidium casertunum at culvert pools and various combinations of upstream ripaian conditions in the Lower Torpy Riva watershed.

------r Hypothcrir Testcd Test Rciiilt Probability 1 ~=)~u-=~~~~~=~~-=~~~ipna--F(3,16)=0.482 P=0.699

Lentic Habitats

The twmty-eight laitic habitats wae categorizcd by habitat type (Table 41). The mean

clam density ranged hm2,493 clams mo2in poad Mitais to 8,506 clams m-2 in caneil habitats,

which also had the leest organic content in the seùimcnts, and the lowest conductivity and pH.

Howwcr, statisticai cvaluation of these data failed to fhd significant difference between lentic

habitat type and clam dawities or enhmental conditions (mdtivariate ANOVA: H, =

Post-hoc testhg of the 60 possible pair-mise cornparisons found no significant differences (P > 89 0.05). These resuits indicate that all lentic habitats in the LTR watershed have statistically similar clam densities and environmental conditions. This data also showed that the conditions in the four habitat types created by forest practices (water accumulations, ditches, cattails and pools) were not significantly diflmnt âom those observed in the naturailysccming pond habitats (multivariate ANOVA: H, = krndldc = bd:Wilks' Lambq6~~)=0.789, Roa's &6~0)=

0.893, P = 0.5 18).

Lotic vs. Lentic Habitats

A cornparison between the pooled data for lotic and lentic sites revealed a signifiant diffnmce between these habitat types (muhivariate ANOVA: Ho: bai, = CL(rntiC; Wilks'

Lambqspa1 = 0.472, Roa's h6*40)= 7.458, P < 0.001). Post-hoc testing found significant diffaences in: (1) density of P. cusertanum, with lotic < lentic; (2) water temperature, with lotic

< lentic; (3) dissolved oxygen, with lotic > lentic; and (4) pH, with lotic > lentic (Table 4-4).

The direction of these diffèrcnces suggcsts that movement of the water is the driving force causing the diffefence in the measurements. Higher densities of clams were fouad in lentic habitats with les water movnnat and higher water temperature, and with lower dissolved oxygen and pH values.

Table 4-4. Cmparison of lotic anâ lentic habitais (mean f SE) in the Lowa Torpy Riva Watershed and probability lcvel of diffctctlces in means. Factor Lotic Lentic Test Renilt Robrbllily (pookd ha) (irookd dm) L Density (clams m4) Organic Content (%) 27 f 4 (n = 20) 25 f 3 (n = 28) Ftlmm= 0.171 P = 0.682 Community Composition

Fifieen taxa of molluscs were found in the Torpy River watershed, comprishg eight taxa of sdsand seven taxa of clams (Table 4-5). No fnshwater mussels were found. Freshwater clams of the genus Pisidium wen the most common molluscs with five species, while the snail genus Gyruulus comprised three species, and the clam genus Micsculium two species. The mainhg five genna of snails had one taxa each. Five of the taxa collected occmed only in

Table 4-5. List of freshwater molluscs and their habitats in the Torpy River watershed.

Fieshwater MoUuscs Taxon Habitat m Subclur Prorobnachh F8- vlilvnadrt Valvata lewisi lewisi Subclus Rilmomti LYlDMtidrt Fossariu prima stream, wata accum, ditch, catîaiis Stagnicola cutascopium catascopium kake F8dy Phyddae Physella sp. lake, cattails, pool, pond Fmily Pianorbidie Gyrmlw circumtn'atirs lake Gymului dejlctus lake Gyrml~~~pimw lake, stnam, ditch, cattails, pool, pond Planorbella mbctenata lake Gllwmaw Famiiy Spherikire (dams) MwcuIium lacustre cattails, pod, pond Mwculium sema lake, cattaiis, pond Pisidium casertamm lake, ~beam,water accurrmlations, ditches, cattails, ponds, pools Pisidium compresmm lake PisUiium fmgintwrn pond Pisidium nùfium cattails, pond PLrUiium wntncomm cattails Pass Me, which, as a large lentic wata body was a diffmt type of habitat fiom the others examined in this study. While some of the remaining ten species were found in the lalce, they were also found in various habitats thtoughout the LTR watershed (Table 4-5).

in lotic habitats, in addition to P. casertanumI some collections of Fossaria parva and

Gyraulusparvus were made at both culvert and upstream pools. In the lentic habitats, ten taxa of molluscs were found of which seven taxa were found in both the natural and the created habitats.

The clam Pisidiumjemgineum was found only in one pond (natural), the ciam P. ventncosum was fond only in one cattail area (created), and the snail Fossaria parva was found only in several of the created lentic habitat types.

Discussion

At lotic sites, the cornmon mollusc Pisidium ctzsertunwn was found at similu or pater densities at created cdvert pools as compd to naturai upstream pool sites. Given this observation, it appears that in the LTR watershed, the installation of dverts for the constnrction of forest acceas roads has increased the nmber of lotic habitats for, and thus the abundance of P. casertunum.

The five categories of lentic habitats idaitifid were visually distinct, but not signifimtly différent in tams of dam dcllsity or enviromenta1 conditions. Clam density in the four types of habitats created by forest practices was smiilar to that found in the nahirally- dgponds. Given this observation, it appears that in the LTR watetsheâ, forest practices have indthe number of lentic habitats for, and thus the abundance of P. cumtunum.

There does not appear to be a measurable doumsûeam effkct on clam population density with respect to upsûcam riparian condition (Taôle 4-1) although the sample size was Iimited in some cases. It may be that the thick, herbamus riparian vegetatioa that pwsin the LTR anas continues to provide SuffiCient buffering apacity to the strrems and surroundhg mil regarâless of the extent of timber hmest. Another possible explanation is that the derisity P. cusertanum at the culvert pools is not related to the amount of sediment deposited and so this clam is may not be an effective monitor of the quantity of downstream sedimentation.

Lotic and lentic habitats differed sigeificantly in the density of P. casertanum and ig several environmental conditions, with clam density significantly higber in the higher temperature lentic habitats. EndothRmic animals, such as P. casertanum, ofien have increased metabolic rates with increased temperature. This was confimeci by Hornbach (1985) who found variability in the metabolic rates of khwater clams related to environmental factors. in specific studies of P. casertanum. Hornbach and Cox (1987) found a significant differmce in fecundity for P. casertanum in two ponds of diffaing quality. In the pond with more favourable conditions, P. casertanum hdincreascd reproductive output and young bm early in the season wae able to reprcxiuce during the same season. Fecundity was lower in the les favourable conditions. in the present snuly, it is possible that the LTR lentic habitats wmmore favourable for pwthand reproduction than the lotic oms. Habitais with higher temperature regime would mult in an inaeased metabolic rate of clams, and consequently, an inincrrased reproductive

output. Thus, the significantly highcr clam density obsdin the lentic habitats may be , associatecl with the sipifiamtly higùa temperature mdthm.

Al1 of the fifian species of fkhwatcf moiiusc found in the Torpy River watershed are cornmon in Canada (Clarke 1981), although Mt~sculiurn secwis, PPidium milium and P. ventncomm had not bem ncotded pmiously hmnorthem BC. The lotic sites in the LTR watershed hosted three species of molîuscs that wnc fond in both the nahnal and culvert pools.

The lentic sites hosteû 10 @es of molluscs. Of the three lentic molluscs appearing to be distriiuted différently betwecn created and natural habitats, P. ventricosurn was fomd only in one crcated cattaü habitat and P. fenugîneum was found only in one natural pond. Results obtained throughout northern BC (Chapter 2) indicated that P. ventn'comm may be able to tolaate conditions of lower conductivity and pH than am P. femginetcm and so can occupy some habitats unavailable to P. femrgineum. However, in the LTR watmhed, P. vennicosum was collected at conditions within the range of those recorded for P. femcgineum thughout northem BC so the diffèrent distributions motbe explained by the current information.

Fossaria purvu was found in lentic habitats only at crmted sites. Its absence hmthe nahual ponds may be a collection artifact as very few specimens of this spacies wae collected in the

LTR watershed, and it was collected at natural lotic pools. in gend, however, the divetsity of fieshwater snails and clams in the LTR watershed was similar in both naniral and mted habitats. Thus, this study found no change in the diversity of fieshwater molluscs as a result of forest pctices but did find apparent inmeases in abundance.

Unfortunately, there is no way to detefaune that arnount of molluscan habitat that was impmed or lost due to forest praaices in the LTR watershed. It is clear howevcr, that landscape alteraiions asdated with forest pradices CM pmvide habitat for certain Wwater molluscs.

In this study, creatd culvert pools and lnitic habitats were found to provide suitable habitats for the Wwaîer clam Pisidium casertanuni and other localiy occuning freshwata molluscs. In the case of culvert pools, these habitats may support pater clam densities than can nanaal upstream pools. This impact of fomt practices is likely to be cunfined to those orgmisns with habitat requÛemeats tht inc1udt standing watn and the accmulation of scdiments. Additional research is warranted and should be diracd towarâs particular taxa and bctionai groups. CHAPTER 5 - INTEGRATION AND CONCLUSIONS

A goal of the largescale spatial study in northern BC was to record hhwater rnollusc biodiversity. As time was limited, site selection was skmed towards large, vegetated, lentic water bodies which contain a greater diversity of molluscs than do lotic or smaller lentic sites

(Lassen 1975). Conversely, in the small-scale spatial study in the Lower Torpy River (LTR) watershed, al1 aquatic habitats adjacent to the access road were assessexi for mollux: pnsence.

The rdtsof these different site selection criteria are apparent hmhistograms of the number of species per site with lentic and lotic sites distinguished (Figure 5-1). For example, in

Figure 5-la, the large-scale sndy, four species were collected at nine sites, four of these were

lotic sites and the nmaining five were lentic whereas in Figure 5-1 b, the small-sale study, four

species wae collecteci at only two sites, both of which were lentic. Of the 112 large-scale

ecological sites (Torpy River ana records N 11 10 and N 11 1 1 removed hmoriginal 114 sites) plotted in Figure 5-1 a, only 12% were Iotic sites. This is in contrast .to the 98 smd-sde LTR

sites (177 sites minus 80 hi@ dischqdgravel substrate ctteks plus Pass Lake as per Chapta 4)

plotted in Figure 5-lb where 52% wmlotic sites. The lotic sites in the large-scale study were

oftm slow moving areas of large rivas, which yielded up to 12 species of molluscs (Lee and

Ackerman 1999a), whaeas in the smdl-scaie study, the smaü tribu- aream yielded a

maximum of thce specics of molluscs (Chapta 4). Figure Ela also shows site selection bias

towards potcntial high àiversity molluscan habitats in that only 5.3% (6 of 112 sites) of the sites

selead in the largc-scaie study did not contain mo~luscs.Convasely, Figure E1 b shows that in

the small-scale stuày, 25.3% (25 of 99 sites) of the did not contain moliuscs Furtha, in the

large-gale ondy, 12.5% of the sites had one or two species, whereas in the smali-de stuây,

63.3% of the sites had one or two species. Thus, both the type and the size of sites examined

wzre factors in the fkshwata moilusc diversity found. ! ILentic sites : O Lotic sites

O No. d spseir

Figure 5-1. (a) Number of species per site et ecological sites in northern British Columbia (large destudy) with pcrcentage of sites pa species nmbaand number of laitic and iotic sites per species number. (b) Numk of @es per site in the Luwer Torpy River watdtdand Pass Lake (d-SC&study)with Oefcentage of sites per species amber and number of lentic and lotic sites per species number. in the large-scale study, the mean number of species per site (excluding bbû"sites, n =

106) was 7.3 with 56% of the sites below, and 44% of the sites above the mean resulthg in a relatively normal distribution. In the small-sale study, the mean numba of species per site

(excluding 'Y)" sites, n = 73) was 1.7 with 38% of the sites below, and 62% above the mean so that the distribution is skewed to the low end of the scale of the nwnber of species.

If site selection in the small-scale LTR study had been based on the same criteria as it was in the large-sale northern study, it is likely that only Pass Lake and one of the natural ponds would have been examined. This would have resulted in nhe species mllected hmPass Lake and perhaps 6 species collected hma pond for an average of 7.5 species per site. 'Ihis is vay close to the average nmbaof species per site for the entire northem study (7.3). Eleven taxa of molluscs wouid have been recordai hmthe LTR watershed (nine species from Pass Lake and two additional species hma pond), whaeas the intensive study yielded 15 species in total. Of the remeining four species, thne wat oollcctd in neaiby sites (on a large de)aud so theh patterns of dise'butions in northem BC wae would not have been significantly affected by the absence of th& records in the LTR area Howcver, the one rrmainiag species, Fossda pm, has only beai mrded in nortbem BC hmthe LTR watershed. The intcnsity of this small- scaie study added information not obtaind by larger de, less intense site selection. As discusseû in Chapter 3, more intensive searches (i.e., longer search timts) can result in the collection of -ter numbers of Spccics. More intnw sampling in northem BC may discover additional @es.

The dtsof the large ad d-scale stuâies are examples of how scale determines study design and thus affects the outcomc Accordhg to Levin (1992), scaliag issues affect al1 ecologicai investigations and the problan of nlating phenornena aimss scaies is the central probiem in bioiogy and in d of science. In this sndy, this probiem is exempiified by the diffaait site seltction aiteria rsquind when the scales were of différent magnitudes. The

97 creation of additional suitable habitats for local Wwater moHluscs found in the mdl-scale study cannot be extrapolated to the patterns of distribution found for rnolluscs in the large-scale study. nius, the integration of the results of these two studies is problematic.

However, the combination of these large and small-sale studies pmvides important information for the maintenance of biodivasity and for the conservation of the freshwata molluscs of northern BC. Mollusc community composition changes that may result hmhabitat change could be tracked hmthe distributions~of rnolluscs recorded herein. The water conditions thtit appear to affect the distribution of the molluscs could be used for restoration of habitats and to predict potaitial impacts of perturbation. The ubiquitous freshwater clam

Pisidhm cusertantm rnay provide a useful measwe to assess the quality of certain types of

aquatic habitats created by landscape alteration. This study advances our hiowledge of the diversity, distribution and ecology of the kshwater molluscs of northern BC and provides a basis for the protection of these integrai units of inland quatic ecosystems. Aldridge, D.W. 1983. Physiological ecology of freshwater pmsobranchs. Pages 329 - 357 in The Mollusca. Volume 6: Ecology. W.D.Russell-Hunter (ed). Academic Press, London. American Public Health Association. 1995. Standard Methodr for the Examination of Water and Wmtauater. 19'b Edition. Washington, DC. Baker, F.C. 1911. Lymnaeo of North America. The Chicago Acaderny of Sciences. Special Publication No. 3, p i-xvi + 1-539,58 pls. Berg, K. and K.W. Ockelmann. 1959. The respiration of freshwater snails. llre Journul of Ekperimental Biology 36: 690 - 708. Bogan, A.E. 1998. Freshw8ter molluscan conservation in North Ametica: problems and practices. Journal of Conchology Special Publication No. 2: 223 - 230. Booth, J.W. and G.B.J. hissart. 1998. An investigation of interspaator variability in band searching for terrestrial macromolluscs. Abstracts of the World Congress of Mulacology. Bieler, R. and P.M. Mikkelsen (eds). Field Museum of Natural History, Chicago, IL, USA. Boss, K.J. 1978. On the evolution of gastropods in ancient lakes. Pages 385 - 428 in: hlmonates Volume 2A: Systematics, Ewlution and Ecology. V. Fretta and J. Peake, (eds). Academic Press, London. Box, LM. and J. Mossa. 1999. Sediment, land use, and neshwata mussels: prospects and problcms Jwrnal of the North Amm*canBenthological Society 18(1): 99 - 117. Boycott, A.E. 1936. The habitats of hh-water molluscs in Britain. Joumul of Animal Ecology 5: Il6 - 186. British Columbia Minisûy of Fores&. 1995b. Forest Cova Map Series: 1:20000 scale. inventory Branch, Ministry of Forests, Victoria, BC, Canada British Columbia Ministry of Forests. 1995a Forest Practices Code of Bntish Columbia. Forest Rwd Enginehng Guidebook BC Ministry of Forcsts, Victoria, BC, Canada British Columbia MUUstry of Forcsts. 1998. Forest Practices 'Code of British Columbia Opemtiona~Planning Rqu1ation.s; Part 8: Riparian Ma~gementAreos. BC Wstry of Fora&, Victoria, BC, Canada Brown, KM 1991. Mollusa: Gastmpoda Pages 285 - 314 in: Ecology and CIussijication of North American Freshwatler Iirwrlebrates. Thop, J. H. & A.P. Covich (eds). Academic Press. Brown, KM.,LE. Aiexanda and J.H.Thorp. 1998. Ilifferences in the edogy and distniution of lotic pulmonate and prosohch gastropods. Amencan Malacologicl Bulletin 14(2): 91 - 101. Bmwnlee, ML, B.G. Shephd and DR Bustard. 1988. Some @ects of forest hurvesting on water plity in the Slim Creek watershed in the centml interwr of British Columbia. CdanTechnical Report of Fisher= and Aquatic Sciences 16 13. 41 pp. Bryce, O. W. Jr. 1 970. Rediscovery of the limpet, Acroloxus coloradensis (Basommatophora: Aaoloxidae), in Colorado. Nuutillus 83(3): 105 - 108. Burch, J B. 197%. Freshwater Sphaeriucean Clams (lk6ollusca: Pelecypoda) of North America. Malacological Publication, Hmburg, MI. Bufch, J.B . 197%. Freshwtatet Unio~ceanClams (Mollusco: Pelecypoda) of North America. Malacologicai Publications, Hambwg, MI. Burch, J.B. 1989. North Americun Freshwater Snails. Malacological Publication, Hambwg, MI. Burky, A.J. 1983. Physiological Ecology of Freshwater Bivalves. Pages 281 - 327 in: The Mollurcp, Volume 6: Ecology. W.D.Russell-Hunter, (ed). Academic Press. Cannings, R. and S. Cannings. 1996. British Colunbia: a Natuml History. Greystone Books, Vancouver, BC, Canada. Carlson, J.Y., C.W. Andrus and H.A. Froehiich. 1990. Woody debris, channel features, and macroinvertebrates of stnsms with logged and undisnirbed riparian timber in northeastern kgon, USA. Canadian Joumuil of Fisheries udAquutic Sciences 47: 1 1 O3 - 1 1 1 1. Clarke, A.H. 1970. On Acroloms coloraden& (Hende~on)(Gastropoâa, Basommatophora) in eastern Caapda Natio~fMweum of Natural Sciences, Publications in hIogy, No. 2 National Museums of Canada. 13 pp. Clarke, AH. 1972. Field notes. Available hmthe Canaâian Museum of Nature, P.O. Box 3443, Sb. D, Ottawa, Ontario, Canada KlP 6P4. 36 pp. Clarke, A.H. 1973a Field notes. Available âom the Canadian Museum of Nature, P.O. Box 3443, Shi. D, Onawa, Ontario, Canada KlP 6P4. 28 pp. Clarke, A.H. 1973b. The Freshwater MoUuscs of the Canadian Interior Basin. Malacologia 12 (1- 2): 1 - 509. Clarke, A.H. 1979a Gastropods as indicaiors of trophic lake stages. Nuutillus 94(4): 138 - 142. Cl*, A.H. 1979b. Sphaeriiâac as indicators of trophic lake stages. Nuutilus 94(4): 178 - 184. Clarke, A.H. 198 1. The Fmhwuter Miwa ufCa&. National Museum of Naturai Sciences, Ottawa, CaMda. Cornmittee on the Status of Endangd Wildlife in Canada 1998. Canadian Species at Risk. Canndian Wiidlife Service, Envin,nmmt Caasda, Ottawa, ON, Canada 19 pp. Cod, K. and B. Ciemmt. 1996. Rclationship bnweai fnshwater gastropods and plant

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I wish to thanlt the members of the Physicd Ecology Laboratory at the University of

Northem British Columbia for th& assistance with these projects. Particular thanks is due to

Leanne Wilson for her assistance in the field. Thanks is also due to Dr. J. B. Burch for his pemiission to use many of the figues presented in Appendix 1.

Work at the Canadian Museum of Nature was undertaken with the assistance of Dr. Jean-

Marc Gagnon, Chief Manager, uivertebrate Collections and Dr. Andn Martel, Research

Scientist. Wonnation hm the Royal British Columbia Museum was obtained hm Kelly

Sendall, hvertebrate Collections Manager.

Mapping of collections sites was with the instruction and assistance of the Geographic

Infomiatiün Technical staff, Charlaie Vantyghcm and Kara Woodcock, at the Conservation Data

Centre, a unit of the Resowce and Inventory Branch of the Ministry of Environment in Victoria,

BC.

The cornmittee overseeing this project was compriscd of my supervisor, Dr. Josef Daniel

Ackaman, as well as h.Max Blouw, Dr. Ellai Petticrew and Dr. Roger Wheate acting as members, and Dr. Andre Martel as the ExtdRcviewcr. Many thenlcP go to them for theh support of this work, and to Dr. Ackerman for his thorough rrviews of the Qaffs of this thesis.

Funhg for this study was pvided by fiinding hm a Forest Rcnewal BC gcant, the British

Columbia Consemation Data Centre, the Committee on the Status of Endmgered Wildlife in

Cauada, and the National Science and Engineering R*~atrhCoud to Dr. J.D. Ackerman. Table A-1. Site number, collection date, site description, NAD83 UTM coordinates and environmental variables for locations of tieshwater mollusc collection sites in northem British Columbia.

Table A-2. Systemstic listing of the fkshwater mollusc taxa of northern British Columbia including figure numk of distribution rnap in Appendix 1, maximum sheU sue (hmClarke 1981), and occumnces out of 176 sites. Unammon species were found at SI0 sites, cormaon species were found at 11 to 50 sites, and very common spies were found at >M sites.

Taxa summariefliguns Al - A-63. Distriiution maps, location information, and environmental variables (where measured) and discussion of fïndings for the 63 taxa of freshwata molluscs identified hmnorthexn British Columbia, Classification and nomenclature are as listcd by Turgeon et al. (1998). The length of the sale bars in the illustrations of the molluscs is 1 mm.

Figure A-64 - Ecological sites where molluscs wne not collected. Figure A-65 - The ecoprovinces of northern British Columbia

Table A-1 (cont.). Site number, collection date, site description, NAD83 UTM coordinates and environmental variables for locations of freshwater mollusc collection sites in northern British Columbia. Legmd: ZN = NAD83 UTM zone number, EAST = NAD83 UTM easting coordinate, NORTH = NAD 83 UTM Northing coordinate, TEMP = water temperature in "C, DO = dissolved oxygm, COND = conductivity in microSiemens, caU = caîcium concentration in mgn as derïved fiom Rodhe (1949).

'L~CATION ZN EAST NORTH TEMP culvoslod strsam tlowing uadcr Hwy 97 S of Ft Nelson 10 516933 6476264 18.5 Andy Bailey Istc, Ardy Bailey Rec. Arca 1 0 Perkcr kPW of Ft Nelson 111 swamp about 148 km up road to Hclmut 1(1 pond about 132.8 km up rioad to Helmut 1O woody swamp with beaver lodge abut 1 19.4 km up road to Hctmut 10 ewatfl~/pondon botb eibof d about 103.4 km up mad to Helmut 10 canai1 arca about 87.8 km up rPad to Hclmut 1O N1040 ,199708 13 swarnp on both ai& of road abut 68.1 la-up d to Hclmut 1O NI041 1W70813 swampaboul47.5luauproadtoHehut 1O 3 swampabout 28.8 lanuproad toHclmut 1 O 4 Beevct Pond Rcc, Site, about 10 km N on Fort Liard Hwy 1O 14 Summit Lakenirc,Smm Mt. hv.Part<, at campground [same site as MN 10 131 1O 4 lakc just W of Summit Lake, Stone Mounlaùi Provincial Park 1O 4 swamp/bcaverpond at Toaâ River 1O S Muncho Lalrc, Muncbo LaJm PmMncial Par& 10 5 lekc 10.4 km NW of bridge ovcr Smith Rvr. betwacn Hwy 97 and Liard Rvr. 9 5 small pond 2.3 lan NW of bridge over Smith Rvr on opposik si& to Liard Rvr 9 6 srnall pond on si& of Hwy 97 past Firesiôc 9 6 awamp/pod on si& of Hwy 97 1 1 km pas1 (NW of) site N 1050 9 6 lakt on N si& of Hwy 97 (no namc in BC gazctttcr) 9 lake 13.6 km NE of Hyland River (in Yukon) 9 Wyc 1,in Watson 1(comm.), Yukon 9 Sccond Wyc Lake, in Watson Lake (corn.), Yukon 9 High bnGc,juat into BC hmYukon on Hwy 37 9 Connier Creek, 5 km S of Hi~hiakc 9 Blue ïake, on W si& of Hwy 37 9 Blue i,on E si& of Hwy 37 9 Twenty-tight Mile Creek 9 swamp on E si& Hwy 37 S of Balriag Powder Ck, just N of Bcaver Dam Ck 9 Boya rnko, Boya hkc ProMncial Park 9 Good Hope Lake 9 Table A-1 (cont.). Site number, mllection date, site description, NAD83 UTM coordinates and environmental variables for locations of fieshwater mollusc collection sites in northem British Columbia. Legend: ZN = NAD83 UTM zone number, EAST = NAD83 UTM easting coordinate, NORTH = NAD 83 UTM Northing coordinate, TEMP = water temperature in Y, DO = dissolved oxygen, COND = ductivity in microSiemens, ~a*= calcium concentration in mgll as derived from Rodhe (1949).

-19970823 Lake KaihIya, in Smitheirr 9615074 6076443 21.1 91 116.5 16.0 6.90 19970824 Round Lakesltc,SE of Srnitbers 9 633278, 6059269 17.4 91 275.0 39.7 8-73 19970824 Buiiûey River, af E si& of Houston 9 6532211 6031120 16.3 55 211.0 30.1 6.40 19970824 Fulton River, ncar Toplcy Wingat Fuiion River Salmon Projcct (live) 9 6812841 6077748 17.9 71 86.7 11.6 7.25

Table A-l (wnt.). Site number, collection date, site description, NAD83 UTM coordinates and environmental variables for locations of freshwater mollusc collection sites in northem British Columbia. Legend: ZN = NAD83 UTM zone number, EAST = NAD83 UTM easting coordinate, NORTH = NAD 83 UTM Northing ooordinate, TEMP = water temperature in OC, DO = dissolved oxygen, COND = conductivity in microSimens, ~a*= calcium concentration in mgll as derivcd hmRodhe (1949).

Table A-2. Systematic listing of the fieshwater mollusc taxa of northern British Columbia including figure numba of distribution msp in Appeadix 1, maximum shell size (hm Clarke 198 l), and occurrences out of 176 sites. Uncornmon species were found at 110 sites, common species were found at Il to 50 sites, and very common species were found at >50 sites. 1 Cliss Gistropodi 1 Figure 1 Shen She (mu)1 Occurrence 1 , Subclus Rorobruchia , FamUy Vdvatidae

, Valvata lewisi lewisi A- 1 5 mm wide 42 - cornmon Valvata sincera sincera A-2 7 mm wide 40 - comrnon Valvata sp. A-3 da da

, Family Acroloxidae Acroloxus cdorodensis A-4 4.6 mm long 7 - uncornmon

------, Fossaria galbana A-5 1 1 mm hi& 4 - uncornmon Fossaria modicella A-6 9.5 mm hi& 9 - uncornmon Fossaria pana A-7 8 mm hi& 1 - uncommon Lyninaea athzaensis A-8 42 mm hi& 5 - uncornmon

, Lymnaea stagnalb oppressa A-9 56 mm hi@ 33 - cornmon Lymnaea sp. A-10 da nia Stagnicola arctica A-1 1 22 mm hi& 26 - cornmon Stagnicola caperata A-12 16 mm hi& , 4 - uncornmon 1 Stagnicola catascopium cataiscopium 1 A-13 [ 33 mm hi& 1 7 - uncornmon 1 Stagnicola el& A-14 . 32 mm hi& 62 - very cummon Stagnicofo sp. - juveniles A45

Physella ld A-20 26 mm hi& . 2 -uncornmon Physe I la propinqua A-2 1 19 mm high 2 - uncornmon Physella virgtnaz A-22 17mmhigh 1-unconmion Physella rghti A-23 9.1 mm high 1 - uncommon Family PhobMI, Gmlwcirculllstrrutus A-24 5 mm wide 70 - very common Gymuluï crista A-25 3 mm wide 4 - uncornmon G'Iw ddectus A-26 8 mm wide 33 - common

, Gyraulwpurvt~p A-27 5 mm wide 28 - cornmon

Gy~atrlwvmicvlaris A-28 . 7mmwide 10-uncammon i Menetus owcularis I A-29 i 8 mm wide I 10 - uncornmon I Table A-2 (cont.). Systematic listing of the fkshwater mollusc taxa of northem British Columbia including figue number of distribution map in Appendix 1, maximum sheil size (hmClarke 198 l), and number of occmeaces at the 176 sites. Uncornmon species wne found at 510 sites, cornmon species wae found at 11 - 50 sites, and very cornmon species were fond at >50 sites. F8dy Plrnorbidre (cont.) Figure SheU She [mu) Occiunnct Planorbula anniaera A-3 1 8 mm wide 2 - uncornmon . -.. Planorbula campestris A-32 12mmwide 5-uncommon Helisoma ancevs ancms A-33 20 mm wide 9 - unconmon ------. . - .. -- -. - -. - . . -. - .- Helûma sp. A-34 da da Planorbella binneyi A-3 5 32 mm wide 3 - uncomaion Planorbella subcrenata A-36 32 mm wide 59 - very coma Family Ancylidr

FemSsia fiagilis A-37 5.5 mm long 1 - uncornmon I Ferrissia parallelus A-3 8 7.6 mm long 3 1 - cornmon Femisia sp. A-39 da 1 - uncornmon

, Clms BiviMi Famil37 Mirguitiftridc Mogaritifera/acata A4 125 mm long 8 - uncornmon FImily Unionidre Anodonta kennerlyi A41 120 mm long 22 - cornmon Fimlly Sphmiidie 1 Spihuerinun nitidum 6 mm long 1 18 -conunon

Sphamenumsimile A4 25 mm Sphaerium striatintlm A45 14 mm Mt~~mliumlacustre A4 14 mm Musculium securis A47 6nun Mwculium trunmemm A48 15 mm Pisidium casertamm A49 5 mm Pisidium comvressum A40 5.5 mm

Pisidium f0lla.x 1 A-52 1 3.5- Pisidium fenupineum 1 A43 1 3 mm

Plririum insigne 1 A-55 1 Zmmlon~l l-mcommon 1 Pisidium liI&eborgi A-56 4 mm long 15 - cammon Pisidium milium A957 3 mm long 20 - common Pisidium nitirhrm A48 3mmlong 13-common Pisidium punctutum A49 1.7 mm long 1 - unoommon

Pisidium mtundatum Ad0 3.3 m long 1 - uncornmon - Pisidium vmf'rtble 1 Ab1 5 mm long 48 - common Pisidium venîràcosum 1 A62 1 3 mm long 1 25 - cornmon 1 Pisidum sp. I I da I 1 -uncornmon Valvata lmisi lewisi* Curriei, 1868 Fringed Valvata

DRAINAGE/WATERSBED PACIFK; Fraser: Frrxr (2),kchalro (7)3twt (3); Nasi: Meziadin (1); Skm:Babinc (1). Buikiey (2) Stikint: Stikine (4) ARCTIC: Lm:Dcasc(5)Jt Nelsoa(6),Liard(3), Td(1) Ptrct: KisLntinaw (l),Pcace (S),Piot (1) ECOPROVINCE/ECOREGION hdPI.ias: Central Albcrra Uplands (1)Qeacc River Basin (1 ),South Alberta Uplandp (2) Cenîd Interfor: Fraser Pbttnu (6) .. - .. -- - - - . - - Coast & Moan~Nass Basin (1) Figure A4 - Collection sites for Valvata lewisi lewisi. Northem BadMoantiinr: Norihern Canadian Rocky Mountaias (i), Liard min (S), BIûGEûCLlnUTIC ZûNE Boreal Mountains and Ptniraiin (6) Botcal White and Black Sprucc (23) SubBûrtd interion (lO),Central EngeImaim Spruce - Subdpinc Fi (1) Fraser Basin Interior Cc& -Hemlock (2) Craidian Roclçy Mounteins(S),Sloana Mts, (1) Sub-Bad Spnicc (16) TdpWu: Hay River Lowîaruî (4), Nonbmi -UPI~ (2)

Dissolved 02(% Saturation) 32 69.18 3.36 15.00 99.00 Conductivity (psienmu) 32, 252.48 27.40 73.60 735.00 Calcium hWlitrc) 32 36.3 1 4.09 9.64 108.25

Revio~alyneorded &tribation hi northern BC: Thmughout aorthan BC (ClarLe 198 1). Dkusriopi: Vahatu lewisi leiwas a common mo11usc in ILOrfhem BC king fmd at 42 of 176 sites. It was foumi in bth th PPcinc and Arctic drainages ad in aU of the ccoprovinces within the stuây ana. The four BGC rows in which it wu found have man average tempaatims of -3.0 to 8.X with up to 7

mm. Teraperatrw: Fiw2-9a shows that Y. 1-i lewisi was found at temperatures >2S°C suggesting temperature may not be a limiting factor in the distribution of this species in northern BC.

Dissolvcd ûxypetl: Figure 2-9b shows that K lewisi 1-i was found in habitats of relatively low dissolved oxygen (215% saturation). While prosobrancbs are generally described as less hypoxia tolaaot than puhonates (Boycott 1936), this may not be the case for Y. l&i l&i and it may be oxygen- independent. Thus, the dissalved oxygen saturation of a habitat may not be a limiting factor in the distribution of this spccies in notthem BC.

Conductivitv and Calcium Concentration: Figure 2-9c shows that Y. l&i l&i was found at a minimum calcium concentration of 9.6 mga. Givm the relatively large sample size for this species (n=32), this may indicate that thae is a minimum calcium concentration requind by this species in orda to occupy a habitat. The conductivity/calcium concentration of a habitat may be a limiting factor in the distribution of this species in northern BC. paI; The mean pH for Y. lewisi l&i is significantiy lowa htfor Y. sincera sincem (Table 2-7). Fip2-9d shows that whüe both Vilwuta taxa species display nlativcly wide ranges of tola~aceto pH, Y. l&i louici was fouad at sites whae the pH was lowa than the minimum mdfor Y. sincero sincem. It appean tbiu Y. lewisi lowisi may k ôetta able to tolerate low pH levels than can Y. sincera sincera and this miy ailow Y. lewisi lewiri to ocnipy a wider mge of habitats in wrthan BC chan can Y. sincem sinceru.

Three families wac kluded in the Canonid CORCS~O~~CIK:~Aaaiysis (CCA) dysis thst includcs the Vubu& spccics (Omup 1; Fi- 2-15). The muits of this CCA are that the specics arc responding significamly to the environmental variables @ = 0.040) with 13.2% of the species piesaice accounted for). The plot shows Y. l&i lewisi to comspond to lowa than average temperature and dissolved oxygcn, neitha of wbich appesnd to k particuîarly important in its ccology as cxtrapolated hmthe range plots.

Clarke (1981) records Y. l&i lMias occwîng thmughout norihem BC, which coonas with the findings of this study. lhis widespd distri'buton gives no indication tbst any burias to its diJpersll wac encouutacd.

Accordhg to Clarke (1981), Y. lewisi lauisi occw principaîiy in lakes, ohat considerable dcpth, and dyon mud cimong submersed quatic vegctation, and it is also occssionally foimd in slow- moving rivers d in mu- pools. ClaiLc (1979s) lists Y. lewki l&i as cm iiadicator species of oligotropbic lakts but Clarke (1973b) states that it also occun in dwaür bodies in the northan part of its range. In this study, K lewisi Iewiri was foMd in lakcs anâ in slow moving rivers and crccks but it was also fouiin small wata bodies thugbut the nudy area. As this species is hwnin the northan United States hmNew York West to Minnesota (Busch 1989) and tbughout BC into the Yukon (Clarke 198 1), findings of the cumnt study would be consistent with Clarke's (1973b) statement of this taxa king found in smaller water bodies in the norihan part of its range. It may also be that in the nonhan part of its range, it is no longer so indicative of oiigotmphy as, in this study, it was often collecteci fbm small, thicûiy vegetated ponds.

*Note: This species is refmed to as ViaEvuta sincera sincera by Clarke (1973b, 1979a, 1981) but more ment authorities use Y. lewisi l&i (Burch 1989). The distinctive shell sculphullig of raiseci coiiabral striae is reflected in its common name, the fiinged valvata (Turgeon et al. 1998). Fuaily VdvUi&c VaIvoul sincm sincem Valvata sincera sincera* Say, 1824 Mossy Valvata

DRAINAGEAVATERSHED PACIFIC: Fnser: Fm(l), Ndub(IO), Stuart (3); Nam Nass (1); Skeem: Bulldey (2), Skecna (2); Stikint: Stilrine (2); Yukon: Atlin (1) ARCTIC: Li~d:Dew (@,Liard (5); Pace: Ptact (7) ECOPROVINCE/ECOREGION hm1 hina: Peace River Basin (l),Southern Alberta UpW(1) centrd Inttxio~Fraser Pheau (8) Cd& Mb.: Nass Ranges (l),Nass Basin (2) Northtrn Bord Moantrina: Banal Figure A-2 - Collection sita for Vulvata simera sincera. Moimtains and Piatcaus (7),Lhd Basin (7) BIOCEOCLIMATIC (BGC)UlNE Sub-Botd Interior: Omineca Mountains (1), Boreal White & Black Spruce (15) Frsscr Basin (12) Intcrior Ce&-Hdock (3) SpnicoWiiiiow-Birch (1) sub-Bord spnre (2 1) Enviropmcntrl Information:

Tempera~ure(OC) 29,. 18.89 0.77 8.70 26.50 Dissolvd Q (Oh Saturation) 29 71.10 4.0 1 8.00 98 .00 Conductivity (psianas) 29 237.08 36.70, 94-60 1 199.00 Calcium (mgllitre) 29 34.0 1 5.47 12.77 177.44 pH 29 7.77 0.12 6.50- 8.90- Previousiy recordecl distribuan in aorthern BC: Ciarke (198 1) does not inclde BC within the range of this mes, but Clarke (1973b) nporis a coiluxion fiom Dee~Lake, BC. Discussion: Valvata sincera sincem was a connnon mollusc in northcm BC king found at 40 of 176 sites. It was foimd in both the Pacinc ad Arctic drainages and was absent only hm th Taiga Plains ecoprovinct. The four BûCs in which this spccies was found have man average tmpatum ranging hm-2.9 to 8.X with up to 7 months klow VC and up to 5 months above 1o.C and Mth muai pncipitation ranging hm330 to 1200 mm.

The range and the means of the environmental variables for Y. sincera sincem arc shown in Figure 2-9. Temanatun: Figure 2-9a shows that Y. sincem sinceru was found at temperatures >2S°C suggcsting temperature may not be a limiting factor in the distribution of this species in northern BC

Dissolved OXY~Figure 2-9b shows that Y. sincera sincera was found in habitats of relatively low clissolved oxygen saturation (28%). While prosobrsnchs are generally described as less hypoxia tolaant than pulmonates (Boycott 1936), this rnay not be the case for Y. sincem sincera and it rnay be oxygen- independent. Thus, the dissolved oxygen saturation of a habitat may not be a limiting factor in the distribution of this specia in northem BC.

Coamiçtivitv and Calcium Concentration: Figure 20% shows that Y. sincera sincera was fond at a rninimum calcium concentration of 11.3 m@. Given the relatively large -le SU+for thW mies (n = 29), this may indiate the minimum calcium concentration rrguged by this species in orda to occupy a habitat. The conductivity/calcium concentration of a habitat may be a limiting factor in the distribution of this species in northan BC. etI; The mean pH for Y. sincera sincera is signifi~amlyhighcr that for K lewioi lewisi (Table 2-7). Figure 2-9d shows that while both Valwata îaxa display relatively wide ranges of tolaaace to pH, Y. lewisi lnviri was foMd ai sites whac the pH wu lowa than the minimum measund for Y. sincera sincem. It appearJ tbat Y. sincem sinceru may k less able to tolcrate low pH levels thaa Y. lewbi lewhi, adthat this may restrict the numbcr of habitats available to this taxa in northern BC as compeû to those avaiiable to V. lewisi lewisi.

Tbne families wen inchded in the Canonid Conespondaice Analysis (CCA) dysis tbat includes the Vahata spccics (Group 1; Fi- 2-15). The dtsof this CCA are tbat the spacies are rrspondiig si@fidy to the cnvito- dbles@ = 0.040) with 13.2% of th species presmce ' accounted for. Th plot shows Y. sinaor0 sinceru to correspond to hi- than avaage pH. Figure 2-9d and thc rcsuits of the sigdicance tcsting ch indiate that pH may be an important ecological factor for this taxa in northan BC.

Vaivrrta simeru sincera hs not kai pmiously tccorded in BC ad was previowly known in Canada only hmeast of the Rocky MoinitUiis (Clarke 1981). Weit was foui east of the RocLy Mounîains in this shdy, near Fort St. John, it wumost commonly found in the west of the sady area. Y. sincem sincem was net edltcted hmthe northeast of the ntudy area but is recordai as occ-g in norîhcm Albuta and the Northwest Tenitories (Cm1981) so it is qected that this ana is witbin its range. This wiwidespnsd distri'bution gives no indidon that any barrias to its disperd wae encountercd According to Ciarkc (1981), Y. sincm sincera is principally an arctic and sub.rrctc spccies, hosrmer, &nçh (1989) repufis Y. sincem âom as far sou& as Indiana, and Wu (1989) reports V. sincera hmColorado sa the distnbution of this species is not as Iimited to northern climes as believed by Clarke.

Clarke (1981) states that Y. sincera sincem occm in lakes, poads, slow-mohg rivers and stttams, and in m&g pools. This concuis with the types of habitats in which V. sincera sincera was found during this study.

*Note: This species is refdto as Volvata sincem helicoideu by Clarke (1973b. 198 1) but more mat authorities use V. sincera sincera (Burch 1989) or K sincera (Wu, 1989). SITES (6): CN~003,CN1008,CNI009,CNl012,CN1017,CN1018 DRAINACWWATERSHED FACIFICEFraser: Nechako (2) SCTIC; Liard: Kechüta (2); Pcra: Finîay (l), Peace (1) ECOPROVINCEIECOREGION Ceatrrl Intedot: Fraser Piateau (1) NortEicm Bord Mountrlar: Boteal MountaiPY aad Pheaus (3) Suh-Bord Interior: Fnrser Basin (2) BIOGEOCLIMATIC (BGC) UlNE Bord White and Black Spwc (1) Spru~t- WUOW- BUch (2) Sub-Borcal Spnice (3)

Figure A-3 - Coiledion sites for Vdvatu sp. Discasdon:

Thae unidentifid specirmu wcre aU odlected by Clarke anci assistants duruig the 1972 and 1973 surveys and are includeà hm to give a amplete record of khwater mollusc collections hm mnhm BC. Al1 the sites for these unidentifiai specimens are within the hown rm$e of both of the two Valvor~taxa tccogoized hmnorthern BC and wae fouid in the same drainam, CCOSdCfions and biopclimitic zones. Thus, no iofmmtion as to what taxon any of these coiicctiolls may k is @cd hmcomparisons to the distri'bution mips the two identifieci taxa. Site CN1012 is the saw site as NI003 whm Valvuta simera sinceru was coliected and site CN1018 is the same oitc as NI 103 whae Y. ldi lewisi was coUcctcd. Howewr, this ammt be uJed to imply thst btthe cumpt collection^ my k the same taxa M Wric collections as both taxa of Vilvata wat oflm collectai hmthe same sites dhg this study. Acroloxus coloradensis (Eenderson, 1930) Rocky Mountain capshell

sms(7): - NL002, NlW,N1005, N1097, N1098, N1100, Nt lOf/CNlOl5 DRGINACWWATERSHED PACIFIC: Flucr: Fnser (1). Nechako (2); Skeenr: Babinc ( l), BuWcy (1) ARCTIC: Ptace: Ptacc (2) ECOPROVINCE/ECOREGION Centrd Interior: Fraser Plateau (2) SubBorcrl Interior: Fraser Basin (5) BIOGEOCLIMATIC (BGC)ZONE Sub-Boreal Spruce (7)

Figun A4- Coliection sites for Acroloxlls coloradensis. Environmentai Informrtion: Merwmmtnt Count Mern StdError Minimum Mulmum TempaatUn (Oc) 7 18.57 1.26 14.00 24.50 Dissolved 01 (% Saturation) 7 69.71 6.22 44.00 90.00 CoQductivity (psieiaais) 7 148.00 27.5 1 76.90 284.00 Calcium (rnatre) 7 18.48, 3.70 8.92 36.76 PH 7 6.84 0.27 5.60 7.75

hrviourly tcc0Fded dbtribution h northern BC: Known only from 1 site (CU1981). Discussion: Acrolonr~coloradensis wu an UILCorrmYIn mollusc in northcnr BC king fouud ai oniy seven of 176 sites. It was fouad in both the Pacific and Arctic drainages and only in the imaior-type

ecapmvinces. It was found the Sub-Bord Spwe BGC zone* whkh bas a min mual tempaahne of 1.7 to 5.Rwith 4 to 5 months bclow OOC, md 2 to 5 mmths aôovc ltPC and with mual precipitstion

The range and the means of the envitohvariables for A. coloradenis are shown in Figure

-: -: 'Ibe habitats in which A. colom&nsis was fod did not incluâe those with water temperature >24.SD (Figure 2-Qa). Other t'actors ni- thai A. colorde~~~ismay k rcstricted to stable, percnnirt habitats (sec below) anci lowa temperatures may be characteristic of thse types of habitats. A. colomûénsrLP hs bccn previous1y dtscn'bcd as a cold water stenotherm (Brycc 1970) but the varicty of 124 habitats aad temperatures at which it was fouad in this study suggests that this may not be a valid descriptor of this taxa.

Dimlved Oxm: A. coloradensis was only coiiected fiam habitats of relatively high dissolved oxygen saturation (>40%; Figure 2-9b). Eurasian species of Acro1oxu.s are oxygendependent (Russell-Hunter 1978) and A. coloradensis may also be lirnited to well-oxygenated habitats. This may restrict the its distribution to perennial habitats with nlatively stable conditions.

Conductivitv and Calcium Concentration: A. coloradewis was coilected at a minimum calcium concentration of -10.1 mgIl calcium (Figure 2-9c). Howm, sites with lower meawes occuned only outside of the physical distribution range for A. coloradensis. Thus, it airmot k discaned if this calcium level is a minimum tequirement for A. coloradensir, if it is a remit of a range restricted by other factors, or if it is an ariifact of srnall sample size (n=7). fi A. colordemis is one of the fcw molluscs in this shidy found in habitats with an acidic mean pH, aithough it was found in allcaline codtions (Figure 2-9d). It may be that pemnhl, stable habitats within the range of A. colorade~~~istead to k &clic and tbat a pnfare for acidic wata is not a distinctive characteristic of the species.

Tkfdes were includcd in the Canonid Correspondence Anaiysis (CCA) dysis that includes A. colorude~t~is(Group 1; Figure 2-15), The dtsof this CCA are that the spccies are rcsponding significantly to the environmental wiables @ = 0.040) with 13.2% of the spccies pnseace munted for. A. coloradensis occurs on the plot most closdy EISSOCi8ted with lower than average pH, which is consistent with the obmtions hmthe range phof pH (Fip24).

Rior to this stuây, A. coloradensis was known only hmoniy one location in BC (Clarke 1981), that of Putden Lake, about 60 km cast of Prince Gaorge. As thcm wac very few Iocations for this mies in Cmnedr, it is a candidate for faderal daqpdspecies Listing with the Cornmittee on the Siahas of Endan@ Widlife in Cd(COSEWIC). Basai on ththe findings of this Jhdy in which A. colorade~~~iswu foimd a many new locations, many of which arc protected, and in a gregter range of habitat types than it was pmiousiy klicvd to lx capable of inhabiting, a recommendation for COSEWIC to list A. c01orade1~~i.sas "Not at Risk" has ben submined (Lee and Ackennan 1999c), in which a report on the cumnt status of tbis species is available.

A. coloradensts appears to k restricted to the southeast of the snidy am whac it was found only in the SubBoreai Spruce bioguxlimatic @ûC) nm This zone has a aean annual tempaahm above OOC and more months above lODC üim do the more noriMy BûC zones (Table 2-5). Howmr, if A. colomde11siswas fcstticted to the south of the study area by climatic requirements, it would be expected to plso OCM further south in the province but this has not ban vdedto &te. Fodevidence indicaîes that A. coloradensk was once more widesptcad in No& Ameh (Bryce 1970). As it is ccimatly most commody hown in western North America hmdisjunct locations in the Rocky Mountains (i.e. norihem BC, Montana and Colorado; Lee and Ackcmian 1999c), it may have survived glaciation in lakes in nunataks. Its cmtlimited distribution may refïect a limited capacity for post-glacia1 dispersal away hmthese small refugia altbough the possible location of these refugia bas not been examineci.

Clarke (1981) States that A. coloradensis is characteristic of mky, exposed portions of oligoîmphic and mesotrophic lakes, where it occm in shallow water on the undersides of rocks. In this study, A. .cdoradenis was collected hmrocks, submergeci wd,aquatic vegetation and submergecl deciduous leaves, and these coliections were somethes made in small, eutropàic ponds. These findings indicate that A. coloradensis cm inhabit a EZi greater range of habitats than was bclieved prior to this study. Fossaria galbana * (Say, 1825) Boreal fossaria

DRAINAGEAVATERSHED ARCTIC; Lirrd: Liard (2); Pace: Kiskatinaw (l), Peace (1)

Born1Plains: SouhAlberta Uplands (1) Narthetn Bord Mottntrias: Liard Basin (l), Northem Canadian Rocky Mountains (1) SabbrdInterior :Fraser Basin (1) BIOGEOCLIMATIC (BGC) ZONE Boreai White and Black Spruce (2) Spruce - Willow - Birch (1) SubB0rea.l Spruce (1)

Figure A4 - Coliection sites for Fmsaricl galh~.

TempcranirC Cc) 4 18.93 - 2.25 14.30 23.80 Dissolvd 02 (% Saturation) 4 74.00 7.72 59.00 91.00 Conductivity (psianens) 4 240.90 32.87 178.60 3 15.00 Calcium (mflitre) 4 34.58 4.90 25.29 45.63 pH 4 7.85 0.17 7.50 8.30 Previously record& dirtribution hi nortbern BC: Far er~tof nottbm BC only (Clarke 1981). Disc~siion: Fmsarirr galbtx~was an unccmmn mollusc in oaihan BC king founâ at five of 176 site. It wrs fodonly in the Arctic drainage in thm of the six ccapn,vinces. The thrce BûC zones in which it was found have mean mual tempcnams nnsipg from-3.0 to 5.Kwith up to menmonths bdow OOC ad up to five months above lODC and with annual precipitaîion mging hm 330 to 990 mm.

The range and means of the environninital miables mdfor F. galba^ are shown in Figure 2-10.

Tcmmatm: Figure 2-101 shows that E golboM was fodin relativtly hi& tanpaa~uehabitats (i.e., up to 23.m. F. gulba~is desaias a cold water specics (Clarke 1981), so it may be that it inhabits cook microhabitats withm the IIkes wha was fias oAcl cmly &eh wac coilected. Disrolved ~YCYP~R:Figure 2-10b shows that F. galbanu was only collectecl in habitats of relatively high dissolved oxygcn. However, as lynmaeiâs are ofien reliant on atmospheric air for respiration, F. galhno may be contined ta these babitats by otha fàctors adthat hi@ dissolved oxygen is an iatriasic feature of the large water bodies whae it was found. . Conductlvlty. and Calcium Concentrab'on: Figure 2-10c shows that F. galbanu was coliected from habitats with a minimum level of calcium concentration of 25.3 mg,a higher minimum calcium concentration than for most of the otha lymnaeiâs. It may k that F. gulbana is a calciphilic gastropod, restricted to habitats with high leveis of calcium (i.e. > 20 mg)= per Russell-Hunter (1978) although the small sample size (n=4) may not have allowcd for truc reprtsentation of its range of tolaaace.

Py: Figure 2-lod shows tbat F. galba^ was found ody in babitats with all

The results of the CCA ruc that the lymnaeid species are tespouding significantly to the envin,nmcntai variables @ = 0.010) with 6.3% of the spies prrseaee accounted for (Figure 2-16). The plot shows F. gulbana to be most closely co~clateûwith hi* than average pH. The sample sue for F. gafba~is small (n4) wbich msy pmait developmnit of a strong mimodal response, however, the above discussion suggests F. galbana may di&r ccologidy hmmost other lynmaeids ni that it was only collectecl at sites of altalint pH.

Tben an no known pmious rccds of the occumnce of E galbana in BC (Lee and AcLgman 1998% c). ClrrLe (1981) includa the far northezlsfan area of BC within the range of this spccies probably because it hiis ken colîectd hmthe Macka.uk Rnnr systm in Alberta ciid the North West Thtones (Ciarke 1973b). Wetb shdy extends the rcinge ofR galbono Mermst into BC, this range is still wiihin the MiicLcnnt River drainage cnd is sut of the Rocky Mountains. This Wbution su- that F. gulbanu migrateci post-gkially out of the Mississippi refuge ad was Mted hmfirrtha dispersal by the geographic Mer of the RocLy Moutab.

F. galbana is descnbed as bcing a cold-water @es occmhg ody in Wrcs and rivas (Clarke 198 1). Clarke (197%) States tht F. @boM is an indicator species of oîigotrophic anû mesotropbic Ues. Th cokctions of F. gulh in this shpdy were msde hm large lakes, which concurs with Clarkt's obSCNafiom.

*NO&: Referred to as Fwarùa &canpi by Cluke (19794 1981), Lymnuea decampi by Clarke (1973b), Lymnaea obllcssa dewnpi by Mozlcy (1938) anâ Golbo obmsa âècaypi by Baker (19 1 1). Fossaria modicella * (Say, 1825) Rock fossaria

DRAINAGEIWATERSHED PACIFIC: Fraser: FRW( 1);Stikine: Stiki~~(1) ARCTIC: Liard: Deue (2), Fort Nelm (2). Liard (1); Wss: Nass (1); Pace: Kiskatinaw (1)

Bord Plrins: Pace River Basin ( 1) C08d & hfoutltd~s:Nass Basin (1) Northern Bord Mountains: BO& Mountains and Plateaus (l), Hylaud Highland (l), Liard Basin (2) SabBord Interior: Fraser Basin (1) Tdga Pb:Hay River Lowld (2) BIûGEûCLIMATIC @cc) ZONE Boreai White and Black Spiuce (7) Figure A4 - Collection sites for FOSSUMmodicelk. Interior Cedar - Hemlock ( 1) Sub-Bo& Spnice (1) ,Environmentai Information: ,Memurement Count Mern Te~ti~et~nutO 8 18.80 Dissolved (% Saturation) Conductivi Siemens 51 1.09

7.66 hvioridy ~rdeddistribution b northern BC: Throughout noxthun BC (Ciarke 198 1). Discussion: Fossari4 modicella was an uncummon moliusc in norhem BC hgfod at nine of 176 sites. It was found in both the Pacinc and Arctic dninrges and in all ccoprovinces except the Central Interior. F. modiceIIa has ken coiicdcd in the Centrai haior outside of the stuây ara (La and Ackaman 1998b). The thice BGC zones in which it was found have mean annual temperatures mging hm-2.9 to 8.X with up to 7 mths bclow OOC rnd up to 5 months above lOOC ad with annual precipitation

The range admeans of th envUonmcntal variables measPred for F. nodicella TC show in Figure 2-10. Dissolved Ox~~gcFigure 2-lob shows that F. modicella was fod in habitats of relatively low dissolved oxygen (4W).However, as lymnaeiâs are ofien reliant on atmospheric air for respiration, the levet of dissolved oxygen in a habitat may k of limitecl importance in the ecology of this family.

Conductivitv and Calcium Concentration: Figure 2-lOc shows that F. modicello was coilected hm habitats with a minimum level of calcium concentration of 22.8 mg, a bigha minimum calcium concentration than for many of the other 1ymnaeiàs. It may be that F. modicella is a cakiphilic gasüopod, restricted to habitats with high levels of calcium (i.e., > 20 m@) as per RusselLHunter (1978).

N:Figure Zlûû shows that F. modicella was Eound only in habitats with alkaline pH. As high pH is associated with high calcium, the restriction of F. modicella to alkaline habitats may be due to its putative hi& minimum requirement for calcium.

The mdts of the CCA are chat the lymnaeid species are responding significantly to the environmental variables @ = 0.0 10) with 6.3% of the species presencc accountd for (Figure 2- 16). The plot shows F. modicella to be most cloeely correlatcd with higher than average conductivity. The above discussion suggcsts F. modicella may diffa cfologically hmmost otha lymnacids in tlns stuây in thai it was only collecteci at sites of reiatively hi& conductivity.

Clarke (198 I ) indicates that the distribusion of F. dicellu includes al1 of mrthem BC, which is consistent with the findings of this study. F. dicelia was not collectai ofken (n=9), but was found thmughout thc sndy am. This widcspnd distribution giva no indication of any barnas imposecl during post-glriai dispersion.

CW(1981) states that E rnodicellu occurs in pamnial laices, poads, sinsms, and in vanal . pools ad ditches, which comwith th fmdings of this stuây*

*Note: Refdto as Lymnaea modicella by Clarke (1973b) and Mozlcy (1938) and Galba humilis dicella by Baker (19 1 1). Fossaria pana * (1. Lea, 1841) Pygmy fossaria

Nl 1 1 1 (14 subsites within)

WIFIC: Fnwr: Fraser

SubBorerl Interior: Central Camdh Roclry Mountains

BIOGEOCLIMAnC @cc) ZONE Engelmann Spnice - Subalpine Fir

Figure A-7 - Coiiection site f;ar FOSSUMpana. Environmelitai Information: Mtruurtment Comt Mem Std.Emr Minimum Maximum Temperanire ("C) 14 12.10 0.94 7.75 17.00

------Reviously recordcd dbtribation in northern BC: Far cast only (Clarke 1981). Discuision: Fossaria parva was an uirommon moîiusc in northcm BC king found at one of 176 sites. Howcva, this one site reprtscnts a compilation of 14 records collccteû during m intensive stdy of one watashcd @wu Torpy Riva; sec Chpa 3). While that is a mge of environmental dies avriliible, they arc considaed to haw ben coliacted only at one site (NI1 1 1). This one site is in the Pacifk drainage, the subBoreal Interior cc~pfovinctanci the Engelmann Spnre - Subaipine Fir BGC zone. This BGC zone bas a man innurl tempaitun of-2.0 to 2.0°C with 5 to 7 months klow OOC and O to 2 moPths &ove 1OOC and with annurl precipitatim canging hm400 to 2200 mm.

The range anà mean of the environmatal variables mcamred at the 14 locations within this one site are hwnin Figure 2-10. F. pmvui was fouad most commonly assoeîated with dsaepmr, that had bccn impadcd by the constniction of access mpds for timber hnma. These Iotic locations are uniike auy of those sampled during the course of the study mai in Chapta 2. The collections of F. parva , were also made eariier in the samnthsn were the coiicctions for the Chspter 2 midy. The diffme in 131 these lotic, early season locatioas is reflected primarily in the temperature, of which the mean is significantly Iowa than for most of the other lymnaeids in this study (Table 2-7).

Temeratm: As discussed above, the coliectious of F. pmwere made earlier in the season than mst other collections in this study. This secms to be nfîected in the water temperatures recorded for this spies as Figun 2-1Oa shows the temperature range for F. pmo to have a much Iowa maximum tban those ranges for the 0th- lymnaeids in this study.

Dissolved Oxynen: Figure 2-lob shows that F. pana was collected in habitats of felatively high dissolvcd oxygen. F. pana is an amphibious species (Clarke 1981) and, as a lymaaeià, wodd genetally be reliant on atmospheric air for respiration. The higb measures probably reflect the higha levels of oxygen expected to k found in the cooler water temperature locations rather than an ecological requinment for F. parva.

Conductiwty. . aad Calc ium Concentration: Figure 2-10c shows that F. parva was fouad at calcium concentrations with a minimum of Il .O mgll. Few sites within the am in wbich F. parva was collected bave lowa conductivity/calcium values tban tbis, therefore, this may not represent a physiological requircment for F. pana but mther the minimum conditions witbin the only area in which it was found.

: Figue 2-lûd shows thas. unlite the otha Fossaria pics coiiected in this stuày, F. parva was found in habim of both acidic ruid dkabconditions so that its mean pH is signifcantiy lowa than for F. galbanu and F. nodicella (Table 2-7). This tolance for acidic pH my be in keeping with the putative lowa calcium requircnicnt for F. pana than for F. galbana anci F. dicella.

nie resuits of the CCA are thst the lyiimrciâs rcsponded significantly to the cnviro-ta1 variables (p = 0.010) with 6.3% of the piespmcnce rccorwcd for (Figure 2-16). The plot shows F. parwu to comspoad most closely to lowu hmaverage tempmturc. As abow, the mesa taapentm at which F. powa was coiîectal was signifidy lowa than tbat for mst other lymnacids in this stuây.

Then arc no previous records of F. pm in BC (La and Ackaman 1998a, c). Clarke (1981) probably includes northtastem BC within its range basai on coilcctions hmthe Mackenzie River systcm in Alberta and the M. in this snidy, it was fond in the Pacific drainage hmthe Fraser Riva watcrsbad ucteading the range of F. pcuw hto BC cird mio an arca wcst of the Rwky Mountains.

Ctarfre (198 1) states thit F. prw is amphiiious ad lives on wd mud flats, kshom and riva bariLs near the wata's dge, and in mushes. The locations whae F. prvcr was colected in bis shidy are consistent with this prcviously recordai ecology.

*Note: Rtfdto as Lynuioea prva by Clarke (1973b), Lynuiaea porw sterkii by Mozely (1 938) and Galba pwo by Baker (191 1). Lymnaea atkaensis* DaU, 1884 Frigid lymnaea

ARCTIC: Lhrd: Dase (3), Liard (1); Pace: F~Y(1)

Northtrn Bord MOIUI~~S:Liard Basin ( 1), Northcrn Canadian Rocky Mountains (l), Bord Mountains and Phücaus (3)

BIûGEûCLIMATIC @cc) ZONE Bord White and Black Spnice (3) Spruce - Willow - Birch (2)

Figure A-8 - Colleztion sita for Lymmea athemis. Environmental Information:

Dissolveci Q (% Saturation) 2 82.00 2.00 80.00 - 84.00 Conductivity (pSiancns) 2 360.00 115.00 245.00 475.00

ReVIOPsly mordcd distribution in northtm BC: Northwcst only (Cluke 1981). Discussion: Lymnuea atkueash was an ummmon milusc in &cm BC king found at five of 176 sites. It was foimd ody in the Arctic drainage anci only in the Northem Bord Mountains ecolprovince. The two BGC zones in which it was fdhave mean annuai tanperatures of -3.0:to 2.W with up to 7 mmthp klow ODC and up to 4 months above lOOC lad with annual precipitation mghg hm330 to 700 mm.

L. atknsis was colîected hmtwo ecologicai sites. Tbt mge and mcans of the enviro~tal variab1es maadat these two sites arc humin Figun 2-10.

Tmyratw: Figure 2-1Oa shows tht L. otkremis was cdkected at low tempera~tnsnlitivc to othcr lymnaeids in this study. L. athemis is rcsfncted to thc bir northwcst of the study am whae it has only been collecad âom lakes. Low temperahm may be indicative of these habitats ratha then of a physiologîd requircmait of this species. Dissolved ûxym Figure 2-lob shows that L. atkoemis was found in habitats of hi& dissolved oxygen. However, as lymnaeids generally niaintain a dependence on atmospheric air, it is not expected that their distributions may be limited by the amount of dissolved oxygcn in a habitat.

Conductivitv and Calcium Concentration: Figure 2-IOc shows that L. utkaensis was collected hm habitats witb bigb levels of dissolved calcium (35.2 mgll minimum). ït may be that L. utkaenris is a calciphilic gasüopod, restricted to habitats of high calcium concentration (Le., > 20 mgil) as defiaed by Russell-Hunter (1978).

Figure 2-lûd shows that L. utkaensis was collected ody at sites of alkaline pH. As WinepH ami high calcium levels are relateci, this niay be in keeping with its putative high calcium rquirement.

The resuits of the CCA are îhat the lymnaeid species are responding significantly to the environmental variables @ = 0.010) with 6.3% of the piespresence 8ccounted for (Figure! 2-16). The plot shows L. utbensis to bc associatcd with bigha than average dissolved oxygen. The small sample sue (n = 2) does not dow developmait of a uEimodal cespoase to any particular variable and the level of dissolvcd oxygen is probably of limited ecologicai conseQuenceto this smes.

L. athemis is known ody fmm Aiaska and northwest Cana& (Bmh 1989). Prcvious to Clarke's northan BC meys, L. at&ue~isappcw to have bem known only hmthe Aleutian IsW (Moijely 1938, Baker 19 11). L. aikensis was found only at two sites during thU shdy, oncc hmthe same Ir*e hmwhae thae were pmious records @ew Lake) and dso in a new looation in a lake in the same major watashd (Liaid). Accurding to Clarke (1981), L. atkuensis is a &nngian relic spccies and the resuîts of this study are in accodmce with that assaurmcnt. L. atheksis displays a vay resûictai

distribution tbit connas with hypothcsizad dispasal mutes for hshwatu fi& hmthe Berhg Refuge * (McPhaii ad Lindrey 1970).

Cb(1979) states tbat L. utbe~~~isis knoum only hmoligotiophic laLes but in tbis shady was collected in one iake with abundant vcsetption. Clarkc (1981) dcscribes L. atkoemis as occPmng on mcks and among sparsc submased vegetation. At the two ccologicaî sites at which it was coliected in this study, it was obmed actively crawiing thnrugh soft oubswes addmg.additional information to the previousiy recotded ccology. Lymnaea stagnaüs appresssa* Say, 1821 Swamp lymnaea

SmS(33): NiOOl,NlOlO,NlOl5,NlO2O,N1033, N1037,N1038,N1042,N1043,N1048,N1052,N1053, N1055,N1056,N1058~1059,N106O,N1062,N1069, N1072,NlW l,Nl096,N1097,NllOS,NllO7,NO 135, N0137,MN1000,MN1001,MN1004,MN1010, CN1012,CN1016 DRAINAGElWATERSHED J'AClFIC: Frrser: Frscn (2), Nechalto (1), Stuart (1); Skeena: Babiilc(2), Skma(1); Stikine: Srilriae (2); Yukon: Ath(1) ARCllC: Lhrd: Deaac (Q), Fort Nelson (S), Liard (6); Mickenzfc: Hay (1); Pace: Berna (1), Peace (31, Pine (a, smolry (1)

Boml Pidns: Central Alberta Uplands (l), Soutbm UplaW (4) -Cmd & Mountains: Nass Ranges (1) Northem hdMoPo~~~s~ Liard Basin (\O), A-9 stagnalis Figure - Collection sites for Lymauea BodMoutains and PIateaw (3) BIOGEOCLIMATIC @CC) ZONE SubhrdInterior: Fraser Basin (8) Bonal White aud Black Spnice (24) Tdg8 Phhs: Hoy Riva LowU(l), Nonhern Interior Cedar - Hemlock (1) Albmta Uplands (2), Hay Riva LowW(3) Sub-Boreal Sprue (8)

Temperanire (OC) 25 19.48 0.62 - 14.00 26.20 Dissolved 02 (% Saturation) 25 72.44 3.40 25.00 98.00

Calcium (mfltre) 25 39.54 4.38 12.13 10 1.54 pH 25 7.5 1 0.161 5.601 8.90 Reviously rceorded chtribution h nortLtrn BC: Throughout northem BC (Cîarke 198 1). Dkursion: Lmeastagrurlis oppressa is a common mUusc of hemBC kmg fouad at 33 of 176 sites It was found in both the Pacific and Arctic drainages and in aU ecoprovinca except the Central Intaior. This @es has ken collectai in the Ceimal Intcrior outa& of the study arce (Lee and Ackerman l998b). The three BGC nncs in which it was found have mem muai tanpaahues nnging firom -2.9 to 8.X with up to 7 montbs klow 0.c ad up to 5 mntbs above lOOC aod with muai precipitation ranging hm330 to 120mm. Temperature: Figure 2-1Oa shows that L. stagnalis appressu was found at temperatures >2S°C suggesting that tcmpashms may not be a limiting factor in the distribution of this species.

Dissolveci Owm: Figure 24Ob shows that L. stagnalis appresso was found over a wide range of dissolved oxygen. As lyrnnaeids gencraiiy maintain a depenâence on atmospheric air, it is not expected that theu distributions my be iimited by the amount of dissolved oxygen in a habitat.

Conduetivitv and Calcium Concentration: Figure 2-10c shows tbat the minimum caîcium concentration at which L. stagnalis oppressa was collected was 12.1 mg& As there wae lentic habitats with Iowa conductivity/caicium levels, this may represents a minimum calcium repuirement of a habitat for L. stagnafis oppressa. pH: Figure 2-lûâ shows that L. stagnulis appreSSO was collected over a vay wide range of pH in both acidic and altaline conditions. This suggests that pH may not be a limiting factor in the distribution of lhis specia in northem BC.

The resdts of the CCA m that the lymnaeid opccies an responding significantiy to the environmental variabla @ = 0.010) with 6.3% of the spccies pmence accounted for (Figure 2-16). On the plot, L. stagnolis appresa occurs between hi- than average tcmpnanm auâ higher than average pH, dthough it is btcdclose to the origin. The above discussion does not indicate that 4thr of these variables is of particuiar cco10gid importance to L. stoplis uppressa.

Clarke (1981) indicatcs that the àisüibuîion of L. s~ripIkoppressa includes aU of mrthem BC. This coacun with the nndings of this shdy whac L. stagnulis appressa was foimd thmugbut the shuly arca. ThW widcspreaâ distriiution gives no indication of any barries c11c0unî~during postglirid dispcnion.

Clarke (1981) statcs that L. stagnulis oppressa aentrs in ail panmial-water vcgctatcd habitats and that it is an indicator @es of eubopbic wata Mes(Ciarke 197%). h this study, it was always coîîected hmvegctatad snss in Mes, ponds, swamps or slow seesnis, which comwiîh Clarke's statcmcnt.

*Note: Rcferred to by Clailre (198 1) and Mozlcy (1938) as Lymnaea stagnalisjugirlurts. Lymnaea sp.

SITES (1): MNlOOO

DRAINAGWWATERSHED PACLFIC: Yulron: Ath ECOPROVINCE/ECOREGION Northern Bortrl Mountains: Boreal Mountains and Plateaus BIocEocLIMATIC (BGC)ZONE Boteal White and Black Spruce

I Figure A40 - Collection sites for Lymnaea sp.

This coliection, identifiai only as Lymricrea sp., bas been iacluded as it is one of the few records for Wwater molluscs for the Yukon watershed in BC (Taylor 1993). Althougb it is identifid as Lyllllt~eup. it is wt possible to determine to wbat gcnus tbis collection may klong as Dr. Dwight Taylor, who cxBmitled these specimais, identifia mwt m4mkrs of the Farnily Lymnacidae as belonging to the gews Lymmea (e.g. Taylor 1993), whaeas othm authors subdivide this gaws iato -y gcnera (e.g., Fossmio. Stugnicola, Lym~ea),which is the nowachused in this study. Stagnicola arctica * (i.Lea, 1864) Arctic pondsnail SITES (26): N1012,N1020,N1029,N1033,N1035, N1036,.N1041,N1062,N1067,N1068,N1071~1096, N1097,N1103~110d,N0128,N0130,N0133,CN1001, CN1ûû3,CNlOOS/MNlOll,CNlûû8,CNlûû9,CNlOlO, MNl003,MN1009

DRAINAGEAWATERSHED PACIFïC: Fnm: Nechako (l),Stuart (2); Skrcm: Babirsc (2); Stfldnt: Stikk (1) ARCTIC: Liard: Deiue (S), Fort Nehn (4). Keehilca (2),Toad (1);Mickende: Hay River (1);Pcict: Beatton (2), Finlay (2). Pine (3) ECOPROVINCEIECOREGION Born! Plains: Central Alberia Uplands (1),Muskwa Piatcsu ( 1), Peacc River Basin (1), SouhAlbeira UP~(1) Centrrl Interior: Ftiuct Plateau (1) Northern Bord Mountains: Lîard Basin (1), -. -. .- ... .-. I Noriheni Canadian Roch Mountaias (S), Bonal Figure A-1 1 - Coilection sites for Sta~icolaarctica. Mountains aod Piat.nun (8) Sub-Bord Interior: Central Caaadian Rocky Mts. BIûGEOCLlMATIC @CC) ZONE (l),Omineca Moutaiirs (l), FmBasin (3) Bomi White and Black Spruce (15) Tilp Moi: Hay River Lowland (3), Noribcm EngeIrmuui Spiuce - Subalpine Fu (1) m- UP~(2) Spm- Wüiow - Bir& (5) Sub-Bord Spnict (5)

Dissolved O, (% SInaation) - 15 58.60 6.37 15.00 89.00 Conductivity (~Sianens) 15 264.1 1 45.77 19.70 690.00 Calcium tmdiitre) 15 38.04 6.82 1.60 101.54

Revioasly recordcd dhtribution in northern BC: Far north ody (ClsrLe 1981). Discussion: Stagnrcola arctica was a common moilusc in northem BC kgfound at 26 of 176 sita. It was found in both Pacifie and Arctic drainages and aîi of the ecoprovinces except the Coast d Mountains. The four BûC zones in which was fodhave man annuai temperatures mghg 6rom -3.0 to 5.W with up to 7 months below 0°C and up to 5 months above WCand with annual pmipitation ranging hm330 to 2200 mm.

The range d means of the enviromenta1 variables messimd at the sites whae S. arctica was collectai are &on in Fi- 2-10. TVFip2-LOa shows that S. arctica was found at temperatures >2S°C suggesthg that temperatures may not be a limiting factor in the distribution ofthis species in northem BC.

Dissolved ûxvm: Figure 2-lob shows tbat S. arctica was foimd over a wide range of dissolved oxygen. As lynmseids genaally maintain a dependence on atmospheric air, it is not expected that their distributions mny be limited by the amount of dissolved oxygen in a habitat.

Conductivitv and Calcium Concentration: Figure 2-10c shows that S. arctica was found at the minimum conductivity/calcium concentration measdin this study. This suggests that the conductivity/calciumof a habitat may not be a limitiag factor in the distribution of this species. a Figun 2-1Od shows that S. arctica was found ova a wide range of pH in both acidic and alltaline conditions. This suggests that pH may not be a limiting factor in the distribution of this specits.

nie mults of the CCA are that the lymnaeid pies are responding significantly to the environmental wiablcs @ = 0.010) with 6.3% of the species presence accounted for (Figure 2-16). On the plot, S. arctica currtsponds mort closcly with lown than average dissolved oxygen. As lymnaeids are gendy reliant on atmosphaie air, this placement on the plot may be of limited ecologi'cal importance.

Clarke (1981) describes S. arrtica as an arctic and subantic Jpecics occuning only in the faf uorth of BC. Thlp hdy foiiad arcticu to k distriiuted ratha consistdy throughout the study ana, so tbat the limits of its distribution are mucb hiither south than those indicatd by Clarkc (1981). S. arctica was mt coiiectcd ncar the cuast of northem BC (Le., in the Coast 'and Mountains ecoprovince) whae the climite is milda, so it may indeed k the coldadrpted arctic to subactic specics descn'bed by Clarke but with a mmswthdy distribution thn pmiously cecordai. Accordhg to Clarke (1981), species with a subiuctic distribution are not nccasarily considered to have dupased hmghcial nfiigia but ratha hmadjacent regions to the south anâ ndld adapted spccics myhave moved south adthen north with advancing and rrtreetiag ice sheets. S. mtica appcw to k such a species although its cumntly hum distribution docs not indicated if it hs repapuiatd mrthem BC bm only the Mississippi Refbge or hmthe Mcas weîî.

Clarke (1981) statcs that S. arcticta ocmas in Mes, ponds, rivers, sciimc, ditches and muskeg pools which is consistent with the habitat types in which it was found in tbis study.

*NO&: Refdto as Lym~eaarctica by Ciarke (1973b) and as GuhvaMi arctica by Bakr (191 1). Stugnicola caperata * (Say, 1829) Wrinkled marshsnail

DRAINAGEJWATERSHED mcTIc: brd: Fort NeLon (1); P#cC Kiskatinaw (l), Pace (l), Smoky (1)

ECOPROVINCEtECOREGION Bonli) Plah :Pace River Basin (l), Southcm Albcrta Upld(2) Tdp Pbs: Hay River Lowland (1)

BIOCEOCLIMATIC @CC) ZONE Bord White and-BlackSpmce (4)

Figure A42 - Collection sites for Siugnicola caperata.

Environmentaï Information: w

Tcmpcranirt (OC) 3 20.13 2.48 16.W 25.00 Dissolved 02 (% Saturation) 3 47.33 20.27 - 7.00 7 1.O0 Conductivity @Siemens) 3 656.97 455.76 175.90 1568.00 Calcium [mfltre) 3 96.62 67.95 24.89 232.45 r

Reviotasiy mrded&tribotion h northtrn BC: Not prcviously recordcd (Clarke 1981). Discuarion: Stagnicola caperata was an urrommon moiiusc in mahm BC being found at four of 176 sites. It was found ody in the Arctic drainage in the Bureai Pbd Taiga Plains ecoprovhces, east of the Rody Mountains. nie BKin which it was fouIIcf bas a mean annual tempemtm of -2.9 to 2.W with 5 to 7 months below OOC and 2 to 4 months above 10°C and with annual pncipitation ringing hm330 to 570 mm.

The range and mans of the enviro~llll~~ltaivariables mcaaaed at the sites where S. caperata was collectai are shown in Figure 2-10.

Tm:Figure 2-1Oa shows that S. ccrperata was fouad at tcmperanires up to WC suggesting tbst hi& mer temperanne mey not be a limiting fDctor in ibe distn'bution uflbis species in aorthem K. Dissolved ûxypc~~:Figun 24Ob shows that S. caperata was fouad ova a wide range of dissolveci oxygen. As lymnaeids generally maintain a dependence on atmospheric air, it is not expected that their distributions may be limiteci by the amount ofdisçalved oxygen in a habitat.

Conductivitv and Calcium Concentration: Figure 2-lûc shows that S. caperuta was coUected only in habitats where the concentration of dissolved oxygen was greater than the 20 mg/l useâ by Russell-Hunter (1978) to classify Grshwater molluscs as calcipbiles. However, the sample size for S. caperata is small (n = 3) and the range measured niay nnt be tdyrepmentative of the minimum calcium requirement for this species.

Figure 2-lûd shows thai S. caperata was only collected hmhabitats of almost neutmi (6.95) to alkaline pH. Alkaline pH is relateà to hi& calcium concentration and, as discussed above, it may be that the small sainple size for S. caperata dasaot give tnre representation of its range of tolerance to pH.

The results of the CCA are that the lyianaeid species are responding significantly to the environmentai variables @ = 0.010) with 6.3% of the species pr*lare accounted for (Figure 2-16). On the plot, S. cuperata corresponds with higha than average conductivity. The sample size fbr this species is d (n = 3), which das not allow the fôrmation of any strong unllnodal response. Howeva, as discd above, cmdudivity/calcium concentration msy be an important ecological fsctor for S. caperata in norkhcm BC.

Clarke (1981) indiates that the watem limit of S. caperuta in Canada is west ccnüal Albcrta. The distribution of S. crrperata fomd in tbis stuây di&R somwhat hmtbat indicated by Ciarke. The pre~e~:eof S. caperuta on the Boreai Plains in BC is jurt a siight extaion west of its know distniution in Alberta and tbis is whae most of the collcctions wcre made. However, an additional collection was made in the Taiga Plains nair Fort NeIsoa, which extends the range of this specics to the north. However, S. caperuta is stiU only boum in Canada hmcast of the Rodry Mountains. With the distribution as illustratd by Clarke (1981) and this new Monnation, it wddapperr that the post-glacial dispasil of S. capota ans hmthe Mississippi Rduge ancl its continucd dispasal I& have ken impeded by the geogtaphic buna of the RocLy Mountains.

*NO@ Rcfdto as Lym~eacopérata by Taylor (1981), ChiLc (1973b) ad Morley (1938) and as Galbu caperuta by BaLer (19 11). Stagnicola catascopium catascopium * (Say, 181 7) Woodland pondsnail

SITES (7): NI107, Ni1 10, NI 113, ~0106,~0109, NO1 14, MN1006 DPAGENATERSHED PACIFIC; Fraser: Fraser (3), Nechako (3) ARCTIC; Peact: Omintca (1) ECOPROVINCE/ECOREGION SubBored Interior: Centrai Caaahian Roclcy Mountains (l), Omineca Mountains (l), Fraser Basin (5) BIOGEOCLIMATIC @cc) ZONE Bonal White and Black Spnice (2) Sub-Bod Spnre (5)

Figun A-13 - Collection sites for Stupicol cat4scopium Environmentai Information: Memunment Count Mean StdError Minimum Mulmum , Terllpmm (OC) 3 16.03 4.42 9.60L 24.50

Previousiy recordcd dlitribution hi nortbern BC: Absent hmthe northast (Ciarkt 1981).

sevm of 176 sites. It was fouad in bth tht Princ and Arcâic drainages d only in the Sub-Bord interior ccopi~vince.The two BGC zones in which it wufoupd bave mean a~ualtesnpartianr of -3.0 to 2.00C with up to se~nmonths klow OOC ad up to 4 mnths above lOOC and with annual pmipitation ranging hm330 to 70mm.

The range and meaas of the environmental variables meiisiircd for S. catuscopium catuscopium sn show11 in Fi- 2-10.

Tm:Figure 2-10s shows that S. amtica was fodat t-. up to 24.5OC suggestiag that tempganrrc~may not k limiting -or in the âisüihuîion ofthis species in oorthern BC. Dissolved ûx- Figure 2-lob shows tbat S. cutascopium catascopium was only found in habitats of high dissolved oxyga~ As lymnaeids generally maintain a dependence on atmospheric air, it is not expected that theu distributions may be ümited by the amount of dissolved oxygen in a habitat.

Conductivihr; Figure 2-10c shows S. catmcopium cataccopium was collected ova a vny Wted range of conductivity/calciirm concenüation with a minimum of 16.6 mgil of calcium. Howeva, the sample size for S. catascopium catascopium was sd(n=3), and range measund may not give a hue representation of the minUnum calcium requirement for tbis species. a Figure 2- 1Od shows that S. catascopium catascopium was coliected hma range of pH that includes both acidic and alkaline conditions. This suggests tbat pH may not be a iirniting factor in the distribution of this specia in noitbem BC.

The rdts of the CCA are tbat the lymuaeid species are fesponding signifîcantly to the enWonmentai variables (p = 0.010) with 6.3% of the species presence accounted for (Figure 2-16). On the plot, S cutuscopiiw, cutuscopium corresponds most closely to Iowa thsn average conductivity. Howcva, the saInple sizt for this spccies is sniall, wbich piohiiits formation of the rcquisite unimodal rrsponse rrquireâ for ecological intupretatioas to be made hmthe plot.

TIM dyfound S. catascopium catmcopium to bave a much more hteddistribution than that indicated by Clarke (198 1). Ciarke records S. catarcopium catmcopium as occurring thughout northem BC exccpt for that ana in the northwcst inhabitai by Lymmea atAaensis. A sesrch of mweum records (Lee and Ackemm 1998a, c) fouonly one ncad for S. colpccopium cat~~~copiumfrom m&an BC, at site MN1006 (- Lake) which is the most wrthaly point on the rnap included hm. Clarke's extdeddistribution kyonâ thelocations may be speculativt basai on this qccics preJeDce elsewhere in watcrshcds which extend mto BC but this is not supportai by the firrdings of this stuây. The distribution of S. c~tascopium~copim butd on this study and as givcn by Clarke (1981) indicate thas cat4scopium catascopium pbably moved into mrthan BC hma southcm refuge such as the Mississippi.

Clarke (1981) states htthe most fiapcnt habitat of S. cutmcopium catascopium is on rocks exposai to wvcs or currmts, dtûough Clarke (1973b) dcscnbcs a more varied coology for this specics with mks king a prominent featurc in only 10 of 27 coiicction sites. Clarke (197% statcs that S. catuscopiiwn cutuscopiim is indicative of oligotrophic ad maotrophic laka. h this whik S. catuscopium cutuscopium was collectai hmrocks in a riva, it was gcndycoUected hmthe sballow edgcs of oligottophic to mcsotrophic Llas which COIICU~Swith Clarke's listing of S. cutuscopium catmcopiwn as an iidicator specits of thcse trophic lmls. *Note: Refdto as Lym~eacut~~~copium catascopiwi by Clerke (1973b, 198 1). Otba wohs on the Family Lymnaeidae refer only to Stagnicola catnrcopium (Turgw et al. 1998, Burch 1989). Clarke (1973b, 1981) identified scvd subspecies and tbis nomenclature has been used in this stuây as the subspecies found in BC appeam to k quite distinct from the othas described by Clarke. 0th- works refer to Lymnoea cat4scopium (Baker 1938) and Galba catuscopiwn (Baker 191 1). Stagnicola elodes * (Say, 1821) Marsh pondSnail

DRAINAGWATERSHED PACWIC: Frrwr: Fr- (l),ïü~hh(s),s~ (3); Sk~ari:Bab* (2), Buikley (2), Skna(1) S-t: Stikine (3) MCTIC; Liard: Dease (9), Fort Nelson (1 1 ), Kechika(l),Liard (4),Toad (1); MacIrenzit: Hay (2) kct: Finlay (1). Kiskatinaw (1), Pannip (l), Pcact (7), Pine (2), Smob (2), Beatton (3)

Figure A44 Collection sites for Stngncda elodeS. - Bord Plriiu: Central Alberta Uplends (2), Peace River Emin (4), Soutkn Aiberta Upianàs (5) BIOCEOCLIMATIC 0UlNE Ceatnl hterbr: Fraser Plateau (7) Bord White and Black Spnice (41) Cout 4 MomCriai: Naa Basin (1) Interior Cahr - Hdack(1) Notthm BordMomtriar: Hyiand Higihd (l), Spnice - Wdow - Birdi (3) Northcrn Canadian Rocky Mountains (4), Liard Sub-Bord Spnw (17) Basin (7), Bottai Mountains and Pintmiil9 (8) SiibBoiwl Interior: Fraser Basin (9),Ceaoal cadianRocky Mountains (2) TmPlah Hay Rinr hwland (3), No- ,Environmentai Information: AbtaUpW (3), Hay Riva LowW(6) Mururement Count Mea StdError Minimum Mhum Tanperatiirc (OC) 46 18.63 0.59 10.40 27.20 Dissolved 02 (% Saturation) 46 71.61 3.26, 23.00 135.0 46 296.50 32.88 76.90 1 199.00 Calcium (rnfltre) 46 38.44 4.42 8.92 159.73 pH 46 7.50 0.1 1 5.60 9.00 Previouaiy neorded àistribution hi notthern BC: Thmugbout mrthera BC (Clarke 198 1). Diwuasion: Stagnico1a elodes is one of the vuy cornmon mliuscs in northem BC king found at 62 of 176 sites. It was fdin both thc Pacifie adArctic drainages and m d of the northsn ecoprovinces. The four BûC zones in which it was fdhave mean average tcmperatures ranging fkm -3.0 to 8.7T with up to 7 monîhs beiow 0.c and up to 5 months ahove 10Y: and with annual prccipitatim ranging hm330 to 1200 mm- The range and means of the environmental variables measund at the sites where S. elodes was collected are shom in Figure 2-10.

Tem~eran~e:Figue 2-lOa shows tha! S. eloda was found at temperatures >25T suggesting that temperatures may not be a limiting factor in the distribution of this species.

Dissolved Oxvm Figure 2-IOb shows that S. elodes was aot collected in habitats of exftemcly iow dissolved oxygen saturation. However, as lymnaeids generally maintain a dependence on atmospheric air, it is not expected that theh distributions may be limited by the amount of dissolved oxygen in a

, habitat.

Conductivitv and Calcium Concentqgjon: Figure 2-1Oc shows tbat shows that the minimum calcium concentration a which S. elodes was collecteci was 10.1 m@. As then is a relatively large -le size for this species (a=*, this minimum amount rreonled may rcpresent the minimum requirement of a habitat for S. eldks.

Figure 2-lûd shows that S. elodes was foui over a wide range of pH in both acidic and altaline conditions. This suggests that pH may not be a limiting factor in the distribution of this spccies.

The mults of the CCA an that the lymnaeid pies an tesponding sigaifcantîy to the environmclltal variables @ = 0.010) with 6.3% of the @es prcsence accountd fol (Figurc 2-16). The plot shows S. elodes to occur near the origin of aii the ~vironmcntaivariables ad comspond to no particular vanable.

Clarke (198 1) indicaies thst thc distribution of S. elodes includes al1 of northem BC anâ thai it is found in dl kinâs of aquatic habitats. This distnbution anci ecology is in accordSnce with the findings of this saidy. This widespreaû diainbution gives no evidcnce of any barnas imposed during pst-gkial dispersion.

*Note: Refdto as Lynvtciea el& by Clarke (1973b), Lyninrieu pulwnur by Mozdy (1938) and Galba el* by Baker (191 1). Stugnicola sp. - juveniles SITES (5): NlO52, N1072, N1074, NlOSO, NO1 10

DRrnAGE/WATERSBED PACIFIC: Fraser: NecluLa (1): Nus: Menndin (1); Stildne: Stikinc (2) ARCTIC: Lhrd: Lisrd (1) ECOPROVaVCE/ECOREGION Centnl Interior :Fraser Plateau (1) Comt & Mountrio~:Nass Basin (1) Northern &rd Moun- Liard Basin (1), Bortal Mountains d Piateaus (2)

, BIOCEOCLIMATIC @CC) ZONE ' Boreal White and Blad: Spnice (3) Interior Cedar - Hemlock (1) SutFBoreal Spruce (1 )

Figure A-15 - Collection sites for Stagnicola sp.

Environmental Information: +

Temperanirr (OC) 4, 18.75 1.22 15.30 20.60 Dissolvecl (% Saturation) 4 8 1 .O0 10b67 50.0. 98 .O0 Conductivity (psiuncas) 4 252.73 68.09 119.10 435.00 Calcium (Wlitn) 4 32.56 9.15 14.60 57.05

Discussion: SpscimePs of the Family Lymnaeidae îhat are las dian 10 mm in height and have less than four whorls are jweniles of the genus Stugnicola (Ciarkt 1973b). When juveniîcs wac coliectad with adult spccimns in this study, the two wae combined. The five records hcluded bae rn for sites whne only

The range and means of the aivitolllll~~ltalvariab1es meaaaed at the sites whae S'ugnicola sp. jwaiiles wae colle*cd are shown in Figure 2-10. This table shows btthe ranges aud meuis for these juveniles or diff~n~thm thosc of any of the othcr Slligncola species so they cannot be tciitatively idcatificd by th& affinity with the range of the mwpnasental variable for otha species. As they csna~tbe iRaitified to spies, the mtrimrrma*i of ~11viro1ll1l~1ltalvariables MU not k fûrther

The CCA plot shows Skzgnicoia op. jwdes to corr~spondmost closeiy to hi- tban average pH. This Qcs not sam to k a particuIarly miportant ccological factor for this taxcm. Aplkxa elongata * (Say, 1821) Lance aplexa

1 DRAINAGEIWATERSHED PAC- Skeenr: Babh (2) ARmC: Lhrd:R Nelson(2); Peace: Smoky(2) ECOPROmCmCOREGION BordPlains: Southcm Albcrra UpW(2) SuMoml Interior: Fraser Basin (2) Tdga Pb:Hay River Lowld (2) BIOGEOCLIMATIC @cc) ZONE Boreai White and Black Spruce (4) Subgoreal Spnre (2)

Fi- A46 - Collection sites for Apia elongata. Environmentai Informatioa: Merrmment Comt [MC= Std, Emr Minimum Temperahire ("C) 3 18.93 1.88 17.00 Dissolved 0,116 Saturation) 1 3 51.33 14.33 31.00 Conductivity (~Siai~ps) 1 3 1 181.731 88.651 90.30

Rwiouaiy nconkd dirtribntion in northern BC: Throughout mrthern BC (Clarke 198 1). Discusr ion: Aplera elongata is an unconmon mllusc in northcrn BC bcing found at six of 176 sites. It was found in both the Pacific anâ Arctic drainages anâ in three of the six ecoprovinces. 'Ih tao BGC zones in which it was fodhave mesn muai tcmpctanrrc~mghg hm-2.9 CO 5.K with up to 7 months below OOC ad up to 5 months above 1OOC and with smnial prsipitaîion ranging hm330 to 990 mm.

The range and means of the environmental variables meanacd at the sites what A. elongata was coliected are shown in Figure 2-1 1.

Tcmpashnc: Figun 2-1 la shows tht A. elongutu wcs fomd ody a tempmtms up to 22.PC. Howevcr, the tudl sarnple size of this taxa (n=3) may mt give an adapte -on of its mie range of tolanace to hi* watn temperatm. Dissolvcd Oxvm Figure 2-1 lb shows that A. elongata was not found in habitats where the dissolved oxygen was vay low. However, as physids geudly maintain a dependence on atmosphaic air, it is not - expeaed that th& distributions may be limited by the amount of dissolved oxygen in a habitat.

Couductivity and Calcium Concentration: Members of the Physidae were not coliected in the habitats of the lowest conductivity/cPlciumconcentration rneasured in this shdy (Figure 2-1 Ic). The minimum level at which A. elongafawas collected was 12.1 mg/& However, the srna11 sample size (n = 3) may not give an adequate representation the minimum calcium quirement of this species

p& p& Figure 2-1 1d shows that A. elongata is one of the few gastropods in this study with a mean pH les than naitral(7.0). This mean is significantiy lowa than that for Physa sknneri @=0.015) and the ranges of the two species do not ovalap. This suggests that these two spezies may be separated ecologically by the pH of a habitat. Howevn, the sample sizs for both of these species is mai1 (n = 3 and n = 4) and these values may not give an adequate represcntation of the true ranges of tolaaece for pH of these taxa.

The dtsof the CCA an that the Physidae taxa are mipondhg significantly to the environmental wiables @ = 0.0û5) with 23.6% of the species pmeace accounted for (Figun 2-17). The plot shows A. elongata to be comlated to bclow average dissolved oxygen and pH. Howeva, the small sample sk(n = 3) wouM have prohibitai developmcnt of a strong unimodal response to a particular variable so this correspondence may not k relevant to the ecuiogy of this taxa.

Clarke (198 1) gives the distribution of A. elongata as tbrwgbout llORhem BC. 'Ibis study did not fuid such a widespeed dimion but Bmh (1989) d&be the distribution to include AhrLa and Washington putes which iniplies the Mbution may includc wich of the stdy am. This potentiaiiy widespcad distribution givcs no indication of any bunas arountaed during pst-giacial dispersion.

Cluke (198 1) dcscribes of A. elongata a occurrbg pMcipaUy in vernal habitats. The ecologicai sites in stuây wae mcyed pimarily during Au- whcn many vdhabitats may not have becn conspicuous anà, dwing this time, A. elonguru w coliected only hmpamn*l-type habitats (laices and ponds). The ~oîiectionsde at the nmlccologid sites wcn deaulier in the Saron and wae made hmvd habitats (marsha and floodcd areas).

*Note: Refdto as Rplahpmmrn by Cluke (19734 1981). A. @nomm is now rrcogaized as king a distinct Einas*n species (Burch 1989). Physa jennessi* Dall, 1919 Obîuse physa

ECOPROVINCEIECOREGION Northern Bord Mountains: Barcal Mountains and Plategus BiûGEOCtIMATIC (BGC) ZONE Boreal Wbite and Black Spnice

Figure A47 - Collection sites for Physa jennessi,

Pmiousiy recorded distribution in northern BC: Not previously recorded (Clarke 198 1). Discussion: Physa jennessi fiom northem BC is repfcsc~ltadby one collection held at the Canadian Mn of Nature. Clarke (198 1) reports the distribuîion of P. jennd jennesi (sec *Note klow) as the Arctic region of Canada aithough he made this collection at Dcsre Lake in 1972. Burch (1989) give the disüibution of P. jemessi as Alaska, Northwest TaTitories and BC. Firrther swy work is rspuirrd to merdefine the actual distribution of this specie in BC.

*Note: Rcfcned to as Phym jennessi jemessi by Clarke (1973b, 198 1) and as Physa jennessi by Burch (1989) and by Turge~net al. (1998). Physa skinneri* Taylor, 1954 Glass physa

PACmC: Yukon: Ath( t ) ARCTIC: Liard: Dease (2), Liard (1); Pace: Kiskatinaw (l), Pine (l), Smoky (1) ECOPROVINCE/ECOREGION Bord Plrins: soutban Alkria upw(3) Nortbem Bord Mountrins: Liard Basin (l), Bortal Mountains and Platcaus (3) BIOGEOCLCMATIC @CC) ZONE BodWhite and Black Spnice (7)

b Figure A-18 - Collection sites for Physa skinneri. Enviionmentai Information:

Tempcrtl~("c) 4 15.70 1.O4 13.80 18.50 Dissolved @ (% Saturation) 4 69.75 9.83 45 .O0 87.00 Conductivity (psiaams) 4 327.25 78.76 193.00 550.00 Calcium (mmtrc) 4 47.46. 1 1.74 27.44 80.67 [PH 1 41 7.991 0.121 7.701 8.301 htviou~lyrre~tdd distribution hi northern BC: Recordcd hmfat astern am(Clarke 198 1). Discussion: Physa sAinneri is an uncommon molluse in northan BC being found at smo of 176 sites. It was found in bah the Pacific and Atlantic drainages and in the bonal-type ecopmvinces. The BGC zone in which it was foui has a mean annual tanpcnihirr of -2.9 to 2.0.C with up to 7 mnths below O"C and up to 4 months lbow lOOC witb annuai prccipitation mging hm330 to 570 mm.

The range and maiis of the enviro~~entalvariables for the sites whac P. srkinneri was coîiected are showninFigurr2-11.

Tniipaahlp: Figure 2-lla shows that Physa skMen was collecteci oniy in habitats of nlatively low temperature. Howeva, Taylor (1988) indicates that P. skinneri ocnirs thmgbout westem North Amenca, as far south as Colorado, and so it seems unliltely that temperature would k a limiting factor in the distribution of tliis species. Dissolved Oxv~en:Figure 2-1 1b shows that P. skinneri was not found in habitats whm the dissolved oxygen was as low as it was for most otha physids in this study. However, as physids geaerally nraintain a dependence on atmospheric air, it is not expected that their distributions may be limited by the amount of dissolved oxygen in a habitat.

Conductivit~and Calcium Concentration: Figure 2-1 lc shows that P. skinnen' was only found in habitats of relatively high conductivity/calcium concentration with a minimum of about 27.4 mg calciurdl recorded. Aithough the saaiple size is small (n=4) and may not aîiow representation its fbli range of tolerance, it may be that P. skinnen is a calciphüic &astropod, restxicted to habitats with high levels of calcium as defmed by Russell-Hunta (1 978).

& Figure 2-1 Id shows that P. skinneri is one of the few gastropods in this study to be collected only in alkaline conditions. The mean pH of P. skfnneri is sipificantly higher than that for A. elongatu (p4.015) and the ranges of the two species do not overlap. This suggests that these two species may be separated ecologically by the pH of a habitat. Howeva, the sample sizes for both of these species is smeli (n = 3 and n = 4) and these values may not accurately represent their tme ranges of tolerance ta pH.

The resuits of the CCA are that the Physidae taxa are rcsponding sipificantly to the environmental variables @ = 0.005) with 23.6% of the species presence accountd for Figure 2-17). The CCA plot of the enviro~ientalvariables shows P. skinneri not to k codated with any particular envirocunentai variable, which may k due to its small sample sue.

CM(198 1) indicates tbat P. skinneri occurs in northm BC ody in the far castan am. This study found a more widespnod distribution, with P. skimen' also behg collacd hmthe northwcst of the study area. Taylor (1988) deoaibes the distribution of P. skinneri as Alaslo southeast to Ontario and Michi- south in the western United States to castan Washington, Nevaâa, southan Colorsdo, and noahan Nebraska, and Burch (1989) describes the distribution as Canada bmQucbec to Bc; wuth to Washington, Montana, Wyoming, Nebraska, Iowa, Ohio, Pumsylvania and New England. Thus, the distribution of P. skinnen sams to k much Mertbm that recognized by Clarke (1981), which conciin with the findings of this study. As P. sùiruaeri is aIso hown hmthe USSR (Taylor 1988), it may be thrt P. skinnen*movd hoBC âom both the Mississippi and Baing refugia. In this study, and in those citai above, P. skinneri does not apprto k associateci with the Pacifk coastCOSISt

Clarke (1981) dcscri'bes the habitat of P. skjnneri as lakes, ponds, des,and slow-mving streams, and Taylor (1988) as ponds and msffhes or smaü setpms neer such situations. WeP. skjnneri was never fodin a sea~during this sndy, it was found in lakes, ponds aud des.

*Note: Rtfdto as PIryso jennessi skinneri by Clarke (1973b. 198 1) and as PPhy skànneri by Taylor (1988), Bmh (1989) and Tqcon et al. (1998). SITES (69): NlOOO,NlOOlJJlOO2,N1003,N1004, PhyselIa spp. N1005,NlOl l,N1014,N1015,N1016,N1017,N1019, N1020,N102 l,N1026,N1030,Nl033,N1036,N1037, N1040,N1043,N1046,N1048~1049JJ1052,N1054, N1055,N1057,N1058,N1059,N1060,N1070,N108 1, NlO84,N109 1,N1092,N1093,N1097,N1098,N1100, Nt 101,Nl102,N1103,N1104,N1105,N1106,N1107, N11lO,Nl111,Nl112,NO100,NOl05,N0107,NO110, NO1 12,N0113,N0114,N011S,N0116,N0120,N0125, N0132,N0133,CN101l,CNlO15~1004,MNlûû5, MNlOO8,MNlO 10 DRAINAGEJWATERSHED PACIFIC: Fliscr: Fraser (8),Nechako (12),Sniart (4); Ni#: Nass (1); Skccnr: Babine( 1). Bullclcy(3), Wtse( l),Skeeaa( 1); Stkine: Stikin~(1) A~CTIC:Liard: DaK (3)jon Nelson (8),LLUrd (7). Toad (1); Perce: Btacton(3)~~w(2),Peace(12),

ECOPROViNCE/ECOREGION BadPlains: Pcace River Basin (2), Central Albcria UplanAn (3). Southcm Aiberta UpW(3) Centrrl Interior: Fraser Pb(1 1) spp Figure A49- Collection sites for Physella Coast & Mauntrias: Casai Gap(l),Nass Basin(l), BIOCEOCLIMATIC ('cc)ZONE Nakges (1) BodWhite and Black Spruce (30) Norlhern Bord Mountrin~:Bortal Momtains & Piatcaus ( 1 ), Northern Canadia ROC@ Mountains (1). cmtal watan HcmloCk(1) Liard Basin (10) Engelmann Spruce - Subalpine Fir (1) S~b.BorcilInterkr: Fraser Basin (24). Centml interior Crdir - Hwlock (2) rarudian RocIEy Moutains (3) Sub-Boreai Spmce (35) TdpP~s: Hay River Lowland (2), Nortbcm Albcria UpW(2), Hay Riva Lowland (4)

Tempera Co 50 19-41.. 0.50 12.10 26.50 Dissolved 4(% Saniration) 50 70.33 3.58 7.00 135.00 Conductivity (psimens) 50. 304.15 39.36 76.90 1568.00 Caicium (mgtlitre) 50 44.0 1 5.87 10.13 323 -45 pH 50 7.47 O. 10 5.60 9.25

Discussion: The Physella spp. group bss not ken idded to species in this shidy as the anatomid expdsc ncceswy to do so was aot avaîiable. Thcse physiâs arc very connnon moîiuscs of no- BC being fodat 69 of 176 sites. They wat found in both the Pacifie and Arctic drainages in ail of the noahem dcop~ovinces.They wac found in ail but the Spnice-Wi11ow-Birch BKzone, wbich was one of the lavit reprc~eatedBGC zones in tbis study.

The mge admeans of the cnvirommtai variables mcaaord at the sites whae Physeila spp. FdyPbysidac Physelb m.

Taamrature: Figure 2-1 la shows that the Plrysellu spp. group was found at tempemtures >2S°C suggesting that high teniperature rnay not be a lunithg factor in the distribution of this taxa.

Dissolved Oxyg- Figure 2-1 1b shows that Physella spp. were found over a wide range of dissolved oxygen. However, as physids genefally maintain a dependence on atmospheric air, it is not expecteâ that their distributions rnay be iimitd by the amount of dissolved oxygen in a habitat.

Conductivity and Caicium Concentration: Although Physella spp. wae common throughout the study am, Figure 2-1 lc shows that they were not collected hmthe habitats of lowa conductivity measured in this stuày. This suggests tbat these physids may have a minimum calcium requirement that may restrict them to certain habitats withia th& range.

Figure 2-1 Id shows tbat Physella spp. wen collected ova a wide range of pH, in both acidic and aWeconditions. This suggests that pH may not be a limiting factor for this taxon, howeva, the tolerances of the opecies that may k containeci witbia this gmup is pmtlyunknown.

The resuits of the CCA are tbat the Physidae taxa are responding significantly to the environmental variables @ = 0.005) with 23.6% of the species pnsare accounted for (Figure 2-1 7). The CCA plot of the environmental variables shows Physella spp. to occw at the mean of all the meastues and not to correlate to any particuiar variable.

Tbc Canadian Museum of Nature bas appmximately 79 lots of unidentifid physids from BC in the accdcoilactions and approximately 45 lots in the backlog of non~essedcollections. At least five of these lots arc hown to k ûom norihan BC. Meanwhile, while Clarke (198 1) indiata that Physella &yn*~should be a commwi species throughout northern BC, thae are no vouchcr specimens to substantiate this sistement. This study found Physella spp. thugbut northem BC but fllrther identification is necassry to àelimit the distriiutions of the species within this mup.

Physella specics en known hmelmost aü paennial and temporary habitats (Cbrke 1981, Burch 1989). wbich concurs with the wide habitat range fouad for the Physella opp. grntp in this Jnidy. FImily Physidac I Physella lordi Physella lwdi (Baird, 1863) Twisted physa

SITES (2): CN1012, MN1001 DRAINAGEMATERSHED ARCTIC: Pt8ct: Peace ( i), Pine (1)

Bord Plab: SouthAlberta Uplands (1) SubhnilInterior: FmBpPio (1) BloCEoCLIMATrc (BGC)ZONE Bord White and Black Spnice (1) Sub-Bord Spniee (1)

Figure A-20 - Colleaion sites for Physella lordi. Reviously recordcd cüstributioa hi northern BC: Pace Riva system (Clarke 198 1). Discussion: Physella lonii hmnorthm BC is rcpmentd by two coiIections held at the Cadian Museum of Nature. The Physella spacies collected during this study have not ban iddedto spccics and this group of coliections niay include additional records for Physeila lordi. Ciarkt (1981) states thst P. lordi is found hmriorthan BC (Pae River systan) south to the western Unital States. Physella propinqua (Tryon, 1865) Rocky Mountain physa

SITES (2): CN1017, CN1021

DRAINAGEAVATERSHED

Cola* & Mountains: Nass Ranges (1) Sub-Bored Interior: Fraser Basin (1)

BIOCEOCLIMATIC (BGC)ZONE interior CdHemlock (1) Sub-Boreal Spruce (1)

Figure A-2 1 - Collection sites for Physella propitupu. Previoudy neorded distribution h northern BC: Central BC (Clarke 198 1). Disco~ion: Physellu prupimpa hm northem BC is repmmted by two collections held at the Canadian Mwum of Nature. The Physellu species oollcctcd durhg this shidy have not ken identified to species and this grop of collectio~~~may iuclude additional ncoids for Physella pmpinqu

Physella virginea * (Gould, 1847) Sunset physa

SITES (1): Nl lO9/CN1023/MN1012 DRAINAGWWATERSHED ARCTIC: Llrrd: Liard ECOPROVINCEECOREGION Northem Borcil Mountains: Hyand HiPhlanA BIOCEOCLIMATIC (Ba)UlNE Bord White anci Black Spruce Figure A022 - Collection site for Phpella vitgineu. @M. Previourly neordeci àistribution h northern BC: Not previously ncorâai. Discussion: Ciarke (1981) states that Physolla vi@nea is tentativcly considacd a synonym of P. lordi. and Taylor (1981) incldes P. vi- in a list of synonyms of P. Howmr, Burch (1989) and Turgeon et al. (1998) rccognize P. vi@ll~aas a distinct specics.

PhyseIla virgfnea hm northm BC is rqmmtad by one dation heid at th Candian Museum of Naîm. The Physella specia collectai dur@ this sRidy have pot ken ickntified to specics and this pupof collections may inclde additional records for Physella virginw. Bmh (1989) üst the distribution of this spacics as BC south to California.

*NO&: Spccimcns at the CMN am îabded "type pchms" but it seems unlilttly thaî the specimens âcscrikd by Gouid in 1847 wac coUcetsd hmtbis location, Physella wrfghti Te and Clarke, 1985 Hoîwater physa

DRAINAGEIWATERSBED ARCTIC: Liard: Liard

Northwn Bord Mountains: Hyland 1 Hi- BIocEocLIMATIc (BGC) ZONE Boreal White and Black Spmce

Figure A-23 - Collection site for Plpella wnglti. Environmentri Information:

Reviousîy recorded distribution h northern BC: Liarâ Riva Hotsprings Provincial Park (Te ad Clarke 1985). Discurrion: Physella wnghti was found at one site during Usstudy. This is its type ldty,a 34-m reach of Alpha Stream, which emagcs hmAlpb Pool in Liard Riva Hotsprings Provincial Park The climatic and aivironmental conditions are very diffamt a tbis site thm dsewhere in.northanBC.

nmcntal Variables: The enwOnmcntatnmcntatvariablcsfor the one site for P. wnghn' arc presenîed in Figure 2-1 1. This unique habitat bas the hi@ tcmpw~crccordod in this sbdy (36.E) and the lh9d highest conductivity (1155 CS). The temperature anâ conductivity for P. wnghti were found to be significamly higher than for any of the okphysids in this stuây for which these meamemcnts are available flable 2-7). This refîects the vay Mihabitat of P. wnghn' as compad to othcr physiL in this shdy. The dissolvecl oxygcn snd pH at which P. wghi was found wac within the range of most of the othcr physids species. The results of the CCA are that the Physidae taxa are respondiag significantly to the environmental variables @ = 0.005) with 23.6% of the species pnsence accounted for (Figure 2-17). While thae is an insufficient sample size of P. wnghti for the CCA anelysis of the environmentai variables to show a uaimodal rrsponse, this spics does appear on the plot associated with vqhigh measures of temperature and conductivity which is in accordance with its ecology.

P. wnghti is believeà to be a relict species, having survived glaciation at its type ldity. Rest (1976) suita that stratigrapbic evidence indicates that the Cordilleran and Keewatin ice sheets made contact in only a few places in the Liard Plateau and adjacent plains leaving the intdunglaciated. It is within this uaglaciated area that Liaid River HotspnPgs is located. Te and Clarke (1985) believe that P. mghti may bave survivecl at its presex~tlocality for at least 100,000 years. A full review of the known habitat parameter and bioloogy of P. mghti is presented in Lee and Ackerman (1999b). Based on this report, this spsies bas now been listed as "Endangered" by the Cornmittee on the Status of Endangerd Wildlife in Cana& (1 998). Gyraulus circumstriutus (Tryon, 1866) Dise gyro . . SITES (70): NloOO,NlOO l,NlOOZ,NlOO3, N1004,NiOO6~1007~1008,N1009J1010~1012, N1014,N1023,NlO26,N1027,N1030,N103l,NlO33, Nl035,N1036,N1037,Nl039,N1040,N104l,NlM3, N1046,N1048,N1050,N105l,N1052,N1053,N1054, . . N1055,N1056,N1057,N1058,N10S9,Nl060~1061, N1062,N1063,N1068,N1069,N1070,N1072,N1073, NlOï4,N lO77,NlO78,NlO8 l,N1082,N1084,Nf089, N1û90,N109i,N1092,N1093,N1098,N1101,N1102, N1103,N1104~1105~11091CN1023,N1110, NO1 13,N0121,N0126,CN1014,MN1000

: DRAMAGE/WATERSHED -ER: CoarEiI: North Cow (1); Fraser: Fraser (l), Nechako (4), Stuart (2); Nam: Mefiadin (1 ), Na(1);Sk~m: Bulkley (4), Lakclsc (1). Skeena (4); Sa)rjnt: Srikiae (5) Yukon: Ath( 1) Lhrd: Deaac(7), Ft NeIson(8), LM(10)IT08d(l); M&tmk: Hay (2) Figure A-24 - Collection sites for G~IIUI~LT Ptace: Halfway (l), Kiskatinaw (2), Pdp circumshh~. (1)S- (1 11, Pb(2)

Bord Piah: Cenaal Alberta UpW(2), BIOGEOCLIMATIC (BGC)ZONE Puce River Bash(2), Southem AlhUpW (5) BodWhite and Black Spnicc (43) Cenarl Interior: Fraser Plataua (7) Coastal Westem Hemiock (2) Corrrt & Mo& Norhcm Coa~talMu.( 1), Engelmano Spruce - Subaipine FU (1) coaatai Gap (l), NeBasin (3), Nas Ranges (3) Interior Ccdar - Hdwk (6) Nortbem Bord Morintrlar. Northan SubbdSpnict (18) CPaadUn Rocky Mountrins (1). Liard Baain (14), Hyirrd Highbd (1), Bord Mis. and Pkteaus (8) SubBoral Interior: CdCaMdian Roclcy Mta. (2), Omhaa Mo~~~tpinr(2). Fraser Bmin (8) Tdg8 Piah Hay River LawIand (7),Noitbcm Alber@ UP~(3) Environmentai Informrtion: Memurement Copnt Mean Stà.Emr Minimum Maximum Tmiperature (OC) 65 19.16 0.5 1 1.50 26.50 Dissolval (% Saturation) 65. 66.20 2.80 . 8.00 99.00 CoQductivity (psiaiuiis) 65 297.12 27.27 47.40 1199.00 Calcium (mfitm) 65 42.97 4.07 5.73 177.44 pH 65 7.54 0.09 5.90 8.90

sites. It was fdin bOth the Princ and Arctic drainages, in aii of the major watersheds, ad in all of the ecopmvinces. Witbin the five BGC zones in which G. ~Umrntstrioiurwas collectai, mean mual temperatures range hm-2.9OC to 1O.S0C with up to 7 maths klow 0°C and up to 6 mouths above 10°C and with annual precipitation ranging hm330 to 4400 mm.

The ranges and means for the environmental variables meslsufed at the sites where G. circumrtn'4îu.s was collected are shown in Figure 2- 12.

Tem~etamFigure 2-12a shows that G. circuntptnatus was fouud at temperatures >25OC suggesting that high temperature may not be a limiting factor in the distribution of this taxa

Dissolved.Oxvm Figure 2-12b shows that G. cir~1mrtnatu.swas collected from habitats of veq low oxygen saturation. This suggcsts that G. circumniatirs may be an oxygen-independent spc~iesand tbat the dissolved oxygen saturation of a habitat may not be a Limiting factor in its distribution in aorthem BC. . . Conductivltv and Calcium Concentratiao: Figure 2-12c shows that G. circumshhah*r,while coilected from habitats of relatively low conductivity/calcim, was not collected at the sites of lowest conductivity in this study. Given the large sample sue for this species, it may be that'G. circumstnatrrr requires a minimum of40m@ calcium to successfdly colonize a habitat.

a Figure 242d shows that while G. circumptn'atrcr displays a wide range of tolenr~ceto pH, and was found in both acidic anci alkaline mditions. it was not fdat as low pH as wac some otha planorbi& in this study. As G. cimmstnattcr was a vay cornmon specics at ccoiogical sita (n=65), the fïnâjngs bac may k a good indication of its tolcrance and it may not k able to tolarte pH levels lown hnthe minimum of 5.9 at which it was fod This may be linLexi to its putative minimum requllcmait for calcium as discusscd above.

The teSuIts of the CCA arc that the Pbrbidae are rcspocdllig sipificantly to the environmental miables @ = 0.005) with 8.8% of the spacies pcsare rccounted for (Fi- 2-18). The plot shows G. circunshiatirr to co~csporsdmost closely with slightly higher than average conùuctivity. Given the wide muge of cobductivity/calcium ovcr which G. circumrilicrtrrs was four& it does have a somcwhat higltcr mean for tbis variable than do many olhcr planorbi&. However, coaductiviitycalcium does not appear to be a particuiarly important ecologicaî hrfor G. circumhiatw and its placement on the plot is close to the ongin may k of lunitcd ecological înterprctabiîity.

Clarke (198 1) indicaîs that G. cimmtrirrtirr is founâ in afl but the far northwest of northem BC. This study cailected G. circlunrtriotrrs hmtbn,u@ut the shdy mi adfod a ncord for this species in tbe Éir oorthwest (lbfIU1ûûû) indicating that the rnnge of G. cimmstriatrcs is througimut aii of northcm BC.

Clarke (198 1) statcs that G. curwnthiotirr is characteristic of d.vanal habitats. in this study it was fodin ail typcs of habitats, both mail and Jargc, and both pacmiial anci vernai. Clarke (1981) incluûes another Gyroulus spccies, G. vennicuIaris, as occming in northem BC in pmnnial habitats. His description of this species was not succinct enough to distinguish it hmother Gyrautru species and G. vemicvlaris is mot recogawd by Burdi (1989) or by Turgeon et al. (1998). Therefore, the more diverse habitat type fond for G. circunutnàîus in ihis sndy may be the resuit of G. verniadaris kiog included with G. circumtnohrs when specimcas hmthis study were identified. Gyraulus crista * (Linnaeus, 1758) Star gyro I

DRAXNAGElWATERSEED PACIFIC; Firicr: Nechako (1), Sm(1) ARCTIC: Liard: Lùrd ( 1), Pace: Pace (1)

Bad Plains: Peact River Basm (1) Centrd Interior: Fraser Pb(1) Northtrn Bord Moiintrias: Liard Basin (1) Sub-Bond Interior: Fraser Basin (1) BIûGEûCLIMATIC @CC) ZONE Boteal White and Black Spruce (2) SubBod Sprue (2)

< Figure A-25 - Collection sites for Gytarclw CM. Environmentai Informrtion: ,Memurement Couat Man Std.Emr Minimum Maximum Temperanire (Oc) 4 19.60 2.6 1 12.20, 24.00

Dissolveci 02 (% Saturation) 4 - 48.25 17.30,. 19.00 93.00

Conductivity (psiemcns) 4 477.18 247.45 ' 119.70 i 199.0 Calcium (rnfltre) 4 69.8 1 36.90 16.5 1 177.44 pH 4 7.56 0.27 6.85 8.15 RevlousJy recorded dhtribution hi norOern BC: Not previously mrded (Cm1981). Discussion: Gymlhrs chta wuan imeommoa moUusc in northcxn BC king foui at four of 176 sites. h was fouad in both th Pocific and Arctic drainages ad in fow of the six nonhan ecopfovinces. The two BGC zones in which is was fond hrve mcrn annuai taqaatum mghg hm-2.9 to S.0.C with up to 7 months kiow 0.C and up to 5 mohabove 1O.C anci with muai pmipitation ranghg hm330 to 990 mm.

The ranges and means for the environmental VariObles mdat the sites where G. cristu was collected are shown in Figue 2-12.

Tcaioaaturr: Figure 242a shows thst G. &ta was fodat rclatively high tanpaanaar suggesting that temperature niay not be a limiting motfor the distribution of this species in northan BC. Dissolved Oxvncn: Figure 2-12b shows that G. tata was collectexi hm habitats of low oxygai saturaiion. This suggests that G. cristu may be an oxygm-independent mies and that the dissoived oxygen saniration of a habitat may not be a limiting factor in its distribution in northern BC.

Conductivitv anci Calcium con cent ratio^ Figure 2-12c shows that G. c*tu was not found in habitats of as low cond~~tivityl~alciumas were many other planorbi& in this study (minimum 16.5 m@i). However, the small sample size (n=4) for this species may not give tnie representation of the minimum calcium requirement for this species.

Fip2-12d shows that G. cristu was found at a relatively testncted range of pH as compared to otha species of planorbids and was usually coiiected hmaikaline conditions. The pH, king related to the calcium concentration of a habitat, may be a f-or restrieting the distribution of G. crista. However, the sd-le size (n=4) many not give an accunite represaitation of the entire range tolaable by this

The results of the CCA arc that the Plrnotbidat are responding si&dy to the environmentai variables @ = 0.005) with 8.8% of the species pmence accountcd for (Figure 2- 18). The plat shows G. cristu to eomspond most closely with higha tban average conductivity. Figure 2-12c shows thai G. crista has the highest mean conductivity of rny taxa in this fdybut it is probably the minimum calcium repuirement thnt is important to most taxa anâ the smaiî simple sue for G. crista (n4) limits the interpretab'i of placement on the plot.

Clarke (1981) does not include northan BC within the range of this spacies although his inclusion of a site in the NMiT indicatcs that the range is pbably man widapread than wm hwnat tht time. In tbis study, G. cristu was coliectd hmsites scattercd tbrwgbut the stuày am including sites ast of the Rocky Mountains in BC and in the Pacific drainage, grealy inCrtashg the isordtd distribution for thh spccies.

Clula (1981) stats that this pcies lives among deaK vegctation-ineutrophic ponds anci slow moving streams. In tbis dy,G. crista, which is vny d,was only found in carcfiil ambation of the bottom of mch or submagsd wdmà wuneva colkftd hmsweepings of vegetation Thus, the habitat range sppears to be more diverse than thrit inâicated by Clarke. Gyraulus defectus (Say, 1824) Flexed gyro SITES (33): NlOOl,N1ûû4,N1005,N1006,NlO14~1015,N1026, N1032,N1033,N1034,N1037,N1038,N1042,N1056, NlO92,NlO93,NlO96,IU1097,N1098,N1100,NI101, N1104,N1106,N1107,Nll1O,N1112,NO104,NO114, NO1 lS,NOlL6,N0122 MN1008.MN1011

PACIFIÇ; Fraser: Fm(3). NCC~(7). Stuart (3); Skeenr: Babine (2), BuWcy (3) mmC: Liard: Dcuc (1). Fort Nehn (S), Liard (1); Mickedt: Hay (1); Pace: Kiskatinaw (1 ), p=c (6)

Born1 Plrins: Central Alberta UpW( 1 ), Soutbern AlhUplanAp (2) Central Inttriorz Fraser Plateau (8) Northern BodMomtrins: BodMountains and Piamus (l), Liard Basin (1) Figure A-26 - Collection sites for G'uulhrr deflec~ SubBod Interior: Cmtral Canadian ROC^ Mountains (l), Omincca Mountains (1) BIOGEOCLIMATIC @cc) UlNE Sub-Bodinterior :Frastr Basin (12) BodWhia and BWSpniee (12) Tdgâ PmNorrhnn AlbUplrPds Il), Hay Sub-Bod Spe(21) Rivcr Lowianâ (5)

Environmental Information: J

Temperaiure (OC) 26,. 20.25 0.77 12.20 27.20 Dissolved 01 (% Saturation) 26 70.3 1 4.00 23.00 98.0 Conductivity (psianau) 26 2 16.80 42.44 76.90 1 199.00 Calcium (mfltre) 26 27.73 5.70 8.92 159.73 9H 26 7.34- O. 15 5.60 8.75 Previously recordcd distribution in northern BC: T'u~utmRhm BC (Ch& 19%1). Diacuuion: GymIw dewcnu was a comnmoUusc in no- BC king found at 33 of 176 sites. It was founà in ôoth the Pdcand Arctic drainages and in di of the natkm ecaprovinccs. It ocdin only two BGC zones, thoe u>ms king those containhg most of the sites in this shdy. Thcsc two BGC zones have mean muai tcmpaahnes mghg fiom -2.9 to 5.VC with up to 7 months below VC and up to 5 months above 10°C and with annuai precipitation nurging âom 330 to 990 nma.

The range d mesn for the envitanmentai variables wssimd at the sites whae G. dejlccnu was collectai are shown in Figure 2- 12. Temperature: Figure 2-12a shows that G. dejrecm was collected at temperatures >25T suggesiuig that temperature may not be a limiting hctor for the distn'bution of this species in northern BC.

DisJolvod Oxvncn: Figure 2-12b shows tbat G. dellechu was collectai fiom habitais of relatively iow levels of oxygen sahinition. This suggests that G. dejlecncs may be an oxygen-inâependcnt spccies that îhc dissolvd oxygen saturation of a habitat rnay not be a limiting factor in its distniution in northm BC.

Conductivity and Calcium: Figure 2-12c shows that G. dejrech*~,whiie coilected hm habitats of relatively low conductivity/calciium. was not collated at the sites of lowest conductivity in this study. Givcn the relatively large sample size for this species, it may be tbat G. dejecm requins a minimum of -10.0 mg/l caicium to successfully colonize a habitat.

& Figure 2-12d shows that G. dej?ecm displays a wide range of tolerance to pH king found in both acid and allraline conditions. This suggests tbat pH may not be a limiting factor in the distribution of this species within northern BC.

The mults of the CCA arc that the Plauohidae am mponding signifiuntly to the envVonmentd variables @ = 0.005) with 8.8% of tbc spccics pr*wce accoimtcd for (Figure 2-18). The plot shows G. deflectirr to correspond to slightly lowa tban average values of pH. Figure 242d does not indicate that pH is a sipdicsnt variable for this spaics and its placement on the plot, so near the origin yct siightly off& to pH, may be of Limitai ecologid consequence.

Clarke (198 1) Uidicatcs th dibnion mgc of G. akjleccirr ta include alî of mrthem BC. Tbis connin with the findings of this study whnin G. deflectrrs was found to bave a widespd distriiutio~~. Tbis widespnsd distribution gives m evidcaK of any barrias imposcd duniig pst-giacial ldispasioe

ClrrLe (1981) states tbit G. defiecm occun in aU LiaQ of permencnt-water, eutrophic haôitats. In this My,G. de/lcch~was coiidhm tbose types of habitats king fodin the vegetatd portions of îakm, ponds, swamps and the slow moving uac of stmms. Gyruufusparuus (Say, 181 7) Ash gyro

DPAGWATERSHED PACIFIC; Fraser: Fraser (9,Nechko (2), Stuart (3); NI#: Bell-Inhg (1); SIrcc~:Babine (1); StiIdat: Stikine (2); Yukon: Atlin (1) ARCTIC: Liard: Dciue (3), oit Nchn (2). Lhd (3); Pt8ct: Pannip (l), Peace (3). Pine (3) ECOPROVINCE/ECOREGION BO^ WS:Pcaet River Basin (1 ), Southmi Alberta Upianàs (2) Northern Bard Mountrinr: Noitbern Carnadian Rocky Mountains (l), Bord Mountains aad PIatcaus (3), Liard Basin (6) Fi- A-27 - Collection sites for Gyrmtlw par~. Sub.Boml Interior: SLcena Mountains (1), Centrai BIOCEOCLIMATIC (BGC) UlNE Candiui Rocky Mountains (4), Fraser Banin (9) Bord White anà Black Spruce (14) Tdip Phim: &y River Lowland (1) EngehSprucc - Subalpine Fu(2) Inthor Csdar - Huniock (1) Spruce - Willow - Birch (1) Sub-Bonal Spnrc ( 10)

Reviou~~lyrecordcd dirtribptlon h northern BC: hughout northun BC (Clarke 198 1). Di8 cris sion: Gyr~uIt(sparvirr was a cornmon mollusc in dcmBC king foimd at 28 of 176 sites. It was found in both the Pacifie and Mcdrainages anâ in four of the six ecoprovinccs. The four BGC zones in which it was coiicctd have mmannual tempaha*i ranging hm-3.0 to 8.X with up to 7 m~nths bclow ODC anâ up to 5 month above l(PC adwith mual precipitation mging hm330 to 2200 nm~

The range and mean for the envinmmemsl variables messund at the sites wbae G. pm~uwas coH.ectd ate sho'ikn in Figure 2-12. Terg~ets- Figure 2-12a shows that G. paw was found at temperatures >25OC suggesting that high temperature may not be a Mting factor in the distribution of this taxa.

Dissolval Oxvm Figure 242b shows that the minimum oxygen saturation at which G. p4m was collected is higher than for many of the other planorbids in tbis study, and bigha thPn for any 0th- Gytoulur species. This may incücate that G. pow, uniilce the other Gyraulus species, is oxygendependent. This hypoxia imolerance rnay be a limiting faor in the distribution of G. pamin northem BC. . . Condumwtv and Calcium: Figure 2-12c shows that G. pum was collected down to a minimum of 12.0 m@ calcium concentration. It may be that G. punw requins this minimum level in order to successfully occupy a habitat and tbat this rnay limit its distribution in northern BC. pJ& Figure 2-12d shows that G. purvus displays a wide range of tolerance to pH king found in both acid and alkiline conditions. This suggests that pH may not be limiting factor in distribution of this species within northem BC.

The dtsof the CCA are that the Plmrbidae are hsponding signincantly to the environmental variables @ = 0.005) with 8.8% of the spacies piacece 8ccounted for (Figure 2-18). The plot shows G. p4m to correspond to lown than average tempera~eand higher than average pH. The above information cxtrapolated from the range plots &es pot indiate that eikof these mors is of partic& ecologid importance to this spccia.

Clarke (1981) indicatcs that G. ppm is fomd throughout northem BC. This is in sccodance with the tindings of this study whae G. pam was found thmugùout the stuày ana This widespesd distribution giws no cvidcnce of any barriers imposai âuring postglacial dispasion.

Clarke (1981) states that G. po~uliva m d Linds of pcrmanent or tenipomy wata-Ued habitats tht support vegctation. This is consistent with the nndiogs of this sady whm G. pmvvr was fouid in mmy diffèrent types of vqctatai habitats. Gyraulus vermicularis (Gould, 1847) Pacific coast gyraulus* SITES (10): CN1000,CN1001,CN1004,CN1005,CN1008,CNl 009,CN1010,CN1024~100S~1007 DRAINAGE/WATERSrnD PAC(FIC: Fnwr: Nccbako (I), Stusn (2); Stikine: Iskut (1) ARC'MC: LM:Kechika (2), De= (3); Pcree: F~Y(1) ECOPROVINCE/ECOREGION Centrai interior: FmPlateau (1) Nortbcrn Borai MouneNorthern C& Rocky Mountains (l), Borcal MU.and Plateaus (6) SubBord Interior: Fraser Basin (l), ûmineca Mountains (1) BIûGEûCLIMATIC (BCC) ZûNE Boreai Wbite anci Black Spwe(5) Collection Spruce - Wdow - Bkh(2) Figure A-28 - sites for Gyraulw Sub-Bord Spnice (3) vennicirlaris.

Previously recordcd distribution hi northern BC: ùi Pacific drainage (Clarke 198 1). DiScusdon: Gyraulw vemiculuris was not otphdas king a distinct specics for tbis snidy. Clarke's (1981) description of thip spccies was not succinct enough to distinguish it hm0th G'auIw spccies and G. venni*culari

CWc(1981) alSb charactcrized G. vembcuiarisas king fouad only in the Pacific drsinage but the dtsof his own collections show that hc collectai G. vemicularis hmboth the Pacific and Arctic drainages. This fiutha puis in to question the validity of G. vennicularis as a distinct species rrstricted to the Pacific Coast.

*Note: The common namt coma hmClarke (198 1). 1

Menetus opercularis * (Gould ,184 7) Button sprite

DRAINAGEIWATERSBED PACIFIC; Coi~td:Nortb Coast (1); Friser: Nechako (21, Stuart (1); bs: Meziadin (1), Nass(1) S~M:Babint( l),Bulkley(l),Lakclst( l),Skna(1) ECOPROVINCE/ECOREGION Central Interior: Fraser Plateau (3) Coast & Mountains: Nass Ranges (1), Coastal Gap (2), Nass Basin (2) SubhdInterfor: Ftastr Bash (2) BIûGEOCLlMATIC (BGC) U)NE Coastal Western Hemlock (3) interior Cedar - Hemlock (2) Sub-Bod Spruce (5) Figure A-29 - Collection sites for Menem operctr1ari.s. Environmentai Information: ,Meumment Comt Mern Stâ.Error Minimum Muimum

TemperanUe w) 10 ~ 19.42 0.66 16.70 22.90 ,Dissolval 02 (% Saturation) 10 80.70 4.88 44.00,. 93.00 Conductivity (usiemens) 1O 103.28 15.20 20.10 163.40

htviously neorded dictribution in northern E:bwn only hmPacinc coast (Clarke 198 1). Dircuasion: Menetus opemluris was an rmwmmw moilusc in northcm BC being found at 10 of 176 sites. It was foui only in the Pdcdrainas in th ttDa southwestun ecoprovinces. The thrœ BGC zones in which it was found have mean mual temperatures nnging fbm 1.7 to iO.S°C with up to 5 month ôelow 0.C and up to 6 months above LOOC Md with mean annual precipitation ranghg hm440 to 4400 mm

The range and maris of the envitollllZCI1SB1 variabics at the sites where M. opercularis was coiicctcd arc shown in Figure 2-12.

T- T- Figwe 2-12a shows thit Y opetcirlaris was not dected at temperatures as bigh as were otha mcmkrs of this fâmily. In this mrdy, M. opercularis was only collccted hmlarge, permanent wata-habitats whnc die tanpartinr are oftai more stable than in smaller habitats. These data are mt sufficicnt evidence to suppose that M. opetcrrllmis is nstricted to these habitats due to intolerance of high tempersttm. Otha Eactors, such as kgh oxygcn rqhmcnt, may rcstrict it to stable habitats. Dissolved Figun 2-12b shows that M. operc11Iari.s was not coliected in habitats where the dissolveci oxygen was as low as for other species in this famiy. This suggests that M. opercularis may be oxygendepeudent. This hypoxia intoierance may be a factor that limits the distribution of M. opercularis in northem BC.

Conductivitv and Calcium: Figure 2-12c shows that M. opercuiaris was found at the lowest conductivity levels measured in this study. This suggests tbaî the level of calcium concentration in a habitat may not be a fktor limiting the distribution of M. opercularis in noithern BC. The limitai range of conductivity/calcium over which it was fond may be inherent to the paainial wata habitats that may be rquired to supply necessary oxygen. g& Figure 2-1 2d shows that M. opercularis was collectecl over a wide range of pH and in both acidic and basic conditions, down to the lowest pH measund in this study. This suggests that pH may mt be a limiting factor in the distribution of this species in northem BC.

The nsuhs of the CCA are that the Pianorbiche are respondiag significantiy to the environmental variables @ = 0.005) with 8.8% of the spccics prtsencc occounted for (Figure 2-18). The plot shows M. operailaris to cornlate to highcr than average dissblved oxygen aud lower tban average conductivity. This is in accotdance with the information daivd hmthe range plots in Figun 2-12, as discussed abave, and acts to verify tbat thesc cnvironmcnd variables msy be important fa- in the ecology of this species.

Ciarke (198 1) itldicates tbt M. opercuiculis is found in northern BC in aras vay near the m. In this study M. opercularis was foimd f&cr east than prwiously mrded but was still found only in the Pacifïc drainage. Ciarke (1981) ais0 records tbis spccies hmtwo locations in Alberta Md includes photographs of an Aldm specimen. and Burch (1989) records the distribution of M. opemlaris as AlasLi south to Alberta rad southan California Howeva, evidare hmthis stuày combinai with Clarke's (1981) idonnation, suggests thtM. opercufarisis probabty a milgant hmth Pacific refuge.

Ciarke (1981) states M. operculark is found among submased vegetation in paainial-water lakes, ponds and slow-rnoving portions of riven and strcams. In this study, M. opernJmlP was found in similar habitats.

*Note: Refdto by Clarke (198 1) as Meneius cm@. - Promenetus exocuous exacuous* (Say, 1821) Sharp sprite

I - - ...

SRES (37): Nlûû2~lûû4,NloO5~1006,Nl007, NlOO9,NlO lS,NlOZ l,Nl033JV1034~1043,Nlû46, N1053J1055,J1060,N1082,N109 l,NlO92,NlW3, N1096,N1097,N1100,N1102,N1103,N1104,N11C5, NI lO7,Nlll2,NOlO3,NOlO~,NOll3,NOllS,NOI16, NO12l,NO13O,CN1000,CNlOOl DRALNAGEIWATEMHED PACa(rC: Fraser: Fm(2). Nechako (6). Saian (6);Skeem: Sabine (2), BuWy (3), Skna(2) mat:Lhd: DaK( 1), Fort Nelso~3),Lisrd(2), Tord(l); Pau: B-n (1). Peace (7), Pinc (1) ECOPROVINCElECOREGION BadPl&#: Southem AlhUplandP (1), Peace River Basin (3) Ceatral Interior: Fraser Plateau (7) Figure A-30 - Collection sites for Romenetus exacuous Cm a M~~~-~:Narr Br

TanPenam ml 28 19.59 0.69 13.40 27.20 Dissolved 4 (% Saturation) 28 74.1 8 4.76 8.00 535.00 C~nductivitv(usicmens) 28 218.25 26.5 1 76.90 735.00

Disc~ssion: Promenetus e;itacuow exacuow was a eommon moiiusc in northcrn BC being found at 37 of 176 sites. It was found in both the Pacinc and Arctic drainages in ail of the pr pro vin ces. The thne BK zona in which it was foimd bave mean mual tcmperam ranghg hm-2.0 to 8.X with up to 7 montbs klow WC and up to 5 months above IOOC and with annuai pmipitation ranghg hm330 to 1200 mm.

The range and means of the ~vironmentalvariables mdat the sites whac P. exacuow exacuotLS was merisrmd are show in Figure 2-12. T-ture: Figure 242a shows that P. exacuous exacuous was found at temperatures >2S°C suggesting that high temperature may not k a limiting factor in the distribution of this taxa.

Dissolved OxvaFigure 242b shows tbat P. exaryous exafuow was found at the widest range of dissolved oxygai, and at the lowest levels measured for members of this family. This suggests P. exacuous exaaiora may be oxygen-indepcnâmt and that dissolved oxygen saturation of a habitat may not a limiting factor in its distribution.

Conductivity Figure 2- 12c shows that P. examow examous was found at a minimum level of calcium of 10.1 mgll. Tbis may indicate the minimum quireà level for P. exacuous examou to occupy a habitat, which may limit its distribution in northmi BC.

& Figure 2-12d shows that P. exacuouî exacuow was collated with habitats with a bmd range of pH, spanning both acidic and alkaline conditions. This suggests that the pH of a habitat may not be a limiting factor in the distribution of this species in northern BC.

The resuîts of the CCA are that the Planorbidae are responding signifïcdy to the environmental variables @ = 0.005) with 8.8% of the species presence accounted for (Figure 2-18). The plot shows that P. exocuofls exactcous accurs ncar the ongh of all of the environmental variables and so it Ur aot nspondiDg strongly to any single variable.

Clarke (1981) indicates that the distribution of P. exacuous exacuous includcs the fat east and northcast of northcrn BC. Bwch (1989) statts tbat this spies occuis in the US only east of the Roc$ Mountains. This stuày fomd P. exoorau exucuw widely distributcd throughout much of the study area, ad to be conunon west of the RocLy Moumin. This grcatly expattds th prcviously recordcd distribution for this @es.

Cluke (198 1) states that P. ~;~CICUOW~~OCUOCLÎ is a conmion species foimd in di typa of habitats. In this sndy, P. enacums exacuovr was edlcctd hmrivas, streams, Mes, ponds anâ vernal habitats wbich conam with Clarke's findings.

*Note: Cîarkt (l973b' 1981) uses tht subspcaes P. ex4cuow exacuous and P. exacuow megus to diff'tiste din- pups found in Csneda Thcse subspecics are not rsaguized by Burch

(1989) or Turgccn et ul. (1998), which nfa only to P. ex4cuous. . Planorbula armigera (Say, 1821) Thicklip rams-horn

SITES (2): N1033, NO132 DRAINAGEWATERSBEO ARCTIC: Liard: Fort Nelson (2) ECOPROVINCE/ECOREGION Tiigi Plrios: Hay River Lowlaiid (2) BIOCEOCLIMATIC (BGC)ZONE Bord Whitt and Black Spruct (2)

Fi- A41 - Collection sites for Planorbula amtigem.

Disc~siion: Pliinohda amigem was an uncommon mUusc in northan BC king collectcd hmtwo of 176 sites. These sites were vay close togetha in the northeast of the study ans. It was found only in the Arctic drainage in the Taiga Plains ccopmvince. The BGC in which it was found has a mean annual temperature of -2.9 to 2.VC with up to 7 months klow CPC adup to 4 months above lOOC and with annual pmcipitation ranging hm330 to 570 mm

P. annigera was co11ected hmody one ecologicai site. The meamrements feeorded at this site are shown on Figure 2-12 with a dot.

Enviromta1 Variables: Figure 2-12a shows tbat the tempmtwe measured at the one ecological site for P. amgera is quite high (262.C) sugsesting that it may not be high tanpaatiin tbat limits the distriiution of P. mniigeta in northem BC. Figure 2-12b,c,d shows that the dissolved oxygen, condnictivity/dcium co~tionancl pH meames at this one site wae al within the range those of 174 most 0th- photbids found in this study. This single observation does not supply sufficiait information to hypothesize as to the envircmmtal factors that may affat the distribution of P. annigera in norihem BC.

The mults of the CCA are tbat the Planorbidae are responding sigmfïcantly to the environmental variables @ = 0.005) with 8.8% of the ~iespresence accounted for (Figun 2-18). The measuremeuts hmthe single site for P. annigera does not allow development of a unimodal mp~wto any variable and P. armigera appeam on the plot associatecl with bigha than average temperature. This is in accordance with the fmdings hmFigure 2-12 tbat shows that the most distinctive measurement for this species taken at the single site was that of the high tmipaature.

Clarke (198 1) inâicates that !he distribution of P. omigera includes the far northeast of the study area. This concm with the 6adings of th* stucly where P. annigem was co11ected ody hmsites in the northeast. This distribution, dong with the Merdistribution shown by Clarke (198 1). inâicates that P. annigero may have had its migration hmthe Mississippi nfugc halted by the geographic barrier of the Rocky Mountains.

Clarke (1981) states that P. a-em Liva among vegetation in peiauiial-water habitats especially stagnant, heavily-vegetated water bodies, and Clarke (1979a) states that it is inâicative of eurmphic Mes. In this study, P. annigem was coîiectcù hmvegetation in a large Ucwhae the wata was not necesarily stagnant and hm a Carex msffh in the same ana whcre water conditions are unbtawn. Planorbula campestris (Dawson, 1875) Meadow rams-hom @-ab SITES (5): N1023, N1096, N1097, N1105, NO133

ECOPROmcE/ECoREGION BO- Wb:Peace River Basin (1) SabBorerl Inteaior: Fraser Basin (3) Tiigi Pkh: Hay River Lowland (1) BIOGEOCLIMATK (BGC) ZONE Bord White and Black Spruce (2) Sub-Bord Spnrce (3)

Figure A-32 - Collection sites for Planorbula campestris.

Calcium (ma-) 4 24.46 11.00 12.13 pH 4 6.79 0.52 5.M

Discussion: Plunorbtrla canipesrris was an uncommon moiîusc in nonbcm BC being coiîectcd hmfive of 176 sita. It wa foumi in both the Pdcand Arctic drainages ad in thrce of the six ecopmvinccs. The two BGC zones in which it was found bave mean mual tcsiipaatuics mging hm-2.9 to 5.OOC with up to 7 months klow OOC and up to 5 months above 1O.C and with annuai precipitation mghg hm330 to mmm.

The range and means of the environmental variables mdat the sites whac P. campsrris was coiiccted are shown in Figure 2-12.

Tcm~eratm:Figure 242a shows that P. amigera was found at tcmpaatiircs >2ST suggesthg that high temperature may not k a limiting Wor in the distribution of this taxa. Dissolveci ~XY~CII:Figure 242b shows that P. campesois was collecteâ hmhabitats with a wide range of dissolved oxygeo, dmto levels of <200/0 saturation. This suggests that this species may be oxygen- independent and may be able to occupy a wide range of âabitats in northem BC.

Conductivitv and Calcium Concentration: Figure 2-12c shows that P. campestris was collected from habitats with a minimum calcium concentration of 12.1 mg. Wbile this may reflect a minimum nquirement for this species, the sample size (d)may be insufjFicient to ensure that tbis range tdy reflects the minimum calcium requirement for P. campestris.

Figure 2-12d shows that P. campestrik is one of the frw gastmpods in this study with an acidic mean pH although it was found in both acidic and aikaline conditions. This mean is significantly diffaat from that obtained for P. binneyi Fable 2-7) and th ranges for the two species do not ovalap (Figure 2-12d). However, the sample &es beiag compared (n = 4 and n=2) are too smal to ascertain whether this npresents an ecologicai diffaence betwcen the species or if the ranges accmtely repte~entto tolerances for eithcr spccics.

The results of the CCA are thai the Pbrbidae are responding sipificantly to the environmental variables @ = 0.005) with 8.8% of the specics pnsaice accomtd for (Figure 2-18). Th plot shows P. campestris to comspond to lower tban average coaductivity. The range plot (Figure 2-12c) does not indicate that coaductivity/calcium concentration is a particuiarîy important fadot in the ecology of this specics. Its placement hm on the CCA plot rmiy k due to its small sample size not enabling a mng unimdai mponse to any particular variable.

Clarke (198 1) indicates that the distribution of P. camptris includcs only the fiu eastcm section of the northcm BC. In this study, P. cantpesm was coliedal hmtwo locations in the far sut as weU as hmtwo locations in the south centrai part of the study am thus extcnding the range fider west th was previously rscooded As tbis spccits is llPo known hmVancouver hiand, tbc Yukon, and across camal Canada (Clarke 198 1). there is m clm indication tbat P. campestris migratcd out of any particuiar glacial refiage.

Clarke (1981) States that P. campestris is characteristic of vanal ponds, swamps, and springtime floodcd portions of pernianent wata bodies. In this stuây, P. wmpesbir was coliected hmvd ponds but plso hmparnanent ponds and lakes indicating its habitat may not be as rcsfncted as previously mrded SlTES (9): . N100 l,N1003/CNt012,N1005,N1033,N1084, N1 lO7,NL 1 l2,NOlO6,NOll3 DRAINAGE/WATERSHED PACIFIC; Friser: F~er(Z), Nechako (1); Sktenr: Lakelsc (1) -: Liard: Ft Neison(1); Pace: Pae(4) ECOPROVINCE/ECOREGION Coast & Mountrina: Coastal Gap (1) Sub-lhroll Iatcrior: Fraser Basin (7) Ta@ Ph@: Hay Riwr Lowlaad (1) BIûGEûCLlMATIC ZONE BodWhite and Black Spnice (1) Caastal Westcm Wock(1) Sub-Bonal Spme (7) Figure A-33 - Colleciion sites for Helisom aIuIeps mceps.

Discassioa: Helioma anceps oiiceps wuan u11c0mmon mollusc in ncrthcm BCbeing found at 9 of 176 sites. It was found in both the Pacific ad Arctic drainages in thme of the six aorthem ecopmvinccs. The th= BGC zones in which it was founâ have mean annual tanpaatirrcs ranging hm-2.9 to LOJT with up to 7 months below OOC and up to 6 months abvc lOOC d with annual piccipitation ranghg hm330 to 4400lmn.

The range and meam of the enMr0111llcoM variabies mdat the sites whae H. anceps ancep was coiiected are shown in Figure 2-12.

T-: T-: Figure 2-120 shows îba! H. aweps ancep was founâ at tempaanrns >2S°Csu~gthai Dissolved ûx~pe~1:Figure 2-12b shows that H. anceps anceps was not coliected in babitats where the dissolval oxygen was as low as for some other members of this family. This suggests that H.anceps onceps may be oxygendepenàent. This hypoxia ùitolaance may be a factor that limits the distriiution of H. anceps anceps in northem BC.

Conductivitv and Calcium Concentration: Figure 242c shows that H. anceps unceps was collectd at a minimum level of condudivity/calcium of 16.6 mgtl. It may be tbat H. ancep anceps is limiteci to habitats within aorthern BC that can supply it with this minimum level of calcium.

Figure 2-12d shows that if anceps anceps displays a relatively wide range of tolerance to pH being found in both acid and allialllie conditions. This suggests that pH may not be a limiting factor in the distribution of this spccies in northern BC.

The mdts of the CCA are that the Planorbidae are responding sigdicantly to the environmental variables @ = 0.005) with 8.8% of the spccies prrsaice accoumed for (Figure 2-18). The plot shows H. anceps anceps to correspond most closely to higher than average temperature and lower than average pH. These enviromta1 variab1es, as discusscd above, do not appear to k paiticular importance to the ecology of H. anceps anceps.

Cl& (1981) indicaies H. unceps anceps occ~only in the cast and southe& of northan BC. Whüe this is consistent with most of the co11octions made in this study, an additionai collection was made in the southwcst of the snidy am extending the distribution much fiutha west than previously mrded. This type of distribution pattan gives no cvidence of any barnas imposai during pst-glacial distribution.

Ciarke (1981) states that H. anceps anceps livcs in laka, ponds, rivas and rrtrrpinri. In this study, it was fodonly in lakcs.

*Note: Clarke (1973b, 1981) and Burcb (1989) both use the H. anceps ancep to separate this subspecies hmotha subqmies. Tiirgeon et al. (1998) does not üst subspsEics. Helisoma sp.

sms(1): ml01 1 DRAINAGElWATERSHED bet; Pcace ECOPROVINCE/ECOREGION SubBord Interior: Ftascr Basin BIOCEOCLIMATIC @cc) ZONE Sub-Boreal Spnice

Figure A-34 - Collection site for Helisomu sp.

This record bas bcni included here oniy to providc a coatprchensive record of the spccies collected by Clarke during 1972 cud 1973. While thae is dyonly one specics in the genus Helisomu recognized hmnorthan BC, at the tim of Clarke's coliections, both the specics cumntly rccogoizcd as Plmorbella binneyi adPlamrbella subm~turnwere bluded in the *us Helisoma. Thus, this mrdonly indicates that one of the larger planorbi& wu, colle*cd at îhis site, but does not give any information as O the species. Planorbella binneyi* (Tryon, 1867) Coarse rams-hom

SITES (3): N1082, N1104, CN1017 DRAINAGE/WATERSEED pAcIFIc:Frrser: Nechako ( 1), Sm(1) Skeena: Skccna (1) ECOPROVINCEIECOREGION Coast & Mountains: Nass Basin (1) SubBored Interior: Fraser Basin (2) BIOCEOCLIMATIC (WC)UlNE Interior Cedar - Hemlock (1) Sub-Boreal Spnice (2)

Figure A935 - Collection sites for Planorbella binneyi

Dissolved 02 (% Saturation) 2 85.50 7.50 ~ 78.00 93.00 Conductivityp ( Siemens) 2 119.65 0.05 1 19.60 1 19.70 Calcium (mg/litrt) 2. 16.50. 0.0 1 16.50 16.5 1 pH 2 8.35 0.20. 8.15 8.55 Reviously recordcd clhibution hi northern BC: Far southeast oniy (Clarke 198 1). Discussion: Plonod~ellubiMeyi wuan uncomumn moilusc in norihem BC kiag found at thrœ of 176 sites. It was fodoniy in the Pacific drainage in two of the six ecoprovinces. The two BGC zones in which it was foui have mean annuai tempetaturcs ranging hm2.0 to 8.Xwith up to 5 months below OOC ad up to 5 months above lOOC and with umdpncipitation ranging from 440 to 1200 mm.

The range and means of the aivironmcntal variables masuicd at the two ccological sites whae P. binneyi was coilecteâ arc shown in Figurc 2-12.

Tam~nhm:Figure 2-12a shows tht P. binneyi was cdlccted at a lowa maxiniun taapcrature than wae most species within tbis My. Hawcver, the smail sample &e for this specïes may not give accurate represcataticm of its range of t01crance.

Dissolved ûxym: Figure 242b shows tbat P. bimeyi was colexted ody at sites whm the dissolved oxygcn was quite hi@ This may cornlate with the relatively low t- at which P. binneyi was 181 found. The sample size (n=2) is too small to suggest whether tbis species may be oxygendependent or independent.

Conductivitv and Calcium: Figure 2-l2c shows that the two collection sites for P. binneyi had almost identical conductivities/calciurn concentrations. Howewr, the samples size is too small (n = 2) to piesume that this may indicate the minimum calcium level required by this species. pti; Figure 2-12d shows that the pH at the two ecologicai sites for P. binneyi were both alkaline and were both > pH 8. High pH is associated with high calcium but the sample size for P. binneyi is insufficiait to deany hypotheses about the disiribusion of this species in relation to pH.

The mults of the CCA an that the Planorbidae are responding si@~cantly to the enviro~~mentai variables @ = 0.005) with 8.8% of the spies presence accounted for (Figure 2-18). The shows P. binneyi to correspond to no particular varisbles. The dlsample sue does not dow the development of any measurable unimodal nsponse to these fktors.

CMe (1981) indicates tbat the diseibuiion of P. bimey*includes only the frir southwest of the study arca. This study formd P. binneyi at sites faerwest than indicated by Clarke but di appeais to be confiacd to the Pacific drainage suggestiilg pot-giriai migration hmthe Paeinc refùge.

Clarke (198 1) states that P. binneyt*occuis in euttophic, weil-vegetated IPLcs. Ciarke's collection site for norihan BC (CNlOl7) was such a site but, in tbis study, P. binW was colidhm large, oligotmpbic lrhs with little vegcîation at the collection srras.

*Note: Ciarke (1973b, 198 1) refas to this species as Helisomu nivalvis binneyi. Planorbella subcrenata * (Carpenter, 185 7) Rough rams-hem

PACIFQ Fraser: Fraser (4), Nechako (14), Stuart (4); Na#: Nam (1); Skeeni: Bab& (l), Buikley (2), Skecna (3); SîMnt: Stikinc (1) ARCTIC: Liard: Dew (2), Fort Nehn (7). Liard (5); Mackenzie: Hay (2); Peaœ: Beatton (l), Peace (1 1), Pinc (2) Figure A-36 - Coilçtion sites for Plunorbella subcre~ta. BodPlriiai: Central AlhaUplands (2), Pcact River Basin (2),Soui&rn Alberta Uplands (3) Central Interioc Fraser Phcm (9) Comt & Mo~t.iai:Nass Basin (l), Nass BIûGEûCLIMATK @CC) ZONE Ranges (3), Liard Basin (7) Bord White anâ BkkSpnice (24) SabBod Interior: Skecna Mu. (l),Central Coastal Westcm Hemlock (1) Cluidian Rocky Mountains (l), Frsser Basin (22) ïntaior Cedar - Hdock (4) Trip Phk&y Riva Lowlmd O,Northern Sub-Bord Spnice (3 1) Abcfa UP~(2) Envirolllll~ntrlInformation:

Temperanin (OC) 35 20.89 0.60 12.20 27.20 Dissolveci (% Saturation) 35 67.86 3.15 23.00 98 .O0 ConWvity (psiemcas) 35 26 1.20 35.98 26.70 1199.00 Caicium (m@litre) 35 37.6 1 5.37 2.65 177.44 7.4 1 0.12 5.60 8.90 pH -- - 34 -- ReviousSy reconkd distribution hi northern BC: Throughout mrthan BC (Clarke 198 1).

sites. It was fdin bah the Pacific and Arctic drainages rnd five of the six northem ecopmvinces. The four BGC zona in which it was fdhave man average tempaatures m@g hm-2.9 to 1O.ST with up to 7 months klow OOC and up to 6 months abovt IOOC. Alti- within thesc BGC rimes ranges hm

O to 13000 feet with meen annual pruipitation ranging hm330 to 4400 ~IIL The range and meam of the environmentai variables aPawind at the sites whae P. subcrenata was collected are show in Figure 2-12.

Temperature: Figure 2-12a shows that P. mbcn!~tuwas found at temperatures >25OC suggesting that high temperature may aot be a limiting factor in the distribution of this taxa.

Dissolved Oxym Figure 2-12b shows 16at P. subcre~tawas coliected hmhabitats of nlatively low oxygen saturation (23%)). This suggests that P. subcrenutu my be an oxygen-indcpcndent spccies end cm tolerate hypoxic conditions so that the level of dissolvecl oxygeo of a habitat rnay not be a limiting factor in the distribution of this specinr in northcm BC.

Conductivitv and Calcium Concentration: Figure 2-l2c shows that P. subcre~lawas collected in habitats of vay low conductivity/calcium concentration (< 3 mgii). This suggests that the level of dissolveà calcium in a habitat may not be a Uthgfactor in the distr'bution of P. mbcmnutu in northem BC.

Figure 2-12d shows that P. subcrenuta was fouad over a wide range of pH in bth acidic and alkaliae conditions. This su- that pH may not bc an cnvin,~mcntalvariable that gmtly limits the distribution of this species in northern BC.

The mdts of the CCA are that the Pla~ort,iâacare rrJponding significady to the enviramental variables @ = 0.005) with 8.8% of the spccies p~tsenceaccomted for (Figure 2-18). The plot shows P. subcmnuta to correspond most closely with hi@m tban average watcr tmipaohnc. Fip2-12a did not suggest that tempcraturc might k a particufarly important envirolimcntal variable in the ecology of P. subcrenuta. Its pl~ccmcnton the plot, nba close to the origin but skewed towaràs tqerature may bc of limitai ccological collsc~u~e.

Clarke (198 1) indicates thpt P. mbcre~ioocnÿs throughout nodicm BC which mcwswith the findhgs of this stuày. This widaprrd distribution aiver no evihof any Mersimposeci during pst-@cial distn'busion.

Clrrkc (1981) states that P. mbcrenatu occuis in narly ali pacirnial-wata habitats that support si@cant mted vegctation. P. mbcmllota.was founâ to occilr in these types of habitats in this cumnt dy* FemSsia fiagilis (Tryon, 1863) Fragile ancylid I 1 - SITES (1): CN1021 DRAINAGEWATERSHED PACLFIC: Skeem: Sb ECOPROVINCEJECOREGION Coast & Mountains: Nus Ranges BIOGEOCLIMATIC (BGC) ZONE Inmior Cmtaf Hcmlock

Figure A47 - Collection site for Ferrissicifiagifis.

Previously recorded dirMbutkn in nortbern BC: Nat prcviously recorded (Clarke 198 1) Discussion: Fehsia fiagilis and F. porallelus are both fod in ldc habitats and are mat casiiy dirtinguished on the basis of size (Biirch 1989). F. jugdis nnly exceeds 3.5 mm in lcngth whereas F. prallelus may k up to 9 mm long. AU the FerrrSsia apecics founâ in this study in wrthan BC wac fodin sîancüng wata and all sites gendybad spccimms cxcrcdiag 3.5 mm in kngth. The site where CWe records colloding F. fiagiIis (CN102 1 - Saley LaLe) is the aame site whae F. prallelus was recordeci âuring this stuày (N1091). Thdore, îhere my k sow question as to the idcntity of Ciarke's collection. This may be why Clarke (198 1) chose nat to incluâe norihan BC within the range of any of the Ferrissi4 species hownin Cauada. ClruLe's cohtion should ôe rclexamind to confirm the spcçies identification snd to ver@ whdaor not the range of F.JTogilis extends hto nonhan BC kmit present recordrd Canadiaa distribution of southern Vamouver Isiand and the Lowe Mainlrind (Clarke 198 1). Oblong ancjdid

SITES (31): N1001~1002~1003,N1005,N1006;N1014~1015, NlO26.NlO33,Nt062,N108O,N108 1 ,NlOS4,NlO88, Nlû90,NlW 1,N tO!J2,NlW3,NlO98JUllûûJVl101, N1 lOî,Nlll2,NOLO~~OlO6@OlO?,NOlO8@O t 13, NO1 l4,NOl2l,NOl22

DRAINAGENATERSHED PACIFQ Coast& Nortb Cmt(1); Fnier: Fraser (2), Nechako (8). Stuart ( t ); Nam: Mcaadin(l), Nass (1) Sbm:Bulklcy (4), ïakelse (I), Skna(2) @CTIC; Lhrd: DePx (l), Fort Nelson (1); Pace: Kistatinaw (1), Pcacc (7) ECOPROVINCEIECOREGION Bond Pliinr: Centrai Alberîa UpW(l), Southcm Alberta UpW(2)

N= hgts Figure A-38 Collection sites for Fenissiu pmallelus. (2) - No-rn Bord Mombias: Liard Basin (1) BIOCEOCLIMATIC ZONE (BGC) SubBod Interior. ûmincca Mountains ( 1 ), BodWhite & Black Spruce (5) Fnser Basm (12) Coastal Western Hedock (2) Tdga Phhm Hiy Riva Lowlind (1) Interior Ccâar - Hemlock (4) Sub-Bord Spnice (20) Environmentai Informrtion: ,Me~mmcnt Count Man StdError Minimum MuimPm , TemperatUre (OC) 23 19.92 0.79 . 12.20 26.50 Dissolvd 02 (% Saniration) 23 72.00. 3.55 23.00 9 1.ûû

Conducîivity (psianens) 23 2 14.M ~ 46.80 20.10 1 199.0 Calcium (mrJlitre) 23 27.35 6.29 129 159.73

Prevkiuly recoràed &tribution in northern BC: Not previously recordai (Clarke 1981). Dlscassion: Fenirskz prullelur was a common mollusc in nomBC kgfod at 3 1 of 176 sites. It was fodin both the Pacifîc and Arctic drainages ad in al1 of the ecoprovincs within the shdy am. The fout BGC zones in which it was founâ have mean annal tanparams rianging hm-2.9 to 8.7T with up to 7 months klow OS: and up to 6 moptbs abovc 10°C and with annuai precipitatmn ranging hm330 to 4400 mm.

.The range and the maos of the cnviromiuntal variables at the sites whn F. pom1Ielw was coiiected an show11 in Fi- 2-9. T'-turc: Figure 2-9a shows that F. purallelui was fomd at temperatures >2S°C suggesting that temperature may not be a limiting factor in the distribution of this species in northeni BC.

Dissolved &Y= F. parallel~~is a tnily aquatic puhonate, not dependent on atmosphdc air. Figure 2-9b shows that F. parallelw was colicctcd over a wide range of dissolved oxygen Howeva, at th one site for (bis species where low dissolved oxygen was recorded (23%; next lowest measment 44%), F. parailelus was collected hmthe undersides of lily pads where it would have had acccss to higher levels of oxygea It may be that the F. pamllelu~is an oxygmdependent species and that in habitats with lowa ovdl dissolved oxygen, it selects appropriate microhabitats withia the wata body where sufficient oxygm is available.

Conductivitv and Calcium Concentration: Figure 2-9c shows that F. parallelus was eollected ova a wide range of conductivity/calcium concentration down to abstthe lowest level masurrd in this study. This suggests that the calcium concentration of a habitat may not be a limiting factor in the distriiution of this species in notthern BC. pIi; Figure 2-9d shows thai F. pomllelw was ddovcr a wide rangk of pH kgfound in both acidic and basic conditions. This suggests that pH may not be a Limiting factor in the distri'bution of this opecies in northan BC. In other studiea, F. putaîlelus bas been found at pH ranging bm6.0 to 8.3 (Pennak 1989).

Tai# Wts wae includcd in the Caaonical Comcsporadcnce Analysis (CCA) anaiysis tbat includes F. pomllelus (Group 1; Figure 2-1 5). The resuits of tbis CCA arc that the species an tcsponding significantly to the en-td variables (p = 0.040) with 132% of the specia pnsare rocounîed for. The plot shows F. pomllelw to comspoad mst closdy with Iowa thsn average conductivity. The wide range of conductivitylcalcim comadispiayaî by this specics d~ not indicatc that conductivity is a particularly important ceological Értor for F. pmollehr.

Clarke (198 1) does not record F. parailelus west of Manitoba, which is &O the disüiiuîion givcn by Burch (1989). The only Feni9siiz specics Ciarke iucludcs in BC is F. fiagilis hm southeni Vancouver Island and the Lower Mainland. Clarke, howeva, did collect F. /iogilis hmSeeley Lake (CNlOll) and a FeMasp. hmsimimit hke (CN1021) (Lee and ~ckemuui1999a).

F. pcvollelw was corttmnn in this shufy, most oAen in the south of the stuciy ana but with a few coktio~sin the d It is possibk tht this ümpct is migising northwards, patirps hmboth the Pxific aad Mississippi rd'ugb, ad has to date dysuccessfiilly colonized large lake in the no& of the stuây area. This widesprcaâ distriion of F. pomllelvr giva no indication of any bernas it mwuniaed during dispasal. In eastan Canada, Clarke (198 1) found F. parallelus to live in Mc&, swamps, adslow-flowing rivers among thick or moderately thick vegetation and that it was oAen found on the stems of cattails (Tm)and sedges (Scirpils) or on the unclmides of üly pads. in this study, F. parallelus was found in simüar babitats. most oRen on the undersides of Mypack, but also oAen on the dersides of rocks and on submerged wood

*Note: This species is referred to as Feniisa purallela by Clarke (1973b. 198 1). Funiiy Ancylidic FenWio ip. Femksio sp.

ECOPROVINCE/ECOREGION SuitBord Interior: Ftaser Basin BIûGEûCLiMATIC @cc) ZONE Sub-Bord Spnice

Figure A939 - Colicction sites for Ferrissirr praIIeIus.

Rwioosly recordcd distribution i northem BC: Not pmiously recordai (Clarke 198 1). Discusidon: Cluke (1981) does not iaclude northcm BC within the mge of any of the Fedia species hown hm Canada aithough this record (coiieaed in 1972) indicatcs that Ciarkc was aware of the occurrence ofFe&sia in northcm BC pnor to publication of the dtsof bis stwly. Margaritifere falwta (Gould, 1850) Western pearlshell

SITES (8): N1083/CN1022~1094,N1095,Nl113*, N0101,N0123*,N0124*,N0140* *shdls only found or thae sita DRAINAGENVATERSHED PAClFïC: Fraser: Frwr (3), Nechako ( 1 ), Stuart (1); Skeenr: Babine (1), BuWcy (1), -lse (1) ECOPROVINCWECOREGION Centrd Inter& Frascr Plam ( 1) Coast & Mountains: Nass Ranges (1) Sab-Bord Interioc Fraser Bash (6) BIOGEOCLDUTIC (BGC)ZONE Coastal Western Hedock (1) Sub-Boreal Spruce(7) Figure A40 - Collection sites for Margaritr~erufülcata.

Enviionmentai Informatioa: ,

T- T- (OC) 4 15.18 1.89 9.60 17.90 Dissoived 02 (% Saturation) 4 69.00 5-18 55.00 80.00 Conductivity (~Siewns) 4 144.63 39.09 67.80 213.00 Calcium (mnllitrd 4 20.23 5.83 8.77 30.42

Discussion: Margarin@ra /oIcata was an uncommni mo11usc in nonhan BC kiag fouad at cight of 176 sites. It was fdonly in the Pacific drainage and in the thiee souîhniltn~stecoprovinces in the dudy arca. The two BûC zones in which it wrr fouud bave wan annual tcmperatures rmging hm 1.7 to 10.5% with up to 5 months below 0.c and up to 6 months abovc 10.C with mual precipitation ranging hm440to4400mm.

The range anâ means of the environmental variables at the sites whm M. filcuta was collecteû are shown in Figure 2-13.

T-: T-: Figure 2-13a shows tbaî M. falcota was coliected hmsites where the temperature was gendy lowa than that for mst of the osha bivaives in this pup. The mean temperature for M. focata was si@dy lowa than for the olhcr fhshwaîa musse1 ni northem BC,A. bnnerb {Tabie 2- 7). This is in accorciawe with the différent habitats of these two speeies.. M. focuta is a lotic species found in running ~ueam~wider than four meters (Clarke 1981), whaeas A. kennerlyi is a lmtic species fouad in lakes in this shdy. The taapmuurr in fiowing water would generally be lowa than that found in standing water.

Dissolvecl &Y= Figure 2- 1 3b shows that M. facata was ody couected hmhabitats of relatively high dissolvui oxygcn. M. falcata may k icseicted to lotic habitats by its need for oxygen (Le., oxygendependent), or it may be restricted by ohm factors, and bigh oxygen is an intrinsic factor of these habitats.

Conductivitv and Calcium Concentration: Figure 2-13c shows that M. falcata was collected hmhabitats with a minimum calcium concentration of 8.8 mg/i and that it was collected ova a vay limited range. This limited range may be characteristic of Pacific drainage systans Wor it may be that M. fülcuta is restrictd to streams pmviding this minimum level.

Figure 2-13d shows tbat M. filcata was found in bah acid and allraline conditions. This suggests that the pH of a habitat may not k a limiting faetor in the distribution of this spies in northan BC.

The results of the CCA are that the large bivaives an not responding siBnificBadly to the environmental wiables @ = 0.480) with 5.1% of the species pnsare accounted for (Figure 2-19). Howeva, the placement of M. /ocata on the plot corresponds to lowa than average temperature, which

is in kecpiag with th ecology of this @*r.

M. fikata is lmown only hmthe Pacifïc drainage in western North Amcrica (Burch 197Sb), whch suggests thaî M. @cura dispaKd hmthe Pacific Refhge, and Clprlre (1981) lists it as a species charactaistic of this type of disperd. Rior to this study, M.falcata was known in nonhan BC frwi only one site, the Lelalse Riva ncar Temce (Clarke 1973% 1981). Tbis shidy, while mt extending the rans much Mnnorth, extmds the range much fartha east within the Pacifie drainage. M. falcata would rppar to noch its mrthan limit with the nir south of the shdy ana yet Bmh (197%) States that it is also foud in southm Aiaska. As the distn'bution of Mwatcr mussels is linked to the distribution of th& host fishes, it msy k conditions suitable for the host M that linrit the distn'butîon of M. focatu in aorthern BC . Flinily UnionidK Anodonro &mer@ Anodonta kennerlyi Lea, 1860 Western floater SlTES (22): Ni~,Ni~1,~1003~m1012, N1005,N1082,NlO84/MN10 14,Nl088,Nlû96, NI lOO/CN1020,N1104,N1105,lU1112~0102, NOlO6,NOllO,NOl 13/CNlOI1~01l4,CNlûû2, CN1017,CN1018,MN100S~1008

DRAIIYAGWWATERSIIED PACIFIC; CoutrkNorh Coast (1); Fmler: Fraser ( l), Nechako (8), Stuart (3); Skeem: Babiac(l),ïakclac(l),Skecna (l),Sustut (1) ARCTIC; Perce: Peacc (5)

Centrai Interior :Frarier Plsti.nu (5) Coid & M0~11t8ins:NassBasin(l),Co~tstal Gap(2) Subhdinterior :Omiucca Mountains (k), Fraser Basin (13)

Figure A41 - Coliection sites for Anodonta knnerfyi. Coastal Western Hemlock (2) Intaiot Cedar - Hcmlock ( 1) Sub-Bord Spluce (19) Enviramentai Information: Measurcmtnt Couat Meui Stà.Emr Minimum Mhum , Temperahin (OC) 12 20.34 1.O4 16.20 26.50 Dissolval O, (% Sahaaiion) 12 76.92 3.80 44.00 93.00 Conductivvity (psimieas) 12 135.78 14.63 20.10 203.00 Calcium (ma-) 12 18.9 1 2.18 1.@ 28.93 b~ 12 7.34 0.29 5.25 8.55 ktviously recorded distribution in northeri BC: Fmfar south of shdy ami (Clarke 198 1). Dbcu~sion: Adon& kd)iwas a coamwn moliusc of northem BC beiag founà at 22 of 176 sites. It was fouid in both the Pacific and Araic drainages in the southcrnrnost acopn,vimes of the sRidy arca. The thrtt BGC mats in which it was foui bave man mual tanpcratures mghg bm 1.7 to 1O.K with up to 5 months klow OOC and up to 6 months above 1o.C with armual p&ipitation raflging hm440 to (4400 mm.

The range and meam of the environmental wiables at the sites wbcn A. AelllterIyi was coliected are shown in Figure 2-13.

Tamaatwç: Figure 2-13a shows thaî A. knnerfji was coilected hmsites whae the tanpaaaire was rehtiveiy hi@ The mean tanpcninuc fot A. hmeriji was forad to bc sipiiïcantîy higher tbari for M. facatu fiable 2-7). This is in accordance with the différent habitats of thse two spccies. A. keMerlyi is a lentic species found in lakes within the study amwhercas M.folcata is a lotic species fo'iin nianiag streams wida than four meters (Clarke 1981). The tcmpasture in standing water might generally be hi* than that found in flowing water leading to the signifiant difference of the means. The hi* teinperature et which A. kennerlyi was collected suggests that tempetanire may not be a factor that limits its distribution in northem BC

Dissolved Oxv= Figure 2-13b shows that A. kennerllyi was only collected hmhabitats of relatively high levels of dissolved oxyeai, which suggest it may be an oxygendependeat species. However, Lewis (1984) found that another Anodonta species, A. grandis, was oxygen-independent, being able to maintain nearly constant oxygen consu~llptiondown to vay low levels. It may be that A. kennerlyi also has this ability but tbis was not reflected in the oxygen content of the habitats b which it was found in northem BC.

Conductivity anà Calcium: Figun 2-13c shows that A. Aennerlyi was collected hmhabitats with a minimum dcium concentration of 1.7 mgll, which is close to the minimum recordcd in tbis My. This su- that the conductiviitycalcium concentration of a habitat may not k a factor that limits the distribution of A. &amer& in northem BC. a Figure 2-1 3d shows that A. kenneriyi was collected hmhabitats with a wide range of pH includiag both acidic ad altaline conditions. Tbis su- that pH may not be a f~orthat greatiy kitsthe distribution of A. Aennerlyi in noxthcm BC.

'Ibe dtsof the CCA are tht the large bivalves are not responding signincantly to the environmental miables @ = 0.480) with 5.1% of the spccies picscire accounted fa (Figure 2-19). Howms. the placement of A. knnerl' on the plot correspoxxis with hi* than average dissolved oxygen, which is in keeping with otha chta hmthW stuây.

A. Aennerlyi is hown in Cana& hm ~oscsouthem BC anâ into west centrai Albata and extends southw8 in the Psciac &aiuagc to Oicgon (Clarlrc 1981). This distn'bution pman suggcsts dispcrssl hmthe Pacific Refbgc. Howeva, unlike MJiilcata, which is klieved to bave a similsr migin, A. Aennedyi ais0 also in the Arctic drainage in BC and Albata. The disûiiution of Wwater mussels is linked to tbat of th& fish hosts (Wattas 1992) ad it is beiievcâ tbat the e~sryof Pdcspccics of fish into the upper Pace is dw to a rehtivcly ment mimr hcaâwater transfn, as few species bve dispased much faiiha down the Pewe th to the Albcrta(BC border (McPhaii and LtndKy 1970). It may k tbat and the headwater transfer may have kludcd A. AewrZyi or fisb carrying their @ochidia as this is the dimikiton pattern mrdedby Ciarkc (1981), which arriirs with the nndings of tbis sndy. Sphaerium nitidum Westerlund, 1876

SITES (18): N1004,NlOl l,N

ECOPROVINCE/ECOREGION Boml Plrini: Central AIbnra UpW(1). MuhmPintrnli (l), Southern Alberta Upiands (2) Centrai Interior: Fraser Plateau (1) C08N & MountiiPs: Coaatai Gap (2) Northern BadMountrinr: Nonhm Canadiao hkyMouutaius (1), Bord Mountaias Figure A42 - Collection sites for Sphaerium ni*m. and Platmus (3). Liard Basin (3) BIOGEOCLIMATIC ZONE SubBodInterior :Skma Mountains (1), BordWhite and Black Spme (12) CdCadian klryMts. (l), FmBasin (1) Coastal Westan Hedock (2) Tdga W.Hay River Lowlard (1) Intaior C* - Hadock (1) Spnice - Willow - BVch (1) Sub-Bomd Sprue (2) Environmentai Informrtion: Meumment Comt Mtrn Std.Error Minimum Maximum Tempaatureo 14 19.62 1 .O2 12.20 26.20 Dissolved 4 (% Saturation) 14, 66.86 5.02 23.00 99.00 Coductivity (psiemens) 14 280.2 1 87.70 19.70 1199.00 Calcium (mfltre) 14 40.44 13.08 1 .60 177.44 pH 14 7.09 0.23 5.25- 8.15 Reviouaiy no~rdtddhhibutlan hi northtill BC: hughout northem BC (Clarke 198 1). Discussion: Spiurenenumnitidum wes a common moiiusc in northcm BC Mgfound at 18 of 176 sites. It was fomd in both the Pacific and Arctic Qainages in all of the a~pvinces.It lacks only in the ESSF BGC zone, which is the last rcprcsenteù in this shdy. The five BGC zones in which it Qes occur have man annual t~mpaanircsnmging hm-3.0 to 10.s.C with up to 7 maths bdow OOC and up to 6 monnhp ahWC with annual pncipitation ranghg hm330 to 4400 mm.

coliccted arc shown in Figure 2-13. Tamerature: Figure 2-13a shows that S. nitidtrm was coiiected at temperatures >2ST suggesting that temperature may not be a limiting factor in the distribution of this piesin nonhem BC.

Dissolved Oxv~ai:Figure 2-13b shows tbat S. nitiàùm wm collected in habitats with dissolved oxygen saturation dom to the lowest measUrcd for other bivalves in this gmup (23%). According to BuiLy (19833, Sphuenum spccies are oxygendcpmdent but can estivate unda hypoxic conditions. Only one site with rclatively low dissolved oxygen (23%) was measuted for this species, with the next lowest site having 44% oxygen saturation. As Burky has exainineci the oxygen physiology of Sphuerim species, it may be assumed that the one low messurr recorded in this study may not k indicative of the usual conditions under which this species is fod,or that the spccimais collected were estivating.

Conductivity and Calcium: Figure 2-13c shows that S. nitidum was collected in habitats where the conductiivty/calcium concentration was the lowest measured in this study. This suggests tbat the distribution of S. nitidum in notthern BC may not k restricted by the level of conductivity/calcium of a habitat. p& Figure 2-13d shows that S. nitidrrm wu collected ova a wide range of pH, in bot'acidic and aikahm conditions, and at the lowest value mcasured for this gemia This suggests that pH may not be a faor that greatly limits the distribution of this species in porthem BC.

The dtsof the CCA arc that the kge bivalves arc not rcsponding significratly to the enviromta1 Vanables @ = 0.480) with 5.1% of the spccies pcsare ~ccountadfor (Figue 2-1 9). The phcement of S. nitidun on the plot corresponds to Iowa tban average pH, which may be of iimited ecological importance to this spsia.

Clarke (1981) Uidicates tbat the range of S. nitidum inciudes ail of northem BC, wbich is consistmt with th fhhgsof this study.

Clarke (1979% 1981) states tbat S. nithhm is a cold-wata spccies that ocairs in Mes and rivas and tht it is an indicaîor specics of oligotmphic iakcs. In this study, S. nitidurn was often collected hm large oligoircsphic îakes, but was ahcollectai hmmcsotrophic laka anâ hmponâs. Spkerium rhomboideum (Say, 1822) Rhomboid hgernailclam

DRAINAGWATERSHED PACIFIC: Fnrcr: Nechako (I), Stuart (1) Skeenr: Bulldcy (1)

Centnl lnttrfor :Fraser Plateau (1) SubBod Interior: Fraser Basin (2) BIOGEOCLIMATIC (BGC)ZONE Sub-Boreai Spnre (3)

Figure A43 - Collection sites for Spherium rbmboideum. Environmentai Information:

Rtviousiy neordcd diatribution in nortbtm BC: Not pmnously recotded (Chukt 198 1). D~cuasion: Jipiraerium rhomboicieirm was an uncommon moiiusc in aorihm BC king collectai at only thrcc of 176 sites. It was found only in the Wifk drainage in the interior ecop~o~.The BGC zone in which it wufod has mean annuai tdm~~~tll~~rangîng fiom 1.7 to 5.0 OC with up to 5 montbs below 0.c ad up to 5 months above IOOC mi with anmal prsipitation of 440 to 990 mm.

S rhomboideum was ody coileclcd hmone ecologicai site. The values of the enviromentai variables mdat this site arc indicatad on Figure 2-13 with a dot.

VmFigwc 2-13a shows thas the taqaatm rit which S. rtiomboiderrm was coiîcctd is within the range of the tempaatia*l recotded for most otha bivalves in this group. Figure 2- 13b.c.d shows that the site at wwbich S rhombohm was coIIectd hd reiaîîvely hi@ masures of dissolvcd oxy- COIbdUCtivityIcaicium concentration and pH. Thae single ducs gives no indication of what the range of tolerance to these variables may be for this species, and so docs not aiiow the formation of any ecological hypotheses.

The resuits of the CCA an that the bivalves in this group are not responding siphntiy to the environmental variables @ = 0.480) with 5.1% of the species prrsenee accounted for (Figure 2-19). The placement of S. rhomboideum on the plot corresponds to higkr thsn average dissolved oxygeu but is of limited ecological interpretability due to the small somple size.

Clark (1981) does not include nonhm BC within the range of S. rhomboideum. S. rhomboidewn has bem found in 0thpmvinces ody as far mrth as it was in Usstudy. This, the distribution of S. rhomboideunr in northem BC may be limited by cbticrestrictions.

Clarke (198 1) describes the habitat of S. rhomboideum as lakes, ponds and srnaniS. In this study, the three sites for S. rhomûoidetrm were a laLe, a pond and a stream. Sphaerîum simile (Say, 181 7) Grooved hgemailclam

DRAINAGWATERSHED PACLFIC: Fnbcr: Fraser (1), Nechako (4), Stuart (1); Naas: Nass (1) ARCTiC:Ulrd: Fort Nebon (1); Pace: Peace(5)

Bord Plains: Southeni Alberta Uplands (1) Corit & Mountrinr: Nass Basm (1) Sub-Bord Interior= Fraser Basin (10) Tdga Pb:Hay River Md (1) BIOGEOCLIMATIC (BGC) ZONE Boreal Wbite and Black Spme (2) Interior Cedar - HemIock (1) Sub-Boreal Spruce (10) Figure A4- Collection sites for Sphaerim simile. Environmatai Information: ,Meaaunment Count Mern StdEmr Minimum Maximum Temp~ra~(OC) 8 21.06, 1.57 14.00 26.20 Dissolved 4(% Saturation) 8 70.38 6.45- 32.00 90.00 Conductivity (psiemens) 8 176.86 11.35 120.10, 227.00 Caicium (mfltre) 8 25.03 1.69- 16.57 32.5 1

Revioaaty recorded dlrtribution in noitbern BC: Not previously rccorded (Chkc 198 1). Dbcussion: @hoerium simife was a conll~nmllw in mrthcni BC bang foimd at 13 of 176 sites. It was found in Wh the Pacific and Arctic drainages in four of the sin noficm dcoprovinces. 'Ihe tbice BGC zona in which it waa fdhave mean mual tcmpaatiites ranghg hm-2.9 to 8.79: with up to 7 months below 0.c and up to 5 monîhs above 10OC anâ with annuai precipitation mging hm 330 to

The range and mean of the environmental variables measimd at the sites where S. simile was

Tcmmîun: Fi- 243a shows that S. side was coilectai ai tanpcntiir*l >2S°C suggesiing that tempcratm may not be a ümüEg fhctor in the disûi'bution of tbis species in northern BC. Diswlveâ OxymSphuerium species are described as king oxygnidcpeadent (Burlry 1983). Fim2- 13b shows that S. simile was collected at a minimum disoolveà oxygen saturation of 32%, wwbich =y be consistent with requimnents for relatively hi@ levels of dimlved oxygen.

Conductivitv: Figure 2-l3c shows tbat S. simile was found down to a minimum of 16.6 m#l calcium. This suggests that the distribution of S. simile may be lmiited by the level of conductivity/calcium of a habitat, and that this may affect its distribution in noahan BC.

Q& Figure 2-13d shows that S. simile was found in both acidic and alkaline conditions but within a relatively limited range. It may be that S. simile is unable to tolerate exûeme pH habitats, which may restrict its distribution in northern BC.

The dtsof the CCA an that bivalves in this grog are not tesponding sipificantly to the environmental variables @ = 0.480) with 5.1%of the spscies pnsare accounted for (Figure 2-19). The plot shows S. simile to correlate most closely to higha than average tempaahirr. As pcr the above discussion, tempcfaturc does not sean to be a particuiarly important ecological for S. simile and its placemant hac on the plot may be of limited cfologicai importance.

Clarke (1981) does not include northem BC within the distribution of S. simile. Most of the coiiacticms of S. side madc during this study wae madc in the southeast of the study am,exicnding the range indicatd by Clarke oniy siightly northward. Howeva, tbae was also a coUcction dein the northcast ad mother in the soushwest of the shdy arcs, which changes Clrike's rccorded distriiution consihbly.

Clarke (19794 198 1) describes S. simiie as Occumng in aU kinàs of paeanirl wa!a habitais and tht it is an Wcator species of eutrophic b.In this study it was oAen found in hgc oligotropbic to mesotrophic Mes and in the slow moving amof stmms, as weîi as in somc eutrophic wata Mes thus, it has a much broada habitat range than has beai previously indicated. . Sphaerium striatinum (Lamarck, 1818) Süiated fingemailclam I-*- SITES (1): NI107 DRAINAGEJWATERSHED PACIFIC: Fnser: Fraser ECOPROVINCEIECOREGION SubBoteirl Interior: Fraser Basin BlOGEoCLIMATIC (BGC) ZONE Sub-Bord Spnice

Figure A45 - Collection sites for Sphaenum shiotimrm. Environmentai Information: Memurement Count Observtd Tem~~m~e(OC) 1 14.00

Discussion: Spherium simile was an ~~IImollusc in northeni BC king fodai one of 176 sites. It was founâ ody in the Pxific &aime in the Sub-Bonal Interior ecoprovince. The BGC zone in which it was found has a mean annual taipaiiarn ranging hm1.7 to 5.O.C with up to 5 months below OOC and up to 5 montbs above lODC d with rnmd pmipitation ranghg hm440 to 990 mm.

S. saU>tinum was only coilectd one ccologicai site. The values of the environmental miables mcaswcd at tbis site arc indicstd on Figure 2-13 with a dot.

Variables: Figun 2-13a shows that the one measuranent available far S. striatinum is nlativdy low. However, if hi& tcmparnin wac a limiting fiadot for S striutinum, it would k expected to k more conmion in the nonh of BC than in the south. As chis is not the case, intolaence to high wata taqmtim may not bc a Mtbg factur in tfic tktfiiutim of this spccies in northera BC. Fi- 2-13b shows that the one nmmmmuûof dissolved oxygcn for S. shtinum is rclatively hi& and Figures 2-13c,d show that the measiaa for bth conductivity/calcium concenüation and pH an within the range of most otbn Sphaaium species in this study. These single values gives no indication of what the range of tolnance to thcse variables may be for this species, and so does not aiîow the formation of my ecological hypothes~~.

The results of the CCA are that the bivalves in this group are not responding sipificantly to the environmental variables @ = 0.480) with 5.1% of the piespresence accounted for (Figure 2-19), The placement of S. sniatimm on the plot corresponds to lower than average temperature, but this is of limitad interpretability due to the small sample sue.

Clarke (198 1) includes the castan ana of nortbern BC in the distriiution range for S. saiorinum but no records could be found to support this. However, the collection made during tbis study in the southeast of the study area concurs with the distribution indicatd by Clarke. This one record for northern BC giva no indication of possibie pst-glacial dispasion routes.

ClarLe (1979a, 1981) describes S. striatinum as living principally in rivas and stmms but dm ocnirring in large lakes and mly, in small laka aud that it is indicative of mcsotrophic laka. In this study, S. shiobnum was collected hma large Me where it was found in the mots of aquatic plants ncar the shore. Family SpblQÜdK Muculium locune Musculium lacustre * (Müller, 1774) Lake fingernailclam SITES (40): - N1010,N1012,N10lS,N10ZO,N1027,N1028,Nl033, N1034,N1036,N1037,N1038,N1039,N1040,N~041, N1042,N1043,N10!54,N1055,N1059,N1072,N1084,

DRAINAGWWATERSHED PACmCoortri: North Coast (1); Frucr: Fraser (2), Ncchalro (4), Stuart (3); Sknr: Babinc(2), Bulldey(Zj,Lalrtlse(l),SLccna (3) Stildne: stiirine (1) A.RCTIC: Lhd: Deas0 (l), Fort Nelson (9), Liard (2); Miclcemie: Hay (2) P~CCBeattun(2), Haifway(l), P@2),Pine(2)

BoW Plains: Central Alberta Uplaads (3), Soutbm Alberta UpW(4) Figure A46 - Collection sites for Murnlliuni lacustre. Centrai Interior= Frsset Piatreu (4) Coiit & Mts.: Coastai Gap (2)3ass Ranges (3) BIOGEOCLIMATIC (BGC) ZONE Northern BadMountrina: Bartal Bord White and Black Spruce (2 1) Mountains and Piatmiu (l), LîdBain (3) Coastal Waian Hanlock (3) SubBore8i Interior :Cemai chadhn Rote Engelmann Spwe - Subaipine Fir (2) Moimîains (I), Fraser Basin (8) IntGor Ce- Hcmlo~k (2) Tdfpptrinr: Hay River Lnwlrid (9), Norrhan SubBod Spnre (12) -UP~ (2)

Dissolved (% Saturation) 33 66.99 3.36 25.00 93 .O0 Conductivitv (usiemensl 33 254.90 34.85 20.10 987.00

Calcium (@th) 33 36.67 5.20 ~ 1.66, 145.83

PH s 32 7.22 0.13 5.25 8.75

Prtviot~slyrecordcd dhtribution h nortLern BC: Far erst only (Cîarke 198 1). Discussion: MwcuIirn, lacustre was a common moliirrc in northcm BC being foui at 40 of 176 sites. It was found in both the Pacifïc and Mcdrainages in aii of the ccoprovinces. It was fod in aîi but the Spruce-Wiuow-Bkh BGC zone. The five BGC zones in which it was found bave mean amid taiipennncs mghg hm-2.9 to 10.5T with p to 7 monstiS below 0°C and up to 6 months ahLOOC and with armai precipitation ranging hm330 to 4400 nm~

The range and mean of the environmental variables measured at the sites wbac M. lacustre was Tmioctan~e:Figure 2-13a shows that Iucutre was coliected at temperatures >EC suggesting that hi@ temperature may not be a limithg factor in the disiribution of this species in northem BC.

Dissolved OxvmFigure 2-13b shows that M. lacustre was collected over a bmad range of dissoived oxygai but was neva found in habitats of very low dissolveci oxygen (i.e., ~23%).Muculium species have been described as oxygendepenâent (Burky 1983), which may be consistent with the hdings of this study

Conductiviitv: Figure 20th shows that M. lacu~newas collected at sites with the lowest conductivity recordcd in this study. This suggests that ccnductivity may not be iimiting factor in the distribution of this species in northem BC.

Figrin 2-13d shows that M. lacustre was collecteci over a broad range of pH, in both acidic and altaline conditions. This suggests that pH may not be a fador tbat ptly limits the distribution of this spocies in northem BC.

The resuits of the CCA an that the bivalves in this group are not respoxuiing signindy to the mviroIllIlcafal variables @ = 0.480) with 5.1% of the species pmence accounted for (Fi- 2-19). The plot shows M. lacustre to correspond most closely with higher than average couductivity. The above discussion does not indicate that this may k of any partrcular importance in the ccology of M. lacustre in thst it was found in vay low conductivity habitats.

ChiLt (1981) indicates tbat M. lamm OCCUR in northan BC only in the castan ara. In this snidy, M. lamm wss foimd most coirimnnly in the eut, but was found througbut the study am thus expPadiae the range mch fiiRher nor& and eut in BC thrn that rangt indicated by Clarke. This widesprrad distribution givcs no Mcation of my kmas imposai during pst-giaciai dispersion.

Clarke (1981) dcsaîks the habitat of M. lacustre as pamnial water lakes, pod, rivers ad strcams which ooncurs with the types of habitats in which M. Qouhe was fodin this study.

*Note: This genus is refdto as Sphaerium by Clarke (1973b, 1981) and Harington (1962) but otkr authors use MwcuJium (Buch 1975% Twpnet 1 1998). F&ly Spbraik MwcvlUm seCuris Musculium securis * (Prime, 1852) Swamp fingernailclam SITES (46): ~iooi,~1o02,~1005,~1012, NlOLO,NlO26,NLO27,NlO3l,NlO33,NlO39,NlO48, N1052J1053~1058~1059,N!062,N1066~1069, N107S,N1077,N1084,N1085,N1088,Nl090,N1091, Nlo92~lW3Jlo96~1097~l098,N1~ûO~llOl, NI 10431 L07,NlllO,Nllll,NOlO2,NOlO3JOlO4, NOlO8,NO109,NO113,NO115,N012O,NO127,NO129

DRAINAGWWATERSHED WIFIC; Cmatd: North Coast (1); Fnwr: Fraser (3), Nechako (6), Stuart (4); Nam: Mcziadin (1); Skctrn: Babine (S), BWey (3), Lalrelse (1). SkeeM (3); Stitine :Stikine (2) ARmC: Liard: Derce (4), Fort Neïson (2). Liard (3); Mackenzie: Hay (l), Pace: mon (1 ), HalfWay ( 1)J'- (5)J'k (2)*Smb( 1 ECOPROVIlïCE/ECOREGION Bord Pi&%: Peacc River Basin (l), Southcm AlberCa upw(2). cenîral Alberta Upl8ds (3) Figure A47 - Collection sites for Mwculium secad. Centrd Interior: Fraser fiatrnu (5) BIOGEOCLIMATIC (BGC) ZONE Coliit & Moantriiu: Naas Basm (l), Cmstal Bord White and Blaek Spmc (17) Gap (2). N= Ranges (3) Coastai Western Hemlock (3) Northern BordMomtrin~: Bord Engelmann Spm- Subalpine Fir (2) Mombhand Pbaua (2), Liard Bmin (6) Interior Cedar - Hemlock (4) S~b-BoiurlInterior: Slreeaa Mountains ( 1 ), Sub-Bod Spwe (20) Fraser Basin (1 S),Ccntral Canadian RocQ Mu. (2) Hay Environmentai informrtion: Td~pW. River Lowiaod (3) ,Maauremnt Count Mem Stâ.Error Minimum Muimum , Temperaturt (OC) 36 19.62 0.60 12.10- 26.50 36 7 1-24 3 .O2 23 .O0 98.00

Pnvioudy recordcd dliâribudon in northern BC: Not pmiously recordeci (Clpikt 1981). D~cauion: Mvrculiun securis wuis a co-n mliusc in northcrn BC bchg foimd at 46 of 176 sites. It was fouid in both the Pacific and Arctic bainages in aii of the ecoprovinccs. It was found in aii but the Spruce-Willow-Birch BûC zone. The five BOC zones in which it was found have mean annual tempatms mghg hm-2.9 to 10J.C with up to 7 monîhs klow OOC and up to 6 months above lODC and with cnmusl precipitation mging hm330 to 4400 mm.

The range and mean of the environmentai variables masincd at the sites whne M. secvris was coUet%l arc shom in Figure 3-13. Temberature: Figure 243a shows that M securk was collected at temperatures >25*C suggesting that high temperature may not be a Iimiting factor in the distriiution of this species in northem BC.

Dissolveci Figure 2-13b shows chat M. secuBs was collected ova a bdrange of diseolved oxygai but was never found in habitats of very low dissdwd oxygen (Le., Q3%). Mu~culiumspecies have been described as oxygendependent (Burky 1983), which may be consistent with the findings of this study

Conductivity: Figure 2-13c shows that M. seeuris was co11ected at sites with the lowest conductivity recorâed in this study. This suggests that conductivity may not be a limiting factor in the distribution of this species in northern BC. g& Figure 2-13d shows that M. secud was collected over a broad range of pH, in both acidic aad Wineenvimmnmts. This suggests that pH may not be a factor tbat greatly limits the distribution of this spccies in northern BC.

nie results of the CCA arc tbat the bivalves in this group are not responding signifïcantly to the environmental variables (p = 0.480) with 5.1% of the species ptesence accounted for (Figue 2-19). The plot shows M. seadto correspond to no pacticular environmental variable as it occurs on the plot vay near the ongin of al) the variables.

Clarke (198 1) das not include northan BC in the range of M. securis although its range includes most of northcm Al- into the Nortb West Tenitories. This stuciy fouad that M. se& was commn thmghou! mrthcrn BC, which extmdp th range for this specics coasidaibly nofi d west in BC. This widespread distriion givcs no inâication of any barrien imposcd during poat-glacial dispasion

CMe(1981) dcscribcs the habitai of M se- as both vdand.pagmil wata habitats such as lakes, ponds, rivers d stmm. in this stuây M. se& was foui primMy in laka and ponds with oniy two records hmthe slow moving amas of strcams.

*Note: This genus is refdto as Sphuerium by Clarke (1973b, 198 1) and Henington (1962) but other authors use Mdium(Bmh 19754 Tingeon et al. 1998). Musculium tranwersum * (Say, 1829) Long fingemailclam

Sub-Bord Interior: Fraser Basin

Figue A48 - Collection site for M~(sctlliumfmnsvemm. keviousiy rtcorded distribution in norcbern Bc: Eastern ana (Clarke 198 1). Discussion: Ciarke collectai this spccies in no* BC during weys in 1972. This species was not coiieaed during the beurse of this study. It is included here to give a syaoptic mord of aU of the firesbwater aaolluscs hown hmnorthcrn BC.

*Note: Refdto by Hariagion (1 962) and Clarke (1973b, 198 1) as Spherium mllpversum Pisidium casertanum (Poli, 1 791) Ubiquitous peaclam

DRAINAGE/WATERSHED PACIFIC: Coutil: North Coast (2); Friser: Fm(S), Nech(6), Stuart (5); ~SS:Beil-Mg (l), MePadin (1); Skm: Babine(2),Buikiey(Z), Laireise( l),Sirana(4);Stikine: Iht(4), Stilriae (3); Yukon: Ath(1) ARCTIC: Lm:-1 l),Fort Nchn (8), Figure A49 - Coiiection sites for PIridium casertanum. Kechilca (1)Jiard (7),T084(1); Macicede: HayI2) Pace: Beatton (1 ), Fialay( l),Hahay (l),Peacc (7, BIûGEûCLIMATIC (BGC)UlNE Pb(31,Smky (1) BodWhite aad BkkSpruce (41) Coastai Western Hemlock (4) Bord Plliinr :Peace River Basin (2), Cd EngeInuuui Spxucc - Subaipine Fir (2) Alberla UplnndP (3), sou!hern Albertr upw(3) Cadar (6) Interior - Hemlock Cenawl Interior: Fraser Platmri (6) (5) Spnicc - Wiow - Birch Cd& Mopntrinr: Norrhern CdMm. (1), Suô-Borcai Spnre (23) CdGap (2),Nass Basin (2),Nam Rangea (3) Noitbtlp BodM01ult8h: Hytad Highbd (i),tiordBasin(lO)~MormtaiiiiliindPlatrria , (16), Eiorthcrn Cadian Rocky Moh(2) SubBord Interior :Sb Mountains (2), Fraacr Basin (lS),Ccnaat Caadian Rocky Mountains (2), omkca Mm- (2) Tdp PhkNonbem Aiberta UpW(2). Hiy River LnwW(3), Hay River bwland (4)

Calcium (mflttt) 61 34.28,- 3.45 1.66 145.83 DH 60 7.33 0.1 1 5.25 8.75

Reviously recordrd distribution in northern BC: Throughout porthan BC (Clarke 1981). Dlmaafon: Pisidiuni casertanzim wu a vay cornmon mUusc in ~rhemBC king found at 8 1 of 176 sites. It was fodin both the Paciiic and Mcdrainages, in di the major watashds, ecopvinces ad biogeoclimatic zones.

The range and mans of the environmental variables for the sites at which P. casertanum was collected are shown in Figure 2-14.

Figure 2-14a shows P. casertanum was collected at temperatuns >2S°C suggesting tht temperature may not be a Limiting factor in the distribution of this species in northem BC.

Dissolved Oxvnen: Figure 2-14b shows that P. casertumm was mWed in habitats of very low dissolved oxygen (e.g., 8% saturation). This suggests that P. casertanuni may be oxygen-iadepcndent and can tolnate iow oxygen environments so that the oxygen saturation of a habitat mynot be a limiting factor in the distribution of this species in northern BC.

Conducti~iw. . an d Calcium Concentration: Figure 2-14c shows that P. casertanum was found at the lowest levels of conâuctivity/calciiim concentration mdin this study. This suggests that the level of conductivity/caicium concentration may not be a limiting factor in the distribution of P. cumtanum in northem BC. nEI; Figure 2-14d shwn that P. casertamm was foimd to occur over a bmad range of pH including boih acidic and aikaline conditions, dom to a low level of pH = 5.25. Most of the otha Pisiditlm @es in this stuây appcar to pnfa for alt9lint conditions. This lowa tolwnce by P. cusertunum may aliow it to live in habitats mt accessible to nieny othr PIsidium spaia and may not be a fbctor grcatly restricting its distribution in northan BC,

The CCA results arc that the Pisidium species are not ttsponding signifidy to the envirorimental variables measured in this audy (p=û.225) with 3.m of the species p~esareaccauntcd for (Filpue 2-20). The plot shows P. ca

Clarke (1981) inditates that the rmge fa P. cusertanum is tbroughoui mrthan BC, which cownwith the findings of this study. This distniution gives no evidence of my bruners encounid during pst-glacial dispersion.

Clarke (1981) anci H-on (1%2) statc îbat P. caertrrnum is the mst cornmm species of

PisEdium and that it is found in di typa of perrnancnt and tcmporary wata habitats, which CO~~C\~TSwith the £îndings of this snidy. Pisidium cornpressun Prime, 1852 Ridgebeak peaclam

DRAINAGFJWATERSHED J'ACIFIC: Fnser: Fosa(3). Ntchako(5). Saiw(4); Skeenr: Bulldey (1), Sbna(2); Stikine: kt(1) MC'l'IC; LM:Dax (2); Pm#: ûmincca (1). Parsnip (2). Pcacc (a), Pine (1) ECOPROVINCEJECOREGION BordPlriPr :Pace River Basin (2), Southcm Albaa UpW(2) Centrai Interfor :Fraser Plateau (2) Corit & Mounîahs: Nass Basin( 1), Nass Rangcs(1) Northern Bord Mountrina: Bonai Mountaias and Phaus (l), Liard Basin (2) Figure A-50 - Collection sites for PLridiunt compteSmm. Subbdinterior: Fraser Basin (l3), Omiaeca BIOCEOCLIMATIC (BGC) ZONE Mountains (2), Central Canadian Roclty Mountains (4) Bord White and Black Spruce (10) Interior Cedar - Hemlock (2) Sub-Bord Spnice ( 18) Envirunmentai Information: Mersurement Count Me= StdEmr Minimum Muhum , TemPetantn (OC) 20 19.48 0.85 13.40 26.50

--- -- Rtviously recordcd dbtribution In nortbern BC: Throughout northun BC (Ciarkc 198 1). Discussion: Pisidium compressum w& a 00-11 moUusc in aorthem BC king found at 29 of 176 sites. It was fodin both the Pacinc ad Arctic drainages and in ail but the Taiga PlMs ccoprovince. It was ab- hnthe northeast of the mdy am The thrce BGC mes in wôich it was found have mean annual tcmpartims mging fbm -2.9 to 8.X with up to 7 months below OOC and up to 5 months above 100C. Altitude within thae BGC zones ranges hm 230 to 1500 m with mecin annual prcFipita5ion mging hm330 to 1200 mm.

The range and mnnr, of the enwonmmtal 1,*1a mawnd at the sites at which P. compresmm was collecteci are humin Fi- 2-14. Temperanut: Fi- 2-14a shows that P. compressum was collected in habitats whae the taopadnin was >2J°C suggcsting that hi@ temperature! rnay not be a Iuniting fator in the dishibution of this species in northcm BC.

Dissolveci Oxvm Figure 2-14b shows tbat P. compressum was not collected in habitats of extremely low dissolved oxygen. This suggests that P. compresmm may be an oxygendependent species, which rnay limits its distribution in noithem BC.

Conductivity and Calciuq: Figure 2-14c shows that P. cornpressuni was not collected hmthe habitat of the lowest conductivity/calcium measdin this study. It may be that the minimum level at which P. compressum was found (12.8 mdl), qresents the minimum tolerable level for this species. a:Figure 2-14d shows that uniilce many otha Pisidium species in this study, P. compwsum was collcaed hmhabitats of both acidic d alkaline conditions, ahhough more oftm in aikaiine conditions. It was not found in the habitats of lowest pH measured in this study indicated tbat it may be somcwhat intola~ntof acidic conditions. This suggests tbat P. compresmm may k somcwhat iixnitcd in its distribution in Dathan BC by the pH level to the habitat.

The CCA dtsare that the PrSidiurn @es arc not nsponding significantly to the environmental variables mdin this study QW.225) with 3.7?!! of the species prtsenct accounted for (Figurc 2-20). The plot of cnvironmcntal variables shows P. conipressum to occur ncar the ongin of hevzviablcs but is slightiy onsd to bigba than avaage discolvd oxygcn anci pH, which docs aot appear to be in sccordsire with the ccology of this spies as discussed above.

ClrrLe (1981) indicatcs that the range of P. compressrun incldes di of mrthem BC. Whilt P. compresmm was absent hmthe wnhacc of the study am, it was found cast of the Roc@ Moimîains near Fort St. John. This mge and CluLe's (1981) observation that P. compmsum occun throughout mrthm Albata adthe NWT an comhknt with th* nudy. This widapnd distn'bution @es no indication of any barriers amunterai âuring post-giacial dispersion.

Heriiagton (1962) and Clmke (1981) desak the habita! of P. compmsum as parnanent watn bodies, such as lakes, and in the slow mving paris of creelrr and rivers. These an the types of babitats in which P. compmsum was coilected dining tbis study. A'sidium conventus Clessin, 1877 Alpine peaclam SITES (6): NlO31,NlOS i,NLOS8,NlO81,N1102,N1104

PACIFK: Frircr: Nechako (l), Sm(1); Nass: Nass (1) UCmC:Lkd Desre (l), Fort Nelson (1). Liard (1)

CcnW Interior: Fraser Phteau (1) Coast & Mountains: Nass Basin (1) Northtrn Bord Mountain~:Liard Basin (2) SubBord Interior: FmBasin (1) Tdg8 Pbiiu: Hay River Lowlud (1) BIûGEoCLIMATIC ZONE ~tWlrrCiJc~mDPO#, Bonal White and Black Spnice (3) interior Cedar - Hernlock (1) Figure A-5 1 - Collection sites for Pisidium conventaa. Sub-Boreai Spnre (2)

Dissolved @ (% Saturation) 6 80.1 7 7.35 45.00 - 93.00 Conductivity @Siemens) 6 256.70 69.95 94.60 - 550.00 Calcium (mlf/litrc) 6 36.94 10.43 12.77 80.67 DH 6 8.12 0.09 7.90 8.50

Discussion: fisid*n ConventUr was an ummmm moiluoc of northem BC being found at sh of 176 sites. It was found in both the Pa&c snd Atctc drainages in five of the six nonhm ecoprovinces. The thrce BGC zones in which it was foui have mean annual tempanhircs ranging hm-2.9 to 8.X with up to 7 momths klow 0.c and up to 5 months above 10°C. Altitude within these BGC un*r ranges hm230 to 1300m with wctn annwl pmipitation mghgfiam 330 to 120 mm.

The range and means of the envirolll~l~~ltalvariables for the sites at which P. conventus was collected are shom in Figure 2-14.

: P. conventus is bwnlu a cold-watcr species usually ocamhg in decp wata (CluLe 1981). In this study, it was oftm only shells tbra wen coiiected thus, the nlstivdy high tcmpasturrs at which this species was collectai mi@ mt bc kveof the acaial conditions at whidi tbis species would k found (Figure 2-14a). Dissolvexi Oxv~gl;Figure 2-14b shows tbat P. conventus was collected ody hmhabitats of relatively hi@ dissolved oxygen. This suggests that P. conventus may be an oxygendependent species. However, as àiscussed above, as often only shells were collected, the environmental variables measured at the sites where P. conventus was collected may not be representative of the achial conditions at which this species would be fod. It may be expected that deep-water species would ohencornter hypoxic situations and thus, may be oxygen-independent.

Cooductivitv and Calcium Concentration: Figure 2-14c shows that P. conventus was not colîected hm the habitat of the lowest conductivity/calcium concentration maisund in this study. It may be that the minimum level at which P. conventus was found (12.8 mg) represents the minimum tolerabte level for this species.

& Figure 2-14d shows that P. conventus displays a very namw range of pH tolerance, king colleaed only in quite alkaline conditions. This may be a factor that affects the distribution of P, conventus in northern BC and that may separate it ecologically hmmany okPisidium species.

nie CCA dtsare thi the PrSidium spccies are not responding significantly to the environmental wiabla masurrd in this study (g.O.225) with 3.7% of the spcçies pcsaicc acwunted for (Figure 2-20). The plot shows P. conventus to correspond with higher than average pH. This seems to be m important envuOnmcntal variable that may separate P. conventta hm otha species of ibis gcnus.

P. comtentw is known hmmuch of Candi ad its mge includes al of &an BC (Clarke thU sady hm ams 1981). As almost all collections in wac muic shaüow ncar shore miring the . summci, it may k that P. conwntus is much more conmion tban indicatd by the findings of this study but was in decper, colder water. This widcspad distribution gives m indication of my barriers imposecl during post-glacial dispasioa

(Clarke 1981) stag that P. conw~uis unusuel, in tbrt it is a cold-watu species that lives primaily at considuable dcpths in hrge lakcs witbin the tmpmte parts of its range, ad at all depths Mthin abarctic and arctic regions. Clarke (197%) lists P. conventus as indicative of oligotmphic lakes. In thU shdy P. corn- was cdstcd âom lsLa and ponds, which ~ancwwith its kwwn ecology of bMg fouad at shallowa dcpth in the &arctic parts of its range. These habitats were mt aii oligotmphic and it may be tht the daignation of P. conventus as an indicrtor of oligotrophy may also only apply in thcsouthcrnpartofnS~.Inthismuty,ontsprcimenwr,slsocolîd~theslowmo~ua of a river. Identification of tbis one spccimen was pmblcmatic and codhation of this identification shouldkmadcbefmcxpînmpgtbtriirbibttypesoftbisspecia. Pisidhm faUux Sterki, 1896 River peaclam

SITES (4): Nlûûû, N1010, NO102, NO103

Bord plrini :Southcrn Alberta Uplands (1) SubBord Interior: Fraser Basin (3) BIOGEOCLIMATIC (BGC)ZONE Bonal White and Black Spruce (1) Sub-Boreal Spruce (3)

Figure A42 - Colleaion sites for PiSidium/oIIlm. Environmentai Infoimrtion: Mersurement Count Mean Std.Error Minimum Maximum TemperatUn (OC) 2 19.05 0.55 18.50 19.40 Dissolved @ (% Satiiration) 2. 76.50 10.50 66.00 87.00

Coductivity (pSianear) 2. 262.00 59.00-. 203 .W. 321.00 Caicium (mfltrc) 46.53. pH 2 7.63 0.38 7.25 8.00 Rcvioiuly mordcd dhtributiom hi northem BC: Not pnviously tccorded (Clarke 198 1) D~uuion: Pisiàiiunifillax was an uaeonm~nmllusc in northclll BC bdgfound at foin of 176 sites. It was foui in bth the Pacifïc and Arcâic drainages in dythe two sousheastan ~coptovinces. The two BGC zones in which it was foimd bave mcrn muai tempacmirrs ranging hm-2.9 to 5.0 OCwith up to 7 tnomths klow 0°C anà up to 5 month above 1K. Altitudes within these BGC un*, range hm230 to 1300 m and mean annual prceipitation mgcs hm330 to 990 mm.

The rans anci mrns ofthe enviromcd variables for the sites at which P. follm was dcctcd are shown m Figure 244.

TepDrnniUc: Figure 2-14 shows tbat P. follm was cdected only at reiatively low tmpmtms. Howevcr, the d smp1e site (~2)does not diow any ewlogical hypotbesis to k dram hmthis data. Dissoived ûxvpen: Figure 2-14b shows that P. fullm was coliected only at relatively hi@ levels of dissolwd oxygen. However, the dsample size (~2)does aot allow any ecological hypothesis to bc dram hmthis data.

Conéuctivitv and Calcium Concentration: Figure 2-14c shows thet P. fallax was collected only at nlatively high levels of conductivity/caicium concmhation. However, the small simple size (n=2) does not dowany ecologicai hypothesis to be dram hmthis data.

Figure 2-14 shows tbat P. folku was colhed only at aikaline pH. This is very simiiar to the hdings for many otha species of Pisidium. Howeva, the srnall sample size (n=2) does not aiiow uiy ecological hypothesis to k drawn hmthis data.

The CCA mulis are that the ?%sidiun opsies are not mponding significantly to the enviramental variabla measurai in this snidy (~4.225)with 3.7% of the speçies presence accounted for (Figure 2-20). The plot shows P. filllox to be assoeiated Mth higha than average conductivity. Whiie this concurs with the plots in Figure 2-14c, the small ample size does not aliow forniwon of a uMmodal rcspoase to any variable and its occ-e hae is of limitai ecological inteiprdability.

The distribution of P. fillm has not oi previously dedto include norchcm BC (Clarke 1981). Tbis spccies was not fodoh in thU study and was oniy found in th souîheast of the study ma, which extends its range fûrthcr west than pmiously describai, and dso into the Pacifie drainage. Identifïmtion ofthe specmvPs coktcd in this study wuprobldc in tbat whik the A2 antoior lateral tooth was vay heavy, it did not display the twisthg that cWaizes-this specics. Howcver, the spimas wac idestifid as P. @lux as al1 otha chactcrMcs wae closest to those describal by Haington (1962) as bcing distinctive to that spia. .

Ciarke (198 1) states that P. filla is mcommon and üves in rivers, sûcams, d exposcd habitats in Mes. Hd8ton (1962) âcscrii P.fohu as ippesnog to üIte moving wsta adha* a &strate pnfaence of sdor gravel. in this study, the spccimens idgitified as P. @lux wac coilcdd hmWes and ponds having muddy bottoms. Contirmation of the identification of the spechas coîîected in this study this should be madc before txppidiag the habitat types of ihis spccies.. Pïsidium ferrugineunt Prime, 1852 Rusty peaclam SITES (23): N1007,N1014,N1018,N1033,N1039,N1046,N1048, N1oS9~1052,N10s4~10S6~1059,Ni064~1069~ N107S,N1078,N1098,N11ûû,N1111,NO lO7,NOllS, NO &îO,CNlOo6

PACIFIC; Coastd: North Coast (1); Fnrer: Fmcr (1), Nechako (3);Skeem :Bulldey (1) stikine: Stüane (2) ARCTIC: Liard: Dacc(3). Fan Nebon(1)Liard (S),Toad (1); Mackemit: Hay (1); Perce: Wkathw (2), Peace (2)

Bonrl PWnr: Ptace River Basin (1), Souîhem AlhUplandP (1) Centml Interior: Frasct fhueau (2) Cmit & MouMahs: No- Coastal MU.(1) Fi- A-53 - Collection sites for Pisidiumjemgineum. Nortbern Bord Moumtrinr: Northcni Canadian Rocb Mouabh (l), Bord Moutains and PtatrauP BIOCEOCLIMATIC ZONE (3), Liud Basin (6) Bord White and Black Spruce (14) SuMord Interior: Sicecm Mouîains (1 ), coastal western Hdock(1) Centrai Cliaadian Rocb Moimtaias (I), ûmincca Engelmann Spuce - Subalpine Fir (1) MouataiPs (l), Fraser Basin (3) Interior Cab- Hemlock (1) TdpPb: Hay Riva LowM (2) SuMoreai Spruce (6) Environmental Information:

Dissolvd 4(% Saniration) 19 69.66 4.57 8.00 99.00 Conâuctiviîy (psimens) 19 268.18. 37.00 73.60 735.00 Calcium (mgllitre) 19 38.65 5.52 9.64 108.25 pH 19 7.53 0.15 6.50 8.90 Reviody recordcd diatribution hi northtm BC: Throughout northem BC (Clarke 198 1). Discuision: Rsidium fenuginnown was a comamn moiiusc m norihem BC kgfond at 23 of 176 sites. It was fouPd in both the Paciiic and Mcdrainages in 1of the six ecoprovin~~~~It was not collectd within the Spluct-Wrllow-Birch BGC zone. The five BûC zoms in which it was collectai bave mean mual tcmpcratiaes mging hm-2.9 to 10.S with up to 7 monîhs below O.C ancl up to 6 months above 10°C. Altitudes within thae BGC zones ranges hmO to 1700 m with meim annual prscipitation nogiog hm330 to 4400 mm.

The range admeans of the eavitommtaî variables for the sites at which P. fimginetlm was Temb~ramFigure 244a shows that P. femgineum was fouad at ternperatures >2S°Csuggesting that temperature may not k a limiting faor in the distribution of this specia norihem BC.

Dissolved On- Figure 244b shows that P. /emgineum was collccted in habitats of vay low dissolvd oxygai (8% saturation). This suggats that P./emgïneum may be oxygcn-independent, able to tolerate low oxygen environmeniS. Thus, the level of dissolved oxygen of a habitat may not be a ümiting factor in the distribution of P. femgineum in inorthcm BC.

Conductivitv and Calcium Conccattation: Figure 2-14c shows that P. femgineum was not coMed hm the habitat of the lowest conductivity/calcium concentration memureai in this study. It may be that the minimum level at which P. ferruginam was fouad (9.6 m@) represrnts the minimum tolerable Iml for this species. a Figure 2-Md shows that unWre many der Pisidiuni species, P. femrgineum was coilected hm habitats of both acidic anâ alkaline conditions, dllthougb mon oftai in aikaline conditiom. It was not found in the habitats of lowest pH mdin this study suggcstiog that it may k somewbat intolcmt of acidic oonditions. This suggcsts that P. femgineum may be somcwhat limited in its disüibuîion by the pH level of th habitat.

The CCA dts are that the Bscdium species arc not rcsponding significantly to the aiMn,nmentai variables mcaswaî in îhis study (p=û.225) with 3.7% of the picspmencc accounted for (Figure 2-20). The plot shows tbat P. fmgineum comqonds to no parîinilar vaxiable and occurs vay nesr tht origin.

Clarke (198 1) indicaics îhat the dictniution of P. femgheum includes aü of norihan BC, wbich concm with the fïndings of this dy. This widapreid distn'buton gives no indication of any basrias cncountered during pst-glacial disperd.

Clarke (1981) states that P. fmgineum is fodin lakcs, ponds, rivm and strcanis which arc the habitat types in which P. fimghem was foui in this shdy. Pisidium idahoense E.W. Roper, 1890 Giant northem peaclam SITES (17): NlOO9,NlO 1 1~1056,N1062~1067,N1068,N1033, NlO8O,N1082,N1092,N1102,N1104,CN1~ CN1008,CN1010,MNf û@t,MNlOO6

DRAINAGWATERSHED PACIFIC: Fnser: Fmm(l),Ncchako (l),Saiut (1); NIIS: Meziaâin (1); Skeem: Bulkley (1), Sloano (1); Stikint: Iskut (1), StüQne (1) ARCTIC: Liud: Kechika( l),Dctw(3),Liard(1); Pw:Finlay (l),Omiocca (l),Peace (l),Pine (1) ECOPROVINCE/ECOREGION Bort81 WS:Pace River Basin (1) Cenhrl Interior: Fraser Plateau (2) Cwd & MOUII~~S:Nass Basin (2) Nortbern Bord Mountains: Noh Canaàjan Rocky Mountains (l), Liard Basin (2), -- -- - Bord Moutains and Piateaus (5) Figure A44 - CoUcction sites for Pisidium idahoe~~~e.Su&BOred httrior :Centrai Canadian Rocky BIOGEOCLIMATIC ZONE MU. (11, Omiaeca Mts. (l), Frascr Basin (2) BodWhite and Black Spruce (10) Interior Cadar - Hemlock (2) Spnice - Willow - Bir& (1) Sub-Bord Spnice (4)

Reviou8ly recordcd dbtribubkn in northera BC: Tbrougbout mrthcm BC (Clarke 1981) Discussion: Pisidium i&hwnse was a eoDnmon moiiusc in aoitlpan BC king fouad at 17 of 176 sites. It was found in both the Pacinc and Arctic drainages in aii but the Taiga Plpias ecoprovince and so was absent hm the no- of the study ama. The four BGC mnes in which it was foui have mean muai tmpatms rangîng hm-3.0 to 8.Xwith up to 7 moiitlis below 0.c and up to 5 maths above 1o.C. Altinides within these BûC zones mges from 230 to 15ûû m with meaa annuai praipitation ranghg hm330 to 1200 mm.

The range and means of the environmentai variables for the sites at which P. idahoerne was coUccted an shom in Figure 2-14. T- T- Figure 2-14a shows that P. i&hwnse was oniy collectai in ôabitats of nlatively low temperature. P. icibhoerue is hownas a ml-water species (Hedgton 1962), most fiesuently found in cold arctic and mountain Mes (Clarke 1981). This suggests that the distribution of P. ihhoense in northem BC may be somewhat btedin its distribution by intolerance for high wata tanpaptine.

Dissolved Figure 2-14b shows 16at P. ihhoenre was mt collsted in habitats of extremely low dissolved oxygen. This suggcsts that P. idahoetue may be an oxygendepcndent spccies. This hypoxia intolerance may be a factor that lirnits the distribution of P. idcihoense in northern BC.

Cm: Figure 2-14c shows that P. i&hoeme was not collected fmm the habitat of the lowest condu*ivity/caicium measured in this study. II may be tbat the minimum level at which P. idahoense was found (1 2.8 mfl) tcptesents the minimum tolaeble level for this species. ptI; Figure 2-14d shows that P. idahoense was collecteci oniy hmhabitats of ncutral to alhiline pH suggesting tbat it may be intolerant of Mdic conditions. This mny be a factor tht limits the distribution of this specics in northm BC.

The CCA Wts are tbat the fiidlum specics are not mponding significantly to the enviradvariables messurcd in this study (p4.225) with 3.7% of tht spacies prrscnce accounted for (Figure 2-20). The plot shows P. idclhoense to appmr in an area whac it is not associateci with a si@ variable.

Ciarke (1981) indicates that the distribtiticm of P. idzheirpe incluàes aii of mrthcm BC. We P. idphoellse was absent hmcollections dein the br northcmt of the study ana, the Wbution mappsd by CMe includes northem Albuta and the North West Tenitones. Thus the distriion found in tbis study pmbably concm with that of Ciarkc. 'Ihis widespmà distribution gives no evidaiw of any ôarxiexs imposeâ during post-dacial dispasion.

Clarke (1981) descn'bes P. idahoeme as most fkpcntly hgfound in laites, and tht it is indicative of rntsotropbic lakes (Clarke 1979b). In this study, it was most commody fomd in lakes, but 0thttaae Mes tendai to k oiigotrophic. P. idohwme was rlso coUeacd fhm the slow moving ueris of rivas ad strtarns. Pisidium insigne Gabb, 1868 Tiny peaclam

SITES (1): N1076 DRAINAGENATERSHED WIFIC: Nam: Bcil Irving ECOPROVINCEIECOREGION Sub-Bord Interior: SWMountains BIûGEûCLIMATIC (BGC)ZONE interior Cedar - Hemlock

Figurc A45 - Collection sites for Pisidium imigne. Environmental Information: , Memonment Count Observed Tcmberanire ("cl 1 22.60

Calcium (mmtre) 11 1 1.98 nH 1 1 7.05 Prtviowsly mordd àistributbn in northern BC: Not pmriously recordai (Ciarke 1981). Dlscuuion: Pisidium imigne was an uncornmon mollusc in northan BC bang fouod at one of 176 sites. It was fodody in the Pacinc drainage in the Sub-Bod Interior ecoprovince. The BKzone in which it was fodhas a mcsn annual taiipanm of 2.0 to 8.X with up to 5 months klow 0°C and up to 5 months above 1O.C. The altitude ranges fom 100 to 1ûûû m with annuai praipitation ranghg hm500 to 1200 mm.

P. insigne was coliected hm only one ecological site. Thc maure of the aiviramental variables a the site whae P. insigne was wliected are shown on Fi- 2-14 as a dot.

Variables: Figure 2-14 shows that the tempcfat~~~dissolved oxygen, conàuctivityIdcium concentration, adpH mrsund at the one site for P. insigne are within the raqe of rnmmmmts defor most othcr @es within this gcnus. The meamemcnts made with tbis single coiiection do not aiiow the formation of any hypotheses as to the ecology of this species. 219 The CCA dtsan that the Pisidium species arr not responding sisnificantly to the environmental variables measdin this study @50.225) with 3.7% of the spccies pmence accounted for (Figure 2-20). The plot shows P. insigne is not associateci with a single variable.

Clarke (198 1) indicates that P. insigne is hown in Canada only hmfour sites, none of which are in noithern BC. This stuây increases the range for this uncommon species. This one site gives no evidence of any pattem of pst-glacial dispasion.

Tbis species is very small with the aduhs las than 2 mm long and aimost nothhg is hown about its biology (Clarke 198 1). Clarke (198 1) and Harington (1 962) state that P. insigne is found principaîly in slow moving creeks and spring creeks. In this study, P. insigne was fouad in a laice. Pisidium lilljborgi Clessin, 1886 Lilljeborg peaclam SITES (15): NlOOl~lOO2,NlW~100S~1006, N1008,N1011,N1026,N1034,N1052,N1054,N1060. Nl063,CN1004,Miü1003

PACïFïC: Fraser: Nechako (1);Stikine: Ishn (1) ARCTIC: Wud: Derre (3), Fort NeLon (1). Lisid (2); Perce: Paftnip ( 1), Peact (S), Pint (1) ECOPROmCEYECOREGION Bond Plains :Centrai Alberta UpW(1) Northern BondMomtrins: Boreal Mountains and Plattaus (3), Liard Basin (3) Siibhreai Interior: Omineca Mountains (l), Cenaai Cansdian ROC^ Mts. (2), Fraser Basin (4) TdgPb: Hay Riva towl~(1) BIOGEOCLIMATIC (Bcc) ZONE Bord White and Black Spnrce (8) - - Spnice - Wiiiow - Birch (1) Figure A46 - Collection sites for Pisidium lilfiebargi*. Sub-Bord Spnice (6) Environmental laforilution: Memurement Count Mern Std,Error Minimum Mnrimum Temperotun("c) 13 20.68 0.95 15.70 27.20 Dissolved Q (% Saturation) 13 75.00. 4.40 46.00 98.00 Conducîivity (psiemens) 13 22 1 .52 28.84 76.90 434.00 Calcium (mfltre) 13 3 1.69 4.30 10.13 63.37 pH 13 7.70 0.17 6.95 8.90 Revioady recordcd &tribation hi nortbern BC: Thughout northan BC (Clarke 1981). Discasrion: Pisidium liI&eûutgi was a cmmoiiusc of mrthm BC bchg found at 15 of 176 sites. It was foMd in both the Prific and Mcdrainages in four of the six ccopmvinces mt being colîectd from the southwest of the study area. Th tbrte BGC ames in which it was fodhaw man umuai tcmpashirrs ranging hm-3.0 to 5.W with up to 7 montbs klow WC rad up to 5 mths above lOOC anâ with mean annuai piscipitation ranging hm330 to 990 mm.

The mge and means of the environmental variables for the sites at wbich P. lil&elwgi was coîiccted are show in Figure 2-14.

Tanmaturc: Figure 244a shows P. was coiiected at tappaahnes >2S°C sugptbg that tempartim may not be a limiting factor in the dktri'bution of P. lilljebqi m mrtbcm BC. DisMIved Ox~petl:Figure 2-14b shows tbat P. lilljebogi was not coîlected in habitats of extrcmely low dissolval oxygen. This suggests ihat P. lilbeborgi may be an oxygendependent specis. This hypoxia intolerance may be a factor that limits the distribution of P. lill/e6urgrrgrin northem BC. . . Conductrvitv and Calc uni Concentratiog: Figure 2-14c shows that P. lilljeborgi was not collected hm the habitat of the lowest conductivity/dcim concentration measured in this study. It may be that the minimum level at which P. lilijeborgi was found (10.1 md) represents the minimum tolerable level for this species.

a Figure 2-LU shows that P. lil&eborgi was coliected only hmhabitats of neutrai to alLaline pH. It appeam that P. lilfieborgi may be intolaaat of acidic conditions and that this may be a factor that limits the distribution of this species in northem BC.

The CCA nsults are that the Pitidium species are not mponding significantly to the envitomenta1 variables mdin this stuûy (p=û225) with 3.7% of the apecies presence accounted for (Figure 2-20). The plot shows P. lif&eborgicomlateâ to no particular mvitonmental variable.

Ciarkc (1981) indicates that P. lil@eborgi*is fouad throughout nortbern BC which gencrally concm with the firiciings of this study. Although P. lil@ebar@was not collectcd in the wuihwest of the stuây am,it has kai co11ectd hmcd locations elsewhere in BC (Lee ancl Ackaman 1998b). This widapnsd distribution gives no evidcnce of any barriers imposeci durhg pst-glacial distributon

Clarke (1981) anû Harington (1962) ddkP. li1&eborgteas in ail permanent wata habitats with a prrferc~ctfor lakes. In this study it was aiso fodprimuiy in Lelres with one coilcction hwn the slow moving arca of a crcck. Pisidium milium Held, 1836 Quadrangular pillclam SITES (20): N1007,N1011,N1018,N1026,N1034,N1043,N1048, N1û49,NlOS2,N1059,N1066,N1068,N1069,N1072, N1074,N1098~1111,NOlOJ,!W109,NO113 DRAINAGWATERSEED PACIFIC: Fraser: Fraser (1), Nechako (1). Sm (1); Skrtm: Bulklcy (1); Stiliae: Stikinc (3) ARCTIC: Lhrd: Dtase (3), Fort Nelson (2), Liard (3); kce: Kiskatinaw (1), Ptace (3), Pint (1) ECOPROVINCE/ECOREGION Boml plains :Central Alberta Uplaads (l), Pace Rinr Basin (1) Central Interior: Ftaser Plateau (1) Noitbern BordMountrins: Liard Basin (4), SubBornl Interior: Omiaeca Mouutains (l), CdCaiiftdinn Rocky MIS. (2), Fraser Basin (3) Tdg8 Pb:Hay River Lowld (2) Figure A-57 - Collection sites for PLsidium milium. BIOGEOCLIMATIC (BGC) ZONE Borcal White and Black Spnia (14) Engelmann Spruce - Subalpine Fu (1) Sub-Bord Spwe (5) Meuurcment Count Merin StdEmr Miaimum Maximum Tempcfam (OC) 17 18.1 1 0.98 12.10 27.20 DissoIved (% Saturaiion) 17, 72.09 4.84 8 .O0 98.00 Conductivity (pSicmens) 17 266.00 26.73 66.40 475.00 Calcium (matre) 17 38.33 3.99 8.56 69.49 . pH 17 7.46 0.16 6.50 8.90

Discussion: Phidiun miiium was a common mollusc in mrthem BC foinad at 20 of 176 sites. It was found in southwest of the stuây arca. Th thne BGC zona in which it was found bave mean annual tanpasMcs ranghg hm-2.R to S.OOC with up to 7 monshs klow 0.c and up to 5 mnth above 10°C. Annual prccjpitation in these zones range hm330 to 2îûû mm.

The range and mans of the é~~viromdvariables for the sites at which P. milium wos

>2J"C SU- thai bigh tempcrature may not k a iimiting factor in the distribution of this specits in northcrn BC. 223 Dissolveci OXY~Figure 2-14b shows that P. milium was collectecl in habitats of veiy low dissolvai oxygen (e.g.. 8% saturation). This suggests that P. milium may be oxygen-independent and can tolerate hypoxic conditions. T'us,the lm1 of âissolved oxygen of a habitat may not be a f~orthat limits the distribution of P. milium in northern BC.

Conduçtivity and Calcium Concentration: Figure 2-14c shows that P. milium was not collected hmthe habitat of the lowest coaductivitycaicium measureû in this study. it may be that the minimum level at which P. milium was founà (7.5 mgll) represents the minimum tolerable level for this spccies.

& Figure 2-14d shows that &e many 0thPIridium species, P. milium was collected hmhabitats of both acidic and alkaline conditions, aithough more ohin alkaline conditions. It was not found in the habitats of lowest pH measureà in this study, indicated that it may be somewhat intolerant of acidic conditions. This suggests tbat the pH level to the habitat may limit the distribution of P. milium in northem BC.

The CCA dtsare that the Pisidium species are not responding significantiy to the environmental variables mainacd in this study @=0225) with 3.7% of the species prescncc accounted for (Figure 2-20). The plot shows that P. milim does net comspond to a single variable, as it apPcsrs on the plot near the ongin.

Clarke (1981) indiCates that the distn'bution of P. milium does not incluâe northem BC. P. milim was fouid thnwighout noithem BC in this shidy inaesPing its range much fbher west in genexal. and much fiirthn north in BC. This widapmd distn'bution givcs no indication of any barriers cncountatd duiing pst-giaciai dispersion.

Cluke (1981) ddksP. mimi2iumas uncormnn~~d living in ks,ponds, adslow-moving streams. h Uljs study, P. milium wa, pot uncommon, but was found living in the type of habitats as daniad by cw. Pisidiium nitidum Jenyns, 1832 Shiny peaclarn SITES (13): N1003,N1005,NlOl l,N1014,N1018,N1034,N1055, N lOS8,NlO59,NO1 10,NO 120,CN1000,CN1014 DRAINAGEIWATERSHED PACIFIC: Friser: Ntchako (l), Sniart (1) ARCTIC: Liard: Dase (2), Fort Nelson (1). Liard ( 1);Ptrce: Kiskatinaw(2), Pace (4), Pinc (1)

BO^ Plrias: Peacc River Basin (1). Souhem Alhuplands (2) Centrd hterfor :Fraser Plattau (1) Noflhern Bord Mountiina: Liard Basin (3) Sub-Bord Interior: CdCanadian ROC^ Mountains ( l), Fraser Basin (4) Taiga Phini: Hay River towland (1) BIûGEûCLIMATIC (BGC) Ulm Bord White and Black Spruce (8) Figm A48 - Collection sites for Pisidium nitidum. Sub-Boreai Spnre (5) Enviroamentai Information: Mersurement Icount I~ean

Dissolvcd 9(% Sahiration) 1 9 70.56 2.681 59.00 81.00 Conductivity @Siemens) 9 239.37. 23.62 146.80 336.0 Caicium (rnfltre) 1 9 34.35 3.52 20.55 48 .76 pH 9 7.80 0.13 7.05 8.30 Reviou~iyrre~rdcd dbtribution in nortbem BC: Eastern arca only (Clarke 198 1). DisCuiaion: fisidium niamwao a commou moîiusc in norihan BC king fodat 13 of 176 sites. It was found in bath the Pacinc anà Arctic drainages in d but the Coast and Mountains ecopvince in the wuthwcst of the shdy arca. 'Ihc two BGC zones in which it was fdhave mean annuai tempmtms raaging hm-2.9 ta 5.0 OC with up to 7 montbs Wow OOC and up to 5 months abve 1OOC and with

The range and mcsns of the environmentai variables for the sita at which P. nitidwn was coliectd arc shown in Fi- 2- 14.

TBgpcrahuc: Figure 2-14a shows that P. nitidirm was collectai si tcmperatum >25OC su@g hi@ tempmtm may not bc a limitinq factor in the distriikdion of this spe*es in northern BC. Dissoived Figure 2-14b shows that P. nitidum was collected in habitats of reiatively hi& dissolved oxygen. This suggests that P. nitichrm may be an oxygendependent species. This hypoxia htolerance may be a factor that limits the distribution of P. nitimun in nonhem BC.

Coaductivint and Calcium Concentration: Figure 2-14c shows that P. nitihm was not collected hmthe habitat of the lowest conductivity/calcium concentration mawred in this study. lt may be that the minimum level at which P. niridum was fond (18.3 mN)represents the minimum tolerabie level for this species.

Figure 2-14 shows that P. nitidtrm was collected only from habitats of neutmi to aikaline pH. This suggests that P. nitidum may be intolerant of acidic conditions and that this mey be a f~ that limits the distribution of this species in northem BC.

The CCA resuits are tbat the Piri& species are not responding significantly to the environmental variables mdin this study (p4.225) with 3.7% of the spaies prescnce accuunteci for (Figure 2-20). The plot shows P. nitidum to correspond to no particular wiable.

Clarke (1981) indicatm that the range of P. nitidrrm includes the eatern area of northem BC. Most of the coilections made of P. nitidum in this study coirur witb thir am,however, thoc wae two collections dein tbe central northefll region of the study ana which extends thc range fûrthet wcst th that indicated by Clarke.

Ciarke (1981) states that states tbat P. nitidum üves in aiî lrinds of paeMial wata habitats. In this study it was collccted from Iakes, ponds and streams. Pisidium punctatum * Sterki, 1895 Pedorated peaclam

SITES (1): N1030 DRAINAGEIWATERSHED MCTIC: Liard: Fort Nelson ECOPROVINCE/ECOREGION T8iga Pb:Hay River Luwland BIOGEOCLIMATIC (BGC) ZONE Boteal White and Black Spruce

Figure A49 - Coiiection sites for hidium punctutum.

Dissolvd 02 (% Saturation) 1 56.00 - 56.00 56.00 Conductivity hSicmcns) 1 313.00 - 3 13.0 313.00 Calcium (mfltrc) 1 45.33 .. 45.33 45.33 pH 1 7.05 O 7.05, 7.05

~~OUS~Ym~~rdeddhbibudon h northcrn BC: Not previously mordai (Clarke 198 1). Discuraion: Puidium punctutum was an uncormnnn mohsc in nonhan BC being foui at ont of 176 sites. It was found only in th Arctic binage in the Tain Plains dcop~ovincc.The BGC zone in which it was fouid has mean annuai tempcrshin of -2.9 to 2.R with up to 7 months klow O.C anci up to 4 month above 1O.C with annuai precipitation of 330 to 570 mm.

P. punctatum was coiicacd ody at .one axlogicai site. 'fhe environmental variables at the one site whae P. punctutzîm was coiîected arc show in Figure 2-14 by a dot.

V-: V-: nie tappnshirr, dissolvd oxygcn ad conductiyity, and pH mdat this one site wcre within the range of mrrsiaemans made fa m~stotha specics within thîs gaius. The succokction doa not dow the formation of any hypothcscs as to the ecology of this spceies in regsrds to these four variables. The CCA results are that the Pisidium species are not respondiag significany to the enw01~~atalvariables meas4 in this study @-0.225) with 3.7% of the species pmare accounted for (Figure 2-20). The plot shows P. puncrotum to correspond to no particular variable.

Clarke (198 1) indicetes the distribution of P. punctaturn docs not include northem BC and that it occm oniy in scattered localities in southern Canada. The identification of tbis species was probletnatic as thae were only two very mal1 delicate specimem but the features scaned to indicate that P. punctatirm WBS the closest fit for identification. The range distribution for this species shodd not be changed until this identification is confûmed.

Clarke (198 1) describes that habitat of P. punetam as Wes aad slow-moving portious of river and stream. In this shidy, the opecimens identified as P. punctatum were collected hma flooded walaud. The habitat types described for this species should not be chenged untiî the identification of the specimens coiiected in this study are confirmed.

*Note: Herrington (1%2) nfas to tbis specics as P. punchimrn but later oomcts this idemification (Herrington 1965). A'sidium rotundalim * Prime, 1852 Fat peaclam

ARCTIC: Liard: KccW ECOPROVINCElECOREGION Northern Bord Mountiias: ona al Mountains and Platcaus BIûGEOCLiMATIC (BGC) ZONE Bonal White ad Black Sprue

Previoudy recordcd cbtributlon in northern BC: Not prcviously recorded (Clarke 198 1). D&ussian: Clarke (1981) does not includc northcm BC in the diskiiution of Pisidium mtundrrzum even though he mde this ooliection in Dpll Lake in 1972. As he chose not to hcludc tbis in his information, and as P. mtundptirm was tmt coiiccted clscwhere in northan BC during this stuây, tbae may k some question as to the identification of this coiiection. lt is included hac only to provide a synoptic fccord of aii coiiactions hmnorthen BC.

'Note: HcrNlgton (1962) nfas to this @es as P. obtusale; HCmngton (1965) mises this to P. ventrkomm, fom mwnrdatirm; Cîarke (1973b) anâ Biÿch (1975a) aiso uses P. vennicanm, forxn mttrndatum; Clarke (1981) and Turgcon et al. (1998) used P. ~)nrndahrmwhieh is the aomcttclatum foiiowed in this study. Pisidium vadabile Prime, 1852

PACiFIC; Coirtil: North Coast (1); Friser: Fraser (3), Nechako (4), Stuart (2);Niu: Bell-Irving (l),Mcziadin (l), Nass (1);Skeena: Bulkley (l), Lakelse (1); Stlldnc: Scikk (4) ARCTIC: Limk Kechika(l),Dcasc (5)Jt Nehn (S),Liard (9);Perce: Beatton (2), Kiskatinaw ( 1), Parsnip (l), Peacc (3), Pinc (l), Smky (1)

BordPhhs :Central Alberta UplaDds (l), Muskwa Pheau (I), Pcace River Basin (2), Southcm Alberta Figure A41 - Collection sites for Pisidium variabile. UP~(3) Centrd Interior: Fraser Plateau (3) BIOGEOCLIMATlC (BqZONE Coast & Mountiini: Coastai Gap(2),Naris Basin (2) Bord White ad Black Spruce (30) Northem Bord Mountrinr: Liard Basin (lO), CdWestern Hcmlock (2) Bonal Momtsins and Plntraii. (8) Interior Ceûar - Hdock (4) SubBore8i Interior :Sh MountriPs (2), SubBod Spnw (1 2) omineca Mouamina (l), Central Caaidian Roc& Mountains (l), Fraser BasM (7) Tdc Pbh: Hay Riva Inwlruad (41, Nonhem ,Envin,nmentr) Informrtion: -UP~ (1) Memurement Count Mem StdEmr Minimum Tanperature (DC) 36 18.49 0.67 8.70 Dissolvcd 4 (% Saturation) 36 7 1.83 2.64 . 41.00 Conductivity (psianais) 36 224.12 20.36 19.70 Calcium (mR/iitrc) 36 32.08 3.04 1.60 pH 36- 7.53 0.15 5.15 Previotlsly reconkd distribution fa nortbern BC: Tbroughout northcm BC (Clarke 198 1). Dircussion: Pisidium variobiie was a colllll~nmoliuoc in northcm BC being fouPd at 48 of 176 sites. It was fodboth the Pacifîc adArctic drainages ancl in aU of the ccopiovincés. The four BGC zones in which it was foui have man annuai tmpaatms ranging hm-2.9 to 10.SOC with up to 7 months below WC d up to 6 months above lOOC and with annual precipitatim ranghg hm330 to 4400 mm.

collectecl are shown in Figure 2- 14. T~~:Figure 2-14a shows P. vanabile was oollected at tanpaahucs >2S°C suggesting that high temperature may not be a limiting factor in the distribution of P. vmiabile in-northemBC.

Dissolved OxmFigure 2-14b shows that P. variabile was not collecteâ in habitats of extremely low dissoived oxygen. This suggests thpt P. variabile may be an oxygen-dependent species. This hypoxia intolerance may be a factor that limits the distribution of P. vanabile in northern BC.

Conductivity and Calcium: Figure 2-14c shows that P. vanabile was found at the lowest levels of conductivityIcalciummeasured in this study. This suggests that the level ofconductiviitycalciummay not be a timiting factor in the distribution of P. vuriobile in northern BC. a Figure 2-14d shows that P. variobile was found to occur over a bdrange of pH including both acidic and aikaiine conditions and was coliected at the lowest pH measwed for this family. This suggests that pH may not be a factor that vtlylimits the distribution of P. vatfabilein northern BC.

The CCA mults are thpt the Pipidium species are not responduig significantly to the environmental variables measUrcd in this study (p4.225) with 3.7% of the ~peciespnseace accounted for (Figure 2-20). The plot shows P. vanbbile to mur very near the origin and so is comlatd to no particular variable.

Clarke (1981) indiCates that the range of P. voriobile is thmughout noiihan BC, which connirs with the findiop of this study. This widcspcad distribution gives no indication of any barrias mcouutcrtd diamg pwi-glacial dispersion.

Clarke (1981) describes P. variabile as occwring in aU natural percPnisl water habitats. This concm with the hdings of this stuây whac P. vcricrbile was coNected hm lakes, poads Pad slow- moving arcas in creela, but it was dm coIIactcd once hma highway ditch that hsd a few pack of water. Rsidium ventricosuni (Prime, 1851) Globular beaclam

PACIFIC: Coidil: North Coast (1); FM: Frascr ( 1), Nechako ( l), Stuart (1);Skeem: Babinc (2) Sdldnt: Stikinc (3); Yukon: Atiin (1) ARCTIC; Liud: Dnse (1). Fort Nelson (5). Liard (3); bct:Beatton (1). H-y (1 ), Kistah'nnw ( 1 ), Pace (2). Pint (1)

Bodhhs: Muskwa Pb( l), Pace River Basin (l), Central AbtaUpW (2), Soutbmi AlbUplands (2) Corit & MoPntriar: Coastai Gap (1) Figun A-62 - Collection sites for Pisidium ventricusum. Northtrn Bord MOU- Liard Basin (3), Bonal Mountains and PIatau~(4) BIOCEOCLIMATIC (BGC) UlNE SubBonrl Interior :Slreena Mountains (l), BodWhite and Black Spruce (1 8) Cenaai Canadian Roc6 Mts. (l), Fraacr Basin (4) Coastal Western Hemlock (1) Tdg8 Pkiar: Hay River Lnwlrad (5) Engeimann Spruce - Subalpine Fu (1) Interior Cadar - Uemlock (1) Sub-Bord Sprucc (4)

Temperanire ("C) 23 20.07 0.85 10.40 27 20 Dissolvd 02 (% Saturation) 23. 65.72 3.84 19.00 87.00 Conâuctivity (psianens) 23 209.20 27.36 19.70. 475.00 Calcium (mfltre) 23. 29.86 4.08 1.60 69.49 1 DH 1 231 7.161 0.191 5.251 8.501 Previouaiy recordcd ~tiibubionin northern BC: Not pmiously recordad (Chice 1981). Discussion: Pisidium venfncomm was a conmion moiiusc in northem BC kmg fodat 25 of 176 sites It was found in both the Pacifie ciad Arctic drainages in ail but the CdInterior ecoprovince. The five BGC zones in which it was fouad haw mean annuai tanparnnes mghg f&n -2.9 to lOJT with up to 7 months klow OY: and up ta 6 maths above 10°C and wah annual precipitation nnging nOm 330 to 4400 mm.

Thc range anci meeiur of the enviromnad VlViZibIcs for the sita at which P. venmcmm was coliected are shown in Fiigiire 2-14. Ta~~~lcrturr:Figure 2-14a shows P. vuriabile was collected at tempera- >2S°C suggesthg that high temperature may not k a limiting factor in the distribution of P. vanubile innorthem BC.

Dissolved Omrpm: Figure 2-14b shows tbat P. venîricosum was collceted in habitats of low dissolved oxygen (1PA saturation). This suggests that P. vennicBsum may be oxygen-aidependent and so may tolaate Iow oxygen enviroments. Thus, the level of dissolved oxygen of a habitat may not be a limiting factor in the distribution of P. ventricornm in northem BC.

Conductivitv and Calcium Concentration: Figure 2-14c shows that P. ventncomm was found at the lowest levels of conductiVity/caiciium concentration mdin this study. This suggests tbat the level of conductivity/caicium msy not be a limiting factor in the distribution of P. ventncomm in nonhan BC. gj& Figure 2-14d shows tbat P. ve~cosumwas foui to occw over a broad range of pH including both acidic and alknlinc conâitions, and was coliected at close to the lowest pH meiisrmd for collections for this fhly. This suggests that pH may not be a limiting factor in the distriution of P. variabile in northem BC.

The CCA mults are that the Pisidiun specics an not rcsponding signüïcantly to the mMro~talvariabIes mdin this stuly Q~û.225)wiîb 3.7% of the species presence accoupted for Figure 2-20). The plot shows P. venticomm to occur vay near the origin and so it is not associated with a single variable.

Clarke (1981) indicates tbst the range of P. ventrrcusum does not include norihem BC. lbis is a very diff~i~~lfdistnôution than that fond in this stuây, whac P. ventricartrm was fouad throughout the stuây an* This widesprrd distriiiution @ves no indication of my barrias cncountd during pst- glacllldispssal.

CIuLc (1981) states tht P. ventncmm lins in paamial wata lelres, ponds, rivas and strrrmis of ail &es. In this study P. ventricosum was fouid in lakes anci ponds, but neva in flowing wata. A'sidium sp.

SITES (1): NI064 DRAINAGWATERSHED ARCTIC; Lhrd: DePce ECOPROVINCE/ECOREGION Northern Borerl Moontiinr: Boreal Mountains and Platcaus BIWEOCLIMATIC ZONE Bord White and Black Spruce

Figure A43 - Collection sites for Pisidium sp.

Mtasurement count 0brewcd TemperanuC (OC) 1 13 .%O Dissolved (% Saniration) 1 70.00 Conductivity (~Siemens) 1 93.60 Calcium (mdiüe) 1 12.62 DH 1 6.85 Discumion: This collection was Mémi tban otha Pisidium species collccted in thiD study but codd not be idmtifieû to @es. It sœmed to bat fit the dcsaption of Pisiditlm ultremontontrm but as this species bas ken w-ed for dangmd @a iisting in the United States (Frcst and Johanncs 1995), it did mt seem apploprirte to attach this @es name to rbis coilection mtil the identification can k confumed. Howemr, tbis imiâentified spacies may be an important component of the khwater moiius~ fauna of mrthan BC and its ecologid asesmat is incluàd hm. This collection was made hma

Tbis unbiown PUU6Yn sp. was an imoomrnnn mollusc of northcm BC king co11dat one of 176 sites. It waa found oniy in the Arctic drainage in the Northem BodMountains ecopmvince. The BGC zone in which it was foui hs a mean annuai taiipainin ranging hm-2.9 to 2.m with up to 7 montlu below 0.c and up to 4 month above 10°C and with annual precipitation ranging hm330 to 570 mm. Environmental Variables: The measures of the environmental variables for the site for Pisidium sp. are shown in Figure 2-14 as dots. Fi- 2-14 shows tbat Pisidium sp. was coîîected a a nlatively low t~mperature,average dissolvecl oxygcn, low conductivity, and avemge pH. The single collection dues not ailow the formation of any hypotheses as to the ecology of this species with regard to these fhctors.

The CCA results are that the Pisidium species are not nsponding signifidy to the environmental variables mdin this shidy (~~û.225)with 3.7% of the species presence accounted for (Figure 2-20). The plot shows Pisidium sp. to k associated with low pH and conductivity. The smd sample sue for this species does not aüow this placement on the plot to k intapreted ecologically.

If expert identification of this species does nsult in this collection being identified as P. ulrronianum, this wiîi be the nrst record for this species in BC. Nil sites

Sites w here freshwater molluscs were not collected

SlTES (6): N1013, N1024, N1045, N1079, N1086, N1087 DRAINAGWWATERSEED FACIFIC: Colaul: North Coast; Nass: Meziadin; Skeenr: Skeena ARCTIC: Pcrce: Smoky, Beatton; Urd: Fort Nelson ECOPROVINCE/ECOREGION Cout & Mo~ntrins:Coastai Gap (2), Northem Coastal Mo& Baml Plains: Central Alberta Uphds, Southem AlhUplandp Northern Bord Mountains: Northem Canadian RocLy Mountains BIOCEOCLIMGTIC ZONE Bord Black and White Sprue (2) Figure Ad4 - Ecologicai sites where moiiuscs wac not (2) collected. coastal westeni Wcmlock EngeImruin Spnice - Subalpine Fu (1) Spnice - Wiow - Birch (1)

Compuiron of nü rites and di other ecologicrl aita: Mcuiucment Mean and SE of sites Mean and SE of nU p =value df wîth mdluicr (plal) aite8@-6) Tembcraxure 18.96 f 0.44 16.18 f 1.79 p=0.148 112 Dissolvcd 0xyge1.1 68.61 f 2.19 55.17f 10.05 p=0.163 112 Coductivity 284.03 f 25.03 223.52 f 65.86 p =0.575 112 Calcium 41.05 f 3.73 28.63 f 8.85 ~=0.440 112

Site Descriptions: N1013: Large oligotropbic lakc, substrate of drocks; searched ana near boat launch only. N1024: Rdyabandoncd krva pond. Pond is aow full of gr= with a creek ruMing tbrough it. Thac wnc a few pools of standhg watu that Iippeand to offa suitable m~lluschabitat but none were found.

NIWS: Swept lots of vcgetatim and scooped bottom but no SUCCCSS. According to BC PAstaff, this Nil sites

lake freezes completely in the whter. N1079: Habitat, especiaiiy mud bottom, appeprs suitable but wata is very cold aud is probably corning hmnearby glacier. N1086: Appears to be suitable habitat; water brown and has very low pH. N1087: Water vny brown with low pH.

Whüe the above t-tests show that the sites where no mo11uscs were found diffd signdïcantly hmthe nst of the ecological sites in pH, thae may be other reasons why there were not molluscs found at these sites. Site N1013 may have had molluscs elsewhm in the lake but they were not found at the rocly, boat launch ana. SiteN0 124 had bea recently undergone dramatic changes fbm a large beaver pond to scattcrcd wet areas and there may not have ken SUfEicient the for thwe areas to becorne populated by molluscs. Site NI045 mes &!y in the winter leaving w refuge arc8 for mollws. Site N1079 was king fed by glacial melt ami so the wata source may be seasonal. Sites N1086 and 1087 wae close to cach otba and hed vay low pH, probably too low to provide mitable circumstanccs for shdl deposition in moliuscs. Figure A-65. The ccoprovinccs of mrthern British Columbia "a" indicatcs a colledion site.