Chemical and Biological Recovery of Killarney Park, Ontario

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CHEMICAL AND BIOLOGICAL RECOVERY OF KILLARNEY PARK, ONTARIO

LAKES (1972-2005) FROM HISTORICAL ACIDIFICATION

JUSTIN A. SHEAD

A thesis submitted to the Department of Biology

in conformity with the requirements for

the degree of Master of Science

Queen’s University

Kingston, Ontario, Canada

September, 2007

ABSTRACT

Forty-five lakes in Killarney Provincial Park and the surrounding area in south-

central Ontario, Canada, were sampled for crustacean zooplankton and water chemistry

in the summer of 2005. For each of the lakes, we had historic data from peak-

acidification in the 1970s and post-acidification periods in 1990 and 2000. Situated among the orthoquartzite ridges of the La Cloche Mountains in and near Killarney

Provincial Park, many of these lakes were acidified during the mid-1900s owing to

extensive mining and smelting activities in nearby (40-60 km) Sudbury, Ontario. There

is large variation in the geochemistry of the soils and the bedrock within the park. As a

result, these freshwater lakes have varying degrees of acidification, ranging from being

heavily acidified (pH < 4.5) to others that were buffered from the effects of acidic

deposition. With over 90% reductions in sulphur dioxide smelter emissions over the past

30 years and the present, many lakes in the Sudbury region are starting to show strong

evidence of chemical recovery. Despite significant increases in lake water pH, there is

limited evidence of biological recovery. A variety of univariate and multivariate metrics,

as well as variation partitioning, were used to examine recovery on a lake-by-lake basis

and on a regional scale. Our results revealed only moderate recovery of crustacean

zooplankton communities despite improvements in water quality. Some lakes increased

in zooplankton richness while others decreased compared to richness during peak

acidification. Shifts in community composition from a damaged state toward those

typical of circum-neutral lakes were observed for lakes that have chemically recovered.

The lack of chemical recovery is believed to be impeding biological recovery of many

lakes. Biological resistance and dispersal limitation do not appear to be hindering ii

biological recovery. Other stressors such as the invasion by the predatory zooplankton

Bythotrephes and climate change may delay biological recovery in the coming years.

Future recovery of Killarney Park lakes will require further chemical recovery for

biological recovery to become complete.

iii

CO-AUTHORSHIP

This thesis conforms to the Traditional format as outlined in the Department of Biology

Guide to Graduate Studies. Manuscripts that are to result from this thesis and their co- authors are listed below.

Manuscripts directly from this thesis:

Shead, J.A., S.E. Arnott, and A.M. Derry. In preparation for Ecological Applications.

Limited biological recovery of Killarney Park Lakes (Ontario) from historical

acid deposition despite chemical recovery: 1971-2005.

ACKNOWLEDGEMNENTS

First I would like to thank Shelley Arnott for giving me the opportunity to conduct this research and for allowing an “invasive species” into her lab. I would also like to thank her for her guidance throughout this process. I could not have asked for a better supervisor. Her passion for science and life is inspiring.

Thank you to my committee members John Smol, Linda Campbell, and Paul

Treitz for taking the time to be part of this process.

Many thanks go to the staff at the Freshwater Cooperative Ecology Unit in

Sudbury. In particular, Bill Keller, Jocelyne Heneberry, John Gunn, Shannon MacPhee, and Amanda Valois. Without their support this research could not have happened. I also would like to thank the staff at Killarney Park who helped with the logistics and to make this research possible.

I cannot say thank you enough to my lab mates for being there for me through thick and thin. Thanks to Angela “A-Train” Strecker for sharing her infinite wisdom with me and having my back through this entire process. To Alison “Big Al” Derry, I too thank you for your endless support and advice throughout this journey. Big thanks go out to other members of Team Arnott - Jessica Forrest, Liz Hatton, Shannon MacPhee, Mike

Pedruski, and Leah James for their support and making the lab a fun place to be. I also would like to thank all those that helped me in the field and the lab to whom I cannot say thank you enough.

Thank you to my friends for your constant moral support, our “deep” conversations at the Secchi table, and for always being there. To my “French Brother”

(a.k.a Le Moine), thank you for everything, you are a true friend. Last but certainly not v least, thank you to Isla for always being there, for sharing your tips as an “old pro”, and for being by my side through the good, the bad and the ugly.

Finally, to my family I cannot thank you enough for being the pillar of support that you have been through this process. Thank you for always believing in my abilities and your words of wisdom. Although provinces apart, you have always been there for me.

TABLE OF CONTENTS

ABSTRACT ………………………………………………………………………………i CO-AUTHORSHP.……….……….…….……..………………………………...…..…iii ACKNOWLEDGMENTS……...... …………………………………………………..…iv TABLE OF CONTENTS……….………...………………………………………….…vi LIST OF TABLES…...……………….……………….………………………………..vii LIST OF FIGURES……..…………………………………………………………..…viii

CHAPTER 1: GENERAL INTRODUCTION AND LITERATURE REVIEW...... 1

Crustacean Zooplankton as Biological Indicator Species………..………………..1 History of Acidification…...…..……….……….…….…….…………………… .1 Effects of Acidification…...…….…………………………………………………2 a) Chemical…………………………………………..……………………3 b) Biological………..………………………….……...... ………………3 Recovery……………….…...…..…………………………………………………4 Chemical Recovery……………..…………………………………………………6 Biological Recovery……....…….…………………………………………………7 Recovery Barriers……...... …….…………………………………………………7 Thesis Objectives……...... ….….……………………………………………….10

CHAPTER 2: METHODS ………………..……………………….…………………13

Study Site……………………………………..……….…….……….…………..13 Sampling Design…..……………..…………….….…………………………… .13 Lake Categories.……………………………………..…..………………………17 Statistical Analyses………..…………………………………………..…………17

CHAPTER 3: RESULTS……….…………………………………….………………23

Potential Drivers of Biological Recovery…..………………………………..… .29 Evaluation of Spatial and Environmental Factors….……………..….………….30

CHAPTER 4: DISCUSSION….……..…………………………….…………………57

Chemical Recovery……………..………………………………………………57 Biological Recovery……...... ….………………………………………………58 Barriers to Biological Recovery………………..………………………………61 Implications…………………………………….………………………………69

SUMMARY…………………...…………………………………….…………………73

LITERATURE CITED…………………………………………….…………………76

APPENDICIES…………...…….……………………...…….……….….……………86 vii

LIST OF TABLES

Chapter 2

TABLE 1. Selected physical characteristics of the 45 Killarney Park study lakes. Lake surface areas from Sprules (1975). Zmax = lake maximum depth, Secchi = secchi disk transparency.……………………………………………………………..…33

TABLE 2. Selected chemical and biological characteristics of the 45 Killarney Park study lakes. Lake water sampled as 5 m tube composite samples during July and August of 2005. Lake status defined as described in methods; acid = pH always < 6, recovered = pH increased from < 6 to > 6, circum-neutral = pH always > 6. Cond = Conductivity. TP = average total phosphorus from two samples taken at the same time. DOC = dissolved organic carbon, Ca = calcium, chl. a = chlorophyll a. Bytho and Fish = presence/absence of Bythotrephes and Fish respectively, 0 = absence, 1 = presence. Fish data from Snucins and Gunn (1998)………….. ……………………………………………………………..…35

Chapter 3

TABLE 4. Species names associated with ordination species code names. Arranged in alphabetical order of ordination code..………………………………………..…39

TABLE 5. Multiple regression of 1972 crustacean zooplankton species richness, diversity, evenness, and total abundance with predictor variables in all study lakes (n = 45). Predictor variables include pH, maximum depth, elevation, and total phosphorus. AIC = Akaike's Information Criterion, TP = total phosphorus....…40

TABLE 6. Multiple regression of 2005 crustacean zooplankton species richness, diversity, evenness, and total abundance with predictor variables in all study lakes (n = 45). Predictor variables include pH, maximum depth, elevation, and total phosphorus, dissolved organic carbon, and change in pH (measured as change in H+ concentration). AIC = Akaike's Information Criterion, TP = total phosphorus……...……………………………………………………………..…41

viii

LIST OF FIGURES

Chapter 1

FIGURE 1. SO2 emissions from the Sudbury, Ontario, area smelters (from Keller et al. 2007)……………………….….……………………………………………..12

Chapter 2

FIGURE 1. Killarney Park, Ontario, Canada. Shaded and black filled lakes indicate the lakes sampled within Killarney Park. Lakes Evangeline, La Cloche, Frood, and Charlton are located outside the park and therefore not shown on the map. Black lakes indicate previously observed presence of Bythotrephes. Shaded lakes have no previous Bythotrephes observations…………………………..42

Chapter 3

FIGURE 2. Linear regression between H+ concentration in 1972 (i.e., acidity) and chemical recovery (the change in H+ concentration between 1972 and 2005) for 45 Killarney Park lakes classified into three lake groups based on water quality improvements. Regressions are significant at p < 0.05……………..43

FIGURE 3. The frequency of pH in the 45 Killarney Park lakes in 1972 (black bars) and 2005 (white bars). pH of 6 is believed to a biological threshold in which below a pH of 6 you observe losses of acid sensitive species (Keller et al 2002)…………………………………………………………………………44

FIGURE 4. The frequency (percent lakes) for 45 Killarney Park lakes from 1972, 1990, 2000, and 2005 classified into 3 lake groups based on water quality improvements……………………………………………………….………..45

FIGURE 5. Long-term changes in average (a) species richness, (b) species diversity, (c) evenness (Evar), (d) and total abundance of crustacean zooplankton (number per liter) for 45 Killarney Park lakes from 1972, 1990, 2000, 2005 classified into 3 lake categories based on water quality improvements – acid (n=22), recovered (n=15), and circum-neutral (n=8). Error bars represent standard error...………………...…….….……………………………………………..46

FIGURE 6. Shift in zooplankton species dominance for lakes categorized based on water quality improvements (acid, recovered, and circum-neutral) in Killarney Park through time. Dominance is defined as the most abundant species in a given lake in a given year. From reading down the left column to the right column are species from the bottom of the diagram to the top…...…………………..47

FIGURE 7. Crustacean zooplankton distribution across Killarney Park lakes represented as the percentage of lakes occupied for 1972 and 2005. Lakes were divided into three categories: a) acid, b) recovered, and c) circum-neutral…………..48

FIGURE 8. Average a) zooplankton species turnover and b) time corrected species turnover between 1972 and 2005 calculated for 45 Killarney Park lakes grouped into 3 categories based on water quality improvements. Error bars represent standard error………………….…………………………………..49

FIGURE 9. Net species change for zooplankton communities (# appeared - # disappeared) between 1972 and 2005 for 45 Killarney Park lakes grouped into 3 categories based on water quality improvements. Lakes are arranged in increasing order of chemical recovery (i.e., H+ concentration). Grey bars indicate a net species gain. Black bars indicate a net species loss…………..50

FIGURE 10. Principal components analysis of 1972 zooplankton species abundances. Shown are a) sample and b) species. Species with short arrows were removed to reduce crowding. Species names can be found in Table 4…...…………..51

FIGURE 11. Principal components analysis of 2005 zooplankton species abundances. Shown are a) sample and b) species. Species with short arrows were removed to reduce crowding. Species names can be found in Table 4……...………..52

FIGURE 12. Shift in zooplankton community composition. Comparison of 1972 and 2005 PCA axis 1 scores for crustacean zooplankton communities of 45 Killarney Park lakes. Lake categories are based on water quality improvements. 1:1 indicates no change in community composition………..53

FIGURE 13. Relationship between chemical recovery (measured as change in H+ concentration, [H+]) and change (Δ) in a) species richness, b) species diversity, c) evenness (Evar), d) total zooplankton abundance, e) percent (%) species turnover, and f) PCA axis 1 between 1972 and 2005 for 45 Killarney park lakes. Lake categories based on water quality improvements. Only significant (p < 0.05) linear regressions are shown…..…………….………..54

FIGURE 14. Redundancy analysis of zooplankton species abundances and environmental conditions for a) 1972 and b) 2005. Environmental variables are represented by the large arrows and species by the small arrows. Species with short arrows were removed to reduce crowding. Species names can be found in Table 4. TP = total phosphorus, Zmax = maximum depth, Elev = elevation. Spatial variables are abbreviated e.g. soi5 = sphere of influence variable 5...... 55

FIGURE 15. Partitioning of variation in zooplankton communities in Killarney Park lakes in 1972 and 2005. The variation in species abundances is explained by purely environmental (env), purely spatial (sp), spatially structured environmental (sp-env) variables with the remaining being the residual variation (unexplained)…….….……………………………………………..56 1

CHAPTER 1: GENERAL INTRODUCTION AND LITERATURE REVIEW

Crustacean Zooplankton as Biological Indicator Species

Crustacean zooplankton (Phylum Arthropoda, Subphylum Crustacea) are a

diverse group of invertebrates found in all freshwater systems. They are good biological

indicators of recovery from disturbance (Walseng et al. 2003). Zooplankton are generally

small-bodied and have a relatively short generation time that ranges from weeks to

months. As a result, they are capable of responding to environmental changes such as

water quality improvements. Zooplankton are an essential part of aquatic food webs, occupying a central position between primary producers (phytoplankton) and both

planktivorous and piscivorous fish (Covich and Thorp 2001). Zooplankton produce

resting eggs that are viable for decades in lake sediments and can impact future lake

dynamics (Hairston et al. 1996). Finally, crustacean zooplankton exhibit a wide range of

acid-sensitivity that are species-specific, making them particularly useful for monitoring

changes in acidified systems (e.g., Walseng et al. 2003). Generally, pH of 6.0 is

considered the critical biological threshold of acid sensitive crustacean zooplankton

species in aquatic systems below which acid sensitive species are lost (Havens et al.

1993, Keller et al. 2002., Holt and Yan 2003).

History of Acidification

The term acid rain has long been used to describe the impact that industrial

emissions have had on precipitation. However, it did not become a major public issue

until the 1970s and 1980s in North America and Europe (Gunn and Sandøy 2003) when

widespread biological loss was observed (Beamish and Harvey 1972). 2

Acid rain has had drastic effects on freshwater ecosystems over the past century.

In North America, acid-sensitive regions in southeastern Canada and northeastern United

States experienced widespread acidification of freshwaters (Schindler et al. 1988).

Sudbury, Ontario, and surrounding area, including Killarney Park, has been particularly

affected by sulphur dioxide (SO2) emissions from base metal smelters (Sprules 1975,

Keller and Pitblado 1986). Sudbury smelters, once one of the largest sources of SO2 in

the world, dramatically altered the surrounding landscape with the acidification of over

7,000 lakes in the area (Neary et al. 1990).

In the early 1970s, SO2 emission regulations were legislated in North America as

a result of scientific consensus and public lobbying (Jeffries et al. 2003, Gunn and

Sandøy 2003). Since then SO2 emissions have been reduced by approximately 28% in

North America (Stoddard et al. 1999). Within the Sudbury region, SO2 emissions have

been drastically reduced by over 90% (Figure 1). While conditions in the Sudbury region

are improving, acid rain continues to be a growing problem in other heavily industrialized

countries such as China (Larssen et al. 2006).

Effects of Acidification

Acidifying agents, predominantly SO2, are emitted in elevated levels by several human activities including metal smelting operations (e.g. Keller et al. 1986). After

Beamish and Harvey (1972) found that acidification by atmospheric deposition from nearby Sudbury smelters caused widespread loss of fish species in lakes in and around the La Cloche Mountains, a large effort was put forward by the scientific community in

order to investigate and monitor the effects of acidification on freshwater lakes in this

region and other areas affected by acid rain. 3

a) Chemical

The geology of Killarney Park is diverse in terms of its buffering capacity for

acidification. The circum-neutral lakes in Killarney Park are situated on calcareous rocks

and soils. The high base cation concentrations of these limestone and sandstone bedrocks

have high neutralizing capacity that minimizes the negative effects of acidification

(Debicki 1982). Conversely, lakes associated with orthoquartize deposits around the La

Cloche Mountains have a low buffering capacity making them susceptible to acid

deposition (Sprules 1975). Although historically circum-neutral (Dixit et al. 2002, Keller

et al. 2003), the majority of these lakes were anthropogenically acidified by smelter

emissions from nearby Sudbury (Sprules 1975). In many Killarney lakes, pH in the early

1970s was below pH of 4.5, with one lake as low as 3.8 (Sprules 1975).

Acidified lakes in the Sudbury region, including Killarney Park, experienced

elevated concentrations of metals both from smelting activities (copper and nickel; Keller

and Pitblado 1986) as well as those leached from soil (aluminum and zinc; Keller et al.

2003). Based on diatom-inferred changes in dissolved organic carbon (DOC), water

transparency in some Killarney Park lakes is higher when compared to pre-industrial

conditions as a result of acidification (Keller et al. 2003).

b) Biological

Tens of thousands of boreal shield lakes were damaged by acid rain from metal

smelter emissions during the early half of the twentieth century. One of the first sites to

show damaging effects of lake acidification was the region around Killarney Provincial

Park and Sudbury, ON (Beamish and Harvey 1972). Mechanisms by which acidification can act upon biota can be either direct or indirect. Direct mechanisms include toxicity 4

and physiological stress (summarized by Økland and Økland 1986, Havas and Rosseland

1995; e.g. Nero and Schindler 1983, France 1987), whereas indirect effects include

alteration of normal predator-prey interactions (e.g., Erikson et al. 1980, Yan et al. 1991).

The influence of pH on structure and diversity of freshwater organisms is well

documented (e.g., Marmorek and Kormen 1993). The effects of acidification on

crustacean zooplankton communities in particular have been thoroughly researched. A

combination of surveys (e.g., Sprules 1975), experimental studies (e.g., Schindler et al.

1985), and laboratory experiments (e.g., Keller et al. 1990, Locke et al. 1991) have

provided insight into the effects of acidification on zooplankton. As lake pH decreases,

abundances of acid-sensitive zooplankton species such as Daphnia mendotae, Daphnia

retrocurva, and Skistodiaptomus oregonensis decrease while an acid tolerant species,

Leptodiaptomus minutus increases (Sprules 1975). Similarly, the abundance of the

acidophile rotifer Keratella taurocephala increases in lakes with low pH (Schindler et al.

1985, MacIsaac et al. 1986). At low pH, phytoplankton communities sustain losses of

diatoms while abundance of chlorophytes increase (Schindler and Turner 1982). Other

aquatic biota lost in lakes with low pH includes benthic invertebrates (Schindler et al.

1985, Harvey and McArdle 1986) and fish (Beamish and Harvey 1972). Not limited to

aquatic systems, anthropogenic acidification caused large-scale loss of vegetation in the

Sudbury area (Gorham and Gordon 1960).

Recovery

With growing evidence of the effects of acidification described above,

government and industries were pressured by the public and environmental groups to take

action (Gunn and Sandøy 2003). Legislated control programs and modernization 5 initiatives by industry have resulted in a significant reduction of sulphur emissions and subsequent decreases in surface water concentrations of sulphate in North America and

Europe (Stoddard et al. 1999, Jeffries et al. 2003). As a result of 90% reductions in emissions from Sudbury smelters, many lakes in Killarney Provincial Park have demonstrated remarkable chemical recovery (Keller et al. 2003).

Although the effects of acidification on aquatic systems are well known, much less is known about the chemical and biological recovery as emissions and acid inputs subside. As a result, research shifted towards examining the trends and processes of chemical and biological recovery (Gunn and Keller 1998).

Assessing recovery is not a simple task. There are multiple ways that biological recovery can be assessed. The preferred approach is to compare stressed communities with pre-disturbance communities. This approach has been used for experimentally acidified lakes (e.g., Findlay and Kasian 1996, Mills et al. 2000, Frost et al. 2006).

However, when acidification is the result of industrial activity, there are often no historical pre-acidification data for comparison. Current advancements in paleolimnological techniques can provide insights into pre-disturbance conditions from diatom, chrysophyte, and cladoceran zooplankton communities of acidified lakes when historical data are lacking (Smol 1992). While these techniques have proven invaluable for inferring historical conditions in many lakes, they are limited for soft bodied organisms, such as copepods, that do not leave a record of identifiable body parts in the lake sediments (Korhola and Rautio 2001). In the absence of historical data, often damaged communities are compared to circum-neutral communities (e.g., Yan et al.

1996b, Holt and Yan 2003). By comparison to circum-neutral communities, managers 6

can set recovery targets. However, with the potential effects of multiple stressors such as

climate change (e.g., Schindler 2001) and invasive species (Strecker et al. 2006), targets

set by pre-disturbance communities may be completely altered.

Definitions of recovery can differ. A variety of univariate and multivariate metrics have been used to describe the recovery of zooplankton from acidification. These include species richness, diversity, evenness, biomass, and species composition (Yan et al. 1996b, Arnott et al. 2001). A strong relationship between crustacean zooplankton species richness and pH has been well documented (Marmorek and Kormen 1993).

Univariate metrics tend to show variable and limited evidence of biological recovery and ignore species interrelationships (Yan et al. 1996b). As a result, Yan et al. (1996b) and others (Arnott et al. 2001, Holt and Yan 2003) recommend the use of multivariate

techniques that incorporate the relative abundances of multiple taxa. They have found

multivariate methods to be more sensitive than univariate methods when exploring

differences among communities observed at different sites or times. The strongest

evidence of biological recovery in Killarney Park is obtained using multivariate metrics

examining changes in community composition compared to communities of circum-

neutral lakes (Holt and Yan 2003).

Chemical Recovery

2- Legislated reductions in SO2 have resulted in significant decreases in SO4 and increases in alkalinity across North American and Europe in regions where acidification has been a major issue (Stoddard et al 1999, Jeffries et al. 2003, Skjelkvåle et al. 2005).

However, increases in alkalinity are somewhat inconsistent in certain regions of the world suggesting that there is a lag in the expected chemical recovery of lakes (Stoddard 7

et al. 1999). With significant reductions of SO2 emissions from base metal smelters in

Sudbury (Figure 1), lakes within the region, including those in Killarney Park, were some of the first sites to show evidence of chemical recovery as a result of emission reductions

(Keller and Pitblado 1986, Keller et al. 1986, Keller et al. 2001a, Snucins et al. 2001,

Keller et al. 2003). Several Killarney Park lakes have recovered to diatom-inferred pre- disturbance pH levels (Keller et al. 2003). Other observed changes include decreases in base cations, such as calcium, and metals (e.g., Cu and Al) as a result of decreasing sulphate concentrations and associated leaching from the catchments (Keller et al. 2003).

Despite these improvements in water quality in Killarney Park lakes, many lakes were still acidic in 2000 (Holt and Yan 2003, Keller et al. 2003). Further monitoring is necessary to track additional recovery.

Biological Recovery

To date, evidence of large-scale biological recovery of aquatic organisms from

anthropogenic acidification in North America and Europe is limited. With improvements in water quality, it is believed that biological recovery will follow. Promising evidence of this is seen in the Sudbury region where chemical recovery has been substantial (e.g.,

Keller et al. 1992a). In Killarney Park, damaged communities of phytoplankton (Findlay

2003), zooplankton (Holt and Yan 2003), and benthic invertebrates (Snucins 2003) are showing evidence of recovery in community composition and the return of acid-sensitive species as a result of emission reductions. Recovery of aquatic biota including zooplankton was not complete based on a lake survey in the summer of 2000 (Holt and

Yan 2003).

Recovery Barriers 8

The recovery of crustacean zooplankton from acidification is complex and can be impacted by several internal and external factors (Keller and Yan 1998). For instance, biological recovery is expected to be delayed until the pH of acidified lakes is above the biological threshold of acid-sensitive species (pH 6.0) (Holt and Yan 2003). Other factors including biological resistance by acid-shaped communities (Yan et al. 1991,

Keller and Yan 1998, Arnott et al. 2006), colonization barriers (Yan et al. 2003) and additional stressors such as climate change (Yan et al. 1996a, Arnott et al. 2001, Snucins and Gunn 2000, Keller et al. 2005) and the introduction of exotic species (Strecker and

Arnott 2005) are potential barriers for biological recovery. The relative importance of these factors for Killarney Park lakes remains relatively poorly understood.

The biological recovery process proposed by Yan et al. (2003) suggests a sequence of essential steps that is influenced by a number of local and dispersal-related processes. Potential colonists will not be successful until local conditions are favorable.

This requires at least that surface water pH be above the biological threshold of acid- sensitive zooplankton species of pH 6.0 (Holt and Yan 2003). Once local environmental conditions are habitable, potential colonists can arrive from a variety of sources.

Zooplankton can colonize lakes from both within and outside lake sources. Within-lake sources include historically deposited resting eggs or diapause stages in the sediment

(Hairston et al. 1996) and populations within the lake that maintain low abundances in refuges during stress (Keller et al. 1998). External sources of potential colonists can immigrate into lakes from nearby lakes or rivers by wind (Cáceres and Soluk 2002), water connections (Michels et al. 2001), animal vectors (Proctor 1964, Maguire Jr. 1963), or human activity (Havel and Shurin 2004). 9

Local environmental and dispersal barriers can shape crustacean zooplankton

communities, including those recovering from acidification. Past studies focused on

attempting to explain the variation of zooplankton in a region with either environmental gradients (e.g., pH, nutrients, and lake morphology) or biological factors (predation).

Pinel-Alloul et al. (1995) first tested the hypothesis that both abiotic and biotic factors, as

well as spatial structuring, explain the large-scale spatial variation of freshwater

zooplankton. This method allowed for variance to be partitioned into 4 parts: a) pure

environmental factors (chemical, physical, and biotic parameters), b) spatially-structured

environmental components, c) pure spatial factors (geographic coordinates), and d) unexplained. This study showed that 48% of the zooplankton variation was explained by

pure environmental and spatially-structured environmental factors (a + b). Purely spatial

factors explained only 8% of the variation with the remaining 44% unexplained

suggesting that other forces not taken into account are influencing zooplankton

community composition and structure (Pinel-Alloul et al. 1995). This supported their

multiple forces hypothesis that all three factors (abiotic, biotic and spatial) play a role in explaining variability in zooplankton.

After the findings of Pinel-Alloul et al. (1995) were published, interest in the role

of the spatial configuration (i.e., the dispersal from lake to lake) increased. One of the

tools developed as a result of this research was using variation partitioning in

combination with multivariate techniques. Environmental variables normally put into

redundancy analyses (RDA) can be combined with spatial factors and then partitioned into the respective fractions (a, b, c, d). Using this method, the importance of purely spatial factors can be thought of in terms of dispersal, with large amounts of variation 10

explained by pure spatial factors suggesting dispersal limitation. Cottenie (2005) found

an approximately equal amount of the community composition variation explained by

both space and environmental factors (total 50%) compared to Pinel-Alloul et al. (1995)

who determined environmental factors were more important. Another key study by

Beisner et al. (2006) found differences in the contribution of each fraction for different

trophic levels of aquatic food-webs. They indicated that dispersal plays an important role

in determining community structure of aquatic organisms. In particular, crustacean

zooplankton were found to be limited by dispersal. This may be a powerful technique for

examining processes (environmental and dispersal) involved in structuring communities

recovering from acidification.

Thesis Objectives

The overall objective of this thesis was to assess the chemical and biological

recovery of Killarney Park lakes in a region that has been historically acidified.

Historical survey data from the early 1970s to 2000 were available allowing us to

compare conditions at the point of severe chemical and biological damage sustained by

aquatic ecosystems due acidification to post-emission reduction conditions.

Using historical data on 45 Killarney Park lakes, in combination with data

collected in this study in the re-surveying of these lakes in 2005, the following main

objectives were addressed: (1) to assess the extent of chemical and biological recovery in

Killarney Park lakes; (2) to describe the relationship between environmental variables and biological metrics that describe crustacean zooplankton species richness and composition; (3) to determine the driving factors in crustacean zooplankton recovery from historical acidification and the roles of environmental and spatial variables; (4) to 11 assess how many lakes in Killarney Park have been invaded by the predatory, invasive zooplankton Bythotrephes longimanus. 12

3000

2500

2000

1500 (kilotonnes) 2 1000 SO

500

0 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year

FIGURE 1. SO2 emissions from the Sudbury, Ontario, area smelters (from Keller et al. 2007) 13

CHAPTER 2: METHODS

Study Site

Killarney Provincial Park (46°05’N, 81°35’W), a 48,000-hectare wilderness park,

is located 40-60 km southwest of the metal smelters of Sudbury, Ontario, Canada (Gunn

and Sandøy 2003). The landscape is characterized by the white ridges of the La Cloche

Mountains, composed primarily of orthoquartzite, and within the park there are over 600 lakes and ponds with pH ranging from 4.3 to 7.6 (Snucins et al. 2001). There is large variation in the geochemistry of the soils and the bedrock within the park. As a result, lakes were acidified in the mid 1900s to varying degrees, with current lake pH ranging from 4.4 to 7.8. These lakes cover a broad range of physical (Table 1) and chemical

(Table 2, Appendix 1) gradients. The study lakes vary relatively little in elevation (range:

182 – 298 m), but differ substantially in lake size (range: 3.4 – 1088.3 ha), maximum depth (range: 2.4 – 57 m), and secchi depth (range: 1.4 – 28 m). Chemically, these lakes cover a broad range of conductivity (17.4 – 68.0 μS/cm), total phosphorus (1.2 – 19.4

μg/L), dissolved organic carbon (0.1 – 10 mg/L), and base cations (e.g., Ca2+, 0.4 – 8.8

mg/L).

Sampling Design

The study concentrated on forty-five lakes that have been previously sampled

during the course of emission reductions within this region (Figure 1). The lakes were

first sampled in the 1970s during peak industrial SO2 emissions (Sprules 1975) and then

in 1990 (Locke et al 1994) when emissions in the Sudbury region declined and

substantial reductions in lake acidity had been documented (e.g., Keller et al 1986). In

2000, Holt and Yan (2003) reassessed chemical and biological recovery after further 14

reductions in emissions and improvements in regional water quality (Snucins et al 2001).

Data from these surveys have revealed limited recovery of zooplankton communities

with improvements in water chemistry.

We re-sampled these forty-five lakes in Killarney Park and surrounding area in

2005 for crustacean zooplankton composition, phytoplankton biomass (chlorophyll a),

and water chemistry. During daylight hours between July and August, all lakes were

sampled once at the point of maximum depth in the major basin of each lake. Maximum

depth was determined from either bathymetric maps (Snucins and Gunn 1998) or

scanning the lake with a depth finder.

In each lake, a single crustacean zooplankton sample was taken by pulling a

conical net with 80 μm mesh size and 25 cm diameter through the water column, starting

2 m off the lake bottom. In shallow lakes (< 2 m), horizontal hauls of 2 m were taken.

Zooplankton samples were anesthetized by adding a small quantity of Bromo-Seltzer® to the sample, and then preserved in the field in 4% sugared and buffered formalin. We also sampled each lake for Bythotrephes longimanus, an invasive predatory zooplankton that had been previously detected in several lakes in the region. Bythotrephes was sampled at five stations in each lake, including the sampling station where zooplankton was sampled.

A conical net with a 35 cm diameter and 400 μm mesh size was hauled from 2 m off the lake bottom to the surface for Bythotrephes.

Sampling methodologies for zooplankton were similar among the historic and

2005 surveys, with some minor deviations. Sprules (1975) collected zooplankton from

July to September in 1972 with a conical tow net of 30 cm diameter with 75 μm mesh and in 1973 with a 25 cm diameter net with 100-μm mesh. Zooplankton and water 15

chemistry were taken in the same year but not always on the same day. Locke et al.

(1994) sampled the same mid-lake sites once during daylight hours in August in 1990.

Three hauls from near bottom to surface were collected using a 25 cm diameter conical

net with mesh size of 76 μm and pooled. Holt and Yan (2003) collected zooplankton and

pH samples in July and August of 2000 from the same set of lakes at the same mid-lake sites. At each site, three vertical zooplankton hauls were taken using a 12.5 cm diameter

net of mesh size 80 μm. To determine the effect of net size on zooplankton community

description, Holt and Yan (2003) sampled 4 lakes with both a 30 cm diameter net of

mesh size 80 μm (single haul) and a 12.5 cm diameter net of mesh size 80 μm (3 hauls).

They found no statistical difference in the species richness or logged abundances of 17

dominant species, except Bosmina (Neobosmina) tubicen and Holopedium gibberum,

both acid-tolerant species, and as a result, they concluded that net size did not have an

influence on the ability to detect community change.

Zooplankton were enumerated using a protocol designed to target mature

individuals as well as ensuring reasonable representation of rare species (Girard and Reid

1990). Crustacean zooplankton were identified and enumerated using a Leica MZ 16

dissecting microscope. Successive sub-samples representing between 0.4% and 4%

(depending on the density of the zooplankton in the sample) of standardized 200-mL

sample volume were removed with a wide-bore pipette until a minimum total of 250

individuals were enumerated, such that the maximum contribution of each individual taxa

to the total count was less than 50 for adults and copepodids, and no more than 30 for

copepod nauplii, even though more may have been enumerated. 16

Crustacean zooplankton were identified to the species level when possible.

Taxonomic keys that were used included Hebert (1995) and Dodson and Frey (1991) for

cladocerans, Smith and Fernando (1978) for copepods, Taylor et al. (2002) for

Bosminidae, and Smith (2001) for general zooplankton identification. Because of the

uncertainty in identification and taxonomic discrepancies among studies, Bosmina spp.

(Taylor et al. 2002) and Eubosmina spp. were pooled. Diaphanosoma brachyurum and

Diaphanosoma birgei were also pooled and are referred to herein as D. birgei because of

misclassification from historical surveys (Kořínek 1981). Immature copepodite stages

could usually only be identified to order except for late stages of Epischura lacustris and

Senecella calanoides. Copepod nauplii were enumerated but not identified. However,

immature copepods were excluded from all analyses. Taxonomic revisions during the

period from 1975 to 2005 are listed in Appendices 3-6.

Water samples for chemistry and chlorophyll a were taken at the same time and

location as zooplankton samples for each lake. A vertical integrated water sample was

collected using a 5 m tube sampler (2.54 cm inner diameter) and kept cold until analysis. pH, conductivity, total phosphorus, dissolved organic carbon (DOC), calcium, as well as other chemical variables (see Appendix 1) were analyzed following Ontario Ministry of the Environment protocols (see Appendix 2) at the Dorset Environmental Science Centre in Dorest, Ontario. pH and conductivity were also measured using a PHM64 Research pH meter (Bach Simpson Ltd, London, ON, Canada) and WTW inoLab 740 pH/conductivity meter (WTW Inc., Woburn, MA, USA) respectively. Water for chlorophyll a analysis was divided into three subsamples. Each subsample was filtered through a Pall™ Ultipor glass filters (1.2-μm pore size) which was then frozen and kept 17

in darkness for later chlorophyll a analysis. Chlorophyll a samples were extracted in

methanol for 24 hours in the dark in a refrigerator before analyzing with a TD 700

Fluorometer (Tuner Designs, Sunnyvale, California, USA).

Lake Categories

The 45 lakes were categorized into three lake groups based on water quality

improvements according to changes in pH by comparing historical levels (Sprules 1975)

to current pH levels. The three lake categories are:

1) Acid lakes (n = 22) had pH below 6 in 1972 and remained below pH 6 in 2005.

2) Recovered lakes (n = 15) had pH below 6 in 1972 and rose to pH 6 or greater

in 2005.

3) Circum-neutral lakes (n = 8) have had pH above 6 since 1972, probably

resulting from high buffering capacity.

Statistical Analyses

Linear regression was used to assess the relationship between the hydrogen ion

(H+) concentration of the study lakes during peak acidification in 1972-73 and the change in H+ concentration from 1972-73 to 2005. Chemical recovery was also assessed by

observing shifts in the distribution of pH in lakes across the landscape between 1972-73 and 2005 using a Chi-square test (Zar 1999).

Following Yan et al (1996b), we investigated several univariate and multivariate

zooplankton community indices to assess biological recovery. The univariate metrics

were species richness, diversity, evenness, and total crustacean zooplankton abundance.

Species richness was chosen because it has been well documented to be strongly related

to pH (e.g. Marmorek and Korman 1993, Yan et al. 1996b). Species richness for each 18

lake was calculated based on the total number of species (or in some cases, genera)

detected, excluding juveniles (Magurran 2004). Diversity was calculated using the

Shannon-Wiener index of entropy with a correction suggested by Jost (2006) that

transforms it into a measure of diversity.

(1) Diversity = eH

Where H is Shannon-Wiener index of entropy (H = -Σpilogpi). Evenness was assessed

using Evar, an index recommended for general use (Smith and Wilson 1996).

⎛ S ⎞ pi)ln( ⎜ S ∑ ⎟ ⎜ i=1 2 ⎟ ln( pi − ) ⎜ ∑() ⎟ 2 i=1 S (2) Evenness = Evar = 1 - arctan⎜ ⎟ π ⎜ S ⎟ ⎜ ⎟ ⎜ ⎟ ⎝ ⎠ Evenness ranges from 0 (minimum evenness) to 1 (maximum evenness). Diversity,

evenness, and total crustacean zooplankton abundance were calculated using adult

species abundances. Although we had limited power with only 4 sample dates for each lake, we used ranked correlation, Spearman’s ρ, to detect monotonic trends in zooplankton indices through time. Although we detected some negative relationships, one-tail tests were used as we were interested in only unidirectional positive changes that we expect would be associated with chemical recovery (Siegel and Castellan 1988).

We assessed regional changes in zooplankton community structure using the

identity and frequency of occurrence across the landscape of the dominant species in each

lake. We defined dominant species as the most abundant species in a given lake in a

given year. We also examined the distribution of species across the landscape by

comparing 1972-73 and 2005. The frequency of occurrence, i.e., the number of lakes 19

occupied, of all zooplankton species was compared among years using a Chi-square test

(Zar 1999).

Changes in species composition through time were assessed by calculating

species turnover in each lake (Magurran 2004). The change in species between sample

periods 1972-73 (t1) and 2005 (t2) was assessed using:

(3) Species Turnover = (# species gained + # species lost)/(richness at t1 + richness at t2).

Species turnover was also corrected for time by dividing species turnover by the time between the two surveys. Because species turnover is influenced by the number of species in the lake, we also assessed compositional change as:

(4) Net Species Change = (# species gained - # species lost)

Principal components analysis (PCA), a linear ordination technique, was used to describe the community structure in 1972-73 and 2005 after preliminary indirect gradient analysis (1972-73: 3.32, 2005: 2.67) using detrended correspondence analysis (DCA).

Gradient lengths ranging from 3 to 4, both linear (principal components analysis, PCA) and unimodal (correspondence analysis, CA) methods work well, whereas for gradients shorter than 3, linear methods are preferred (Lepš and Šmilauer 2003). Linear techniques

(PCA) were used for 1972-73 and 2005. Species abundances were Hellinger-transformed to reduce the influence of rare species (Legendre and Gallagher 2001). Analyses were performed using CANOCO v. 4.5 with scaling focusing on interspecies correlations (ter 20

Braak and Šmilauer 2002). Hellinger-transformed species abundances from all lakes in

1972-73 were run actively with the 2005 abundances to estimate the change in

zooplankton community composition between the two time periods. Lake categories are

separated along the first PCA axis with acid lakes at one end (low axis 1 scores) and

circum-neutral lakes at the other (high axis 1 scores). Axis 1 sample scores (45% of the

variation in the species composition explained) for 2005 were plotted against axis 1

scores for 1972-73. The one-to-one line indicates no change, whereas points above the

line indicate recovery defined as a change in species composition to more closely

resemble circum-neutral lakes (i.e. shifts in axis 1 to higher scores).

We assessed the mechanisms driving zooplankton community structure with

water quality improvements using linear regression. We examined the relationship

between chemical recovery (H+ change) and change between 1972-73 and 2005 for each

measure of biological recovery; change in species richness, diversity, evenness (Evar), total crustacean zooplankton abundance, species turnover, and PCA axis 1 scores.

To determine the environmental variables driving the community structure of zooplankton in both 1972-73 and 2005, we used multiple linear regression analysis with the best subsets procedure in Statistica v.6.0 (StatSoft 2001). Relationships between species richness, diversity, evenness, and total crustacean zooplankton abundance were assessed with the following environmental variables: pH, elevation, maximum depth, and total phosphorus (TP). These four environmental variables were the only variables for which we had data in both years. In addition to the four environmental variables, change in H+ concentration from 1972-73 to 2005 and dissolved organic carbon were included in

the multiple regression analyses of the 2005 data. We tested for collinearity of 21

environmental predictor variables. Surface area was removed from the analysis due to

collinearity with maximum depth as indicated by a high (> 10) variance inflation factor of

the predictor (Quinn and Keough 2002). When the assumptions of multiple regression -

normality, heterogeneity of variance, and independence – were violated, we transformed

predictor and response variables accordingly. Assumptions were tested using boxplots,

plots of residual against ŷi and correlation matrices. For 1972-73 analyses, species

diversity, evenness (Evar), total zooplankton abundance, and total phosphorus were log10-

transformed. For 2005 multiple regression analyses, total zooplankton abundance,

evenness (Evar), total phosphorus were log10-transformed, whereas species diversity and

dissolved organic carbon were square root-transformed. The best model with the highest

predictive power was chosen by comparing the adjusted coefficient of determination

2 (adjusted r ), Mallow’s Cp, and Akaike’s information criterion (AIC) for each model

2 (Quinn and Keough 2002). High values of adjusted r and small values of Mallow’s Cp and AIC indicate the best model.

To assess the relative role of spatial factors (i.e., dispersal) and local environmental factors on zooplankton community composition and recovery, we used a combination of spatial modeling and ordinations. Spatial modelling of study lakes was conducted according to Borcard and Legendre (2002), Dray et al. (2006) and Griffith and

Peres-Neto (2006), using the program R v.2.4.0 (R Development Core Team 2006).

Spatial variables were created by first converting GPS coordinates of the sampling sites to UTM (Universal Transverse Mercator) coordinates. Then with the use of the program spacemakeR (Dray 2006), we generated eigenvector maps from the UTM coordinates.

Four models were created. Varying in the amount of connectivity, the models used (from 22

highest to lowest amount of connectivity) were Delaunay triangulation, Gabriel, relative neighbour, and sphere of influence (Legendre and Legendre 1998). Using each of these models, spatial variables were derived as a series of eigenvectors and subsequently used

in ordinations (see below).

Detrended correspondence analysis (DCA) of Hellinger-transformed crustacean

zooplankton species abundance was conducted for 1972-73 and 2005 separately. From

the gradient lengths it was determined that redundancy analysis (RDA) was appropriate

(Lepš and Šmilauer 2003). Rare species (occurrence: < 3 lakes) were removed.

CANOCO 4.5 (ter Braak and Šmilauer 2002) was used to perform RDAs using 1972-73

and 2005 zooplankton species, environmental and spatial data. Samples were centered

and standardized to adjust for differences in measurement units of environmental

variables, making them comparable (Lepš and Šmilauer 2003). Spatial and

environmental variables were forward-selected by Monte Carlo permutation tests at

p<0.05 with 499 iterations.

Each model was tested with Hellinger-transformed species abundances,

environmental variables (pH, elevation, maximum depth, and total phosphorus) and the

generated series of spatial eigenvectors. Total variation was partitioned into fractions

which comprised of: 1) purely spatial; 2) spatially-structured environmental; and 3)

purely environmental. To adjust for bias in R2, VarCan v.1 was used (Peres-Neto 2006).

The model with smallest residual variation in both 1972-73 and 2005 analyses was

selected.

All statistical analyses unless otherwise mentioned above were performed using

Statistica 6.0 software (StatSoft Inc.). 23

CHAPTER 3: RESULTS

There was strong evidence of chemical recovery in the Killarney Park lakes. In

all lakes, except Little Superior, pH increased from 1972-73 to 2005. Generally, lakes

that were most acidic in 1972-73 showed the most recovery in terms of change in H+ concentration (Figure 2). Gail Lake was an outlier, but had low leverage and did not alter the relationship between 1972-73 H+ concentration and the amount of chemical recovery

(r2 = 0.92, p < 0.01 including Gail Lake and r2 = 0.85, p < 0.01 excluding Gail Lake).

Despite the large change in H+ concentration, Gail Lake remained an acidic lake in 2005.

We also detect strong evidence of chemical recovery in terms of a significant shift towards higher pH among the study lakes between 1972-73 and 2005 (Figure 3, χ2 =

41.59, p < 0.01). Although there was an increase in pH in all of the lakes that were circum-neutral (pH > 6) in 1972-73, the change in H+ concentration was minor. The

number of circum-neutral lakes increased from 8 in 1972-73 to 23 in 2005, indicating that

15 lakes had chemically recovered to a pH > 6. In 1972-73, there were 23 lakes that were severely acidified (pH < 5). By 2005, there were only 6 lakes in this severely acidified category – Gail, Little Superior, Nellie, Proulx, Shingwak, and Whiskeyjack (Figure 4).

Despite improvements in water chemistry, we found limited evidence of

biological recovery. Species richness varied in 2005 from 2 to 14 (mean 7.1 species).

Whereas five lakes (acid lakes – Little Superior, Norway, Proulx, Shingwak, and

Whiskeyjack) contained one species in 1972-73, we detected at least 2 species in each

lake in 2005. Species richness in acid lakes was consistently lower than the other 2 lake

groups (ANOVA, F = 10.70, p < 0.01). Acid lakes were significantly lower in 2005

(Tukey p < 0.05) compared to recovered and circum-neutral lakes that did not statistically 24

differ (Tukey p > 0.05). Mean zooplankton species richness tended to increase in acid

lakes through time, although peak mean richness occurred in 1990 (Figure 5a). In

circum-neutral and recovered lakes, there was an initial increase in mean zooplankton

species richness with the onset of emission reductions from 1972-73 to 1990. However,

from 1990 to 2005, mean zooplankton species richness decreased to the mean richness

observed in 1972-73, and in some lakes below the 1972-73 level. On the other hand, the trend of increasing species richness through time was statistically significant for only

14% of the acid lakes (Table 3). Approximately half of the recovered lakes had positive

trends in species richness; however, none were statistically significant. Circum-neutral

lakes maintained species richness or tended to lose species: one lake (Helen Lake) had a

significant decline in richness and negative trends in richness through time were seen (4

of 8 lakes). Interestingly, Helen Lake has been recently invaded by Bythotrephes

longimanus.

Species diversity, measured as corrected Shannon-Weiner diversity, ranged from

1 to 9 (mean 3.5). Species diversity, like species richness, was consistently lower in acid

lakes compared to recovered and circum-neutral lakes (Figure 5b, ANOVA, F = 14.71, p

< 0.01). Diversity in 2005 was significantly lower in acid lakes (Tukey p < 0.05)

compared to recovered and circum-neutral lakes, that did not statistically differ (Tukey p

> 0.05). There was no change through time in species diversity in acid lakes. Individual

trend tests indicated that the majority of lakes had positive correlations but only 10%

were statistically significant (Table 3). There was a general trend of increasing diversity

in recovered lakes but only ~13% of the lakes showed statistically significant trends. 25

Circum-neutral lakes revealed a mixture of both increasing and decreasing trends in diversity with one significant decreasing trend in Gem Lake (Table 3).

Evenness, Evar, ranged from 0.04 to 1 (mean 0.3). Circum-neutral lake evenness

remained relatively consistent throughout time with a slight decrease from 2000 to 2005

(Figure 4c). The community evenness of the acid and recovered lakes had similar

patterns through time with a decrease from 1972-73 to 1990 followed by an increase in

2000. In 2005, acid lakes evenness decreased while evenness in recovered lakes did not

change. Approximately 13% of the acid lakes had a decrease in evenness through time

(Table 3). Evenness in individual circum-neutral and recovered lakes did not change

through time (Table 3). In 2005, evenness was similar among all lake categories

(ANOVA, F = 0.88, p = 0.42).

Total crustacean zooplankton abundance varied substantially among lakes

ranging from 0.1 to 115.8 (mean 24.4) individuals per liter. All three lake groups

followed similar patterns through time with a decrease in abundance from 1972-73 to

1990. Total abundance in circum-neutral and acidic lakes increased from 1990 to 2005,

whereas total abundance in recovered lakes decreased from 2000 to 2005 (Figure 5d).

Abundance was highly variable among lakes and, therefore, we did not detect a statistical difference in total abundance among lake categories in 2005 (ANOVA, F = 2.16, p =

0.13). Approximately 14% of acid lakes had significant decreasing trends in total zooplankton abundance through time (Table 3). Only one circum-neutral lake had a significant increasing trend in total abundance, whereas total abundance in the remaining recovered lakes did not significantly change through time (either positive or negative). 26

In 1972-73, the numerically dominant zooplankton species in ~ 73% of the lakes

was Leptodiaptomus minutus, a small, acid-tolerant calanoid copepod (Figure 6). As lakes recovered, other taxa including Bosmina spp., Diacyclops bicuspidatus thomasi, and Diaphanosoma birgei gained dominance in many lakes (Figure 6a, b). Daphnia mendotae, a highly acid sensitive cladoceran with a pH threshold tolerance of 6 (Havens et al 1993) was the dominant zooplankton in one recovered lake (Frood Lake) after 2000.

In circum-neutral lakes, the diversity of dominant species was high relative to acid and recovering lakes (Figure 6c). Interestingly, in 2005 the same species dominate both acid and circum-neutral lakes (Figure 6a and c). Dominance patterns in circum-neutral lakes shifted through time, likely the result of stochastic shifts in relative abundance of common species and time of sampling. In general, circum-neutral lakes are dominated by acid-sensitive species, including Daphnia mendotae, Daphnia longiremis, Daphnia retrocurva, Tropocyclops extensus, and D. b. thomasi (Figure 6c).

Most species were rare in the landscape and tended to be found in less than 25%

of the lakes we sampled (Figure 7a-c). This pattern was more pronounced in 2005 where

the percentage of species that were geographically rare in acid, recovered, and circum-

neutral lakes was 56%, 65%, and 57% respectively. Recovered and acid lakes had few

geographically common species, with L. minutus being the only widespread species in

acid lakes. Despite improvements in water chemistry, the distribution of zooplankton

species across the landscape for acid and recovered lake categories did not change

between 1972-73 and 2005 (acid: χ2 = 3.98, p < 0.41; recovered: χ2 = 5.07, p < 0.28)

(Figure 7a, b). However, there was a significant shift between 1972-73 and 2005 in the

zooplankton distribution across the landscape for circum-neutral lakes (Figure 7c, χ2 = 27

10.53, p < 0.32). In 2005, circum-neutral lakes had approximately 13 species that were

found in less than 25% of the lakes, compared to 6 in 1972 (Figure 7c). There were 6 widely distributed species that could be found in more than 75% of the circum-neutral lakes in 2005, compared to the 8 in 1972. These 6 common taxa found in circum-neutral lakes in 2005 include a combination of acid-sensitive and acid-tolerant species – L. minutus, Bosmina spp., D. mendotae, H. gibberum, D. b. thomasi, and Mesocyclops edax.

Species turnover measures the stability of communities through time (Magurran

2004). Species turnover was significantly higher in acid lakes (Tukey p < 0.05)

compared to the recovered and circum-neutral lakes (Figure 8a; ANOVA, F = 16.24, p <

0.001). However, species turnover was relatively high in all lakes (time corrected species

turnover range: 0.14 – 2.4 species per year), suggesting that species composition is

relatively unstable (Figure 8b).

Species turnover is influenced by the number of species in a lake because the

calculation included species richness in the denominator. Therefore, we also assessed

compositional change as net species change, or the difference between the numbers of

species gained and lost in a time interval. In individual acid lakes, there was a tendency

to gain species between 1972-73 and 2005 (Figure 9a). Approximately half of the

recovered lakes gained at least one species with improved water quality, although one

lake (Frood Lake) actually lost 5 species (Figure 9b). Circum-neutral lakes tended to lose

species through time with 75% of the lakes losing one to four species (Figure 9c). Acid lakes have statistically higher net species change compared to recovered and circum- neutral lakes (ANOVA, F = 9.91, p < 0.01). There are no significant relationships

between net species change with chemical recovery in terms of change in H+ 28

concentration (linear regression; acid lakes: r2 = 0.02, p = 0.62; recovered lakes: r2 = 0.10, p = 0.26; circum-neutral lakes: r2 = 0.01, p = 0.85).

The first two axes of a principal component analysis on 1972-73 zooplankton

species composition explained 60% of the variation in the species composition across

Killarney lakes (Figure 10). Zooplankton community composition of the three lake

categories was separated along the first axis, which explained 45% of the variation. The first axis appears to be driven by pH (r2 = 0.44, p < 0.01). The lakes cluster along the axis according to lake category with acid lakes grouped on one end of the axis and circum-neutral lakes on the other end of the axis. Recovered lakes (which all had pH

below 6.0 in 1972-73) were scattered throughout the gradient (Figure 10a). Communities in acid lakes (low PCA axis 1 score) were dominated by L. minutus (Figure 10b).

Circum-neutral lakes (high PCA axis 1 score) were dominated by D. birgei, M. edax,

Bosmina spp., Epischura lacustris, D. retrocurva, D. b. thomasi, T. extensus, and D.

mendotae.

The first two axes of a principal component analysis on 2005 zooplankton species

composition explained 56% of the variation in species composition across lakes (Figure

11). Zooplankton community composition of the three lake categories was separated along the first axis, which explained 41% of the variation. As with the 1972-73 data, the first axis was driven by pH (r2 = 0.59, p < 0.01) (Figure 11a). Communities in acid lakes

(low PCA axis 1 score) are dominated by Leptodiaptomus minutus as noted in the 1972-

73 PCA (Figure 11b). Circum-neutral lakes were dominated mostly by acid-sensitive species with some more acid-tolerant species – D. b. thomasi, D. mendotae, D. retrocurva, Skistodiaptomus oregonensis, M. edax, D. birgei, and T. extensus. 29

A comparison of PCA axis 1 scores between 1972-73 and 2005 revealed shifts in

zooplankton community composition for all recovered lakes (Figure 12). The majority of

the lakes shifted positively along the first axis towards community composition more

similar to that found in the circum-neutral lakes, providing evidence of biological recovery. Three of the recovered lakes (Evangeline, Logboom, and Little Sheguiandah) have axis 1 scores in 2005 that are indistinguishable from circum-neutral lakes. These lakes were moderately acidified in the 1970s, having pH 5.9, 5.3, and 5.0, respectively in

1972-73. The largest community shift observed, as expressed by PCA axis 1 score, was in Norway Lake. This lake was severely damage by acidification and since then has chemically recovered to a pH of 5.7 from 4.7 in 1972-73. Interestingly, two of the circum-neutral lakes, Helen and La Cloche lakes, shifted to community structures more similar to acid lakes in 2005. These lakes have recently been invaded by the predatory zooplankton, Bythotrephes longimanus (Table 2).

Potential drivers of biological recovery

Linear regression was used to examine the relationship between chemical

recovery (H+ change) and change in community structure and composition indices

(Figure 13a-f). The change in species richness between 1972-73 and 2005 was positively

correlated with the change in H+ during that time, although the relationship was weak

(Linear regression, r2 = 0.11, p = 0.02) (Figure 13a). Although Cook’s distance showed

no effects of leverage with values < 1 (Quinn and Keough 2002) the regression was run

excluding Gail Lake which was the most acidic lake in the survey – all relationships were

maintained indicating that Gail Lake did not influence trends. There was no significant

relationship between H+ change and changes in other community indices (diversity, 30

evenness (Evar), total crustacean zooplankton abundance, species turnover, and change in

PCA axis 1 score between 1972-73 and 2005 (Figure 13b-f).

Multiple regression was used to compare the drivers between 1972-73 and 2005 using the same set of response variables (species richness, diversity, evenness, and total abundance) and similar predictor variables (elevation, maximum depth, pH, and total phosphorus). In both 1972-73 and 2005, the most parsimonious models to explain species richness had positive associations of species richness with pH, but in 1972-73 zooplankton richness was also negatively related to lakes with higher elevation (Table 5 and 6). Both elevation and pH were important predictors of species diversity in 1972-73

(Table 5), whereas in 2005, pH was the only significant driver (Table 6). Evenness, Evar, in 1972-73 was not associated with any predictor variables (Table 5). However, in 2005, communities were less even in low pH and high elevation lakes (Table 6). Total zooplankton abundance was low in high elevation and deep lakes in 1972-73, whereas in

2005, abundance was primarily driven total phosphorus (Table 5 and 6).

Evaluation of spatial and environmental factors

The sphere of influence model (least connected model) was the best model to assess the role of spatial and local environmental factors on zooplankton communities in

1972-73 and 2005 as it had the lowest residual variation (45% for 1972-73, 55% for

2005) compared to Delaunay triangulation (55% for 1972-73, 56% for 2005), Gabriel

(48% for 1972-73, 53% for 2005), and relative neighbour (52% for 1972-73, 52% for

2005) models. In 1972-73, elevation, pH, and maximum depth were significant (using forward selection) and were included in the model along with several spatial variables.

Spatial variables can be thought of as a gradient based on their eigenvalue. Spatial 31 variables with large eigenvalues (soi 2, soi 5, and soi 8) represent broad (regional) scale processes, whereas spatial factors with small eigenvalues (soi 11) suggest smaller (local) processes (Figure 14a). Intermediate values represent intermediate spatial processes.

Individual variance partitioning indicated that all environmental variables were significant with pH explaining the most variation (13.8%, p < 0.01) compared to maximum depth (6.9%, p < 0.02), and elevation (6.5%, p < 0.01) for 1972-73 analyses.

In 2005, forward selection indicated that all environmental variables (elevation, pH, maximum depth, and total phosphorus) were significant, along with several broad scale

(soi 5, soi 8) scale spatial variables. pH explained the largest amount of the individual variance (32.7%, p < 0.01) followed by elevation (13%, p < 0.01), total phosphorus

(10.3%, p < 0.01), and maximum depth (8.2%, p = 0.01).

For the RDA of 1972-73 zooplankton communities, both the first (λ = .32, F =

16.7) and all canonical axes together (trace = .52, F = 4.9) were significant (Monte Carlo test: p < 0.01). In 1972-73 the zooplankton communities were structured by a combination of environmental as well as regional (soi 2, soi 5, and soi 8) and local (soi

11) spatial factors (Figure 14a). In comparison, 2005 zooplankton communities were structured by environmental and regional spatial factors (Figure 14b). Both the first (λ =

.31, F = 16.4) and all canonical axes together (trace = .50, F = 5.2) were significant

(Monte Carlo test: p < 0.01) for the 2005 RDA.

The variation partitioning for 1972-73 showed that the variation in zooplankton community composition in Killarney Park lakes was equally explained by purely spatial

(20%) and environmental (18%) variables (Figure 15). Spatially-structured environmental variables explained an additional 17% of the variation with 45% 32 unexplained. Pure spatial and environmental variation were both significant (p < 0.01), however, there was no significant difference between environmental and spatial variation

(p = 0.71). Interestingly, in 2005 zooplankton community variation was explained mostly by purely environmental variables accounting for 31% of the variation, whereas purely spatial and spatially-structured environmental variables explained only 11% and

3% of the variance, respectively (Figure 15). Pure environmental variation was significantly different from zero (p < 0.01), whereas purely spatial variation was marginally significant (p = 0.06). Environmental variables marginally explained more variation than spatial variables in 2005 communities (p = 0.07).

TABLE 1. Selected physical characteristics of the 45 Killarney Park study lakes. Lake surface areas from Sprules (1975). Zmax = lake maximum depth, Secchi = secchi disk transparency.

Lake Latitude (N) Longitude (W) Area (ha) Zmax (m) Elevation (m) Secchi (m) Acid 46° 02' 81° 26' 17.7 29.8 272 8.5 A.Y. Jackson 46° 01' 81° 23' 6.1 10.1 197 8.3 Bell 46° 07' 81° 12' 281.3 27.2 223 3.6 Bodina 46° 06' 81° 29' 30.3 2.7 210 1.8 Boundary 46° 07' 81° 18' 74.1 8.5 223 8.0 Carlyle 46° 03' 81° 17' 166.9 13.1 218 3.6 Charlton 46° 08' 81° 43' 218.9 17.3 200 4.6 Clearsilver 46° 07' 81° 15' 23.9 14.5 222 11.2 David 46° 08' 81° 18' 325.8 22.6 243 4.9 deLamorandiere 46° 02' 81° 27' 5.3 7.6 294 7.6 Evangeline 46° 08' 81° 51' 384.9 20.6 205 3.6 Fish 46° 09' 81° 23' 90.7 8.1 212 3.8 Freeland 46° 02' 81° 22' 32.2 2.4 191 2.4 Frood 46° 07' 81° 43' 191.8 17.6 196 4.4 Gail 46° 09' 81° 22' 16.6 16.0 252 15.5 Gem 46° 09' 81° 26' 14.2 19.6 214 3.5 George 46° 01' 81° 24' 147.9 39.2 185 8.0 Great Mountain 46° 09' 81° 21' 191.6 36.9 224 7.1 Helen 46° 06' 81° 33' 68.2 39.0 185 6.6 Howry 46° 09' 81° 28' 101.9 28.0 201 4.5 Ishmael 46° 06' 81° 35' 65.4 17.5 182 6.8 Johnnie 46° 05' 81° 14' 395.5 32.4 200 4.3 Kakakise 46° 03' 81° 19' 118.9 23.5 190 6.9 Killarney 46° 04' 81° 21' 357.2 56.9 199 13.6 La Cloche 46° 07' 82° 04' 1088.3 33.9 192 3.8 Little Mountain 46° 08' 81° 21' 20.0 25.6 232 15.3 Little Sheguiandah 46° 01' 81° 23' 5.0 2.5 184 2.5 33 TABLE 1 (continued).

Lake Latitude (N) Longitude (W) Area (ha) Zmax (m) Elevation (m) Secchi (m) Little Superior 46° 04' 81° 19' 12.1 34.7 276 18.5 Logboom 46° 07' 81° 14' 6.0 6.1 220 1.4 Low 46° 06' 81° 33' 28.6 28.4 182 6.8a Lumsden 46° 01' 81° 25' 21.5 23.3 213 9.0 Muriel 46° 03' 81° 26' 22.6 13.4 194 9.8 Nellie 46° 08' 81° 31' 238.3 49.0 267 21.6 Norway 46° 05' 81° 18' 59.6 34.4 198 8.5 O.S.A. 46° 03' 81° 23' 291.4 39.8 205 20.0 Partridge 46° 05' 81° 18' 9.2 16.8 203 10.0 Proulx 46° 04' 81° 19' 10.5 29.1 257 22.0 Roque 46° 01' 81° 28' 3.4 8.6 298 6.5 Ruth-Roy 46° 05' 81° 15' 46.1 19.3 217 13.7 Shingwak 46° 04' 81° 19' 4.6 22.1 282 22.1 Solomon 46° 01' 81° 27' 5.2 3.6 292 3.6 Terry 46° 03' 81° 17' 10.1 8.0 212 4.8 Threenarrows 46° 06' 81° 26' 947.9 35.9 197 6.1 Turbid 46° 06' 81° 11' 14.8 9.4 217 5.4 Whiskeyjack 46° 05' 81° 17' 13.8 43.4 276 28.0 a data from Kalyniuk (2005) 34 TABLE 2. Selected chemical and biological characteristics of the 45 Killarney Park study lakes. Lake water sampled as 5 m tube composite samples during July and August of 2005. Lake status defined as described in methods; acid = pH always < 6, recovered = pH increased from < 6 to > 6, circum-neutral = pH always > 6. Cond = Conductivity. TP = average total phosphorus from two samples taken at the same time. DOC = dissolved organic carbon, Ca = calcium, chl. a = chlorophyll a . Bytho and Fish = presence/absence of Bythotrephes and Fish respectively, 0 = absence, 1 = presence. Fish data from Snucins and Gunn (1998). Cond TP DOC Ca chl. a Lake Lake Status pH Bytho Fish (µS/cm) (µg/L) (mg/L) (mg/L) (μg/L) Acid Acid 5.3 18.3 2.6 1.6 1.1 0.05 0 0 A.Y. Jackson Recovered 6.3 19.8 6.1 3.3 1.4 0.91 0 1 Bell Recovered 6.6 25.5 5.1 5.8 1.8 1.35 1a 1 Bodina Circum-neutral 6.9 - 19.4 10.0 3.2 7.01 0 1 Boundary Recovered 6.0 19.5 4.2 1.4 1.1 0.74 0 1 Carlyle Recovered 6.4 22.6 10.2 3.6 1.6 1.35 1 1 Charlton Circum-neutral 7.3 62.2 6.0 4.3 5.0 2.28 0 1 Clearsilver Acid 5.2 18.7 1.8 0.9 0.7 0.04 1a 0 David Acid 5.5 17.5 3.1 1.5 1.1 2.35 0 1 deLamorandiere Acid 5.1 - 5.3 1.4 1.0 0.79 0 0 Evangeline Recovered 7.0 46.0 16.8 6.1 3.2 3.89 0 1 Fish Recovered 6.5 25.7 6.1 4.4 1.9 1.98 0 1 Freeland Acid 5.7 21.6 7.2 3.4 1.6 1.33 0 1 Frood Recovered 7.3 61.4 11.2 4.4 4.9 1.85 0 1 Gail Acid 4.6 20.8 2.8 0.5 0.6 0.15 0 0 Gem Circum-neutral 6.8 27.3 8.1 5.2 2.5 2.31 0 1 George Recovered 6.6 24.9 3.5 1.9 1.8 0.92 1a 1 Great Mountain Recovered 6.0 20.1 12.9 2.6 1.4 0.37 0 1 Helen Circum-neutral 7.1 26.8b 3.6 3.4 2.6 1.06 1 1 Howry Circum-neutral 6.9 28.8 7.2 4.8 2.7 1.51 0 1 Ishmael Circum-neutral 7.0 29.2b 4.8 4.0 2.8 1.60 0 1 35 TABLE 2 (continued). Cond TP DOC Ca chl. a Lake Lake Status pH Bytho Fish (µS/cm) (µg/L) (mg/L) (mg/L) (μg/L) Johnnie Recovered 6.2 23.6 4.5 3.5 1.7 1.39 0 1 Kakakise Recovered 6.8 32.2 2.6 3.0 2.4 0.46 1a 1 Killarney Acid 5.4 23.6 2.5 0.5 1.4 0.08 0 1 La Cloche Circum-neutral 7.3 42.8 7.3 5.5 3.4 2.25 1 1 Little Mountain Acid 5.2 22.8 1.8 0.1 1.3 0.06 0 0 Little Sheguiandah Recovered 7.0 20.2 9.2 5.2 1.4 1.68 0 1 Little Superior Acid 4.4 - 2.0 0.1 0.7 0.35 0 0 Logboom Recovered 6.1 25.1 11.3 5.0 1.8 2.64 0 1 Low Circum-neutral 7.8 68.0b 6.6 3.3 8.8 0.79 1 1 Lumsden Acid 5.6 17.4 3.3 1.2 1.1 0.09 0 0 Muriel Acid 5.8 - 3.1 0.9 1.8 0.43 0 1 Nellie Acid 4.7 30.7 1.2 0.3 1.3 0.10 0 0 Norway Acid 5.7 21.6 1.7 1.0 1.3 0.20 0 1 O.S.A. Acid 5.1 28.0 2.6 0.2 1.7 0.05 0 0 Partridge Recovered 6.2 25.0 2.6 2.0 1.8 0.48 0 1 Proulx Acid 4.7 - 2.4 0.1 1.1 0.15 0 0 Roque Acid 5.1 - 5.7 1.9 1.2 1.08 0 0 Ruth-Roy Acid 5.1 22.1 2.4 0.1 1.0 0.06 0 0 Shingwak Acid 4.8 - 2.0 0.1 0.9 0.08 0 0 Solomon Acid 5.0 - 8.9 2.0 1.1 0.84 0 0 Terry Acid 5.8 20.6 8.8 4.5 1.4 1.04 0 1 Threenarrows Recovered 6.3 - 4.2 3.4 1.8 1.30 0 1 Turbid Acid 5.4 23.5 5.8 6.0 1.3 0.92 0 1 Whiskeyjack Acid 4.6 27.2 1.3 0.2 0.4 0.11 0 0 a previous sighting; b data from 2006 survey (J.A. Shead, unpublished data) 36 37

TABLE 3. Spearman's rank correlation coefficients (ρ) of year of study with recovery metrics in the 45 studied Killarney lakes in the three different lake categories. Evar = evenness. Species Total Zooplankton Diversity E Richness var Abundance Acid Lakes Acid -0.95* -0.60+-0.60+ -0.20+ Clearsilver -0.32+-1.00* -0.80† -1.00* David -0.95* -0.40+ -0.40+ -0.40+ deLamorandiere -0.40+ -0.20+ -0.40+-0.80† Freeland -0.40+-0.80† -0.00+ -0.40+ Gail -0.95* -0.40+ -0.40+ -1.00* Killarney -0.32+-0.80† -0.40+ -1.00* Little Mountain -0.40+ -0.40+ -1.00* -0.20+ Little Superior 0.40 -0.20+ -0.80† -0.40+ Lumsden -0.32+-0.00+-0.80† -0.80† Muriel -0.60+-1.00* -0.60+ -0.20+ Nellie -0.00+ -0.60+ -0.20+ -0.40+ Norway -0.32+-0.20+ -0.80† -0.40+ OSA -0.40+-0.40+ -0.40+ -0.40+ Proulx -0.95* -0.40+ -0.80† -0.40+ Roque -0.40+ -0.80† -1.00* -0.40+ Ruthroy -0.80† -0.80† -0.40+ -0.20+ Shingwak -0.80† -0.80† -0.40+-0.00+ Solomon -0.21+ -0.40+ -0.20+-0.40+ Terry -0.63+-0.40+-0.20+-0.60+ Turbid -0.40+-0.60+ -0.40+-0.60+ Whiskeyjack -0.63+-0.20+ -1.00* -0.20+ Recovered Lakes AY Jackson -0.00+-0.40+-0.40+ -0.80† Bell -0.11+-0.80† -0.20+ -0.40+ Boundary -0.63+-0.60+ -0.40+ -0.40+ Carlyle -0.40+ -0.20+-0.00+ -0.40+ Evangeline -0.63+-1.00* -0.60+-0.80† Fish -0.63+ -0.40+ -0.40+ -0.40+ Frood -0.80† -0.40+-0.40+-0.80† George -0.40+-0.40+-0.600-0.60+ Great Mountain -0.40+-1.00* -0.40+ -0.80† Johnnie -0.32+-0.40+-0.40+ -0.20+ Kakakise -0.20+-0.20+-0.40+-0.40+ Little Sheguindah -0.20+ -0.80+ -0.40+ -0.40+ 38

TABLE 3. (continued) Species Total Zooplankton Diversity E Richness var Abundance Logboom -0.32+ -0.40+ -0.40+-0.80† Partridge -0.32+-0.40+-0.40+-0.40+ Threenarrows -0.40+-0.80† -0.20+ -0.40+ Circum-neutral Lakes Bodina -0.63+ -0.80† -0.20+ -0.20+ Charlton -0.32+ -0.40+ -0.20+-1.00* Gem -0.80† -1.00* -0.80† -0.80† Helen -0.95* -0.20+ -0.40+-0.00+ Howry -0.21+-0.00+-0.20+-0.80† Ishmael -0.77+-0.80† -0.80† -0.20+ La Cloche -0.60+ -0.80† -0.40+ -0.40+ Low -0.63+-0.40+ -0.20+-0.40+ * p<0.05, † p<.10 39

Table 4. Species names associated with ordination species code names. Arranged in alphabetical order of ordination code name. Species Ordination Code Acroperus harpae ACO HAR Alona sp. ALONA SP Bosmina spp. BOS Bythotrephes longimanus BYTHO Ceriodaphnia sp. CERIODAP Chydorus sphaericus CHY SP Cyclops scutifer CYC SCU Acanthocyclops robustus CYC VER Daphnia (Daphnia) ambigua D. AMB Daphnia (Daphnia) catawba D. CAT Daphnia (Hyalodaphnia) dubia D. DUB Daphnia (Hyalodaphnia) mendotae D. GAL Daphnia (Hyalodaphnia) longiremis D. LON Daphnia (Daphnia) parvula D. PAR Daphnia (Daphnia) pulex and pulicaria D. PP Daphnia (Daphnia) retrocurva D. RET Daphnia (Daphnia) schodleri D. SCH Daphnia sp. D. SP Leptodiaptomus minutus DIA MIN Skistodiaptomus oregonensis DIA ORE Skistodiaptomus reighardi DIA REI Leptodiaptomus sicilis DIA SIC Diaphanosoma birgei DIA SPP Diacyclops bicuspidatus thomasi DIA THO Epischura lacustris EPI LAC Holopedium gibberum HOL GIB Latona setifera LAT SET Leydigia leydigi LEY LEY Limnocalanus macrurus LIM MAC Macrocyclops albidus MAC ALB Mesocyclops edax MES EDA Orthocyclops modestus ORT MOD Polyphemus pediculus POL PED Senecella calanoides SEN CAL Tropocyclops extensus TRO EXT TABLE 5. Multiple regression of 1972-73 crustacean zooplankton species richness, diversity, evenness, and total abundance with predictor variables in all study lakes (n = 45). Predictor variables include pH, maximum depth, elevation, and total phosphorus. AIC = Akaike's Information Criterion, TP = total phosphorus Partial Adjusted Mallows Response Variable 2 AIC F -ratio p -value Variable Coefficent correlation t -value p -value r Cp coefficent

Species Richness 0.60 2.47 85.14 33.98 < 0.001*** Elevation -0.31 -0.40 -2.83 < 0.01** pH 0.60 0.65 5.53 < 0.001***

Species Diverstiy 0.55 3.40 -142.29 19.24 < 0.001*** Elevation -0.36 -0.45 -3.19 < 0.01** Max Depth -0.19 -0.28 -1.88 0.07 pH 0.50 0.56 4.37 < 0.001***

Evennness, Evar 0.01 -0.76 -121.39 0.24 0.63 Max Depth 0.07 0.07 0.49 0.63

Total Zooplankton 0.14 2.57 -89.46 4.72 0.01* Elevation -0.31 -0.33 -2.26 0.02* Abundance Max Depth -0.30 -0.32 -2.17 0.03* * p <0.05, ** p <0.01, *** p <0.001 40 TABLE 6. Multiple regression of 2005 crustacean zooplankton species richness, diversity, evenness, and total abundance with predictor variables in all study lakes (n = 45). Predictor variables include pH, maximum depth, elevation, and total phosphorus, dissolved organic carbon, and change in pH (measured as change in H+ concentration). AIC = Akaike's Information Criterion, TP = total phosphorus. Partial Adjusted Mallows Response Variable 2 AIC F -ratio p -value Variable Coefficent correlation t -value p -value r Cp coefficent

Species Richness 0.31 -0.51 75.81 20.88 < 0.001*** pH 0.57 0.57 4.57 < 0.001 ***

Species Diverstiy 0.54 0.08 -79.15 53.26 < 0.001 *** pH 0.74 0.74 7.30 < 0.001 ***

Evennness, Evar 0.38 1.11 -109.25 14.21 < 0.001*** Elevation -0.29 -0.24 -1.61 0.12 pH 0.39 0.31 2.15 0.04*

Total Zooplankton 0.38 1.73 -67.12 27.84 < 0.001 *** log TP 0.63 0.63 5.28 < 0.001 *** Abundance * p <0.05, ** p <0.01, *** p <0.001 41 42

Killarney Provincial Park

Canada

U.S.A.

46°05’N

3 km N Orthoquartzite bedrock

81°25’N

16 Acid 2 14 r = 0.92 Recovered p < 0.001 12 Circum-neutral 10

) 1972-73 to 2005 8 5 6 4

] change (x10 2 +

[H 0 -2 0 2 4 6 8 10121416

[H+] (x105) in 1972-73

FIGURE 2. Linear regression between H+ concentration in 1972-73 (i.e., acidity) and chemical recovery (the change in H+ concentration between 1972-73 and 2005) for 45 Killarney Park lakes classified into three lake groups based on water quality improvements. Regressions are significant at p < 0.05. 44 Biological Threshold

Sensitive Species Lost Sensitive Species Return ? 12

6 1972-73 2005

Number of Lakes Number 4

0 3.6 4.0 4.4 4.8 5.2 5.6 6.0 6.4 6.8 7.2 7.6

FIGURE 3. The frequency of pH in the 45 Killarney Park lakes in 1972-73 (black bars) and 2005 (white bars). pH of 6 is considered a biological threshold for crustacean zooplankton in which below a pH of 6 you observe losses of acid sensitive species (Keller et al. 2002). 45

100 Acid Recovered 80 Circum-neutral

40 Percent Lakes

0 1972-73 1990 2000 2005

Year

FIGURE 4. The frequency (percent lakes) for 45 Killarney Park lakes from 1972-73, 1990, 2000, and 2005 classified into 3 lake groups based on water quality improvements. 46

14 8 (a) (b) 12 10 6 8 4 6 4 2 Species Richness 2 Species Diversity 0 0 1970 1980 1990 2000 2010 1970 1980 1990 2000 2010 Year Year

0.6 60 (c) (d) 0.5 0.4 40

var 0.3 E 0.2 20 0.1

0 Total Abundance. (#/L) 0 1970 1980 1990 2000 2010 1970 1980 1990 2000 2010 Year Year

Acid Circum-neutral Recovered

FIGURE 5. Long-term changes in average (a) species richness, (b) species diversity,

(c) evenness (Evar), (d) and total abundance of crustacean zooplankton (number per liter) for 45 Killarney Park lakes from 1972-73, 1990, 2000, 2005 classified into 3 lake categories based on water quality improvements – acid (n=22), recovered (n=15), and circum-neutral (n=8). Error bars represent standard error. (a) Acid Lakes (n = 22) 47 120 100 80 60 40 % of Lakes 20 0

(b) Recovered Lakes (n = 15) 100 80 60 40

% of Lakes 20 0

%of Lakes 20 0 1972-73 1990 2000 2005 Year Bosmina spp. Diacyclops bicuspidatus thomasi Chydorus sphaericus Diaphanosoma birgei Daphnia mendotae Holopedium gibberum Daphnia longiremis Leptodiaptomus siciloides Leptodiaptomus minutus Polyphemus pediculus Skistodiaptomus oregonensis Mesocyclops edax Daphnia retrocurva Tropocyclops extensus

5 Number of Species Number

20 (b) Recovered Lakes 15 1972-73 10 2005 5 Number of Species Number

20 (c) Circum-neutral Lakes 15

5 Number of Species Number

0 25 50 75 100 % Lakes Occupied

FIGURE 7. Crustacean zooplankton distribution across Killarney Park lakes represented as the percentage of lakes occupied for 1972-73 and 2005. Lakes were divided into three categories: a) acid, b) recovered, and c) circum- neutral. 49

70 (a) 60 a 50

40 b

30 b 20 % Species Turnover 10

0 Acid Recovered Circum-neutral

2.0 (b) a 1.6

1.2 b

b 0.8

0.4

% Time Corrected Species Turnover 0 Acid Recovered Circum-neutral

FIGURE 8. Average a) zooplankton species turnover and b) time corrected species turnover between 1972-73 and 2005 calculated for 45 Killarney Park lakes grouped into 3 categories based on water quality improvements. Error bars represent standard error. 8 50 (a) Acid Lakes

0 # of Species -4

-8 8 (b) Recovered Lakes Net Species 4 Gain

0 # of Species -4 Net Species Loss -8 8 (c) Circum-neutral Lakes

0 # of Species -4

-8 Increased change in H+ concentration

Figure 9. Net species change for zooplankton communities (# appeared - # disappeared) between 1972-73 and 2005 for 45 Killarney Park lakes grouped into 3 categories based on water quality improvements. Lakes are arranged in increasing order of chemical recovery (i.e., H+ concentration). Grey bars indicate a net species gain. Black bars indicate a net species loss. 51 1.5 (a)

Acid Recovered Circum-neutral = 0.15) 2 -1.0 λ -1.0 1.5

0.6 (b) BOS PCA Axis 2 ( MACRO AL POL PED DIA REI D. PP HOL GIB CERIODAP D. PAR D. SCH

D. AMB DIA SPP ORT MOD TRO EXT LIM MAC DIA MIN D. RET D. LON MES EDA SEN CAL

DIA ORE EPI LAC D. GAL

DIA THO

-0.8 -1.0 1.0

PCA Axis 1 (λ1 = 0.45)

FIGURE 10. Principal components analysis of 1972-73 zooplankton species abundances. Shown are a) sample and b) species. Species with short arrows were removed to reduce crowding. Species names can be found in Table 4. 52 1.0 (a)

Acid Recovered Circum-neutral = 0.15) 2 λ -0.8 -1.5 1.5

1.0 (b)

PCA Axis 2 ( DIA THO

D. GAL

DIA ORE D. RET EPI LAC D. LON SEN CAL DIA SIC D. SP MES EDA DIA SPP D. DUB CYC VER BYTHO D. CAT CHY SP ACO HAR TRO EXT DIA REI DIA MIN POL PED D. AMB ORT MOD CERIODAP LEY LEY

BOS HOL GIB -0.4 -1.0 1.0 PCA Axis 1 (λ1 = 0.41)

0 -2 -1 0 1 2 2005 PCA Axis 1 -1

-2

1972-73 PCA Axis 1

Acid Circum-neutral Recovered 1:1 Line

FIGURE 12. Shift in zooplankton community composition. Comparison of 1972-73 and 2005 PCA axis 1 scores for crustacean zooplankton communities of 45 Killarney Park lakes. Lake categories are based on water quality improvements. 1:1 indicates no change in community composition. 54 8 4 (a) (b) 4 2 0 0 R2 = 0.11 -4 p = 0.02 -2 Species Richness Species Diversity

Δ -8

Δ -4 -2 0 2 4 6 8 10 12 14 16 -2 0 2 4 6 8 10 12 14 16

1.2 140 (c) (d) 0.8 70 0.4 var

E 0 0

Δ -0.4 -70 -0.8 Total Abundance

-1.2 Δ -140 -2 0 2 4 6 8 10 12 14 16 -2 0 2 4 6 8 10 12 14 16

100 3 (e) (f) 75 1.5 50 0

25 PCA Axis 1 -1.5 Δ 0

% Species Turnover -3 -2 0 2 4 6 8 10 12 14 16 -2 0 2 4 6 8 10 12 14 16 [H+] Change (x105) [H+] Change (x105)

Acid Circum-neutral Recovered

FIGURE 13. Relationship between chemical recovery (measured as change in H+ concentration, [H+]) and change (Δ) in a) species richness, b) species diversity, c) evenness (Evar), d) total zooplankton abundance, e) percent (%) species turnover, and f) PCA axis 1 between 1972-73 and 2005 for 45 Killarney park lakes. Lake categories based on water quality improvements. Only significant (p<0.05) linear regressions are shown. 0.8 (a) 0.6 (b) POL PED soi 8 soi 5 HOL GIB soi 8 ACO HAR ALONA SP soi 5 D. CAT HOL GIB TRO EXT BOS CHY SP D. PP POL PED D. AMB D. PAR TP D. AMB Elev CYC VER BOS =.12) =0.09) 2 2

λ CERIODP D. CAT λ EPI LAC DIA SPP ORT MOD DIA MIN MES EDA SEN CAL D. SP DIAP SP D. RET DIA MIN D. LON TRO EXT RDA Axis 2 ( Elev RDA Axis 2 ( EPI LAC pH MES EDA soi 11 DIA ORE D. RET D. LON Zmax D. GAL soi 2 D. GAL Zmax DIA THO DIA THO

pH DIA ORE 0.6 -0.8 - -1.0 1.0 1.0 -1.0 RDA Axis 1 (λ1 =.31) RDA Axis 1 (λ1 = .29)

FIGURE 14. Redundancy analysis of zooplankton species abundances and environmental conditions for a) 1972-73 and b) 2005. Environmental variables are represented by the large arrows and species by the small arrows. Species with short arrows were removed to reduce crowding. Species names can be found in Table 4. TP = total phosphorus, Zmax = maximum depth,

Elev = elevation. Spatial variables are abbreviated e.g. soi5 = sphere of influence variable 5. 55 56

1972-73

env. sp-env.

Year sp. unexplained

2005

0% 20% 40% 60% 80% 100%

Variation Explained

FIGURE 15. Partitioning of variation in zooplankton communities in Killarney Park lakes in 1972-73 and 2005. The variation in species abundances is explained by purely environmental (env), purely spatial (sp), spatially structured environmental (sp-env) variables with the remaining being the residual variation (unexplained). 57

CHAPTER 4: DISCUSSION

Chemical Recovery

Our survey of 45 lakes in Killarney Park revealed an increase in lake water pH in

the majority of the lakes since the early 1970s. Interestingly, lakes that were most acidic

in 1972-73 showed the largest increase in H+ concentration through time. These lakes

and others in the Sudbury region have experienced gradual increases in pH throughout

the past three decades as SO2 emissions from metal smelters in and around Sudbury have

been reduced (Keller and Pitblado 1986, Keller et al. 2003). Despite improvements in

lake water pH, 22 lakes in Killarney Park are still acidic (pH < 6.0) with six of those still severely acidified (pH < 5.0). Paleolimnological inferences of several Killarney Park

lakes have indicated that pH levels in some lakes (Acid, Terry, Johnnie, Carlyle, George,

Bell, Kakakise, Ishmael, Helen, and Low) have returned to pre-industrial levels (Keller et

al. 2003). Our results support these findings; most of these lakes had lake water pH > 6.0

in our 2005 survey. Interestingly, Acid Lake, which has a current pH of 5.3, had a

diatom-inferred historical pH of ~5.2. Although we do not have paleolimnological

records for all our study lakes, the information suggests that some of the lakes were

historically acidic and may not experience increases in lake water pH as acid deposition

decreases. This group of historically-acid lakes include Ruth-Roy Lake, which has a

current pH 5.1, had a diatom inferred historical pH of 4.9 (Smol et al. 1998). Although

some of these lakes are naturally acidic, they were further acidified due to anthropogenic

emissions and as a result have shown chemical recovery with emission reductions and

were included in the analyses. While sulphur dioxide emission reductions to current

levels have enabled the recovery of many of the study lakes, 49% of the historically 58 acidified lakes remain below pH 6, the generally accepted threshold for biological recovery (Keller et al. 2002). On a larger scale, Jeffries et al. (2000) suggested that at current emissions, ~ 12% (76 000 of 646 000) of southeastern Canada’s lakes will remain acidic. As a result, it is evident that acid-damaged lakes both in Killarney Park and the rest of southeastern Canada will require further emission reductions before we may see recovery at larger scales.

Biological Recovery

Despite major water quality improvements in many lakes, there was limited zooplankton recovery especially in severely damaged lakes that are slower to recover.

There was considerable variation among the community metrics used to indicate recovery status; some showed evidence of biological recovery, while others did not. Univariate metrics revealed minimal evidence of biological recovery. Species richness increased through time in acid lakes but not for recovered or circum-neutral lakes. The other metrics, evenness, diversity, and total zooplankton abundance, revealed no evidence of biological recovery. When investigated independently, individual lakes did show limited evidence of biological recovery for the various metrics and indicated large variation among lakes and lake types. However, these results must be interpreted with caution because of low statistical power with only four sample dates in time. In accordance with

Yan et al. (1996b), we found that species richness is a better indicator of recovery than diversity, evenness, and total crustacean abundance.

We expected that improvements in water quality in lakes would be associated with an increased distribution of zooplankton, especially acid-sensitive species, across the landscape. However, we found no evidence for regional level recovery. In other words, 59

distribution patterns of zooplankton did not change between 1972-73 and 2005 in acid or

recovering lakes. This is especially true in acid lakes, many of which are still dominated

by a single species, L. minutus. This suggests that there may be a barrier that is preventing the colonization of these lakes, despite the high regional pool of species (31

species). A significant shift towards species occupying fewer lakes in the landscape (i.e.

becoming more rare), however, was observed for circum-neutral lakes. This suggests

that these lakes are not static and that potentially there are regional forces acting on them.

There is growing evidence that large-scale stressors, including climate change (Schindler

2001), declines in calcium (Keller et al. 2001b), and invasive species (Strecker et al.

2006) are impacting lakes on the Canadian Shield, including Killarney Park. This

suggests that these stressors may be changing zooplankton communities of circum-

neutral lakes, thereby altering or distorting target communities for biological recovery.

Consequently, pre-acidification communities may never exist again given enough

ongoing changes to the regional species pool and environmental conditions.

Species turnover is a measure of community composition variability. We

expected high compositional variability in lakes experiencing biological recovery (i.e. the

colonization of species) compared to acid and neutral lakes. Unexpectedly, species turnover was highest in acid lakes compared to the other lake categories. Because species turnover calculations are influenced by the total number of species present in a lake, lower species richness of acid lakes resulted in high percent species turnover even though the average number of appearances and disappearances of species was similar in acid (4.2) and recovered (4.6) lakes. The species turnover observed in Killarney Park lakes (< 2% per year) is much lower compared to eight Dorset lakes with apparent 60

species turnover rate averaging 16% per year over a 12 year period (Arnott et al. 1999).

As estimates of species turnover decrease with time between sampling periods

(Magnuson et al. 1994), our estimates of species turnover must be taken with caution.

Our estimates were based on a time interval (33 years) much larger than the annual

species turnover reported for the Dorset lakes. As a result, we likely missed a substantial

number of species immigrations and extinctions over that long time period. Furthermore,

the error was likely inflated with potential rare species being missed due to one-time

sampling. When we examined the change of zooplankton through time as net species

change, we found that the majority of acid lakes gained species which supports our

increasing trend in average species richness through time. Recovered and circum-neutral

lakes showed a mixture of gains and losses with no significant relationship between the

net species gain with change in H+ concentration through time. This data is not conclusive evidence of biological recovery as we would have expected to see a net species gain in most recovered lakes. However, it does show that since 1972-73 over half

of the lakes (67%) have had a net gain of at least one zooplankton species.

Keller et al. (1992a) suggested that increases in the abundance of acid-sensitive

species and declines in the abundance of acid-tolerant species are good indicators of recovery of aquatic biota from acidification. We observed decreases in the dominance of acid-tolerant species (e.g., L. minutus and H. gibberum) and increases in acid-sensitive species (e.g., D. mendotae, D. longiremis, T. extensus, and D. b. thomasi) in Killarney

Park lakes through time, providing evidence for some degree of biological recovery.

Because univariate metrics ignore species interrelationships, Yan et al. (1996b)

recommended the use of multivariate techniques that incorporate the relative abundances 61

of taxa. As with other studies (Arnott et al. 2001, Frost et al. 2006), we observed stronger

evidence of biological recovery when zooplankton community composition was examined through time. Zooplankton communities in the majority of our study lakes have become more similar to those of circum-neutral lakes, with some recovered lake communities being indistinguishable from those of circum-neutral ones. There was no significant difference in PCA axis 1 scores between recovered and circum-neutral lakes for summer 2005 zooplankton communities (Tukey p > 0.05). Using a smaller subset of our 45 study lakes, Holt and Yan (2003) indicated there was little change between 1990 and 2000. Our results are not comparable to those of Holt and Yan (2003) because of the different methods used. We do show that between 1972-73 and 2005 that the majority of lakes have shifted towards circum-neutral compositions indicating substantial recovery during this time period.

Barriers to Biological Recovery

Despite some evidence of biological recovery in lakes that have chemically

recovered and in some acid lakes, for the most part, biological recovery is not complete.

This may be attributed to several potential factors including abiotic conditions, biological

resistance, colonization barriers, and additional stressors complicating lake recovery.

Biological recovery can be hindered by many abiotic factors. Although acid

sensitive species have returned to those lakes that have recovered from being moderately

acidified, chemical recovery in Killarney Park is incomplete. In 2005, there were still 22

Killarney Park lakes below the biological threshold of pH 6.0, with 6 lakes of those still

severely acidified (pH<5.0). However, it should be noted that some of these lakes were

not circum-neutral prior to industrial activities and as a result may never reach pH 6.0. 62

Other studies have suggested that delayed biological recovery is at least partially

attributable to the lack of chemical recovery of some lakes (e.g., Arnott et al. 2001,

Jeffries et al. 2003). We observed that lakes with low amounts of chemical recovery (H+

concentration) had minimal increases in species richness and in some instances species

loss for those lakes that remained acidic (Figure 13a). We also showed that pH was a

main driver for the structure and composition in 1972-73 (species richness, species

diversity) and 2005 (species richness, species diversity, evenness). These results are in agreement with the well known positive relationship between zooplankton species richness and pH (Marmorek and Korman 1993). As a result, biological recovery will continue to lag until more chemical recovery is seen within Killarney Park. This has been suggested for other parts of the world including Europe (e.g., Skjelkvåle et al.

2003).

In many lakes in Canada, the United States, and Europe, decreases in sulphate

concentrations have been partially counterbalanced by decreases in base cation

concentrations resulting in little change in pH or alkalinity (Keller et al. 2003, Jeffries et

al. 2003). Decreases in base cations, in particular calcium, may have important biological implications for lakes that continue to recover from acidification. Calcium not only mitigates the toxicity of metals and acidity, it is an essential element for daphnids and other organism with calcified exoskeletons that have high calcium demands (Alstad et al. 1999, Jeziorski and Yan 2006). Calcium is also known to influence the composition

(Hessen et al. 1995) and size structure of zooplankton communities (Tessier and

Horowitz 1990). It is unlikely that calcium concentrations in Killarney Park are impeding recovery as concentrations ranged from 0.4 to 8.8 mg/L in 2005, generally 63

above the lower threshold of calcium limitation of 0.52 mg/L (Alstad et al. 1999). This

suggests that acid-sensitive and calcium dependent species (e.g., D. mendotae) are not

directly inhibited to colonize lakes due to calcium limitation.

2- Along with reductions in the concentrations of SO4 and base cations in water, decreases in metal concentrations have been observed in the Sudbury region (e.g., Keller

et al. 1999, Keller et al. 2003). Metals related to emissions from Sudbury, Cu and Ni, have impacts on lakes close to smelters (Keller et al. 1992b). With reduction of emissions, Cu and Ni surface water concentrations in Killarney Park lakes in 2005 range from 0.3-1.5 μg/L and 0.5-12.8 μg/L, respectively. Although there is still traces of

Sudbury’s emission effects on these lakes in terms of elevated Ni levels (Keller et al.

2003), they are currently below the water quality guidelines for Cu (5 μg/L) and Ni (25

μg/L) set to protect aquatic biota (Ministry of the Environment and Energy 1994). These

concentrations are higher than those in 42 reference lakes in Dorset, ON, with

concentrations always <1 μg/L (Keller et al. 2003). Despite this, as 2005 concentrations are below water quality guidelines, Cu and Ni are probably not hindering biological recovery. Metals associated with watershed leaching as a result of acidification, Zn and

Al, have shown significant declines in several Killarney lakes that have been monitored annually from 1981 to 2001 (Keller et al. 2003). Keller et al. (2003) indicates that this reduction is attributable to decreases in lake acidity and leaching from the watershed. In

2005, all survey lakes had Zn surface water concentrations below the provincial standards of 30 μg/L (Ministry of the Environment and Energy 1994). Paleolimnological techniques showed that Al concentrations for some chemically recovered lakes are now similar to diatom-inferred pre-industrial levels (Keller et al. 2003). In 2005 Al 64

concentrations in some survey lakes were still elevated (range: 9-544 μg/L) with 15

acidic lakes with concentrations above 100 μg/L. However, elevated Al concentrations

are only a concern for lakes that are still acidic meaning that it is not distinguishable

whether Al concentration or pH is causing the lack of recovery.

The relative importance of nitrogen deposition may increase following reductions

in SO2 not only in North America but in Europe as well (Jeffries et al. 2003, Skjelkvåle et

al. 2003). Despite an observed decrease in sulphate deposition, nitrate deposition in

eastern North America has changed little during the 1990s and in some instances have

increased (Jeffries et al. 2003). In Killarney Park, surface water concentrations of

sulphate are approaching levels found in reference lakes around Dorset, Ontario (Keller

et al. 2003). This suggests that lakes in these regions are now primarily affected by long-

range transport of S (Keller et al. 2003). Little is known about nitrate concentrations in

surface waters of Killarney Park. To date, Killarney Park has shown no evidence of N

saturation leading to acidification (Keller et al. 2003). Historical data for nitrate

concentrations in our survey lakes does not exist. However, redundancy analysis of 2005 crustacean zooplankton abundances with an extensive series of environmental factors

indicated that nitrate was not significant in describing community composition. This

would suggest that nitrate is not impeding biological recovery in Killarney Park.

Species interactions may prevent or delay biological recovery. Provided abiotic

conditions are favorable, the successful re-colonization of acid-sensitive species may be

hindered by interaction with invertebrate predators as well as existing acid-structured

zooplankton communities. Local extinction of fish as a result of acidification can cause

invertebrate predators (e.g. Chaoborus, notonectids, and corixids) that are normally 65

controlled by fish predation to thrive (Eriksson et al. 1980). These invertebrate predators

have shown to have significant impacts on zooplankton (Yan et al. 1991, Arnott et al.

2006) including preventing the successful invasion of zooplankton species (Arnott and

Vanni 1993). Current historical fish data are lacking for Killarney Park lakes. Data from

the mid-1990s (Snucins and Gunn 1998) shows presence of both planktivous and

piscivorous fish in all recovered and circum-neutral lakes. Of the 22 acidic lakes in this

study, 15 were fishless. We compared zooplankton recovery (measured as change in

PCA axis 1 scores from 1972-73 to 2005) between fish and fishless lakes and found a

significant difference (p < 0.01) with more recovery in lakes with fish present. Similarly,

significantly more recovery was observed in just acid lakes with fish than without fish (p

< 0.01). Agreeing with Holt and Yan (2003), it would be impossible to distinguish the role of invertebrate predation from pH as all fishless lakes were acidic.

The locally-adapted resident zooplankton community may impede the successful

colonization of acid-sensitive species, even when pH has reached the pH 6.0 threshold

(Keller and Yan 1998). Binks et al. (2005) showed three acid-sensitive colonist species

D. b. thomasi, S. oregonensis, and M. edax (to a lesser extent) were not impacted by pH

but experienced reduced abundances when in the presence of the resident zooplankton

community. It has been suggested that acid-sensitive species may be superior

competitors to acid-tolerant species provided pH is high enough (Fischer et al. 2001). As

a result, we would expect that as lake pH increases and successful colonization of these

acid-sensitive competitive species occurs, acid tolerant species would decrease in

abundance. In 2005, we observed the return of acid-sensitive species in many lakes and

in some cases, they dominated lakes across the landscape. In particular, acid-sensitive 66

species D. mendotae, D. longiremis, T. extensus, and D. b. thomasi all showed increased dominance in Killarney Park lakes through time. Similarly, we observed that between

1972-73 and 2005 that the majority of acidic and recovered lakes gained at least one species. This suggests that biological resistance by the acid-structured zooplankton community may not be preventing the recovery of lakes that have shown chemical recovery.

We found little evidence to suggest that dispersal was limiting the recovery of

crustacean zooplankton in our study lakes. In 2005, environmental factors explained

more of the variation in zooplankton community composition compared to the spatial

configuration of the lakes (31% vs. 11%). This suggests that overland dispersal was not

limiting the recovery process and that the current zooplankton community is limited more

by local environmental conditions. In contrast, spatial and environmental factors

contributed almost equally to explaining the variation in the 1972-73 zooplankton community with 20% and 18% of the variation explained, respectively. This suggests

that the spatial arrangement of the lakes was as important as the environmental conditions

of the lakes in determining species composition when the lakes acidified. These results

suggest that at the onset of lake acidification, the ability of resistant colonists to get to

lakes was equally as important as the decline in acid-sensitive species in determining how

species composition responded to the new environmental conditions. The reduced

importance of the spatial configuration of lakes in the landscape as lakes recover suggests

that dispersal limitation is less severe. One hypothesis for this is that lakes may be re-

colonized from within lake sources (i.e., spatial refuges within the lake or resting stages

historically deposited in the sediments) as environmental conditions improve. Binks et 67

al. (2005) observed that diverse assemblages of crustacean zooplankton hatched from the

sediments of historically acidified lakes that had experienced chemical but not biological recovery, suggesting that recovery was not limited by dispersal from the egg bank. It is possible that recent colonists in Killarney Park lakes may be dispersing from resting egg banks within individual lakes, and are therefore not constrained by overland dispersal vectors. However, Pollard et al. (2003) demonstrated that recent Daphnia colonists in a recovering Sudbury lake did not originate from the local egg bank, but probably from a nearby lake. Although our results suggest that within lake dispersal may be important for recovery in Killarney lakes, further investigation of the relative importance of colonist sources is needed.

We observed changes in the zooplankton species composition in our subset of

circum-neutral lakes. This suggests that additional regional stressors such as invasive species and climate change could influence the continued and future recovery of

Killarney Park lakes and others within the region. Some of our circum-neutral lakes lost species and experienced shifts in zooplankton community composition from 1972-73 to

2005. For example, Helen and La Cloche lakes shifted towards zooplankton composition more typical of an acidic lake. Observed changes included a decrease in the abundance of acid-sensitive species S. oregonensis, D. retrocurva, M. edax, D. b. thomasi and an increase in the abundance of L. minutus. This shift may have been caused by the recent invasion of the exotic predatory zooplankton, Bythotrephes longimanus. Bythotrephes has been shown to have large impacts on zooplankton communities in circum-neutral lakes near Dorset, in particular acid-sensitive Daphnia species (Strecker et al. 2006). Not limited to impacting circum-neutral lakes, Bythotrephes has been shown to drastically 68

alter the zooplankton community biomass and abundance of lakes recovering from

acidification (Strecker et al. 2005). Given that it is a very successful overland disperser

via human vectors and its rapid spread to in-land lakes in Ontario (MacIsaac et al. 2004),

we expect the future recovery of Killarney Park lakes may be affected as a result.

The implications of climate change on aquatic ecosystems are large (Schindler

2001). Climate driven stress including climate change, acidification, and increased UV-B

penetration are linked through very complex interactions (Schindler et al. 1996, Yan et al.

1996a). These are likely to affect lake recovery processes. Water quality improvement

and biological recovery have also been temporarily reversed in the Sudbury region due to

short-term climatic driven events such as re-acidification from drought (Arnott et al.

2001, Yan et al. 1996a). It is unlikely that climate-driven re-acidification has hindered the recovery of Killarney Park lakes to date as the majority of lakes have shown chemical recovery from 1972-73 to 2005. Those lakes that are susceptible are small and shallow, with high flushing rates, extensive wetlands and base-poor soils (Arnott et al. 2001). Of the 45 studied lakes, 6 acid lakes had maximum depths less than 10 meters and ranged in size from 3.4 ha to 32 ha (Table 1). These 6 acidic lakes have high flushing rates (range:

0.26-0.92 years) making them susceptible to potential drought-re-acidification. Although we have no evidence to suggest that this has impacted their chemical recovery in the past, given current climate change scenarios drought-driven episodes of re-acidification may become more important in some Killarney Park lakes in the future.

Snucins and Gunn (2000) documented climate-driven changes in thermal

structure in a subset of 86 small Killarney Park lakes. They showed increases in surface

water temperatures in warm years while the volume of cold water decreased in clear lakes 69

compared to colored lakes. MacLennan (2007) found similar results that included

increases in surface and epilimnetic temperatures in a warm year (2005) compared to a

cold year (2006) for 20 Killarney Park lakes. The variation in zooplankton between years

was best explained by epilimnetic temperatures causing zooplankton communities in

warmer years to shift in compositions to resemble more acidic communities (MacLennan

2007). Given that the majority of acid lakes in Killarney Park are very clear lakes (some

with Secchi discs transparencies > 20 m) the potential increase in water temperature may

result in the loss of cold water zooplankton species. This provides another possible

scenario in which climate-driven processes may limit the recovery of zooplankton.

Unexpected decreases in species richness, net loss of species, and shifts in species

dominance in circum-neutral lakes may also be a result of the complex climatic

interactions and other additional stressors such as invading species. As the most common

method used to assess biological recovery is to compare damaged communities to

circum-neutral ones, such effects will have implications. Since recovery targets are based on circum-neutral communities, changes in them will be like chasing a moving target causing distorted recovery assessments. Furthermore, as the effects of these stressors become more pronounced, it is possible that reference community compositions may never be seen again on a regional scale. Consequently, it becomes more important to continue monitoring lakes from disturbances such as acidification using long-term monitoring on an annual basis but also assessing recovery in terms of multiple stressors.

Implications

We found strongest evidence of biological recovery in terms of shifts in

zooplankton communities in chemically recovered lakes, and to a certain extent acid 70 lakes, from a damaged state to one typical of circum-neutral lakes. However, our results must be interpreted with some caution. Our data set was limited in terms of the frequency and time of sampling and lack of historical water chemistry for variables other than pH. Although our data record spans more than three decades, there were only four sampling points in time. While we can assess general trends, it is more difficult to distinguish mechanisms that are driving the observed changes. Although single samples can provide insights into the general characteristics of the lake, a single zooplankton sample at one point in the summer is not representative of the actual lake community that exists and that upwards to 50% of the ice-free species pool in a lake can be missed

(Arnott et al. 1998). Olden et al. (2006) suggest that over a broad environmental gradient, such as our pH gradient, a single year estimate of zooplankton community composition compared among different lakes over time may be adequate. Ideally, lakes would have been sampled bi-weekly every year during open water conditions for both zooplankton and chemistry since the emission reductions were put into place. However, surveys of this magnitude are logistically and financially difficult to conduct. We lacked extensive chemical data from the historical surveys. As a result, our description of the mechanisms driving community structure was limited to basic physical and chemical characteristics. An RDA of the 2005 zooplankton community with an extensive series of physical and chemical variables indicated the environmental variables used in our analyses were variables that explained the most variation.

This study adds to the growing body of evidence in the literature demonstrating that with reductions in SO2, improvements in water quality occur followed eventually by biological recovery of lakes. Although we reported strong evidence of chemical 71

recovery, biological recovery was modest with acidic lakes experiencing limited recovery

of biota. Changing abiotic conditions and new barriers to biological recovery such as

climate change and the arrival of invasive species may threaten the future recovery of

Killarney Park lakes.

One of the goals of emission reductions is the recovery of aquatic ecosystems.

However, to date, recovery is not complete. In southeastern Canada, of the 646 000 estimated acid-sensitive lakes present in the region, approximately 76 000 lakes will remain chemically damaged unless more stringent reductions are implemented (Jeffries et

al. 2000). In Killarney Park, 22 of the 45 study lakes remain acidic (pH < 6.0).

Modeling of 3 Killarney Park lakes under different emission reductions scenarios suggest that an additional 75% reduction in emissions are required for acid-sensitive lakes to

recover, with some lakes requiring more than 50 years to stabilize (Larssen et al. 2003).

It is clear that continued monitoring and assessment of recovery in Killarney lakes is

needed. Initiation of a long-term monitoring program in Killarney is essential to develop

a database of various chemical and biological variables that can be used to examine

regional responses of the various stressors impacting freshwater lakes with other long-

term databases in other regions such as Dorset, Ontario and the Experimental Lakes Area

in northwestern Ontario.

Since multiple stressors are likely to impact the state of circum-neutral lakes,

assessment of recovery by comparing recovered to circum-neutral communities will

become more difficult for managers. This suggests that as these stressors impact aquatic systems new recovery targets may need to be set. Continued monitoring of the chemical 72 and biological components of lakes will allow these changes to be tracked and sufficient recovery goals to be set.

Killarney Park continues to be a model system for other acid-damaged regions in

North America and Europe (Gunn and S. Sandøy 2003), as well as Asia (Larssen et al.

2006). The amount of biological recovery reported here and in previous studies show promise for the future recovery of aquatic systems as a result of emission reductions. 73

SUMMARY

1) The majority of the lakes in Killarney Park have increased in pH since the early 1970s.

Those lakes that were most acidic in 1972-73 showed the largest increase in H+

concentration. Despite increases in lake water pH, 22 study lakes in Killarney Park

were still acidic (pH <6.0) in 2005 with six of those still severely acidified (pH < 5.0).

2) There was considerable variation among the community metrics used to indicate

recovery status. Evidence of biological recovery using univariate metrics included the

increase in zooplankton species richness in acidic lakes since 1972-73, the net gain of

species in the majority of acidic and recovered lakes, and increase in the dominance of

acid-sensitive species such as D. menodate, D. b. thomasi, and T. extensus. Univariate

metrics also showed evidence of limited biological recovery including the decrease in

species richness of recovered lakes to levels similar to that of 1972-73 and a lack of

significant increase in the distribution of zooplankton in acidic or recovered lakes over

time. The strongest evidence of biological recovery was seen using multivariate

metrics examining shifts in community compositions through time. Between 1972-73

and 2005, the majority of lakes have shifted from a damaged crustacean zooplankton

community to one more typical of circum-neutral lakes with some recovered lakes

being indistinguishable from circum-neutral lakes.

3) pH appears to be the main driver of crustacean zooplankton community composition

and structure. Other environmental variables such as elevation, total phosphorus and

maximum depth also contributed significantly in describing zooplankton community

composition and structure. 74

4) Abiotic factors, in particular pH, appear to be important barriers to biological

recovery. We suggest that biological recovery will continue to be delayed until more

chemical recovery is seen in Killarney Park.

5) Biological resistance from acid-structured resident communities does not appear to be

limiting the recovery of zooplankton communities. Lakes with fish showed greater

biological recovery compared to fishless lakes suggesting that invertebrate predators

may be impeding biological recovery. However, these results are not conclusive and

should be taken with caution, as we are not able to distinguish if the presence of fish

or pH is driving this observation.

6) Little evidence was found to suggest that dispersal was limiting the recovery of

crustacean zooplankton communities in our study lakes. In 2005, environmental

factors explained more variation in zooplankton community composition than the

spatial configuration of the lakes, suggesting that dispersal was not limiting biological

recovery. Instead, the summer 2005 zooplankton community appears to be limited

more by current environmental conditions. In contrast, at the onset of lake

acidification, pH and the spatial configuration of the lakes were equally important in

determining species composition. This implies that when the lakes initially acidified,

zooplankton composition was shaped by the declining lake water pH and the ability of

zooplankton to disperse from lake to lake. These results suggest that within lake

dispersal (i.e., the emergence of zooplankton from historically deposited resting eggs)

may be important for recovery of Killarney lakes. Further investigation of the relative

importance of colonist sources is needed. 75

7) The recent invasion of Bythotrephes in some Killarney Park lakes may be responsible

for shifts in community composition in some circum-neutral lakes towards that more

typical of acidic lakes. With the invasion of Bythotrephes, the acid-sensitive species

S. oregonensis, D. retrocurva, M. edax, D. b. thomasi decreased in abundance. The

future recovery of Killarney Park lakes may be affected with further invasion by this

species.

8) No conclusive evidence was found for the effect of large-scale climate-driven events

on the chemical and biological recovery of Killarney Park lakes to date. However, the

potential effects of climate change are not to be ignored and future monitoring and

research are merited. 76

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Zar, J.H. 1999. Biostatistical anlaysis. Prentice Hall, Upper Saddle River, NJ, USA. APPENDIX 1. Selected chemical characteristics of the 45 Killarney Park study lakes. Lake water sampled as 5 m tube composite samples during July and August of 2005. Lake status Lake status defined as described in methods; A = acid (pH always < 6), R = recovered (pH increased from < 6 to > 6), N = circum-neutral (pH always > 6). TKN = Total Kjeldahl

Nitrogen, Si = silicon (reactive silicate), Na = sodium, SO4 = sulphate, Cl = chloride, K = potassium, Al = aluminum, Cu = copper, Fe = iron, Ni = nickel, Zn = zinc.

Lake Lake pH TKN Si Na SO4 Cl K Al Cu Fe Ni Zn Status (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (µg/L) (µg/L) (µg/L) (µg/L) (µg/L) Acid A 5.3 0.11 0.96 0.46 5.55 0.35 0.21 112.0 0.6 49.0 5.2 14.8 A.Y. Jackson R 6.3 0.27 0.28 0.72 6.55 0.34 0.32 16.6 1.1 9.0 2.1 3.5 Bell R 6.6 0.43 0.66 0.92 6.75 0.56 0.53 40.0 2.1 25.4 5.9 10.5 Bodina N 6.9 0.16 0.02 1.12 6.40 0.43 0.42 19.4 1.3 49.8 1.8 2.3 Boundary R 6.0 0.17 0.34 0.47 5.35 0.33 0.35 21.4 1.0 42.0 4.4 6.7 Carlyle R 6.4 0.27 1.14 0.89 6.50 0.55 0.33 33.1 1.8 24.6 3.5 8.9 Charlton N 7.3 0.27 0.40 3.27 9.50 4.76 0.56 13.0 2.1 19.8 3.5 0.7 Clearsilver A 5.2 0.09 0.78 0.40 5.55 0.26 0.24 138.0 1.1 55.6 9.9 24.5 David A 5.5 0.16 0.62 0.49 5.30 0.56 0.53 42.7 1.7 24.8 6.4 7.5 deLamorandiere A 5.1 0.21 0.06 0.46 5.80 0.22 0.22 72.6 1.2 86.1 4.4 12.7 Evangeline R 7.0 0.33 0.24 2.34 5.15 2.87 0.51 13.8 1.0 48.4 0.8 0.2 Fish R 6.5 0.19 0.68 0.79 5.60 1.17 1.49 16.9 1.9 30.2 3.0 3.4 Freeland A 5.7 0.24 0.02 0.51 6.80 0.08 0.17 35.2 0.7 90.8 3.7 6.9 Frood R 7.3 0.26 0.36 3.31 9.45 4.87 0.57 12.5 3.1 18.1 4.8 0.9 Gail A 4.6 0.25 0.20 0.33 5.35 0.29 1.14 268.0 1.5 42.1 10.0 14.3 Gem N 6.8 0.30 0.68 0.85 5.35 0.47 0.45 28.6 1.5 48.9 3.6 1.8 George R 6.6 0.15 1.02 0.68 6.70 0.44 0.33 21.6 1.1 11.3 3.2 7.4 Great Mountain R 6.0 0.26 0.66 0.64 5.95 0.33 0.28 23.6 1.0 14.5 3.6 4.9 Helen N 7.1 0.18 1.14 0.80 6.25 0.31 0.38 20.2 0.8 15.0 1.7 0.7 Howry N 6.9 0.59 0.94 0.90 5.85 0.48 0.43 32.0 1.6 20.1 4.3 2.6 86 APPENDIX 1 (continued).

Lake Lake pH TKN Si Na SO4 Cl K Al Cu Fe Ni Zn Status (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (µg/L) (µg/L) (µg/L) (µg/L) (µg/L) Ishmael N 7.0 0.25 0.80 0.85 6.05 0.33 0.41 12.5 0.6 14.3 1.7 0.7 Johnnie R 6.2 0.12 0.58 0.75 6.80 0.37 0.38 62.3 2.5 40.9 7.0 9.7 Kakakise R 6.8 0.39 0.60 0.80 6.65 0.63 0.33 9.2 1.0 8.3 1.7 1.5 Killarney A 5.4 0.09 1.10 0.59 7.20 0.31 0.29 101.0 2.2 21.4 7.2 27.4 La Cloche N 7.3 0.27 0.52 1.47 5.95 1.52 0.50 9.8 1.2 16.5 1.8 0.9 Little Mountain A 5.2 0.37 1.04 0.54 6.70 0.33 0.26 135.0 1.0 27.2 9.9 11.9 Little Sheguiandah R 7.0 0.36 0.46 0.75 3.90 0.15 0.11 30.4 1.2 27.4 0.5 2.8 Little Superior A 4.4 0.10 0.14 0.30 8.60 0.40 0.21 544.0 3.5 67.7 11.8 23.3 Logboom R 6.1 0.47 0.56 0.78 6.60 0.36 0.41 50.9 2.9 187.0 6.9 12.0 Low N 7.8 0.20 0.44 1.38 7.80 1.49 0.59 9.7 1.0 6.6 0.7 0.0 Lumsden A 5.6 0.14 1.10 0.49 5.45 0.30 0.21 85.2 0.3 46.1 3.7 13.3 Muriel A 5.8 0.15 0.14 0.64 7.60 0.41 0.29 45.9 1.1 23.4 5.3 11.1 Nellie A 4.7 0.08 0.36 0.47 8.20 0.46 0.25 412.0 2.1 29.0 8.6 19.5 Norway A 5.7 0.18 1.24 0.69 6.85 0.53 0.34 62.6 1.3 17.3 6.8 11.8 O.S.A. A 5.1 0.06 0.02 0.60 7.85 0.41 0.29 116.0 1.3 10.2 5.3 19.7 Partridge R 6.2 0.18 0.42 0.69 7.85 0.34 0.32 28.8 1.2 4.4 5.1 8.9 Proulx A 4.7 0.14 0.36 0.46 8.45 0.34 0.30 434.0 2.6 28.5 11.3 20.6 Roque A 5.1 0.22 1.02 0.49 6.00 0.06 0.18 102.0 0.4 53.8 4.1 16.5 Ruth-Roy A 5.1 0.07 0.50 0.47 6.35 0.32 0.19 166.0 1.2 29.1 11.2 19.7 Shingwak A 4.8 0.09 0.80 0.40 6.50 0.27 0.21 238.0 1.5 24.3 8.4 19.7 Solomon A 5.0 0.31 0.02 0.63 6.35 0.25 0.30 82.8 0.5 98.3 4.3 13.0 Terry A 5.8 0.31 0.78 0.68 5.60 0.27 0.27 122.0 1.0 167.0 4.9 9.4 Threenarrows R 6.3 0.11 1.42 0.78 6.55 0.34 0.38 19.9 1.1 12.5 3.7 3.8 Turbid A 5.4 0.36 0.34 0.81 6.80 3.04 4.07 111.0 2.3 76.9 12.8 13.9 Whiskeyjack A 4.6 0.09 0.16 0.41 8.10 0.29 0.23 367.0 3.8 29.3 11.1 17.8 87 APPENDIX 2. Water chemistry protocols used in the analyses of water samples. For more information contact the Ministry of Environment Laboratory Services Branch in Rexdale, Ontario. DOC = dissolved organic carbon, Ca = calcium, Mg = Magnesium, Na = sodium, K = potassium, TP = total phosphorus, Cl = Chloride, SO4 = sulphate, TKN = Total Kjeldahl Nitrogen, Al = Aluminum, Cu = Copper, Fe = Iron, Ni = Nickel, Zn = Zinc. Parameter Protocol Report Report Code The determination of pH and alkalinity in lakes, streams, pH and alkalinity DOCSI-E3042 groundwater and precipitation samples.

The determination of molybdate reactive silicates and dissolved DOC and Silica DOT-E3422 organic carbon in water and precipitation by colourimetry.

The determination of cations in precambrian shield waters by Atomic Ca, Mg, Na, and K DOFLAME-E3249 Absorption Spectrophotometry (AAS)

TP The determination of total phosphorus in water by colourimetry DOP-E3036

The determination of chloride and sulphate in surface water and wet Cl and SO4 DOIC-E3147 deposition samples by automated Ion Chromatography (IC).

The determination of Total Kjeldahl Nitrogen in surface water and TKN DTKN-E3424 precipitation by colourimetry.

The determination of conductivity in water and precipitation by Conductivity DOCOND-E3024 potentiometry.

The determination of metals in surface water by inductively coupled Al, Cu, Fe, Ni, Zn plasma - Atomic Emission Spectroscopy (ICP-AES) using ultrasonic MET-E3386 neubulization. 88 APPENDIX 3. Zooplankton species abundances (number per litre) for the 45 Killarney Survey Lakes in 1972-73 by Sprules (1975) Species Authority Acid A.Y. Jackson Bell Bodina Boundary Carlyle Acanthocyclops robustus a (Sars) Acantholeberis curvirostris (O.F. Müller) Acroperus harpae (Baird) Alona sp.b Baird Bosmina spp. c Baird 4.28 3.13 12.06 5.30 29.23 Bythotrephes longimanus Leydig Ceriodaphnia sp. b Dana 8.04 Chydorus sphaericus (O.F. Müller) Cyclops scutifer Sars 0.37 Daphnia (Daphnia) ambigua Scourfield 0.31 0.18 1.46 Daphnia (Daphnia) catawba Coker 0.03 Daphnia (Daphnia) parvula Fordyce Daphnia (Daphnia) pulex and pulicaria Leydig and Forbes 9.54 Daphnia (Daphnia) retrocurva Forbes 10.72 Daphnia (Daphnia) schodleri Sars 1.46 Daphnia (Hyalodaphnia) dubia Herrick Daphnia (Hyalodaphnia) longiremis Sars Daphnia (Hyalodaphnia) mendotae d Birge Daphnia sp. b O.F. Müller Diacyclops bicuspidatus thomasi (Forbes) 0.27 6.11 2.95 2.92 Diaphanosoma birgei e Kořínek 0.92 0.55 8.04 29.23 Drepanothrix dentata (Eurén) Epischura lacustris Forbes 1.34 Eucyclops elegans f (Herrick) Holopedium gibberum Zaddach 0.03 11.61 1.47 1.34 15.90 8.77 89 APPENDIX 3 (continued). Species Authority Acid A.Y. Jackson Bell Bodina Boundary Carlyle Ilyocryptus sp. Sars Latona setifera (O.F. Müller) Leptodiaptomus minutus (Sars) 3.08 7.64 7.56 71.03 74.54 Leptodiaptomus sicilis (Forbes) Leptodiaptomus siciloides (Lilljeborg) Leptopdiaptomus ashlandi (Marsh) Leydigia leydigi (Leydig) Limnocalanus macrurus Sars Macrocyclops albidus (Jurine) Macrothrix sp. Baird Mesocyclops americanus Dussart Mesocyclops edax (Forbes) 0.74 21.44 3.18 1.46 Ophryoxus gracilis Sars Orthocyclops modestus (Herrick) 0.31 Pleuroxus sp. Baird Polyphemus pediculus (Linnaeus) 0.18 Scapholeberis kingi Sars Senecella calanoides Juday Sida crystallina (O.F. Müller) Skistodiaptomus oregonensis (Lilljeborg) Skistodiaptomus reighardi (Marsh) 30.82 g Tropocyclops extensus (Kiefer) 0.18 42.87 a formerly Acanthocyclops vernalis complex b unable to identify, kept to genus level c pooled group. Includes Bosmina (Bosmina) liederi/freyi (De Melo and Hebert; in past referred to as Bosmina longirostris ), Eubosmina (Eubosmina) longispina (Leydig), Eubosmina (Neobosmina) tubicen (Brehm) 90 d formerly Daphnia galeata mendotae e Diaphanosoma birgei incorrectly referred to in past as Diaphanosoma leuchtenbergianum and Diaphanosoma brachyurum f formerly Eucyclops speratus g formerly Tropocyclops prasinus mexicanus 91 Species Charlton Clearsilver David deLamorandiere Evangeline Fish Freeland Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae Alona sp.b Bosmina spp. c 2.67 0.05 1.21 0.07 1.25 12.81 Bythotrephes longimanus Ceriodaphnia sp. b Chydorus sphaericus Cyclops scutifer Daphnia (Daphnia) ambigua 0.31 Daphnia (Daphnia) catawba Daphnia (Daphnia) parvula 1.42 Daphnia (Daphnia) pulex and pulicaria 0.61 Daphnia (Daphnia) retrocurva 1.46 0.07 0.31 Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis 1.21 0.23 Daphnia (Hyalodaphnia) mendotae d 0.10 Daphnia sp. b Diacyclops bicuspidatus thomasi 0.97 0.30 Diaphanosoma birgei e 3.16 0.07 7.78 0.13 Drepanothrix dentata Epischura lacustris 0.24 0.03 Eucyclops elegans f Holopedium gibberum 0.97 2.83 0.08 0.03 0.31 0.13 92 (continued) Species Charlton Clearsilver David deLamorandiere Evangeline Fish Freeland Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 6.07 4.79 14.15 5.76 0.33 16.19 0.54 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 4.61 0.79 2.18 Ophryoxus gracilis Orthocyclops modestus 2.35 Pleuroxus sp. Polyphemus pediculus 0.20 0.13 Scapholeberis kingi Senecella calanoides 0.24 0.03 Sida crystallina Skistopdiaptomus oregonensis 2.43 1.32 2.18 Skistopdiaptomus reighardi g Tropocyclops extensus 0.73 1.87 93 Species Frood Gail Gem George Great Mountain Helen Howry Ishmael Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae Alona sp.b Bosmina spp. c 1.52 9.01 4.01 1.85 1.18 2.15 1.57 2.84 Bythotrephes longimanus Ceriodaphnia sp. b 0.15 Chydorus sphaericus Cyclops scutifer Daphnia (Daphnia) ambigua 0.15 0.22 Daphnia (Daphnia) catawba Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva 0.61 0.77 Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis 1.21 0.08 Daphnia (Hyalodaphnia) mendotae d 0.15 1.56 0.41 0.74 0.26 Daphnia sp. b Diacyclops bicuspidatus thomasi 1.21 7.14 0.34 5.33 2.31 15.23 Diaphanosoma birgei e 1.67 3.79 0.41 0.66 0.52 Drepanothrix dentata Epischura lacustris 0.22 0.10 0.26 Eucyclops elegans f Holopedium gibberum 1.21 0.45 3.44 0.51 0.20 0.50 0.26 94 (continued) Species Frood Gail Gem George Great Mountain Helen Howry Ishmael Ilyocryptus sp. Latona setifera 0.15 Leptodiaptomus minutus 5.31 30.16 3.35 7.93 14.18 1.23 2.23 5.16 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 1.37 1.56 0.68 0.10 0.08 0.77 Ophryoxus gracilis Orthocyclops modestus 0.46 Pleuroxus sp. Polyphemus pediculus 0.13 Scapholeberis kingi Senecella calanoides 0.10 Sida crystallina Skistopdiaptomus oregonensis 0.46 0.22 0.41 0.08 0.26 Skistopdiaptomus reighardi g Tropocyclops extensus 0.15 0.22 0.10 95 Species Johnnie Kakakise Killarney La Cloche Little Mountain Little Sheguiandah Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae Alona sp.b Bosmina spp. c 0.87 0.89 1.29 2.77 3.37 6.69 Bythotrephes longimanus Ceriodaphnia sp. b Chydorus sphaericus Cyclops scutifer Daphnia (Daphnia) ambigua Daphnia (Daphnia) catawba 0.15 0.28 Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva 0.83 Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis 0.28 Daphnia (Hyalodaphnia) mendotae d 0.28 Daphnia sp. b Diacyclops bicuspidatus thomasi 0.15 8.32 4.44 Diaphanosoma birgei e 0.15 1.94 13.38 Drepanothrix dentata Epischura lacustris 0.28 Eucyclops elegans f Holopedium gibberum 2.33 0.15 0.28 7.94 96 (continued) Species Johnnie Kakakise Killarney La Cloche Little Mountain Little Sheguiandah Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 11.07 5.20 10.46 1.39 30.31 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus 0.28 Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 0.15 0.30 11.09 5.85 Ophryoxus gracilis Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus 0.15 0.12 Scapholeberis kingi Senecella calanoides Sida crystallina Skistodiaptomus oregonensis 0.55 Skistodiaptomus reighardi 7.94 g Tropocyclops extensus 4.71 97 Species Little Superior Logboom Low Lumsden Muriel Nellie Norway O.S.A. Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae Alona sp.b Bosmina spp. c 9.85 0.23 12.48 1.54 5.52 Bythotrephes longimanus Ceriodaphnia sp. b 0.11 Chydorus sphaericus Cyclops scutifer Daphnia (Daphnia) ambigua 0.11 Daphnia (Daphnia) catawba 0.94 Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria 1.03 Daphnia (Daphnia) retrocurva Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis Daphnia (Hyalodaphnia) mendotae d 0.46 Daphnia sp. b Diacyclops bicuspidatus thomasi 0.11 6.96 0.31 Diaphanosoma birgei e 0.11 0.23 Drepanothrix dentata Epischura lacustris 0.23 Eucyclops elegans f Holopedium gibberum 0.11 0.23 0.31 8.75 1.47 98 (continued) Species Little Superior Logboom Low Lumsden Muriel Nellie Norway O.S.A. Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 9.44 1.14 14.16 17.47 41.17 44.30 7.67 30.15 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus 0.11 Macrothrix sp. Mesocyclops americanus Mesocyclops edax 0.11 0.23 0.51 Ophryoxus gracilis Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus 0.11 0.31 0.51 0.45 Scapholeberis kingi Senecella calanoides Sida crystallina Skistodiaptomus oregonensis 1.16 Skistodiaptomus reighardi Tropocyclops extensus g 99 Species Partridge Proulx Roque Ruth-Roy Shingwak Solomon Terry Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae Alona sp.b Bosmina spp. c 0.55 Bythotrephes longimanus Ceriodaphnia sp. b Chydorus sphaericus Cyclops scutifer Daphnia (Daphnia) ambigua Daphnia (Daphnia) catawba 0.18 Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis Daphnia (Hyalodaphnia) mendotae d Daphnia sp. b Diacyclops bicuspidatus thomasi 1.10 2.57 Diaphanosoma birgei e 0.18 Drepanothrix dentata Epischura lacustris Eucyclops elegans f Holopedium gibberum 0.28 1.41 0.10 4.03 100 (continued) Species Partridge Proulx Roque Ruth-Roy Shingwak Solomon Terry Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 26.45 16.30 15.48 26.84 2.74 10.18 10.63 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 0.55 Ophryoxus gracilis Orthocyclops modestus 0.81 Pleuroxus sp. Polyphemus pediculus 0.28 0.28 Scapholeberis kingi Senecella calanoides Sida crystallina Skistodiaptomus oregonensis Skistodiaptomus reighardi Tropocyclops extensus g 101 Species Threenarrows Turbid Whiskeyjack Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae Alona sp.b Bosmina spp. c 1.24 1.20 Bythotrephes longimanus Ceriodaphnia sp. b Chydorus sphaericus Cyclops scutifer 0.14 Daphnia (Daphnia) ambigua 0.27 Daphnia (Daphnia) catawba 0.27 Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria 8.81 Daphnia (Daphnia) retrocurva 0.14 Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis Daphnia (Hyalodaphnia) mendotae d 0.96 Daphnia sp. b Diacyclops bicuspidatus thomasi 1.24 Diaphanosoma birgei e 0.96 Drepanothrix dentata Epischura lacustris Eucyclops elegans f Holopedium gibberum 1.10 15.22 102 (continued) Species Threenarrows Turbid Whiskeyjack Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 6.73 15.22 4.42 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 0.55 Ophryoxus gracilis Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus 0.14 Scapholeberis kingi Senecella calanoides Sida crystallina Skistodiaptomus oregonensis Skistodiaptomus reighardi g Tropocyclops extensus 0.14 103 APPENDIX 4. Zooplankton species abundances (number per litre) for the 45 Killarney Survey Lakes sampled in 1990 by Locke et al. (1994). Species Authority Acid A.Y. Jackson Bell Bodina Boundary Carlyle Acanthocyclops robustus a (Sars) Acantholeberis curvirostris (O.F. Müller) Acroperus harpae (Baird) 0.03 Alona sp.b Baird Bosmina spp. c Baird + h 0.11 0.35 0.21 37.82 2.07 Bythotrephes longimanus Leydig Ceriodaphnia sp. b Dana 0.01 1.28 Chydorus sphaericus (O.F. Müller) 0.01 Cyclops scutifer Sars Daphnia (Daphnia) ambigua Scourfield 0.04 + 0.10 Daphnia (Daphnia) catawba Coker 0.55 Daphnia (Daphnia) parvula Fordyce Daphnia (Daphnia) pulex and pulicaria Leydig and Forbes + + 0.03 Daphnia (Daphnia) retrocurva Forbes 0.19 0.36 Daphnia (Daphnia) schodleri Sars 0.03 Daphnia (Hyalodaphnia) dubia Herrick Daphnia (Hyalodaphnia) longiremis Sars Daphnia (Hyalodaphnia) mendotae d Birge 0.02 + Daphnia sp. b O.F. Müller Diacyclops bicuspidatus thomasi (Forbes) 0.02 0.30 Diaphanosoma birgei e Kořínek 5.47 4.87 3.63 0.03 2.37 Drepanothrix dentata (Eurén) Epischura lacustris Forbes + 0.03 Eucyclops elegans f (Herrick) Holopedium gibberum Zaddach 0.71 1.49 0.11 1.38 0.63 104 APPENDIX 4 (continued). Species Authority Acid A.Y. Jackson Bell Bodina Boundary Carlyle Ilyocryptus sp. Sars Latona setifera (O.F. Müller) Leptodiaptomus minutus (Sars) 3.44 2.18 3.74 0.04 17.01 3.33 Leptodiaptomus sicilis (Forbes) Leptodiaptomus siciloides (Lilljeborg) 5.12 Leptopdiaptomus ashlandi (Marsh) Leydigia leydigi (Leydig) Limnocalanus macrurus Sars Macrocyclops albidus (Jurine) Macrothrix sp. Baird Mesocyclops americanus Dussart Mesocyclops edax (Forbes) 0.02 0.07 1.08 0.09 0.50 0.27 Ophryoxus gracilis Sars 0.03 Orthocyclops modestus (Herrick) Pleuroxus sp. Baird Polyphemus pediculus (Linnaeus) 0.01 Scapholeberis kingi Sars Senecella calanoides Juday Sida crystallina (O.F. Müller) Skistodiaptomus oregonensis (Lilljeborg) 0.67 Skistodiaptomus reighardi (Marsh) 0.15 0.01 0.05 0.01 g Tropocyclops extensus (Kiefer) 0.04 0.43 3.67 0.80 a formerly Acanthocyclops vernalis complex b unable to identify, kept to genus level c pooled group. Includes Bosmina (Bosmina) liederi/freyi (De Melo and Hebert; in past referred to as Bosmina longirostris ), Eubosmina (Eubosmina) longispina (Leydig), Eubosmina (Neobosmina) tubicen (Brehm) 105 d formerly Daphnia galeata mendotae e Diaphanosoma birgei incorrectly referred to in past as Diaphanosoma leuchtenbergianum and Diaphanosoma brachyurum f formerly Eucyclops speratus g formerly Tropocyclops prasinus mexicanus h less than 0.01. 106 Species Charlton Clearsilver David deLamorandiere Evangeline Fish Freeland Acanthocyclops robustus a 0.16 Acantholeberis curvirostris + Acroperus harpae + Alona sp.b 0.02 + Bosmina spp. c 2.25 0.02 0.21 0.69 7.36 0.36 9.32 Bythotrephes longimanus Ceriodaphnia sp. b + 0.43 Chydorus sphaericus 0.08 0.03 0.04 0.75 0.02 Cyclops scutifer Daphnia (Daphnia) ambigua Daphnia (Daphnia) catawba Daphnia (Daphnia) parvula 0.02 Daphnia (Daphnia) pulex and pulicaria 0.05 Daphnia (Daphnia) retrocurva 6.48 0.85 0.43 Daphnia (Daphnia) schodleri 0.02 0.05 Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis Daphnia (Hyalodaphnia) mendotae d 0.84 0.37 Daphnia sp. b Diacyclops bicuspidatus thomasi Diaphanosoma birgei e 5.49 0.02 0.64 8.21 5.80 0.03 Drepanothrix dentata Epischura lacustris 0.30 0.25 Eucyclops elegans f Holopedium gibberum 0.57 0.02 1.43 0.04 4.80 107 (continued) Species Charlton Clearsilver David deLamorandiere Evangeline Fish Freeland Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 1.68 4.35 1.02 9.07 10.67 1.42 0.85 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 4.27 0.04 0.87 0.11 0.46 0.20 Ophryoxus gracilis Orthocyclops modestus 0.27 Pleuroxus sp. Polyphemus pediculus + + 0.02 Scapholeberis kingi + Senecella calanoides Sida crystallina 0.04 Skistodiaptomus oregonensis 9.30 1.07 5.05 0.04 Skistodiaptomus reighardi 0.18 0.01 g Tropocyclops extensus 0.46 1.21 0.02 0.20 108 Species Frood Gail Gem George Great Mountain Helen Howry Ishmael Acanthocyclops robustus a 0.04 0.04 Acantholeberis curvirostris Acroperus harpae Alona sp.b Bosmina spp. c 2.85 0.27 1.46 9.28 0.27 0.37 4.55 Bythotrephes longimanus Ceriodaphnia sp. b Chydorus sphaericus 0.01 0.04 Cyclops scutifer Daphnia (Daphnia) ambigua Daphnia (Daphnia) catawba Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva 2.15 0.16 Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis 0.08 0.13 1.25 Daphnia (Hyalodaphnia) mendotae d 0.60 0.80 0.69 0.83 6.90 Daphnia sp. b Diacyclops bicuspidatus thomasi 0.70 0.22 0.24 0.07 0.13 0.64 0.60 Diaphanosoma birgei e 2.90 3.49 1.50 0.58 0.59 0.39 Drepanothrix dentata Epischura lacustris 0.13 0.02 0.11 1.10 Eucyclops elegans f Holopedium gibberum 1.00 + 0.24 0.67 1.15 0.11 0.18 0.36 109 (continued) Species Frood Gail Gem George Great Mountain Helen Howry Ishmael Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 1.15 16.13 2.40 1.20 1.92 0.36 0.11 1.24 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus + Macrothrix sp. Mesocyclops americanus Mesocyclops edax 2.90 0.98 0.38 0.15 0.03 0.26 0.46 Ophryoxus gracilis + Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus 0.01 Scapholeberis kingi Senecella calanoides 0.06 Sida crystallina Skistodiaptomus oregonensis 1.00 0.93 0.14 0.32 0.18 Skistodiaptomus reighardi 0.02 + 0.08 0.09 g Tropocyclops extensus 0.70 0.04 0.03 0.02 0.18 110 Species Johnnie Kakakise Killarney La Cloche Little Mountain Little Sheguiandah Acanthocyclops robustus a 0.16 Acantholeberis curvirostris 0.04 Acroperus harpae Alona sp.b 0.21 Bosmina spp. c 0.26 1.17 4.89 1.12 0.00 28.80 Bythotrephes longimanus Ceriodaphnia sp. b 0.16 0.04 Chydorus sphaericus 0.16 0.00 Cyclops scutifer Daphnia (Daphnia) ambigua 0.02 0.06 Daphnia (Daphnia) catawba + Daphnia (Daphnia) parvula 0.05 Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva 0.16 Daphnia (Daphnia) schodleri 0.00 Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis + Daphnia (Hyalodaphnia) mendotae d 0.19 Daphnia sp. b Diacyclops bicuspidatus thomasi + 0.48 Diaphanosoma birgei e 1.60 0.37 0.96 0.00 7.73 Drepanothrix dentata 0.04 Epischura lacustris 0.19 Eucyclops elegans f Holopedium gibberum 0.38 1.39 0.80 0.16 0.53 111 (continued) Species Johnnie Kakakise Killarney La Cloche Little Mountain Little Sheguiandah Ilyocryptus sp. 0.00 Latona setifera Leptodiaptomus minutus 2.73 0.35 0.27 1.31 0.02 0.18 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 0.31 0.16 0.02 0.21 0.04 Ophryoxus gracilis 0.05 Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus ++ Scapholeberis kingi Senecella calanoides Sida crystallina 0.05 0.04 Skistodiaptomus oregonensis 0.21 Skistodiaptomus reighardi + 0.04 g Tropocyclops extensus 0.07 0.27 3.56 112 Species Little Superior Logboom Low Lumsden Muriel Nellie Norway O.S.A. Acanthocyclops robustus a + Acantholeberis curvirostris Acroperus harpae Alona sp.b + 0.06 Bosmina spp. c 0.01 4.57 0.26 0.03 3.09 0.02 1.85 0.75 Bythotrephes longimanus Ceriodaphnia sp. b 0.10 Chydorus sphaericus 0.01 + 0.02 0.03 Cyclops scutifer Daphnia (Daphnia) ambigua + 0.02 + Daphnia (Daphnia) catawba Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria 1.64 0.03 Daphnia (Daphnia) retrocurva Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis 0.01 + Daphnia (Hyalodaphnia) mendotae d + 1.19 0.05 Daphnia sp. b Diacyclops bicuspidatus thomasi + 0.23 0.03 0.02 Diaphanosoma birgei e + 0.10 0.09 0.12 0.19 Drepanothrix dentata Epischura lacustris 0.09 + Eucyclops elegans f Holopedium gibberum 0.01 0.02 0.02 8.61 0.02 0.39 113 (continued) Species Little Superior Logboom Low Lumsden Muriel Nellie Norway O.S.A. Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 2.24 0.01 0.45 1.87 0.91 0.52 0.44 0.40 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus + Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 0.23 0.30 0.02 0.26 0.00 Ophryoxus gracilis + Orthocyclops modestus 0.02 Pleuroxus sp. 0.02 Polyphemus pediculus 0.02 + 0.05 Scapholeberis kingi Senecella calanoides 0.06 Sida crystallina Skistodiaptomus oregonensis + + 0.09 Skistodiaptomus reighardi 0.01 0.07 + 0.00 g Tropocyclops extensus 0.90 0.03 114 Species Partridge Proulx Roque Ruth-Roy Shingwak Solomon Terry Acanthocyclops robustus a + Acantholeberis curvirostris Acroperus harpae Alona sp.b 0.07 Bosmina spp. c 0.04 + 0.11 0.53 1.78 Bythotrephes longimanus Ceriodaphnia sp. b Chydorus sphaericus + + + 0.07 Cyclops scutifer Daphnia (Daphnia) ambigua 1.42 Daphnia (Daphnia) catawba Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria 1.58 Daphnia (Daphnia) retrocurva 0.09 Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis 0.03 Daphnia (Hyalodaphnia) mendotae d 0.13 Daphnia sp. b Diacyclops bicuspidatus thomasi Diaphanosoma birgei e 0.13 + + 0.13 0.36 Drepanothrix dentata Epischura lacustris 0.04 Eucyclops elegans f Holopedium gibberum 1.64 0.03 + 4.00 115 (continued) Species Partridge Proulx Roque Ruth-Roy Shingwak Solomon Terry Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 1.41 1.37 2.17 0.86 14.40 28.27 3.11 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus 0.07 Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 0.03 + 0.01 0.53 Ophryoxus gracilis Orthocyclops modestus 0.02 Pleuroxus sp. Polyphemus pediculus 0.02 + + Scapholeberis kingi Senecella calanoides Sida crystallina Skistodiaptomus oregonensis 0.07 Skistodiaptomus reighardi 0.42 0.01 0.20 g Tropocyclops extensus 0.02 1.78 116 Species Threenarrows Turbid Whiskeyjack Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae + Alona sp.b Bosmina spp. c 0.46 0.19 Bythotrephes longimanus Ceriodaphnia sp. b + 0.05 Chydorus sphaericus + Cyclops scutifer Daphnia (Daphnia) ambigua 0.02 Daphnia (Daphnia) catawba 0.03 Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva 0.31 Daphnia (Daphnia) schodleri 0.01 Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis Daphnia (Hyalodaphnia) mendotae d 0.35 Daphnia sp. b Diacyclops bicuspidatus thomasi 0.10 Diaphanosoma birgei e 0.29 3.20 Drepanothrix dentata Epischura lacustris 0.03 Eucyclops elegans f + Holopedium gibberum 0.09 8.24 117 (continued) Species Threenarrows Turbid Whiskeyjack Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 1.35 7.27 0.04 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus 0.12 Macrocyclops albidus Macrothrix sp. Mesocyclops americanus + Mesocyclops edax 0.07 Ophryoxus gracilis Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus 0.10 0.04 Scapholeberis kingi Senecella calanoides Sida crystallina Skistodiaptomus oregonensis 0.89 Skistodiaptomus reighardi + 0.19 Tropocyclops extensus g 118 APPENDIX 5. Zooplankton species abundances (number per litre) for the 45 Killarney Survey Lakes sampled in 2000 by Holt and Yan (2003). Species Authority Acid A.Y. Jackson Bell Bodina Boundary Carlyle Acanthocyclops robustus a (Sars) Acantholeberis curvirostris (O.F. Müller) Acroperus harpae (Baird) Alona sp.b Baird Bosmina spp. c Baird 0.11 1.82 4.90 7.83 Bythotrephes longimanus Leydig Ceriodaphnia sp. b Dana 0.23 Chydorus sphaericus (O.F. Müller) Cyclops scutifer Sars Daphnia (Daphnia) ambigua Scourfield 5.08 0.18 0.17 Daphnia (Daphnia) catawba Coker 0.02 Daphnia (Daphnia) parvula Fordyce Daphnia (Daphnia) pulex and pulicaria Leydig and Forbes Daphnia (Daphnia) retrocurva Forbes 0.03 41.65 2.09 Daphnia (Daphnia) schodleri Sars 0.17 Daphnia (Hyalodaphnia) dubia Herrick 0.44 Daphnia (Hyalodaphnia) longiremis Sars 0.09 Daphnia (Hyalodaphnia) mendotae d Birge 0.91 Daphnia sp. b O.F. Müller Diacyclops bicuspidatus thomasi (Forbes) 2.32 5.93 1.16 1.22 Diaphanosoma birgei e Kořínek 1.87 9.73 8.74 4.35 Drepanothrix dentata (Eurén) Epischura lacustris Forbes Eucyclops elegans f (Herrick) Holopedium gibberum Zaddach 4.87 1.66 1.92 2.78 119 APPENDIX 5 (continued). Species Authority Acid A.Y. Jackson Bell Bodina Boundary Carlyle Ilyocryptus sp. Sars Latona setifera (O.F. Müller) Leptodiaptomus minutus (Sars) 2.25 1.91 0.10 5.42 4.70 Leptodiaptomus sicilis (Forbes) Leptodiaptomus siciloides (Lilljeborg) Leptopdiaptomus ashlandi (Marsh) Leydigia leydigi (Leydig) Limnocalanus macrurus Sars Macrocyclops albidus (Jurine) 0.23 Macrothrix sp. Baird Mesocyclops americanus Dussart Mesocyclops edax (Forbes) 0.22 0.23 3.67 0.70 Ophryoxus gracilis Sars Orthocyclops modestus (Herrick) 0.03 Pleuroxus sp. Baird Polyphemus pediculus (Linnaeus) 0.17 Scapholeberis kingi Sars Senecella calanoides Juday Sida crystallina (O.F. Müller) Skistopdiaptomus oregonensis (Lilljeborg) 0.33 0.23 0.17 0.52 Skistopdiaptomus reighardi (Marsh) 1.36 0.52 g Tropocyclops extensus (Kiefer) 0.10 16.52 0.87 a formerly Acanthocyclops vernalis complex b unable to identify, kept to genus level c pooled group. Includes Bosmina (Bosmina) liederi/freyi (De Melo and Hebert; in past referred to as Bosmina longirostris ), Eubosmina (Eubosmina) longispina (Leydig), Eubosmina (Neobosmina) tubicen (Brehm) 120 d formerly Daphnia galeata mendotae e Diaphanosoma birgei incorrectly referred to in past as Diaphanosoma leuchtenbergianum and Diaphanosoma brachyurum f formerly Eucyclops speratus g formerly Tropocyclops prasinus mexicanus h less than 0.01. 121 Species Charlton Clearsilver David deLamorandiere Evangeline Fish Freeland Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae Alona sp.b Bosmina spp. c 17.25 0.34 0.62 1.14 0.91 20.95 Bythotrephes longimanus Ceriodaphnia sp. b Chydorus sphaericus 1.02 Cyclops scutifer Daphnia (Daphnia) ambigua 0.02 0.38 1.36 Daphnia (Daphnia) catawba Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva 0.72 0.07 1.02 9.07 0.11 Daphnia (Daphnia) schodleri 0.07 Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis 13.66 Daphnia (Hyalodaphnia) mendotae d 1.44 0.31 4.45 0.11 Daphnia sp. b Diacyclops bicuspidatus thomasi 4.67 0.25 0.11 Diaphanosoma birgei e 1.80 0.04 15.76 1.52 20.41 3.48 Drepanothrix dentata Epischura lacustris 0.11 Eucyclops elegans f 0.02 Holopedium gibberum 0.05 8.16 0.89 0.45 122 (continued) Species Charlton Clearsilver David deLamorandiere Evangeline Fish Freeland Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 1.44 1.70 3.96 24.72 0.38 0.45 0.76 Leptodiaptomus sicilis Leptodiaptomus siciloides 0.02 Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus 0.36 Macrocyclops albidus 0.11 Macrothrix sp. Mesocyclops americanus Mesocyclops edax 0.36 0.13 1.55 2.03 11.34 0.54 Ophryoxus gracilis Orthocyclops modestus 0.25 Pleuroxus sp. Polyphemus pediculus Scapholeberis kingi Senecella calanoides Sida crystallina Skistopdiaptomus oregonensis 0.72 0.04 0.13 0.38 2.27 0.11 Skistopdiaptomus reighardi g Tropocyclops extensus 0.36 0.13 5.90 0.33 123 Species Frood Gail Gem George Great Mountain Helen Howry Ishmael Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae Alona sp.b Bosmina spp. c 8.16 0.22 8.96 12.60 3.50 2.17 5.05 3.82 Bythotrephes longimanus Ceriodaphnia sp. b Chydorus sphaericus 0.36 0.08 Cyclops scutifer Daphnia (Daphnia) ambigua 0.36 1.84 Daphnia (Daphnia) catawba 0.13 Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva 2.50 0.13 Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis 8.23 4.28 0.97 0.13 Daphnia (Hyalodaphnia) mendotae d 1.07 2.14 2.62 0.71 0.13 Daphnia sp. b Diacyclops bicuspidatus thomasi 4.29 3.95 24.89 4.15 3.65 3.62 3.95 Diaphanosoma birgei e 2.50 1.15 4.10 1.77 0.89 Drepanothrix dentata Epischura lacustris 0.11 0.13 Eucyclops elegans f Holopedium gibberum 1.43 0.82 1.23 0.73 0.34 0.26 0.13 124 (continued) Species Frood Gail Gem George Great Mountain Helen Howry Ishmael Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 4.65 14.32 0.49 6.76 0.41 0.57 0.18 0.64 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus 0.36 Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 5.01 1.65 0.08 0.34 0.35 0.51 Ophryoxus gracilis Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus 0.19 Scapholeberis kingi Senecella calanoides 0.34 Sida crystallina Skistopdiaptomus oregonensis 0.72 0.16 0.46 0.18 Skistopdiaptomus reighardi g Tropocyclops extensus 0.72 0.33 125 Species Johnnie Kakakise Killarney La Cloche Little Mountain Little Sheguiandah Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae Alona sp.b Bosmina spp. c 0.47 1.22 1.08 0.52 59.08 Bythotrephes longimanus Ceriodaphnia sp. b 1.46 Chydorus sphaericus 0.49 Cyclops scutifer Daphnia (Daphnia) ambigua 0.03 0.19 0.16 Daphnia (Daphnia) catawba 0.10 Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis 0.01 Daphnia (Hyalodaphnia) mendotae d 0.09 1.00 0.26 0.49 Daphnia sp. b Diacyclops bicuspidatus thomasi 1.62 2.28 0.26 Diaphanosoma birgei e 0.60 0.19 59.78 Drepanothrix dentata Epischura lacustris 0.11 0.10 Eucyclops elegans f Holopedium gibberum 1.24 0.24 2.01 0.41 126 (continued) Species Johnnie Kakakise Killarney La Cloche Little Mountain Little Sheguiandah Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 2.88 0.57 0.21 0.23 0.62 1.46 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 0.26 0.24 0.02 0.03 2.93 Ophryoxus gracilis Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus Scapholeberis kingi Senecella calanoides Sida crystallina Skistodiaptomus oregonensis 0.23 0.01 0.98 Skistodiaptomus reighardi 0.98 g Tropocyclops extensus 0.05 0.08 127 Species Little Superior Logboom Low Lumsden Muriel Nellie Norway O.S.A. Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae Alona sp.b Bosmina spp. c 26.67 0.96 5.22 5.63 1.63 Bythotrephes longimanus Ceriodaphnia sp. b 1.43 Chydorus sphaericus 0.05 Cyclops scutifer Daphnia (Daphnia) ambigua 0.01 0.05 0.08 Daphnia (Daphnia) catawba Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis Daphnia (Hyalodaphnia) mendotae d 0.24 5.12 Daphnia sp. b Diacyclops bicuspidatus thomasi 0.24 4.80 0.20 Diaphanosoma birgei e 0.04 2.86 0.96 0.16 Drepanothrix dentata Epischura lacustris Eucyclops elegans f Holopedium gibberum 7.14 1.60 9.59 6.00 128 (continued) Species Little Superior Logboom Low Lumsden Muriel Nellie Norway O.S.A. Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 0.78 1.60 0.71 2.82 6.82 1.38 0.16 Leptodiaptomus sicilis 0.32 0.03 Leptodiaptomus siciloides 0.08 Leptopdiaptomus ashlandi 0.32 Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 1.67 0.96 0.01 3.67 0.11 Ophryoxus gracilis Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus Scapholeberis kingi Senecella calanoides Sida crystallina Skistodiaptomus oregonensis 0.03 Skistodiaptomus reighardi 2.62 0.03 0.05 g Tropocyclops extensus 1.43 129 Species Partridge Proulx Roque Ruth-Roy Shingwak Solomon Terry Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae 0.07 Alona sp.b Bosmina spp. c 8.42 0.14 0.08 0.14 12.64 Bythotrephes longimanus Ceriodaphnia sp. b Chydorus sphaericus 0.04 Cyclops scutifer Daphnia (Daphnia) ambigua 2.17 Daphnia (Daphnia) catawba 0.87 Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis Daphnia (Hyalodaphnia) mendotae d Daphnia sp. b Diacyclops bicuspidatus thomasi 0.09 0.08 6.09 Diaphanosoma birgei e 0.03 12.61 Drepanothrix dentata Epischura lacustris Eucyclops elegans f Holopedium gibberum 0.54 12.18 130 (continued) Species Partridge Proulx Roque Ruth-Roy Shingwak Solomon Terry Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 1.88 0.24 7.86 1.83 1.00 8.69 0.87 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus 0.07 Macrothrix sp. + h Mesocyclops americanus Mesocyclops edax 0.43 Ophryoxus gracilis + Orthocyclops modestus Pleuroxus sp. 0.19 Polyphemus pediculus Scapholeberis kingi Senecella calanoides Sida crystallina Skistodiaptomus oregonensis Skistodiaptomus reighardi g Tropocyclops extensus 16.09 131 Species Threenarrows Turbid Whiskeyjack Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae Alona sp.b Bosmina spp. c 2.24 5.40 Bythotrephes longimanus Ceriodaphnia sp. b 7.74 Chydorus sphaericus Cyclops scutifer 0.30 Daphnia (Daphnia) ambigua 0.12 0.30 Daphnia (Daphnia) catawba Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva 0.10 0.30 Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis 0.03 0.30 Daphnia (Hyalodaphnia) mendotae d 2.55 Daphnia sp. b Diacyclops bicuspidatus thomasi 1.04 Diaphanosoma birgei e 1.96 23.81 0.03 Drepanothrix dentata Epischura lacustris 0.01 Eucyclops elegans f Holopedium gibberum 0.27 15.78 132 (continued) Species Threenarrows Turbid Whiskeyjack Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 2.65 2.98 1.48 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi 0.35 Leydigia leydigi Limnocalanus macrurus 0.49 Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 0.66 0.30 Ophryoxus gracilis Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus Scapholeberis kingi Senecella calanoides 0.02 Sida crystallina Skistodiaptomus oregonensis 0.63 Skistodiaptomus reighardi Tropocyclops extensus g 133 APPENDIX 6. Zooplankton species abundances (number per litre) for the 45 Killarney Survey Lakes sampled in 2005 Species Authority Acid A.Y. Jackson Bell Bodina Boundary Carlyle Acanthocyclops robustus a (Sars) 0.42 Acantholeberis curvirostris (O.F. Müller) Acroperus harpae (Baird) Alona sp.b Baird Bosmina spp. c Baird 1.96 6.19 11.59 34.81 7.61 Bythotrephes longimanus Leydig Calanoid Copepodid 0.33 3.33 1.57 15.07 43.21 3.29 Calanoid Nauplius 2.95 1.12 1.68 1.74 9.89 1.50 Ceriodaphnia sp. b Dana 0.58 Chydorus sphaericus (O.F. Müller) Cyclopoid Copepodid O.F. Müller 1.67 0.25 7.98 49.20 2.28 3.67 Cyclopoid Nauplius O.F. Müller 2.33 0.62 7.35 38.88 6.46 13.45 Cyclops scutifer Sars 0.10 Daphnia (Daphnia) ambigua Scourfield 0.09 Daphnia (Daphnia) catawba Coker Daphnia (Daphnia) parvula Fordyce Daphnia (Daphnia) pulex and pulicaria Leydig and Forbes Daphnia (Daphnia) retrocurva Forbes Daphnia (Daphnia) schodleri Sars Daphnia (Hyalodaphnia) dubia Herrick Daphnia (Hyalodaphnia) longiremis Sars 0.10 Daphnia (Hyalodaphnia) mendotae d Birge 0.08 Daphnia sp. b O.F. Müller Diacyclops bicuspidatus thomasi (Forbes) 0.59 0.08 4.40 Diaphanosoma birgei e Kořínek 0.21 0.52 18.54 4.94 0.66 134 APPENDIX 6 (continued). Species Authority Acid A.Y. Jackson Bell Bodina Boundary Carlyle Drepanothrix dentata (Eurén) Epischura lacustris Forbes Epischura lacustris Copepodid Forbes Eucyclops elegans f (Herrick) Holopedium gibberum Zaddach 2.04 1.57 0.58 11.03 11.37 Ilyocryptus sp. Sars Latona setifera (O.F. Müller) Leptodiaptomus minutus (Sars) 0.55 2.17 1.89 1.16 23.13 2.73 Leptodiaptomus sicilis (Forbes) Leptodiaptomus siciloides (Lilljeborg) Leptopdiaptomus ashlandi (Marsh) Leydigia leydigi (Leydig) Limnocalanus macrurus Sars Macrocyclops albidus (Jurine) Macrothrix sp. Baird Mesocyclops americanus Dussart Mesocyclops edax (Forbes) 0.73 5.79 0.76 0.28 Ophryoxus gracilis Sars Orthocyclops modestus (Herrick) 0.12 Pleuroxus sp. Baird Polyphemus pediculus (Linnaeus) 0.38 Scapholeberis kingi Sars Senecella calanoides Juday Senecella calanoides Copepodid Juday Sida crystallina (O.F. Müller) Skistopdiaptomus oregonensis (Lilljeborg) 135 APPENDIX 6 (continued). Species Authority Acid A.Y. Jackson Bell Bodina Boundary Carlyle Skistodiaptomus reighardi (Marsh) 15.65 g Tropocyclops extensus (Kiefer) 0.37 1.05 61.89 a formerly Acanthocyclops vernalis complex b unable to identify, kept to genus level c pooled group. Includes Bosmina (Bosmina) liederi/freyi (De Melo and Hebert; in past referred to as Bosmina longirostris ), Eubosmina (Eubosmina) longispina (Leydig), Eubosmina (Neobosmina) tubicen (Brehm) d formerly Daphnia galeata mendotae e Diaphanosoma birgei incorrectly referred to in past as Diaphanosoma leuchtenbergianum and Diaphanosoma brachyurum f formerly Eucyclops speratus g formerly Tropocyclops prasinus mexicanus h less than 0.01. 136 Species Charlton Clearsilver David deLamorandiere Evangeline Fish Freeland Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae + h + Alona sp.b 0.01 0.63 Bosmina spp. c 5.15 3.40 0.06 2.76 1.88 0.75 Bythotrephes longimanus Calanoid Copepodid 0.57 0.04 63.89 119.81 11.03 0.30 1.13 Calanoid Nauplius 9.73 0.02 5.85 12.69 4.48 1.65 4.57 Ceriodaphnia sp. b Chydorus sphaericus 0.05 Cyclopoid Copepodid 12.59 + 0.74 1.32 11.72 0.91 32.27 Cyclopoid Nauplius 96.15 0.06 2.22 7.66 60.65 23.72 25.58 Cyclops scutifer Daphnia (Daphnia) ambigua 0.22 1.38 Daphnia (Daphnia) catawba 0.07 Daphnia (Daphnia) parvula 1.11 0.69 Daphnia (Daphnia) pulex and pulicaria 0.86 0.37 Daphnia (Daphnia) retrocurva 2.00 2.07 Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia 1.43 Daphnia (Hyalodaphnia) longiremis 5.72 1.72 Daphnia (Hyalodaphnia) mendotae d 0.86 8.27 Daphnia sp. b 9.44 0.69 0.03 Diacyclops bicuspidatus thomasi 8.87 + 0.69 0.01 Diaphanosoma birgei e 14.31 0.05 13.44 0.10 137 (continued) Species Charlton Clearsilver David deLamorandiere Evangeline Fish Freeland Drepanothrix dentata Epischura lacustris Epischura lacustris Copepodid 0.04 Eucyclops elegans f Holopedium gibberum 0.29 1.55 0.34 0.25 Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 1.14 0.03 2.96 18.67 5.17 0.01 0.31 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 0.57 + 1.85 0.12 7.58 0.01 0.03 Ophryoxus gracilis Orthocyclops modestus 0.06 Pleuroxus sp. Polyphemus pediculus + 0.06 Scapholeberis kingi Senecella calanoides Senecella calanoides Copepodid Sida crystallina Skistopdiaptomus oregonensis 2.29 6.55 0.01 138 (continued) Species Charlton Clearsilver David deLamorandiere Evangeline Fish Freeland Skistodiaptomus reighardi g Tropocyclops extensus 0.07 13.10 0.40 7.53 139 Species Frood Gail Gem George Great Mountain Helen Howry Ishmael Acanthocyclops robustus a 0.67 Acantholeberis curvirostris Acroperus harpae + Alona sp.b + Bosmina spp. c 2.95 8.74 4.25 4.57 5.51 5.35 Bythotrephes longimanus Calanoid Copepodid 4.32 100.24 12.77 0.56 0.28 15.12 4.27 9.67 Calanoid Nauplius 4.09 1.60 2.69 1.36 2.89 3.13 4.41 4.33 Ceriodaphnia sp. b Chydorus sphaericus 0.01 0.06 Cyclopoid Copepodid 4.09 + 9.64 46.14 2.73 5.45 3.72 14.25 Cyclopoid Nauplius 36.28 + 13.84 39.78 13.13 6.36 24.71 14.37 Cyclops scutifer Daphnia (Daphnia) ambigua Daphnia (Daphnia) catawba 0.28 Daphnia (Daphnia) parvula 0.14 Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva 1.36 0.25 Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis 0.45 Daphnia (Hyalodaphnia) mendotae d 12.26 2.24 0.24 2.24 1.10 0.51 Daphnia sp. b Diacyclops bicuspidatus thomasi 2.50 4.93 3.45 2.39 2.69 2.34 3.31 Diaphanosoma birgei e 5.45 + 3.59 2.81 0.28 5.93 6.62 140 (continued) Species Frood Gail Gem George Great Mountain Helen Howry Ishmael Drepanothrix dentata Epischura lacustris 0.18 1.27 Epischura lacustris Copepodid 0.45 2.04 Eucyclops elegans f Holopedium gibberum 0.45 0.24 0.85 0.63 0.28 1.78 Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 8.40 11.75 3.14 2.89 2.05 2.42 2.21 4.84 Leptodiaptomus sicilis 0.09 Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 1.59 0.22 0.16 0.06 0.09 0.69 3.05 Ophryoxus gracilis Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus + Scapholeberis kingi Senecella calanoides Senecella calanoides Copepodid Sida crystallina Skistopdiaptomus oregonensis 3.63 0.09 0.69 0.25 141 (continued) Species Frood Gail Gem George Great Mountain Helen Howry Ishmael Skistodiaptomus reighardi g Tropocyclops extensus 0.45 1.34 0.27 0.25 142 Species Johnnie Kakakise Killarney La Cloche Little Mountain Little Sheguiandah Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae Alona sp.b Bosmina spp. c 4.05 10.88 1.05 3.19 0.01 10.47 Bythotrephes longimanus 0.11 Calanoid Copepodid 5.24 7.15 15.13 4.08 2.37 Calanoid Nauplius 2.07 3.41 22.43 7.86 10.56 6.53 Ceriodaphnia sp. b 0.50 Chydorus sphaericus + Cyclopoid Copepodid 4.05 13.16 0.02 11.78 54.79 2.25 Cyclopoid Nauplius 13.07 42.34 0.02 3.75 12.96 Cyclops scutifer Daphnia (Daphnia) ambigua Daphnia (Daphnia) catawba Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis Daphnia (Hyalodaphnia) mendotae d 0.08 0.97 0.44 Daphnia sp. b Diacyclops bicuspidatus thomasi 1.16 5.20 1.54 Diaphanosoma birgei e 0.81 0.77 + 0.12 143 (continued) Species Johnnie Kakakise Killarney La Cloche Little Mountain Little Sheguiandah Drepanothrix dentata Epischura lacustris 0.32 0.11 Epischura lacustris Copepodid 0.16 Eucyclops elegans f Holopedium gibberum 0.58 0.24 + Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 2.56 3.25 1.27 5.07 6.77 0.06 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 0.32 + 0.11 Ophryoxus gracilis Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus Scapholeberis kingi Senecella calanoides Senecella calanoides Copepodid Sida crystallina Skistodiaptomus oregonensis 0.44 144 (continued) Species Johnnie Kakakise Killarney La Cloche Little Mountain Little Sheguiandah Skistodiaptomus reighardi 0.06 g Tropocyclops extensus 1.87 3.26 145 Species Little Superior Logboom Low Lumsden Muriel Nellie Norway O.S.A. Acanthocyclops robustus a 0.02 Acantholeberis curvirostris Acroperus harpae + Alona sp.b Bosmina spp. c + 71.65 8.08 7.98 + 19.48 0.10 Bythotrephes longimanus Calanoid Copepodid 30.95 0.31 16.89 0.31 10.02 15.40 22.82 27.49 Calanoid Nauplius 24.48 3.62 13.22 4.62 5.60 12.63 2.69 33.60 Ceriodaphnia sp. b Chydorus sphaericus ++ Cyclopoid Copepodid 0.72 15.05 0.54 1.87 Cyclopoid Nauplius + 8.87 60.59 6.93 23.27 + 0.02 Cyclops scutifer Daphnia (Daphnia) ambigua Daphnia (Daphnia) catawba Daphnia (Daphnia) parvula 0.01 Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis Daphnia (Hyalodaphnia) mendotae d 0.14 0.73 + 0.01 Daphnia sp. b + Diacyclops bicuspidatus thomasi 24.60 0.46 Diaphanosoma birgei e 0.05 4.92 + 0.23 + 146 (continued) Species Little Superior Logboom Low Lumsden Muriel Nellie Norway O.S.A. Drepanothrix dentata Epischura lacustris Epischura lacustris Copepodid Eucyclops elegans f Holopedium gibberum 0.15 0.37 3.06 + 0.70 Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 6.24 0.11 11.75 1.39 6.79 3.48 0.66 2.43 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi 0.02 Limnocalanus macrurus Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax + 0.06 1.53 0.01 Ophryoxus gracilis Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus +++ Scapholeberis kingi Senecella calanoides 0.37 Senecella calanoides Copepodid Sida crystallina Skistodiaptomus oregonensis 0.12 147 (continued) Species Little Superior Logboom Low Lumsden Muriel Nellie Norway O.S.A. Skistodiaptomus reighardi g Tropocyclops extensus 0.43 148 Species Partridge Proulx Roque Ruth-Roy Shingwak Solomon Terry Acanthocyclops robustus a Acantholeberis curvirostris Acroperus harpae ++ + Alona sp.b 5.55 + Bosmina spp. c 4.24 + 0.03 0.10 9.59 Bythotrephes longimanus Calanoid Copepodid 28.15 60.52 56.65 34.60 24.09 534.62 3.91 Calanoid Nauplius 4.24 5.64 35.84 57.28 17.44 448.70 8.52 Ceriodaphnia sp. b Chydorus sphaericus + + 0.01 + 0.03 Cyclopoid Copepodid + 0.12 15.62 Cyclopoid Nauplius 15.01 + 0.05 0.02 + 57.98 16.16 Cyclops scutifer Daphnia (Daphnia) ambigua Daphnia (Daphnia) catawba 0.36 Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis Daphnia (Hyalodaphnia) mendotae d + Daphnia sp. b Diacyclops bicuspidatus thomasi 0.71 Diaphanosoma birgei e 1.75 0.21 9.94 149 (continued) Species Partridge Proulx Roque Ruth-Roy Shingwak Solomon Terry Drepanothrix dentata Epischura lacustris Epischura lacustris Copepodid Eucyclops elegans f Holopedium gibberum 2.34 0.66 9.23 Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 16.46 3.39 32.67 1.42 9.62 100.29 23.03 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax + + + 0.01 1.07 Ophryoxus gracilis Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus +++ Scapholeberis kingi Senecella calanoides Senecella calanoides Copepodid Sida crystallina Skistodiaptomus oregonensis 150 (continued) Species Partridge Proulx Roque Ruth-Roy Shingwak Solomon Terry Skistodiaptomus reighardi g Tropocyclops extensus + 1.07 151 Species Threenarrows Turbid Whiskeyjack Acanthocyclops robustus a 0.30 Acantholeberis curvirostris Acroperus harpae Alona sp.b Bosmina spp. c 1.20 1.40 + Bythotrephes longimanus Calanoid Copepodid 4.61 11.69 35.71 Calanoid Nauplius 3.91 8.18 5.48 Ceriodaphnia sp. b Chydorus sphaericus + Cyclopoid Copepodid 2.10 Cyclopoid Nauplius 6.34 1.17 + Cyclops scutifer Daphnia (Daphnia) ambigua Daphnia (Daphnia) catawba 0.10 Daphnia (Daphnia) parvula Daphnia (Daphnia) pulex and pulicaria Daphnia (Daphnia) retrocurva Daphnia (Daphnia) schodleri Daphnia (Hyalodaphnia) dubia Daphnia (Hyalodaphnia) longiremis Daphnia (Hyalodaphnia) mendotae d 0.30 Daphnia sp. b Diacyclops bicuspidatus thomasi 2.60 Diaphanosoma birgei e 1.70 18.12 152 (continued) Species Threenarrows Turbid Whiskeyjack Drepanothrix dentata Epischura lacustris 0.20 Epischura lacustris Copepodid 0.20 Eucyclops elegans f Holopedium gibberum 0.50 13.20 Ilyocryptus sp. Latona setifera Leptodiaptomus minutus 2.70 13.86 2.71 Leptodiaptomus sicilis Leptodiaptomus siciloides Leptopdiaptomus ashlandi Leydigia leydigi Limnocalanus macrurus Macrocyclops albidus Macrothrix sp. Mesocyclops americanus Mesocyclops edax 1.80 Ophryoxus gracilis Orthocyclops modestus Pleuroxus sp. Polyphemus pediculus 0.23 Scapholeberis kingi Senecella calanoides 0.10 Senecella calanoides Copepodid 0.60 Sida crystallina Skistodiaptomus oregonensis 153 (continued) Species Threenarrows Turbid Whiskeyjack Skistodiaptomus reighardi g Tropocyclops extensus 0.20 0.23 154