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Home , Alvar, Anemonastrum, Clematis, Comandra, Pellaea glabella, Ribes oxyacanthoides

Manitoba’s endangered alvars: an initial description of their extent and status

Rebekah Neufeld1, *, Cary Hamel2, and Chris Friesen3

1Nature Conservancy of Canada, Region, 207 — 1570 18th Street, Brandon, Manitoba R7A 5C5 Canada 2Nature Conservancy of Canada, Manitoba Region, 200 — 611 Corydon Avenue, Winnipeg, Manitoba R3L 0P3 Canada 3Manitoba Conservation Data Centre, P.O. Box 24, 200 Saulteaux Crescent, Winnipeg, Manitoba R3J 3W3 Canada *Corresponding author: [email protected]

Neufeld, R., C. Hamel, and C. Friesen. 2018. Manitoba’s endangered alvars: an initial description of their extent and status. Canadian Field-Naturalist 132(3): 238–253. https://doi.org/10.22621/cfn.v132i3.1865

Abstract Alvars are rare in Canada and uncommon globally. This study represents the first formal attempt to describe and delineate the extent of alvars in Manitoba. A systematic examination of the Interlake region’s edaphic and biological characteristics, using a geographic information system, resulted in the identification of 67 sites warranting further field study. Of these sites, 61 were surveyed and information was collected on vegetation composition and structure, soil characteristics, land ownership, and land use. Alvar was confirmed at 28 sites, extending over approximately 3930 ha in five geographically distinct clusters. Four putative types of alvar communities are described: grassland, shrubland, savannah, and wetland. Livestock grazing is the dominant land use and occurs across more than three-quarters of Manitoba alvar. Approximately 12% coincide with mining claims or quarry leases. Two-thirds occur on publicly owned land. Key words: Alvar; karst; endangered ecosystem; Manitoba; Interlake; ; dolomite Introduction ba between the southern basins of Lakes Manitoba and Alvars are globally uncommon ecosystems that are Winnipeg, i.e., the Interlake region (Hamel and Foster distinctive for their unusual composition 2004). In 2011, an alvar expert (John Riley) and associations and natural openness in otherwise accompanied us to one of these locations and confirmed forested regions (Catling and Brownell 1995; Reshcke that the ecosystem shared characteristics consistent with et al. 1999), although alvar woodlands and the asso- alvar ecosystems in Ontario and were worthy of further ciated successional stages are also important compo- study and formal description. nents (Catling and Brownell 1999a; Catling et al. In 2015, the Manitoba government listed alvar as 2002; Brunton and Catling 2017). Alvars have thin or endangered under the Manitoba Endangered Species absent soils underlain by flat limestone or dolomitic and Ecosystems Act using the authors’ unpublished in­ bedrock that restricts drainage; thus, they are subject to formation to support determination of its conservation extreme variations in moisture availability that range status. from drought conditions to periodic flooding (Brunton The results of this study were previously published in 1988; Catling and Brownell 1995; Reschke et al. 1999; a technical report (Manitoba Alvar Initiative 2012). This Catling 2009a). The physical structure and species com- paper refines those results and confirms the findings in position of alvar plant communities can vary; Great the context of the established body of knowledge on Lakes alvars, for example, have been differentiated into North American alvars. The objectives of this study 13 types (Reschke et al. 1999). In Manitoba, alvar-like were to survey and map alvars in the Interlake region of ecosystems that support species characteristic of both Manitoba; to describe their physical structure and spe- and boreal forest, with a limited occurrence of cies composition; and to determine land ownership and trees and occasional exposure of dolomitic pavement, land uses of Manitoba alvars. have been described (Hamel and Foster 2004). In Canada, alvars are found in the Great Lakes re- Methods gion, (Reschke et al. 1999), and the Northwest We used a geographic information system (GIS) to Territories (Catling 2009a). The presence of alvar in identify and delineate 67 sites of potential alvar encom- Manitoba was noted by Catling (2009a), but no infor- passing 6313 ha (Figure 1) in the south Interlake and mation on its extent was provided. Although the precise adjacent regions. We examined spatial data layers of extent of alvars in is not yet known, geomorphologic and vegetative features representa- their distribution is fragmented and loosely follows the tive of alvar-like sites identified by Hamel and Foster edge of the Canadian Shield where postglacial meltwa- (2004). Layers included orthophotographs (to assess ters have exposed limestone bedrock (Catling 2009a). vegetation cover), soil classification data (to determine Before our study, alvar-like ecosystems associated with soil depth and the presence of near-surface limestone near-surface dolomitic and inland bedrock), and a digital elevation model (to identify the cliffs had been documented at five locations in Manito- location of ridges; Manitoba Conservation and Water

238 ©This work is freely available under the Creative Commons Attribution 4.0 International license (CC BY 4.0). 2018 Neufeld et al.: Manitoba’s alvars 239

Figure 1. Survey locations (stars) were considered potential locations for alvar based on similarities in geological and soil characteristics to previously confirmed communities in Manitoba. Stewardship 2012a). Between June and August 2012, rock that restricts drainage; soil thin—with a depth up we surveyed and assessed 61 sites to determine wheth- to 15 cm that is not the result of mechanical removal er they supported alvar. We attempted to visit all poten- —or absent (criterion used by Brunton 1988; Catling tial sites regardless of ownership, but we did not receive and Brownell 1995; Reschke et al. 1999); and tree permission to access six private land parcels. canopy cover <60% (criterion used by Reschke et al. A site was determined to be alvar if it met the follow- 1999). Although alvars can occur on soil deeper than ing criteria: presence of flat limestone or dolomite bed- 15 cm (Reschke et al. 1999), such sites were not in- 240 The Canadian Field-Naturalist 2018 cluded in the estimation of extent for this study be- The bedrock composition of the limestone underly- cause they could not be confirmed as being alvars with- ing alvar was compared at each site by overlaying the out more detailed analyses of the species composition mapped alvar polygons with a GIS shapefile of the geo- and/or investigation of other ecologically distinct char- logical periods of bedrock formation (Manitoba Miner- acteristics resulting from the influence of an underlying al Resources 2012a) to identify patterns related to alvar bedrock pavement. type and distribution. If not visible at the surface, limestone pavement was detected by digging small test holes. We determined soil Results and Discussion depth by pressing a metal rod into the soil and measur- Extent and distribution ing depth at impact with bedrock. Evidence of extreme Alvar was found at 28 of the 61 survey locations, moisture variability was based on observations of stand- with a maximum extent of ~3934 ha. Alvars >16 ha ing water following rain events, the presence of algae often supported internal patches of non-alvar ecosys- on dry pavement, thin bare soil (without evidence of dis- tems, such as forest or prairie, where soil depth was turbance), and restricted vegetation and lichen growth greater than 15 cm. patterns. We recorded qualitative observations of the We mapped 101 spatially distinct units of alvar, dominant plant species, soil depth, unique topographic varying from 0.4 ha to 809 ha and grouped these units features, land use, and patterns of flooding, drought, into five geographically distinct sites (Figure 2). The and drainage. Marble Ridge Alvar, referred to as Marble Ridge A, The potential extent of alvar at each survey site was B, and C Alvars, follows a limestone formation of the mapped as polygons in GIS. Boundaries were delin- same name, along which inland limestone cliffs are also eated by using ground-truthed global positioning sys- found. The Peguis Alvar is immediately east of the Pe- tem coordinates and interpreting orthophotographs. guis First Nation Reserve, and the Sylvan Alvar is al- These maps indicate the estimated maximum extent of most completely within the boundaries of the Sylvan the alvar communities observed. Within mapped hab- Dale Community Pasture. The Poplarfield Alvar rep- itat patches, there may be areas without alvar, or an area resents a group of small, isolated units near Poplarfield. may represent a mosaic of alvar and other ecosystems. The Alvar is located in and around the Clem- Dominant physiognomic characteristics were used to atis and Sandridge Wildlife Management Areas. categorize alvars into types to better describe the vari- Alvar types ation observed. Alvar types were characterized first by Alvars were categorized into four putative types: growth form (tree, , forb, or graminoid), then ver- grassland (graminoid dominated, <10% tree cover, up- tical structure (<10% tree canopy or 10–60% tree can- land affinity), shrubland (shrub dominated, <10% tree opy, comparable to thresholds used to distinguish savan- cover, upland affinity), savannah (shrub dominated, nah from other upland ecosystems found in the Interlake >10% tree cover, upland affinity), and wetland (gram- region; Minnesota Department of Natural Resources inoid dominated, <10% tree cover, wetland affinity). 2005), and, finally, by wetland or upland species affini- Many sites supported multiple types of alvar occurring ties. Putative descriptions of each type’s composition in combination. A list of plant and lichen species ob- and variation were prepared using the data collected served in each alvar type is shown in Table 1, but quan- during site surveys. We used vegetation survey plots at titative values are not presented as the plot data are not a small sample of sites to supplement the general survey fully representative of the variation that exists within data and test the accuracy of these descriptions. Nine the types described. 20 m × 50 m plots, distributed among four sites, were Grassland alvars have nearly continuous vegetative randomly placed in what appeared to be unique sub- cover, with soil depth typically ranging from 5 cm to types of alvar. Each plot was divided into six subplots: 10 cm, and only occasional patches of limestone pave- one 20 m × 20 m; four 10 m × 10 m; and one 20 m × ment (Figure 3). They are dominated by upland gram- 10 m. The canopy cover of vascular , bryophytes, inoid species, with high forb and low shrub cover. Trees and lichens was recorded by visual observation within are typically absent or restricted to the periphery. Moss the four 10 m × 10 m subplots using the following cov- provides significant ground cover among and beneath er classes: <0.1%, 0.1 to <1%, 1 to <2%, 2 to <5%, 5 to other vegetation. Bare soil, exposed limestone, and <10%, 10 to <25%, 25 to <50%, 75 to <95% and ≥95%. bryophyte and lichen growth directly on the limestone The additional two plots were used to capture the cover pavement were uncommon. These sites are generally class of any species not recorded in the initial four plots. flat, although some areas have small (typically <1 m in Soil depth was recorded on the centre line and at 10 m height) outcrops along the edges of plateau formations. and 30 m along the plot starting from the 10 m × 20 m We observed less evidence of flooding following rain end. Voucher specimens obtained for vascular plants, compared with other alvars, although drainage is re- bryophytes, and lichens were deposited in the Univer- stricted and water pools on the limestone pavement. sity of Manitoba herbarium (WIN). A statistical anal- We did not observe conditions immediately following ysis was not completed. spring melt. 2018 Neufeld et al.: Manitoba’s alvars 241

Figure 2. Confirmed locations of alvar in Manitoba. Individual patches of alvar have been grouped into five sites. Marble Ridge A, B, and C together constitute a single site.

In shrubland alvars (Figures 4, 5, and 6) vegetative dominant cover, followed by forbs, with cover is generally patchy and often restricted to cracks graminoids frequent, but not as abundant as in grassland and seams in the bedrock with deeper soils. Soil depth alvars. Tree cover is greater than in grassland alvars, but is shallower than in grassland alvars, typically <5 cm, still low, and trees generally appear to be stunted. Cov- and limestone pavement is frequent. are the er of bryophytes, lichens, and bare soil is much higher 242 The Canadian Field-Naturalist 2018 X X X Wetland X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Savannah Alvar type X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Shrubland

X X X X X X X X X X Grassland

S4S5 S5 SNA S5 S3 S5 S5 S5 S5 S5 S5 S5 S5 S5 S4S5 S5 S3S5 S5 S5 SNA S5 S5 S5 S4 S5 S2S3 S4 S5 S4S5 S5 S4S5 Subnational G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5T5 G5 Conservation status* Global Common name Pale Agoseris Pale Rough Bentgrass Creeping Bentgrass Autumn Onion Prairie Onion Saskatoon Ragweed species Big Bluestem Canada Anemone Long-headed Anemone Cut-leaved Pussytoes species Mountain Death Camas Spreading Dogbane Hairy Rockcress Rockcress species Common Bearberry Wormwood Field Wormwood Silver Milkweed species Water Paper Birch Bog Birch Smooth Brome Bellflower Giesecke’s Sedge species Field Chickweed Goosefoot species Thistle species Toadflax Bastard American Hazelnut Slipper Lady’s Purple Prairie-clover Porter’s Brome Porter’s Thistle Drummond’s Yarrow Common Poverty Oatgrass Shrubby Cinquefoil Hairgrass Tufted

Species

(Vest ex Shultes) (Vest (L.) Sprengel Nuttall (Nuttall) Nuttall ex M. Roemer L. A. Gray Hooker Poiret (L.) P. Beauvois ex Roemer & Schultes (L.) P. Marshall (Pursh) Rydberg Fraser ex Ker Gawler L. A. Nelson & J.F. Macbride A. Nelson & J.F. spp. pla n ts

sp. Vascular plants, bryophytes, and lichens observed in each type of alvar. Vascular 1. as c ular able Scientific name

Agoseris glauca (Pursh) Rafinesque scabra Willdenow Agrostis stolonifera L. Agrostis Allium stellatum Allium textile Amelanchier alnifolia spp. Ambrosia Vitman gerardi Andropogon Anemonastrum canadense (L.) Mosyakin Anemone cylindrica Anemone multifida Anticlea elegans L. Apocynum androsaemifolium Arabis hirsuta (L.) Scopoli Arabis sp. uva-ursi Arctostaphylos Artemisia campestris L. Artemisia ludoviciana Asclepias Betula occidentalis Betula papyrifera Betula pumila inermis Leysser Bromus Campanula gieseckeana spp . Cerastium arvense L. Chenopodium spp. Cirsium sp. Comandra umbellata (L.) Nuttall Corylus americana Walter Cypripedium sp. Ventenat Dalea purpurea Danthonia spicata Bromus porteri (J.M. Coult) Nash Bromus A. Gray & Cirsium drummondii Torrey T V Achillea millefolium Dasiphora fruticosa (L.) Rydberg Deschampsia cespitosa (L.) Palisot de Beauvois 2018 Neufeld et al.: Manitoba’s alvars 243 X X X Wetland

X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Savannah Alvar type X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Shrubland

X X X X X X X X X X X X Grassland

S5 S5 S3 S5 S5 S5 S4S5 S5 S3S4 S5 S5 S5 S5 S5 S4 S4 S5 S4 S5 S5 S5 S5 SNA S3S5 S5 S4S5 S5 S3S4 S1 S3 S5 S2 SNA S5 S5 Subnational G5T5 G5 G4 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5? G5 G5 G5 G5 G5 G5 G5 GNR G5 G5 G5 G5 G5 G2G3 G5 G5 G5T4 GNR G5 G5 Conservation status* Global Common name Wildrye Slender Philadelphia Fleabane Fleabane species Rough Fescue Strawberry Wild Great Blanketflower Northern Bedstraw Avens Three-flowered Curly-cup Gumweed Sunflower species Oatgrass Hooker’s Umbellate Hawkweed Rush Dudley’s Common Juniper Creeping Juniper Prairie Junegrass species Vetch species Peppergrass Meadow Blazing-star Lily Wood Twinflower Blue Flax Wild Lewis’ Hoary Puccoon Limber Honeysuckle Lily-of-the-valley Wild Seal Starflower False Solomon’s Black Medick American Cow-wheat Bergamot Wild Owl’s-clover Yellow Rough-leaved Mountain Rice Indian Breadroot Large Cliffbrake Gastony’s Phlox Hood’s Richardson’s Alumroot Richardson’s Dwarf Cliffbrake Western Timothy Common Tall Wood Beauty Wood Tall Spikerush species Wildrye One-sided

Species Windham (E.E. Nelson) (Pursh) Rydberg L. (L.) Link L. L. (Scribner) Romero Zarco (Link) Gould ex Shinners subsp. subsecundus (Link) Á. Löve & D. (Ledebour) Schultes ) (L.) (A. Nelson) K. Schumann (L.) Windham subsp. occidentalis L. Wiegand (Vasey) Piper (Vasey) Pursh Richardson spp. 1. ( continued able T Elymus trachycaulus philadelphicus Erigeron spp . Erigeron Festuca hallii Miller virginiana aristata Pursh Gaillardia L. Galium boreale Geum triflorum Pursh (Pursh) Dunal Grindelia squarrosa Helianthus sp. Helictochloa hookeri Hieracium umbellatum Juncus dudleyi Juniperus communis L. Juniperus horizontalis Moench Koeleria macrantha Lathyrus sp. Lepidium sp. Liatris ligulistylis Lilium philadelphicum L. Linnaea borealis Linum lewisii Lithospermum canescens (Michaux) Lehmann Lonicera dioica Maianthemum canadense Desfontaines Maianthemum stellatum Medicago lupulina Desrousseaux Melampyrum lineare fistulosa (L.) Monarda Orthocarpus luteus Nutall Oryzopsis asperifolia Michaux Pediomelum esculentum gastonyi Phlox hoodii Scientific name R. Brown Heuchera richardsonii Pellaea glabella Phleum pratense (Pursh) Rydberg Drymocallis arguta Eleocharis Elymus trachycaulus 244 The Canadian Field-Naturalist 2018 X Wetland

X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Savannah Alvar type X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Shrubland

X X X X X X X X X Grassland

S5 S4 S5 S5 SU S4 SU S5 S5 S3S4 S5 S5 S5 S5 S5 S3 S5 S4S5 S5 S5 S5 S4S5 S4 S5 SNA S5 S5 S4S5 S5 S5 S5 S5 S5 SNA Subnational G5 G4G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 GNR Conservation status* Global Common name Kentucky Bluegrass Bluegrass species Seneca Snakeroot Aspen Trembling Common Silverweed Bipinnate Cinquefoil Slender Cinquefoil Pennsylvania Cinquefoil Pin Cherry Chokecherry Smooth Sumac Canada Gooseberry Prickly Red Raspberry Black-eyed-Susan species Willow Maryland Sanicle Prairie Spikemoss Strict Blue-eyed-grass Hairy-nerved Carrionflower Hairy Goldenrod Goldenrod Grey-stemmed Goldenrod White Goldenrod Upland Goldenrod species Snowberry species species Aster White Heath Aster Smooth Common Dandelion Meadow-rue Veiny Poison Ivy Western Arrowwood Downy Vetch American Cinquefoil species Bur Soapberry White Spruce Jack Annual Bluegrass Species (L.) G.L. Nesom L. Douglas ex Hooker (L.) Á. Löve & D. (Torrey & A. Gray) B. Boivin & (Torrey L. L. Wiggers F.H. L. f. ) Vascular plants, bryophytes, and lichens observed in each type of alvar. Vascular ) (L.) subsp. anserina Douglas ex Hooker Hooker Rydberg Willdenow ex Muhlengerg Willdenow ex Muhlenberg L. L. Lindley (Moench) Voss sp. 1. ( continued spp. able T Poa pratensis L. Poa sp. Polygala senega Michaux tremuloides Potentilla anserina Potentilla bipinnatifida Potentilla gracilis Potentilla pensylvanica Prunus pensylvanica L. Prunus virginiana Rhus glabra L. oxyacanthoides Rosa acicularis idaeus L. Rudbeckia hirta Salix Sanicula marilandica densa Sisyrinchium montanum Greene Smilax lasioneura hispida Solidago missouriensis Nuttall Solidago nemoralis Aiton Solidago ptarmicoides Solidago spp. Symphoricarpos sp. spp. Symphyotrichum ericoides Symphyotrichum laeve officinale Taraxacum Thalictrum venulosum Trelease Erskine (Small ex Rydberg) rydbergii radicans var. Toxicodendron rafinesqueanum Schultes Viburnum americana Vicia Scientific name Potentilla Michaux macrocarpa Quercus canadensis (L.) Nuttall Shepherdia Picea glauca Pinus banksiana Lambert Poa annua L. 2018 Neufeld et al.: Manitoba’s alvars 245 Wetland X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Savannah Alvar type X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Shrubland

X X X X X X X X X Grassland S4S5 SU SU S4S5 S4S5 S4S5 S4S5 SU SU S4S5 SNR SU S4S5 S4S5 S4S5 S4S5 SU S4S5 SU S4S5 S4S5 S3S5 S2S4 S2S4 S3S5 S5 S4S5 S5 S4 S5 S4 S5 S5 Subnational G5 G5 G4G5Q G5 G5 G5 G5 G5 G4G5 G5 G3G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G4G5 G5 G4G5 G5 G5 G5 G5 G5 G5 G5 G5T5 G5 G5 Conservation status* Global Common name Ribbed Bog Moss Beard Moss Lesser Bird’s-claw Field Ragged Moss Golden Ragged Moss Campylium Moss Red Roof Moss Broom Moss Wavy- Rigid Beard Moss Moss Slender Candlesnuffer Elegant Beaked Moss Round-nerved Grimmia Moss Ciliate Hedwig’s Stairstep Moss Red-stemmed Feather Moss Thread Moss Clustered Tall Sickle Moss Norway Screw Moss Moss Twisted Fragile Frizzled Crisp Moss Hairy Screw Moss Wiry Moss Wiry Spring Dot Lichen Firedot Lichen Jungermann’s Six-celled Moss Dot Lichen Firedot Lichen Reindeer Lichen Vetch species Vetch species Violet Alexanders Golden Heart-leaved Alexanders Heart-leaved Wooden Soldiers Lichen Wooden Split-peg Lichen Ladder Lichen Mealy Pixie-cup Lichen British Soldiers

Species

(Hoffm.) Ahti (Hoffm.)

(Hedw.) J.R. Spence & H.P. Ramsay J.R. Spence & H.P. (Hedw.) (Schreb.) Hafellner Th. Fr. (Vahl) (Hedw.) Jenn. (Hedw.)

Wade A. E. Ach.) ex (Hoffm. Limpr. Web. Tuck. ) (Hedw.) Fleisch. (Hedw.) Hedw. (Hedw.) Loeske (Hedw.) (K. G. Hagen) Willd. (K. G. Hagen) Limpr. (Hedw.) Beauv. P. (Hedw.) (L.) Fr. in Drumm.) Limpr. Wils. (Hook. & sp. 1. ( continued sp. osses i c he n s able Schwaegr. (Hedw.) Aulacomnium palustre Barbula convoluta (C. Müll.) Schimp. in B.S.G Brachythecium campestre & Mohr) Schimp (Web. Brachythecium salebrosum Brachythecium Bryum sp. Campylium polygamum (Schimp.in B.S.G) C. Jens. Brid. (Hedw.) Ceratodon purpureus Dicranum polysetum Sw. Didymodon rigidulus Hedw. Bruch Encalypta procera pulchellum Eurhynchium Grimmia teretinervis Hedwigia ciliata Schimp. in B.S.G Hylocomium splendens (Hedw.) (Brid.) Mitt. schreberi Pleurozium Ptychostomum pseudotriquetrum Sanionia uncinata Syntrichia norvegica fragilis Tortella tortuosa Tortella Gaertn. et al. ruralis (Hedw.) Tortula T M Abietinella abietina L Biatora vernalis Caloplaca jungermanniae Cladonia botrytes Mycobilimbia sabuletorum Caloplaca holocarpa Hale & Culb. Cladina arbuscula (Wallr.) Scientific name Vicia Vicia spp. Viola Koch (L.) W.D.J. Zizia aurea Zizia aptera (A. Gray) Fernald Cladonia cariosa (Ach.) Cladonia cervicornis ssp. verticillata (Flörke ex Sommerf.) Cladonia chlorophaea Cladonia cristatella 246 The Canadian Field-Naturalist 2018 Wetland X X X X X X X X Savannah Alvar type X X X X X X X X X X X X X X X Shrubland

X Grassland SU SU S5 S4 S5 S4 SU S5 SU SU S3S5 SU S5 SU S2S4 SU S4 Subnational G5 G4G5 G5 G5 G5 G5 G5? G5 G5 G4G5 G5 G5 G5 G5 G5 G5 G5 Conservation status* Global Common name Red Threadwort Red Large-leaved Pixie Lichen Large-leaved Pebbled Pixie-cup Split-peg Lichen Sieve Lichen Rosette Pixie-cup Lichen Branched Pixie-cup Lichen Hooded Rosette Lichen Hoary Rosette Lichen Black-eyed Rosette Lichen Frosted Grain-spored Lichen Scaly Pelt Lichen Felt Lichen Easter Foam Lichen Lichen Wart Cumberland Rock-shield Pincushion Sunburst Lichen

Species (Gyelnik) Hale Nyl. (L.) Hoffm. (L.) Hoffm. (Nees) Warnst G. Merr . (Flörke ex Sommerf.) Zopf (Hoffm.) Th. Fr. ex Rieber Th. Fr. (Hoffm.) (Fr.) H. Olivier (Fr.) ) Vascular plants, bryophytes, and lichens observed in each type of alvar. Vascular ) (Weiss) Humb. (Weiss) (Ach.) Grognot (L.) Hoffm. (Ehrh. ex Humb.) Fürnr. (Tuck.) J. W. Thomson J. W. (Tuck.) 1. ( continued able iverworts T L Cephaloziella rubella *Global (NatureServe 2016) and subnational (Manitoba Conservation Data Centre unpubl. data) conservation status ranks. Scientific name Cladonia macrophyllodes Cladonia macrophyllodes Cladonia pyxidata Cladonia symphycarpa (Flörke) Fr. Peltigera praetextata Cladonia multiformis Cladonia pocillum J. R. Laundon Cladonia ramulosa (With.) Physcia adscendens Physcia aipolia Physcia phaea Körber regularis Sarcogyne Peltigera rufescens paschale Stereocaulon muralis Ach. Verrucaria Xanthoparmelia cumberlandia Xanthoria polycarpa 2018 Neufeld et al.: Manitoba’s alvars 247

Figure 3. Grazed grassland alvar at the Sylvan Alvar site. Photo: Nature Conservancy of Canada.

Figure 4. Shrubland alvar at the Clematis Alvar site. Photo: Nature Conservancy of Canada. 248 The Canadian Field-Naturalist 2018

Figure 5. At the Clematis Alvar site, trees are often present along the periphery where the alvar transitions into woodland. Photo: Nature Conservancy of Canada.

Figure 6. Shrubland alvar at the Marble Ridge Alvar site. Some of the scattered boulders support Gastony’s Cliffbrake (Pellaea gastonyi) or Western Dwarf Cliffbrake (Pellaea glabella ssp. occidentalis) or both. Photo: Nature Conservancy of Canada. 2018 Neufeld et al.: Manitoba’s alvars 249 than in grassland alvars, although the abundance of and mosses, with few forbs or shrubs and no trees. each varies among sites. Sites vary from flat to having These are low areas that grade into other alvar types. table-top limestone outcrops and scattered limestone They are often partly bordered by willow-dominated boulders. Drainage is restricted at these sites, which are swamps and marsh. Despite similar soil depths and periodically flooded. In the absence of rain, drought- cover as grassland alvars, these sites remain saturated like conditions were observed. enough to support wetland vegetation, but are not per- Savannah alvars (Figures 7 and 8) are similar to shrub­ manently flooded. It is unknown whether the difference land alvars in their patchy distribution of vegetation. is a result of increased water catchment from the sur- Soil depth is usually <5 cm, but frequently deeper in rounding topography or a difference in the degree of cracks and seams. Limestone pavement is frequent. drainage restriction by the underlying bedrock. Shrubs are dominant, followed by forbs, with gram- inoids less abundant. Unlike shrubland alvars, distri- Bedrock geology bution of trees is regular, although still amounting to Survey sites coincided with limestone bedrock from <60% cover, and tall shrubs can occur frequently. Bryo- the Jurassic, Permian, Devonian, Silurian, and Ordovi- phyte and lichen cover is variable and generally less cian geologic periods. Alvar was located only on Silu- dominant than in shrubland alvars. Like shrubland al- rian and Ordovician bedrock, which consist primarily vars, savannah alvars vary from being flat to having of dolomite (Manitoba Mineral Resources 2012a). scattered boulders or table-top outcrops, but are more The Clematis Alvar and two units of the Poplarfield frequently associated with the latter than shrubland al- Alvar occur on Silurian bedrock, which consists of mi- vars. These sites flood periodically and exhibit drought- critic, fossiliferous, stromatolitic, and biostromal do- like conditions; however, extremes in moisture vari- lomites, whereas the other alvars occur on Ordovician ability at sites with greater tree abundance are not as bedrock comprising various dolomites including argil- pronounced. laceous, nodular, and laminated dolomite (Manitoba Like grassland alvars, wetland alvars have nearly Mineral Resources 2012a). continuous vegetative cover, with soils about 5 cm deep Alvars occur on four Ordovician formations. The and occasional patches of exposed limestone pavement Marble Ridge Alvar site and the rest of the Poplarfield (Figure 9). They are dominated by wetland graminoids Alvar sites are primarily located within the western

Figure 7. Savannah alvar with White Spruce (Picea glauca) at the Poplarfield Alvar site. Photo: Nature Conservancy of Canada. 250 The Canadian Field-Naturalist 2018

Figure 8. Savannah alvar with Jack Pine (Pinus banksiana) at the Marble Ridge Alvar site. Photo: Nature Conservancy of Canada.

Figure 9. Wetland alvar at the Marble Ridge Alvar site. Photo: Nature Conservancy of Canada. 2018 Neufeld et al.: Manitoba’s alvars 251

Stony Mountain Formation and the East Arm Forma- sive species in Manitoba alvars represents a rare op- tion, whereas the Peguis and Sylvan Alvars fall into the portunity to prevent further establishment and maintain eastern Stony Mountain Formation and the Red River the exceptional biodiversity of these habitats. Formation (Manitoba Mineral Resources 2012a). Management and conservation context Significant species Alvars make up 0.3% (3934 ha) of the south Inter- Twenty-four globally, nationally, or provincially rare lake. Each alvar type supports its own complement of and uncommon species (NatureServe 2016; Manitoba plants and contributes uniquely to the biological diver- Conservation Data Centre unpubl. data) were docu- sity of Manitoba. The significance of alvar habitat and mented at survey sites during this study or previously the threats it faces across Canada have been extensive- by Caners (2011). Globally uncommon and provincially ly documented (Catling and Brownell 1995, 1999b; endangered Gastony’s Cliffbrake (Pellaea gastonyi Reschke et al. 1999; Catling 2014; Catling et al. 2014; Windham; Friesen and Murray 2015) and globally un- Brunton and Catling 2017). Protection and conservation common Grimmia Dry Rock Moss (Grimmia teretinerv- efforts in Manitoba should initially focus on preserving is Limpricht; Caners 2011) were observed growing on representatives of each type. In addition to supporting limestone cliffs and boulders at the Marble Ridge Alvar vascular plant species assemblages distinct from other sites. Vascular plant species assessed as provincially ecosystems in Manitoba, different types of alvar sup- uncommon or rare (Manitoba Conservation Data Cen- port a range of other species groups. For example, we tre unpubl. data) observed during this study include: observed grassland-obligate birds, a group undergoing Dwarf Western Cliffbrake (Pellaea glabella ssp. oc- steep population declines in North America (North cidentalis (E.E. Nelson) Windham), Rough Fescue American Bird Conservation Initiative 2016), on grass- (Festuca hallii (Vasey) Piper), Porter’s Chess (Bro- land alvars; Eastern Whip-poor-will (Antrostomus vo- mus porteri (J.M. Coulter) Nash), Wild White Onion ciferus) and Common Nighthawk (Chordeiles minor), (Allium textile A. Nelson & J.F. Macbride), Spring both threatened species (SARA Registry 2018a,b), have Birch (Betula occidentalis Hooker), Spike-oat (Avenu- been documented in shrubland and savannah alvars with la hookeri (Scribner) Holub), American Cow-wheat sparse vegetation (Manitoba Conservation Data Centre (Melampyrum lineare Desrousseaux), Large Indian unpubl. data). Alvars associated with inland cliffs, out- Breadroot (Pediomelum esculentum (Pursh) Rydberg), crops, and boulders, such as along Marble Ridge, pro- Smooth Sumac (Rhus glabra L.), and Dense Spikemoss vide a wide range of microhabitats not found in other (Selaginella densa Rydberg; Table 1). Six species of alvar types, and support a number of bryophytes that lichens observed during this study and six species of are expected to remain uncommon in the region (Can- bryophytes documented by Caners (2011) are also as- ers 2011). sessed as nationally or provincially rare or uncommon Approximately one third (1261 ha) of alvar in Man- (NatureServe 2016; Manitoba Conservation Data Cen- itoba occurs on privately owned land, with the remain- tre unpubl. data). der on public land including wildlife management ar- Six non-native plant species were observed in al- eas, community pastures, and undesignated provincial vars. Timothy (Phleum pratense L.) was observed often, Crown land. but never as a dominant species. Kentucky Bluegrass No alvar sites identified in this study are located (Poa pratensis L.) was observed in some grass-domi- within the boundaries of protected areas (IUCN Pro- nated alvars. Annual Bluegrass (Poa annua L.) was ob- tected Areas Classification level IV or higher; Manitoba served in some alvars, often occurring on sparsely veg- Conservation and Water Stewardship 2012b) or are pro- etated patches of shallow, bare soil. Garden Bird’s-foot tected from all types of development. A 2560-ha eco- Trefoil (Lotus corniculatus L.) was found on the peri­ system protection zone that encompasses most of the phery of two alvars and, at a third site, there were a Marble Ridge Alvar site has been proposed. few scattered plants on the alvar itself. Awnless Brome Approximately 12% of the Manitoba alvar habitat (Bromus inermis Leysser) and Creeping Bentgrass identified in this study falls under mining and/or quarry (Agrostis stolonifera L.) were each observed once in a leases (Manitoba Mineral Resources 2012b) and, thus, grazed alvar. may be exposed to habitat destruction from mining ac- Overall, it appears that non-native species in Manito- tivities. At the time of our survey, near-surface lime- ba alvars are infrequent, and invasive species that are stone had been commercially extracted immediately of high priority for detection and control in Manitoba adjacent to or within alvar communities at six locations. (Invasive Species Council of Manitoba 2018) are not Approximately 76% (2985 ha) of alvar habitat iden- currently present in these ecosystems. Non-native or tified in this study was being grazed at the time of the invasive plant species can result in reduced biodiversity survey or exhibited signs of having been grazed recent- and function in natural ecosystems and are becoming ly. Another 11% (432 ha) did not appear to be grazed by increasingly widespread in open habitats in the prairie domestic livestock. Most observed grazing animals provinces (Canadian Food Inspection Agency 2008; were cattle, but horses and bison were also observed. Sinkins and Otfinowski 2012; DeKeyser et al. 2013). Land use at the other locations (13%) could not be de- The relatively limited presence of non-native or inva- termined. Pre-European settlement grazing histories for 252 The Canadian Field-Naturalist 2018 the Interlake area are unclear (Henderson and Koper provided their expertise and support as members of the 2014), but grazing by large ungulates has likely always Manitoba Alvar Initiative Steering Committee. An ear- contributed to the disturbance regime of Manitoba al- lier version of this manuscript was reviewed by Nico- vars and may play an important role in maintaining las LaPointe and Melissa Grantham of NCC. The au- their openness, as it does in alvars elsewhere (Reschke thors gratefully acknowledge Richard Caners (Royal et al. 1999). However, current grazing management us- Alberta Museum) and Michele Piercey-Normore (Uni- ing livestock is unlikely to mirror historical patterns versity of Manitoba) for bryophyte and lichen identi- (Henderson and Koper 2014), and grazing at incom- fication, respectively. Our thanks to reviewers Daniel patible frequencies, intensities, or durations may result Brunton and Pauline Catling, whose comments greatly in alterations to species composition and facilitate the improved the manuscript. spread of non-native species (Reschke et al. 1999). No evidence of recent natural fire, an important eco- Literature Cited logical requirement of many alvar habitats (Catling and Brunton, D.F. 1988. The Clay Bank Alvar. Trail & Landscape Brownell 1998; Catling et al. 2002; Jones and Reschke 22: 53–65. Accessed 21 January 2018. http://www.biodiver 2005; Catling 2009b), was observed in or near any of sitylibrary.org/item/202202#page/23/mode/1up. the alvars. Trembling Aspen (Populus tremuloides Mi- Brunton, D.F., and P.M. Catling. 2017. Thematic collection: chaux) encroachment was observed at some locations alvars in Canada. Canadian Field-Naturalist 131: 75–79. in the Clematis Alvar and Poplarfield Alvar sites. Long- https://doi.org/10.22621/cfn.v131i1.1962 term fire suppression is probably negatively impacting Canadian Food Inspection Agency. 2008. Invasive alien the ecological integrity and biodiversity of alvar habitat plants in Canada – Technical Report. CFIA. Ottawa, Ontar­ io,­ Canada. Accessed 30 January 2018. http://epe.lac-bac.gc.ca/ here, as it is in other open habitats in southern Manitoba 100/206/301/cfia-acia/2011-09-21/www.inspection.gc.ca/ (e.g., Koper et al. 2010) and throughout North America. english/plaveg/invenv/techrpt/techrese.shtml. The current mix of public and private land owner- Caners, R.T. 2011. Saxicolous bryophytes of an Ordovician ship, history of fire suppression, and the economic po- dolomite escarpment in Interlake Manitoba, with new species­ tential of alvars for grazing and mineral resources high- records for the province. Canadian Field-Naturalist 125: light the need for the involvement and cooperation of a 327–337. https://doi.org/10.22621/cfn.v125i4.1261 range of stakeholders, including industry and private Catling, P.M. 2009a. Composition, phytogeography, and relict landowners, in alvar conservation. status of the vascular flora of alvars and cliff tops southwest of Great Slave Lake, Northwest Territories, Canada. 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Faunal surveys to further assess the biodiversity of 249. https://doi.org/10.22621/cfn.v128i3.1602 these sites are also needed. The selection of appropriate Catling, P.M., and V.R. Brownell. 1995. A review of the al- conservation management options in Manitoba requires vars of the Great Lakes region — distribution, floristic com- full investigation of the relation between the ecological position, biogeography and protection. Canadian Field-Nat- integrity of alvar habitat and ecological processes, such uralist 109: 143–171. Accessed 21 January 2018. http://bio as grazing and fire suppression. diversitylibrary.org/page/35456991. Catling, P.M., and V.R. Brownell. 1998. Importance of fire in alvar ecosystems — evidence from the Burnt Lands, east- Acknowledgements ern Ontario. Canadian Field-Naturalist 112: 661–667. Ac- A grant from the Province of Manitoba to the Nature cessed 21 January 2018. http://biodiversitylibrary.org/page/ Conservancy of Canada (NCC) supported NCC staff. 34258017. 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