the Biological Survey
About the Canadian Fauna
Arthropods of Canadian Grasslands Prospectus
Prepared in 2002 on behalf of the Biological Survey by:
Joseph D. Shorthouse,
Department of Biology, Laurentian University, Sudbury, Ontario
Les prairies sont un des principaux biomes canadien. La plus grande étendue de cet habitat couvre la portion sud des provinces des prairies canadiennes. Des habitats similaires se retrouvent aussi du Yukon jusqu’à l’est de l ’Ontario. Les prairies du Canada ont été durement exploitées pour l’agriculture et la survie de ces écosystèmes est maintenant menacée. Malgré l’utilisation intensive de cet habitat par les humains, nos connaissances sur la biodiversité, l’écologie et les impacts sur les communautés vivantes reliés au changement dans ces prairies sont très limités. Ce manque de connaissances est d’autant plus important chez les insectes et autres arthropodes, qui sont les groupes les plus diversifiés, abondants et écologiquement importants dans les prairies. Le projet sur les arthropodes des prairies canadiennes de la Commission biologique du Canada est un effort nationale majeur pour répondre à ce manque de connaissances.
Les objectifs à long terme de ce projet sont de répondre à trois questions majeures:
Pour répondre à ces questions, la participation de plusieurs collaborateurs conduisant des études systématiques et écologiques dans les prairies canadiennes sera indispensable. L’échantillonnage et le travail sur le terrain dans une variété d’habitats de prairies faciliteront les études taxonomiques des arthropodes associés à ces habitats. La recherche en systématique est essentielle pour fournir les informations de base qui pourront par la suite être combinées à des études sur l’écologie ou autres études appliquées. Des programmes d’échantillonnages standardisés dans des habitats sélectionnés fourniront des données quantitatives sur les populations des arthropodes. Ces données serviront à l’analyse des similarités et différences parmi les communautés d’arthropodes provenant de différentes regions et de differents types de prairies. Étant donné leurs implications dans le développement de l’agriculture dans l’ouest canadien, les prairies fournissent un excellent système pour étudier les impacts des activités humaines sur un écosystème relativement simple. De plus,elles perme ent d’étudier les effets potentiels à long terme de facteurs comme le changement climatique.
Les produits et applications de ce projet seront diversifiés. La recherche sur la diversité et l ’écologie des arthropodes fournira une source à long terme de spécimens et de données qui pourront servir pour de futures projets sur la biologie des arthropodes des prairies.Les publications sur la biodiversité des arthropodes des prairies,sur l ’écologie des arthropodes d ’habitats sélectionnés et sur les interactions entre les activités humaines et les arthropodes fourniront des moyens visibles de disséminer les connaissances acquises lors de ce projet. Lorsque ces connaissances sur la systématique et l ’écologie des arthropodes des prairies seront en place,il y aura plusieurs opportunités pour de futures utilisations de ces données pour des études appliquées comme la conservation d’habitats, le contrôle des effets de l’agriculture, des feux, du changement climatique et autres changements sur l ’habitat.
Avec la conscience grandissante du publique sur la crise de biodiversité, la communauté scientifique est hautement sollicitée pour comprendre et préserver les écosystèmes. Au même moment, les obligations internationales du Canada demandent que la flore et la faune de nos frontières soient cataloguées, contrôlées et protégées.Il y a donc un besoin urgent de connaître la biodiversité des arthropodes des prairies, qui ont, pour la majorité, un rôle encore inconnu dans ces importants écosystèmes. La Commission biologique du Canada est l ’organisme le mieux placé pour coordonner ce grand projet.
The Biological Survey of Canada (Terrestrial Arthropods) was established in 1977 by the Entomological Society of Canada to help characterize the insect fauna of Canada and coordinate national initiatives in taxonomic, faunistic and ecological entomology. The impetus for this agency was the concern that less than half the estimated 67,000 species of insects, spiders, mites and their relatives found in Canada have even been described; the ecological roles are known for an even smaller percentage. Since 1980,the Survey has been associated with the Canadian Museum of Nature. Initiatives of the Survey are coordinated by a Scientific Committee, comprised of 18-20 entomologists from across Canada, working in conjunction with the Survey Secretariat (headed by Dr. H.V. Danks). Over 20 books have been produced by the Survey including Arctic Arthropods, Insects of Peatlands and Marshes in Canada, Canada and its Insect Fauna, and most recently (1997), the 1034-page volume Insects of the Yukon.
The Arthropods of Canadian Grasslands Project will be the largest and most ambitious undertaken by the Survey. The project will involve numerous collaborating researchers and will generate products in a variety of formats. We envisage major volumes on the biodiversity of grassland arthropods, and on the ecological relationships of arthropods in selected grassland habitats, both pristine and human-modified. Electronic databases will allow new faunistic and ecological data to be incorporated from ongoing studies of the fauna. A Project web site (www.biology.ualberta.ca/bsc/english/grasslands.htm) and publication of an annual Grasslands Newsletter help coordinate researchers and their projects.
Trees are generally not associated with prairie grasslands because of unsuitable growing conditions and those present are usually stressed. However, stands of trees are found in various regions of the prairies where they owe their existence to sufficient groundwater supply, effects of elevation, or protection from fire. For example, forests in the Cypress Hills of Alberta and Saskatchewan owe their presence to the effects of topographic relief, while tall grass prairies and savannas in Manitoba and Ontario have a tree cover that results from sufficient groundwater. A distinctive feature of some prairies and the aspen parkland, is the riverine forests of broadleaf deciduous tree species such as Populus deltoides (cottonwood), Acer negundo (Manitoba maple) Salix interior (sandbar willow) and Salix amygdaloides (peach-leaved willow). These trees dominate the river margins, floodplains and upper-bank sandbars.
The prairie biome of Canada is found in southern Alberta, Saskatchewan and Manitoba and comprises one of the country’s five major biomes. Prairie grasslands cover about 5% of Canada’s land area and are associated with an extreme continental climate. Winters are normally cold and summers hot, annual temperature range is large, and a negative moisture index with summer moisture stress is typical. Our prairie grasslands are found in an arc that stretches to the east of the Rocky Mountains in Alberta, north to near Edmonton then southeast towards the Manitoba-Ontario border (Figs. 1, 2). They are bounded to the west and north by aspen parkland and continue in the south across the border with the United States. Less extensive and discontinuous prairie-type grasslands also occur in British Columbia (Fig. 3), northwestern Alberta, the Yukon Territory, and the Great Lakes region of Ontario. The dominant types of grasslands in this biome are described in Appendix 1.
Scope of the
There is an integral ecological connection between grassland ecosystems and the aquatic systems that are associated with them. For this reason, studies of selected aquatic ecosystems will be included in the project. Prairie sloughs, potholes and associated wetlands are a major source and sink of water for grassland communities, and provide habitat for species that either inhabit terrestrial grasslands for part of their life cycle, or have close interactions with terrestrial species. Because of the importance of riverine forests in defining the overall species diversity in grasslands, the riparian fauna of rivers in the Canadian prairies will also be considered.
These questions define the long-term objectives of the Grasslands Project. These objectives will, in turn, be achieved by addressing short-term objectives defined in this document.
Given the longstanding importance of grasslands to Canadian agriculture, and the recent realization of their importance in biodiversity and conservation, it is not surprising that there is a body of existing research on the arthropods of Canadian grasslands. The Grasslands Project will build on this foundation.
Many entomologists affiliated with Agriculture Canada Research Stations, other government agencies or universities have undertaken studies of arthropods in Canadian grasslands. Reference collections have been assembled at many of these institutions as well as at the Canadian National Collection in Ottawa, and serve as important resources for researchers associated with this project. In addition to the data contained in collections, studies by individual researchers and some larger scale syntheses have resulted in a number of publications on the arthropods of Canadian grasslands.
The species diversity and faunistics of some grassland arthropod taxa have been more intensively studied than others. For example, the leafhoppers (Hemiptera: Auchenorrhyncha) have been the subject of numerous studies across the range of grassland types (e.g., Hamilton 1994, 1995, 1997, Whitcomb et al 1994) and other Hemiptera are also well characterized (e.g., Scudder 1993). There is also relatively complete information on the grasshoppers (Orthoptera) (e.g., Brooks 1858). In contrast, faunistic studies of grassland Diptera have been limited to only a few families (e.g, Boucher and Wheeler 2001).
Multi-taxon inventories using standardized sampling methods have produced species lists and analyses of selected taxa in localities such as the Okanagan Valley, British Columbia (Blades and Maier 1996) and Canadian Forces Base Suffield in southern Alberta (Finnamore 1998, Finnamore and Buckle 1999).
Directed ecological studies have examined the effects of fire and other factors on grassland arthropod communities. Roughley (2001) studied post-fire colonization of tall grass prairie in Manitoba and White (2001) examined the effects of fire on arthropods in palouse grasslands. Evans (1988) studied the effect of fire and other habitat changes on grasshopper populations in tall grass prairies.
However, except for pest species, we still know surprisingly little about the arthropod fauna of Canada’s grasslands. We do not know how many undescribed or unrecorded species are still to be found in the remaining pristine grasslands, nor do we know which species are threatened by human activities. As well, little is known about the ecological role of arthropods that have survived and adapted to lands converted to agriculture. The accumulation of available information on the diversity of grassland arthropods, as well as other taxa, is necessary to permit analyses of large-scale historical patterns and changes in the fauna.
Rationale for a
Synthesis on Grassland Arthropods
Ecology of Grassland Arthropods
Grasslands are of great interest from a biogeographic point of view. This biome was persistent in North America during Pleistocene glaciations and many grassland species have an uninterrupted history of survival in this habitat through the Quaternary. Grasslands may have been persistent in glacial refugia such as Beringia during the Pleistocene as well; this has implications not just for the survival of isolated populations of arthropods there, but for the dispersal of Palearctic species into North America. At the other end of the scale, many of our current grassland habitats, especially at the eastern and western limits of their range, exist as isolated pockets. Studying the distribution of arthropods associated with these disjunct grasslands may help us to understand the history of these sites.
Grassland habitats provide a number of advantages to the study of arthropod ecology. Grasslands tend to have simpler trophic webs than forests or aquatic systems. Consequently, studies of species interactions or the effects of abiotic factors on species ecology and distribution are facilitated. Grasslands have a more two-dimensional structure than forests or lakes, which allows observation and measurements across a greater range of the habitat.
Because grassland habitats have characteristic dominant plant species that vary from site to site, it is relatively easy to establish relationships between particular plant species or communities and their associated arthropod assemblages. This permits detailed studies of plant-pollinator or plant-herbivore associations, and interactions within the assemblage of arthropods associated with particular plants or communities.
Restoration of Grassland Ecosystems
Oak and pine savannas once covered 1,200 km2 on sand plains in southwestern Ontario. Most of this ecosystem has been destroyed with only a few remaining tracts in southwestern Ontario. Similarly, alvar grasslands in the Great Lakes region have been reduced to a few small remnants and The Nature Conservancy considers most alvar types globally imperiled as a result of livestock grazing, limestone quarrying and urbanization.
The same pattern of human settlement and ecosystem alteration for food production has occurred on most of the palouse grasslands in British Columbia. Factors such as fire suppression, urban sprawl, orchards, vineyards, introduced species and cattle grazing have reduced the palouse grasslands in the Okanagan Valley to a few small vulnerable pockets.
The continued existence of the remaining tracts and remnants of Canada’s grasslands has become more important as efforts intensify to conserve ecosystems and the species they contain. Coupled with the need for increased research on prairie ecosystems is a greater urgency for an updated synthesis of information on the ecology of grasslands. As with all terrestrial ecosystems, arthropods play a fundamental role in the functioning and productivity of grassland ecosystems and this is why defining these roles will be a major objective of this project.
Monitoring the Effects of Human Activities and Climate Change
Settlers plowed under the original flora of the prairies and replaced this endemic flora with introduced crops of Eurasian steppe origin, many of which were grasses closely related to the native species. As a result, native insects were able to switch with ease from wild grasses to cereal crops. For example, the native wheat stem sawfly moved from native grasses to wheat, as did many species of grasshoppers, wireworms, cutworms and armyworms.
Such a small proportion of the original grasslands remain that that we will never know whether or not the assemblages they support today resemble those present prior to European settlement. However, there is little doubt that the native arthropod fauna on the whole has been diminished. The insect fauna of cultivated fields is depauperate with major taxa such as spiders, ants and Hemiptera rare or nonexistent. Grazing by cattle has also selectively altered the relative abundance of many prairie plants, and with them populations of associated insects. Few species of insects have likely become extinct because of settlement, but many have been reduced to small populations inhabiting scattered refuges. One of the objectives of this project is to help locate, study and hopefully preserve many of these refuges.
Because of the relatively recent settlement history in Canadian grasslands, we have data on the temporal and spatial scale of these habitat changes. This facilitates study the effects of known, long-term changes on a native habitat. The persistence of isolated patches of native prairie communities also provides the opportunity to study species survival and interactions in ecological islands of varying sizes and degrees of disturbance. Finally our altered grasslands provide an excellent opportunity for the study of interactions between introduced, mostly European species and native species.
Another type of change that may affect grasslands more than many other habitats is global climate change. Because of the already harsh continental climate and moisture limitation of grasslands, any exacerbation of these conditions will place additional selection pressures on these ecosystems. Arthropods would be among the first organisms to respond to these additional stresses and, as such, would serve both as indicators of habitat change and study organisms for the ability of ecosystems to respond to changes.
Studies on systematics and faunistics of selected taxa of grassland arthropods will make extensive use of the resources already housed in collections. Proper attention to label data of material added to collections will facilitate the use of the specimens in these studies (Wheeler et al. 2001). Structured sampling programs will provide specimens of use in systematic studies as well as in ecological investigations. Targeted collecting may also be necessary to obtain sufficient specimens and ecological data of taxa not normally obtained using standard techniques. Such taxa include parasites or parasitoids for whom host data are required and herbivores that are internal feeders (gall inhabitants, leaf miners, stem borers) or for whom host plant identification is required.
At the species level, knowledge of regional diversity will allow workers to identify species at risk, which will in turn help to identify areas that should be targeted for conservation. This knowledge will also facilitate informed decisions on land-use planning, particularly in cases where the choice between multiple alternatives has implications for species or habitats at risk. In situations where land use decisions have already been made, arthropods will prove valuable in monitoring ecosystem health, given their broad range of responses to change. Finally, in cases where poor decisions in the past have resulted in degraded ecosystems, knowledge of the role of arthropods will be absolutely crucial in restoration attempts.
There are a variety of human impacts to which arthropods respond more quickly and more predictably than other taxa. Thus, understanding the responses of grassland species to changes will allow us to interpret and predict the effects of fire, grazing, etc. Greater understanding of grassland arthropod dynamics will permit more accurate predictions of the potential effects of newly recognized pest species, or newly introduced biological control agents.
The fieldwork and laboratory research of individual collaborators in the project will often be partly supported by research grants from government agencies (e.g., NSERC) or their home institution (e.g., museums, government laboratories). However, additional sources of public and corporate funding will be necessary. It is increasingly evident that a major cost of biodiversity research is in the preparation, curation and maintenance of specimens and in the construction of databases to allow the specimen data to be accessible for analysis. The importance of this component of the research is, unfortunately, vastly under appreciated by most funding agencies. This means that other sources must be sought to support the personnel engaged in these duties.
The Survey and Grasslands Subcommittee will explore sources of funding through federal and provincial government agencies, conservation agencies and foundations, resource and utility industries, agricultural organizations, etc. It will likely be more feasible to seek group funding for collaborative efforts on defined subsets of the overall project. Although some mechanisms currently exist for funding collaborative research (e.g., NSERC strategic grants and collaborative grants) additional sources, including non-traditional avenues will be sought. The possibility of the Survey applying for block funding which could then be distributed to individual researchers will be explored. There will be considerable costs associated with the publication of the large volumes resulting from this project. Planning must begin soon to ensure sufficient contributions by sponsors and supporting agencies are in place to produce and distribute these volumes.
Anderson, T.W., R.W. Mathewes and C.E. Schweger. 1989. Holocene climatic trends in Canada with special reference to the Hypsithermal interval. Pp. 520-528 In R.J. Fulton (Ed.). Quaternary Geology of Canada and Greenland. Geology of Canada No. 1. Geological Survey of Canada, Ottawa.
Blades, D.C.A. and C.W. Maier. 1996. A survey of grasslands and montane arthropods collected in the southern Okanagan region of British Columbia. Journal of the Entomological Society of British Columbia 93: 49-73.
Boucher, S. and T.A. Wheeler. 2001. Diversity of Agromyzidae (Diptera) in disjunct grasslands of the southern Yukon Territory. The Canadian Entomologist 133: 593-621.
Brooks, A.R. 1958. Acridoidea of Southern Alberta, Saskatchewan and Manitoba (Orthoptera). The Canadian Entomologist, Supplement 9: 3-32.
Danks, H.V. 1996. How to assess biodiversity without wasting your time. A brief from the Biological Survey of Canada (Terrestrial Arthropods). Biological Survey of Canada Document Series No. 5.
Danks, H.V. and N.N. Winchester. 2000. Terrestrial arthropod biodiversity projects – building a factual foundation. A brief prepared by the Biological Survey of Canada (Terrestrial Arthropods). Biological Survey of Canada Document Series No. 7.
Evans, E.W. 1988. Grasshopper (Insecta: Orthoptera: Acrididae) assemblages of tallgrass prairie: influences of fire frequency, topography, and vegetation. Canadian Journal of Zoology 66: 1495-1501.
Finnamore, A.T. (Editor). 1996. The SAGE Project: A workshop report on terrestrial arthropod sampling protocols for graminioid ecosystems. EMAN and Partners Publications. www.cciw.ca/eman-temp/reports/publications/sage
Finnamore, A.T. 1998. Results from grasslands: aculeate wasps from Canadian Forces Base Suffield (Hymenoptera: Chrysididae, Vespoidea, and Apoidea: Sphecidae). Newsletter of the Biological Survey of Canada (Terrestrial Arthropods) 17: 44-57.
Finnamore, A.T., V.M. Behan-Pelletier and N.N. Winchester. 1998. Protocols for measuring biodiversity: Arthropod monitoring in terrestrial ecosystems. EMAN and partners publications. www.cciw.ca/eman-temp/reports/publications
Finnamore, A.T. and D. Buckle. 1999. Arthropod component report. The stinging wasps (Hymenoptera: Chrysidoidea, Vespoidea, Apoidea) and spiders (Araneae). Canadian Forces Base Suffield National Wildlife Area. Wildlife Inventory. The Provincial Museum of Alberta. 197 pp.
Hamilton, K.G.A. 1994. Leafhopper evidence for origins of northeastern relict prairies (Insecta: Homoptera: Cicadellidae). Pp.61-70 In R.G. Wickett, P.D. Lewis, A. Woodliffe and P. Pratt (Eds.). Proceedings of the Thirteenth North American Prairie Conference. Preney Print & Litho, Windsor.
Hamilton, K.G.A. 1995. Evaluation of leafhoppers and their relatives (Insecta: Homoptera: Auchenorhyncha) as indicators of prairie preserve quality. Pp. 211-226 In D.C. Harnett (Ed.). Proceedings of the Fourteenth Annual North American Prairie Conference: Prairie Diversity. Kansas State University, Manhattan.
Hamilton, K.G.A. 1997. Leafhoppers (Homoptera: Cicadellidae) of the Yukon: dispersal and endemism. Pp. 337-375 In H.V. Danks and J.A. Downes (Eds.). Insects of the Yukon. Biological Survey of Canada (Terrestrial Arthropods), Ottawa.
Knapp, A.K.. J.M. Blair, J.M. Briggs, S.L. Collins, D.C. Hartnett, L.C. Johnson and E.G. Towne. 1999. The keystone role of bison in North American tallgrass prairie. Bioscience 49: 39-50.
Lehmkuhl, D.M. 1980. Temporal and spatial changes in the Canadian insect fauna: patterns and explanation, the Prairies. The Canadian Entomologist 112: 1145-1159.
Marshall, S.A., R.S. Anderson, R.E. Roughley, V.M. Behan-Pelletier and H.V. Danks. 1994. Terrestrial arthropod diversity: Planning a study and recommended sampling techniques. A brief. Bulletin of the Entomological Society of Canada 26(1) (Supplement).
Matthews, J.V., Jr. 1979. Tertiary and Quaternary environments: historical background for an analysis of the Canadian insect fauna. Pp. 31-86 In H.V. Danks (Ed.). Canada and its insect fauna. Memoirs of the Entomological Society of Canada 108: 1-573.
Matthews, J.V., Jr. 1982. East Beringia during late Wisconsin time: A review of the biotic evidence. Pp. 127-156 In D.M. Hopkins, J.V. Matthews Jr., C.E. Schweger and S.B. Young (Eds.). Paleoecology of Beringia. Academic Press, New York.
Moss E.H. 1952. Grassland of the Peace River region, western Canada. Canadian Journal of Botany 30: 99-123.
Ritchie, J.C. 1975. The late-Quaternary vegetational history of the Western Interior of Canada. Canadian Journal of Botany 54: 1793-1818.
Roughley, R.E. 2001. Tallgrass prairie and the use of fire as a biodiversity and conservation and management tool on the St. Charles Rifle Range, Department of National Defence, Winnipeg, Manitoba. 81 pp.
Scudder, G.G.E. 1993. Geographic distribution and biogeography of selected species of xeric grassland-adapted Nearctic Lygaeidae in western North America (Insecta: Heteroptera). Pp. 75-113 In G.E. Ball and H.V. Danks (Eds.). Systematics and entomology: diversity, distribution, adaptation, and application. Memoirs of the Entomological Society of Canada 165: 1-272.
Turnbull, A.L. 1979. Recent changes to the insect fauna of Canada. pp 180-194 In H.V. Danks (Ed.). Canada and its insect fauna. Memoirs of the Entomological Society of Canada 108: 1-573.
Wheeler, T.A., J.T. Huber and D.C. Currie. 2001. Label data standards for terrestrial arthropods. A brief prepared by the Biological Survey of Canada (Terrestrial Arthropods). Biological Survey of Canada Document Series No. 8.
Whitcomb, R.F., A.L. Hicks, H.D. Blocker and D.E. Lynn. 1994. Biogeography of leafhopper specialists of the shortgrass prairie: evidence for the roles of phenology and phylogeny in determination of biological diversity. American Entomologist 40: 19-35.
White, K.M. 2001. The effect of a grassland fire on a prairie arthropod community. Arthropods of Canadian Grasslands Newsletter 7: 21-25.
Classification and Distribution of Canadian Grasslands
Dry Mixed Grass Prairie (‘Short Grass’ Prairie) (Fig. 2) occurs in southeastern Alberta and southwestern Saskatchewan where rainfall and evaporation are less favourable. Dominant grasses are Bouteloua gracilis (blue grama) Buchloë dactyloides (buffalo grass) and Stipa comata (needle and thread). In seriously overgrazed areas, Opuntia polyacantha (prickly pear) and Artemisia frigida (pasture sage) are common. The term ‘short grass prairie’ is often used to describe this grassland type; however, some authors point out that this term does not strictly apply in Canada because these areas are actually xeric mixed grasslands which have been overgrazed to the point that short grass species dominate.
Mixed Grass Prairie (Fig. 2) occurs in southern Alberta and Saskatchewan with Stipa comata (needle and thread) Festuca altaica (northern rough fescue), Festuca occidentalis (Idaho fescue), Danthonia parryii (Parry’s oat grass) and Danthonia intermedia (wild oat grass) being the dominant grasses. Outliers of mixed grass prairie are also found in the Peace River district of northwestern Alberta where Stipa spartea (porcupine grass) dominates.
Tall Grass Prairie (Fig. 2) is found only in southern Manitoba, the Rainy River-Fort Frances area of northwestern Ontario and southwestern Ontario where precipitation and groundwater are sufficient to allow trees such as oaks and poplars to become established, but frequent fire and herbivory keep them from encroaching on the open areas. Canadian areas of tall grass prairie are extensions of the so-called Prairie Peninsula of the USA. Dominant grasses in Manitoba and Ontario tall grass sites include Andropogon gerardii (big bluestem), Panicum virgatum (switchgrass), Schizachyrium scoparium (little bluestem) and Spartina pectinata (cord grass). Non-grass species such as sedges and composites are diverse and sometimes dominant in tall grass prairies.
Fescue Grassland occurs in three well-defined areas (Fig. 2). The largest is found in a broad swath along the moister, northern border of mixed grass prairie in Alberta west of Edmonton, across central Saskatchewan and Manitoba to just east of Winnipeg. This ecotone, the Aspen Parkland ecotone, forms the transition between the boreal forest of the north and the grasslands to the south and is characterized by groves of Populus tremuloides (aspen poplar). Fescue grassland is also found in the Cypress Hills of southeastern Alberta and southwestern Saskatchewan and the foothills of the Rocky Mountains in southwestern Alberta. The third area is in sub-boreal and boreal regions, ranging from the northern Rocky Mountains in Alberta westward through British Columbia and north to the Yukon. The dominant grass in the fescue grasslands of the Aspen Parkland ecotone is Festuca campestris (rough fescue). Festuca altaica (northern rough fescue) is dominant in the other areas of fescue grassland.
Bunch Grass or Palouse Grasslands are grasslands of the southern interior of British Columbia. This unique region is a northern extension of the intermontane grassland area of the western United States. These discontinuous grasslands occur in several of the southern interior valleys of British Columbia (e.g., Kettle Valley; Okanagan Valley, Similkameen River Valley, Thompson River Valley, Nicola River Valley and adjacent plateau areas, middle Fraser and lower Chilcotin River valleys). Smaller palouse grasslands occur in the Kootenay and Columbia River valleys in southeastern British Columbia. The dominant grasses in these areas include Agropyron spicatum (bluebunch wheatgrass), Poa secunda (Sandberg’s bluegrass), P. cusickii (Cusick’s bluegrass), Koeleria cristata (June grass), Stipa comata (needle-and-thread grass), Festuca scabrella (rough fescue) and Festuca idahoensis (Idaho fescue). Trees associated with this region include Pseudotsuga menziesii var. glauca (Douglas fir) and Pinus ponderosa (Ponderosa pine) and the shrub Artemisia tridentata (sagebrush). Three dominant climax types, defined by a combination of temperature, precipitation, altitude and latitude are recognized within these grasslands. Lower grasslands are hot and dry sagebrush-bunchgrass in the valley bottoms; middle grasslands are a less arid band of steppe above the lower grassland; upper grasslands are cooler, moister steppe that extends onto the plateau. Extreme overgrazing in all three grassland areas has resulted in invasion by weedy species such as Bromus tectorum (cheatgrass) and Centaurea species (knapweed)
Savannas and Grassland Alvars represent the eastern outliers of the prairie grasslands in Manitoba and southern Ontario. Savannas are characterized by an understory dominated by prairie-associated grasses, with an open forest of oaks (Quercus spp.) or pines (Pinus spp.). Alvar grasslands and alvar savanna grasslands are similar in appearance to savannas. Savannas and alvars in the Great Lakes region of Ontario have a number of plant species typical of tall grass and mixed prairies including Andropogon gerardii (big bluestem), Schizachyrium scoparium (little bluestem), Sporobolus heterolepis (prairie dropseed) and Panicum virgatum (switchgrass). The major difference between savannas and alvars and the western grasslands is the substrate; alvar grasslands are characterized by a thin layer of soil overlying limestone bedrock while Ontario savannas are associated with well-drained sandy soils. The physical nature of these substrates limits the growth of trees and contributes to the open, prairie-like nature of these habitats.
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Prepared in 2002 on behalf of the Biological Survey by:
Joseph D. Shorthouse,
Department of Biology, Laurentian University, Sudbury, Ontario
Biological Survey of Canada
Canadian Museum of Nature
P.O. Box 3443, Station "D", Ottawa, Ontario K1P 6P4 Canada
This page last updated 02/03/2010