MONITORING THE CONSERVATION OF GRASSLAND HABITATS,
PRAIRIE ECOZONE, CANADA
DAVID A. GAUTHIER1∗ and ED B. WIKEN2
1 Canadian Plains Research Center, University of Regina, Canadian Plains Research Center,
University of Regina, Regina, Saskatchewan S4S 0A2;
2 National Habitat Status Program, Wildlife Habitat Canada, 7 Hinton Avenue North, Ottawa, ON,
Canada, K1Y 4P1; e-mail: [email protected]
(∗ author for correspondence, e-mail: [email protected])
Abstract. The Prairie Ecozone contains 5% of Canada’s land area and represents 16% of the Great
Plains of North America. Current estimates indicate that 25–30% of original Canadian grassland
habitats remain, largely concentrated in southeastern Alberta and southwestern Saskatchewan with
fragments distributed throughout southern Manitoba. The size, distribution and condition of native
grasslands serve as valuable indicators of the ecological integrity and the sustainability of those
landscape types. With so little native grasslands remaining, areas that conserve grasslands serve
as core sites for indicators such as gaps in ecosystem and wildlife habitat protection, i.e. which
ecosystems are well-represented, poorly represented or have no representation. Such gap analyses
helps to determine where protection efforts need to be placed in the future. Overall, about 3.5% of
the Prairie Ecozone of Canada is under some form of conservation area status. This paper reports,
relative to the ecoregions and political jurisdictions of the Prairie Ecozone, on the amount and distribution of various types of conservation areas and native grasslands. Relationships between the
occurrence of conservation areas and grasslands are presented. Implications for conservation area
planning and management are discussed within regional, national and international contexts. The
issue of which characteristics of conservation areas should be assessed and monitored to address
conservation objectives for sustainability is also discussed.
Keywords: grasslands, habitats, monitoring, prairie ecozone
1. Introduction
This paper provides an overview of ecosystem, land cover and conservation area
databases useful for assessing and monitoring the status of grasslands within the
Prairie Ecozone of Canada. It presents data from comprehensive databases for land
cover and conservation areas at various ecological scales to address questions such
as:
(a) How much of the native grasslands remain?
(b) Which areas of the Prairies are under some form of conservation management?
(c) How much of the native grasslands are currently conserved?
(d) What is the extent of fragmentation of native grassland habitats?
Such questions are critical in assessing the status of ecosystems and in determining
proper objectives and indicators.
Environmental Monitoring and Assessment 88: 343–364, 2003.
© 2003 Kluwer Academic Publishers. Printed in the Netherlands.
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DAVID A. GAUTHIER AND ED B. WIKEN
Figure 1. Administrative jurisdictions and ecological regions of North America (Source: Wiken and
Gauthier, 1998).
Data at multiple scales are available for monitoring of grasslands. General data
are first presented at the level of the North American continent, then in terms of the
Great Plains of North America, the Prairie Ecozone of Canada, the Prairie Ecozone
of Saskatchewan, the Mixed Grassland Ecoregion of Saskatchewan and, finally, one
ecodistrict within the Mixed Grassland Ecoregion. In addition, some historical data
is presented to indicate that there are opportunities for mining of past data that are
very relevant to today’s concerns.
2. North American Perspective
Over 90 administrative divisions from federal to the level of states and provinces
and 52 coarse-scale ecological regions subdivide the North American continent
(Figure 1). The North American Great Plains extend over the widest latitudinal
range of any ecological region on the continent (CEC, 1997; Wiken and Gauthier,
1998). Three Canadian provinces, 18 U.S. states and 3 Mexican states have responsibilities for Great Plains. The greatest amount of the Great Plains of N.A. (approximately 80%) occurs in the United States, accounting for 29% of that country’s
land area. Mexico contains the least amount (4%) of the Great Plains, restricted to
5% of the country’s land area. Canada’s responsibilities relate to the 16% that is
northern Great Plains constituting about 5% of the landmass of Canada (Gauthier
and Wiken, 1998).
MONITORING PRAIRIE HABITATS, CANADA
345
Figure 2. National, provincial and state parks for ecological regions of North America (Source:
Gauthier and Wiken, 2002).
3. North American Conservation Areas
Work is on-going to develop a comprehensive, integrated North American Conservation Areas Database (NCAD)1. Figure 2 shows results for national, provincial
and state parks relative to coarse scale ecological regions and to administrative
jurisdictions for most areas of continental North America. Some of the databases
used to develop NCAD use only centroids as location reference points, some lack
polygon boundaries, and some do not code according to standardized conservation
area categories. All of these factors create difficulties for standardizing information across jurisdiction and ecological boundaries. Work is on-going to address
those problems. Nonetheless, current country databases for North America provide
useful indicators for assessing and monitoring, e.g. number of conservation areas,
size of conservation areas. Useful subsets of NCAD can be created. For example,
Figures 3 and 4 provide an overview of conservation areas relative to the Great
Plains (see Gauthier and Wiken, 1998 for a detailed analysis of that data).
4. Prairie Ecozone of Canada
One subdivision of the North American Great Plains is Canada’s Prairie Ecozone
(Wiken et al., 1997) that is further subdivided into 7 ecological regions (Figure 5).
Three ecoregions are restricted to a single province (the Fescue Grassland in Alberta; the Lake Manitoba Plain and Southwest Manitoba Uplands in Manitoba).
The Cypress Upland and the Mixed and Moist Mixed Grasslands occur only in
Alberta and Saskatchewan. Only the Aspen Parkland is contiguous throughout the
three Prairie Provinces. Saskatchewan contains the largest percentage of Canada’s
Prairie Ecozone.
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Figure 3. Protected areas of the Great Plains of North America (Source: Gauthier and Wiken, 1998).
MONITORING PRAIRIE HABITATS, CANADA
347
Figure 4. Protected areas >1,000 ha, Great Plains of North America (Source: summarized from the
North American Conservation Areas Database (NCAD), http://geogratis.cgdi.gc.ca/frames.html).
Figure 5. Prairie ecozone and ecoregions of Canada with distribution of grasslands (Sources: Environment Canada, Prairie Farm Rehabilitation Administration, Information Services Corporation of
Saskatchewan).
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Some grasslands of a much smaller size also occur in Canada. The drier southern valleys of British Columbia, parts of southern Ontario and Canada’s northern
latitudes are also examples of where grasslands exist.
5. Grassland Habitat within the Prairie Ecozone
Figure 5 shows the distribution of grasslands2 across the Prairie Ecozone. By some
accounts only 25–30% of the prairie ecozone of Canada now consists of rangeland
or grazing lands (Hammermeister et al., 2001). The largest remaining contiguous patches occur in Alberta and southwestern Saskatchewan. Figure 6 shows
the percentage of each ecoregion in grassland cover according to province. While
Saskatchewan has the greatest percentage of the Prairie Ecozone, Alberta3 has the
greatest percentage (43%) of grassland remaining, almost equal to that of Saskatchewan and Manitoba combined. Much of the remaining grassland occurs in the
Mixed and Moist Mixed Grassland ecoregions and the Aspen Parkland.
Native grasslands are part of Canadian heritage, although it is rare now to find
unbroken native grasslands large enough to show no evidence of European settlement (Hammermeister et al., 2001). Our beliefs, habits, arts and lifestyle are
strongly influenced by the environment we live in. Living on native grasslands
influenced the culture of First Nations and Métis people. Native plants and animals
were used for food, medicine, ceremonies, art, tools and weapons. For European
settlers, the native grasslands provided fertile soil and offered a means of providing
shelter (e.g., sod houses), a source of food and the foundation for an agricultural
lifestyle. The ranching lifestyle is intimately connected with the open rangeland
found only on the prairie. The grasslands serve as a source of food, medicine,
recreation, genetic resource, habitat for wildlife and as a benchmark of our past
environment.
6. Conservation Areas within the Prairie Ecozone
6.1. C ANADIAN CONSERVATION AREAS DATABASE (CCAD)
Information about conservation areas is integral to overall land use planning. The
conditions that prevailed before the dominance of human activities and land uses
(circa 1880 on the Canadian prairies) are typically used as measures against which
sustainability can be assessed. CCAD was developed by the Canadian Council on
Ecological Areas (CCEA) and its partners to provide a comprehensive view of the
types, location and general properties of conservation areas throughout Canada and
over time (Vanderkam and Wiken, 2001; Beric, 1999). CCAD is currently housed
on the GeoGratis (http://www.geogratis.ca/frames.html) site of Natural Resources
Canada.
MONITORING PRAIRIE HABITATS, CANADA
349
Figure 6. Percentage of prairie ecoregions in grassland cover according to province (Source: Gauthier
et al., 2002).
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DAVID A. GAUTHIER AND ED B. WIKEN
Figure 7. Conservation areas in Canada (Source: Canadian Conservation Areas Database, Natural Resources Canada, Canadian Council on Ecological Areas and GeoGratis,
http://geogratis.cgdi.gc.ca/ccea/).
CCAD embraces many conservation area interests from those agencies that seek
to protect regionally representative ecosystem types through to those that want to
manage important sites for other purposes (i.e., wildlife habitats, forest reserves)
but in an ecological manner. As such, assessments of conservation areas as well
as other nation and continental wide evaluations have traditionally relied on strong
connections to the national terrestrial and marine ecosystem framework of Canada
(Wiken and Gauthier, 1999).
6.2. A LBERTA
Alberta contains 33% of the Prairie Ecozone and approximately 1.1% (1,786 km2 )
of that land is managed for conservation purposes (Figure 8a). Grasslands occupy
43% (67,593 km2 ) of Alberta’s Prairie Ecozone. The Mixed Grassland and Aspen
Parkland ecoregions account for 69% of remaining grasslands in Alberta’s Prairie
Ecozone. Approximately 2% (1,115 km2 ) of remaining grasslands are within conservation areas.
MONITORING PRAIRIE HABITATS, CANADA
351
Figure 8. Grasslands and conservation areas, Prairie ecozone of Alberta and Manitoba, Canada
(Sources: Alberta Natural Heritage Information Centre, Manitoba Natural Resources, Environment
Canada).
6.3. M ANITOBA
Figure 8b shows the distribution and percent occurrence of remaining grassland in
Manitoba’s portion of the Prairie Ecozone overlaid with conservation areas for that
zone. Grasslands occupy 14,693 km2 (21%) of Manitoba’s Prairie Ecozone. The
Aspen Parkland and Lake Manitoba Plains contain 88% of remaining grassland in
Manitoba’s Prairie Ecozone. Approximately 1% (804 km2 ) of the Ecozone is under
some form of conservation management. Grassland makes up 21% (167 km2 ) of
conservation areas within Manitoba’s Prairie Ecozone.
6.4. S ASKATCHEWAN
Figure 9 shows the extent of grassland in the Prairie Ecozone of Saskatchewan by
ecoregion. Of all grasslands (58,859 km2 ) in the ecozone, native grasslands total
51,628 km2 or 21% of the Saskatchewan Prairie Ecozone (Hammermeister et al.,
2001). Figure 9 also shows areas managed for conservation purposes which total
22,277 km2 or approximately 9% of the Saskatchewan Prairie Ecozone. Native
grasslands account for 16,373 km2 (28%) of land cover within conservation areas
within the Saskatchewan Prairie Ecozone. Grassland habitat consists of small, frag-
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DAVID A. GAUTHIER AND ED B. WIKEN
Figure 9. Grasslands and conservation areas, Prairie ecozone of Saskatchewan, Canada (Sources:
Canadian Plains Research Center, Environment Canada, Prairie Farm Rehabilitation Administration, Saskatchewan Conservation Data Centre, Saskatchewan Environment, Saskatchewan Research
Council, Information Services Corporation of Saskatchewan).
mented patches throughout the zone, except for larger contiguous patches in the
southwest.
7. Mixed Grassland Ecoregion, Saskatchewan
The remainder of this paper focuses on one of the Saskatchewan ecoregions, the
Mixed Grassland. This ecoregion accounts for 36% of the Saskatchewan Prairie
Ecozone. Figure 10 displays the occurrence of native dominant grassland relative
to the extent of conservation areas in that ecoregion. Native grasslands account for
27,037 km2 (31%) of the ecoregion. Conservation areas account for 13,434 km2
of the ecoregion and contain 11,444 km2 (42%) of the native dominant grassland
within the ecoregion, i.e. 58% is not under a specific conservation management
program. Table II provides a summary of the extent of each conservation area
type in the ecoregion and the amount of native dominant grassland that each type
240,981 km2
(51.5%)
58,859 km2
(24.4%)
22,277 km2
(9.2% of Saskatchewan
Prairie Ecozone)
16,373 km2
(28% of total grassland
in Saskatchewan Prairie
Ecozone)
156,894 km2
(33.5%)
67,593 km2
(43.1%)
1,786 km2
(1.1% of Alberta Prairie
Ecozone)
1,115 km2
(1.6% of total grassland
In Alberta Prairie
Ecozone)
70,008 km2
(15%)
14,693 km2
(21%)
804 km2
(1.1% of Manitoba
Prairie Ecozone)
637 km2
(21% of total grassland in Manitoba Prairie
Ecozone)
Manitoba
Sources of data: Alberta Natural Heritage Information Centre, Canadian Plains Research Center, Environment Canada, Manitoba Natural Resources, Prairie Farm Rehabilitation Administration, Saskatchewan Conservation Data Centre, Saskatchewan
Environment, Information Services Corporation of Saskatchewan, Saskatchewan Research Council.
Area of grassland within conservation areas
Total area of conservation lands
Total area of grasslands
Total area prairie ecozone
Saskatchewan
Alberta
TABLE I
Grasslands and conservation areas within provinces, Prairie Ecozone of Canada
MONITORING PRAIRIE HABITATS, CANADA
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DAVID A. GAUTHIER AND ED B. WIKEN
Figure 10. Grasslands and conservation areas in the mixed grassland ecoregion, Saskatchewan,
Canada (Sources: Environment Canada, Prairie Farm Rehabilitation Administration, Saskatchewan
Research Council, Information Services Corporation of Saskatchewan).
contains. Wildlife Habitat Protection Act Lands and Prairie Farm Rehabilitation
Administration (PFRA) Community Pastures conserve the greatest amount of land
within the ecoregion as well as the greatest amounts of native dominant grassland.
Archibold and Wilson (1980) analyzed Dominion Land Survey township and
range maps. Those records indicate that over 90% of the Mixed Grassland Ecoregion circa 1880 was grassland (Figure 11). Figure 12 shows the decrease in
grassland that occurred in the ecoregion and increases in farm area and improved
land. By approximately 1930, much of the loss of native grasslands had occurred
with gradual declines occurring to the present.
8. Old Man on His Back Plateau Ecodistrict
Prairie habitat can be further monitored at a more detailed scale. Figure 13 shows
land cover for the Old Man on His Back Plateau ecodistrict in southwestern Saskatchewan. A high percentage (67%) of this ecodistrict is native dominant grassland
while about 30% is cropland.
Figure 13 also shows the extent of conservation areas for the ecodistrict. The
majority are provincially conserved lands, particularly Wildlife Habitat Protection Lands (42%) and Provincial Community Pastures (36%). There is a signific-
MONITORING PRAIRIE HABITATS, CANADA
355
Figure 11. Historic distribution of grasslands, mixed grassland ecoregion, Saskatchewan, Canada
(Source: Radenbaugh, in progress).
Figure 12. Historic decrease in grassland, mixed grassland ecoregion, Saskatchewan, Canada
(Sources: Archibold and Wilson, 1980; Canadian Agricultural Censuses 1931, 1991).
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DAVID A. GAUTHIER AND ED B. WIKEN
TABLE II
Extent of conservation areas and native dominant grassland in the mixed grassland ecoregion,
Saskatchewan, Canada
Conservation area types
Conservation areas
Native grasslands
area km2 % of ecoregion area km2 % of CA % of ecoregion
Migratory bird sanctuary
National park
National wildlife area
Prairie farm rehabilitation administration community pasture
Provincial historic site
Protected area
Provincial community pasture
Provincial heritage property
Provincial natural park
Provincial recreation park
Provincial historic park
Recreation site
Wildlife development fund land∗∗
Wildlife habitat protection act∗∗
Wildlife refuge
Nature conservancy of Canada
343
0.4%
914
1.1%
21 <0.1%
3915
4.5%
<1
44
1457
<1
74
5
<1
<1
12
6846
1
55
13687∗
<0.1%
0.1%
1.7%
<0.1%
0.1%
<0.1%
<0.1%
<0.1%
<0.1%
7.9%
<0.1%
0.1%
7
748
14
3553
2.1%
81.8%
66.7%
90.8%
<0.1%
2.8%
0.1%
13.1%
<1 100.0%
28 64.3%
1303 89.4%
<1 100.0%
55 74.3%
2 41.1%
<1 50.4%
<1 79.3%
7 56.2%
5898 86.2%
<1 34.8%
49 89.4%
11666∗
<0.1%
0.1%
4.8%
<0.1%
0.2%
<0.1%
<0.1%
<0.1%
<0.1%
21.8%
<0.1%
0.2%
43.1%
∗ Some areas are designated by more than one conservation area type. Thus, when summing across
conservation area types, cases of double counting may occur.
∗∗ For analysis and display purposes these conservation area types have been converted from quarter
section point centroids to polygons using the following criteria: (1) where quarter sections contain
150 or more acres of designated land, the complete quarter section is considered to be under conservation; and (2) where quarter sections contain fewer than 150 acres of designated land, buffers were
created around the quarter section centroids using the radius related to the acre value to determine
the area under conservation.
Sources of data: Canadian Plains Research Center, Nature Conservancy of Canada, Parks Canada,
Saskatchewan Conservation Data Centre, Saskatchewan Environment.
ant presence (19%) of some environmental non-government organization (ENGO)
lands held by Nature Conservancy of Canada. As well, PFRA has a small presence
(3%). Forty-nine percent of the ecodistrict is under some form of management
intended to serve conservation objectives. Of the 924 km2 of native grasslands,
conservation areas enclose about 65%.
Figure 14 shows the occurrence of land ownership for the ecoregion. Over twothirds of the ecodistrict is in private (privately owned or leased) hands, which means
that achieving conservation objectives is dependent upon partnerships with private
MONITORING PRAIRIE HABITATS, CANADA
357
Figure 13. Land cover and conservation areas for the Old Man on His Back Plateau ecodistrict,
southwestern Saskatchewan, Canada (Source: Gauthier et al., 2002).
landowners. The pattern of ownership relative to native grasslands is also shown in
Figure 14. This combined knowledge is essential in dealing with the securement of
additional land and in working with landowners in cooperative land management
for conservation purposes.
9. Assessing and Monitoring Habitat Fragmentation
Assuming that gaps exist in a conservation area system, which areas of remaining
habitat are of the highest priority to protect? Only assessing and monitoring indicators such as size and shape of habitats and their pattern of distribution will not
be sufficient. That is because the sensitivity and importance of landscape pattern is
scale-dependent, i.e. connectivity is not just a function of the spatial distribution of
habitats across a landscape, but also of the scale at which organisms interact with
landscape pattern (Forman and Godron, 1986; Turner, 1989).
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DAVID A. GAUTHIER AND ED B. WIKEN
Figure 14. Pattern of land ownership and native grassland, Old Man on His Back Plateau ecodistrict,
southwestern Saskatchewan, Canada (Source: Gauthier et al., 2002).
‘In fragmented landscapes, where islands of high-quality habitat are punctuated
by stretches of poor habitat, species that disperse over long distances will perceive
a given habitat distribution as more connected than will a species with short-range
dispersal. Thus, landscape pattern can act as a scale-dependent ‘filter’ acting differentially on the movement of species with different degrees of vagility, in much the
same way as high- and low-pass filters remove high and low frequency components
in a communication channel’ (Keitt et al., 1997, p. 1).
As a result, for organisms whose dispersal is affected by distance among patches,
those organisms can become isolated on individual habitat patches. Figure 15(a)
indicates that distances between patches that exceed the dispersal capacity of organisms effectively isolate those populations.
The removal of the largest patch in an area can potentially have the greatest
effect on connectivity. However, when weighted by area, the removal of a smaller
patch can also have a large (per area) contribution to connectivity. Such important
MONITORING PRAIRIE HABITATS, CANADA
359
Figure 15. (a) Patch fragmentation, nearest-neighbour distances and dispersal capacity. (b) Patch
fragmentation and ‘stepping-stone’ patches (Source: Modified from Keitt et al., 1997).
smaller patches have been called ‘stepping-stone’ patches (Keitt et al., 1997). In
the hypothetical example shown in Figure 14, the loss of a stepping stone patch is
significant.
Therefore, it is insufficient for assessment and monitoring purposes to rely
solely on identifying remaining native grassland habitats and tracking what happens to all native grassland patches in an area over time relative to what is conserved and what is not. In fragmented landscapes, some patches may perform a
more significant ecological function as stepping-stones for certain species than others and they need to be identified and monitored. In Figure 15(b) the hypothetical
population within the cluster of small patches is in trouble. While members of the
population can disperse among the small patches, there are insufficient resources
to meet its requirement for a minimum viable population, and it lacks the dispersal
capability to move to a larger core area. From a conservation management perspective, should resources be allocated to protect those patches? Should degraded
land outside of those small patches be restored in order to create habitat to sustain
that population?
Following from the above discussion, spatial metrics were calculated using the
FRAGSTATS program (McGarigal and Marks, 1995) for grassland habitat within
the Old Man on His Back Plateau ecodistrict (Table III). In addition to some useful
area summary information, there are 104 patches of native grasslands in the ecodistrict with an average patch size of just under 9 km2 with a high coefficient of
variation value. There is a great deal of variation of patch size in this ecodistrict and
the largest single patch takes up 38% of the total area of native dominant grassland.
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DAVID A. GAUTHIER AND ED B. WIKEN
TABLE III
Spatial metrics for grassland habitats, Old Man on His Back Plateau ecodistrict,
southwestern Saskatchewan, Canada
Metric
Value
Landscape area
Area of native grassland (NG)
NG – Percent of landscape
Number of NG patches
NG patch density per 100 ha
Mean NG patch size
Largest patch index – NG
Area-weighted mean shape index – NG
Area-weighted mean patch fractal – NG
Mean nearest neighbour distance – NG
Number of core areas – NG
Total core area – NG
1,373 km2
924 km2
67%
104
0.1
888.5 ha (8.9 km2 ) (C.V.=678.9)
38% of NG lands
7
1.3
139.3 m (C.V.=168.9)
43
423 km2
The shape index values are interesting to note. If the area-weighted mean shape
index were equal or close to a value of 1, the patches would tend to a circular
shape. In this case, the patches of native grassland tend to a very irregular shape,
i.e. a higher perimeter to area relationship important for edge species. Another
measure of shape is the area-weighted mean patch fractal dimension. If that value
was equal or close to 1, the patches would be of relatively simple shape. The
further away from an index value of 1, the more convoluted the shape. Shape is an
important consideration from the point of view of biogeographic theory related to
conservation area planning and the SLOSS (‘single large or several small’) debate
(Shafer, 1990; Soulé and Simberloff, 1986).
The mean nearest neighbour distance metric is informative in regard to fragmentation and dispersal potential among patches. On average in this ecodistrict,
organisms will need to be able to disperse a distance of about 140 m before encountering another native grasslands patch. As in the case of patch size, there is a
high coefficient of variation associated with this metric.
Even if individuals have the capacity to disperse among patches, there may be
insufficient numbers of core areas to sustain viable populations. In this ecodistrict,
there are 43 core areas totalling 423 km2 . In ecological terms, ‘core areas’ refer to
the minimum habitat size and quality required to sustain a viable population of a
species (McGarigal and Marks, 1995). As an example, if we have data to conclude
that a minimum viable population of a species in this area requires a habitat patch
MONITORING PRAIRIE HABITATS, CANADA
361
of 25 ha (250,000 m2 or 1/4 km2 .), then the analysis indicates that there are 43 core
areas that meet that size requirement.
In the introduction to this paper, four questions were asked of relevance to
assessing and monitoring of grassland habitats on the prairies:
• How much native grasslands remains?
• Which areas of the Prairies are under some form of conservation management?
• How much of the native grasslands are currently conserved?
• What is the extent of fragmentation of native grassland habitats?
Based on the above discussion, the following can also be asked:
• Which are the most critical patches to secure to conserve native grassland habitats?
• Can any serve as core habitats and ecosystem types?
• What are the potentials for connectivity and dispersal among habitat patches at
various scales?
Changes in the values of patch metrics in a region at various scales should be
monitored as indicators of changes in critical habitats. Also, the fact that a patch
of habitat may not contain very many individuals of a species does not mean that
patch is unimportant in the survival of a population of that species – it could serve a
stepping-stone function in terms of a crucial link within a broader region. Where resource allocation decisions need to be made, managers may need to place priorities
on the protection of patches of habitat based at least in part on their importance as
connectivity links, and taking into consideration the habitat requirements of diverse
species with their respective vagility/dispersal ability, as discussed above.
10. Concluding Comments
Continued assessment and monitoring of the extent and distribution of grassland
habitats and characteristics of spatial patterning can provide important guidance to
decision-makers relative to meeting conservation objectives. Such initiatives are of
immediate and long-term importance. There is reason to be very concerned about
human impacts on wildlife habitats and their associated properties (i.e., vegetation
cover, wetlands) on the prairies of Canada. For example, endangered wildlife and
habitats that occur across much of the southern latitudes of Canada are the legacies
of land and water developments that have overly favoured resource exploitation and
production (Gauthier and Wiken, 2001). In addition, climate modeling scenarios
for the prairies show expansions in areas of increased aridity (Brklacich et al.,
1998). The implications of increased arid areas in terms of impacts on already
fragmented and disturbed prairie habitats need to be carefully considered. Not
every environmental impact can be mitigated, and planning for adaptations necessary to cope with anticipated changing habitats is an important need. To facilitate
such planning, detailed site-specific rigorous scientific investigations of habitat
conditions, wildlife abundance and distribution relative to remaining grasslands
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DAVID A. GAUTHIER AND ED B. WIKEN
are required. The use and interpretation of landscape metrics require sound biological and physical data and, for many species on the prairies, adequate population
and dispersal data are lacking. Key scale-dependent indicator species need to be
identified for each ecoregion and their habitat requirements and dispersal capabilities. Assessment and monitoring programs also need to incorporate quantitative
and qualitative evaluations of habitat conditions, e.g. habitat amounts, patterns,
structures; indicators of habitat quality; spatial metrics; and absolute and relative
rates of change.
Concerns about native grassland habitats and ecosystems extend beyond just
conservation areas. The care and management of surrounding areas require similar
types of data and analysis to ensure that the landscape as a whole is managed
sustainably. However, in the prairies, where human activities and land uses have
eliminated many of the natural ecosystem benchmarks, there are few places that
can act as basic reference points against which to measure and judge sustainable
resource use activities. Owing to the scarcity and fragmentation of remaining natural areas in the Prairie Ecozone of Canada, conservation areas are critical sentinels
playing very strategic roles in ecosystem based monitoring and research networks.
Notes
1. Modifications to conservation area networks are occurring in all jurisdictions on an on-going
basis presenting a continuing challenge for the updating of electronic databases. The NCAD
database discussed in this chapter will require periodic updating. For example, parks for Alaska
are not yet included in the database. Also, changes are on-going with the Mexican system
of protected areas, for example, in February 2002 the 15,000 ha El Tokio protected area was
established in the Mexican grasslands.
2. Grasslands generally include land that is in perennial grasses and herbaceous species for grazing
or other uses including native range, seeded tame pasture, abandoned farm areas and other noncultivated uses (e.g. ditches, riparian areas etc.). Grasslands represent an environment historically
or currently dominated by graminoids, occurring primarily over light to dark brown chernozemic
soils, under semi-arid to arid conditions with dry, warm summers. In the Canadian prairies, grasslands are also characterized by relatively low relief landscapes with upland vegetation dominated
by perennial grasses as a result of natural drought, grazing and/or fire regimes (CEC, 1997;
Rzedowski, 1988; World Resources, 2001). They can be considered transitional ecosystems,
which with more moisture would become forested, or with less would turn to desert. (Henwood,
1998).
3. Alberta has done an excellent job in mapping its native grasslands areas, linking that information
to land ownership (56% (2,328,715 ha) of Alberta’s remaining grasslands are under Crown
ownership). Information on Alberta’s protected areas can be found at http://www.cd.gov.ab.ca/
preserving/parks
MONITORING PRAIRIE HABITATS, CANADA
363
Acknowledgements
For their assistance in helping to draw together much of the data used in this paper,
thanks go to Lorena Patino and Katherine McGovern of the Canadian Plains Research Center, and Robert Vanderkam of GeoAccess Division, Natural Resources
Canada. In addition, we want to express our gratitude to: the Prairie Farm Rehabilitation Administration for their permission to use land cover data for the Prairie
Ecozone of Canada; to Saskatchewan Environment and Resource Management and
Saskatchewan’s Conservation Data Centre for their cooperation in the development
of the conservation area database for Saskatchewan; to Manitoba Parks and Natural
Areas for conservation area data for Manitoba; and to the Alberta Natural Heritage
Information Centre for conservation area data for Alberta.
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