Woodland caribou scientific review to identify critical habitat: chapter 10
6.3 Literature Review of Boreal Caribou (Ranfiger tarandus caribou) Habitat Use in Ecozones across their Distribution in Canada
Woodland caribou (Rangifer tarandus caribou) are distributed in the boreal forest across nine ecozones in Canada. Several ecotypes of woodland caribou have been classifi ed, including boreal, forest tundra, northern mountain and southern mountain, based on their adaptation to various environments (Thomas and Gray 2002). In 2002, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) listed the boreal caribou ecotype as threatened (Thomas and Gray 2002). The boreal caribou is a forest-dwelling sedentary ecotype of woodland caribou. The range of the listed boreal caribou extends throughout the boreal forest in nine provinces and territories, from southwest Northwest Territories to Labrador (Figure 1).
Habitat encompasses the broad suite of biotic and abiotic resources and conditions that govern the survival, reproduction, and presence of a species (Caughley and Gunn 1996). The limiting factors assembled for caribou populations include predation (Bergerud 1974, 1980, Bergerud and Elliot 1986, Seip 1991, Stuart-Smith et al. 1997, Rettie and Messier 1998, Whittmer et al. 2005), meteorological conditions (Brown and Theberge 1990), food availability (Schaefer 1988), insect harassment (Downes et al. 1986; Walsh et al. 1992), and harvesting by humans (Bergerud 1967; Edmonds 1988).
The key to understanding habitat is scale. Individual animals select habitat at multiple scales to meet their life history requirements and avoid hazards. Johnson (1980) proposed a hierarchy of habitat selection, including species range scale, home range scale, within range (seasonal) habitats, and fi ner scales of resource selection, driven by efforts to minimize effects of limiting factors.
Rettie and Messier (2000) hypothesized that, across spatial scales, population-limiting factors can be linked to habitat selection. This argument has two components: First, habitat selection may occur simultaneously on multiple scales, often framed as a nested hierarchy. For instance, animals may select a home range, feeding sites within the home range, and dietary items within a site (Senft et al. 1987). Second, selection at each of these scales represents a ranking of limiting factors. Animals are hypothesized to select resources (or perhaps avoid some condition) in an attempt to overcome the chief limitation at each scale; if unable to do so, they continue to select that resource at successively fi ner scales. The scales of habitat selection can thus reveal an ordered list of limiting factors. The broadest scales are most pertinent to survival and reproduction (Rettie and Messier 2000).
There is wide agreement that the primary proximate limiting factor for boreal caribou populations is predation, driven by natural or human-induced landscape changes that favour early seral
stages and higher densities of alternative prey (Bergerud and Elliott 1986, Bergerud 1988, Ferguson et al. 1988, Seip 1992, Cumming et al. 1996, Stuart-Smith et al. 1997, Rettie and Messier 1998, Schaefer et al. 1999, Courtois 2003, Courtois et al. 2007, Vors et al. 2007). The distribution of woodland caribou appears to occur in refugia, often away from high densities of predators and their alternate prey (Bergerud et al. 1984, Bergerud 1985, Cumming et al. 1996, Rettie 1998, James 1999, Racey and Armstrong 2000). If caribou can fi nd such refugia, then snow appears to act as a factor at slightly fi ner scales, such as foraging areas with softer and shallower snow cover (Stardom 1975, Brown and Theberge 1990). Finally, selection for lichens occurs at even fi ner scales such as feeding craters chosen for their high lichen content (Schaefer and Pruitt 1991) or graminoids and equisetum.
The scale of habitat selection should refl ect the relative importance of limiting factors, whereby a limiting factor should drive selective behaviour at increasingly fi ner scales until the next most dominant limiting factor supersedes selection (Rettie and Messier 2000). Bergerud et al. (1984) hypothesized that minimizing exposure to predation is the strongest driver of coarsescale caribou habitat selection. For example, at a broad scale, boreal caribou select mature conifer forests and peatland complexes, both of which support few predators or alternative prey. During calving season, cows typically select treed islands surrounded by open water in peatlands or lakes to further reduce risk of predation. The open water is hypothesized to facilitate escape from predators. Although some of these islands may support sub-optimal forage quality and quantity, the inference is that the risk of predation exceeds the need for high quality forage and that predation still remains the chief limiting factor within a home range.
At fi ne spatial scales, food availability and microclimate factors are considered important drivers of caribou habitat selection (Rettie and Messier 2000). During spring, female caribou feed on nutrients important for lactation (equisetum and graminoids), and during winter the exploit protein-rich sedges (Carex spp.) and equisetum and terrestrial and in some areas arboreal lichens (e.g., Bryoria spp. and Alectoria sarmentosa; Helle 1980, in Rettie and Messier 2000). During summer, when biting insects are abundant, boreal caribou have been reported to use sparsely treed ridgelines near lakeshores, purportedly to reduce insect harassment (Shoesmith and Storey 1977, Hillis et al. 1998).
Although boreal caribou are considered non-migratory, movements made between seasonal ranges (particularly pre-calving and pre-rutting) vary considerably, from almost no betweenseason movements in Alberta, central Saskatchewan, and southeastern Manitoba (Fuller and Keith 1981, Darby and Pruitt 1984, Bergerud 1985, Edmonds 1988, Stuart-Smith et al. 1997, Rettie and Messier 2000), to more than 20 km in northwestern Ontario (Ferguson and Elkie 2004a) or 40.5 km mean distance (range 12 - 119 km) in northeastern BC (Culling et al. 2006) and 75 km in Labrador (range 10 - 520 km; Brown et al 1986). Boreal caribou in Manitoba have been recorded moving distances of greater than 200 km (V. Crichton pers. comm.). Connectivity between seasonal habitats fulfi lls a potentially critical function in reducing risk of predation for boreal caribou during times of increased movement. Caribou migrating to and from their wintering areas used coniferous forests (Ferguson and Elkie 2004a, Darby and Pruitt 1984, Lefort et al. 2006). In northwestern Ontario, caribou were more likely to avoid open water, disturbed and open areas while using coniferous forests during migration to and from wintering areas (Ferguson and Elkie 2004a).
Habitat conditions over their entire range impact the viability of boreal caribou populations. The major threat to boreal caribou is increased predation that appears to be related to habitat changes that increase the number and distribution of alternative prey species and their associated predators in caribou habitat. Consequently, although special management practices may be required to protect seasonal foraging habitats, calving habitats, and migration connectivity, it is also important to manage the surrounding habitats to reduce the risk of predation, even if the caribou rarely or never "use" those habitats. Caribou do not respond to the landscape at human-centred scales; their "use" of habitats appears to extend for kilometres (Mayor et al. 2007), well beyond the bounds of conventional human perceptions. The importance of managing the matrix habitat surrounding the core habitat to reduce predation risk is recognized for the mountain ecotype of boreal caribou, which face similar issues of increased predation risk where the number and distribution of early seral ungulates has changed following habitat change (Government of British Columbia 2005).
The purpose of this report is to summarize boreal caribou habitat use from studies published in primary literature as well as government and non-government reports.
The description of habitat use is organized by Ecozone (Figure 1), the most generalized classifi cation of the Canadian ecological unit hierarchy framework (ESWG 1995). The largest Ecozone, the Boreal Shield, is further divided into fi ve forest regions adapted from Rowe (1972). Habitat use is reported for populations existing outside of the boreal caribou range (e.g. southern mountain or Newfoundland) if the results were thought to be informative for defi ning boreal caribou Critical Habitat. For each Ecozone, broad-scale caribou habitat is described, followed by, fi ner scale habitat for each season (calving, post calving, rutting, winter [early and late]) as well as for the travel period between seasons.
Consistent common names of plant species and habitat type were used where possible. In some cases, variations in common names occurred among Ecozones (e.g. bog, string bog, basin bog, peatland complex, treed muskeg, treed wetland, etc.).
Appendix 6.3 - Figure1. Boreal caribou distribution within nine Ecozones in Canada.
TAIGA SHIELD ECOZONE
Coppermine River Upland, Tazin Lake Upland, Selwyn Lake Upland, La Grande Hills, Southern Ungava Peninsula, New Quebec Central Plateau, Ungava Bay Basin, Kingarutuk-Fraser River, Smallwood Reservoir-Michikamau, Coastal Barrens, Winokapau Lake North, Goose River West, Mecatina River, Eagle Plateau, Harp Lake, Nipishish Lake (68, 69, 71, 72, 73, 74, 75, 77 (81), 78, 79, 80 (83, 86), 82, 84, 85)
The Taiga Shield Ecozone occurs east of Hudson Bay, in northern Quebec and southern Labrador (Figure 2) and is comprised of the Taiga Forest and the Canadian Shield on broadly rolling terrain (ESWG 1995). The landscape is dominated by bedrock erratics, eskers, and hummocky and ridged morainal deposits. Many lakes, peatlands, and open forests with intervening shrublands and meadows exist in this Ecozone. Black spruce (Picea mariana)is the dominant tree species in the Ecozone, although open mixedwood stands of white spruce (Picea glauca), balsam fi r (Abies balsamea), trembling aspen (Populus tremuloides),balsam poplar (Populus balsamifera), and white birch (Betula papyrifera) dominate the southern portion of the Ecozone and open arctic tundra dominates the northern portion of the Ecozone. Open black spruce and jack pine (Pinus banksiana) forests dominate the centre of the Ecozone, and lichen (Cladonia and Cladina) are the primary understory species. Lichen woodlands generally occur in nutrient poor sandy soils of glacial deposits. Upland areas are well drained and prone to fi re. White birch and tamarack (Larix laricina) are considered the dominant pioneer species post fi re, and are eventually replaced by black spruce. Throughout the southern and central portion of the Ecozone, higher elevations are dominated by open arctic tundra and low shrubs. Precipitation ranges from 500 mm to over 1,000 mm per year. Mean annual area burned by forest fi re is 0.14% (NRCAN 2002).
Local Caribou Populations
Six local boreal caribou populations occurring within the Taiga Shield are described in the literature. The extent of occurrence of some of these local populations overlaps with the Boreal Shield Ecozone. The following local populations are listed in the habitat use literature:
QC: Magpie, Caniapiscau, and Lac Bienville. Labrador: Lac Joseph, McPhadyen River, Red Wine Mountains, Mealy Mountains. The McPhadyen River population was associated with the Lac Joseph population but no longer exists. The Red Wine Mountains population was associated with two local populations that no longer occur: Dominion Lake and St. Augustin. Lac Joseph and Magpie are the same population, sharing a border between Quebec and Labrador
Broad-Scale Caribou Habitat
Caribou habitat in the Taiga Shield is described as upland tundra consisting of rounded, barren hills dominated by ericaceous shrubs (Ericaceae spp.), lichens, grasses (graminoids) and sedges and lowlands consisting of numerous peat bogs (muskegs and string bogs), lakes,
Appendix 6.3 - Figure 2. Boreal caribou distribution within the Taiga Shield Ecozone. rivers, and riparian valleys. Forest-wetland habitat and closed conifer forests are extensive (Brown et al. 1986). Courtois et al. (2004) described caribou habitat as dense mature conifer and open conifer with abundant lichens. Coastal areas and off-shore islands are available to caribou in the eastern portion of the Taiga Shield (Schmelzer 2004).
Seasonal Habitat and Forage
Bergerud (1963, in Schmelzer et al. 2004) described traditional calving areas as string bogs and large muskegs. The use of peninsulas or islands varies by the amount of open water in the range. Females tend to calve on islands more frequently in the Caniapiscau and Lac Bienville populations, where there is more open water.
Fidelity to calving sites seems to vary among individual caribou; some caribou return to the same site in consecutive years, some have calving locations separated by several hundred kilometres in subsequent years, and many return to a general area within their range. General calving site fi delity was recorded by Brown et al. (1986; ~87% of 103 radio-collared caribou in three populations selected a calving site within 10 km of the previous year's calving site and 33% calved within 3 km of previous year's site) and Hearn and Luttich (1987; within 15 km of the previous year's calving site, in Schmelzer et al. 2004).
Some females traveled several hundred kilometres to these general calving areas. Brown et al. (1986) recorded female caribou in the Caniapiscau population traveling between 200 and 500 km to their calving areas each year. Calving areas represent a small portion of the range; Brown and Theberge (1985) reported that cumulative area of all calving locations represented less than 3% of the available range.
Caribou disperse widely across the range during calving period and densities were estimated at below 0.03 caribou per km2 (Brown et al. 1986). Calving sites selected by caribou from the Red Wine Mountains population were located in treed bogs (Brown and Theberge 1985) or small open wetlands (<1 km2) and typically one female per wetland was observed (Brown et al. 1986). Many calving sites were located in islands or peninsulas (Brown et al. 1986).
Caribou were relatively sedentary throughout the summer and remained in forested wetland (Brown et al. 1986). Fidelity by adult females can be most pronounced at this time of year. Females in the Red Wine Mountains herd returned, on average, to within 6.7 km of the previous year's site (Schaefer et al. 2000).
Caribou moved greater distances during the rutting season and formed larger rutting groups. Caribou were observed in open wetlands during the rutting season (Brown et al. 1986).
Bergerud (1994, cited in Schmelzer et al. 2004) described winter range as uplands and sand fl ats in proximity to rivers. During winter, Lac Joseph caribou used forested wetland more than upland tundra (Brown et al. 1986; Saint-Martin and Theberge 1986, in Schmelzer et al. 2004). The extreme snow depths in the Taiga Ecozone limit the ability of caribou to access terrestrial lichen. Brown and Theberge (1990) found that cratering activity in the Red Wine Mountains population did not occur in snow depths above 125 cm and ram-hardness values of approximately 500 kg. During deep snow conditions, caribou seek bedrock erratics, where snow sheds easily (I. Schmelzer pers. comm.). Caribou form small groups and selected lakes for loafi ng and rumination in winter, where a clear view of predators is maintained (I. Schmelzer pers. comm.). In snow conditions below the threshold, caribou formed groups and cooperatively dug craters to access food (Brown and Theberge 1990). During winter, caribou in the Red Wine Mountains of Labrador selected bog edges as well as glacial erratics, where terrestrial lichens were abundant (Brown and Theberge 1990). In the 1980s, some of the Red Wine Mountains population wintered in mature white spruce and fi r stands that provided an important alternate food source in the form of arboreal lichens (Brown 1986). Folinsbee (1975, 1978; reported in Schmelzer 2004) found used areas in winter had signifi cantly lower snow depths than non-used areas, and snow under forest canopy was softer and shallower than snow outside of forests. In deep snow years, Mealy Mountains caribou formed groups and traveled to the alpine, windswept Mealy Mountains or in bogs along lake or ocean shore (Bergerud 1967, Hearn and Luttich 1987). During winters with low snowfall, caribou did not congregate in groups and used heavily forested areas (Bergerud 1967).
Late Winter Habitat
Caribou whose range includes mountainous habitat moved to the tundra habitat of the mountains in late winter, possibly to avoid deep snow conditions at lower elevations (Brown et al. 1986, Brown and Theberge 1990). Movements from the forest wetland habitat to upland tundra ranged from 16 - 86 km.
Travel Season Habitat
Prior to calving, caribou dispersed widely from late winter aggregations and the greatest movements of radio-collared females between successive relocations occurred during the travel season prior to calving (Brown et al. 1986). The greatest daily movement rates occurred prior to calving (up to 38 km) and during fall after the rutting season (up to 51 km, I. Schmelzer pers. comm.).
HUDSON PLAINS ECOZONE
Hudson Bay Lowland, James Bay Lowland (216, 217)
The Hudson Plains Ecozone encompasses portions of northern Ontario, western Québec and northeastern Manitoba (Figure 3) and is a low elevation plain referred to as the James Bay Lowlands. The region is a transition zone between coniferous forests to the south and tundra to the north. Poorly drained areas supporting bogs and fens are extensive and interspersed with black spruce covered ridges or tamarack stands. Sedges, mosses and lichens dominate the ground cover. Mean annual precipitation ranges from 400 mm in the northwest to 800 mm in the southeast (ESWG 1995). Mean annual area burned by forest fi re is 0.09% (NRCAN 2002).
Local Caribou Populations
Three local boreal caribou populations occurring within the Hudson Plains Ecozone are described in the literature in addition to the continuous distribution of boreal caribou throughout the Ecozone. The extent of occurrence of some of these local populations overlaps with the Boreal Shield Ecozone. The following local populations are listed in the habitat use literature: La Sarre, Rupert, and Michipicoton.
Broad Scale Caribou Habitat
The most suitable caribou habitat in this region includes all ages of shrub-rich treed muskeg and mature conifer (Brown 2005). Magoun et al. (2005) described caribou habitat as poorlydrained landscapes dominated by sedges, mosses and lichens with scattered, open stands of black spruce and tamarack. The home ranges of caribou in this region were larger than those reported in the literature for other regions of Canada (Brown et al. 2003).
Seasonal Habitat and Forage
Caribou in the Hudson Bay lowlands avoided tamarack fens year round (Magoun et al. 2005). Courtois (2003) determined that at the home range scale, caribou preferred habitats susceptible to reduce predation risk by selecting mature conifers, water bodies, areas with lichens and wetlands and avoiding perturbed habitats. Forest fragmentation, however, constrained the pattern of habitat selection by caribou. Individuals living in highly fragmented landscapes did not select against perturbed habitats, presumably because they could not fi nd enough suitable habitats in such landscapes or because they gave priority to dispersion as an anti-predator strategy. Core activity areas for winter and summer occurred did not overlap in this region and (Brown et al. 2003).
Appendix 6.3 - Figure 3. Boreal caribou distribution within the Hudson Plains Ecozone.
During calving, caribou preferred mature conifer stands without lichens, conifer stands with lichens and wetlands (Courtois 2003). Caribou were found more frequently at higher altitudes during calving than during other periods.
In the northeastern recovery zone of Ontario, caribou were associated with fens, bogs, and lakes during summer (Pearce and Eccles 2004).
During the rut, caribou preferred conifer stands with lichens and wetlands, followed by mature conifer and conifer in regeneration (Courtois 2003).
In winter, caribou preferred dense conifer (Pearce and Eccles 2004), wetlands and mature conifer with lichens (Courtois 2003). Caribou selected areas where terrestrial lichens were abundant on ombrotrophic peat deposits (Brokx 1965). Lichen woodlands and lichen heaths were avoided. Most caribou wintered in raised bogs, especially in peatland complexes with abundant patches of bog (Brokx 1965).
Late Winter Habitat
In late winter, caribou used large patches of intermediate aged and mature black spruce, shrub rich treed muskeg, and mixed conifer and avoided forests with abundant deciduous species (Brown et al. 2007). In late winter, caribou selected areas with abundant mature black spruce and where contiguous patches of preferred habitat were larger. Caribou avoided forests with an abundance of deciduous trees (Brown et al. 2007).
Travel Season Habitat
In the James Bay Lowlands, home range size of caribou was positively correlated with moose (Alces alces) density during periods of long-range movements, and negatively correlated with moose density during sedentary periods, suggesting avoidance of moose to reduce risk of predation during most of the year (Brown 2005). Movements were greater during fall and late winter when caribou were travelling to and from summer and early winter ranges (Brown et al. 2003).
BOREAL SHIELD ECOZONE
The Boreal Shield Ecozone is vast, extending from northern Saskatchewan to Newfoundland, north of Lake Winnipeg, the Great Lakes, and the St. Lawrence River (ESWG 1995; Figure 4). The landscape is rolling, with abundant uplands and wetlands. Peatlands dominate the wetlands throughout central Manitoba, northwestern Ontario, and Labrador. Small to medium-sized lakes occur throughout the Ecozone. The dominant vegetation is coniferous trees in the northern reaches of the Ecozone, with greater abundance of mixed conifer and deciduous trees in the southern extent. Exposed bedrock outcrops and their associated lichen dominate the landscape. Shrubs and forbs occur and dominate non-forested areas. Mean annual precipitation ranges from 400 mm to 1600 mm (ESWG 1995). Mean annual area burned by forest fi re is 0.36% (NRCAN 2002).
Due to the vastness of the Boreal Shield and the variation in climate, topography and types of vegetation, the habitat descriptions for boreal caribou in this Ecozone have been delineated
to 5 sub regions:
1) Boreal Shield East (Labrador/NE Québec): Rivere Rupert Plateau, Central Laurentians, Mecantina Plateau, Paradise River, Lake Melville Ecoregions (100, 101, 103, 104, 105)
2) Boreal Shield Southeast (Southern Québec): Abitibi Plains, Southern Laurentians Ecoregions (96, 99)
3) Boreal Shield Central (Western Québec, NE Ontario): Abitibi Plains, Lake Timiskaming Lowlands Ecoregions (96, 97)
4) Boreal Shield West Central (Lake Superior): Lac Seul Uplands, Lake Nipigon Ecoregions (90, 94)
5) Boreal Shield West (NW Ontario, Manitoba, Saskatchewan): Athabaska Plain, Churchill River Upland, Hayes River Upland, Big Trout Lake Ecoregions (87, 88, 89, 95)
BOREAL SHIELD EAST
Rivere Rupert Plateau, Central Laurentians, Mecantina Plateau, Paradise River, Lake Melville Ecoregions (100, 101, 103, 104, 105)
This region extends from west-central Québec east to the northeastern extent of Québec (Figure 4). Closed stands of black spruce and balsam fi r dominate the western extent of this sub region (ESWG 1995). Open stands of white spruce with lichen and white birch exist in well-drained sites. Closed stands of black spruce and balsam fi r dominate the low lands, while open stand of black spruce and white spruce, with their associated lichens and feather moss dominate the well drained sites. White birch and trembling aspen also occur in well drained sites. Eastern white cedar (Thuja occidentalis) and black spruce dominate the wetland areas. Closed, dense stands of black and white spruce and balsam fi r dominate the moist sites along riparian habitat. Bedrock outcrops are dominated by lichen. Bogs dominate
Appendix 6.3 - Figure 4. Boreal caribou distribution within the Boreal Shield Ecozone.
the lowlands and lower valleys and raised dome bogs occur in the eastern portion of the sub region. Krummholtz vegetation occurs on exposed hilltops. Mean annual precipitation ranges from 650 - 100 mm (ESWG 1995). Mean annual area burned by forest fire is 0.24% (NRCAN 2002).
Local Caribou Populations
The following local population names or local regions occur in the habitat use literature for this region: Lac Joseph/Magpie, Petite Lac Manicouagan (Manic), and Manouane-Manicouagan (Manou); Pipmuacan (Pipmu).
Broad Scale Caribou Habitat
Boreal caribou habitat in the northern part of their range in Québec includes continuous conifer-feather moss forests on poorly-drained sites and conifer uplands with nearly continuous terrestrial lichen ground cover (Cladina spp., Cladonia spp. and Cetraria spp.; Arseneault et al. 1997). Caribou preferred mature conifer with lichens, water bodies, and wetlands and avoided disturbed habitats (Courtois 2003).
Seasonal Habitat and Forage
Year Round Habitat
Caribou in the southern extent of this region avoided burns and clear-cuts, deciduous and mixed forests, and heath without lichens throughout the year (Courtois et al. 2007) as well as jack pine stands younger than 40 years (Crête et al. 2004).
Caribou from four populations in the Boreal Shield East selected open wetlands, peninsulas and islands for calving habitat (Brown et al. 1986). During spring, caribou in Newfoundland selected sedges, ericaceous species, bryophytes, alder (Alnus spp.) and larch (Bergerud 1972). In the western extent of the region, caribou selected balsam fi r, dense black spruce stands, mixed spruce-fi r forests older than 40 years, and dry bare land that supported high densities of lichens (Crête et al. 2004). During the calving season, caribou avoided recent burns or harvested stands, pine stands less than 40 years-old, and jack pine stands. In the southern extent of the region, cows preferred mature conifer stands with and without lichens, and wetlands during calving season (Courtois 2003). Caribou cows did not use islands or water bodies for calving, but were found at higher altitudes than during other periods.
During summer, caribou selected open and forested wetlands in northeastern Québec and continued to use islands and peninsulas (Brown et al. 1986). In Newfoundland, caribou selected aquatic plants, dwarf birch (Betula glandulosa), deciduous shrubs, ericaceous species, and moss (Bergerud 1972).
In the Boreal Shield East, caribou moved greater distances during the rutting season and formed larger rutting groups. Caribou were observed in open wetlands during the rutting season (Brown et al. 1986). In Newfoundland, caribou selected terrestrial and arboreal lichens, forbs, sedges, mosses, and coniferous and deciduous shrubs during fall (Bergerud 1972). In the southerly portion of the region, Rutting included balsam fi r stands, dense spruce, spruce-fi r forest older than 40 years, and dry bare land (Crête et al. 2004). Stands with abundant lichens and wetlands were preferred, followed by mature conifer and young seral stage conifer (Courtois 2003).
Caribou in this region avoided arboreal lichens, possibly because the lichen available was non-pendulous (Brown and Theberge 1990). Caribou from other Labrador/Northern Québec populations selected forested wetlands during winter (Brown et al. 1986). Some caribou used upland-tundra for loafi ng, but returned to lichen woodlands for feeding (Brown et al. 1986). In the southern extent of the region, caribou selected balsam fi r stands, dense spruce stands, mixed spruce-fi r older than 40 years, dry bare land (Crête et al. 2004), mature conifer, and wetlands. (Courtois 2003).
BOREAL SHIELD SOUTHEAST
Abitibi Plains, Southern Laurentians Ecoregions (96, 99)
This region encompasses two isolated boreal caribou populations, in southwestern Québec, and in the Laurentians of south-central Québec (Figure 4). The region is characterized by mixed forest of white spruce, balsam fi r, white birch and trembling aspen (ESWG 1995). In dry sites, jack pine forests or mixed forests of jack pine, white birch, and trembling aspen occur and on wet sites, black spruce and balsam fi r or tamarack stands occur. Forest understory is typically moss or lichen. Basin bogs are abundant in the northern portion of the sub region, and rock outcroppings occur more frequently in the southern extent. The eastern extent of the region is more undulating. Annual precipitation ranges from 725 mm to 1000 mm (ESWG 1995). Mean annual area burned by forest fi re is 0.06% (NRCAN 2002).
Local Caribou Populations
This subregion contains only two isolated boreal caribou populations: Charlevoix and Vald'Or.
Broad Scale Caribou Habitat
Boreal caribou habitat in this region includes late seral-stage black spruce-dominated lowlands and jack pine-dominated uplands (Duchesne et al. 2000). Within the range of the Charlevoix population, south of the continuous boreal caribou distribution, open black spruce forests with dwarf birch and Ericaceae spp. dominate (Duchesne et al. 2000). An extensive lichen community, the basis of the population's winter diet, includes Cladina spp., Cladonia spp. and Cetraria spp. (Duchesne et al. 2000).
Seasonal Habitat and Forage
During spring, caribou selected open, medium-closed conifer forests (Lefort et al. 2006)
Pre Rutting and Rutting Habitat
During the pre-rutting period, caribou selected open and dense mature conifer forests, including spruce, tamarack, jack pine, as well as younger coniferous forests aged 30 - 50 years (Lefort et al. 2006). During the rutting and post-rutting period, caribou selected open mature and young coniferous forests.
In early winter through late winter, caribou from the Charlevoix population selected open stands older than 70 years of the following species: balsam fi r, balsam fi r-black spruce, black spruce, black-spruce-tamarack, and jack pine (Lefort et al. 2006). Caribou also selected dry bare land and stands of balsam fi r or fi r-black spruce 30 - 50 years, young jack pine 50 years, and dense stands of 70 years (Lefort et al. 2006). Sebbane et al. (2002) reported Charlevoix caribou selected mature conifer and arboreal and terrestrial lichens during winter.
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