Biotic Communities and Disturbance Regimes in the Canadian Shield
Biotic Communities
Baffin Island
The vegetation of the Canadian Arctic is the tundra. Plants species in the tundra are very limited and the length of their growing season is short. Cotton grass, sedge, dwarf heath, shrubs, mosses and lichens are the most common vegetation in the Canadian Arctic (Aun et al. 2002). Three types of ecosystems are contained in the Canadian Arctic: the Arctic Cordillera, Northern Arctic and Southern Arctic, with Baffin Island being in the Northern Arctic. Because of its harsh climate, high winds and shallow soils, the vegetation of the Northern Arctic is sparse and dwarfed (Aun et al. 2002). Life in the polar regions is far from easy. Winter temperatures can reach deep into the negatives, and the winter night can last for months (WWF). But these landscapes which are lacking in vegetation are home to a rich diversity of wildlife, both on land and under the sea surface (WWF).
1. Killer Whale (Ornicus orca)
(Source: NOAA Fisheries)
Range Map
(Source: The Garden of Eaden)
Killer whales are found in all oceans. While
they are most abundant in colder waters like Antarctica, Norway, and Alaska,
they are also found in tropical and subtropical waters (NOAA Fisheries).
2. Arctic Fox (Vulpes Lagopus)
(Source: World Wildlife Foundation)
Range Map
(Source:PBS)
The Arctic
fox is primarily a carnivore. It lives inland, away from the coasts, and is dependent on the presence of smaller animals (most often lemmings) to
survive (WWF). Arctic foxes also hunt for sea birds, fish, and other marine
life. Smaller rodent populations waver between times of abundance and scarcity,
which leaves the Arctic fox vulnerable when these creatures are low in numbers (WWF).
Montcerf-Lytton
Montcerf-Lytton is in a northern temperate biome zone, in a deciduous
forest subzone (Talbot, 2008). Temperate climates like this one do not experience extremes regarding temperature or precipitation. Deciduous forest subzones' primary vegetation consists of broadleaf trees like oaks, maple, and beeches, as well as shrubs, perennial herbs, and mosses (NASA).
1. Moose (Alces alces)
(Source: The Canadian Encyclopedia)
Range Map
(Source: PBS)
Moose are found in the northern regions of the
United States, throughout Canada, and into Alaska (NWF).
Due to their large size and insulating fur, moose are limited to cooler climates.
Forested areas with streams and ponds are ideal moose habitat (NWF). Moose are herbivores, and they are so tall that they have
difficulty bending down to eat grasses. For this reason, they prefer to feed on leaves, bark,
and twigs from trees and shrubs (NWF). They enjoy eating native willow,
aspen, and balsam fir trees, as well as aquatic plants from streams and
ponds (NWF).
2. Spruce Grouse (Falcipennis canadensis)
(Source: Audubon.org)
Range Map
(Source: sdakotabirds.com)
Spruce grouse live in birch and evergreen coniferous forests (DNR). These chickenlike birds eat mostly the needles
of fir, spruce, and pine, an aromatic diet that makes them unpalatable to many predators, including hunters (allaboutbirds.org). Females with
young use more open forest, which provides more ground cover for protection, as
well as more small plants and insect prey for the chicks (allaboutbirds.org). Grouse dispersing
from natal areas in the autumn sometimes frequent deciduous forests (allaboutbirds.org).
Big Falls, Minnesota
Big falls, MN is in a coniferous forest biome type (DNR). A coniferous forest contains evergreen trees
that bear cones. Elegant pines grow in this biome, along with spruce, fir, and tamarack (DNR). In most of the northern forest, the conifers coexist with deciduous trees, especially aspen, birch, sugar maple, and basswood (DNR). Conifers are well adapted to living in the
cold, and since their needles are retained for up to 15 years, they can begin
photosynthesis as soon as temperatures are warm enough (DNR).
1. Red-Tailed Hawk (Buteo jamaicensis)
(Source: Audubon.org)
Range Map
(Source: allaboutbirds.org)
Red-tailed hawks are common throughout the United States,
Canada, the Caribbean, and Mexico (thespruce.com). They exist in a wide range of habitats, including grassland, tundra, desert, marshes,
and forests. Red-tailed hawks can even adapt to suburban areas (thespruce.com). Canadian bird populations and those in the extreme northern United
States may migrate seasonally depending on weather severity and food supplies, but in most of their range, red-tailed hawks do not migrate (thespruce.com).
2. Snowshoe Hare (Lepus americanus)
(Source: Canadian Wildlife Federation)
Range Map
(Source: Canadian Wildlife Federation)
Ideal snowshoe hare habitat is in and around coniferous forests, but other prime habitat are near aspen,
spruce, and cedar swamps (Vermont Fish & Wildlife Department). The hare's dependence on conifer stands depends upon the hare's need for concealment (Vermont Fish & Wildlife Department). Small, scattered openings adjacent to the softwood cover, with
brushy deciduous vegetation for improve survival by reducing travel
distances to food (Vermont Fish & Wildlife Department). Forests that have been recently managed through techniques
such as thinning, cutting, or prescribed burning benefit hares because of their
abundance of natural regeneration (Vermont Fish & Wildlife Department).
Disturbance Regimes
Baffin Island
The primary concern facing tundra ecosystems is global climate change (seattlepi.com). Arctic temperatures
have risen three to five degrees over the past 50 years and models forecast
that this may double in the future. Warming temperatures thaw the permafrost,
allowing non-tundra plants to invade. Thawed permafrost no longer holds the
soil in place, so erosion also becomes a problem. Climate change has led to
larger and more frequent wildfires, such as the largest tundra fire in recorded
history in Alaska in 2007 (seattlepi.com)
Montcerf-Lytton, Quebec
Fire is an important natural disturbance factor
in many boreal forests, in savannah-type ecosystems, and also in high mountain
dry-land ecosystems (Fischer et al. 2013). It is associated with special adaptations like thick bark, the ability to
re-sprout after fire, or store seeds on the
tree until a fire occurs (Fischer et al. 2013). These kinds of
adaptations are missing in the tree species found in many deciduous temperate
forests, because they do not naturally experience frequent fire. Therefore, deciduous temperate forests are especially vulnerable to fire (Fischer et al. 2013)
In temperate coniferous forests, wind acts as a primary natural disturbance. When trees in these forests are bent and broken by a strong wind event, there is less protection for the trees remaining in the area, making them for vulnerable to the next wind event. However, species in coniferous forests that have experienced more wind events adapt to have stronger bark, as well as stronger root anchorage (Seidl et al. 2017). As is the case with fire, although it will not be evident in this generation of tree species in the forest, the more frequently a forest experiences wind events, the stronger defense they will have against them in the future.
Sources:
Fischer, A., Marshall, P. & Camp, A.
Disturbances in deciduous temperate forest ecosystems of the northern
hemisphere: their effects on both recent and future forest development. Biodivers Conserv 22, 1863–1893 (2013).
https://doi.org/10.1007/s10531-013-0525-1
Seidl,
R., Thom, D., Kautz, M., Martin-Benito, D., Peltoniemi, M., Vacchiano, G., …
Reyer, C. P. O. (2017). Forest disturbances under climate change. Nature Climate
Change, 7(6), 395–402. doi:10.1038/nclimate3303
http://www.sfu.ca/geog351fall02/gp2/WEBSITE/2_content_v.html
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