Boreal Forest Flashcards
What are some characteristics of the boreal forest?
High levels of relief, continuous forest virtually everywhere, lies entirely on the Canadian Shield, southern boundary of Great Lakes, St. Lawrence Forest Region (characterized by a mix of southern and northern trees)
+1 to -3 average daily temperature: warmer, longer growing season, more decomposition means more soil
More precipitation than the HBL, more diversity
Many different types of material deposited by glaciers, varying levels of drainage and nutrient density - mineral/organic soil on top of clay deposits
Coming in from another ecological zone, what is one way you could tell you have entered the boreal forest?
The absence of white and red pines, which have clustered needles
What are the regions of the boreal forest?
Eastern boreal, western prairie boreal, clay belt boreal, superior boreal (as in Lake Superior)
What are the main types of trees in the boreal forest? Describe their shape.
Spruce trees: single, round needles - black spruce is tall and spindly with sparse branches, white spruce is more fragrant and has a fuller body
Balsam fir: spire-shaped with a pointed top, needles like flat on the branch, smooth grey bark with bumps full of resin
Tamarack/larch: not an evergreen - turns from green to gold in the fall and drops its needles
In the boreal forest, what does a cluster of conifers suggest about the area? What types of conifers are found in the boreal?
A cluster of conifers, such as poplar, white birch, or trembling aspen, is indicative of a disturbance in the area which destroyed the trees, allowing sun to come in and sun-loving trees to grow - fire, insects, human destruction, etc.
Describe the importance of conifers in the boreal forest.
Conifers are an important food source for many animals in the boreal. Snowshoe hare, spruce grouse, sawfly larvae, and spruce budworm feed on the needles. In the winter, balsam fir is the main food source for moose. White-winged crossbill and boreal chickadee consume the seeds. The Canada jay stores seeds under loose bark or lichen on spruce trees for the winter. Red squirrels store cones in middens and eat the seeds in winter.
What is niche partitioning? Give an example of niche partitioning in the boreal forest.
Niche partitioning is an adaptation where multiple species consume the same food source at different times of day.
Example: great grey owl (crepuscular - dawn and dusk), northern hawk owl (diurnal -day), and boreal owl (nocturnal - night)
Describe the deer mouse found in the boreal forest.
Few adaptations to the cold: small ears, long tail
Use subnivean space - a layer of snow where ice crystal form - to avoid predators, keep warm, and hibernate
Describe the behaviour of the Canada (grey) jay.
Canada jays are permanent residents - they do not migrate. They store seeds under loose bark and lichen on spruce trees for the winter - a behaviour called ‘scatter hoarding’ - using sticky saliva. They are able to recall the locations thanks to their large hippocampus, which gives them a highly developed spatial memory. They nest in February, and by the time migratory birds are just laying eggs, their young are getting ready to leave the nest. The dominant young kicks out the less dominant siblings, and will stay in the parents’ territory in the nest all winter.
Briefly explain the cycle of boreal forest fires and the important of each stage.
- Budworms feed on trees, at times killing large tracts of forest
- Dead trees increase the risk of forest fire
- After forest fire, insects which feed on dead trees move in - jewel beetles can detect smoke, and longhorn beetles can detect jewel beetle pheromones
- Woodpeckers nest in dead trees to feed on insects
- Cavity adopters move into abandoned woodpecker nests
- New growth after forest fires attracts small mammals, which attract predators
- Blueberry and elderberry thrive in burnover areas - favourite food of bears
- Sun-loving trees such as poplar can now grow - beavers love poplar, build dams, area floods to create beaver pond
- Beaver ponds are nutrient sinks, allow water lilies and water shields to flourish
- Moose consume marine plants for sodium, store salt in their rumen for the entire year
What are the northern strippers and what is different between the two species?
Two species of woodpecker than strip the bark off trees, rather than peck holes:
American three-toed woodpecker: shorter bill, mostly eat beetles under bark
Black-backed woodpecker - longer bill, can feed on longhorn beetles deep in the wood
Which insects feed on poplar leaves in the boreal forest?
Serpentine miners: live within leaves and consume material between membranes, leaving splotches that look like snakes
Canadian tiger swallowtail: caterpillar’s markings look like eyes for defence, butterflies use proboscis to find minerals in puddles (puddling)
Forest tent caterpillar: can defoliate leaves, sometimes kills large tracts of trees
Name the three beetles that feed on bark in the boreal forest, and describe how to tell them apart.
Bark beetles: chew wood in fine, symmetrical patterns
Flat-headed borer grub/jewel beetle: chew wide, singular paths through wood
Longhorn beetle: feed deep in the wood
What is the significance of the colour of the white-throated sparrow?
Two colour morphs: tan-striped head, and white-striped head
Most pairs of these sparrows have one of each: the white is more defensive of territory, the tan is more maternal, meaning they make well-rounded parents, higher success of raising young
Which species make up the budworm warblers? Explain niche partitioning using this group.
Cape May warbler - gleans caterpillars at tips of branches at the top of the tree
Bay-breasted warbler - slow-moving and methodical, works through needle tangles mid-tree
Tennessee warbler: gleans outer branches at all heights
