Lecture 4 Flashcards
Breeding range of birds; where is this confined to in the tundra?
Southern limits of where they nest; Hudson Bay coastline
Most birds in the tundra are ground-dwelling, such as these birds with a long toenail for digging up seeds & invertebrates
Longspurs (Smith’s, Lapland)
Birds sing while _____ to ____
flying to mark their territory
Most birds head south for the winter, except for ____, which stays year-round
Willow ptarmigan, a northern grouse; feathered legs/feet/toes help them stay warm
Challenges for plants growing in the tundra
Abrasive wind
Cold, permafrost
Lack of nutrients
Short growing season (<140 days)
This plant is dominant in the tundra:
Saxifrages
Plant adaptations in the tundra
Cold hardiness (ice forms in structure) Small size Low/creeping/sprawling growth Clump growth Retains leaves year-round Dark colours Hair to absorb/trap heat Growing in sheltered sites (e.g. crevices)
3 trees that exhibit dwarfism
Dwarf Birch, Arctic Willow, Labrador Willow
Genotypic Dwarfism
Fixed genetically to be a certain size (e.g. Dwarf Labrador Tea wouldn’t grow larger if planted further south)
Phenotypic Dwarfism
Size depends on environment (e.g. Dwarf Birches grow larger if planted further south)
These formations protect plants from harsh conditions
Raised beach ridges
Thicket
area where shrubs form a dense growth pattern; habitat for insect-gleaning birds (e.g. warblers) and migratory songbirds that don’t nest on the ground
Layering + cold temperatures
Tree branch touches the ground, and a new tree grows from it - spruces (e.g. white spruce)
Layering at the base of a tree is covered by snow, while the dead top part is the only part exposed to the harsh conditions
Tundra-nesting birds (4):
Blackpoll Warbler (also in HBL)
Common Redpoll (live in willow thickets)
Hoary Redpoll
American Tree Sparrow (at the tree line)
Small mammals that depend on thickets (2)
Meadow voles
Northern bog lemming
Why aren’t deer mice found in the tundra?
Long tail & big ears aren’t suited for cold temperatures
Why are meadow voles & northern bog lemmings able to survive in the tundra?
Short tail/ears, plump bodies
Bergmann’s Rule
Larger species are found in colder environments
Gloger’s Rule
Species with less pigment (i.e. white colouration, inc. in winter) are found in colder environments
Allen’s Rule
Animals in cold environments have smaller extremities
What is the long-tailed mouse species found in the tundra, and how does it survive?
Meadow jumping mouse, survives by burrowing into beach ridges and hibernating
Name an animal (other than meadow jumping mouse) that survives by hibernating in the tundra
Groundhog
Meadow vole population cycles
Meadow voles are very rare in some years and abundant in others; this affects the populations of their predators (arctic fox, short-eared/snowy owls, northern harriers)
Snowy owls
- Dense feathers, turn white with age
- Feathers over bill protect from winds
- Females are larger and tend to have dark markings
- Most northern owl in the world
- Kill lemmings and pile them around nests to feed babies when they hatch
