Lecture 9 Flashcards
Beaver tails - how do they benefit beavers?
- Steering/balance when floating
- Pumping blood into the tail lets them cool down in the summer
- Allows for conservation of heat in the winter
- Balance while sitting
- can warn other beavers of predators by slapping the tail
Why do beavers have orange teeth?
Iron oxides
T/F: beavers only eat plant material like poplar and aquatic plants (e.g. water lilies)
True
When are young beavers kicked out of the colony?
after 2 years
Plants in beaver ponds
- Root at the bottom, leaves/flowers float on the surface
- Leaves are eaten by insects & moose
Whirligigs
beetles on the water’s surface of beaver ponds
Midges
Type of fly found on the surface of beaver ponds
- larvae are in mud at the bottom of ponds
- form large mating swarms when many float to the surface
- food source for insects, birds, dragonflies, damselflies, etc near beaver ponds
T/F: beaver ponds are a lotic water system
False: no water current = lentic system
Since beaver ponds are lentic water systems, how does this benefit dragonflies?
They can just wait for food to pass by on water
What are skimmers?
Large-bodied dragonflies that skim over water to get food; associated with beaver ponds
Which group of animals lays eggs in beaver ponds?
Amphibians
T/F: some frogs live at the bottom of ponds in the winter
True
T/F: the mink frog is only found in the boreal forest
False
T/F: warmer water results in more biodiversity (i.e. more species)
True
These mammals live in lodges around beaver ponds:
Muskrats
T/F: most semi-aquatic/aquatic weasels have webbed toes to help them swim
False: hairs on feet create a larger surface area, helping them swim
T/F: beaver ponds support a large ecosystem with lots of plants/animals
True
River otters
Aquatic weasel
- eat frogs, fish
- short legs, large hind feet
- streamlined shape helps with swimming
- confined to freshwater
What happens when a beaver dam breaks (after the beavers leave/die)? What type of habitat develops?
- nutrient-rich mud at the bottom is exposed to air
- plants colonize the area (e.g. sedges)
- beaver meadow develops
Why are beaver meadows also known as rendez-vous sites?
Adults wolves will leave their pups there to play and bring back food
Which animal uses beaver meadows as mating sites?
Moose
How do beavers indirectly help moose?
- Creation of beaver meadows
- Beaver ponds have sodium-rich plants
What can happen to trees after a dam goes up? How do other species benefit?
They get flooded and die; become habitat for fungi, beetles, woodpeckers
Do beaver ponds increase or decrease a region’s biodiversity?
Increase
