Lecture 31- Plant Animal Interactions Flashcards
What are the two types of plant-animal interactions?
- Antagonistic = herbivory
- Mutualistic = pollination
What are some examples of co-evolution?
- Plant defenses
- Pollination
- Dispersal
Existing relationships are _______
Sensitive
Why are relationships sensitive?
- Short food webs
- Introduction of new species difficult
- Interact with few species
- Limited resources
Describe the web from lichen and Arctic willow to Arctic wolf
What does shrub encroachment onto tundra do?
- Outcompetes tundra plants
- Reduces biodiversity
- Removes species distribution eveness, get huge amount of one or two species
Can berbivores reduce shrub density?
Yes (but browsing stress to reach a limit)
How many caribou are required to reduce shrub density?
Requires 5 caribou per km^2
What are some effects of microtines on shrubs?
- Exert grazing pressure on dwarf shrubs
- Reduce crowberry
- Less shrub cover allowing for more permafrost thaw and more carbon release
- Evergreen shrubs reduce warming and carbon release
- Declines in lemming population fluctuations
Rare plants in the Arctic require ?
Specialized habitats
Rare plants become ____ with climate change
More rare
____ reduces common species
Grazing and trambling
____ reduces rare species
Herbivore exclusion
Describe how caribou increase permafrost
- Dig for lichens under the snow
- Reduce snow cover (insulating layer)
- Ground freezes more deeply
- Localized effect
Describe how caribou can decrease permafrost
- At high densitites caribou can increase permafrost thaw
- Lower soil insualtion
- Pooling of water (decreased albedo)
- Accelerated permafrost thaw
Describe the goose herbivory interaction
- Snow geese overgraze vegetation (also trample soil)
- Reduction in vegetation = loss of arthropod community
- Warmer soil temperatures
- Drier soils
- Shift of arthropod community to boreal species
What pollinates white and yellow flowers?
Pollinated by flies
What pollinates blue and purple flowers?
Pollinated by bumblebees
____ pollinator diversity in the north
Low
What predicts pollinators?
Flower colour
What colour of flowers are in low and high abundance?
- Low = blue/purple
- High = white/yellow
Why have yellow and white flowers?
- Flies attracted to yellow and white
- Lower energetic cost
What colour of flowers would you find in glaciated and glacial refugia regions?
- Glaciated = yellow/white
- Glacial refugia = blue/purple
Describe the relationship between carnivores and arctic plants
- Biopedturbation = animal caused soil disturbance
- Digging by grizzly bears = changes in soil moisture
- Burrowing by ground squirrels = patch of exposed soil that will be drier
- Maintains ecosystem heterogeneity or patchiness = increase plant species diversity
