Lecture 6 Flashcards
What is Landscape ecology?
Integrative study of the relationship between spatial patterns and ecological processes at various scales.
What are the core themes?
- Detecting and quantifying spatial patterns of
ecosystems (how does the ecology of different levels impact other levels) - Characterizing biotic and abiotic influences on those patterns (low does reduced rainfall effect forest growth)
- Understanding implications of those
patterns for populations and communities - Characterizing ecosystem patterns in space and time (how can seasonal changes in rainwater effect growth)
- Managing landscapes to achieve conservation and economic objective
What is a landscape?
- Landscapes varies tremendously in size
- The landscape for an ant is small (several square meters)
- Fox landscape can be up to tens of kilometres
- geographic boundaries
Landscape ecologists study ecology at coarse
scales (large scale) and fine scales (small scale)
Case study: tent caterpillars
- Case study: tent caterpillars that irrupt
periodically in temperate forests - They defoliate entire stands of aspen trees,
causing a serious ecological impact - # of aspens didn’t predict how long irruption was
- Instead, how fragmented the aspen trees are from each other predicted the length of irruption and how many tent caterpillars
- Caterpillar mobility is limited
Landscape ecology approach: measure
fragmentation as amount of forest
edge per km2 of habitat - make patches connect so caterpillars aren’t stuck in one spot
Patch
Contiguous area of similar habitat
- Patch shape influence ecology
- shape and size of patch influence ecological process
5 patches can have the same area
- but some could have no interior area
Edge
- Patches are bordered by edges! Area of steep transition between patches.
- Abrupt
Ecotones
Gradual transition between patches.
Interior
Central patch bounded by edge or
ecotone.
Corridor
Linear feature that differs from the area
on either side.
ex. river
* Natural (streams) or anthropogenic (roads)
* Corridors facilitate connectivity
* Populations in different patches connected by corridors are called metapopulation (Account for populations living in different patches)
disperse along linear corridors- If they do this then this creates a meta population
ex. chipmunk use corridors to move between patches They are a metapopulation
Network
Multiple corridors interacting together
ex. road and river
Series of interconnected linear elements, often
surrounding patches of another type
* Networks of hedgerows are an anthropogenic example
Ex. Ice-wedge ecosystems, lots of topography
Mosaic
An integrated complex of patches,
corridors and networks
- Everything working together
Corridors vs obstacles
Whether a linear feature is a corridor or obstacle depends on the organism
ex. A river can increase connectivity for some
organisms (as a corridor)(muskrat) and decrease it for others (as an obstacle) (rabbit)
Corridors and innovative experiments
- Grizzly bear, goes down to road then retreats
- our roads are an edge for this bear
- The populations are becoming genetically unique (less gene flow)
- Splitting single pop into metapopulation
- What does Canada do to help?
-Creating overpass and underpass for animals - landscape ecologists decide where to put corridors
The transitional zone between two adjacent
communities is called ___________________.
a.) a blended community
b.) a hybrid community
c.) an ecozone
d.) an ecotone
e.) none of the above
d.) ecotone
Which of the following statements about army-ants
are TRUE?
o Army-ants build a nest called a bivouac in a good foraging area, and remain in that location for their entire lives.
o Army-ants only take prey items that are smaller than themselves.
o Army-ant swarms play a key role in the community of ant-following birds.
o Army-ants forage solitarily but mate in large groups
with several hundred queens.
o All of the other statements are true.
o Army-ant swarms play a key role in the community of ant-following birds.
