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What is the difference between extrinsic and intrinsic heterogeneity?
- extrinsic heterogeneity: heterogeneity is a feature of the environment
- intrinsic heterogeneity: heterogeneity is caused by the coupled action of environment and community
What are the consequences of different levels of disturbance?
- high- few species with the appropriate fundamental niche, reduced diversity
- intermediate- promote higher diversity
- low- high competition, reduced diversity
How can predators enable species coexistence?
- can keep species below carrying capacity
- competition exclusion unlikely
- therefore number of species high
What are metapopulations?
populations that are spatially structured into assemblages of locally breeding populations with dispersal among them
What are metacommunities?
communities that are connected through dispersal of some individuals
What are the different metacommunity paradigms?
- patch-dynamics- allows co-existence in region
- species sorting- dispersal allows shift in competition with environmental change
- mass effects- species maintained in unfavourable habitats
- neutral- occupancy is random, dependent on chance
What is a community?
an association of interacting species inhabiting some defined area
What is guild?
a group of organisms that all make their living in a similar way
What kind of curve do you use to measure species abundance?
species accumulation curve
What is evenness?
A measure of how evenly individuals are distributed among species independent of species number
Diversity is based on 2 measures...
- number of species
- species evenness
What mechanisms might increase species richness on large islands?