Chapter 9 Flashcards
Communities
Metapopulation
Group of populations (of the same species) that are connected by immigration/emigration.
Patch
A cluster of the same species.
Disturbance
A temporary change in environmental conditions that causes a change in an ecosystem (e.g. fire, windstorms, volcanoes, etc.).
Gap
Patches within which many species suffer local extinction simultaneously.
Founder-controlled community
Communities where species are approximately equivalent in their ability to invade gaps and can hold the gaps against all comers during their lifetime.
Priority effect
Species that arrives first at a site is able to hold it against competing invaders.
Dominance-controlled community
Communities where some species are competitively superior to others, and initial colonizers may not maintain their presence.
Community succession
Early species are good colonizers and fast growers, but later species can eventually outcompete them.
Climax stage
The point at which community’s most efficient competitors oust their neighbors. The final stage of succession that is thought to be stable.
Primary succession
Sequence of ecosystem development without influence from prior community (e.g. bare ground without any seeds underground).
Secondary succession
Sequence of ecosystem development with influence from prior community (e.g. seeds, soil).
Chronosequence
A series of distinct sites of varying ages that is assumed to represent a sequence of succession (e.g. the land uncovered by a receding glacier).
Food web
The complex web of interactions between species’ within a community.
Trophic cascade
Predators suppress the abundance or alter the behavior of their prey, thereby releasing the next lower trophic level from predation.
Top predator
A predator that occupies the highest trophic level (i.e. has no natural predators).
