Compare and contrast the equilibrial and nonequilibrial models of community dynamics.. Ecology

Equilibrial model of community dynamics

• The classic model which states that communities are in equilibrium
• Species abundance remains constant over time - it is in a state of stable equilibrium
• Stability can be measured by the time it takes to recover from disturbance. Stable communities recover quickly from disturbances.
• Stability can also be measured by the variability of a community, if the community structure remains constant over time then it is stable. It can be a measure of the persistence of a community.
• Such a community would have many biotic interactions involving predation and competition.
• Such communities would be saturated in species richness, meaning that it holds the maximum possible number of species. This means that invasions are rare.
• Rarely weather catastrophes occur in these communities.

Nonequilibrial model of community dynamics

• By contrast this model states that communities would score low on all the above measures of stability.
• Extreme weather events would occur frequently in these systems.

Real communities are spread along an spectrum from equilibrium to nonequilibrium