BIO 101, Chapter 41, Ecological Communities

Community

the assemblage of interacting individuals of different species within a particular geographic area

Species Composition

the identity of all the species that make up a given community

Turnover

the change through time or over space in the composition of an ecological community

Colonization and Extinction

new species arrive; residents may become extinct

Disturbance

events that cause sudden change in the environment and in ecological systems as a result (can be big or small)

Succession

the gradual change in a community after a disturbance as different organisms move in and replace others.

habitat struture

What a habitat looks like and what it is made of.

Community Function

the amount of energy or matter moving into or out of a community over a certain amount of time.

Flux

the exchange or movement of energy and materials between a community and its environment.

Gross Primary Productivity (GPP)

the rate at which plants and other producers use sunlight to make energy (food).

Net Primary Productivity (NPP)

the amount of energy plants store as new biomass after using some energy for themselves.

Measured by biomass

GPP=

NPP+Respiration

NPP=

GPP-R

Species Evenness

a measure of the similarity in the abundance of species in a community

Species Richness

a total number of species in an ecological community

Fragmentation

The division of a large habitat into smaller, isolated pieces separated by a different type of habitat.

Results of Habitat Fragmentation

-loss of species, lower species richness

-decreased colonization rates due to human-dominated landscapes that work as barrier to dispersal

Primary Succession

after major disturbance, starting from scratch, primary colonizers

Secondary Succession

still nutrients and some species remaining after disturbance

island biogeography

the study of how island size and distance from the mainland affect the number of species living on an island.

species diversity

The variety of different species in an ecosystem.

niche complementarity

when different species use different resources or parts of an environment, so they can live together with less competition.

ecosystem services

The benefits that people get from nature and ecosystems.

habitat fragmentation

When a large habitat is broken into smaller, separate pieces.

restoration ecology

The study and practice of helping damaged ecosystems return to a healthy state.

state transition

change from one state or condition to another.

pioneer species

The first organisms to live in an area after it has been disturbed or has no life.

Respiration

the process organisms use to break down food and release energy.