Lecture week 13 (11-16) - Notes Community Ecology - Succession.docx

Community Ecology

The study of how species interact within a community and how the community as a whole functions and changes over time.

Species Diversity

The number and relative abundance of species in an area.

Species Richness

The number of different species in an area.

Succession

The gradual change in an area over time, including changes in species diversity and richness.

Primary Succession

Succession that occurs in areas where new substrates are created, such as by volcanoes or glaciers, and new soil must be formed.

Secondary Succession

Succession that occurs in areas where the community is diminished but the soil remains intact, such as after wind, fire, or logging.

Vegetative Succession

The form of succession that involves changes in vegetation over time, which can lead to predictable changes in other areas as well.

Climax

The late successional stage that a local community is expected to reach, often defined by the dominant species in that area.

Randomness

Events that occur randomly and can disrupt the predicted progression of succession.

History

The past events and conditions of an area that can influence the pathway of succession.

Facilitation

One species prepares the habitat for subsequent species to live in the same area.

Tolerance

Species show greater tolerance of abiotic factors and are better competitors for resources in later successional stages.

Inhibition

Early successional plants are inhibited by later successional plants in a mature community.

Stability

The ability of a community to resist abrupt changes in species diversity and richness.

Keystone Species

Species that have a greater impact on the diversity and species richness in their community than predicted based on their biomass.

Co-evolutionary Relationships

Relationships between species that add stability to a community by buffering each other from adverse effects.

Species Richness

The greater the number of species in a community, the greater the number of checks and balances on species numbers, and the less likely it is that the community will experience changes in species richness or composition.

stability in communities

1. co-evolutionary relationships

2. keystone species

3. species richness

three mechanisms describing succession

1. facilitation

2. tolerance

3. inhibition