2.5

Zonation

The change in community composition along a spatial environmental gradient. Examples include changes with altitude up a mountain or distance from a shoreline.

Succession

The process of change in the species structure of an ecological community over time. It is a temporal phenomenon, as opposed to a spatial one.

Environmental Gradient

A gradual change in abiotic factors through space. Zonation occurs along these gradients.

Transect

A line used in ecological sampling to investigate changes along an environmental gradient. It is the primary method for studying zonation.

Kite Diagram

A graphical representation used to show the distribution and abundance of species along a transect.

Primary Succession

The sequence of community changes that occurs on a newly formed, lifeless substrate where no soil or pre-existing community exists (e.g., bare rock after a volcanic eruption).

Secondary Succession

The sequence of community changes that occurs in an area that has been disturbed but where soil is already present (e.g., a forest after a fire, an abandoned field).

Pioneer Community

The first group of hardy species, typically lichens and mosses, to colonize a barren area at the start of primary succession. They are responsible for initial soil formation.

Seral Community (Sere)

An intermediate stage in an ecosystem's succession. Each sere modifies the environment, paving the way for the next community.

Climax Community

The final, stable, and self-perpetuating community that is in equilibrium with its environment. It has high biodiversity and complex food webs.

Changes During Succession

As succession proceeds, there is typically an increase in species diversity, soil depth, biomass, productivity, and ecosystem stability.

Ecosystem Stability & Resilience

An ecosystem's capacity to tolerate disturbances and maintain equilibrium. This generally increases as succession progresses due to greater diversity and complexity.