Change in Communities - PCB 3043

These flashcards cover key concepts related to ecological communities and succession from the lecture notes.

Succession

The process of change in species composition and community structure over time following disturbance.

Primary Succession

Colonization of habitats devoid of all life, typically starting without soil.

Secondary Succession

Reestablishment of a community where most organisms have been destroyed but some life remains.

Climax Stage

The stable end point community that experiences limited change until a disturbance restarts the process.

Disturbance

An event that injures or kills individuals, creating opportunities for others to grow or reproduce.

Abiotic factors

Non-living environmental factors affecting ecosystems, such as waves and temperature.

Biotic factors

Living organisms and their interactions that affect ecosystems, such as predation and competition.

Facilitation Model

Early colonizers modify the environment in ways that benefit later colonizing species.

Tolerance Model

Initial colonizers modify the environment neutrally allowing later species to persist.

Inhibition Model

Early colonizers hinder later species from establishing by monopolizing resources.

Relative Interaction Intensity (RII)

A measure used to assess the impact of one species on another, calculated as (C – E)/(C + E), where C is the biomass of the target in presence of interactor and E is in absence.

Priority Effects

The phenomena where the first species to colonize influences subsequent community succession.

Alternative Stable States

A condition in which a community is disturbed and restructured, making it resistant to further change.

Ecosystem Engineers

Species that create, significantly modify, or maintain habitats.

Pioneer Species

Early successional species that colonize barren areas and often improve conditions for subsequent species.

R-selected Species

Species characterized by high reproduction rates and short life spans, adapted for rapid colonization.

K-selected Species

Species that invest more in fewer offspring and are adapted for stable environments.

Trophic Cascade

A process by which changes in the population of one species (e.g., predators) lead to indirect effects on other species at lower trophic levels.

Ecosystem Resilience

The ability of an ecosystem to recover from disturbances.

Diversity,

The variety of species in a given ecosystem, often measured in terms of species richness and evenness.

Community Structure

The composition and abundance of various species present in a community.