Definition: Common species and uncommon species are designations used in ecology to describe the population status of a species. Commonness is closely related to abundance. Abundance refers to the frequency with which a species is found in controlled samples; in contrast, species are defined as common or uncommon based on their overall presence in the environment. A species may be locally abundant without being common.
Definition: Stress tolerant species live in areas of high intensity stress and low intensity disturbance. Species that have adapted this strategy generally have slow growth rates, high rates of nutrient retention, and low phenotypic plasticity. Stress tolerators respond to environmental stresses through physiological variability. These species are often found in stressful environments.
Definition: Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality.
Definition: A group of species that exploit the same food resources, and/or use the same feeding or foraging methods. http://en.wikipedia.org/wiki/Guild_(ecology)
