Ecology/Main Glossary

<<< << Chapter 1 | Glossary 1 |

A Glossary of Terms Related to Basic Ecology

Biological control or biocontrol: 1. In general, the control of the numbers of one organism as a result of natural predation by another or others. Specifically, the human use of natural predators for the control of pests or weeds. Also applied to the introduction of large numbers of sterilized males of the pest species, whose matings result in the laying of infertile eggs (Allaby, 1998). 2. The release of one species to control another (Carlton, 2001). 3. The management of weeds using introduced herbivores (often insects) as biological control agents (Booth et al., 2003). 4. Control method involving a biological control agent that is a natural enemy of a target pest (Heutte and Bella, 2003).

Biological diversity or biodiversity: Used to describe species richness, ecosystem complexity, and genetic variation (Allaby 1998).

Bioregion: A biological subdivision of the earth’s surface delineated by the flora and fauna of the region (Allaby 1998).

Biota: The plants and animals of a specific region or period, or the total aggregation of organisms in the biosphere (Allaby 1998). Community: Any grouping of populations of different organisms that live together in a particular environment (Allaby 1998).

Disturbance: An event or change in the environment that alters the composition and successional status of a biological community and may deflect succession onto a new trajectory, such as a forest fire or hurricane, glaciation, agriculture, and urbanization (Art 1993).

Ecosystem: A discrete unit, or community of organisms and their physical environment (living and non-living parts), that interact to form a stable system (Allaby 1998).

Endemic: A species or taxonomic group that is restricted to a particular geographic areas because of such factors as isolation or response to soil or climatic conditions; this species is said to be endemic to the place (Allaby 1998) and would be native.

Exotic species: This term is commonly used in publications and literature, and is similar to the terms alien species, foreign species, introduced species, non indigenous species, and non native species (Heutte and Bella 2003). Other definitions include: 1. An introduced, non native species, or a species that is the result of direct or indirect, deliberate or accidental introduction of the species by humans, and for which introduction permitted the species to cross a natural barrier to dispersal (Noss and Cooperrider 1994). 2. In North America, often refers to those species not present in a bioregion before the entry of Europeans in the 16th century, or present in later parts of that region and later introduced to an ecosystem by human-mediated mechanisms (Cohen and Carlton 1988).

Fauna: The animal life of a region or geological period (Allaby 1998)

Fitness: Survival and reproduction ability of an individual

Flora: Plant or bacterial life forms of a region or geological period (Allaby 1998).

Habitat: 1. The place, including physical and biotic conditions, where a plant or an animal usually occurs (Allaby 1998). 2. The physical conditions that surround a species, or species population, or assemblage of species, or community (Clements and Shelford, 1939).

Indigenous: A species that occurs naturally in an area; a synonym for native species (Allaby 1998), although see "endemic".

Native range: The ecosystem that a species inhabits (Booth et al. 2003).

Native species: 1. A synonym for indigenous species 2. A species that occurs naturally in an area, and has not been introduced by humans either intentionally or unintentionally (Allaby 2005). 3. In North America, a species established before the year 500 (Jeschke and Strayer 2005)

Naturalized species: 1. A species that was originally introduced from a different country, a different bioregion, or a different geographical area, but now behaves like a native species in that it maintains itself without further human intervention and now grows and reproduces in native communities (Allaby 1998). 2. A non native species that forms self-sustaining populations but is not necessarily an invasive species (Booth et al. 2003).

Niche: the role the species plays in the functioning of the ecosystem: the "functional status of an organism in its community" (Charles Elton, in Odum, 1959).

Population: A group of potentially inter-breeding individuals of the same species found in the same place at the same time (Booth et al. 2003).

Ruderal species: A plant associated with human dwellings, construction, or agriculture, that usually colonizes disturbed or waste ground. Ruderals are often weeds which have high demands for nutrients and are intolerant of competition. See also native weed or invasive native (Allaby 1998).

Species:  A group of organisms formally recognized as distinct from other groups; the taxon rank in the hierarchy of biological classification below that of genus; the basic unit of biological classification, usually defined by the reproductive isolation of the group from all other groups of organisms (Allaby 1998).

Weed: 1. A plant in the wrong place, being one that occurs opportunistically on land or in water that has been disturbed by human activities (see also ruderal species and native weed or invasive native), or on cultivated land, where it competes for nutrients, water, sunlight, or other resources with cultivated plants such as food crops. Under different circumstances the weed plant itself may be cultivated for beneficial purposes (Allaby, 1998). 2. A native or introduced species that has a perceived negative ecological or economic effect on agricultural or natural ecosystems (Booth et al., 2003). 3. A plant growing in an area where it is not wanted (Royer and Dickinson, 1999).