The State of Canada's Environment — 1996

Glossary of Selected Terms - C

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Sources for definitions

canopy (tree): The more-or-less continuous cover of branches and foliage formed by the crowns of adjacent trees (Natural Resources Canada 1994).

carbon balance: The concentration of carbon released into the atmosphere compared with the amounts stored in the Earth's oceans, soil, and vegetation (Natural Resources Canada 1994).

carbon dioxide: One of the greenhouse gases, which is released to the atmosphere by both natural and human activities. Although it is reabsorbed by the biosphere in 50-200 years, while in the atmosphere it is an effective radiator of energy and contributes to the greenhouse effect (Environment Canada 1995).

carbon monoxide (co): A colourless, odourless, and tasteless gas released primarily by incomplete combustion of fossil fuels (especially by automobiles). At low doses, carbon monoxide impairs reflexes and perception; at high concentrations, it can cause unconsciousness and death (Greater Vancouver Regional District 1994).

cfcs (chlorofluorocarbons): Any of several simple gaseous compounds that contain carbon, chlorine, fluorine, and sometimes hydrogen. Several forms of these gases are artificially produced and have been used as refrigerants, aerosol propellants, and cleaning solvents and in the manufacture of plastic foam. They are suspected of causing ozone depletion in the stratosphere and, being effective radiators of energy, are strong greenhouse gases.

chlor-alkali plants: Plants that produce chlorine and caustic soda by electrolysis of brine (adapted from Eade 1994).

chlorinated organic compounds: See organochlorine compounds.

chlorophenols: (also known as chlorinated phenols) Group of toxic chemicals created by the chlorination of phenols (e.g., pentachlorophenol). Used as preservatives in paints, drilling muds, photographic solutions, hides and leathers, and textiles. Also used as herbicides and insecticides and, most commonly, for wood preservation (Wells and Rolston 1991).

chronic toxicity: A measurable, but not totally disabling, effect produced in an organism by a substance over a relatively long period (Demayo and Watt 1993). The end result of chronic toxicity can be death, although the usual effects are sublethal (e.g., inhibition of reproduction or growth).

clear-cutting: A forest management practice that involves the complete felling and removal of a stand of trees (Natural Resources Canada 1994). Clear-cutting may be done in blocks, strips, or patches.

climate change: An alteration to measured quantities (e.g., precipitation, temperature, radiation, wind, cloudiness) within the climate system that departs significantly from previous average conditions and is seen to endure, bringing about corresponding changes to ecosystems and socioeconomic activity (Environment Canada 1995).

climate element: A discrete, perceptible, and measurable property of climate, such as temperature, rainfall, wind, and cloudiness (Environment Canada 1995). A "derived element" is an element computed from an observed climate element. For example, "the growing season" is derived from measurements of temperature.

climate fluctuation: A climatic event (e.g., a cold summer) that may be perceived initially as a beginning of climate change but later, as conditions revert to the previous regime, is understood to be a short-term occurrence (Environment Canada 1995).

climax species: Species of trees or other vegetation often found in a forest ecosystem at the final stage of its development (Natural Resources Canada 1994).

coliform bacteria: Group of bacteria predominantly inhabiting the intestinal tracts of humans and other warm-blooded animals, but also occasionally found elsewhere (Demayo and Watt 1993). The total coliform group is commonly used as an indicator of the sanitary quality of water, because ingestion of these bacteria in drinking water can result in diseases such as cholera.

commons: Originally referred to lands in medieval Europe that were owned by townships rather than by private individuals. Now used to include any exploitable resource that is not privately owned (Meffe et al. 1994).

compliance monitoring: Surveillance to ensure conformity to a law, regulation, or guideline (Demayo and Watt 1993).

conservation: The maintenance or sustainable use of the Earth's resources in a manner that maintains ecosystems, species and genetic diversity and the evolutionary and other processes that shaped them. Conservation may or may not involve the use of resources; that is, certain areas, species or populations may be excluded from human use as part of an overall landscape/waterscape conservation approach. (Federal-Provincial-Territorial Biodiversity Working Group 1995).

contamination: Introduction of any undesirable foreign substance - physical, chemical, or biological - into an ecosystem. Does not imply an effect (see pollution). Usually refers to the introduction of human-made substances (adapted from Wells and Rolston 1991).

core zone: Within a larger protected area (reserve, park, etc.), an area of critical importance in which development and other kinds of disruptive activities are prohibited (Meffe et al. 1994).

corridor: With respect to ecosystems and ecosystem functions, the naturally vegetated or potentially revegetated areas that link or border natural areas and provide ecological functions such as hydrological flow, habitat, passage, connection, or buffering from impacts due to activities in adjacent areas (adapted from Ontario Ministry of Municipal Affairs 1994). Corridors can occur across or along uplands, lowlands, or slopes; valley, ravine, and river or stream corridors can exist as landform depressions that usually have water flowing through or standing in them for some period of the year.

country food: A diet of local meat and fish (e.g., seal, whale, Caribou, and Arctic Charr) and wild plants gained through subsistence harvest (adapted from Environment Canada 1994).

cumulative effect: The effect on the environment that results from the incremental impact of a proposed action when added to other past, present, and reasonably foreseeable future actions (Kaufmann et al. 1994).