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of terms related to the biodiversity



Earth Summit, Rio de Janeiro

Popularly known as the 'Earth Summit', the United Nations Conference on Environment and Development (UNCED) held on 3-14 June 1992, in Rio de Janeiro, Brazil, marked the twentieth anniversary of the United Nations Conference on the Human Environment held in Stockholm, Sweden, in 1972. Virtually every country in the world was represented (178) and more than 100 heads of state attended. The participating world leaders signed five major instruments: - The Rio Declaration (a statement of principles) (http://www.un.org/documents/ga/conf151/aconf15126-1annex1.htm); - Agenda 21 (a framework for activity into the 21st century addressing the combined issues of environment protections and fair and equitable development for all, and includes the creation of a new Commission for Sustainable Development) (http://www.un.org/esa/sustdev/documents/agenda21/english/agenda21toc.htm); - Framework Convention on Climate Change (http://unfccc.int/ ); - Framework Convention on Biological Diversity (http://www.biodiv.org/ ); - Statement of Principles on Forests (http://www.un.org/documents/ga/conf151/aconf15126-3annex3.htm).

ecological economics

A branch of economics that takes account of ecological principles and examines economic values of non-market ecological products and services.

ecological or ecosystem resilience

Ecological resilience can be defined in two ways. The first is a measure of the magnitude of disturbance that can be absorbed before the (eco)system changes its structure by changing the variables and processes that control behaviour. The second, a more traditional meaning, is as a measure of resistance to disturbance and the speed of return to the equilibrium state of an ecosystem.

ecological or ecosystem services

Ecological or ecosystem processes or functions which have value to individuals or to society.


A branch of science concerned with the interrelationship of organisms and their environment.


- The organisms of a particular habitat, such as a pond or forest, together with the physical environment in which they live; a dynamic complex of plant, animal, fungal, and microorganism communities and their associated non-living environment interacting as an ecological unit. Ecosystems have no fixed boundaries; instead, their parameters are set according to the scientific, management, or policy question being examined. Depending upon the purpose of analysis, a single lake, a watershed, or an entire region could be an ecosystem. - The organisms living in a given environment, such as a tropical forest, a coral reef or a lake, and the physical part of the environment that impinges on them. - A complex of organisms and their environment, interacting as a defined ecological unit (natural or modified by human activity, e.g. agroecosystem), irrespective of political boundaries. - A community of organisms in their physical environment.

ecosystem diversity

- The diversity among biological communities and their physical settings, characterised by differences in species composition, physical structure, and function. It is the highest level of biological diversity. - The variety of ecosystems (ecosystem) that occurs within a larger landscape, ranging from biome (the largest ecological unit) to microhabitat.

ecosystem rehabilitation

The recovery of specific ecosystem services(ecosystem service)in a degraded ecosystem or habitat.

ecosystem restoration

The return of an ecosystem to its original community structure, natural complement of species, and natural functions.


Travel undertaken to witness sites or regions of unique natural or ecologic quality, or the provision of services to facilitate such travel.


A genetically differentiated subpopulation that is restricted to a specific habitat.

edge effect

Processes that characterize habitat fragmentation and the concomitant creation of edges.

endangered-maintained breed and critical-maintained breed

Categories where critical breeds or endangered breeds(endangered breed) are being maintained by an active public conservation programme or within a commercial or research facility.

endangered breed

A breed where the total number of breeding females is between 100 and 1,000 or the total number of breeding males is less than or equal to 20 and greater than five; or the overall population size is close to, but slightly above 100 and increasing and the percentage of pure-bred females is above 80 percent; or the overall population size is close to, but slightly above 1,000 and decreasing and the percentage of pure-bred females is below 80 percent.

endangered species

- A technical definition used for classification in the United States referring to a species that is in danger of extinction throughout all or a significant portion of its range. - IUCN The World Conservation Union (http://www.iucn.org/ ) definition, defines species as endangered if the factors causing their vulnerability or decline continue to operate.

endemic bird area (EBA)

A term used by BirdLife International (http://www.birdlife.net/ ) to describe areas with two or more restricted- range bird species entirely confined to them

environmental impact assessment (EIA)

- Process by which the consequences of proposed projects or programs are evaluated as an integral part of planning the project, alternatives are analysed, and the general public has ample opportunity to comment. - A method of analysis which attempts to predict the likely repercussions of a proposed major development (usually industrial) upon the social and physical environment of the surrounding area.


Referring to the top 200 meters of the ocean, seas and lakes.

equilibrium theory

- Theory that suggests that under natural circumstances, species addition and loss are balanced, and furthermore, that displacement from the equilibrium value results in changes in speciation or extinction rate that tend to restore the system to its equilibrium state. - A theory of island biogeography maintaining that greater numbers of species are found on larger islands because the populations(population) on smaller islands are more vulnerable to extinction. This theory can also be applied to terrestrial analogues such as forest patches in agricultural or suburban areas or nature reserves where it has become known as ‘insular ecology.’


Application of phytosanitary (and other) measures to eliminate a pest from an area.


An ecosystem in which a river or stream meets ocean waters; characterised by intermediate or variable salinity levels and often by high productivity.

ethical values

Statements of ethical principle that inform the private and social valuation of biological resources(resource).


Study of the way plants, animals and microorganisms are used by humans.

eukaryote (opp.: prokaryote)

An organism whose DNA is enclosed in nuclear membranes. The vast majority of species (plants, animals, protista,...) are eukaryotic.


Process by which a lake, a river, part of a sea etc. is enriched with nitrates, phosphates and other nutrients (often from human sources such as agriculture, sewage, and urban runoff) which favour the growth of algae and often kill other organisms by lack of oxygen.


Any gradual change. Organic evolution is any genetic change in organisms from generation to generation.

ex-situ (opp.: in-situ)

- Out of the original location. In conservation- often in a laboratory, collection, botanical garden, zoo, or aquarium. - Pertaining to study or maintenance of an organism or groups of organisms away from the place where they naturally occur. Commonly associated with collections of plants and animals in storage facilities, botanic gardens or zoos.

ex-situ conservation

- Keeping components of biodiversity alive away from their original habitat or natural environment. - A conservation method that entails the removal of germplasm resources (seed, pollen, sperm, individual organisms), from their original habitat or natural environment.

ex situ conservation of farm animal genetic diversity

All conservation of genetic material in vivo, but out of the environment in which it developed, and in vitro including, inter alia, the cryoconservation of semen, oocytes, embryos, cells or tissues.

exclusive economic zone

That part of the marine realm seaward of territorial waters within which nations have exclusive fishing rights.

existence value

The value of knowing that a particular species, habitat or ecosystem does and will continue to exist. It is independent of any use that the valuer may make of the resource.


- Not native to a given area; either intentionally transplanted from another region or introduced accidentally. - In plant breeding, it refers to plants types that are from outside a breeding region or exhibit traits that are uncommon to the prevalent crop plant type.

exotic species (see: alien species)

An organism that exists in the free state in an area but is not native to that area. Also refers to animals from outside the country in which they are held in captive or free-ranging populations(population).

extant (opp.: extinct)

Still living at the present time.

extinct breed

A breed where it is no longer possible to recreate the breed population. Extinction is absolute when there are no breeding males (semen), breeding females (oocytes), nor embryos remaining.


- The death of any lineages of organisms. Extinction can be local, (when it is known as extirpation) in which one population of a given species vanishes while others survive elsewhere, or total, in which all its populations vanish. - The evolutionary termination of a species caused by the failure to reproduce and the death of all remaining members of the species; the natural failure to adapt to environmental change. - Disappearance of a taxonomic group of organisms from existence in all regions.

extractive reserve

Forest area for which use rights are granted by governments to residents whose livelihoods customarily depend on extracting forest products from the specified area.

extreme environments

Environments characterised by extremes in growth conditions, including temperature, salinity, pH, and water availability, among others.


A microorganism whose optimum growth is under extreme conditions of temperature, etc.

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