Species An interbreeding group of organisms that is reproductively isolated from all other organisms,
although there are many partial exceptions to this rule in particular taxa. Operationally, the term
species is a generally agreed fundamental taxonomic unit, based on morphological or genetic
similarity that once described and accepted is associated with a unique scientific name.
Species diversity Biodiversity at the species level, often combining aspects of species richness, their relative abun-
dance and their dissimilarity.
Species richness/
abundance
The number of species within a given sample, community or area.
Surface water All water naturally open to the atmosphere, including rivers, lakes, reservoirs, streams, impound-
ments, seas and estuaries. The term also covers springs, wells or other collectors of water that are
directly influenced by surface waters.
Sustainability A characteristic or state whereby the needs of the present and local population can be met without
compromising the ability of future generations or populations in other locations to meet their needs.
Sustainable develop- Development that meets the needs of the present generation without compromising the ability of
ment future generations to meet their own needs.
Technology Physical artefacts or the bodies of knowledge of which they are an expression. Examples are water
extraction structures, such as tube wells, renewable energy technologies and traditional knowledge.
Technology and institutions are related. Any technology has a set of practices, rules and regulations
surrounding its use, access, distribution and management.
Technology transfer A broad set of processes covering the flows of know-how, experience and equipment among differ-
ent stakeholders.
Threshold A point or level at which new properties emerge in an ecological, economic or other system, invali-
dating predictions based on mathematical relationships that apply at lower levels.
Traditional use (of Exploitation of natural resources by indigenous users, or non-indigenous residents using traditional
natural resources) methods. Local use refers to exploitation by local residents.
Urban sprawl The decentralization of the urban core through the unlimited outward extension of dispersed
development beyond the urban fringe, where low density residential and commercial development
exacerbates fragmentation of powers over land use.
Urbanization An increase in the proportion of the population living in urban areas.
Vulnerability An intrinsic feature of people at risk. It is a function of exposure, sensitivity to impacts of the specific
unit exposed (such as a watershed, island, household, village, city or country), and the ability or
inability to cope or adapt. It is multi-dimensional, multidisciplinary, multisectoral and dynamic. The
exposure is to hazards such as drought, conflict or extreme price fluctuations, and also to underly-
ing socio-economic, institutional and environmental conditions.
Wastewater treat- Any of the mechanical, biological or chemical processes used to modify the quality of wastewater
ment in order to reduce pollution levels.
Water quality The chemical, physical and biological characteristics of water, usually in respect to its suitability for
a particular purpose.
Water scarcity Occurs when annual water supplies drop below 1 000 m
3
per person, or when more than 40 per
cent of available water is used.
Water stress Occurs when low water supplies limit food production and economic development, and affect hu-
man health. An area is experiencing water stress when annual water supplies drop below 1 700
m
3
per person.
Wetland Area of marsh, fen, peatland, bog or water, whether natural or artificial, permanent or temporary,
with water that is static or flowing, fresh, brackish or salt, including areas of marine water to a
depth at low tide that does not exceed 6 metres.
72 VITAL GEO GRAPHICS