Glossaire de A à Z

The term ‘habitat’ refers to an inseparable complex comprising: - fauna, including species that carry out all or part of their various life activities within the area in question; - vegetation (herbaceous, shrubby and arboreal); - a site-specific environment (climatic conditions, soils and parent material, and their physico-chemical properties). A habitat is not limited to vegetation alone. However, due to its integrative nature (synthesising the environmental conditions and functioning of the system), vegetation is considered a good indicator and helps to define the habitat. (source: Rameau et al., 1998).

Environment defined by specific abiotic and biotic factors in which a species lives at any stage of its life cycle. A natural habitat is distinguished by geographic, abiotic and biotic entirely natural or semi-natural.

Endangered habitat or having a reduced range or constituting a remarkable example of characteristics specific to one or more of the biogeographical areas listed in Annex 1 of the habitats directive and for which some special areas of conservation (SACs) must be designated.

Qualifies activities related to fishing in all its forms, professional or recreational, in freshwater or marine areas.

Toxic, persistent and bioaccumulative priority substance whose discharge and loss into the environment should be stopped.

Flow, or relatively high level of water, and also the highest of the year, as measured by the water level or flow. During a period of high flow, the river takes its floodplain.

Homogeneous area in terms of geology, topography and climate. This is one of the main criteria used in typology and delimitation of surface water bodies. Continental France can be divided into 21 major hydro-ecological areas.

Collecting area extending from an outlet or a set of outlets and with a border inside which are gathered the waters flowing underground to that outlet. The limit is the groundwater watershed.

Development potential of electricity generation processes in hydropower plants.

Machine capable of producing mechanical energy from water and then converting it into electricity. The turbine is the main component of a hydropower plant.

Groundwater science, included in the Earth sciences. Hydrogeology combines knowledge of the geological and hydrological conditions and physical laws governing the origin, presence, movements and properties of groundwater, as well as the application of this knowledge to human actions on groundwater, including their prospection, their capture and their protection.

Part of physical geography that deals with oceans, seas, lakes and streams. Hydrography also designates all the rivers and lakes in a territory.

All physical and biological phenomena (water, erosion, etc), and their interactions within the river system or hydrosystem. Thus the great diversity of plant and animal communities (Living communities) is expressed only by river dynamics (alternating low and high-flow levels, deposits and erosion, etc). These phenomena are influenced by the different uses and can contribute to meet the latter.