Many ecosystems depend upon groundwater for some or all of their water supply. Some ecosystems, such as springs and certain rivers, lakes and wetlands depend on the actual discharge of groundwater at the surface. Other ecosystems, for example certain forests and riparian areas, depend upon the water table being relatively near the surface. Aquifer and subterranean ecosystems rely on the flow of groundwater below the surface.

There is often uncertainty about the reaction of individual species to hydrological change and species interdependence within a groundwater- dependent ecosystem. Moreover, the way that groundwater discharges into, and interacts with, the surface environment can be critical to aquatic life. Whilst certain irreversible changes can occur in relatively short periods, some species are well adapted to survive hydrologic extremes, and those naturally exposed to variations in groundwater behaviour are more resilient.

Conservation of biodiversity that depends on groundwater requires developing strategies that allow for the use of groundwater in a way compatible with the persistence of these species and ecosystems. Development of these strategies must be based on an understanding of

• Species and ecosystems that depend on groundwater
• How biodiversity depends on groundwater
• The extent, source and movement of groundwater
• How alterations in the amount of quality of groundwater affect groundwater-dependent biodiveristy