It is discouraging, though not surprising, that for species after species it is those that live all or part of their lives in freshwater that are most vulnerable to human intervention. Many freshwater fish, amphibians, mussels, crayfish and dragonflies are threatened or endangered, while many others are already extinct. The reasons that freshwater species are so vulnerable to human intervention are various. Some are obvious. Habitat destruction, invasive alien species, overexploitation and pollution are powerful threats to the biodiversity of freshwater ecosystems.
People often tend to live, work, consume and release their wastes near inland water.
They dam, divert, channel, impound, reclaim and regulate rivers and lakes for a variety of purposes such as energy production, industry and agriculture until they bear little or no resemblance to the original ecosystems within which the life forms evolved. The life forms inhabiting these confined ecosystems often have nowhere to go, and the result is their elimination. Even raindrops may contain traces of potent, man-made chemicals that can have an impact on biota and humans thousands of miles from the sources of pollution. If we are to understand and try to address the causes of biodiversity loss we have to recognize that these biophysical stresses are a result of certain human values, decisions and socio-economic systems. For example, growing international trade and other pressures associated with globalization are breaking down barriers of every kind.