Fresh Water (Rivers & Lakes): Try Living Without It!
The decline of freshwater ecosystems
n a world in which it seems that nearly every natural ecosystem is under stress, freshwater ecosystems – the diverse communities found in lakes, rivers, and wetlands – may be the most endangered of all. Some 34 percent of fish species, mostly from fresh water, are threatened with extinction, according to the latest tally of the World Conservation Union (IUCN), which tracks threats to the world’s biodiversity [1]. Freshwater ecosystems have lost a greater proportion of their species and habitat than ecosystems on land or in the oceans; in addition, they are probably in greater danger of further losses from dams, pollution, overfishing, and other threats [2].
In extent, freshwater ecosystems are quite limited, covering only about 1 percent of the Earth’s surface. Yet, they are highly diverse and contain a disproportionately large number of the world’s species. The Amazon River, for instance, is home to more than 3,000 fish species. Lake Victoria in Africa has – or had before recent depredations – as many as 350 species of a single family of fish (cichlids) [3]. The Mississippi River in North America contains almost 300 freshwater mussel species [4]. In all, more than 40 percent of the world’s fish species [5] and some 12 percent of animal species in general [6] reside in freshwater habitats, with many of these species restricted to extremely small areas and therefore quite vulnerable to disturbance
