Threats to River Habitats and Associated Plants and Animals

Abstract

Man has, for millennia, exploited rivers to utilise their power and resources, and damaged them due to other activities within their catchments. Physical character combines with the quality and quantity of water to shape environmental quality. Threats to rivers vary across the world, with some of the biggest being to rivers that were hitherto pristine whilst in other parts of the world rivers were being almost destroyed (e.g. Industrial Revolution in Europe). Across the world, the push to grow more food results in rivers being canalised and floodplains drained. Still, therefore, most threats come from the ever-increasing human population that needs food and safe drinking water.

The fate of river wildlife, everywhere, is still shaped by a combination of natural and anthropogenic factors. Many rivers have already had their physical character drastically changed so that the natural wildlife they could be expected to support is greatly diminished. Such changes can be as a result of channelisation, water transfer and the building of dams to control flow. In Europe, future threats should be reduced, or even reversed, as a result of implementing the Water Framework Directive. Worldwide, however, pressure for catchment impoundments for water supply and hydro-generation remain immense with rivers in tropical rainforest still highly threatened. Increasing demands for ‘green’ energy are wise, yet this puts rivers at risk of severe degradation.

The sorry story of the rest of the world ‘catching-up’ Europe on destroying the physical character of rivers is being repeated by water quality degradation and threats. Again, we see huge investments in some parts of the world cleaning up pollution problems, whilst chronic pollution still occurs, threatening the few pristine rivers we have left. In common with many terrestrial habitats, river wildlife is also greatly threatened the world over by species of plant and animal that have been introduced from other parts of the world (aliens), often causing complete wipe-out of native species.