Alongside many water issues has been a gradual degradation and loss of habitats and biodiversity, particularly in aquatic ecosystems. In an ecosystem, everything is related. Damage to a single species or a small habitat has repercussions elsewhere in the food chain. In the name of flood defence, rivers have been straightened, dredged, lined with concrete and cleared of vegetation. This has dramatically disrupted the ecosystem, removing vital habitats for plants, animals and even micro-organisms. Beyond the banks of watercourses and wetlands are deforested landscapes drained for agriculture or urbanisation. Important habitats are lost, as well as the networks of passageways between them.