Freshwater wildlife threatened by pollution, dams, intensive farming

The threats to flora and fauna are increasingly diverse and complex. A quarter (24%) of freshwater wildlife, including crustaceans, fish and insects, face a ""high risk of extinction'' due to ""considerable pressures'' such as pollution, dams or intensive farming that are affecting their habitat, a study published in the scientific journal Nature concluded. Freshwater, including rivers, lakes and wetlands, is home to more than 10% of known species, including about a third of vertebrates and half of fish, despite covering less than 1% of the Earth's surface. This biodiversity is both very rich and very fragile and represents a major stake for the livelihoods and economic development of ""billions of people around the world'', as well as a factor in mitigating the effects of climate change, the study authors stressed. Of the 23,496 species studied, the threat is particularly significant for decapods (shrimps, crayfish, crabs, etc.), of which 30% are at risk of extinction, but freshwater fish, tetrapods (frogs, salamanders, reptiles but also birds and mammals) and odonates (dragonflies) are also at risk, with 26%, 23% and 16% of their species at risk of extinction, respectively. A total of 89 freshwater species have already been confirmed as extinct since 1500, and another 178 are suspected of being extinct. "There is an urgent need to act quickly if we do not want other species to decline or disappear in their turn," the study authors warned, calling for "changes in management practices" of freshwaters that take greater account of biodiversity. These figures may be underestimates because for a certain number (23%) of these species, information remains insufficient, the study, which was based on data and methodology from the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, states. The threats are diverse: 54% of threatened species are affected by pollution, 39% by dams and water extraction, 37% by land-use change and the associated effects of agriculture, and 28% by invasive species and diseases. Almost a fifth of threatened freshwater species also suffer from climate change and severe weather events. The majority of threatened species (84%) are affected by more than one threat. This decline is "largely continuing under the radar," while the condition of wetlands, 35% of which have already disappeared between 1970 and 2015, continues to deteriorate. Of those that remain, 65% face moderate to high threats, and 37% of rivers over 1,000 kilometers have their natural courses obstructed, the study highlights.