Climate change has increased the average water temperature of rivers and lakes and reduced the length of ice seasons. These changes, together with the increase in river flows in winter and their reduction in summer, have a major impact on water quality and freshwater ecosystems. Some of the changes triggered by climate change exacerbate other pressures on aquatic habitats, including pollution. For example, a lower river flow, due to less rainfall, results in a higher concentration of pollutants, as there is less dilution of pollution.
Some studies show that the planet's ponds harbour more biodiversity than rivers and lakes, as well as a greater number of rare and threatened species. Many aquatic plants and animals are totally dependent on these habitats to survive or reproduce. These bodies of water also provide food and refuge for numerous terrestrial species.
“There are millions of ponds in Europe, rich in biodiversity and supporting a wide range of rare and endangered plants and animals. They offer a range of ecosystem services, and this is particularly important in the context of climate change. These waterbodies are also important to European culture and history, and provide one of the closest links between people and wildlife.”
https://www.europeanponds.org/wp-content/uploads/2014/12/EPCN-manifesto_english.pdf