Although life on Earth extends to the most remote and inhospitable places, most living creatures are adapted to the “best” environmental conditions, which include factors such as permanent availability of water, oxygen and light or food and stable chemical conditions with salinity below 1 per one thousand in inland waters. Hypersaline environments or widely varying conditions, such as tidal flats, are very stressful environments for most species and only a few specially-adapted organisms can live in them.
Climate change and water pollution generate stress on ecosystems and this results in impoverishment. It should be borne in mind that stress is due not only to the nature of the change, but also to its speed and intensity. Drastic changes may hinder the replacement of species by others and prevent them from adapting to ecosystems, so increasing the risk of desertification.