Decreasing animals

A decreasing population is a decline in population size that can be caused by sudden adverse events such as outbursts of infectious disease, habitat destruction, including intensive agriculture; the use of pesticides; urbanization, and industrialization; introduced species; climate change; human activities, and war or by long-term trends, for example, low reproductive rate and high mortality rates. Most commonly, the declines involve reductions in abundance, though in some cases entire species are going extinct.