Habitat destruction is a major threat to species with habitat loss impacting 86% of threatened birds, 86% of threatened mammals and 88% of threatened amphibians. The human transformation of the earth's land area, with forests being destructively felled at 14.6 million hectares each year (30 hectares a minute) is relentless, with the highest rates of loss being in Africa, Asia and South America. Habitat destruction is also caused by the use of increasing amounts of land area for agriculture to feed the ever growing human population and the spread of urbanisation on a vast scale. Habitats under assault are:
Forest and grassland
Only 8% of the world's forests are under protection and yet the vast majority of mammal species and 75% of bird species live in forests. Endangered species such as the gorilla, orang-utan and chimpanzee depend on the forest for their survival. Forests are legally and illegally cleared at such a voracious rate (14.6 million hectares per annum) that the world's forests could have disappeared well before the end of this century! We have already lost half of the world's forests in just 50 years, and the rate of loss is accelerating!
Grasslands such as the African savannah and American grass and shrublands, home to such endangered or rare species as the African elephant, rhinos, leopards, tigers, bears, lions and zebra and North American bison are rapidly disappearing under the plough for agriculture.
Marine and coastal habitats
In coastal waters there are development pressures on coastal habitats, ie through tourism and destructive fishing methods both of which are damaging or destroying the coral reef habitat. As a result the world's oceans are being quite simply over-fished with fish species declining rapidly. Thousands of miles of fishing nets are literally emptying the oceans beyond a sustainable level. Coral reefs are being damaged by dynamite, cyanide, ship anchorage and ocean floor fishing nets. For over a century, uncontrolled pollution has been entering the oceans in the form of raw sewage, agricultural and industrial chemicals running off the land and massive spillages of oils and chemicals from ships, while, on the surface, busy shipping lanes cause havoc for large cetaceans. The Indian and Pacific oceans are seeing the highest numbers of threatened marine mammals including dolphins, porpoises, whales, seals and seahorses. The Atlantic and the Pacific have large numbers of threatened seabirds and are also home to critically endangered mammals including the Northwest Pacific grey whale and the North Atlantic right whale.
These are represented by the world's wetlands, rivers and lakes in and upon which mammals, fish and bird species depend. Wetlands are being drained for agriculture and urban development, rivers are being dammed and lakes are drying up. Freshwater is under intense pressure for commercial and domestic use.
In a rare number of cases species that have officially become extinct in the wild, have been reintroduced into their original habitat. However, this can only hope to be successful if sufficient habitat remains to support them, which is often not the case.