Human activities cause species decline (SEPT)
Sep 6, 2001 for National Threatened Species Day – 7 September
Humans are now bringing about more extinctions than any other single factor since the end of the dinosaurs, according to Sustainable Population Australia (SPA).
Species become extinct from a range of human activities including the introduction of alien species, habitat destruction or fragmentation, and from hunting. In Australia, extensive land clearing and grassland modification have been major drivers of species extinctions.
National President of SPA, Dr Harry Cohen, says it is inevitable that as human populations grow, natural habitats are disturbed or destroyed to make way for housing, roads, infrastructure or farming.
“Farming is damaging because fertilisers encourage introduced pasture species at the expense of native grasses and the animals that feed on them,” he says. “Fertilisers and pesticides leaking into waterways often lead to the spread of blue-green algae which in turn causes eutrophication and death of fish species.
“The list of endangered species in Australia includes 10 species of fish, 12 frogs, 13 reptiles, 32 birds, 33 mammals and 209 plants,” says Dr Cohen. “And let us not forget the insects which make up 70 per cent of our biodiversity. Many are disappearing before they have even been identified.”
Six billion humans on the earth now consume about 40 per cent of the planet’ s annual biological productivity. Scientists now estimate that the rate of world-wide extinctions has increased from a background rate of 1-10 species a year to at least 1000 annually.
The eminent biologist, Edward Wilson, stated recently that “virtually all students of the extinction process agree that biological diversity is in the midst of its sixth great crisis, this! time precipitated entirely by man.” The previous crisis was the extinction of the dinosaurs, thought to have been caused by global cooling following impact by a large meteorite.
“If we are to reverse this acceleration in the loss of species, we must remove threats such as vegetation clearance, feral animals and degradation of water systems,” says Dr Cohen. “Yet clearing continues unabated in Queensland and to a lesser extent in New South Wales and other states.
“As well as specific programs to remove feral animals, we must deal with the reasons that lead to habitat loss or fragmentation, namely population growth. If we are serious about species decline, we must see that population growth ends as soon as practicable, both in this country and globally.”
Dr Harry Cohen, Ph(h): 08 9386 5268 Ph(mobile): 0407 426 987 E:firstname.lastname@example.org
Jenny Goldie (SPA National Director) Ph: 02 6235 5488 E: email@example.com