Algemeen

Built on a fragile balance of predators and prey, Australia's various ecosystems are highly susceptible to change. When human intervention consistently alters an ecosystem, this balance can be upset, seriously threatening the biodiversity. While all species are important to an ecosystem, 'keystone' species are particularly vital. These are often top predators such as crocodiles, because of the role they play in controlling prey. The southern cassowary, however, is also a keystone species as it spreads the seeds of as many as 238 species of plants in northern Queensland. "Importantly, research clearly shows that biodiversity contributes significantly to our survival, well-being and enjoyment of life, so when we lose species at the rates that we're currently witnessing, we should be gravely concerned," says Dr Euan Ritchie an ecologist at Deakin University in Melbourne. "Losing any one species is a tragedy, but what is even more concerning is the loss of a species' ecological role following its extinction," says Euan. "If we were to lose dingoes, as an example, we also lose their ability to control pest species such as foxes and cats, and overabundant herbivores, [like] pigs, goats and kangaroos, which has widespread and often negative impacts across the whole system."

All around him, even in a place as beautiful as the Little Qualicum River estuary, his office for 30 years as a biologist for the Canadian Wildlife Service, he sees the unravelling of "the web of life." "It's happening very quickly," he says. Registered Professional Biologist Neil Dawe has written over 80 papers on birds, ecology and the environment. He received Environment Canada's Regional Citation of Excellence Award for his work in co-founding and co-chairing the Brant Wildlife Festival. He received the Outstanding Service Award from the Federation of B.C. Naturalists and the Ian McTaggart-Cowan Award of Excellence in Biology from the Association of Professional Biologists of B.C. In 2006, he retired from the Canadian Wildlife Service, Environment Canada, after 31 years of managing National Wildlife Areas and Migratory Bird Sanctuaries on Vancouver Island. He is President of the Qualicum Institute: www.qualicuminstitute.ca.

Humans are modifying the global landscape at an unprecedented scale and pace. As a result, species are declining and going extinct at an alarming rate. I examined patterns of species’ declines in three different groups in relation to a number of anthropogenic variables. I found high losses of Canadian imperiled bird, mammal, amphibian and reptile species in regions with high proportions of agricultural land cover. However, losses of imperiled species are significantly more strongly related to the proportion of the region treated with agricultural pesticides. This is consistent with the hypothesis that agricultural pesticide use, or something strongly collinear with it (perhaps intensive agriculture more generally), has contributed significantly to the decline of imperiled species.

The State of Nature, a report published in May by a coalition of environmental charities, found that more than half our wildlife species are in decline. "We are heading for Armageddon in terms of nature. We are faced with a nightmare of no nature in large parts of southern England," says Mark Cocker, author of Birds and People, a monumental new account of the role birds play in human life. "The filigree of our lives, the things that make it fantastic – silver-washed fritillaries, nightingales, dunlin, water voles chomping away at the edge of the pool – are disappearing. We are faced with the most appalling loss." Cocker's passion echoes a rollickingly fierce speech to the Welsh assembly earlier this summer by Iolo Williams, the RSPB officer turned Springwatch presenter, which is still being passed around and debated among naturalists. In it, Williams recalled his childhood by the Vyrnwy river, currently imperilled by proposals for pylons and infrastructure to service vast wind farms. The Mid Wales countryside may still appear glorious but, according to Williams, it is bereft: water voles, trout, curlew and cuckoos are gone; so, too, are insects and hay meadows (Wales has lost 99% of its hay meadows since the second world war). On the moors, alien conifers have been planted. "It's like going and looking at war graves. Every single tree is a death-knell, a nail in the coffin of that moor," said Williams. "We really are on the brink of disaster."