The sustainable management of forests is one of the main issues at the Oct 18-29 UN biodiversity summit that is being held here under the shadow of a failed promise - in 2002 all nations agreed to halt biodiversity loss by 2010, but have failed to do so. India is also a participant at the summit.
Tim Christoferson of the secretariat for the UN Convention on Biological Diversity (CBD) said that even in many tropical forests where trees are standing, the animals in them have been killed for food. "This has a huge effect, because up to 75 percent of tropical plants depend on animals to disperse their seeds," he pointed out.
"It's also vital for human nutrition. In central Africa, up to 80 percent of households depend on forest animals for their animal protein." And the forests have fewer animals.
But international agreement on sustainable management of forests continues to be stuck over the issues of how much rich countries will pay poor countries for it, and over who will measure the success of any effort to arrest deforestation.
There is another bone of contention - global efforts to combat climate change have also focussed on forests, since deforestation accounts for about 20 percent of the excess greenhouse gases which are warming up the planet. The question here is how to safeguard biodiversity while arresting deforestation and who will do it. Some countries want the CBD to play an active role, while others want that debate to be kept within the UN Framework Convention on Climate Change.
While the squabbling continues, experts say there are ways to slow the continuing biodiversity loss. Henrique Miguel Pereira and Paul Leadley led a 23-member team of scientists from nine countries to look at recent studies, and found "universal agreement across the studies that fundamental changes are needed in society to avoid high risk of extinctions, declining populations in many species, and large scale shifts in species distributions in the future".
Leadley, of the University Paris-Sud, said: "There is no question that business-as-usual development pathways will lead to catastrophic biodiversity loss. Even optimistic scenarios for this century consistently predict extinctions and shrinking populations of many species." He described the UN target of stopping biodiversity loss by 2020 as something that "sounds good, but sadly isn't realistic".
But the scientists were hopeful that slowing climate change and deforestation can go hand-in-hand to reduce biodiversity loss thanks to "significant opportunities to intervene through better policies, such as those aimed at mitigating climate change without massive conversion of forests to biofuel plantations", according to Leadley.
"But action must be taken quickly, as the study indicates the window of opportunity is closing rapidly, as differences in policy action taken now could either lead to an increase in global forest cover of about 15 percent in the best case or losses of more than 10 percent in the worst case by 2030."
The authors say the creation of an Intergovernmental Panel on Climate Change (IPCC)-like mechanism for biodiversity (to be called the Intergovernmental Platform on Biodiversity and Ecosystem Services -- IPBES) is "extremely important" for achieving commonly-agreed definitions and indicators for biodiversity and to inform decision making.
They note that changes in species distributions and population sizes should receive more attention because they are probably more critical to human well-being and better short-term indicators of the pressures of humans on ecosystems. For example the continuing overall decline in populations of large-bodied fish species due to over-fishing, the poleward migration of marine species at a rate of more than 40 km per decade due to climate change, and the 10 to 20 percent decline in the abundance of terrestrial species by mid-century primarily was due to land-use change.