The vast majority of extinctions in the Brazilian Amazon is yet to come, predicts the study report which appeared in the journal Science.
In recent years, cutting down the rain forest in Brazil fell to a record low, and has a little more than half of these areas have a particular protection status. But the consequences of the loss of habitat living beings not yet fully apparent.
"Cutting down trees does not kill birds directly - write ecologist Robert Yuers from Imperial College London (UK) and his colleagues. - This will take a lot of time. Now all of them slipping into the environment, which still remains. You will then begin a gradual increase in mortality ».
Previous models of how deforestation affects biodiversity, it is understood that the forest destroyed in one fell swoop. In reality it is not so. Cutting usually occurs unevenly, and the number of species heading for extinction, changes over time - is growing.
Thus increasing debt and a kind of man to nature (extinction debt) - or better to say, the probability of extinction of the species whose habitat area destroyed. On the basis of these considerations, Mr. Yuers with the help of fellow mathematicians Daniel Reiman and Oliver Uirna invented a formula that relates the terms of species with a share of the lost habitat.
Model tested on vertebrate animals that depend on tropical forests, giving them food and shelter. They took data on deforestation for the 1970-2008 years, it turned out that 80-90% of extinctions is still ahead. Brazil has yet to give an old woman with a scythe in an average of two species of mammals, five birds and one species of amphibians with each destroyed plot of 2500 square kilometers.
Then scientists with four scenarios looked 40 years into the future: either everything will remain as it is (that is, to control the lumberjacks will continue through the fingers), or some kind of control still appears, either in 2020 the authorities will achieve the reduction of deforestation 80% or 2020 Deforestation of the will be completely stopped. In the most likely scenario - the second - the local ecosystem will lose an average of 12 species, 19 more will be on the verge of extinction. In the worst case would be destroyed almost all the local animals.