Question

Species area curves are used to predict extinction risks under climate change. What assumptions are made when using these curves? How realistic are the prediction?

Answer 1

The most widely used method using species area curves is the indirect method. It measures the rates of extinction by reversing the species area curve, extrapolating it backwards. It takes into account smaller areas owing to loss of species. However, the estimates of extinction rates are found to be much higher than that of the predicted values. This gives rise to extinction debt referring to species which are commmited to extinction owing to climate change and habitat loss but they did not get extinct owing to the non equilibrium period. Moreover, the last species to be extinct should always be considered in a greater and much larger area and not the first individual. Also, habitat loss and population dynamics should both be considered while predicting extinction but they are rarely coupled. Also, shifts of the climate do not translate to extinction often.