The simultaneous effect of habitat fragmentation, overexploitation, and climate warming could accelerate the decline of populations and substantially increase their risk of extinction, a study published in the Proceedings of the Royal Society B has warned.
Using experimental microcosm populations of rotifers (a type of zooplankton), the study found that individually each of these threats caused significant population declines. The study also found that the rate of declines was much accelerated when populations were exposed to more than one threat. These results indicate that multiple interacting threats are capable of causing rapid population extinction, and that all threats should be simultaneously reduced, if their synergies are to be avoided and if the current rate of species loss is to be reversed.
Many scientific efforts have been made to link the decline of wild marine and terrestrial populations with human activities such as habitat fragmentation, overexploitation and global warming. "Establishing the link between the loss of biodiversity and human-related threats is crucial to develop policies aimed at mitigating such threats", says Camilo Mora at Dalhousie University, leading author of the paper. "Unfortunately, in many cases several threats are operating simultaneously making it difficult to isolate their individual and combined effects through field observations,"Mora adds.
This new study used an experimental approach that has been broadly used in ecology to shed light into complex ecological processes. In this approach, populations of rotifers were maintained at equilibrium under laboratory conditions and then exposed to the simulated effect of exploitation, habitat loss and warming. Changes in population size were then quantified and compared to the changes occurred among populations that were not impacted.
"Our experiment clearly shows that exploitation, habitat loss ad warming are equally capable of causing
'"/>
Contact: Camilo Mora
cmora@dal.ca
619-618-0319
Dalhousie University
7-Feb-2007