Sunday, January 18, 2009

Humans driving rapid change in hunted/harvested species

In the Proceedings of the National Academy of Sciences this month it was reported that a review of studies of species used by humans for food showed rapid changes in these species size and growth rates. The study shows:
"that average phenotypic changes in 40 human-harvested systems are much more rapid than changes reported in studies examining not only natural (n = 20 systems) but also other human-driven (n = 25 systems) perturbations in the wild, outpacing them by >300% and 50%, respectively. Accordingly, harvested organisms show some of the most abrupt trait changes ever observed in wild populations, providing a new appreciation for how fast phenotypes are capable of changing. These changes, which include average declines of almost 20% in size-related traits and shifts in life history traits of nearly 25%, are most rapid in commercially exploited systems and, thus, have profound conservation and economic implications."

Human predators outpace other agents of trait change in the wild

by Chris T. Darimont, Stephanie M. Carlsonc, Michael T. Kinnisond, Paul C. Paquete, Thomas E. Reimchena and Christopher C. Wilmers.