Rural depopulation to have biodiversity impacts
December 1, 2008
Urbanization — and accompanying rural abandonment — may have profound implications for global biodiversity and therefore should factor into conservation planning, argue researchers writing in the December issue of Tropical Conservation Science.
Analyzing the impact of population growth and urbanization on rural depopulation rates in 25 countries, Aerin Jacob and colleagues project a continuing decline in rural population density. They argue that this process will lead to ecological homogenization as a dominant habitat (secondary forest or savanna) replaces a mosaic of human-maintained landscapes, resulting in declines in biodiversity at the local scale.
Jacob, a biologist at McGill University, says she and her colleagues first noticed these trends during fieldwork in protected areas in Uganda and rural parts of Spain and Mexico.
"We saw that as people moved out of rural or newly protected areas and into cities, there was a sharp decline in human-caused disturbances like fires, grazing livestock and cutting fuelwood," she told mongabay.com, publisher of Tropical Conservation Science. "This pushed the landscape to change from a mosaic of diverse habitats towards one dominant habitat type, in this case to forest."
"We need to understand the social, biological and economic reasons behind rural depopulation if we want to conserve biodiversity and help rural people deal with declining populations," she continued. "Globally, the situation is complex. Rural depopulation and the resulting environmental changes will not happen everywhere. Nor does a decrease in habitat diversity necessarily imply conservation losses."
"No one knows the fate of these abandoned lands–sometimes they degrade further, sometimes they are left to recover to their previous state, and sometimes they are transformed into industrial plantations for crops like tea or palm oil. But the fact that we have observed these trends in both temperate and tropical areas, together with our documentation of increasing urbanization and declining fertility rates around the world, mean that the wheels have likely been set in motion for rural depopulation to occur in many other regions.
Jacon and her co-authors concluding by suggesting research programs that could help policy makers prepare to effectively manage depopulated rural areas.
"There’s a big opportunity for new research to figure out when and where rural depopulation will occur and what will happen to abandoned lands."
Jacob, A. L., Vaccaro, I., Sengupta, R., Hartter, J. and Chapman, C. A. 2008. Integrating landscapes that have experienced rural depopulation and ecological homogenization into tropical conservation planning. Tropical Conservation Science Vol.1 (4):307-320.