Impacts of rapid urbanization on ecosystem services along urban-rural gradients: a case study of the Guangzhou-Foshan Metropolitan Area, South China

Based on land-use data collected every five years from 1990 to 2010, we quantified land-use dynamics and resultant effects on the ecosystem services along urban-rural gradients of the Guangzhou-Foshan Metropolitan Area, South China. The urban-rural gradients were set around the urban core cohesion zone with a 10-km-wide buffer zone and the value of each ecosystem service was calculated using a well-established benefit transfer method. The areas of construction land, water body and orchard expanded, while cropland, forestland and unused land contracted. The total value of ecosystem services decreased by US$ 200.33 million (or 4.3%) from 1990 to2010. Along the urbanrural gradients, the average value supplied by cropland, orchard and water body generally demonstrated a 'first-rise-then-fall' trend, while forestland and construction land presented an ever-increasing trend. For individual ecosystem services, raw material, gas regulation, climate regulation, soil formation and retention, biodiversity protection, recreation and culture increased steadily along the urban-rural gradients, while food production showed a fluctuating 'first-rise-then-fall' trend; water conservation and waste treatment increased fromthe core cohesion zone to the third concentric ring, and then had a sudden surge in the seventh concentric ring in both 2005 and 2010.