Remotely sensed nighttime lights reveal increasing human activities in protected areas of China mainland

Due to China's remarkable socioeconomic development, more and more protected areas have been affected by human activities which resulted in habitat loss and biodiversity decline. Timely and accurate quantification of human activity dynamics in protected areas will allow more informed and effective measures to be taken for biodiversity conservation. However, effective ways of quantifying human activities in protected areas are still lacking. In this letter, we employed the Defense Meteorological Satellite Program's Operational Linescan System (DMSP-OLS) nighttime light data as an effective proxy for evaluating and monitoring spatiotemporal dynamics of human activities in protected areas of China mainland. The results show that China's protected areas have experienced a remarkable growth of nighttime lights from 1992 to 2012. Nighttime lights were mainly located in cultivated land and forest. Special attentions should be paid to Yangzie, where two critically endangered species were confirmed to be threatened by prosperous human activities. Our findings from nighttime lights can provide useful information about where prior attentions are required for policy-making on the conservation of protected areas.