Study on natural and human impacts on red-crowned crane habitat in the Yellow River Delta Natural Reserve

This study aims to assess the relative importance of natural and human influences on the change of the red-crowned crane habitat in the Yellow River Natural Reserve, East China using remote sensing and geographic information system (GIS). Two Landsat images were used to detect the change in potential crane habitat, from which suitable crane habitat was determined by excluding behaviorally and physically fragmented areas. It is found that suitable habitat decreased by 5,105 ha in spite of the increase of 4,747 ha in potential habitat during 1992-2008. Natural and anthropogenic forces exerted an almost equal influence on habitat change. Retrogressive succession accounts for 41.9% of the change arising from natural factors. By comparison, land use, the predominant anthropogenic factor, is responsible for 83.6% of the total human-induced change. Although the Yellow River flow has been diverted to the degraded wetlands since 2002, such an effort has not restored the habitat quality to its 1992 level due to physical fragmentation and intensified human disturbance. Thus, complementary restoration efforts should aim at implementing commensurate measures to rationalize the spatial allocation of reed marshes and water, and curbing anthropogenic influences inside the Reserve.