Effects of land-use change on eco-environmental quality in Hainan Island, China

Hainan Island is the largest tropical island in China, which is vulnerable to intensifying human activities, such as deforestation and urbanization affecting the quality of the eco-environment on regional scale. To quantify the temporal and spatial changes of the environment, multispectral Landsat data with 30-m spatial resolution was used to establish an Eco-environmental Quality Index (EQI) model for evaluating the ecological status of Hainan Island from 1990 to 2015. According to the EQI value, the study area was divided into different regions marked by five eco-environmental quality levels: excellent, good, normal, poor, and very poor. Finally, temporal and spatial analysis was incorporated into the eco-environmental quality assessment, and the effect of land-use changes on eco-environmental quality was discussed. The results indicated that the overall eco-environmental quality of Hainan Island belonged to the good class but with obvious spatial variation: the eco-environmental quality was excellent in the central mountainous area, good in the flat plane surrounding the mountains, whereas the quality was normal in the coastal areas. From a temporal perspective, the eco-environmental quality of Hainan Island has reduced slightly from 1990 to 2015, while the regions gaining better quality grades have exceeded those becoming worse. Land-use changes dominated eco-environmental quality variations during the study period in Hainan Island: areas of poor eco-environmental quality have expanded in residential regions and eco-environmental quality of rubber plantations has increased since its expanding area has been converted from land of worse eco-environmental quality grades. The EQI results are expected to provide a quantitative foundation for planning sustainable development and the rational use of resources in Hainan Island.