The Hydrological Response to Climate Variability and Hurricane -Induced Forest Change in a Coastal Experimental Watershed of China

Rainforest plays an important role in water cycle in a tropical watershed. Climate change and forest disturbances such as logging, fire, insect infestation, and hurricane may produce significant impact on dry/wet season flows and associated ecological functions. The hydrological impact of logging and fire or climate change has been well studied, while the impact of hurricane-related forest changes on water has been less investigated. In this study, we examined the hydrological impact of climate variability and hurricane-induced forest changes in Jianfengling catchment based on a 15-year experimental study. Jianfengling rainforest is a typical tropical rainforest ecosystem with limited anthropogenic disturbances in the Hainan Island of China, where hurricanes are the dominant forest disturbances. By a combined use of experimental and remote sensing data, we identified a decreasing trend in NDVI and EVI of the study watershed from 1990 to 2005 due to forest loss by hurricanes. The results showed that forest loss due to hurricanes led to an increase in both annual water yield and wet season water yield while climate variability had a negative effect on them. The lagged response of dry season water yield to forest loss by hurricanes was also detected. The offsetting effects of climate variability and forest loss by hurricanes led to a stable water yield in this tropical rainforests over the study period. These findings are of great importance for future water resources and forest mangement in tropical coastal watersheds under climate change.