Effects of drought on freshwater ecosystem services in poverty-stricken mountain areas

Abstract

As a result of global temperature warming, the frequency and intensity of global extreme climate events have increased, which has a large impact on the structure, composition, and function of regional ecosystems, thereby weakening the supply capacity of ecosystem services and the sustainable development of the social economy. The Guizhou Province in China is characterized by frequent droughts, fragile mountain ecosystems and poverty. We used Guizhou Province as an example and analyzed the impacts of drought on freshwater ecosystem services. The results showed that the water yield and soil retention in Guizhou decreased due to the influence of annual and seasonal droughts. Annual droughts led to an increase in nutrient retention whereas seasonal droughts caused an increase or decrease in nutrient retention in the study area. The water yield and nutrient retention exhibited decreasing and increasing trends respectively with an increase in the degree of drought. However, changes in the soil retention in Guizhou had a week correlation with the degree of drought. There was a synergistic relationship between water yield and soil retention under the impacts of annual and seasonal droughts in Guizhou. Tradeoffs between water yield and nutrient retention, as well as between soil retention and nutrient retention, existed under the influence of annual drought. Nevertheless, tradeoffs or synergies between water yield and nutrient retention, as well as between soil retention and nutrient retention, were found under the influences of seasonal droughts. The results of this study provide science-based information for alleviating the adverse effects of drought on freshwater ecosystem services and contribute to the scientific management of freshwater ecosystem services.