Spatial patterns and drivers of forest ecological functions in a typical soil-rock mountain area of northern China along an elevational gradient

Abstract

Because of the gradient effect of various environmental factors, mountain areas provide favorable conditions for studying the responses of vegetation to global climate change. As a crucial part of the soil-rock mountain area in northern China, the Beijing mountain area is an important ecological barrier to the capital of China. We investigated the main ecological functions of the forest ecosystem in a typical soil-rock mountain area. Taking elevation and slope direction as the spatial quantity, the spatial heterogeneity of the main ecological functions of the forest ecosystem at elevations from 150 to 1,050m were analyzed. The five functions were mostly intercorrelated; the highest correlation was found between water yield and biodiversity. The most important ecological element was soil moisture, and the high content of soil gravel limited water availability. Against the background of climate warming and drying in North China, water yield and diversity may continue to decreased in the near future, further enhancing ecological pressure. Therefore, we suggest that the afforestation density in this area should not exceed 1,500 trees/ha, and the stand structure should be optimized to obtain a canopy closure of less than 0.6, thereby ensuring sustainable forest development.