基于中国生态系统研究网络的典型森林生态系统土壤保持功能分析

Use of CERN for estimating the soil conservation capability of typical forest ecosystems in China

森林生态系统土壤保持功能在控制土壤侵蚀以及维持生态安全方面具有不可替代的作用。根据不同气候带降雨特征进行降雨侵蚀力参数校正,基于中国生态系统研究网络(CERN)的森林生态系统长期定位观测样地2005-2015年监测数据利用修正的通用土壤流失方程(RUSLE)定量分析了典型森林生态系统土壤保持功能的时空变化特征,并探讨了土壤保持功能的影响因素。研究结果表明:①日雨量侵蚀力模型在降雨丰富的热带模拟效果优于降雨相对较少的亚热带和温带,参数校正后模拟效果明显提升;②研究期内10个典型森林生态系统土壤保持量变化范围为4.44-891.67 t hm^-2 a^-1,呈现北低南高的空间格局(R^2=0.65***);土壤保持率均达到97%以上;③降雨、归一化植被指数、土壤质地和植被林龄是影响森林生态系统土壤保持功能的主要影响因素;降雨量与土壤保持量显著相关(R^2=0.52*),NDVI和土壤质地与实际土壤侵蚀量显著相关(R^2=0.64**,R^2=0.41*),植被林龄主要影响土壤保持率的变化速率。

The conservation of forest soil can significantly affect soil erosion and ecological security.In this study,rainfall erosivity was optimized on the basis of the rainfall characteristics of different climatic zones.The soil conservation capability of forest ecosystems was quantitatively estimated using the revised universal soil loss equation,which is based on long-term observational data of the Chinese Ecosystem Research Network,and both spatial and temporal variations were analyzed.①The simulation results of the daily rainfall erosion model in tropical regions with high rainfall were better than those in subtropical and temperate regions.After parameter optimization,the simulation effect of the subtropical and temperate regions was significantly improved.②From 2005 to 2015,the amount of soil conservation by forest ecosystems ranged from 4.44 to 891.67 t hm^-2 a^-1.The soil conservation capability exhibited a significant spatial pattern,with an increasing trend from north to south(R^2=0.65***),and the soil erosion rates were all greater than 97%.③Precipitation exhibited a significant positive correlation with soil conservation(R^2=0.52*),and both normalized difference vegetation index(NDVI)and soil texture exhibited strong correlations with realistic erosion(R^2=0.64**,R^2=0.41*).There was a power function relationship between vegetation age and the rate of change of soil conservation.