黄土高原种子植物多样性分布格局与环境解释

Geographic Patterns and Environmental Determinants of Seed Plants Species Richness in the Loess Plateau

物种丰富度的地理分布格局及成因一直是宏观生态学、生物地理学和保护生物学研究的核心问题。黄土高原是我国生态关键脆弱区,生物多样性保护面临严峻形势,了解该区域物种多样性格局与环境因子之间的关系对于生物多样性保护对策的制定具有重要意义。通过收集黄土高原自然保护区种子植物分布数据,结合气候、生境异质性和人为干扰等环境因子,探讨黄土高原种子植物丰富度格局及其主要环境解释。结果显示,黄土高原种子植物多样性由东南向西北逐渐递减,且山地自然保护区物种多样性更高。最优线性回归结果表明,降水因子、海拔范围、净初级生产力范围和人类足迹是决定黄土高原种子植物分布格局的重要因素;方差分解结果表明,气候、生境异质性和人为干扰能够解释黄土高原种子植物密度和丰富度52.0%~53.4%的变异,其中,气候和生境异质性的相对贡献远大于人类干扰的相对贡献。黄土高原自然保护区应建立在水热条件良好且人为干扰较少的山地,将有利于保护种子植物多样性。

The geographical distribution pattern of species richness and its influencing factors have always been the core issues of macroecology,biogeography and conservation biology.The Loess Plateau is a key ecological fragile area in China,and the biodiversity conservation in the region is suffering a severe degradation situation.Understanding the relationship between species diversity and environmental factors is essential for formulating biodiversity conservation strategies.Here,the distribution pattern of seed plant richness in the Loess Plateau and its main environmental interpretation were discussed based on records of seed plants in the nature reserves,as well as their corresponding climate,habitat heterogeneity,and human disturbance factors.The results show that the diversity of seed plants in the Loess Plateau decreases gradually from southeast to northwest,and the species diversity in mountain nature reserves are the highest.Optimal multivariate linear regression show that precipitation,altitude range,net primary productivity range and human footprint are important factors to determine the distribution pattern of seed plants in the Loess Plateau.Variance decomposition show that climate,habitat heterogeneity and human disturbance can explain 52.0%-53.4% of the variation sources of seed plant density and richness,and the relative contribution of climate and habitat heterogeneity is far greater than that of human disturbance.Nature reserves in the Loess Plateau should be established in the mountainous area with abundant hydrothermal and little human disturbance conditions,which is an optimal strategy to protect seed plants diversity of the Loess Plateau.