物种多样性、功能多样性与生产力关系的尺度依赖效应——以内蒙古中温性草原为例

The relationship between biodiversity and ecosystem functioning has been the important research problem in ecology. Primary productivity of ecosystems is often regarded to as the integrative measure of ecosystem functioning. We can, therefore, gain much understanding about biodiversity -ecosystem functioning relationships by studying responses of primary productivity to changes in biodiversity. We propose to conduct vegetation surveys and collect data on plant species and functional diversities, primary productivity (peak above-ground biomass), and environmental factors (soil characteristics and climatic factors) in the Inner Mongolia temperate grassland biome. These datasets will allow us to explore relationships between the two kinds of biodiversity (species and functional diversity) with environmental factors. Importantly we propose to study this biodiversity-productivity relationship at four spatial scales - local, landscape, sub-regional, and regional. Three important questions will be addressed by our study. (1) What is the role of environmental factors in explaining the two kinds of biodiversity at four spatial scales? (2) How species diversity relates to functional diversity across the four spatial scales? (3) What are the forms of relationships between species diversity and productivity and functional diversity and productivity at the four spatial scales? Whether it is species diversity or functional diversity that is most important in determining productivity at the four scales? Our study is expected to make significant contributions and advance our understanding of the research problem. On the one hand, it will contribute to the theory of biodiversity-productivity relationship. On the other hand, the study is going to provide scientific support for the development of strategies of rational uses of grassland resources and restoration of damaged grassland ecosystems.

生物多样性与生态系统功能关系是近年来生态学研究的热点问题之一，研究生产力对生物多样性的响应是探讨生物多样性与生态系统功能关系的有效途径。本研究以内蒙古中温性草原为研究区，通过植被调查、土壤分析、气候因子空间模拟获得各样地物种多样性、功能多样性、生产力（高峰期地上现存生物量）及环境因子（土壤因子和气候因子）数据，并在局地、景观、亚区域及区域四个空间尺度下，分析物种多样性与功能多样性间，两种多样性分别与环境因子及生产力的关系。拟解决如下3个科学问题：（1）不同空间尺度，影响物种多样性及功能多样性的主导环境因子是什么？（2）不同空间尺度，物种多样是否与功能多样性共同变化？（3）不同空间尺度，物种多样性、功能多样性与生产力的关系如何，哪种多样性与生产力关系更密切？在丰富多样性与生产力关系理论研究的同时，为草地资源合理利用及受损生态系统恢复提供科学支持，具有理论及实践的双重意义。

生物多样性与生态系统功能关系是生态学研究的热点问题之一。本项目以内蒙古中温性草原为研究区，分析了多样性的分布格局及维持机制，并在此基础之上探讨了物种多样性与功能多样性关系，以及二者对生产力贡献及维持机制。主要研究结论如下：. （1）内蒙古草原物种多样性格局呈现随纬度、经度增加而增加的趋势，水热动态假说最适合解释该区的物种多样性格局。. （2）内蒙古草原Gamma多样性来源于Alpha与Beta多样性共同作用，且Beta多样性作用高于Alpha多样性；在降水较低的地区，区域种库作用对于Alpha多样性维持更为重要，在降水丰富地区，局地生态过程重要性更高；随着降水量的增加，Beta多样性的维持机制由生态位过程为主逐渐转换为扩散过程为主。. （3）内蒙古草原物种多样性与功能多样性间呈现S型曲线关系。在降水极端匮乏情况下，物种多样性增加，并不会导致功能多样性的增加；当降水量达到一定程度时，物种多样性的增加会强烈地增加功能多样性；随着降水量的增加，物种多样性对功能多样性的正效应逐渐减弱。. （4）无论是内蒙古草原还是不同降水梯度草原区，功能多样性对生产力的贡献均强于物种多样性。. （5）在降水较低的草原区，选择效应与互补效应在群落生产力维持中共同作用；随着降水量的增加，选择效应在群落生产力维持中起主导作用。针对内蒙古草原，选择效应在功能多样性维持生产力中起主导作用。. （6）在降水较低的草原区，叶面积大小是影响群落生产力的主要功能性状；随着降水量的增加，高度成为决定生产力的主导功能性状。针对内蒙古草原，高度是决定内蒙古草原生产力最主要的植物性状，解释了群落生产力57.1%的变异。