土地利用影响溪流底栖动物群落特征的空间尺度效应研究

It has become clear that the influence of land uses on stream ecosystem is scale-dependent. Therefore, understanding how the land use changes, impacted steam macroinvertebrates at multiple spatial scales is essential to explore the mechanism of degradation and recovery of stream macroinvertebrate communities, and thus it is helpful in biodiversity protection and impaired stream ecological recovery. Stream macroinvertebrates are influenced independently or interactively, directly or indirectly by factors at regional, watershed, riparian and local scales. However, researches related to terrestrial characteristics at different scales yielded mixed results. Moreover, present reports were mainly concentrated on watershed, riparian and local spatial scales, rare in regional scale. Li River, Qiantang River and Weihe watersheds in China are possess of distinct climate and geography character, different intensity of land uses and rich in macroinvertebrate diversity as well. In this proposal, we will investigate data of streams system, sub-watersheds, land use at different scales, stream habitats, water quality and macroinvertebrate in 1-3 order streams in above three watersheds. Furthermore, we will analyze relationships among environmental factors of different spatial scales, and factors with macroinvertebrate community by proper statistic methods. We aim to explore relative importance of multiscale environmental factors or stressors potentially to stream macroinvertebrate communities composition and structure, with the emphasis on the role of regional factors in shaping undisturbed and disturbed stream macroinvertebrate communities character among three watersheds. Our specific objects were 1) to describe differences in macroinvertebrate community composition and structure of non or little disturbed streams among regions, and to examine whether there were differences in the effect of factors on macroinvertebrate in a watershed; 2) to quantify the distinctive effects of stressors related to or resulted from watershed land use changes in shaping community structure among regions；3) to construct the response pattern models of macroinvertebrate community to land use changes at broad scales. It is hoped that our objects could provide a tool for proper evaluation of the influence of land use changes on stream ecosystems, stream ecological monitoring, impaired stream ecological recovery design, and evaluation of the effect of ecological recovery practice.

土地利用对溪流生态系统的影响与空间尺度有关。解析土地利用影响溪流底栖动物的空间尺度效应，有助于更科学地揭示底栖动物群落的退化和恢复机制。区域、流域、沿岸带和局部尺度环境因子综合作用于底栖动物，但现有研究集中在流域、沿岸带和局部尺度。项目拟以漓江、钱塘江中游、渭河水系西安地区河流所在流域的溪流为研究对象，应用GIS技术与方法提取水系和划分子流域，解译遥感影像来获得和计算不同空间尺度下的土地利用，结合水质、生境和底栖动物的野外调查、室内分析和鉴定数据，采有多元统计方法，探讨在受农田及城镇用地干扰情况下，区域尺度环境因子对流域间底栖动物群落特征变化的作用；探寻适合不同流域的，能高效反映农田城镇用地对底栖动物群落影响的最佳空间尺度，建立基于不同空间尺度环境因子的底栖动物群落对农田或城镇用地的响应模式。研究结果将对科学评价土地利用变化的生态效应、生态健康评价及受损溪流的生态恢复实践有积极作用。

土地利用是重要的全球变化现象，土地利用对群落结构和功能的影响也是生态和环境科学长期关注的重要内容。土地利用对水生态系统的影响的作用机制受所研究的空间尺度影响，同时与研究区域相关。项目调查了三个不同区域（热带区、亚热带区和温带区）的3个流域共191个样点的底栖动物、水质和生境指标，计算了样点所在上游流域和沿岸带两个空间尺度的森林、农业和城镇用地比例。采用多元线性回归法和方差分解法等探讨了两个空间尺度的土地利用与底栖动物群落组成与结构的关系，研究结果表明底栖动物群落组成与结构主要受流域尺度的农田和城镇用地变化决定，而不是沿岸带尺度的用地变化。不同流域间影响底栖动物群落结构的土地利用类型不同，在亚热带区的钱塘江中游流域总体上是城镇用地，其他两个流域总体上是农业用地。进一步分析温带区渭河流域两个生态区（秦巴山区常绿-落叶阔叶林生态区和汾渭河谷农业生态区）间土地利用变化与底栖动物群落的关系，结果表明山区影响底栖动物群落的是流域尺度的农业用地，而农业区影响底栖动物群落的是城镇用地。推测差异性可能与区域间、同一流域不同生态区间的自然环境梯度、土地利用背景及人为干扰强度有关。研究结论对预测土地利用变化对水生态系统的影响有较好的指导作用，对流域土地利用规划提供了参考的依据。项目还研究并确定了长三角地区163个溪流底栖动物分类单元的耐污值。共发表SCI论文6篇，核心期刊论文2篇。培养了1名博士生和3名硕士，国外学术交流2人。