亚热带高山溪流底栖动物多维度alpha多样性及其驱动因子

Multidimensional alpha diversities of benthic macroinvertebrate in subtropical high-mountain streams and their driving factors

高海拔的溪流生态系统因其对外界干扰的响应敏感,被视为是监测环境变化和人类干扰的理想对象。本研究选取四川省天全县境内一条典型的亚热带高山溪流——天全河,于2018年4月和10月对上游20个样点进行调查,开展大型底栖无脊椎动物物种、功能和系统发育alpha多样性时空格局及驱动过程研究,旨在阐明在未受干扰的高山溪流中,底栖动物不同维度多样性的时空分布格局,并甄别出驱动多样性的关键环境因子和空间因子及其各自的相对贡献率。基于距离的线性模型分析显示,影响底栖动物物种多样性指数的关键环境因子为海拔和流速,关键空间因子为基于地理途径的PCNM 4~6等中尺度因子;而功能多样性指数受底质类型和浊度等环境因子以及地理途径PCNM 6~8和河网途径PCNM 3等空间因子的显著影响;系统发育多样性只受到海拔和底质类型等环境因子的显著影响。变差分解分析显示,环境因子(0.6%~21.5%)与空间因子(0.2%~16.6%)单独解释的物种多样性和功能多样性指数变异大体相当,表明两组因子都起到了重要的作用。环境因子对系统发育多样性指数变异的单独解释率(12.1%~23.3%)显著高于空间因子的单独解释率(0~6.9%),显示环境因子在驱动系统发育多样性指数的变异中占主导地位。本研究揭示了天全河上游底栖动物的多样性格局及驱动机制,研究结果可为进一步了解亚热带高山溪流底栖动物的多样性现状,并为其未来的多样性管理和环境保护提供重要的理论依据。

High-altitude stream ecosystems are sensitive to environment disturbance,and thusare considered as excellent indicators of environmental changes and human disturbance.This study focused on the Tianquan River,a representative subtropical high-mountain stream situated at Tianquan County,Sichuan Province.Surveys were carried out at 20 sampling sites along the upper reaches of the Tianquan River in April and October 2018.The aim of this study was to explore the spatio-temporal patterns and driving processes of taxonomic,functional and phylogenetic alpha diversity of benthic macroinvertebrates in the undisturbed high-mountain streams.Specifically,it sought to identify the key environmental and spatial factors influencing diversity,along with the relative contributions of the two sets of explanatory variables.Distance-based linear models analysis showed that significant environmental factors affecting taxonomic diversities were altitude and velocity,whereas the significant spatial factors were PCNM 4-6 based on overland distance.The functional diversity indices responded significantly to substrate type and turbidity(environmental factors),and overland distance-based PCNM 6-8 and watercourse distance-based PCNM 3(spatial factors).Only environmental factors(altitude and substrate type)significantly influenced phylogenetic diversity indices.Variation partitioning analysis indicated that the pure contributions of environmental factors(0.6%-21.5%)and spatial factors(0.2%-16.6%)accounted for similar amounts of variation in taxonomic and functional diversity indices,highlighting the significant roles of both sets of factors.The variation in phylogenetic diversity were better explained by environmental factors(12.1%-23.3%)than that explained by spatial factors(0-6.9%),highlighting the dominant role of environmental factors.This study unveiled the diversity patterns and driving mechanisms of macroinvertebrates in the upper reaches of the Tianquan River,offering crucial theoretical groundwork for comprehending the diversity status,management,and conservation of subtropical high-mountain stream ecosystems.