多尺度环境因子对神农架香溪河流域底栖藻类的影响

Influence of Multi-Scale Environmental Factors on Stream Benthic Algae Community in Xiangxi Watershed of Shennongjia

相比单一尺度的环境因子,多尺度环境因子能更全面的反映流域水生生物空间分布。以香溪河流域溪流底栖藻类为例,选择海拔、土地利用、水质和水文指标,采用偏冗余分析和偏典范对应分析对四季的底栖藻类营养硅藻指数(TDI)、物种丰富度和群落组成进行方差分解,分析大小尺度环境因子分别对底栖藻类空间分布的影响程度。结果显示:(1)TDI主要受到小尺度环境因子影响,解释率均为100%,无交互作用;(2)物种丰富度在不同季节分别受到大尺度和小尺度环境因子的影响,解释率均为100%,无交互作用;(3)底栖藻类组成主要受海拔的影响,并且与NO3-N有交互作用,为43%。虽然结果表明更多的小尺度环境因子对底栖藻类具有影响,但不能否认大尺度环境因子对整个流域底栖藻类分布的影响是长期而稳定的。

Compared with single-scale environmental factors, multi-scale environmental factors have a more comprehensive description of spatial distribution of aquatic life in the watershed. In Xiangxi watershed, altitude, land-use, water quality and hydrological fators were selected, and the Trophic Diatom Index(TDI), species richness and community composition were decomposed by Variation partitioning analysis in different seasons, using partial Redundancy Analysis and partial Canonical Correspondence Analysis to analyze the influence of large and small-scale environmental factors on the spatial distribution of benthic algae, respectively. The results showed that:(1) TDI is mainly influenced by small-scale environmental factors with 100% interpretation and no interaction;(2) Richness is influenced by large-scale and small-scale environmental factors respectively in different seasons with 100% interpretation and no interaction;(3) benthic algae composition is mainly influenced by altitude and altitude has an interaction with NO3-N at 43%. While the results show that more small-scale environmental factors have an impact on benthic algae, the impact of large-scale environmental factors on benthic algae distribution is long-term and stable in the watershed.