ABSTRACT

Anthropogenic pressures on standing waterbody systems potentially result in changes to sediment and water qualities, and thus ecological community characteristics. We tested effects of drawdown on physical, water and sediment variables, as well as their effects on littoral macroinvertebrate community composition in two subtropical reservoirs. Water levels differed significantly between reservoirs and over time, with significant effects on several water chemistry parameters (e.g., pH, conductivity, Mg, Fe), whilst sediment properties were less affected. Significant effects of water level, site and macrophyte cover on macroinvertebrate community structures were not detected, however macroinvertebrate community structuring differed significantly over time. Redundancy analysis (RDA) highlighted that the first and second axes accounted for 45.6% of the total macroinvertebrate community and environmental variables relationship variance. Most of the sediment variables, such as Cu, Mg, Na and Pb and water chemistry (i.e., HCO3-), were positively associated with the first axis, while water temperature and pH were negatively associated with the first axis. The RDA variation partitioning showed that water and sediment chemistry variables accounted for 40.3% and 30.3%, respectively, of the total macroinvertebrate variation. The present study contributes to understandings of the interplays between water level, physico-chemical properties and community compositions in human-altered aquatic ecosystems.

摘要

站立水体系统上的人为压力有可能导致沉积物和水质的变化，从而导致生态群落特征的变化。我们测试了水位下降对物理，水和沉积物变量的影响，以及它们对两个亚热带水库沿岸大型无脊椎动物群落组成的影响。水库之间的水位差异很大，并且随着时间的流逝，对几个水化学参数（例如，pH，电导率，Mg，Fe）有显着影响，而对沉积物特性的影响较小。未检测到水位，位点和大型植物覆盖对大型无脊椎动物群落结构的显着影响，但是大型无脊椎动物群落结构随时间变化显着。冗余分析（RDA）强调，第一轴和第二轴占45。大型无脊椎动物群落总数的6％与环境变量之间的关系具有方差。大部分沉积物变量（例如Cu，Mg，Na和Pb和水化学（即HCO3-））与第一轴呈正相关，而水温和pH值与第一轴呈负相关。RDA变异分区显示，水和沉积物化学变量分别占总无脊椎动物总变异的40.3％和30.3％。本研究有助于人们改变的水生生态系统中的水位，理化性质和群落组成之间的相互作用。与第一轴呈正相关，而水温和pH与第一轴呈负相关。RDA变异分区显示，水和沉积物化学变量分别占总无脊椎动物总变异的40.3％和30.3％。本研究有助于人们改变的水生生态系统中的水位，理化性质和群落组成之间的相互作用。与第一轴呈正相关，而水温和pH与第一轴呈负相关。RDA变异分区显示，水和沉积物化学变量分别占总无脊椎动物总变异的40.3％和30.3％。本研究有助于人们改变的水生生态系统中的水位，理化性质和群落组成之间的相互作用。