环境因子对河流底栖无脊椎动物群落结构的影响

底栖无脊椎动物是河流生态系统的重要组成部分,在物质循环和能量流动中是不可或缺的重要环节。其群落结构特点与河流环境因子密切相关,能较好地反映河流生态系统健康状况。综述了物理因子(底质、温度、水深、水流、洪水干扰等)、化学因子(溶氧量、p H值、磷、氮等)、生物因子(水生植物、竞争和捕食)、人为干扰(电站建设、城镇化等)和综合因子对河流底栖无脊椎动物群落结构的影响,并根据国内外研究现状指出水流、海拔和洪水干扰等环境因子对河流底栖无脊椎动物群落结构影响的研究较少或不足,对这些环境因子的研究应是今后河流生态学领域需要着力推进重要内容。深入研究和完善环境因子与底栖无脊椎动物群落结构的关系可为保护底栖无脊椎动物群落、流域水生态系统管理和受损河流生态系统修复提供更为全面的科学依据。

The effects of environment factors on community structure of benthic invertebrate in rivers

Benthic invertebrate refers to aquatic animals living at the bottom of water in the all or part of life history. As an important component in river ecosystem, it is also an indispensable connection link in energy flow and matter cycle. Benthic invertebrates are characterized by long life cycle, slow action, broad range of types and large body size, which are convenient for collection and observation. The distribution, abundance and diversity of benthic invertebrate can convey information of environmental pollution. Some groups display strong resistance against severe environment, while other groups are sensitive to changes in environmental conditions. The characteristics of benthic invertebrate reflect the health state of river ecosystem. Benthic invertebrate is one type of significant indicator organisms in river health assessment. At present, many scholars mainly focused on river health assessment and the effects of a few environmental factors on benthic invertebrate community structure. The effects of environment factors on community structure of benthic invertebrate are very complex: there are numerous environment factors and the effects of different environment factors on different benthic invertebrate groups are not completely the same. This article discusses the influences of environment factors including physical factors (bottom sediment, water temperature, water depth, water current, etc.), chemical factors (dissolved oxygen, total phosphorous,total nitrogen, etc.), biological factors (aquatic plants, competition and predation), anthropogenic disturbance and other combined factors on community structure of benthic invertebrate. Different environment factors impose different impacts on benthic invertebrates. Bottom sediment is an essential condition for all life activities including growth, reproduction, etc. Any species has the strict living temperature range. Community structure of benthic invertebrate is directly influenced by the fluctuation of temperature. Water depth is one of major environment factors of community structure of benthic invertebrate. In general, the density and biomass of benthic invertebrate continuously vary with water depth. Water flow not only affects feed conditions of benthic invertebrate, rivers productivity, competition among species and within species, larval living places, but also has significant impacts on the community structure of river. Flow velocity determines the composition of benthic invertebrate community. Altitude determines the changes of temperature, light and other environment factors and indirectly affects the community structure of benthic invertebrate. Water chemical factors are closely related to community structure of benthic invertebrate. Aquatic plants provide excellent habitat fields for propagation, feeding and living for benthic invertebrate. Benthic invertebrates are affected by both competition and predation: excessive competition and predation often result in the reduction in species diversity, secondary productivity and feeding conditions as well as the changes in community structure of benthic invertebrate. Anthropogenic disturbance (such as power plant construction, thermal discharge and urbanization) is mainly response for the changes of the community structure of benthic invertebrate. The effects of water flow, water velocity, altitude and flood on community structure of benthic invertebrate are seldom reported. These environment factors should be perfected and investigated in the future.