香溪河附石性大型底栖动物功能摄食类群研究

RESEARCH OF FUNCTIONAL FEEDING GROUPS OF MACROINVERTEBRATES IN THE STONY HABITAT OF THE XIANGXI RIVER SYSTEM

利用1∶50 000地形图对香溪河进行划分,显示香溪河为一条6级河流。分析包括捕食者(PR)、撕食者(SH)、刮食者(SC)、直接收集者(GC)和过滤收集者(FC)在内的5个主要功能摄食类群的组成,发现香溪河主要摄食类群以直接收集者和刮食者为主。各功能摄食类群的密度和生物量随着河流级别的变化而发生变化,基本趋势为:直接收集者和滤食者的密度和生物量都随着河流级别的增加而增大;撕食者和刮食者的密度和生物量的密度随着河流级别的增加而减小;而捕食者在整个流域内的密度上游小于下游,生物量却是上游大于下游。研究结果表明香溪河在夏季其上游物质来源以附石性藻类生产为主,下游则以异源性细有机颗粒输入为主。此外,功能摄食类群的密度与部分环境因子具有显著的相关性:过滤收集者与Ca2+和河宽相关,收集者与SiO2相关显著,刮食者与海拔和氨氮相关性较高,撕食者与电导和PO4-P相关性较高。

The stream of Xiangxi River system was divided into six orders based on 1：50 000 relief maps. A total of fifty-three sampling sites were sampled. The macroinvertebrate communities were divided into five main functional feeding groups, including predators （PR）, shredders （SH）, scrapers （ SC）, collectorgatherers （GC） and collector-filterers （FC）. The collector-gatherers and scrapers, which feed on benthic algae, riparian detritus and fine particulate organic matter from the stream bottom, were the main groups in Xiangxi River system. The density and biomass of different functional feeding groups changed in the different stream orders. The GC and FC increased with the rising of stream order, while the SH and SC decreased. The PR density was higher in the downstream and biomass was higher in the upstream. The trend showed that the autochthonous energy dominated in the up-stream and the input of allochthonous energy dominated in the down-stream. The relationship between density of functional feeding groups and environmental factors was analyzed. Results showed that FC was significantly correlated with the width of river and Ca^2＋. The GC and SiO2 were highly correlated. The relationship between the SC and the elation and ammonia was significant. And the relationship between the SH and the PO4-P and conductivity was also important.