中文摘要：

以底栖动物为指示物种对天然破碎河段进行野外调查,并开展野外试验对天然河段进行人工隔离和定期采样分析,研究了栖息地隔离对底栖动物组成及河流生态的影响。结果表明,溶解氧含量在各隔离区中变化不一致;隔离区内动物密度、丰度和多样性均降低,隔离程度越高,降低越显著。从动物组成来看,蜉蝣目和双翅目的相对密度在隔离区中显著降低,蜻蜓目和双壳纲则增加。河流栖息地被隔离后,底栖群落经过一段波动周期后才表现出规律性变化趋势。由于水生昆虫在成虫阶段的飞行扩散,隔离区与天然河流之间仍存在较高的动物流通,但隔离区内的动物组成并不完全是天然河段内的子集。结合研究结果和中国河流实际,提出了保护河流生态及生物多样性的建议和对策。

英文摘要：

The field investigations and an experiment were conducted in the Juma river in the suburbs of Beijing to study the effect of habitat fragmentation on river ecology, using benthic macro-invertebrates as indicator species. Three experimental plots were isolated from a relatively undisturbed stream habitat with sheet iron. The benthic assemblages and water parameters were measured by sampling periodically. The results indicate that the abundance, taxa richness and bio-diversity of invertebrates significantly decrease in the experimental plots owing to the habitat isolation. The smaller the experimental habitat plot, the more significantly these biotic indices decrease. The contents of the dissolved oxygen in the studied plots present the inconsistent variations. The comparison of the benthic communities shows that the relative abundances of Ephemeroptera and Diptera reduces significantly in the isolated plots, and that of the Odonata and Lamellibranchia increase significantly. It is also found that the benthic communities need some time to stabilize after isolation, and then present apparent variation over time. There is a relatively high degree of taxa turnover between isolated plots and the non-isolated reach, which can be attributed to the flight and dispersal of many aquatic insects in their adult stage. However, the benthic communities in isolated plots are not nested subsets in the natural non-isolated stream. This paper also gives some suggestions of the river restoration and the preser- vation of river ecological integrity based on the study and the present status of the rivers in China.