天鹅洲长江段底栖动物的群落结构与季节变化

探究长江天鹅洲白鱀豚国家级自然保护区长江段底栖动物的群落结构及季节变化,可为该区域水生生物的保育和管理工作提供基础资料和科学依据。2014-2015年,按季节在干流江段设置16个采样站位,进行底栖动物调查和水质理化指标测定,并同步收集当月水位信息。结果表明,4次调查共检出底栖动物53种,其中水生昆虫28种,软体动物9种,寡毛类9种,甲壳动物4种,其他类群3种,常见种为日本沼虾、钩虾、栉水虱、米虾、河蚬、淡水壳菜、多足摇蚊、环足摇蚊和齿斑摇蚊。底栖动物存在较为明显的季节演替,且种类组成较为简单,以小个体的物种和活动能力较强的甲壳类为主。低水位时,生境异质性的升高有利于底栖动物多样性的增加;而高水位时生境异质性的降低,则对底栖动物的多样性不利。水位的升高以及流量的增大,有利于活动能力较强的甲壳动物生存和扩散。底栖动物的密度、生物量以及多样性处于较低水平,与该河段地处下荆江、河道演变剧烈、生境不稳有关,密度水平与长江中游的沙市、黄石断面接近,表明目前底栖动物密度处于较低水平是一种常态现象。

Community Structure and Seasonal Variation of Macroinvertebrates in the Tian-e-zhou Oxbow, Yangtze River

In this paper, the community structure and seasonal variation of macroinvertebrates in the section of Baiji National Natural Reserve of the Tian''e Zhou in Yangtze River were studied, to provide basic data and scientific basis for the conservation and management of aquatic organisms in the region. From 2014 to 2015, 16 sampling sites were set up in the river section according to season to conduct the macroinvertebrate surveys and water quality monitoring, and synchronously collect water level information in the same month. A total of fifty-three species (28 species of aquatic insects, 9 species of mollusks, 9 species of oligochaetes, 4 species of crustaceans and 3 species of other groups) were collected in the four surveys. The common taxa were Macrobrachium nipponense, Gammarus sp., Asellidae sp., Caridina sp., Corbicula fluminea, Limnoperna lacustris, Polypedilum sp., Cricotopus sp., and Stictochironomus sp. The results showed that the macroinvertebrate communities with obvious seasonal succession, and relatively simple taxa composition, were mainly composed of small body-size taxa and crustaceans with strong activity ability. At low water level, the increase of habitat heterogeneity was conducive to the increase of biodiversity, while at high water level, the decrease of habitat heterogeneity was not conducive to the diversity of macroinvertebrates. The increase of water level and discharge was conducive to the survival and dispersion of crustaceans with strong mobility. The density, biomass and biodiversity of macroinvertebrates in the river section were at a low level, which was related to the severe channel evolution and unstable habitat in the lower Jingjiang reach. The density level was close to that of the sections Shashi and Huangshi and within the range of density variation which reported in the middle reaches of the Yangtze River, indicating the current low density of macroinvertebrates was a normal phenomenon