不同类型景观水体浮游动物群落差异及其影响因素

探明不同类型景观水体中环境敏感型浮游动物群落特征差异及影响因素对景观水体生物多样性维持和水生生态系统保护十分重要。于2014年5月在上海选取具代表性的8个景观水体共设置35个采样点进行浮游动物采样调查,并同步测定水体环境指标。本次调查采集并鉴定浮游动物40种,其中轮虫29种,枝角类7种,桡足类4种。基于浮游动物群落组成进行聚类分析,所有采样点聚为四种景观类型:天然湖泊(淀山湖)、人工湖泊(滴水湖)、AAAA级公园水体(共青森林公园和古猗园)和普通综合性公园水体(世纪公园、和平公园、长风公园和车镜公园)。两种公园水体浮游动物种类较为丰富,多样性较高,各自约有40%的种为生境特有种,而淀山湖特有种仅1种(为猛水蚤),滴水湖3种均为蛭态类。物种相似性方面,大型天然淀山湖与人工滴水湖相似性最高(37.5%),普通公园水体次之(33.3%),与AAAA公园水体相似度最低(20%)。后两者间的相似性较高(27.8%),且两者与滴水湖的相似度均较低(18.5%和12.0%)。四类水体仅有3个共有种/类群:角突臂尾轮虫(Brachionus angularis)、螺形龟甲轮虫(Keratella cochlearis)和桡足类无节幼体。AAAA公园水体中甲壳纲动物的相对丰度(88.8%)远高于其他水体,其优势种由3种大型浮游动物(甲壳纲)组成,普通公园水体优势种仅由4种小型浮游动物(轮虫)组成,淀山湖和滴水湖的群落结构简单,优势种单一。冗余分析(RDA)显示,水温、透明度、pH、化学需氧量、氨氮和总磷是影响景观水体浮游动物群落差异的显著环境因子。

Characteristics of zooplankton community in different types of landscape waters and their influencing factors

Identifying the differences in environment-sensitive zooplankton community characteristics and influencing factors among different types of landscape waters is critical for maintenance of biodiversity and protection of aquatic ecosystem. Zooplankton was sampled from 35 sites in 8 typical landscape waters in Shanghai and in situ physicochemical variables were measured in May 2014. A total of 40 species of zooplankton were recorded in the study area, of which 29 species were recorded as Rotifera, 7 species as Cladocera, and only 4 of them as Copepoda. Cluster analysis showed the zooplankton communities in all sampling sites were clustered into four groups:natural fresh-water lake (Lake Dianshan), man-made lake (Lake Dishui), waters in AAAA grade parks (Gongqing Forest Park and Guyiyuan Park), and waters in ordinary comprehensive parks (Century Park, Heping Park, Changfeng Park, and Chejing Park). Zooplankton species in the two types of park were richer, of which about 40% were endemic species. While there was only 1 endemic species (Harpacticoida) in Lake Dianshan, and three endemic species (Bdelloidea) in Lake Dishui. In terms of species similarity, the natural Lake Dianshan had the highest similarity (37.5%) with the man-made Lake Dishui, followed by ordinary parks (33.3%), and AAAA grade parks (20%). The species similarity between the latter two was higher (27.8%), while Lake Dishui had a lower similarity with the latter two (18.5% and 12.0%). There were only three taxa (Brachionus angularis, Keratella cochlearis and Copepoda nauplii) detected in all types of waters. The relative abundance of crustaceans in waters of AAAA grade park (88.8%) was much higher than that in other waters. The dominant species in waters of AAAA grade parks were composed of three large-size zooplankton species (crustaceans). The dominant species in waters of ordinary comprehensive parks were composed of four small-sized zooplankton species (rotifers). The community structures in both Lake Dianshan and Lake Dishui were simple. Redundancy analysis showed water temperature, transparency, pH, and chemical oxygen demand were significant factors affecting zooplankton community structure in landscape waters.