鄱阳湖都昌自然保护区浮游甲壳动物群落时空分布特征及其驱动因子

Spatio-temporal distribution characteristics and driving factors of planktonic crustacean community in Duchang Nature Reserve of Lake Poyang

江西省都昌候鸟省级自然保护区作为鄱阳湖流域内占地面积最大的自然保护区,承担着保护世界性和国家重点保护濒危越冬候鸟资源等重要责任。探究都昌候鸟自然保护区浮游甲壳动物群落结构及其主要影响因子,可为都昌保护区内鸟类栖息地的生境保护与动态评估提供科学依据。20192021年1、4、7和10月对都昌保护区内4个区域的浮游甲壳动物的密度、生物量和水环境因子进行采样调查,运用多样性指数、Pearson相关性和冗余分析(RDA)等对都昌保护区水质情况以及浮游甲壳动物与水环境因子和叶绿素a之间的关系进行解析。结果显示,调查期间共鉴定出浮游甲壳动物31种,其中枝角类(20种)和桡足类(11种)。都昌保护区浮游甲壳动物年均密度213.81 ind./L,年均生物量为1.51 mg/L。都昌保护区浮游甲壳动物群落结构时空变化较大,季节上,夏季或秋季浮游甲壳动物的生物量达到峰值,冬季浮游甲壳动物种类最少;空间上南矶一般区(D4)浮游甲壳动物密度和生物量较大,其次是撮箕湖一般区(D3),小矶山核心区(D1)和三山核心区(D2)差异较少。根据多样性指数和均匀度指数分析都昌保护区水质情况,结果表现为撮箕湖一般区(D3)水质环境最好,其次是小矶山核心区(D1),最后是三山核心区(D2)和南矶一般区(D4)。简弧象鼻溞(Bosmina coregoni)作为都昌保护区优势种,这从侧面反映出都昌保护区水体呈富营养化,与调查期间发现局部出现蓝藻水华相吻合。都昌保护区浮游甲壳动物群落结构的时空演替主要是由总氮、叶绿素a、水位和水温等因素共同决定。不同季节影响浮游甲壳动物群落结构的主导因素也不相同,冬季主导因素主要是总氮、总磷和溶解氧;夏季主导因素是水位和叶绿素a;秋季主导因素主要是水温、水位、透明度、叶绿素a、溶解氧和总磷。

As the largest nature reserve in the Lake Poyang Basin,Duchang Migratory Bird Provincial Nature Reserve in Jiangxi Province plays an important role in protecting worldwide and national key rare and endangered wintering migratory birds.Exploring the zooplankton community structure and its main influencing factors in Duchang Migratory Bird Nature Reserve can provide a scientific basis for the habitat protection and dynamic assessment of bird habitats in Duchang Nature Reserve.In January,April,July and October 2019-2021,the density,biomass and water environment factors of planktonic crustaceans in four areas in Duchang Nature Reserve were investigated,and the water quality in Duchang Nature Reserve and the relationship between floating animals and water environment factors and chlorophyll-a were analyzed by using biodiversity index,Pearson correlation and redundancy analysis(RDA).The results showed that 31 species of planktonic crustaceans were identified during the investigation,including 20 species of cladocera and 11 species of copepoda.The annual average density of planktonic crustaceans in Duchang Nature Reserve was 213.81 ind./L,and the annual average biomass was 1.51 mg/L.The community structure of crustacean plankton in Duchang Nature Reserve greatly changed across time and space.In seasons,the biomass of planktonic crustaceans peaked in summer or autumn,and the richness of crustacean plankton were the least in winter;Spatially,the density and biomass of planktonic crustaceans in the general area of Nanji(D4)were larger than the general area of Cuojihu(D3),and there was little difference between the core area of Xiaojishan(D1)and the core area of Sanshan(D2).According to the diversity index and evenness index,the water quality of Duchang Nature Reserve was analyzed.The results showed that the water quality environment of the general area of Lake Zuoji(D3)was the best,followed by the core area of Xiaoji Mountain(D1),and then the core area of Sanshan Mountain(D2)and the general area of Nanji(D4).Bosmina coregoni also reflected the gradual eutrophication of the water body in the Duchang Nature Reserve,which was consistent with the local occurrence of cyanobacteria bloom during the investigation.The temporal and spatial succession of planktonic crustacean community structure in the Duchang Nature Reserve was mainly determined by total nitrogen,chlorophyll-a,water level and water temperature.The dominant factors affecting crustacean plankton were different in seasons,i.e.total nitrogen,total phosphorus and dissolved oxygen in winter,water level and chlorophyll-a in summer,and water temperature,water level,transparency,chlorophyll-a,dissolved oxygen and total phosphorus in autumn,respectively.