张掖黑河湿地附植硅藻群落初步研究——以张掖国家湿地公园为例

研究张掖国家湿地公园附植硅藻群落现状,为保护寒、旱区湿地水生植物与生物多样性提供理论依据。2017年夏、秋从张掖国家湿地公园浅水湖泊采集12种常见水生植物,采集植物上附植硅藻,并在水质富营养化评价的基础上进一步分析硅藻的种类分布、优势种、多样性和聚类性。结果表明,张掖国家湿地公园水体轻度富营养化;共检出附植硅藻39属158种(含变种),其中舟形藻属种类最多(18种),其次为菱形藻属(16种)、桥弯藻属(15种)和脆杆藻属(13种);Achnanthedium minutissimum为分布最为广泛的优势种,其次为Ulnaria acus和Encyonopsis subcryptocephala;Shannon-Weaver多样性指数在1.41~3.13,Pielou均匀度指数在0.58~1.07,均是秋季显著高于夏季(P<0.05,t-test);Cody指数与聚类分析表明,在同一时期内附植硅藻种类组成的相似程度和优势种分布对部分宿主植物的选择趋于一致,但也有部分宿主植物之间附植硅藻群落结构仍然存在较大差异。

A Preliminary Study on the Epiphytic Diatom Community in Zhangye Heihe Wetland: A Case Study of Zhangye National Wetland Park

In wetland ecosystems, aquatic plants provide both substrate and nutrients for epiphytic algae, and growth of epiphytic algae is antagonistic to growth of aquatic plants. Diatoms are an important epiphytic algae and widely used as a water quality indicator in rivers, wetlands and lakes, and a source of primary evidence for evaluation of biological integrity. In this study, we investigated the status of the epiphytic diatom community in Zhangye National Wetland Park, aiming to provide a theoretical basis for protecting aquatic plants and biodiversity in cold, dry regions. Zhangye Heihe wetland is an important ecological barrier of Hexi Corridor. In June (summer) and September (autumn) of 2017, 12 common aquatic plants and attached epiphytic diatoms were collected from shallow lakes in Zhangye National Wetland Park and species distribution, dominant species, diversity indices and clustering within the diatom community were analyzed. The water in Zhangye National Wetland Park was slightly eutrophic during the spring and summer of 2017. A total of 158 diatom species belonging to 39 genera were recorded, with dominance by Navicula (18 species), Nitzschia (16 species), Cymbella (15 species) and Fragilaria (13 species). Achnanthedium minutissimum was the most widely distributed species in the wetland park, followed by Ulnaria acus and Encyonopsis subcryptocephala. The Shannon-Weaver diversity and Pielou evenness indices of the epiphytic diatom community were in the ranges of 1.41-3.13 and 0.58- 1.07, respectively, and both indices were significantly higher in autumn than in summer (P<0.05, t-test). The Cody index and cluster analysis showed that diatom species composition and dominant species among the different host plants were similar, whereas community structure varied significantly among the host plants.