太湖岸带湿地土壤动物群落结构与多样性

Community structure and diversity of soil animals in the Lake Taihu lakeshore wetland

土壤动物是湿地生态系统物质循环和能量流动的关键环节,也是湿地生态系统演化的重要驱动因子。2010年4月—2011年2月研究了太湖岸带湿地4种生境类型(A酸模岸带、B乔灌岸带、C农作物岸带、D天然芦苇岸带)中的土壤动物群落结构和多样性。4次调查共分离到土壤动物3575只,隶属4门12纲,共有105类,土壤动物群落密度达到2794.49—67766.39个/m2。在大类群中,节肢动物门(Arthropoda)为优势类群,占总个体数的55.75%,其次为线虫动物门(Nematoda),占总个体数的36.27%;节肢动物门和线虫动物门构成了该区土壤动物的主体,对土壤动物群落特征起着决定性作用。土壤动物群落各多样性指数的季节变化动态不同,Pielou均匀度的方差分析表明:2010年4月份类型A与类型C之间存在显著性差异(P<0.05);而Shannon多样性方差分析表明:2011年2月份类型A与C、D存在显著性差异(P<0.05)。土壤动物的整体数量表现为2010年4月>2010年11月>2010年8月>2011年2月。Sorensen和Morisita-Horn相似性分析说明不同生境类型对土壤动物物种丰度产生了不同的影响。太湖岸带湿地土壤动物个体数量在垂直分布上均有一定的表聚性,但不同季节表聚性程度不同。研究结果可为太湖岸带湿地的健康评价及科学管理提供理论依据。

Soil animals, a crucial part of wetland ecosystems, play an important role in nutrient cycling and energy flow and are also an important driver of wetland ecosystem succession. Research related to the diversity of soil animals is an important part of the study of soil biodiversity. Knowledge of the temporal variability of soil animal populations and species is crucial to the understanding of soil community dynamics and food webs. Lake Taihu, a shallow freshwater lake located in eastern China on the border of Jiangsu and Zhejiang provinces, was studied to document the composition, diversity, and seasonal variations of soil animal communities in a lakeshore wetland. Soil animal community structure and diversity were analyzed in four different types of lakeshore habitat： A, Rurnex acetosa lakeshore; B, tree and shrub lakeshore; C, crop lakeshore; D, natural reed lakeshore. Tullgren and Baermann＇s methods were used to extract 3575 soil fauna individuals （ind） which were classified into four phyla, twelve classes, and 105 taxonomic groups. The density of soil animal communities was 2794.49- 67766.39 ind/m2. Species in the phyla Arthropoda （55.75%） and Nematoda （36.27%） constituted the main body of thesoil fauna. The proportion of animals in different groups varied widely from one community to another： for example, in the phylum Arthropoda, Insecta, Collembola and Arachnida accounted for 22.74%, 16.92% and 8.85% of the individuals in the soil fauna community, respectively. A test of the differences in population density of soil animal communities in different habitats indicated habitat types C and A were significantly different from habitat B （F=4.319, P 〈 0. 05） in April 2010. In August and November 2010, the density of these communities was significantly lower in habitat A than in the other three types （F= 4.331 ; F= 6.555, P 〈 0. 05）. Also, in February 2011, the density was significantly lower than in type C and D （F= 2.042, P 〈 0. 05）. At other times, no significant differences in the density of soil animal communities were observed for all habitat types （P 〉 0. 5）. The dynamics of several soil fauna community diversity indices varied in different seasons. The Simpson diversity index reached a maximum for habitat types B, C and D in April 2010, with values of 0.44, 0. 59 and 0. 34, respectively; meanwhile, the same index for type A reached a maximum of 0. 55 in February 2011. For the Pielou evenness and Shannon diversity indices, type B, C and D reached a minimum in April 2010, while type A reached a minimum in February 2011. The Simpson diversity index difference test indicated types B and C were significantly different from type D （ F= 1.878, P 〈 0.05 ） in August 2010. Types A and C were significantly different for the Pielou evenness index in April 2010 （ P 〈 0. 05 ） ; and in August 2010, Type B was significantly lower than the other three types （ H = 5. 052, P 〈 0. 05）. Meanwhile, in November 2010, Type A was significantly lower than the other three types （F= 3.271, P 〈 0. 01 ） for the Shannon diversity index, and types A and C were significantly different from type D in February 2011 （P 〈 0. 05 ）. When combining the four types as a single measurement, the overall reserves of the soil animals were in descending order of April 2010 〉 November 2010 〉 August 2010 〉 February 2011. Sorensen index similarity analysis showed that the seasonal similarity of the four types of Lake Taihu lakeshore wetland soil animal communities was different. The seasonal variation had higher impact on the number of Type A dominant communities. Morisita-Horn index analysis showed that different habitat types produced different effects on the abundance of soil animal species. This suggested that seasonal change can influence the structure and composition of the soil community. The vertical distribution of the number of individuals of the soil fauna had a certain degree of accumulation, with a greater number of individuals found in the surface layer of the soil, although the exact numbers varied in different seasons. The results of this study provide a basis for health assessment and scientific management of Lake Taihu lakeshore wetland.