钨尾矿重金属污染对茶园土壤动物群落结构及多样性的影响

Effect of Heavy Metal Pollution on the Community Structure and Diversity of Soil Animals in Tea Garden Located in A Tungsten Mining Area

土壤动物对土壤理化环境变化响应十分敏感,土壤动物群落结构及多样性可以用于指示钨尾矿区土壤重金属污染程度。以钨尾矿下游区不同污染程度的茶园生境为研究对象,采用样方法系统调查了3个生境土壤动物群落的组成、结构、多样性及环境变化特征,利用NMDS、ANOSIM等比较不同生境土壤动物群落的相似性,运用RDA排序结合重金属污染指数分析土壤动物群落结构与土壤环境因子的关系。结果表明:未污染茶园土壤动物的个体数量、类群数、物种丰富度和多样性指数均显著高于污染茶园I和Ⅱ,而污染茶园Ⅱ土壤动物个体数、类群数和物种丰富度又显著高于污染茶园I;未污染茶园土壤动物均匀度指数显著高于污染茶园Ⅱ。土壤有机质是影响土壤动物分布的主要环境因子(51.42%),其次是全氮(贡献率9.08%)、全磷(贡献率11.21%)、速效磷和全钾(贡献率9.61%),它们均与土壤动物个体数和类群呈正相关。进一步分析发现,Ni、Cd、As和Cu等重金属是茶园的主要污染因子,它们显著降低了茶园Ⅰ和茶园Ⅱ土壤有机质(63.8%和58.5%)、全氮(61.7%和65%)和速效磷(55.9%和8.8%)含量,Ni、Cd和As是抑制茶园土壤动物群落分布的主要毒性因子,其解释率分别为46.55%、14.14%、9.83%。重金属污染降低了茶园土壤养分可利用性,重金属污染指数抑制土壤动物的类群和个体数量增长,土壤动物群落的丰富度指数、多样性指数和优势度指数随重金属污染程度的加重而降低。

Soil animals are very sensitive to soil physical and chemical environmental changes,and the community structure and diversity of soil animals can be used to indicate the degree of soil heavy metal pollution in the tungsten tailings area.This paper selected the tea garden habitats with different pollution levels in the lower reaches of the tungsten mining area as the research object,using sample methods to systematically investigate the community structure and diversity of soil animals.In the same time,we also collected soil samples in order to determine soil physical and chemical environmental factors.The difference of soil animal community in three tea gardens was calculated by using NMDS,ANOSIM.Moreover,the relationship of soil animal community with soil environmental factors and heavy metal pollution index was analyzed using RDA and correlation analysis.The results showed that the number of individuals,taxa groups,species richness,and diversity index of soil animals in unpolluted tea gardens were significantly higher than those of contaminated tea gardens I and II,while the number of individuals,group numbers,and species richness of soil animals in polluted tea garden II were also significantly higher than that in the polluted tea garden I.Evenness index of soil animal community in the unpolluted tea garden was significantly higher than that in the polluted tea garden II.Soil organic matter was the main environmental factor affecting the distribution of soil animals(51.42%),followed by total nitrogen(9.08%),total phosphorus(11.21%),available phosphorus and total potassium(9.61%).It positively correlated with the number of individual and groups of soil animals.Further analysis found that heavy metals such as Ni,Cd,As,and Cu were the main pollution factors in tea gardens,which significantly reduced the soil organic matter(63.8%and 58.5%),total nitrogen(61.7%and 65%)and available phosphorous(55.9%and 8.8%)content in the tea gardens I and II.Ni,Cd and As were the main toxic factors that limited the distribution of soil animal communities in tea gardens,which explained 46.55%,14.14%,and 9.83%of the variation of soil animals,respectively.Heavy metal pollution reduced the availability of soil nutrients in tea gardens,and the heavy metal pollution index limited the growth of the number of individuals and groups of soil animals.The richness index,diversity index and dominance index of the soil animal community decreased as the increaseing degree of heavy metal pollution.