寒温带牧林交错区生境复杂度对啮齿类物种多样性的影响

采用铗日法对嫩江流域牧林交错区5个生境梯度中啮齿动物的多样性水平进行了研究,以探讨栖息地复杂程度对地面啮齿类物种多样性的影响.结果表明,黑线姬鼠、黑线仓鼠和大林姬鼠是嫩江流域牧林交错区中的优势种和常见种,不同物种在不同生境类型中呈明显的不均匀分布,反映了它们对不同生境的选择倾向性.同时,地面草本植物的覆盖度和丰富度对地面活动的小型哺乳动物的物种组成和群落结构具有较大的影响,啮齿动物的捕获率和生物量与草本植物的多样性水平呈现出显著的相关性关系,其物种丰富度随草本植物多样性指数的增加呈递增的趋势.此外,各生境中啮齿动物的物种多样性指数与草本植物多样性的相关关系并不显著,可能是因为灌丛区和林-灌交错区内大量的低矮灌丛与萌生丛改善了生境的隐蔽条件与食物资源,为更多物种的共存创造了良好的微环境,使得两生境中啮齿动物的物种多样性水平尤为突出.研究表明,小型啮齿动物的物种组成与栖息地的复杂程度有关,但地面植被对小型兽类生物量和物种多样性的影响力度并不是等同的,对地面小型兽类物种多样性影响的研究,统计生境复杂度或异质性时应考虑不同植被型/生境类型距地面的高度,不同植被型对小型兽类物种多样性的贡献程度随其距地面高度的增加而降低.

Effects of habitat complexity on species diversity of small mammals in pastures and forest interlaced regions

Small mammals were trapped using snap-traps in five different pasture and forest regions to investigate the effect of habitat complexity on species diversity of small mammals. In total, 128 individuals were captured, comprising seven species of rodents, of which, Apodemus agrarius was the most commonly. The captured species were not evenly distributed along habitat gradients, which reflected the selection orientation of small mammals to different habitats. Analyses of richness and diversity of small mammals showed that trapping success, species richness and biomass of small mammals have a significant positive correlation with the diversity or heterogeneity of herbage but not with the whole vegetation heterogeneity. This indicated that the coverage and richness of herbage have a higher influence on the spatial distribution and community structure of small mammals. However, the diversity of small mammals had no similar relationships with the diversity or heterogeneity of herbage. Large quantities of small thickets in shrub and forest-shrub regions enhanced the diversity of small mammals. We concluded that the composition of small mammals is related to the complexity of habitats, while the effect of each vegetation type to the biomass and diversity of small mammals is not equal. The influence of herbage on small mammals is largest, while that of shrubs is the second, and trees has the smallest contribution, sometimes even a negative influence on the diversity of small mammals.