生境差异和人类活动对云南剑川甸南镇小型哺乳动物群落结构和多样性的影响

小型哺乳动物的群落结构可反映当地生境质量, 为生态保护提供数据支撑。为了解生境差异和人为干扰对云南省剑川县甸南镇小型哺乳动物群落结构以及多样性的影响, 本文于2005年1月至2017年12月, 选择4种典型生境(菜园地、耕地、灌丛和住家附近), 采用笼捕法对小型哺乳动物展开调查。共布设鼠笼195,612个, 捕获小型哺乳动物16,060只, 隶属4目7科22种。其中啮齿目捕获到3科15种15,777只, 大绒鼠(Eothenomys miletus)和高山姬鼠(Apodemus chevrieri)为甸南镇优势种。不同生境间小型哺乳动物数量差异极显著, 数量最多的是灌丛, 共5,760只; 最少的是住家附近, 仅2,160只。菜园地的Shannon-Wiener多样性指数最高(1.26), 住家附近最低(1.08)。菜园地和耕地的物种相似性系数最高, 为0.94。本研究结果表明, 小型哺乳动物的群落结构和多样性受生境差异和人类活动干扰影响: 植物资源少、人类活动干扰程度高的生境中多样性指数低; 环境条件好、人类活动干扰适度的生境中多样性指数较高; 食物资源较少、干扰较少的生境中(如灌丛)多样性指数略低。     

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.     

Ant Diversity and Abundance along an Elevational Gradient in the Philippines1

Ant communities were surveyed along an elevational gradient in the Philippines extending from lowland dipterocarp forest (250 m elevation) to mossy forest (1750 m). Standardized pitfall trapping in arboreal and terrestrial microhabitats at seven sites yielded 51 species. Collecting by hand at five of the sites yielded 48 species. The two methods produced substantially different assemblages, with only 22 species (29%) taken in common. Only a fraction of the total ant community appeared to be sampled at most of the sites. Measures of species richness and relative abundance peaked at mid-elevations and declined sharply with increasing elevation. Ants were extremely rare above 1500 m elevation. Arboreal ants were trapped much less frequently than terrestrial ants at all sites. Ant species that were abundant had broader elevational distributions than those that were less common, but most species were rare and occurred at only one or two sites. The elevational patterns for ants are largely the inverse of those documented for Philippine small mammals which reach their greatest diversity and abundance at high elevations where ants are rare. This suggests that the two groups may interact competitively. Some of the patterns observed or inferred from this study may apply to tropical ant communities in general, and are presented as series of testable hypotheses as a guide and stimulus for future research.     

千岛湖岛屿小型兽类群落的多样性

2007 年秋季和2008 年春季,选取千岛湖地区14 个岛屿和2 个半岛作为样地,采用夹夜法进行小型兽类群落组成调查。两季度共布夹20 400 个,捕获小型兽类1 141 只,隶属2 目3 科9 属13 种,啮齿目(Rodentia)鼠科(Muridae)10 种和仓鼠科(Cricetidae)1 种,食虫目(Insectivora)鼩鼱科(Soricidae)2 种。利用以上结果分析其群落多样性,结果显示:14 个岛屿小型兽类群落春、秋两季的多样性指数、均匀度指数和优势度指数均呈现极显著差异且优势种发生变化;对可能影响岛屿小型兽类群落多样性的岛屿面积、距最近陆地距离、距最近大岛距离和植物丰富度等因素进行逐步回归分析,发现只有植物丰富度对小型兽类群落的物种丰富度有显著影响;对16 个样地按照物种组成比进行聚类,许源半岛样地与14 个岛屿聚为一类,姚家半岛样地单独归为一类,相似性指数比较结果亦显示姚家半岛样地与其它样地的相似性指数偏低。结论:景观破碎化导致千岛湖岛屿小型兽类群落的稳定性下降,物种多样性季节变化强烈;随岛屿面积的增加,小型兽类物种丰富度并非总是增加的,而是出现反复,呈现明显的小岛效应;14 个岛屿的物种与许源半岛样地物种构成比接近,推断在水库未形成前属同一生境。     

Reasons for arboreality in wood mice Apodemus sylvaticus and Bank voles Myodes glareolus

Although it is broadly accepted that small mammals often climb trees, only few studies explore arboreality in woodland rodents systematically. Here, we investigate the three-dimensional habitat use of wood mice Apodemus sylvaticus and bank voles Myodes glareolus at three different sites in Wytham Woods, Oxfordshire, under varying environmental conditions. A total of 12 trapping sessions was carried out between March and September 2003 and 2004. During each session, 100 Longworth live-traps with shrew escape holes were set in a 25-point-grid for 3 succeeding nights. Each time, 50 traps were placed on the ground, and 50 in surrounding trees at heights of 30–250 cm. Wood mice were significantly more arboreal than bank voles, and male wood mice spent significantly more time in trees than did females. Arboreality in bank voles occurred only under high population densities and food shortage, and both species were significantly more arboreal in woodland with dense understorey. Thus we conclude that while arboreality is predominantly a result of inter- and intra-specific competition, of the two species we studied, only wood mice, being more agile, can afford to utilize trees without getting caught by predators, and that sex differences are due to male territoriality. Estimates of population sizes and distribution, as well as studies of inter-specific interactions and socio-spatial behaviour are presumed to be affected by these results, and are currently likely to underestimate rodent numbers considerably.     

Effects of disturbance caused by selective timber extraction on fish communities in Sabah, Malaysia

To examine the effects of selective timber extraction on fish communities in Sabah, Malaysia, quantitative samples of fishes were taken from thirteen streams running through undisturbed rainforest or through forest that had been selectively logged 3–18 years previously. Multivariate analysis (canonical discriminant analysis and cluster analysis) indicated that mesohabitats within streams (riffles and pools) and differences in stream size were more important in determining community structure than logging history. Riffles in streams running through logged or undisturbed forest were indistinguishable using relative biomass or abundance data, as were pools from small streams (approximate order 2). Fish communities from pools in larger streams showed some separation in multivariate space corresponding to a complex set of relative changes in abundance and/or biomass between species. However it was difficult to unambiguously assign such changes to logging regime alone. There appeared to be some differences in fish communities between streams in recently-logged (3–7 years) and old-logged (17–18 years) areas related to abundance or biomass of three cyprinids (Garra borneensis, Lobocheilos bo and Osteochilus chini). Only one species, Pangio mariarum, was not found in streams in logged forest, but it was only found at one location in undisturbed forest. A number of other species showed significant differences in abundance or biomass between sites but most of these were only present at some sites and in low abundance. Principal components analysis of habitat data showed that riffle sites were homogeneous whatever their logging history as were pools in unlogged large streams. Pools in logged large streams were significantly more heterogeneous but in a random rather than systematic manner. It is concluded that the type of selective logging practices used locally have low impact on fish communities through mechanisms of persistence and/or rapid recolonisation.