古尔班通古特沙漠植物分布的中域特征

探讨物种丰富度格局的中域特征是宏观生态学和保护生物学研究的热点问题,本文以具有代表性的温带沙漠-古尔班通古特沙漠南部为研究区域,结合调查实测的植物物种丰富度数据及样地间等距插值数据,分析了该区物种多样性分别沿纬向方向和经向方向上分布特点,探讨沙漠植物丰富度和密度格局的中域特征。结果显示,植物物种丰富度和密度格局在纬向和经向方向上形成不同的分布格局,中域特征不明显。在纬向方向上,呈现右半边驼形峰的格局模式,随着纬度的增加,物种丰富度和密度格局呈下降趋势;在经向方向上,分布格局呈现单调递增的趋势,但是趋势不明显。综合研究出现此现象的原因,认为本研究区尺度较小,纬向跨度为1.5°,经向跨度为4.5°,物种多样性受边界生境强烈影响。在纬向方向上,物种多样性受到绿洲小气候的影响,靠近绿洲地区的物种多样性较远离绿洲边缘的区域丰富度高;而在经向方向上,由西向东海拔逐渐增高,在降水随之增加影响下形成了物种多样性单向梯度变化,未能形成单峰的中域格局。由此可知,古尔班通古特沙漠研究区过小,植物多样性的中域特性不明显,在干旱区中域特征同样表现在大尺度上。     

青藏高原青南地区植物群落生态梯度分析

依据对青藏高原青南地区26个群落的样地调查和环境因子原始数据，用主分量分析(PCA)排序技术和回归模型，定量分析植物群落在空间的分布格局，以及群落结构特征和环境梯度之间的关系．结果表明：植物群落的类型分布主要决定于地理位置驱动下的水热条件，其次还受制于土壤养分．代表植物群落结构特征的生物多样性和丰富度分别与环境梯度有显著的相关性，随年均温和年降水量减少，群落物种多样性和丰富度有降低的趋势．     

Ecology: diversity and stability in plant communities

The relationship between species diversity and ecosystem stability is controversial. Tilman et al. analyse biomass patterns over a decade in a grassland experiment with artificial plant communities, and provide evidence for a positive relationship between the number of plant species and the temporal stability of the ecosystem. Here we use data from a long-term biodiversity experiment with plant communities that were not controlled by weeding in order to show that diverse systems can be both stable and unstable.     

Resource-use efficiency and plant invasion in low-resource systems

No species can maximize growth, reproduction and competitive ability across all environments, so the success of invasive species is habitat-dependent. Nutrient-rich habitats often experience more invasion than resource-poor habitats, a pattern consistent with traits generally associated with successful invaders (high growth rates, early reproduction and many offspring). However, invaders do colonize resource-poor environments, and the mechanisms that allow their success in these systems are poorly understood. Traits associated with resource conservation are widespread among species adapted to resource-poor environments, and invasive species may succeed in low-resource environments by employing resource conservation traits such as high resource-use efficiency (RUE; carbon assimilation per unit of resource). We investigated RUE in invasive and native species from three habitats in Hawaii where light, water or nutrient availability was limiting to plant growth. Here we show that across multiple growth forms and broad taxonomic diversity invasive species were generally more efficient than native species at using limiting resources on short timescales and were similarly efficient when RUE measures were integrated over leaf lifespans. Our data challenge the idea that native species generally outperform invasive species under conditions of low resource availability, and suggest that managing resource levels is not always an effective strategy for invasive species control.     

新疆喀依纳尔——青(羊居)(羊吕)山荒漠草原地带啮齿动物调查

本文报道了新疆喀依纳尔——青(羊居)(羊吕)山荒漠草原地带啮齿动物的的种属组成、啮齿动物群落与栖息生境的关系、繁殖情况以及动物地理分布的资料。     

贺兰山西坡植物多样性研究

研究了贺兰山西坡浅山带植物多样性特征.结果表明,不同植被带的植物多样性明显不同,荒漠灌丛带的物种丰富度、多样性和均匀度指数均随海拔的升高而增加;荒漠草原带的物种丰富度随海拔的升高呈现先增加而后降低的特点,其多样性和均匀度则随海拔的升高呈现先降低而后增加的趋势;疏林灌丛带的丰富度、多样性和均匀度指数随海拔的升高先增加而后基本保持不变.     

乌金山植物群落物种多样性的垂直分布格局

在乌金山适合地段沿海拔梯度设置11个样地,采用数量分类,对乌金山植物群落类型、物种组成和物种多样性的垂直分布格局进行调查.结果表明：（1）随着海拔的升高,森林群落依次为油松林、侧柏林、油松侧柏混交林、油松山桃山杏混交林、白皮松林、油松白皮松混交林.（2）11个样地中共调查到乔木13种,灌木16种,草本31种.（3）物种丰富度成明显的单峰分布格局,最大的丰富度出现在中海拔群落中.木本植物的物种丰富度随着海拔高度的增加而下降,草本植物的物种丰富度随着海拔高度的增加先增加后下降.（4）沿海拔梯度森林群落的最大树高、最大胸径、平均树高和平均胸径等群落结构均呈单峰分布格局.（5）α多样性沿海拔梯度变化趋势与物种丰富度相似,但没后者明显.β多样性随海拔的升高而有所降低,在低海拔较高.（6）在调查的海拔范围内,海拔梯度是影响植物群落分布的主要因子,坡度坡向为次要因子,海拔比坡度坡向对群落的结构特征、物种丰富度以及（α、β）多样性的影响更大,而在局部尺度上,人为干扰以及小地形导致的生境异质性对群落物种多样性有着重要影响.     

Global environmental controls of diversity in large herbivores

Large mammalian herbivores occupy half of the earth's land surface and are important both ecologically and economically, but their diversity is threatened by human activities. We investigated how the diversity of large herbivores changes across gradients of global precipitation and soil fertility. Here we show that more plant-available moisture reduces the nutrient content of plants but increases productivity, whereas more plant-available nutrients increase both of these factors. Because larger herbivore species tolerate lower plant nutrient content but require greater plant abundance, the highest potential herbivore diversity should occur in locations with intermediate moisture and high nutrients. These areas are dry enough to yield high quality plants and support smaller herbivores, but productive enough to support larger herbivores. These predictions fit with observed patterns of body size and diversity for large mammalian herbivores in North America, Africa and Australia, and yield a global map of regions with potentially high herbivore diversity. Thus, gradients of precipitation, temperature and soil fertility might explain the global distribution of large herbivore diversity and help to identify crucial areas for conservation and restoration.     

黄河三角洲土壤动物群落多样性和相似性

本文对黄河三角洲土壤动物群落多样性和相似性进行系统分析,探讨成土年限、植被类型对土壤动物群落演替的影响．研究结果表明,黄河三角洲土壤环境条件恶劣,土壤动物种类贫乏,且优势类群明显,群落异质性差,土壤动物群落的多样性较低,多样性指数不及最大多样性指数的二分之一．农田生态系统则因为人类的活动而改善了土壤环境,土壤动物的种类和数量均有所增加,多样性较高．11个样点、3个年代三角洲或6种植被类型之间土壤动物群落相似性较高,土壤含盐量是影响土壤动物最为重要的环境因子．随成土年限或植物群落演替,土壤动物群落在较高分类阶元上未能表现出明显的演替过程,有必要对土壤动物的分类进一步细化．     

云南寻甸石漠化土壤易氧化碳对丛枝菌根真菌共生的响应

【目的】运用菌根技术改良石漠化土壤性状,已成为石漠化地区植被与土壤恢复的重要生物学途径。揭示丛枝菌根(AM)真菌与植物共生驱动下石漠化土壤碳库及养分状况的变化,探明石漠化土壤易氧化碳(ROC)对土壤碳库及养分变化的响应过程及机制,为石漠化土壤的微生物修复及提高石漠化治理效率提供参考。【方法】采集云南昆明寻甸石漠化土壤,以尼泊尔桤木(Alnus nepalensis)为寄主植物,分别接种摩西斗管囊霉(Funneliformis mosseae, FM)、幼套近明球囊霉(Claroideoglomus etunicatum, CE)、根内根孢囊霉(Rhizophagus intraradices, RI),并设置对照处理(无寄主植物及无AM接种),采用高锰酸钾氧化法测定不同试验处理下土壤ROC含量,探究土壤ROC与碳库组成、养分状况及植物生长之间的相互关系。【结果】不同AM真菌均具有显著的侵染与促生效应,其中RI的侵染率与菌丝侵染密度最大,相较于对照分别提高155%和100%,并显著促进桤木树高(60%)与基径(46%)生长;不同AM真菌均显著提高ROC含量,3菌种对ROC含量的提升率大小顺序为:RI(122%)> CE(78%)> FM(61%)。ROC在土壤总有机碳库中所占比例(52%)远高于微生物生物量碳(3%~6%);3种菌种对土壤养分含量的提升效应表现为:RI > CE > FM。相较于对照,RI 菌种对植物可利用性氮、微生物生物量碳、总有机碳及植物可利用性磷的提升率分别为161%、127%、110%及97%;对ROC变化具有较大贡献的土壤环境因子分别为AM真菌侵染率(96%)、植物可利用性氮(94%)、微生物生物量碳(85%)、总有机碳(78%)及植物可利用性磷(72%)。【结论】AM真菌与尼泊尔桤木共生,显著驱动石漠化土壤碳库与养分含量变化并促进植物生长,进而增加石漠化土壤易氧化碳的积累。研究结果有助于理解石漠化地区植物生长、土壤恢复及活性有机碳沉积的微生物学调控机制。     

内蒙古温带草地低级根生物量格局及其与环境因子的关系

为了揭示根系生长策略与环境的关系以及草地植物根系周转对土壤碳的贡献, 在内蒙古荒漠草地、典型草地以及草甸草地设置17 个样点, 分析总根生物量、低级根生物量和低级根占总根生物量之比随草地类型与土层深度的变化及其与气候、土壤因素之间的关系。结果表明: 1) 低级根生物量与总根生物量正相关, 低级根生物量和总根生物量都与年均降水量、土壤氮含量正相关, 与年均温为负相关; 2) 低级根占总根生物量之比总体上呈现荒漠草原(14%)<典型草原(20%)<草甸草原(39%)的趋势, 与年均降水量正相关, 与年均温负相关, 与土壤全碳和全氮不相关; 3) 低级根生物量随土层的垂直分布规律与总根生物量一致, 在草甸草地随着土层加深而降低, 低级根主要分布在0~40 cm 表层土壤中(85%以上), 而在典型草地与荒漠草地则土层之间差异不显著。研究得到以下结论: 1) 草地植物根系可能通过不同机制响应温度和降水这两个环境因子; 2) 植物在水分贫乏的生境中可能通过降低对快速周转的低级根的投入来减少碳支出, 而投入更多的高级根来存储水分养分, 同时表明干旱生境中植物细根的水分养分吸收效率可能高于湿润生境。     

宁夏贺兰山蛾类区系调查及多样性分析

通过调查,共获得贺兰山自然保护区蛾类标本7 000余号.已鉴定的种类为15科144属186种,夜蛾科的种数最多,其次是螟蛾科、尺蛾科和卷蛾科.区系分析结果表明,贺兰山自然保护区蛾类以古北种为主,表明其具有很强的古北区特征,广布种次之,东洋种最少.根据中国地理区划,贺兰山蛾类除了自身的蒙新区特点外,与东北区、华北区联系最为密切.4个生境的多样性指数H′由大到小依次为山麓荒漠化草原、山前草原化荒漠、针叶林层、山地草原;均匀度指数J′由大到小依次为山麓荒漠化草原、山地草原、山前草原化荒漠、针叶林层;优势集中性指数C由大到小依次为山地草原、山麓荒漠化草原、针叶林层、山前草原化荒漠.     

纳木错流域自然生态特征与生物资源保护研究

在对西藏纳木错流域的自然生态进行实地考察的基础上,将该流域土壤类型划分为8类,主要植物群落确定为4个植被型10个群系.野生动物区系属于青藏区羌塘高原亚区.本区动物组成为古北界成分,其中珍稀保护动物16种.该文还对纳木错动物的地理分布特征和资源的保护利用提出了评价.     

Elevational patterns and determinants of plant diversity in the Baekdudaegan Mountains, South Korea: Species vs. functional diversity

The elevational gradient present in mountainous areas provides the most powerful natural experimental system available to clarify the ecological and evolutionary responses of living organisms to geophysical influences. In this study, we explored the elevational patterns of plant species and functional diversity and the effects of area, mid-domain effect, climatic variables and net primary productivity on the observed diversity patterns along the ridge of the Baekdudaegan Mountains, South Korea. Rapoport’s elevational rule was also evaluated by examining the relationship between elevational range size of plant species and elevation. A total of 802 plant species from 97 families and 342 genera were found in 1100 plots along a 200–-1900-m elevational gradient along the ridge. The elevational patterns of plant species diversity along the ridge of the Baekdudaegan depicted distinctly hump-shaped patterns, whereas the functional diversity decreased monotonically with elevation. The mid-domain effect was the most powerful explanatory variable for species diversity patterns. However, climatic variables were better predictors for functional diversity. Moreover, Rapoport’s elevational rule was not supported. Our study suggests that different elevational patterns may be observed among different diversity measurements even in the same taxon and that there may be fundamental differences in the mechanisms underlying these diversity patterns.     

Consumer versus resource control of species diversity and ecosystem functioning

A key question in ecology is which factors control species diversity in a community. Two largely separate groups of ecologists have emphasized the importance of productivity or resource supply, and consumers or physical disturbance, respectively. These variables show unimodal relationships with diversity when manipulated in isolation. Recent multivariate models, however, predict that these factors interact, such that the disturbance diversity relationship depends on productivity, and vice versa. We tested these models in marine food webs, using field manipulations of nutrient resources and consumer pressure on rocky shores of contrasting productivity. Here we show that the effects of consumers and nutrients on diversity consistently depend on each other, and that the direction of their effects and peak diversity shift between sites of low and high productivity. Factorial meta-analysis of published experiments confirms these results across widely varying aquatic communities. Furthermore, our experiments demonstrate that these patterns extend to important ecosystem functions such as carbon storage and nitrogen retention. This suggests that human impacts on nutrient supply and food-web structure have strong and interdependent effects on species diversity and ecosystem functioning, and must therefore be managed together.     

Resource-based niches provide a basis for plant species diversity and dominance in arctic tundra.

Ecologists have long been intrigued by the ways co-occurring species divide limiting resources. Such resource partitioning, or niche differentiation, may promote species diversity by reducing competition. Although resource partitioning is an important determinant of species diversity and composition in animal communities, its importance in structuring plant communities has been difficult to resolve. This is due mainly to difficulties in studying how plants compete for below-ground resources. Here we provide evidence from a 15N-tracer field experiment showing that plant species in a nitrogen-limited, arctic tundra community were differentiated in timing, depth and chemical form of nitrogen uptake, and that species dominance was strongly correlated with uptake of the most available soil nitrogen forms. That is, the most productive species used the most abundant nitrogen forms, and less productive species used less abundant forms. To our knowledge, this is the first documentation that the composition of a plant community is related to partitioning of differentially available forms of a single limiting resource.     

Ecosystem-level patterns of primary productivity and herbivory in terrestrial habitats

Ecosystems are structurally organized as food webs within which energy is transmitted between trophic levels and dissipated into the environment. Energy flow between two trophic levels is given by the amount of production at the lower level and by the proportion of production that is consumed, assimilated and respired at the higher level. Considerable evidence indicates that food-web structure varies predictably in different habitats, but much less is known about quantitative relationships among food web fluxes. Many of the energetic properties of herbivores in African game parks are associated with rainfall and, by inference, with net primary productivity. Respiratory costs per unit production at the consumer trophic level are higher for homeotherms than for heterotherms. Plant secondary chemicals affect herbivore dietary choices and the allocation of plant resources to those chemicals varies with resource availability. How these phenomena are translated into ecosystem fluxes is unknown. We present evidence that herbivore biomass, consumption and productivity are closely correlated with plant productivity, suggesting that the latter is a principal integrator and indicator of functional processes in food webs.     

啮齿类实验动物垫料的研究进展

实验动物垫料是实验动物饲养过程中非常重要的环境因素,直接影响实验动物的质量、动物福利及实验结果。本文就啮齿类实验动物垫料的种类、质量控制、物理性状、应用一季对啮齿类实验动物和动物实验的影响等方面进行了论述和总结,特别介绍了各种垫料的优缺点,对实际应用中选择和使用实验动物垫料提供了参考依据,有利于啮齿类实验动物垫料的研发和完善实验动物垫料等相关工作的进展。     

内蒙古中部农牧交错区中小型土壤动物群落特征研究

在内蒙古中部农牧交错区选择农田、退耕地、人工林地和荒漠草原4种生境类型，对中小型土壤动物群落特征进行了研究．结果表明，农牧交错区中小型土壤动物优势类群为线虫(Namatoda)，常见类群为螨类(Acarina)和弹尾类(Collembola)．从4种生境中小型土壤动物群落特征的对比分析看，退耕地的丰富度较高，多样性较大，荒漠草原的各种指数相对较低．从中小型土壤动物的垂直分布看，个体数和类群数随土层深度增加而递减，表聚性明显．不同生境中小型土壤动物个体数和类群数随季节变化具有一定的差异性．春季，人工林地个体数较多，退耕地个体数较少，农田类群数较多．夏季，农田个体数较多，荒漠草原个体数较少，退耕地类群数较多．秋季，人工林地个体数较多．农田个体数较少．人工林地类群数较多，退耕地类群数较少．     

Species diversity enhances ecosystem functioning through interspecific facilitation.

Facilitation between species is thought to be a key mechanism by which biodiversity affects the rates of resource use that govern the efficiency and productivity of ecosystems; however, there is no direct empirical evidence to support this hypothesis. Here we show that increasing the species diversity of a functional group of aquatic organisms induces facilitative interactions, leading to non-additive changes in resource consumption. We increased the richness and evenness of suspension-feeding caddisfly larvae (Insecta, Trichoptera) in stream mesocosms and found that the increased topographical complexity of the benthic habitat alters patterns of near-bed flow such that the feeding success of individuals is enhanced. Species diversity reduces 'current shading' (that is, the deceleration of flow from upstream to downstream neighbours), allowing diverse assemblages to capture a greater fraction of suspended resources than is caught by any species monoculture. The fundamental nature of this form of hydrodynamic facilitation suggests that it is broadly applicable to freshwater and marine habitats; in addition, it has several analogues in terrestrial ecosystems where fluxes of energy and matter can be influenced by biophysical complexity. Thus, changes in species diversity may alter the probability of positive species interactions, resulting in disproportionately large changes in the functioning of ecosystems.