江西三清山两栖纲动物多样性及其区系特征

研究记录了三清山两栖纲动物2目7科24种,是江西省两栖纲动物比较丰富的地区之一.研究结果表明,小棘蛙、九龙棘蛙是江西省的新纪录,无斑肥螈在江西省的分布得到了证实,树蛙科、姬蛙科和蛙科种类颇为丰富.棘胸蛙组3种均分布于三清山;黑斑侧褶蛙、泽蛙、花臭蛙、棘胸蛙和中华大蟾蜍为优势种群;垂直分布特点明显,低海拔物种数量较多,随海拔升高,物种数量减少.中国特有动物13种;虎纹蛙为中国国家Ⅱ级重点保护动物;中国物种红色名录易危(VU)物种4种,近危(NT)物种1种.区系组成上东洋界成分占据绝对优势,东洋界成分仅由华中区成分及华中华南区共有成分组成,没有华南区成分.华中区成分和本区中国特有种均属南中国型.南中国型在该区出现频率高达58.3%,表明该区仍为其优势分布区.     

银杏的复合经营对土壤动物多样性的影响

对江苏省东台林场5种不同经营模式,包括银杏(G)、银杏+小麦(GW)、银杏+油菜(GR)、小麦(W)和油菜(R)土壤动物多样性进行调查,以了解不同经营模式对土壤动物群落的影响。试验中每种模式设置10 m×10m样方,每个样方采用品字形取0~5 cm、≥5~10 cm、≥10~15 cm 3个层次的混合样,3月和6月共采集土壤样本90个,经Tullgren土壤动物分离漏斗分离并用75%酒精固定后获土壤动物7 069头,分属于5门9纲21类。通过对物种丰富度(S)、多样性指数(H)、均匀度指数(J)、相似度指数(Q)和密度-类群指数(IDG)5个多样性指数进行分析,结果表明不同经营模式的多样性指数存在显著差异,土壤动物的优势种群为弹尾目和蜱螨目。G、GW、GR的丰富度、均匀度、密度-类群指数都高于W和R模式,优势度指数较小。丰富度指数与密度-类群指数显著正相关,季节只对R模式的多样性指数存在显著影响。G与GW和GR模式的土壤动物群落相似性指数较大,与W和R模式的土壤动物群落相似性较小,W与R模式的相似性较小。试验表明,不同经营模式对土壤动物群落具有一定的影响,与纯农模式相比,银杏复合模式提高了土壤动物的多样性,优化了土壤环境。     

内蒙古草地土壤细菌生物多样性与 生产力的相关关系分析

以内蒙古草地土壤细菌为研究对象,在3个不同的空间尺度上采集土壤样品,探讨内蒙古草地土壤细菌群落生物多样性与生产力之间的关系.内蒙古草地土壤细菌物种丰富度很高,达到上千个实用分类单元(OTUs);分属14个门,其中放线菌、变形菌和酸杆菌相对多度之和达80%以上.细菌群落生物量(每克干土DNA条带数)介于2.91×108~4.28×109条·g-1.稀化处理后的细菌OTUs数目、香侬-威纳指数和辛普森指数分别为721.79~1 023.47、5.84~6.21和82.98~229.02.但是,土壤细菌群落的生物多样性与生产力之间并不存在显著的相关关系,并且该模式与地理尺度无关.该结果暗示着该地区土壤细菌可能是中性或者近中性共存.     

Soil microbial community diversity and driving mechanisms

To study the structure of soil microbial communities, DNA was extracted from different environmental soil samples, and 16S rDNA clone libraries were constructed. The diversity of these 16S libraries were analyzed with restriction fragment length polymorphism based on amplification ribosomal DNA restriction analysis (RFLP-ARDRA)method. The results reveal a high diversity of the soil microbial communities, and striking differences in community structure at different depths. In the surface soil environment, there is no dominant gene pattern, but in the subsurface samples some dominant gene patterns are much more common. With the increasing depth the preference dominance becomes more significant. A spatial isolation hypothesis is proposed to explain the different community structures at different soil depths. Microcosms are set to simulate competition between populations at different degrees of spatial isolation. These studies reveal that spatial isolation caused by low moisture affects the competitive interactions of the two populations. In the two-strain microcosm there is one dominant population at high moisture, and no dominance in very dry environments     

南京紫金山地区蜻蜓目昆虫区系及多样性

于2005至2007年对江苏南京紫金山地区的蜻蜒资源进行了调查,经过对采集标本的鉴定,初步确定南京紫金山地区蜻蜒目昆虫有30种,隶属8科24属,其中8种是江苏省新纪录.该地区蜻蜒目区系组成的特点是:广布种所占的比例较大,东洋种次之,古北种最少.     

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.     

若尔盖高寒草地微地形的土壤微生物群落多样性特征

结合坡面微地形变化,从土壤微生物群落多样性角度研究典型缓丘区不同坡位上土壤微生物群落特征,了解微地形生境下土壤微生物群落变化趋势. 研究结果表明,土壤微生物群落培养的平均颜色变化率（AWCD）增长曲线呈现中坡位>坡顶＞下坡位＞上坡位>坡底的规律,中坡位土壤微生物群落代谢活性最高,坡底土壤微生物群落对基质的利用能力最低;在土壤微生物多样性指数比较中发现,除McIntosh均一度指数变化不显著外,其余土壤微生物多样性指数在不同坡位上存在显著差异. 其中,中坡位的Shannon丰富度指数及Simpson优势度指数最大,显著高于坡底指数值（P<0.05）;对土壤微生物群落碳源利用特征分析,氨基酸类利用率变化明显大于其他碳源,而胺类及酚酸类的利用程度较低,表明氨基酸类是土壤微生物利用的主要碳源;通过主成分分析发现,不同坡位的土壤微生物群落对碳源利用具有选择性,糖类、 氨基酸类、 聚合物类及酚酸类是对土壤微生物群落功能多样性差异贡献较大的碳源.     

Pervasive density-dependent recruitment enhances seedling diversity in a tropical forest

Negative density-dependent recruitment of seedlings, that is, seeds of a given species are less likely to become established seedlings if the density of that species is high, has been proposed to be an important mechanism contributing to the extraordinary diversity of tropical tree communities because it can potentially prevent any particular species from usurping all available space, either in close proximity to seed sources or at relatively larger spatial scales. However, density-dependent recruitment does not necessarily enhance community diversity. Furthermore, although density-dependent effects have been found at some life stages in some species, no study has shown that density-dependent recruitment affects community diversity. Here we report the results of observations in a lowland, moist forest in the Republic of Panamá in which the species identities of 386,027 seeds that arrived at 200 seed traps were compared with the species identities of 13,068 seedlings that recruited into adjacent plots over a 4-year period. Across the 200 sites, recruit seedling diversity was significantly higher than seed diversity. Part of this difference was explained by interspecies differences in average recruitment success. Even after accounting for these differences, however, negative density-dependent recruitment contributes significantly to the increase in diversity from seeds to seedling recruits.     

Plant diversity enhances ecosystem responses to elevated CO2 and nitrogen deposition

Human actions are causing declines in plant biodiversity, increases in atmospheric CO2 concentrations and increases in nitrogen deposition; however, the interactive effects of these factors on ecosystem processes are unknown. Reduced biodiversity has raised numerous concerns, including the possibility that ecosystem functioning may be affected negatively, which might be particularly important in the face of other global changes. Here we present results of a grassland field experiment in Minnesota, USA, that tests the hypothesis that plant diversity and composition influence the enhancement of biomass and carbon acquisition in ecosystems subjected to elevated atmospheric CO2 concentrations and nitrogen deposition. The study experimentally controlled plant diversity (1, 4, 9 or 16 species), soil nitrogen (unamended versus deposition of 4 g of nitrogen per m2 per yr) and atmospheric CO2 concentrations using free-air CO2 enrichment (ambient, 368 micromol mol-1, versus elevated, 560 micromol mol-1). We found that the enhanced biomass accumulation in response to elevated levels of CO2 or nitrogen, or their combination, is less in species-poor than in species-rich assemblages.     

陕北枣林土壤动物与土壤因子关系研究

目的为深入研究枣林土壤动物对土壤质量变化的指示作用提供基础资料和理论依据。方法在陕北枣林研究区域内,以土壤动物和根际土壤为研究对象,采取野外调查取样、定点动态观测与室内实验测试相结合的研究方法。结果陕北枣林土壤动物类群数与土壤因子的相关程度不如密度明显。大型土壤动物类群数及其和中小型土壤动物密度与土壤营养要素相关程度较为密切,而且pH值无论对土壤动物类群数还是密度影响都最明显;土壤含水量对大型土壤动物的类群和中小型土壤动物密度有显著影响;陕北枣林土壤动物与土壤环境要素特征也具有明显的季节性变化。结论生境差异对大型土壤动物群落类群数均具极显著影响,而季节变化仅对中小型土壤动物个体密度具有显著影响。     

草原矿区苔藓植物多样性及其与土壤理化性质的关系

以内蒙古半干旱区草原的代表煤矿—胜利煤矿及周边的贝子庙、植物园、南山水库为研究区,通过对苔藓植物群落特征和土壤理化性质的相关性研究,分析了复垦过程中土壤对苔藓植物分布的影响.结果表明,胜利矿区苔藓植物有4科6属7种,各生境苔藓总盖度排序为贝子庙>植物园>矿区南排土场>水库>人工林>矿区北排土场.多样性指数分析结果表明,南排土场苔藓群落物种复杂程度高.对苔藓植物群落盖度与土壤理化性质的相关性分析表明,土壤pH值、粉粒含量、沙粒含量和石砾含量对苔藓植物的分布都有显著影响.通过对苔藓植物群落结构与土壤理化性质的多元分析,发现不同研究区苔藓植物群落结构的差异性与环境因子的综合影响有关.     

缙云山森林次生演替序列群落结构,物种多样性与稳定性关系

基于物种多样性导致稳定性理论,从层次结构和物种多种性指数方面着手,测度和分析了缙云山森林次生演替序列群落的物种多样性与稳定性关系．结果表明,随着群落稳定程度的增加,灌木层、乔木层个体数比例增大,而草本层比例则呈下降趋势;相对稳定的顶极群落,各层次的物种多样性指数（Ｈ）和均匀度指数（Ｊ）波动水平较小;不稳定的发展中群落,各层次的Ｈ和Ｊ波动水平较大,灌木层和草本层建立初期Ｈ和Ｊ较高,以后下降;而乔木层建立初期Ｈ和Ｊ较低,以后上升,最后各层次的Ｈ与Ｊ均趋向一致．测定方法上,认为物种多样性指数和均匀度指数比层次结构图更为有效．     

天然草地放牧绵羊的营养需要与草地供应

根据动物饲养标准,运用理论计算研究了放牧绵羊的营养需要和草地供应等家畜生产、草地管理问题.结果表明:天然草地放牧绵羊随日增重水平提高,达到期望生长量所需日数减少,所需能量和粗蛋白也逐渐减少;自由放养绵羊的日增重水平相当于舍饲饲养100 g的日增重水平,北方草地在自由放养的基础上,选择150～200 g的日增重水平进行设计饲养可以获得明显的经济效益和生态效益;每只羊每年补饲100 kg苜蓿和50 kg玉米秸秆可以满足设计饲养要求,实现当年生羔羊羯羊体重达到46 kg、胴体重21 kg的国际先进饲养水平.     

江河源地区不同荒漠化草地物种多样性研究

在江河源地区的高寒草甸、高寒草原中选择8个具有代表性的荒漠化草地进行物种多样性研究,其中对玉树州曲麻莱县郊、果洛州玛多县郊、果洛州达日县窝赛乡三个地区进行了不同演替梯度下的物种多样性分析。结果表明：曲玛莱地区退化草地物种多样性指数、均匀度指数随退化程度的加剧而减小,丰富度指数为重度退化大于极度退化大于轻度退化;玛多县郊、达日县窝塞乡重度退化草地物种多样性、均匀度、丰富度高于极度退化。不同荒漠化地区随演替度的减小多样性指数、均匀度指数总体有递减趋势,而丰富度指数变化不明显。     

山地垂直自然带的土地结构与演替理论

土地结构与演替是经过对土地类型的深入研究后提出的重要理论问题之一．本文以陕西秦巴山区为例，运用遥感技术、数理分析和计算机新技术，通过由ＧＩＳ支持的土地结构系统动力学仿真模拟与模型建立，在土地分类的基础上，从山地自然地理特点出发，对秦岭南、北坡和大巴山北坡的不同垂直带层的土地结构格局与演替模式做了理论研究．认为土地结构是土地所有属性的结合形式、联系方式与对比关系，他包括空间和功能有序两个方面；土地演替是土地结构与功能的自组织，这种自组织过程靠一定的地理过程来维持，是土地内部物流与能流转化迁移的结果，土地演替分为自然演替和人为演替两种过程．从而拓宽和纵深了土地研究的内容     

海滨无脊椎动物野外实习多媒体图文资料库的建立研究

利用微软公司的 Visual Fox Pro6.0中文版开发成一个多媒体图文资料库 ,以便在动物学野外实习过程中得到应用 .     

新乡市获嘉县传统耕作区农田土壤微生物群落结构和多样性研究

新乡地区是河南省重要的粮食产区,其农田土壤微生物的群落结构和多样性目前仍不清楚.以新乡市获嘉县长期免耕和传统耕作的农田土壤为材料,测定其土壤理化特征,并且采用高通量测序技术分析其土壤微生物的群落特征.结果显示,该区域农田土壤的基本理化性质为:含水量9.37%～13.39%,pH值8.55～8.65,全氮和全磷质量分数分别为0.91～0.96mg/g和4.06～5.34mg/g.土壤中优势细菌菌群为变形菌门(～30%)、浮霉菌门(～20%)、酸杆菌门(～16%)和放线菌门(～8%),优势真菌菌群为子囊菌门的粪壳菌纲(～50%)、散囊菌纲(3%～10%)和座囊菌纲(～10%).免耕处理的土壤微生物丰富度和多样性要高于常规耕作的土壤微生物,而且轮作处理的土壤微生物数量要高于同等条件下单一种植模式的对照处理.本研究有助于了解该地区不同种植模式下的土壤微生物群落结构,可为进一步改良土壤和防治土传病害提供理论依据.