论社团文化在高校校园文化中的生态学地位

新的大学管理体制下,学生社团在校园中的活动日益活跃,社团文化成为学生主动学习的优势教育资源,对大学生的人文素质养成具有重要的影响,本文从生态学角度阐述了社团文化在高校校园文化中的重要地位。

榕树在西双版纳热带雨林中的地位和综合利用价值

对榕树在热带雨林生态系统中的地位进行了研究和分析 ,并对聚果榕、鸡嗉果榕的成熟果实进行了成分分析。结果表明 :除糖、脂肪、蛋白质等营养成分外 ,聚果榕、鸡嗉果榕的榕果均含有丰富的矿质元素和多种人体必需氨基酸 ,维生素 C的含量特别丰富 ,分别为 0 .68mg· g-1和 0 .2 8mg· g-1。矿质元素中 ,以钾、钙、镁的含量最为丰富。榕果能为食果动物提供全面而均衡的营养成分 ,榕果具有数量多、产量高、一年四季均挂果的特点 ,是热带雨林生态系统食物链的重要组成部分。

Visualizing Patterns of Genetic Landscapes and Species Distribution of Taxus wallichiana(Taxaceae),Based on GIS and Ecological Niche Models

The Chinese yew（Taxus wallichiana）,which is widely distributed in the Himalayas and in southern China,is now on the edge of extinction.In order to understand the evolutionary processes that control the current diversity within this species at the genetic and ecological levels,its genetic patterns and range dynamics must first be identified and mapped.This knowledge can then be applied in the development of an effective conservation strategy.Based on molecular data obtained from 48 populations of T.wallichiana,we used GIS-based interpolation approach for the explicit visualization of patterns of genetic divergence and diversity,and a number of potential evolutionary hotspots have been specifically identified within the genetic landscape maps.Within the maps of genetic divergence and diversity,five areas of high inter-population genetic divergence and six areas of high intra-population genetic diversity have been highlighted in a number of separate mountain regions,and these evolutionary hotspots should have the priority to be protected.Furthermore,four geographical barriers have been identified： the eastern Himalayas,the Yunnan Plateau,the Hengduan Mountains and the Taiwan Strait.According to ecological niche modeling（ENM）,the populations of T.wallichiana within the Sino-Himalayan Forest floristic subkingdom experienced westward expansion from the periods of Last Inter-glacial to Last Glacial Maximum（LGM）.Following the LGM,the distribution range overall became reduced and fragmented.These findings challenge the classic mode of contraction-expansion in response to the last glaciation.In conclusion,our findings suggest that the changes in geographical landscapes and climate that occurred during the Quaternary resulted in current genetic landscape patterns.

Dominant roles but distinct effects of groundwater depth on regulating leaf and fine-root N,P and N:P ratios of plant communities

Aims As the determinant of water availability in drylands,groundwater plays a fundamental role in regulating vegetation distribution and ecosystem processes.Although considerable progress has been made over the past years in the relationship between environment stress and plant community-level traits,the potential influence of water stress induced by groundwater changes on plant community-level stoichiometry remains largely unclear.Here,we examined whether belowground and aboveground community-level stoichiometry responded differently to groundwater changes.Methods We measured nitrogen(N)and phosphorus(P)concentrations in plant leaves and fine-roots of 110 plots under a broad range of groundwater depths in a typical arid inland river basin.We examined the spatial patterns and drivers of community-level N:P stoichiometry in leaves and fine-roots.Important Findings Community-level leaf and fine-root N,P and N:P ratios were mainly determined by groundwater,vegetation types and species composition,among which groundwater played a dominant role.Groundwater indirectly regulated community-level N:P stoichiometry through affecting vegetation types and species composition.Vegetation types and species composition had significant direct influences on communitylevel N:P stoichiometry.Furthermore,groundwater depth had opposite influences on community-level leaf and fine-root N:P stoichiometry.Groundwater depth regulated vegetation types and further decreased leaf N,P but increased leaf N:P ratios and fine-root N.Groundwater depth had a positive indirect impact on fine-root P but a negative indirect impact on fine-root N:P ratios primarily by affecting species composition.Our findings indicate that groundwater rather than climate conditions effectively regulates community-level N:P stoichiometry,and below-and aboveground N:P stoichiometry has opposite responses to groundwater.

Comparative phylogeography and niche modeling for three species complexes of SE China （Paradoxornis spp., Pycnonotus spp., Spizixos spp.）

Contrasting multiple organisms with similar contemporary distributions, researchers can identify shared evolutionary patterns and provide historical context for community composition. We used three species complexes with overlapping distributions in Southeastern China and surrounding islands to explore the phylogeographic history of the region. Despite similar geographic distributions, genetic data revealed few congruent patterns, but all complexes displayed genetic divergence for Taiwan Residents populations. Additionally, niche modeling and divergence dating did not find support for diversification associated with the Last Glacial Maximum [Current Zoology 61 （5）： 943-950,2015].

Driving mechanisms of nitrogen transport and transformation in lacustrine wetlands

As an essential component of proteins and genetic material for all organisms, nitrogen(N) is one of the major limiting factors that control the dynamics, biodiversity and functioning of lacustrine wetlands, in which intensified N biogeochemical activities take place. Reactive N loaded into wetland ecosystems has been doubled due to various human activities, including industrial, agricultural activities and urbanization. The main driving mechanisms of N transport and transformation in lacustrine wetlands are categorized to pushing forces and pulling forces in this study. Geomorphology, wetland age, N concentrations, and temperature are the main pushing forces(passive forces); whereas water table variation, oxygen concentration, other elements availability, oxidation-reduction potential(Eh) and p H, and microorganisms are the predominant pulling forces(active forces). The direction and kinetic energy of reactions are determined by pulling forces and then are stimulated by pushing forces. These two types of forces are analyzed and discussed separately. Based on the analysis of driving mechanisms, possible solutions to wetland N pollutions are proposed at individual, regional and global scales, respectively. Additional research needs are addressed to obtain a thorough understanding of N transport and transformations in wetlands and to reduce detrimental impacts of excessive N on such fragile ecosystems.