唐家河自然保护区大熊猫种群数量及栖息地的移动

本文根据大熊猫季节性活动规律特点,应用海拔高度路线调查法,全面收集唐家河自然保护区大熊猫的比较新鲜粪便,计获１２４个粪样材料,提取ＤＮＡ作ＤＮＡ指纹图,经微机检测,保护区有大熊猫３７只,个体数量与粪样采集量之比为１∶３３５１４,有６个家系,雌兽２１只,雄兽１６只。并搞清了保护区生态环境质量,箭竹遭受病虫害的程度,洪水对栖息地的影响,特别对引起大熊猫数量减少及栖息地移动等原因,作了较为详细的分析。     

Conjugation morphology of Zygogonium ericetorum (Zygnematophyceae,Charophyta) from a high alpine habitat

Reproductive characteristics are important for defining taxonomic groups of filamentous Zygnematophyceae, but they have not been fully observed in the genus Zygogonium. Specimens of Z. ericetorum previously studied and used to clarify the generic concept lacked fertile material, which was obtained recently. This study illustrates for the first time, using color light microscopic and fluorescence images, a consequent conjugation stage in Z. ericetorum, including completely developed zygospores and purple cytoplasmic residue content left outside the zygospores, similar to aplanospore formation. Structures confirmed earlier reports and provided new observation informative regarding phylogenetically relevant reproductive characters of Z. ericetorum.     

太湖湖滨生态修复区大型底栖动物群落结构及梯度分布

2010—2011年对太湖贡湖湾湖滨带生态修复区滨岸挺水植物带(Ⅰ)、湾相沉水植物带(Ⅱ)和堰外开敞水体(Ⅲ)3个滨岸生境梯度带的水质状况和底栖动物群落特征进行了研究。结果表明:调查共发现底栖动物13科18种,其中仅出现于1个生境梯度带的物种7个;在其余的11个物种中,有5个种群的密度在生境梯度带间存在显著差异;比较发现,按底栖动物摄食功能类群的相对比例,刮食者相对丰度在带Ⅰ最高,收集者在带Ⅱ最高,滤食者在带Ⅲ最高,不同生境梯度带间底栖动物的摄食功能类群构成存在显著差异。对底栖动物相对丰度和水环境参数的冗余分析显示,环节动物和昆虫与DO、NO3--N和PO43--P浓度正相关,软体动物则与NO3--N和PO43--P负相关,一些腹足类对低DO耐受能力较强,与NH4+-N和COD正相关。修复区3个梯度带水动力条件、水质状况和底质类型的差异性对底栖动物的分布有重要影响,形成了生活习性、摄食特征等显著不同的3个底栖动物群落。     

Patch Connectivity and Genetic Variation in Two Congeneric Grasshopper Species with Different Habitat Preferences

Two congeneric species of grasshopper, Stenobothrus lineatus and S. stigmaticus, are compared in an analysis of genetic structure relative to their observed mobility, and to the spatial structure of their habitat networks. The species differ in their habitat requirements, the latter being rarer and more restricted to isolated patches. We tested for different patch connectivity between the two species in an analysis of genetic variance (based on allozymes) under the assumption that, besides isolation, rarity influences the genetic parameters. Between the species we found no differences in genetic structure as estimated by F_ST; i.e., no isolation effects and no apparent differences between the species in the potential to move between habitat fragments on either a local or regional scale were found. However, the amount of genetic variation in the more widely distributed and less xerothermic S. lineatus was significantly higher than in S. stigmaticus. Some consistency with observed philopatry within patches was found (F_IS > 0), but we consider regular dispersal events of medium and especially long distance to cause the habitat linking. We conclude that the connectivity between occupied patches inferred by genetic analyses can seldom be derived from low observed life-time movements recorded by conventional marking studies. Consequences of applying observed relative to indirect dispersal estimates for the examination of grasshopper metapopulations are discussed.     

广西木论自然保护区铁榄群落主要乔木种群格局的分形特征

为了揭示种群空间分布特征随尺度的变化规律,探讨不同种群对空间资源的占据能力和生态适应能力及分形差异,采用计盒维数、信息维数和关联维数对木论自然保护区铁榄群落主要乔木种群格局特征进行了研究。结果表明,优势种铁榄（Sinosideroxylon pedunculatum）、东女贞（Ligustrum japonicum）、小栾树（Boniodendron minius）、稀有濒危种掌叶木（Handeliodendron bodinieri）、青檀（Pteroceltis tatarinowii）5个种群在相应的尺度具有明显的分形特征;计盒维数和信息维数大小顺序一致,均为：铁榄〉东女贞〉小栾树〉掌叶木〉青檀;在5个种群中,铁榄计盒维数为1．7763最大,接近2,对空间环境的占据能力最强,信息维数（1．7206）也最大,个体聚集强度强,在群落中处于绝对优势地位,青檀计盒维数（0．8316）和信息维数（0．8990）最小,对环境的占据利用能力弱,个体聚集程度整体较弱,在群落中处于伴生地位;在0．5～50m的尺度上,关联维数大小顺序为：铁榄（1．7314）〉东女贞（1．6688）〉小栾树（1．6050）〉青檀（0．7868）,而掌叶木只有在大的尺度上才出现关联,且关联较强。3个分形维数大小的不同组合,能够全面揭示不同种群格局特征和种群在群落中所处地位的差异。     

上海闵行区园林鸟类群落嵌套结构

城市中的园林绿地呈现斑块状分布,其栖息地特征与岛屿栖息地相似。2008年11月至2009年10月,对上海市闵行区内的7块城市绿地进行调查,记录雀形目鸟类的分布情况,并运用Nestedness temperature calculator软件,检验其群落结构是否符合嵌套结构。运用Arc GIS软件分析该地区的卫星图片,收集7块样地的面积、绿地盖度、水源距离和人为干扰程度等数据,结合实地调查所得到的数据,分析这一嵌套结构的形成原因和影响因素。结果显示：上海市闵行区城市绿地中的雀形目鸟类分布是显著的嵌套结构,园林面积、绿地面积和水源情况都对其嵌套结构有显著影响。但是与真正岛屿上存在的群落分布嵌套结构不同,人为干扰程度对这一结构也有非常明显的影响。基于上述结果可以看出,影响上海市园林鸟类的群落嵌套结构的主要原因是栖息地的结构和人为干扰程度。因此,建议在规划和建设城市公园和绿地时,应该偏重于面积较大,植被盖度和丰富度高,结构合理的园林,并且尽量减少人为干扰。     

High‐density areas for harbor porpoises (Phocoena phocoena) identified by satellite tracking

The population status of harbor porpoises has been of concern for several years, and the establishment of Marine Protected Areas (MPAs) has been suggested as a method to protect the harbor porpoise (Phocoena phocoena, Linneaus 1758) and other small cetaceans. In order to designate MPAs, high‐density areas for the species must be identified. Spatial distribution of small cetaceans is usually assessed from ship or aerial surveys. As a potentially more accurate alternative, this study examined the movements and area preferences of 64 harbor porpoises, satellite tagged between 1997 and 2007, in order to determine the distribution in the North Sea, the western Baltic, and the waters in between. Results show that harbor porpoises are not evenly distributed, but congregate in nine high‐density areas within the study area. Several of these areas are subject to significant seasonal variation. The study found no differences in the home range size of males and females, but immature harbor porpoises have larger home ranges than mature porpoises. The use of satellite telemetry for identifying areas of high harbor porpoise density can be of key importance when designating MPAs.     

Synchrony of Seed Dispersal, Hydrology and Local Climate in a Semi-arid River Reach in California

The temporal availability of propagules is a critical factor in sustaining pioneer riparian tree populations along snowmelt-driven rivers because seedling establishment is strongly linked to seasonal hydrology. River regulation in semi-arid regions threatens to decouple seed development and dispersal from the discharge regime to which they evolved. Using the lower Tuolumne River as a model system, we quantified and modeled propagule availability for Populus fremontii (POFR), Salix gooddingii (SAGO), and Salix exigua (SAEX), the tree and shrub species that dominate near-channel riparian stands in the San Joaquin Basin, CA. A degree-day model was fit to field data of seasonal seed density and local temperature from three sites in 2002–2004 to predict the onset of the peak dispersal period. To evaluate historical synchrony of seed dispersal and seasonal river hydrology, we compared peak spring runoff timing to modeled peak seed release periods for the last 75 years. The peak seed release period began on May 15 for POFR (range April 23–June 10), May 30 for SAGO (range May 19–June 11) and May 31 for SAEX (range May 8–June 30). Degree-day models for the onset of seed release reduced prediction error by 40–67% over day-of-year means; the models predicted best the interannual, versus site-to-site, variation in timing. The historical analysis suggests that POFR seed release coincided with peak runoff in almost all years, whereas SAGO and SAEX dispersal occurred during the spring flood recession. The degree-day modeling approach reduce uncertainty in dispersal timing and shows potential for guiding flow releases on regulated rivers to increase riparian tree recruitment at the lowest water cost.