赣江流域河岸带外来入侵植物的调查分析

通过对赣江流域河岸带植物调查,发现该地有外来入侵植物17科27属31种,其中菊科最多有9种。对赣江流域河岸带入侵植物分布的分析显示:外来入侵植物发生在赣江全流域,上、中、下游河岸带植物群落中入侵植物的优势度无明显差异;河岸带植被类型对入侵植物的分布影响较大,草本群落和灌草群落中的入侵植物优势度明显高于乔木林群落;干扰对外来植物的入侵起到了积极作用,与无干扰方式下的群落相比入侵植物的优势度差异极显著,但干扰方式对入侵植物的分布无影响。     

Digging deep for diversity: riparian seed bank abundance and species richness in relation to burial depth

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The influence of leaf litter on zooplankton in floodplain wetlands: changes resulting from river regulation

1. The loss of input of leaf litter through clearing of riparian vegetation may result in significant changes to aquatic ecosystems. River red gums (Eucalyptus camaldulensis) surrounding floodplain wetlands in the Murray–Darling Basin, Australia, contribute large quantities of leaf litter, but the quality of this resource may change depending on the timing of inundation. 2. We used experimental mesocosms to test the hypotheses that zooplankton would have a greater abundance with an input of leaf litter and that fewer zooplankton would emerge from egg banks in cleared than forested wetlands. The experiment was carried out in summer/autumn and in spring to test a third hypothesis that zooplankton would respond to changes in the timing of wetland inundation as a result of river regulation. 3. In summer/autumn, leaf litter reduced zooplankton abundance by 89% at the beginning of the experiment through its influence on water quality. Only a few taxa (Polyarthra spp., Colurella spp. and the cladoceran Family Moinidae) responded positively to leaf litter when water quality improved later in the experiment, indicating a switch in the role of leaf litter from a non‐trophic to a trophic pathway. 4. In spring, microcrustaceans emerged in smaller numbers from sediment sourced from cleared compared to forested wetlands, reflecting different communities in these two wetland types and/or disturbances to the sediment that interfere with emergence. 5. Although leaf litter appears not to be an important resource for zooplankton in floodplain wetlands, riparian clearing may have lasting effects on future emerging zooplankton communities. Additionally, river regulation may have considerable impacts on the influence of leaf litter on zooplankton, which has implications for the management of floodplain river systems.     

Do riparian reserves support dung beetle biodiversity and ecosystem services in oil palm-dominated tropical landscapes?

Agricultural expansion and intensification are major threats to global biodiversity, ecological functions, and ecosystem services. The rapid expansion of oil palm in forested tropical landscapes is of particular concern given their high biodiversity. Identifying management approaches that maintain native species and associated ecological processes within oil palm plantations is therefore a priority. Riparian reserves are strips of forest retained alongside rivers in cultivated areas, primarily for their positive hydrological impact. However, they can also support a range of forest‐dependent species or ecosystem services. We surveyed communities of dung beetles and measured dung removal activity in an oil palm‐dominated landscape in Sabah, Malaysian Borneo. The species richness, diversity, and functional group richness of dung beetles in riparian reserves were significantly higher than in oil palm, but lower than in adjacent logged forests. The community composition of the riparian reserves was more similar to logged forest than oil palm. Despite the pronounced differences in biodiversity, we did not find significant differences in dung removal rates among land uses. We also found no evidence that riparian reserves enhance dung removal rates within surrounding oil palm. These results contrast previous studies showing positive relationships between dung beetle species richness and dung removal in tropical forests. We found weak but significant positive relationships between riparian reserve width and dung beetle diversity, and between reserve vegetation complexity and dung beetle abundance, suggesting that these features may increase the conservation value of riparian reserves. Synthesis and applications: The similarity between riparian reserves and logged forest demonstrates that retaining riparian reserves increases biodiversity within oil palm landscapes. However, the lack of correlation between dung beetle community characteristics and dung removal highlights the need for further research into spatial variation in biodiversity–ecosystem function relationships and how the results of such studies are affected by methodological choices.     

三岩藏族体质特征研究

三岩是西藏自治区贡觉县与四川省白玉县交界的金沙江峡谷区, 本文对三岩藏族活体的测量数据做了统计分析, 认为三岩藏族的体质特征为高身材、中头型、中鼻; 属于蒙古人种北亚类型, 他们的体质特征不仅与中国南方、北方的其他民族有明显的差别, 而且跟藏族的其他支系也有很大的差别。三岩藏族具有独特的体质特征。     

长白山溪流河岸带森林木本植物多样性沿海拔梯度分布规律

采用样带网格调查方法和α、β多样性指数分析方法,研究了长白山河岸带原始林和次生林群落木本植物多样性沿海拔梯度分布规律及其对采伐干扰的响应.结果表明：不同海拔区域河岸带原始林群落均由11～13个树种组成,其在群落中的地位随海拔升高而发生变化,阔叶树种优势地位逐步被针叶树种所取代,采伐干扰不仅改变了群落树种丰富度及其在群落中的地位,而且使针叶树种取代阔叶树种的趋势有所增强;河岸带原始林群落物种多样性沿海拔梯度呈现出中、低海拔区域相对较高且比较恒定(2.454～2.544),高海拔区域(2.250)下降的分布规律,采伐干扰改变了其沿海拔梯度分布格局(波动型),加大了不同海拔区域群落间的波动性(2.174～2.692);河岸带原始林群落树种沿海拔梯度的变动速率相对较低(1.5～3.5),且群落相似性较高(0.85～0.94),采伐干扰使次生林群落树种沿海拔梯度的变动幅度增大(0.5～6.0),群落相似性下降(0.68～0.91),但次生林群落沿海拔梯度分布仍具有较高连续性.     

生境破碎化对黑白仰鼻猴种群数量的影响

从1999年4月至2002年6月间,对黑白仰鼻猴种群的分布和生境状况进行了调查。与十年前的调查结果相比,本次调查新发现了4个猴群,但有5个以前存在的猴群已经消失,现存种群数量为13个猴群,总体数量约为1200─1700只。从西藏的芒康到云龙的龙马山,随着海拔的降低,猴群可利用的植被类型也随之多样化。但由于砍伐、放牧、开矿等因素的影响,猴群的适宜生境破碎化程度较高,连接猴群的生境走廊状况通常较差,多数猴群孤立分布,并且存在小种群问题,生境走廊的维护和恢复已成为该物种保护成功与否的关键。种群的总体数量下降了32%,其中4个猴群数量下降,4个猴群持平,1个猴群有所增长,5个猴群消失,这不容乐观的状况给我们的保护工作敲响了警钟。     

文峪河上游河岸林群落类型及其生态适应性

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