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生物多样性是生物及其与环境形成的生态复合体以及与此相关的各种生态过程的总和。由于气候变化、人类活动的加剧,生物多样性正在经受前所未有的快速变化,各国政府和相关国际组织已经积极投入到生物多样性监测和保护中。为了解生物多样性的现状和变化规律,全球性、区域性及国家性生物多样性监测网络陆续建立。地球观测组织—生物多样性监测网络(GEO BON)作为全球性网络,目的是建立和完善生物多样性监测核心指标EBV(Essential Biodiversity Variables),推动监测指标的标准化和全球化,为数据共享和大尺度生物多样性变化评估奠定基础。在区域尺度上,欧盟成立了EU BON,亚太地区成立了AP-BON。在国家尺度上,瑞士、英国、日本等均建立了监测网络。中国科学院在"十二五"期间成立了中国生物多样性监测与研究网络(Sino BON),对中国生物多样性的变化开展长期的监测与研究。生物多样性监测依赖于传统调查方法与先进技术结合,如红外相机、基因技术、无人机技术等。遥感能够提供大范围、全覆盖的生物多样性信息,是未来大尺度生物多样性监测的重要手段之一。为此,GEO BON成立了"生态系统结构"组主要研究如何建立基于遥感数据的EBV。Sino BON也引入了无人机近地面遥感技术探讨更大区域的生物多样性监测。未来随着中国综合地球观测系统的完善,Sino BON的地面观测将更好地与卫星数据结合,实现生物多样性天地一体化监测,服务于中国生物多样性保护与评估。 相似文献
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Positive and negative interactions can occur simultaneously between plant species. According to the stress gradient hypothesis (SGH), species interactions shift towards more facilitative interactions or reductions in competition with increasing stress, whereas debate continues over whether evolutionary history influences the strength of species interactions. However, few studies have investigated the effects of phylogenetic relatedness (i.e., the sum of branch lengths separating species on a phylogeny) on the outcomes of interspecific interactions across stress levels. Therefore, we conducted a Bayesian meta-analysis on data collected from publications on plant interactions within coastal ecosystems in order to investigate the effects of phylogenetic relatedness on interspecific interactions across different stress levels. These analyses showed the effect sizes of species interactions on survival and growth to increase with stress increment, supporting the SGH in coastal ecosystems. However, phylogenetic relatedness did not lead to these differences of interspecific interactions between low and high stress. We found that species interactions affecting plant survival were not significantly influenced by phylogenetic relatedness; however, when evolutionary relationships of target and neighbor species were more phylogenetically distant, their interactions were more likely to facilitate growth of target species. Furthermore, the effect of the interaction between phylogenetic distance and stress on species interactions was negative. This suggests the observed net effects of phylogenetically distant neighbor species on target species were not due to true facilitation but reductions in competition when moving from low stress to high stress environments. According to these results, phylogenetic relatedness should be considered in choosing species for restoration of coastal ecosystem plant communities. Specifically, increasing the phylogenetic breadth of the assemblage is more likely to include species that have evolved to reduce stress on surrounding species through modification of the environment. 相似文献
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哈密黄山东铜镍矿床中几个罕见矿物 总被引：4，自引：0，他引：4
本文概略地介绍了哈密黄山东Ｃｕ－Ｎｉ矿床产出的地质条件，含矿岩体的Ｓ，Ｎｉ丰度值（Ｗ＿ｓ２８２３×１０￣（－６），Ｗ＿（Ｎｉ）８２９×１０￣（－６）），以及矿石中出现的有趣矿石组构；另外，对新发现的三个罕见矿物（叶碲铋矿、自然铅、锑硫镍矿）的光学性质和化学成分也作了介绍。根据几个罕见矿物的化学成分和矿石组构特征，文章讨论了黄山东Ｃｕ－Ｎｉ矿床的成矿物理化学条件。结论是不宜形成富矿。 相似文献
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Jie Xu Kedong Yin Joseph H. W. Lee Donald M. Anderson Yuelu Jiang Xiangcheng Yuan Alvin Y. T. Ho Paul J. Harrison 《Journal of Oceanography》2012,68(4):545-560
Hong Kong waters receive high nutrient loading from year-round sewage effluent and Pearl River discharge during the summer wet season. We assessed the role of physical processes in reducing eutrophication by calculating a eutrophication reduction index for four different hydrographical areas and four seasons. We used outdoor incubation experiments to assess the response of phytoplankton when physical (mixing and dilution) processes and mesozooplankton grazing were reduced. The primary regulator of phytoplankton growth in low nutrient eastern waters (reference site) shifted from nutrients in the wet season to increased vertical mixing in the dry season. In the highly flushed western waters and Victoria Harbour, the majority (>86?%) of the eutrophication impacts were reduced by strong hydrodynamic mixing (turbulence, vertical mixing, and flushing effects) all year. In southern waters, eutrophication effects were severe (chlorophyll a of up to ~73?μg?L?1) and was regulated by the ambient phosphate (PO4) concentration (~0.1?μM) during summer. In contrast, 62–96?% of the potential eutrophication impacts were reduced by physical processes during other seasons. Bioassays also revealed that the yield of chlorophyll from dissolved inorganic nitrogen (DIN) that was taken up by phytoplankton [1.1–3.3?g?Chl (mol?N)?1] was not significantly different in both N- and P-limited cases. In contrast, the uptake ratios of DIN:PO4 (26:1–105:1) and Chl:P ratios [42–150?g?Chl (mol?P)?1] in the P-limited cases were significantly (p?<?0.05, t test) higher than the N-limited cases [~16DIN:1P and 22–48?g?Chl (mol?P)?1]. The C:Chl ratios ranged from 32 to 87?g?g?1. These potential ranges in ratios need to be considered in future nutrient models. 相似文献