Stay with the flow: How macroinvertebrate communities recover during the rewetting phase in Alpine streams affected by an exceptional drought

Droughts are affecting an increasing number of lotic ecosystems worldwide due to the combined effects of climatic and anthropogenic pressures. Unlike naturally intermittent rivers, where the drying phase is a part of the annual flow regime, water scarcity in Alpine rivers represents a relatively recent phenomenon and, therefore, a major threat for the biodiversity of these lotic ecosystems. However, Alpine stream community response to drought is still poorly investigated. Here, we assess the recovery of macroinvertebrates in two Alpine streams after a supraseasonal drought. As water returned, a total of 10 sampling sessions were carried out, and temporal patterns in diversity, density, and taxonomic composition of benthic communities, as well as in the percentage of functional feeding groups, were investigated. We found that the resistance of invertebrate communities in Alpine streams is generally low: drought markedly reduced the diversity and density of macroinvertebrates. Conversely, our results suggest that the passive dispersal by drift from the upstream river sections seems the most probable mechanism promoting the post‐drought recovery. Nevertheless, this resilience ability appears to be stream specific and influenced by intrinsic stream characteristics, including the flow permanence and distance from the nearest upstream perennial reach. This work sheds light on the ecological consequences of droughts on macroinvertebrate communities. As flow intermittency in Alpine areas is expected to intensify under current global change scenarios, results of this study provide important information to predict changes in the taxonomic composition and diversity of macroinvertebrate communities.     

阳宗海浮游生物群落结构研究

采用生物多样性指数方法,对2013年阳宗海湖泊的浮游生物群落结构进行研究。结果表明,阳宗海湖泊共检出浮游植物7门39属,蓝藻门的拟鱼腥藻和泽丝藻为优势种群;浮游动物鉴定出33种,轮虫为优势种;浮游植物和浮游动物的香浓多样性指数在1.10~2.83之间,均匀度指数在0.37~0.88之间,属于中度污染,阳宗海湖泊已处于中营养状态,并有向富营养化过渡的趋势。     

GigaMatrix: an ultra high-throughput tool for accessing biodiversity

Recombinant approaches for tapping into the biodiversity present in nature for the discovery of novel enzymes and biosynthetic pathways can result in large gene libraries. Likewise, laboratory evolution techniques can result in large but potentially valuable libraries. Thorough screening of these libraries requires ultra high-throughput methods. The GigaMatrix^™ screening platform addresses this opportunity using reusable high-density plates with 100,000 to 1,000,000 through-hole wells in a microplate footprint. In addition to throughputs of over 10⁷ wells per day, the platform offers a significant reduction in reagent use and waste, has fully integrated automated “cherry picking,” and uses no complicated dispensing equipment. Wells containing putative hits from targeted fluorescent liquid phase assays are revealed by a fluorescent imaging system. Vision-guided robotics are utilized to recover hits by accessing individual 200 μm and smaller wells with a disposable sterile needle. The GigaMatrix platform has proven to be an effective and efficient tool for screening gene libraries for both discovery and evolution applications.     

珠三角基塘农业生态系统修复及其生物多样性提升策略研究——以佛山市鲤鱼沙万亩公园为例

我国当前耕地保护和高标准农田建设,未将生物多样性提供的生态系统服务纳入相应的考核指标,导致农业景观生物多样性丧失严重.本文以珠三角河网区典型的基塘农业——佛山市顺德区鲤鱼沙万亩公园为例,通过景观连接度分析法、样方调查等深入评价其生境构成、结构和品质,揭示农业生态系统在高强度村居和工业园建设、苗圃和坑塘为主的流转生产方式...     

东江河流生态评价及其修复方略

本文通过对大型无脊椎底栖动物状况的调查对东江河流水生态状况进行了分析,并在此基础上提出了生态修复方略。从上游到河口选12个点采集底栖动物样本,发现东江流域底栖动物生物多样性在上游和中游保持在较高水平,而到下游则迅速降低到零。对增江湾、西枝江牛轭湖等处的取样进行分析并探讨改善东江生态的方法。针对不同生态应力提出了3种生态修复方略:1.创造多样性的生物栖息地,开发和形成一系列类似增江湾那样的缓流滞流区,把已经隔离的牛轭湖和江边湖泊湿地重新与江水连通;2.调整大坝运用方式,采取大坝泄放的流量逐渐增加和减少的方式,给生物发出流速增大和降低的信号,使其得以准备和躲避;3.稳定岸坡、控制侵蚀、保护和发育河边植被。     

面向森林生态学研究的Web处理服务系统

森林是陆地生态系统的主体,森林生态保护与恢复是生态文明建设的重要组成部分.面对森林生态模型单机化、重复开发部署的现状,本文设计并实现一个面向森林生态学研究的Web处理服务系统.该系统根据开放地理空间信息联盟（Open Geospatial Consortium,OGC）制定的空间数据共享及互操作的接口规范,基于WebService技术,实现了面向森林生态学研究的多模型整合,并将模型计算结果进行展示,减少了重复开发和部署工作,提高了数据与服务的共享性.     

大型底栖无脊椎动物在河流健康评价中的发展趋势

现从河流健康的内涵出发,回顾河流健康评价指标的发展历史,通过分析单一生物指数、生物多样性指数以及生物完整性指数的研究进展,评述了大型底栖无脊椎动物作为生物监测工具在河流健康评价之中的重要作用。针对其存在的问题,从技术、方法等方面提出建议,并展望大型底栖无脊椎动物在河流健康评价中的发展趋势,力求为我国河流健康评价工作提供借鉴,以便能够更好的进行流域管理和生态修复。     

Chemical warfare and survival strategies in bacterial range expansions

Dispersal of species is a fundamental ecological process in the evolution and maintenance of biodiversity. Limited control over ecological parameters has hindered progress in understanding of what enables species to colonize new areas, as well as the importance of interspecies interactions. Such control is necessary to construct reliable mathematical models of ecosystems. In our work, we studied dispersal in the context of bacterial range expansions and identified the major determinants of species coexistence for a bacterial model system of three Escherichia coli strains (toxin-producing, sensitive and resistant). Genetic engineering allowed us to tune strain growth rates and to design different ecological scenarios (cyclic and hierarchical). We found that coexistence of all strains depended on three strongly interdependent factors: composition of inoculum, relative strain growth rates and effective toxin range. Robust agreement between our experiments and a thoroughly calibrated computational model enabled us to extrapolate these intricate interdependencies in terms of phenomenological biodiversity laws. Our mathematical analysis also suggested that cyclic dominance between strains is not a prerequisite for coexistence in competitive range expansions. Instead, robust three-strain coexistence required a balance between growth rates and either a reduced initial ratio of the toxin-producing strain, or a sufficiently short toxin range.     

Land use/cover dynamics and their effects in the Gerado catchment,northeastern Ethiopia

This paper analyses the land use/cover dynamics of land degradation through the interpretation of aerial photographs (1958 and 1980) and 2006 SPOT-5 satellite image of the Gerado catchment. Other, non-visual data were gathered from personal interview and focus group discussions conducted in 2010 and 2011 with local elders, farmers and development (agricultural extension) agents. The results identified the presence of cultivated and rural settlement land, shrubland, woodland, bare land, grassland, urban built up area and forest. Throughout the period 1958–2006, urban built-up area, forest and cultivated and rural settlement land expanded at an average rate of 6.85%, 1.85% and 0.14% per year at the expense of shrub, wood and grasslands, which declined by 0.77%, 0.21%, 0.65% per year, respectively. The land use/cover dynamics of 1958–2006 resulted in the reduction/loss of biodiversity, occurrence of high soil erosion and ramification of gullies. The triggers for these changes were population growth, land cultivation, expansion of farmland, inappropriate land management, civil war and fuel wood demand. These led to further land degradation and more food insecurity among many farming households. Land resources have to be used according to their suitability. Thus, the exposed and steep mountains of the area have to be protected from cultivation and should be re-afforested. The paper discusses other implications for management and policy formulation also.     

增进城市地区生物多样性——以新加坡模式为例

自 1963 年以来,新加坡开展实施了绿化计划,并经历了从“花园城市”到“花园中的亲生态城市”的演变。为了在新加坡实现生物多样性保护,国家公园局制定了自然保护蓝图,重点介绍该规划实施的关键是利用技术创新。新加坡城市生物多样性指数是一种评价生物多样性成效的自我评估工具,已在全球范围内的多个城市得到应用。