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61.
NAOMI E. DAVIS DENNIS J. O'DOWD PETER T. GREEN RALPH MAC NALLY 《Conservation biology》2008,22(5):1165-1176
Abstract: Biological invaders can reconfigure ecological networks in communities, which changes community structure, composition, and ecosystem function. We investigated whether impacts caused by the introduced yellow crazy ant (Anoplolepis gracilipes), a pantropical invader rapidly expanding its range, extend to higher‐order consumers by comparing counts, behaviors, and nesting success of endemic forest birds in ant‐invaded and uninvaded rainforest on Christmas Island (Indian Ocean). Point counts and direct behavioral observations showed that ant invasion altered abundances and behaviors of the bird species we examined: the Island Thrush (Turdus poliocephalus erythropleurus), Emerald Dove (Chalcophaps indica natalis), and Christmas Island White‐eye (Zosterops natalis). The thrush, which frequents the forest floor, altered its foraging and reproductive behaviors in ant‐invaded forest, where nest‐site location changed, and nest success and juvenile counts were lower. Counts of the dove, which forages exclusively on the forest floor, were 9–14 times lower in ant‐invaded forest. In contrast, counts and foraging success of the white‐eye, a generalist feeder in the understory and canopy, were higher in ant‐invaded forest, where mutualism between the ant and honeydew‐secreting scale insects increased the abundance of scale‐insect prey. These complex outcomes involved the interplay of direct interference by ants and altered resource availability and habitat structure caused indirectly by ant invasion. Ecological meltdown, rapidly unleashed by ant invasion, extended to these endemic forest birds and may affect key ecosystem processes, including seed dispersal. 相似文献
62.
Islands face similar challenges for sustainability as continental areas, but their geographic situation conditions their options for development. However, thanks to their clear geographic boundaries, they are an opportunity to think about sustainability in an integrated way. The objective of the study was to explore from a local (island) and regional (archipelago) perspective strategies for sustainability. ‘Participative foresight scenario mapping’ (PFSM) methodology was used to explore the sustainable future of a small island (Flores Island, Azores, Portugal). The need to acknowledge the limit to growth is a key finding of this article. But the research also allowed us to analyse in depth specific strategies that can be applied to different sectors of activity, the most important being to: improve the quality of local products, diversify the economy and increase self-sufficiency. PFSM succeeded in identifying key themes and facilitating debate around these subjects. These findings can inform sustainable development in other islands or territories sharing similar geographic characteristics. 相似文献
63.
为了解海南岛及邻近陆地拟细鲫(Aphyocypris normalis)的遗传分化和亲缘地理过程,采用线粒体细胞色素b(Cyt b)对9个种群共124个个体的遗传多样性和遗传分化进行评估,并探讨这一物种的亲缘地理结构及演化历史.结果显示,在1 140 bp的序列中,共检测到87个核苷酸变异位点,定义了34个单倍型.基于Cyt b序列构建的系统发育树结果将所有个体分成3个主要谱系(A、B、C),谱系A包括海南岛大部分种群和邻近陆地全部种群,昌化江全部个体形成独立的谱系B,谱系C则为海南岛万泉河上安乡全部个体,各谱系间的遗传分化指数较高(0.707 5-0.971 9).分化时间估算的结果表明,谱系C的分化时间为2.038百万年前,谱系B的分化时间为0.865百万年前.种群历史动态分析表明,绝大部分种群均没有发生种群扩张,且所有谱系在近期都发生过有效种群数量减小的事件.根据研究结果推测,海南岛内万泉河上安乡种群的分化主要是由于五指山鹦哥岭山脉的隆起而导致的,而海南岛内和邻近陆地大部分群体没有发生分化可能是由于更新世冰期期间,岛屿和邻近陆地之间的水系因海平面下降而发生连接,琼州海峡两岸的拟细鲫种群有机会发生基因交流.因此认为琼州海峡并未对拟细鲫的扩散起到物理阻隔作用,海南岛为拟细鲫这一物种的起源扩散中心.(图4表6参48) 相似文献
64.
《Environmental Communication: A Journal of Nature and Culture》2013,7(8):1041-1052
ABSTRACTThe Block Island Wind Farm (BIWF) is the first offshore wind farm in the United States. Using gatekeeping theory as a framework, this research analyzes local and regional/national newspaper coverage of the BIWF paying particular attention to the use of sources. The data suggest that the differences between newspaper source usage from 1 January 2008 to 1 July 2017 is minimal. However, business sources appeared more than any other group, including government sources, which is a new finding. The prevalence of business sources leads to important questions about the role of businesses in shaping narratives about community transitions to renewable energy systems. 相似文献
65.
崇明岛共有区系植物55科157属198种,区系组成复杂,地理成分多样,涵盖全部15个分布区类型,具有明显的热带-温带过渡性质,落叶树种占木本植物种类的90.5%,属于北亚热带常绿落叶阔叶混交林地带。群落外貌及属的相似性系数分析表明,崇明岛植物区系更接近江苏宜兴,而与临近的大金山岛和佘山差别略大。此外,岛上还有栽培植物和外来植物共235种,其中蔷薇科、菊科、禾本科、豆科、木犀科等科的种类较丰富,以加拿大一枝黄花、臭荠、刺果毛莨、一年蓬、空心莲子草、大米草、互花米草等对当地植被资源和生态系统的影响最大。崇明岛植物群落结构单一,缺乏灌木层,草本层多为广布杂草,其植被资源可以根据功能划分为江防海防林、湿地植被、道路绿化带、庭院景观林、游憩林、大田作物及经济林、水源涵养林等7大类,其中江防海防林及湿地植被是崇明岛植被生态系统的关键成分。提供了崇明岛新纪录野生及外来种子植物名录。 相似文献
66.
运用能值分析的理论和方法,以中国第三大岛崇明岛为研究对象,定量分析和评价了1980~2003年岛内“社会-经济-自然”复合生态系统的能值自给率、人均能值用量、能值密度、环境负荷率、人口承载量以及基于能值分析的可持续发展指数等多项指标的变化趋势,并将2003年的数据进行了国内外对比。针对崇明建设生态岛的目标,分析了崇明岛的优势和不足,为其可持续发展提出了对应的建议和措施。研究表明:虽然良好的生态环境提升了人民的生活质量,但由于缺乏经济和科技竞争力,崇明岛的发展水平处于全国平均水平,与所处的长三角地区整体发展水平相差较大。但岛屿系统现状良好,运行稳定、健康、有活力,可持续性高。未来崇明岛的发展应当合理权衡和协调绎济发展和环境保护的关系,维持系统的可持续性。 相似文献
67.
68.
Codfishes, the Gadiformes, are quite abundant in modern temperate and polar waters with a fossil record ranging back into
the Palaeogene. The oldest records are from the Danian and Selandian of Europe and South Australia. The bipolar distribution
early in their evolutionary history implies that their origin must have occurred quite early in the Palaeocene, or even in
the Late Cretaceous with subsequent rapid diversification. By the Eocene, gadiforms were highly abundant and widespread. With
the exception of gadiforms, no Eocene Antarctic teleostean group is present in the modern Antarctic fauna. Here, we review
the early evolution and diversification of gadiforms in general and of macrouroids in particular. We also describe the undoubtedly
oldest skeletal macrourid specimen with otoliths preserved in situ. It is the first definitive record of this group from the
Eocene of Antarctica filling a gap in its stratigraphic distribution. The fossil record of gadiforms in general and macrouroids
in particular indicates that the origin of both was in shallow shelf environments but with adaptations to deep-water settings
early in their evolution. While gadoids seemingly originated in the earliest Palaeogene and rapidly experienced a first major
radiation event in the eastern North Atlantic and/or North Sea Basin, macrouroids evolved in the Southern Ocean and migrated
northwards into the South Atlantic before the establishment of the circum-Antarctic current and subsequent isolation of the
Antarctic fish fauna. These two timely and regional separated adaptive radiation events in the Palaeogene gave rise to their
modern taxonomic diversity and global distribution. 相似文献
69.
本文依据生态学理论对海岛土地及土地系统生态功能进行了重新的认识,并探讨了海岛土地系统生态设计的依据、原则和模式.设计中强调以土地系统生态保护性功能为主体,以海岛土地系统高层次调合发展作为海岛建设的最终目标. 相似文献
70.
Yazvenko SB McDonald TL Blokhin SA Johnson SR Melton HR Newcomer MW Nielson R Wainwright PW 《Environmental monitoring and assessment》2007,134(1-3):93-106
Exxon Neftegas Limited, as operator of the Sakhalin-1 consortium, is developing oil and gas reserves on the continental shelf
off northeast Sakhalin Island, Russia. DalMorNefteGeofizika (DMNG) on behalf of the Sakhalin-1 consortium conducted a 3-D
seismic survey of the Odoptu license area during 17 August–9 September 2001. A portion of the primary feeding area of the
endangered western gray whale (Eschrichtius robustus) is located in the vicinity of the seismic survey. This paper presents data to assess whether western gray whale bottom feeding
activity, as indicated by visible mud plumes, was affected by seismic operations. The mitigation and monitoring program associated
with the seismic survey included aerial surveys during 19 July–19 November 2001. These aerial surveys documented the local
and regional distribution, abundance, and bottom feeding activity of western gray whales. Data on gray whale feeding activity
before, during and after the seismic survey were collected, with the whales assumed to be feeding on the benthos if mud plumes
were observed on the surface. The data were used to assess the influence of seismic survey and other factors (including environmental)
on feeding activity of western gray whales. A stepwise multiple regression analysis failed to find a statistically significant
effect (α = 0.05) of the seismic survey on frequency of occurrence of mud plumes of western gray whales used as a proxy to evaluate
bottom feeding activity in Piltun feeding area. The regression indicated that transect number (a proxy for water depth, related
to distance from shore) and swell height (a proxy for sea state) were the only variables that had a significant effect on
frequency of whale mud plumes. It is concluded that the 2001 seismic survey had no measurable effect (α = 0.05) on bottom feeding activity of western gray whales off Sakhalin Island.
M.W. Newcomer, deceased 相似文献