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191.
The Great Barrier Reef is an iconic ecosystem, known globally for its rich marine biodiversity that includes many thousands of tropical breeding seabirds. Despite indications of localized declines in some seabird species from as early as the mid-1990s, trends in seabird populations across the reef have never been quantified. With a long history of human impact and ongoing environmental change, seabirds are likely sentinels in this important ecosystem. Using 4 decades of monitoring data, we estimated site-specific trends for 9 seabird species from 32 islands and cays across the reef. Trends varied markedly among species and sites, but probable declines occurred at 45% of the 86 species-by-site combinations analyzed compared with increases at 14%. For 5 species, we combined site-specific trends into a multisite trend in scaled abundance, which revealed probable declines of Common Noddy (Anous stolidus), Sooty Tern (Onychoprion fuscatus), and Masked Booby (Sula dactylatra), but no long-term changes in the 2 most widely distributed species, Greater Crested Tern (Thalasseus bergii) and Brown Booby (Sula leucogaster). For Brown Booby, long-term stability largely resulted from increases at a single large colony on East Fairfax Island that offset declines at most other sites. Although growth of the Brown Booby population on East Fairfax points to the likely success of habitat restoration on the island, it also highlights a general vulnerability wherein large numbers of some species are concentrated at a small number of key sites. Identifying drivers of variation in population change across species and sites while ensuring long-term protection of key sites will be essential to securing the future of seabirds on the reef.  相似文献   
192.
Abstract: Ecological traps and other cases of apparently maladaptive habitat selection cast doubt on the relevance of density as an indicator of habitat quality. Nevertheless, the prevalence of these phenomena remains poorly known, and density may still reflect habitat quality in most systems. We examined the relationship between density and two other parameters of habitat quality in an open‐nesting passerine species: the Ovenbird (Seiurus aurocapilla). We hypothesized that the average individual bird makes a good decision when selecting its breeding territory and that territory spacing reflects site productivity or predation risk. Therefore, we predicted that density would be positively correlated with productivity (number of young fledged per unit area). Because individual performance is sensitive to events partly determined by chance, such as nest predation, we further predicted density would be weakly correlated or uncorrelated with the proportion of territories fledging young. We collected data in 23 study sites (25 ha each), 16 of which were located in untreated mature northern hardwood forest and seven in stands partially harvested (treated) 1–7 years prior to the survey. Density explained most of the variability in productivity (R2= 0.73), and there was no apparent decoupling between density and productivity in treated plots. In contrast, there was no significant relationship between density and the proportion of territories fledging ≥1 young over the entire breeding season. These results suggest that density reflects habitat quality at the plot scale in this study system. To our knowledge this is one of the few studies testing the value of territory density as an indicator of habitat quality in an open‐nesting bird species on the basis of a relatively large number of sizeable study plots.  相似文献   
193.
Abstract:  Ecosystem-scale networks of marine protected areas (MPAs) are important conservation tools, but their effectiveness is difficult to quantify in a time frame appropriate to species conservation because of uncertainties in the data available. The dugong ( Dugong dugon ) is a mobile marine species that occurs in shallow inshore waters of an ecosystem-scale network of MPAs (the Great Barrier Reef World Heritage Area [GBRWHA]). We developed a rapid approach to assess risk to dugongs in the region and evaluate options to ameliorate that risk. We used expert opinion and a Delphi technique to identify and rank 5 human factors with the potential to adversely affect dugongs and their sea grass habitats: netting, indigenous hunting, trawling, vessel traffic, and poor-quality terrestrial runoff. We then quantified and compared the distribution of these factors with a spatially explicit model of dugong distribution. We estimated that approximately 96% of habitat of high conservation value for dugongs in the GBRWHA is at low risk from human activities. Using a sensitivity analysis, we found that to decrease risk, commercial netting or indigenous hunting had to be reduced in remote areas and the effects of vessel traffic, terrestrial runoff, and commercial netting had to be reduced in urban areas. This approach enabled us to compare and rank risks so as to identify the most severe risks and locate specific sites that require further management attention.  相似文献   
194.
ABSTRACT

A transdisciplinary review of the current academic knowledge of Indigenous traditional fire management is presented for the Mt Lofty Ranges in South Australia. For a long time, the roles of Indigenous management of the landscape have either been overlooked or discounted within environmental studies. That situation is beginning to change in many parts of Australia. However, this review of knowledge of traditional Indigenous burning practices specifically for the Mt Lofty Ranges suggests that there is very little formalised, academic knowledge available that could be utilised to inform prescribed burning practices in the region. Perhaps Indigenous peoples’ use of fire was strongly governed by individual choices, or perhaps established regimes demarcated roles across groups; perhaps some areas were burnt regularly and others were left unaltered – there is still no clear evidence from the academic literature to provide even limited understandings of such elements of pre-colonial fire regimes. That gap in knowledge will become increasingly problematic as the need for appropriate, sophisticated burning practices to respond to risk in peri-urban Adelaide increases with a changing climate. To learn from traditional Indigenous land management: (a) formal knowledge needs to be generated on past regional burning practices; and (b) understanding needs to be developed as to whether past burning practices could lead to effective hazard management and biodiversity outcomes within contemporary landscapes. Such an integration of Indigenous knowledge for effective environmental management will only be possible if the injustices of past exclusions of the importance of Indigenous biocultural practices are recognised.  相似文献   
195.
本文研究了水中痕量铍的稳定性大小,与水中酸度、与水中存在的沉淀物种类及量以及与贮存容器有关,为了使标准溶液与水样中痕量铍不致因容器表壁吸附或沉淀物吸附而损失,经试验采用聚乙烯瓶盛装最好,并用盐酸或硝酸调至溶液酸度为pH1-2为好。  相似文献   
196.
Fluorinated compounds (FC) are high-global warming potential (GWP) greenhouse gases used and emitted during the manufacture of silicon semiconductor devices. Following the U.S. EPA's PFC Emissions Vintage Model (PEVM), uncontrolled FC emissions are modeled as proportional to total manufactured layer area (TMLA) of silicon. FC emissions of World Semiconductor Council (WSC) charter member countries (Europe, Japan, Korea, Taiwan and the United States), which voluntarily committed in 1999 to lower FC emissions by 2010 to 10% of baseline year emissions, are modeled for the period 1995–2020. For this same period, emissions from Chinese manufacturers under alternative emission reduction scenarios are modeled. If Chinese manufacturers were to adopt a baseline year of 2005 and a reduction target of 10% below baseline year emissions to be achieved by 2020, emissions would be 3.4 MMTCO2eq, comparable to the similarly projected controlled emissions of an average WSC charter member country (=16.3/5 MMTCO2eq) in 2020. The relative stringency of the alternative reduction scenarios considered for China vary between 50 and 95% reduction compared to business as usual (BAU). This is comparable to the stringency of the WSC charter members’ goals for which FC emission reduction technologies are currently available.  相似文献   
197.
江西生态环境现状与建设生态经济区的可行性分析   总被引:1,自引:1,他引:0  
江西具有比较封闭的生态环境系统,目前全省环境总体质量尚好,但局部地区污染仍较严重。同周边地区相比,江西总体经济发展比较滞后。要尽快改变这种状况、实现江西跨越式发展,进行生态经济区的建设是可行途径。从可持续发展的基本原理出发,对在江西生态环境现状进行评价后,分析了江西建设生态区的必要性、基础与条件、指出了应当重点关注的主要问题。  相似文献   
198.
皖浙赣交境地区南华纪地层划分与对比   总被引:1,自引:1,他引:0  
皖浙赣交境地区南华纪地层发育,出露面积广,属扬子地层区江南地层分布。因地层分区内不同地段的地层发育程度及沉积特征常有差异可进一步划分出皖浙赣地层小我和广丰地层小区。本文分别介绍了各地层小区的岩石地层单位特征、划分及对比,分析了该区不同时期的古沉积环境及岩相变化规律。  相似文献   
199.
成都市热力景观空间格局分析   总被引:1,自引:0,他引:1  
但尚铭  但玻  蒋薇 《四川环境》2011,30(2):53-56
城市热力景观空间格局是城市附属物和城市活动性在热场方面的综合表现。使用2008年11月23日的Landsat5/TM数据,将第6波段反演为亮温,并按温度值的高低把热力景观分为7个类型;借鉴景观生态学的原理和方法,以破碎度指数、多样性指数、均匀度指数和优势度指数为评价指标,对成都市三环路内约200km2热力景观空间格局的研究结果表明:5个行政区的热力景观格局指数存在显著差别,如锦江区的破碎度指数最大,为0.924,成华区的最小,为0.559,指数大小与城市热力景观类型的分布特点密切相关。这些结果对于分析和研究城市整体格局、城市规划和环境保护等具有应用意义。  相似文献   
200.
Based on sustainable development theory and the UN's Human Development Index, this thesis puts forward what the quality of urban life implies, makes a study of the world Expo's potential influences on the urban life of Shanghai and advances the strategy and measures to strengthen the life-quality-facing urban management  相似文献   
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