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101.
根据2009年8月和2010年5月大、小长山岛周围海域浮游动物春、夏季航次调查资料,对该海域浮游动物种类组成、优势种、生物量及其分布、密度及其分布、生物多样性等进行了分析。结果表明:春、夏季共检出浮游动物34种,主要种类为近岸低盐种,其中春季23种,夏季30种;优势种9种,以桡足类占优势,主要为中华哲水蚤、小拟哲水蚤、大同拟长腹剑水蚤和双刺纺锤水蚤等,优势种季节变化较明显。浮游动物密度、生物量、多样性指数和均匀度指数等季节水平分布特征变化明显,并与温度和盐度呈显著相关。聚类分析显示大、小长山岛周围海域浮游动物群落春、夏季相似度较高。与20世纪80年代相比,本次调查浮游动物群落已发生了一定程度的变化。  相似文献   
102.
ABSTRACT

The 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   
103.
There are two approaches in the application of satellite sensors to marine pollution studies. Satellite sensors are used to observe and characterize ocean pollutants such as industrial wastes and oil. in addition, satellite observations provide information useful in illuminating processes such as eutrophi-cation or air-sea exchange of CO2, that are important in determining the distribution and fate of pollutants.

Satellite technology is an important tool in monitoring and studying ocean pollution. Visible sensors have been used to observe and characterize sewage sludge and industrial wastes dumped at sea. Oil slicks have been observed with Landsat, AVHRR and SAR imagery. Besides directly detecting pollutants, satellite sensors are useful for analyzing ocean processes that are influential in the fate of pollutants. These processes include eutrophication of coastal waters and the distribution of suspended matter. the fate of excess CO2 can be addressed using scatterometer-derived estimates of wind speeds to determine the CO2 exchange coefficient at the sea surface on a global scale.  相似文献   
104.
In the past few decades, the tourism sector has emerged as a significant economic activity in island nations, particularly in tropical regions. However, most of the tropical islands face similar constraints, viz., threat to natural resources, chances of biopiracy, impact of climate change, population pressure and unsystematic tourist management. Ecotourism, as a concept, envisages promoting tourism with due regard to natural environment and ecological sanctity of the destination. Archipelago of Andaman and Nicobar (A&N) Islands is one of picturesque geographical creation in the Bay of Bengal, India, in tropical region and is an emerging tourist destination. It was observed that around 2.2 lakhs national and international tourists visit the A&N Islands annually. With tourism sector as an integral component, the service sector with share of 56% in gross state domestic product dominates the island economy. An analysis based on primary survey from various stakeholders associated with the sector revealed that factors such as economy in travel and boarding, availability of tourist facilities and comfort, safety, etc. were major factors that determined the choice of the tourists that visited the islands. The weights given by the tourists to the natural sites in A&N Islands revealed that the landscape topped list with 91.6% score by the visitors followed by beaches (91.3%), scenery (86.5%), reserved forests (84.6%), limestone caves (66.3%) and coral sights (65.8%). Coral sites were given weight of 65.8% of tourists, cultural and historical tourism products 85.4% for the natural history. Similarly, historical sites (83.7%), museums (78.6%) and heritage sites (72.8%) were also among top cites attraction. Recent initiatives by the Andaman administration gives due to care to sustainably develop the tourism infrastructure of the islands to harness the potential of eco-friendly tourism in this picturesque tourist haven.  相似文献   
105.
Bird song is a sexually selected multidimensional signal. A fundamental question regarding the evolution of sexually selected signals is what information they convey and how their honesty is maintained. Song amplitude is a performance-related signal trait that varies considerably between individuals, but this signal dimension has been neglected in past studies. I found that median song amplitude in male nightingales (Luscinia megarhynchos) and zebra finches (Taeniopygia guttata) did not vary significantly with body size or residual body mass. In contrast, I found a significant negative correlation between body size (and also residual mass) and the maximum song amplitude during interactive singing in nightingales. However, the function of these more subtle differences in song amplitude remains to be investigated. By and large, the results of this study suggest that mean song amplitude is unlikely to indicate a bird’s body size or current condition (measured as residual mass).  相似文献   
106.
Several recent studies have tested the hypothesis that song quality in adult birds may reflect early developmental conditions, specifically nutritional stress during the nestling period. Whilst all of these earlier studies found apparent links between early nutritional stress and song quality, their results disagree as to which aspects of song learning or production were affected. In this study, we attempted to reconcile these apparently inconsistent results. Our study also provides the first assessment of song amplitude in relation to early developmental stress and as a potential cue to male quality. We used an experimental manipulation in which the seeds on which the birds were reared were mixed with husks, making them more difficult for the parents to obtain. Compared with controls, such chicks were lighter at fledging; they were thereafter placed on a normal diet and had caught up by 100 days. We show that nutritional stress during the first 30 days of life reduced the birds’ accuracy of song syntax learning, resulting in poorer copies of tutor songs. Our experimental manipulations did not lead to significant changes in song amplitude, song duration or repertoire size. Thus, individual differences observed in song performance features probably reflect differences in current condition or motivation rather than past condition.  相似文献   
107.
舟山本岛大气污染输送过程的数值模拟分析   总被引:2,自引:0,他引:2       下载免费PDF全文
利用HYSPLIT-4后向轨迹模式和NCEP(美国国家环境预报中心)的2012年GDAS(全球资料同化系统)气象数据,结合NO2、PM2.5、PM10和SO2等常规大气污染物的质量浓度数据,对舟山本岛2012年4月、7月、10月和12月的大气污染输送过程进行了模拟,并通过聚类分析和潜在源区分析〔包括PSCF(潜在源贡献)和CWT(浓度权重轨迹)计算〕,确定大气污染传输路径及影响源区. 结果表明:舟山本岛气流后向轨迹呈明显的季节变化特征,4月主要受来自黄海海面气流轨迹的影响,其占总轨迹数的36.7%,ρ(PM10)为(53.24±24.33)μg/m3;7月以途经琉球群岛和东海气流轨迹为主,占总轨迹数的48.4%,对ρ(NO2)、ρ(PM2.5)、ρ(PM10)和ρ(SO2)贡献分别为(24.63±6.33)、(28.60±4.83)、(52.89±18.76)和(8.67±3.11)μg/m3;10月气流轨迹主要来自于东海海面,占总轨迹数的49.2%;12月气流则主要来自辽宁南部和黄海,占总轨迹数的66.1%,对ρ(NO2)、ρ(PM2.5)、ρ(PM10)和ρ(SO2)贡献分别为(28.48±15.14)、(58.71±14.10)、(69.83±38.94)和(20.83±13.28)μg/m3. 舟山本岛PM2.5的潜在源主要为毗邻城市间局地污染,集中于浙江沿海城市及杭州湾、上海等地.   相似文献   
108.
Long-term population declines have elevated recovery of grassland avifauna to among the highest conservation priorities in North America. Because most of the Great Plains is privately owned, recovery of grassland bird populations depends on voluntary conservation with strong partnerships between private landowners and resource professionals. Despite large areas enrolled in voluntary practices through U.S. Department of Agriculture's Lesser Prairie-chicken (Tympanuchus pallidicinctus) Initiative (LPCI), the effectiveness of Farm Bill investments for meeting wildlife conservation goals remains an open question. Our objectives were to evaluate extents to which Conservation Reserve Program (CRP) and LPCI-grazing practices influence population densities of grassland birds; estimate relative contributions of practices to regional bird populations; and evaluate percentages of populations conserved relative to vulnerability of species. We designed a large-scale impact-reference study and used the Integrated Monitoring in Bird Conservation Regions program to evaluate bird population targets of the Playa Lakes Joint Venture. We used point transect distance sampling to estimate density and population size for 35 species of grassland birds on private lands enrolled in native or introduced CRP plantings and LPCI-prescribed grazing. Treatment effects indicated CRP plantings increased densities of three grassland obligates vulnerable to habitat loss, and LPCI grazing increased densities of four species requiring heterogeneity in dense, tall-grass structure (α = 0.1). Population estimates in 2016 indicated the practices conserved breeding habitat for 4.5 million birds (90% CI: 4.0–5.1), and increased population sizes of 16 species , totaling 1.8 million birds (CI: 1.4–2.4). Conservation practices on private land benefited the most vulnerable grassland obligate species (AICc weight = 0.53). By addressing habitat loss and degradation in agricultural landscapes, conservation on private land provides a solution to declining avifauna of North America and scales up to meet population recovery goals for the most imperiled grassland birds.  相似文献   
109.
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   
110.
In spite of the wide diversity in the economic performance of small island developing states (SIDS), the apparent prosperity of several SIDS has entailed a global misrepresentation of the economic situation of these countries. While their vulnerability to natural disasters is not denied, the general risk of economic marginalization that many SIDS face in the context of globalization may not have received sufficient attention. The paper attempts to highlight what matters most in the consideration of the economic vulnerability of SIDS and in the debate to prevent their marginalization. It examines the main types of external shocks to which SIDS are vulnerable, and discusses the economic handicaps that are fundamental causes of this vulnerability. Economic specialization (with the predominance of international trade in services) is then a central notion in the analysis of island vulnerability: a better specialization, which may involve diversification and always implies greater international competitiveness, can reduce the exposure or vulnerability of SIDS to external shocks, and induce greater economic stability in these countries. Hence the importance of developing policies to circumvent the specific handicaps of islands and facilitate the realization of new trading opportunities through an emulative use of globalization forces.  相似文献   
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