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21.
Abstract: The majority of bird extinctions since 1800 have occurred on islands, and non‐native predators have been the greatest threat to the persistence of island birds. Island endemic species often lack life‐history traits and behaviors that reduce the probability of predation and they can become evolutionarily trapped if they are unable to adapt, but few studies have examined the ability of island species to respond to novel predators. The greatest threat to the persistence of the Oahu Elepaio (Chasiempis ibidis), an endangered Hawaiian forest bird, is nest predation by non‐native black rats (Rattus rattus). I examined whether Oahu Elepaio nest placement has changed at the individual and population levels in response to rat predation by measuring nest height and determining whether each nest produced offspring from 1996 to 2011. Average height of Oahu Elepaio nests increased 50% over this 16‐year period, from 7.9 m (SE 1.7) to 12.0 m (SE 1.1). There was no net change in height of sequential nests made by individual birds, which means individual elepaios have not learned to place nests higher. Nests ≤3 m off the ground produced offspring less often, and the proportion of such nests declined over time, which suggests that nest‐building behavior has evolved through natural selection by predation. Nest success increased over time, which may increase the probability of long‐term persistence of the species. Rat control may facilitate the evolution of nesting height by slowing the rate of population decline and providing time for this adaptive response to spread through the population.  相似文献   
22.
Matching the trend seen among the major large rivers of the globe, the Amazon River and its tributaries are facing aquatic ecosystem disruption that is affecting freshwater habitats and their associated biodiversity, including trends for decline in fishery resources. The Amazon’s aquatic ecosystems, linked natural resources, and human communities that depend on them are increasingly at risk from a number of identified threats, including expansion of agriculture; cattle pastures; infrastructure such as hydroelectric dams, logging, mining; and overfishing. The forest, which regulates the hydrological pulse, guaranteeing the distribution of rainfall and stabilizing seasonal flooding, has been affected by deforestation. Flooding dynamics of the Amazon Rivers are a major factor in regulating the intensity and timing of aquatic organisms. This study’s objective was to identify threats to the integrity of freshwater ecosystems, and to seek instruments for conservation and sustainable use, taking principally fish diversity and fisheries as factors for analysis.  相似文献   
23.
Megafauna species are intrinsically vulnerable to human impact. Freshwater megafauna (i.e., freshwater animals ≥30 kg, including fishes, mammals, reptiles, and amphibians) are subject to intensive and increasing threats. Thirty-four species are listed as critically endangered on the International Union for Conservation of Nature (IUCN). Red List of Threatened Species, the assessments for which are an important basis for conservation actions but remain incomplete for 49 (24%) freshwater megafauna species. Consequently, the window of opportunity for protecting these species could be missed. Identifying the factors that predispose freshwater megafauna to extinction can help predict their extinction risk and facilitate more effective and proactive conservation actions. Thus, we collated 8 life-history traits for 206 freshwater megafauna species. We used generalized linear mixed models to examine the relationships between extinction risk based on the IUCN Red List categories and the combined effect of multiple traits, as well as the effect of human impact on these relationships for 157 classified species. The most parsimonious model included human impact and traits related to species’ recovery potential including life span, age at maturity, and fecundity. Applying the most parsimonious model to 49 unclassified species predicted that 17 of them are threatened. Accounting for model predictions together with IUCN Red List assessments, 50% of all freshwater megafauna species are considered threatened. The Amazon and Yangtze basins emerged as global diversity hotspots of threatened freshwater megafauna, in addition to existing hotspots, including the Ganges-Brahmaputra and Mekong basins and the Caspian Sea region. Assessment and monitoring of those species predicted to be threatened are needed, especially in the Amazon and Yangtze basins. Investigation of life-history traits and trends in population and distribution, regulation of overexploitation, maintaining river connectivity, implementing protected areas focusing on freshwater ecosystems, and integrated basin management are required to protect threatened freshwater megafauna in diversity hotspots.  相似文献   
24.
完善的危化品港区应急管理体系能够有效的预防和减少事故,将风险和损失降到 最低。针对中国危化品港区应急管理现状,提出了基于生物免疫识别机理的SWOT-ANP综 合分析模型。从优势-劣势-机遇-威胁(SWOT) 4个方面对现状进行分析,确定和建立 应急管理指标体系。分别采用AHP和ANP方法对各因素之间的相互依赖和反馈关系加以比 较并分析计算。对比结果表明:虽然国家对危化品港区应急管理方面关注度有所增强, 但是仍然存在应急文化缺失,审查监管不足和预警机制不完善等问题,目前发展的最佳 战略是SO战略组合。  相似文献   
25.
The Endangered Species Act (ESA) of the United States was enacted in 1973 to prevent the extinction of species. Recovery plans, required by 1988 amendments to the ESA, play an important role in organizing these efforts to protect and recover species. To improve the use of science in the recovery planning process, the Society for Conservation Biology (SCB) commissioned an independent review of endangered species recovery planning in 1999. From these findings, the SCB made key recommendations for how management agencies could improve the recovery planning process, after which the U.S. Fish and Wildlife Service and the National Marine Fisheries Service redrafted their recovery planning guidelines. One important recommendation called for recovery plans to make threats a primary focus, including organizing and prioritizing recovery tasks for threat abatement. We sought to determine the extent to which results from the SCB study were incorporated into these new guidelines and whether the SCB recommendations regarding threats manifested in recovery plans written under the new guidelines. Recovery planning guidelines generally incorporated the SCB recommendations, including those for managing threats. However, although recent recovery plans have improved in their treatment of threats, many fail to adequately incorporate threat monitoring. This failure suggests that developing clear guidelines for monitoring should be an important priority in improving ESA recovery planning.  相似文献   
26.
Abstract: The importance of biodiversity as natural capital for economic development and sustaining human welfare is well documented. Nevertheless, resource degradation rates and persistent deterioration of human welfare in developing countries is increasingly worrisome. Developing effective monitoring and evaluation schemes and measuring biodiversity loss continue to pose unique challenges, particularly when there is a paucity of historical data. Threat reduction assessment (TRA) has been proposed as a method to measure conservation success and as a proxy measurement of conservation impact, monitoring threats to resources rather than changes to biological parameters themselves. This tool is considered a quick, practical alternative to more cost‐ and time‐intensive approaches, but has inherent weaknesses. I conducted TRAs to evaluate the effectiveness of Kruger National Park (KNP) and Limpopo Province, South Africa, in mitigating threats to biodiversity from 1994 to 2004 in 4 geographical areas. I calculated TRA index values in these TRAs by using the original scoring developed by Margoluis and Salafsky (2001) and a modified scoring system that assigned negative mitigation values to incorporate new or worsening threats. Threats were standardized to allow comparisons across the sites. Modified TRA index values were significantly lower than values derived from the original scoring exercise. Five of the 11 standardized threats were present in all 4 assessment areas, 2 were restricted to KNP, 2 to Limpopo Province, and 2 only to Malamulele municipality. These results indicate, first, the need to integrate negative mitigation values into TRA scoring. By including negative values, investigators will be afforded a more accurate picture of biodiversity threats and of temporal and spatial trends across sites. Where the original TRA scoring was used to measure conservation success, reevaluation of these cases with the modified scoring is recommended. Second, practitioners must carefully consider the need and consequences of generalizing threats into generic categories for comparative assessments. Finally, continued refinement of the methodology and its extension to facilitate the transfer of successful conservation strategies is needed.  相似文献   
27.
Incentivized debt conversion is a financing mechanism that can assist countries with a heavy debt burden to bolster their long-term domestic investment in nature conservation. The Nature Conservancy, an international conservation-based nongovernmental organization, is adapting debt conversions to support marine conservation efforts by small island developing states and coastal countries. Prioritizing debt conversion opportunities according to their potential return on investment can increase the impact and effectiveness of this finance mechanism. We developed guidance on how to do so with a decision-support approach that relies on a novel threat-based adaptation of cost-effectiveness analysis. We constructed scenarios by varying parameters of the approach, including enabling conditions, expected benefits, and threat classifications. Incorporating both abatable and unabatable threats affected priorities across planning scenarios. Similarly, differences in scenario construction resulted in unique solution sets for top priorities. We show how environmental organizations, private entities, and investment banks can adopt structured prioritization frameworks for making decisions about conservation finance investments, such as debt conversions. Our guidance can accommodate a suite of social, ecological, and economic considerations, making the approach broadly applicable to other conservation finance mechanisms or investment strategies that seek to establish a transparent process for return-on-investment decision-making.  相似文献   
28.
29.
Abstract:  The general context of conservation in the tropics—in the Amazon basin and elsewhere—is stagnant or declining funding and rapidly growing threat levels. For conservation programs this makes strategic deployment of limited conservation resources all the more important. International conservation organizations active in the tropics increasingly define themselves as science driven and expend considerable resources on science-based activities such as ecoregional analysis, field research, and monitoring of ecological variables. I argue that an overemphasis on science has generated a series of unintended but serious problems for conservation in the tropics. Spending on monitoring and ecoregional analysis has effectively starved protection and threat analysis of resources. A decoupling of biology from serious cost-benefit analysis has led to the privileging of small-scale and local analyses, rather than the systemic analyses essential for the strategic allocation of scarce conservation resources. Successful conservation in the tropics depends on the crossing of biogeography with sophisticated threat analysis to identify priority geographies for protection. This should be combined with much more systematic engagement with the principal drivers of tropical deforestation, especially agribusiness. Caution and a sense of proportion are required when balancing the financial demands of science and those of protection. I suggest that conservation organizations should cooperate far more in assembling and analyzing information on conservation spending and on threat levels and biogeography at the continental, national, and regional levels. Site selection should follow rather than precede this kind of strategic analysis, and sites should be considered elements of a network rather than stand-alone projects. More attention should be paid to market-driven conservation through techniques such as certification and responsible supply-chain management.  相似文献   
30.
Assessing temporal changes in species extinction risk is necessary for measuring conservation success or failure and for directing conservation resources toward species or regions that would benefit most. Yet, there is no long‐term picture of genuine change that allows one to associate species extinction risk trends with drivers of change or conservation actions. Through a review of 40 years of IUCN‐related literature sources on species conservation status (e.g., action plans, red‐data books), we assigned retrospective red‐list categories to the world's carnivores and ungulates (2 groups with relatively long generation times) to examine how their extinction risk has changed since the 1970s. We then aggregated species’ categories to calculate a global trend in their extinction risk over time. A decline in the conservation status of carnivores and ungulates was underway 40 years ago and has since accelerated. One quarter of all species (n = 498) moved one or more categories closer to extinction globally, while almost half of the species moved closer to extinction in Southeast Asia. The conservation status of some species improved (toward less threatened categories), but for each species that improved in status 8 deteriorated. The status of large‐bodied species, particularly those above 100 kg (including many iconic taxa), deteriorated significantly more than small‐bodied species (below 10 kg). The trends we found are likely related to geopolitical events (such as the collapse of Soviet Union), international regulations (such as CITES), shifting cultural values, and natural resource exploitation (e.g., in Southeast Asia). Retrospective assessments of global species extinction risk reduce the risk of a shifting baseline syndrome, which can affect decisions on the desirable conservation status of species. Such assessments can help conservationists identify which conservation policies and strategies are or are not helping safeguard biodiversity and thus can improve future strategies. Una Evaluación Retrospectiva de la Declinación Global de Carnívoros y Ungulados  相似文献   
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