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941.
Reforestation of bottomland hardwood (BLH) forests has occurred within the Lower Mississippi Alluvial Valley (LMAV), USA, to support a wide range of ecosystem services, but especially wildlife habitat enhancement. As ecosystem restoration efforts proceed in BLH ecosystems, managers and policymakers are seeking criteria to evaluate wildlife habitat enhancement goals. Specialist wildlife that evolved within forest ecosystems can be sensitive to the composition, structure, and function of an ecosystem in relation to the system's natural or historical range of variation and thereby serve as indicators of habitat quality. The swamp rabbit (Sylvilagus aquaticus) is a specialist species of BLH forests throughout the LMAV and therefore may be an appropriate indicator species for this ecosystem. To address this, we reviewed peer-reviewed literature to evaluate the utility of swamp rabbits as an indicator species according to three commonly-used criteria: habitat factors defining swamp rabbit relationships to BLH forests, the importance of swamp rabbit habitat to other wildlife, and the efficiency of swamp rabbit monitoring. We conclude that the swamp rabbit is a suitable indicator of wildlife habitat quality in BLH ecosystems in the LMAV because they evolved and remain endemic to the ecosystem, use habitat that integrates desirable characteristics that positively influence wildlife biodiversity, and are easy to monitor routinely.  相似文献   
942.
After the last glacial cycle, temperate European trees migrated northward, experiencing genetic bottlenecks and founder effects, which left high haplotype endemism in southern populations and clines in genetic diversity northward. These patterns are thought to be ubiquitous across temperate forests, and are therefore used to anticipate the potential genetic consequences of future warming. We compared existing and new phylogeographic data sets (chloroplast DNA) from 14 woody taxa in Eastern North America (ENA) to data sets from 21 ecologically similar European species to test for common impacts of Quaternary climate swings on genetic diversity across diverse taxa and between continents. Unlike their European counterparts, ENA taxa do not share common southern centres of haplotype endemism and they generally maintain high genetic diversity even at their northern range limits. Differences between the genetic impacts of Quaternary climate cycles across continents suggest refined lessons for managing genetic diversity in today's warming world.  相似文献   
943.
以云南南滚河国家级自然保护区内的亚洲象种群为研究对象,利用村寨调查、样线调查和3S (GIS、GPS、RS)技术对该地区野生亚洲象的栖息地状况和亚洲象在旱季对栖息地选择利用进行了初步研究。研究结果表明该地区的亚洲象偏好海拔1 000 m 以下的低海拔,坡度小于20°,坡位为平坦的沟谷和山坡的下部,坡向为东南、南、北方向的区域。偏好的植被类型是竹阔混交林和灌丛。本研究还分析了该地区自1988 ~ 2007 年20年间亚洲象栖息地的变化情况,针对目前南滚河种群及其栖息地现状提出了保护策略。  相似文献   
944.
四川扭角羚春冬季对栖息地的利用初步研究   总被引:9,自引:1,他引:8  
1998年3月至1999年2月,在四川省青川县唐家河自然保护区,对四川扭角羚(Budorcas taxicolor tibetana)春冬季对栖息地的利用进行了初步研究。结果表明,影响四川扭角羚春季栖息地利用的主要生态因子为人为干扰,植被型、乔木大小、乔木距离,乔木密度、食物丰富度,海拔,坡位、郁闭度,影响冬季栖息地利用的主要生态因子为人为干扰。植被型,乔木距离,灌木大小,灌木密度,动物干扰度,乔木大小、灌木距离,坡位,郁闭度,水源,四川扭角羚春冬季栖息地利用的分离主要表现为食物丰富度,乔木大小,乔木密度,乔木距离,植被型,水源,坡位等生存因子的分离。  相似文献   
945.
There is a growing debate about the ability of Population Viability Analysis (PVA) to predict the risk of extinction. Previously, the debate has focused largely on models where spatial variation and species movement are ignored. We present a synthesis of the key results for an array of different species for which detailed tests of the accuracy of PVA models were completed. These models included spatial variation in habitat quality and the movement of individuals across a landscape. The models were good approximations for some species, but poor for others. Predictive ability was limited by complex processes typically overlooked in spatial population models, these being interactions between landscape structure and life history attributes. Accuracy of models could not be determined a priori, although model tests indicated how they might be improved. Importantly, model predictions were poor for some species that are among the best‐studied vertebrates in Australia. This indicated that although the availability of good life history data is a key part of PVA other factors also influence model accuracy. We were also able to draw broad conclusions about the sorts of populations and life history characteristics where model predictions are likely to be less accurate. Predictions of extinction risk are often essential for real‐world population management. Therefore, we believe that although PVA has been shown to be less than perfect, it remains a useful tool particularly in the absence of alternative approaches. Hence, tests of PVA models should be motivated by the cycle of testing and improvement.  相似文献   
946.
白冠长尾雉育雏期的栖息地选择   总被引:28,自引:6,他引:22  
20 0 1年 4~ 8月 ,在河南省董寨国家级自然保护区对白冠长尾雉 (Syrmaticusreevesii)育雏期的栖息地进行了调查。野外共遇见 2 4个不同的家族群 ,平均大小为 (2 96± 0 35 )只。白冠长尾雉的家族群主要在针阔混交林中活动 ,这些地方的坡向以东南方向居多、坡度较缓而坡位靠下 ,与林缘的距离大于 6 0m而与水源的距离通常小于 30m。逐步判别分析的结果表明 ,与林缘的距离、乔木胸径、灌木盖度、草本植物的种类和高度等是影响白冠长尾雉家族群栖息地选择的关键因子 ;植被结构 ,尤其是草本植物的特征 ,是影响家族群栖息地选择的主要方面。建议在对白冠长尾雉采取保护措施时 ,从提供丰富的食物资源和良好的隐蔽条件入手。注意保护现存栖息地 ,在育雏期保护好草本植物。  相似文献   
947.
Climate change-integrated conservation strategies   总被引:8,自引:1,他引:7  
Aim Conservation strategies currently include little consideration of climate change. Insights about the biotic impacts of climate change from biogeography and palaeoecology, therefore, have the potential to provide significant improvements in the effectiveness of conservation planning. We suggest a collaboration involving biogeography, ecology and applied conservation. The resulting Climate Change‐integrated Conservation Strategies (CCS) apply available tools to respond to the conservation challenges posed by climate change. Location The focus of this analysis is global, with special reference to high biodiversity areas vulnerable to climate change, particularly tropical montane settings. Methods Current tools from climatology, biogeography and ecology applicable to conservation planning in response to climate change are reviewed. Conservation challenges posed by climate change are summarized. CCS elements are elaborated that use available tools to respond to these challenges. Results Five elements of CCS are described: regional modelling; expanding protected areas; management of the matrix; regional coordination; and transfer of resources. Regional modelling uses regional climate models, biotic response models and sensitivity analysis to identify climate change impacts on biodiversity at a regional scale appropriate for conservation planning. Expansion of protected areas management and systems within the planning region are based on modelling results. Management of the matrix between protected areas provides continuity for processes and species range shifts outside of parks. Regional coordination of park and off‐park efforts allows harmonization of conservation goals across provincial and national boundaries. Finally, implementation of these CCS elements in the most biodiverse regions of the world will require technical and financial transfer of resources on a global scale. Main conclusions Collaboration across disciplines is necessary to plan conservation responses to climate change adequately. Biogeography and ecology provide insights into the effects of climate change on biodiversity that have not yet been fully integrated into conservation biology and applied conservation management. CCS provide a framework in which biogeographers, ecologists and conservation managers can collaborate to address this need. These planning exercises take place on a regional level, driven by regional climate models as well as general circulation models (GCMs), to ensure that regional climate drivers such as land use change and mesoscale topography are adequately represented. Sensitivity analysis can help address the substantial uncertainty inherent in projecting future climates and biodiversity response.  相似文献   
948.
The European eel panmicitic population has been declining at least since the 1980s throughout its distribution area. The stocks are now ten times lower than they were initially. The causes of this decline are reviewed in this paper: marine causes such as Gulf Stream shifts are thought to reduce survival of leptocephali larvae during their transoceanic migration, but inland causes are also suspected, i.e. overfishing of all continental stages, obstructions to upstream and downstream migrations, habitat loss, water quality, parasite and xenobiotic contamination, which together contribute to reducing quality and quantity of spawner escapement from European inland waters to sea. Restoration programs have been conducted in several inland hydrosystems in Europe. If local fisheries have been sustained mainly by stocking elvers and glass eels, no significant restoration of the population has been observed suggesting that restoration plans are inefficient, despite significant efforts and relevant technologies (fish passage). The causes for the failure of restoration projects are listed and discussed, and it is shown that the minimum scale to work at is the catchment area. But international cooperation is required to coordinate programs, to determine common objectives and policies. Concepts for sustainable restoration and management are provided and discussed together with the general interest of eel population as a biointegrator of the quality and integrity of inland hydrosystems.  相似文献   
949.
950.
高黎贡山冬季白尾梢虹雉运动方式和生境偏好的初步观察   总被引:6,自引:0,他引:6  
2002及2003年1月,两次对高黎贡山大脑子白尾梢虹雉(Lophophorus sclateri)的运动方式和活动痕迹做了直接观察或样带/样方取样。该鸟滑翔是下行的主要运动方式,上行全为行走;所发现的3个夜宿地均位于坡度大、郁闭度高的近沟谷地带;冬季向低海拔迁移,与降雪有关,使得近沟谷带成为密集利用带。这样的运动和生境利用方式,显然是能耗最小化和觅食效率最大化的行为适应。  相似文献   
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