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951.
Genetic mechanisms determining habitat selection and specialization of individuals within species have been hypothesized, but not tested at the appropriate individual level in nature. In this work, we analyzed habitat selection for 139 GPS-collared caribou belonging to 3 declining ecotypes sampled throughout Northwestern Canada. We used Resource Selection Functions comparing resources at used and available locations. We found that the 3 caribou ecotypes differed in their use of habitat suggesting specialization. On expected grounds, we also found differences in habitat selection between summer and winter, but also, originally, among the individuals within an ecotype. We next obtained Single Nucleotide Polymorphisms (SNPs) for the same caribou individuals, we detected those associated to habitat selection, and then identified genes linked to these SNPs. These genes had functions related in other organisms to habitat and dietary specializations, and climatic adaptations. We therefore suggest that individual variation in habitat selection was based on genotypic variation in the SNPs of individual caribou, indicating that genetic forces underlie habitat and diet selection in the species. We also suggest that the associations between habitat and genes that we detected may lead to lack of resilience in the species, thus contributing to caribou endangerment. Our work emphasizes that similar mechanisms may exist for other specialized, endangered species.  相似文献   
952.
With the intention of securing industry-free land and seascapes, protecting wilderness entered international policy as a formal target for the first time in the zero draft of the Post-2020 Global Biodiversity Framework under the Convention on Biological Diversity. Given this increased prominence in international policy, it is timely to consider the extent to which the construct of wilderness supports global conservation objectives. We evaluated the construct by overlaying recently updated cumulative human pressure maps that offer a global-scale delineation of industry-free land as wilderness with maps of carbon stock, species richness, and ground travel time from urban centers. Wilderness areas took variable forms in relation to carbon stock, species richness, and proximity to urban centers, where 10% of wilderness areas represented high carbon and species richness, 20% low carbon and species richness, and 3% high levels of remoteness (>48 h), carbon, and species richness. Approximately 35% of all remaining wilderness in 2013 was accessible in <24 h of travel time from urban centers. Although the construct of wilderness can be used to secure benefits in specific contexts, its application in conservation must account for contextual and social implications. The diverse characterization of wilderness under a global environmental conservation lens shows that a nuanced framing and application of the construct is needed to improve understanding, communication, and retention of its variable forms as industry-free places.  相似文献   
953.
ABSTRACT: The planning and developing of water resources to meet the country's needs for water supply, flood control, hydroelectric power, irrigation, and navigation now needs to take more account of environmental needs and regulations. Water resource development is often beneficial to the environment, but may also be harmful, as in cases involving salmon and various other endangered species. As a national objective, the environment must be preserved and in some cases restored; but how can this be done consistent with other national objectives, relating to life and welfare of human beings? This problem has aroused the concern of many engineers and water scientists. As a result, a national conference on this subject was held in Chicago in June 1998, as an integral part of ASCE's Annual Conference on Water Resources Planning and Management and the Annual Conference on Environmental Engineering. At the conclusion of that conference, a post-conference meeting was held by a group of prominent water resource practitioners. It was concluded at this meeting that action should be taken by our government to establish a new form of interagency approach, involving the states, as a means of coordination in cases of national importance.  相似文献   
954.
本文根据我国珍稀濒危植物的保护现状和管理工作中存在的问题,系统地探讨了加强我国珍稀濒危植物和野生植物资源保护的政策措施。文中提出一系列具体、有效的政策构思,以及建立政府有关主管部门对珍稀濒危植物协调管理的体制等。  相似文献   
955.
The Thar Desert of North-west India has sprung into prominence recently because of nuclear testing in 1998. It occupies about 3 million km2 of diverse habitat. Each of the various habitats and landforms in the desert supports distinctive plants. 682 plant species have been identified including 107 grasses. Plants are removed for fuel, fodder, fencing and other farming, domestic and commercial purposes. There are about 200 species of plants with recognised medicinal uses in the desert. The medicinal usefulness of others is yet to be established. Commiphora wightii, Withania somnifera and Urginia indica have high glycoside content and are valued for gums and used in ayurvedic medicines for enhancing mental retention and memory enhancement. Such plants are being indiscriminately exploited for fuelwood.  相似文献   
956.
The Carpentarian rock-rat (Zyzomys palatalis) is a critically endangered endemic rodent known from only four sandstone gorges in the southeast Gulf of Carpentaria, Northern Territory, Australia. These gorges harbour thickets of monsoon rainforest and broadleaf woodland, surrounded by a Eucalypt savanna matrix. The long-term persistence of Z. palatalis is threatened by altered fire regimes, grazing by feral animals and stock, weed intrusion, and the stochastic hazards associated with small, fragmented populations. To assess the relative importance of these threats and develop practical management options, a population and habitat simulation model was developed, based on the best existing data. Population viability was predicted to be highly sensitive to the frequency of hot, late dry-season fires. Progressive habitat degradation (due predominantly to intense late dry-season fires) is likely to substantially reduce population size and lead to the probable extinction of the species within the next 100 years. The most effective management strategy to counteract this threat would be regular, controlled, fuel reduction burns in the vegetation around the gorge entrances during the early dry season. Establishing a new population (through translocation of captive-bred individuals) would not appreciably reduce extinction risk, but could provide valuable additional data on the impact of threats, if conducted as an adaptive management experiment.  相似文献   
957.
Single-species listings under provisions of the federal Endangered Species Act (ESA) have caused, or have been accused of causing, significant regional economic impact. In an attempt to avoid such adverse effects on regional economic development, the state of California passed the Natural Communities Conservation Planning Act (NCCP) in 1991. It is a voluntary, consensus-based approach to balancing protection of sensitive biota and biodiversity with regional economic development. The pilot NCCP program for the conservation of several threatened, endangered, and category 1 species, plus an additional 35 coastal sage scrub-related species in southern California, was completed and submitted to the public for review and comment in December 1995. This program proposes the voluntary establishment of a 86,600-ha multispecies reserve system. Once completed, participating landowners will receive ESA Section 10(a) incidental take permits for present and identified future projects. Utility rights-of-way are incorporated into the program as important connective linkages between reserve units and other adjacent important habitat areas. All data and information regarding the proposed results of the NCCP are subject to change pending agency response to public comments on the draft Habitat Conservation Plan and joint EIR/EIS.  相似文献   
958.
Security buffers of Department of Defense (DoD) and Department of Energy (DOE) reservations provide long-term habitat protection for many rare and endangered species. The importance of these government-owned reservations as nationally valuable resources has been relatively unrecognized. During the last 50 years, the DOE Oak Ridge Reservation (ORR) has been a relatively protected island in a region of rapidly expanding urbanization and land clearing. Consisting of the Oak Ridge National Environmental Research Park and associated lands surrounding DOE facilities at Oak Ridge Tennessee, the unique nature of the ORR in the surrounding landscape is clearly visible from the air and has been documented using remote sensing data. Although forests dominate much of other regions of eastern Tennessee, this 15,000-ha tract of mostly natural forest habitat is unique in the southern Ridge and Valley physiographic province, which is otherwise widely developed for pasture, marginal cropland, woodlot, and urban uses. Twenty state-listed and federal-candidate plant species are known to be present on the ORR. This richness of species, which are provided protection by state and federal laws, exceeds that of the Great Smoky Mountains National Park on a species area basis and is an index of the value of the ORR both regionally and nationally in conserving biodiversity. With the end of the Cold War, changing DoD and DOE missions combined with increasing development pressure contribute to uncertainty in the future management of security reservations.  相似文献   
959.
Phytoremediation offers a cost-effective,non-intrusive,and safe alternative to conventional cleanup techniques.In this study,we used ornamental hydrophytes plants as constructed wetlands to treat urban or rural domestic wastewater.Most ornamental hydrophytes adapted to the wastewater well,and were fairly efficient in scavenging BOD_5(biological oxygen demand 5 d),COD(chemical oxygen demand),TN(total nitrogen),TP(total phosphorus)and heavy metals(Cr,Pb,Cd)in the wastewater.However,the efficiency varied a lot for various species to different contaminants,Iris pseudacorus L.and Acorus gramineus Soland were good choices for treatment of composite-polluted urban wastewater.Some variation in the change of membrane peroxidation and endogenous protective system in responses to wastewater was found among six hydrophytes,which have a correlation with the efficiency of wastewater treatment.It may demonstrate that the developed antioxidative systems of I.pseudacorus and A.gramineus contributed much to their superiority. On the other hand,interaction of different components in the wastewater might have certain effects on phytoremediation.  相似文献   
960.
中美水生生物基准受试物种敏感性差异研究   总被引:7,自引:1,他引:7  
我国已经系统地采用物种敏感度分布(species sensitivity distribution,SSD)法开展水生生物基准研究工作.由于水体污染物种类繁多,因此在建立我国水生生物基准的过程中面临着本土生物毒性数据缺乏的问题.本研究通过物种敏感性比较,以美国为例对采用非本土生物毒性数据来推导我国水生生物基准的可行性进行了分析.首先,以US EPA推荐的58种污染物的水生生物基准为基础,筛选出中美两国共有的且生物毒性数据满足"3门8科"要求的10种污染物:As(Ⅲ)、Cr(Ⅵ)、Hg、Cu、Pb、Zn、硝基苯、对硫磷、毒死蜱、三丁基锡;然后,采用双样本Kolmogorov-Smirnov(K-S)检验法和重要点位(hazardous concentration for 5%of the species and 50%of the species,HC5和HC50)差异分析法对10种污染物的中美物种敏感性差异进行研究.结果表明:通过双样本K-S检验得出中美物种对Cu、毒死蜱、三丁基锡的敏感性分布存在显著性差异(P0.05);通过重要点位值进行差异比较得出中美两国Cr(Ⅵ)、毒死蜱的HC5值差异超过一个数量级,毒死蜱的HC50值差异超过一个数量级,表明有些污染物[如:Cr(Ⅵ)、毒死蜱等]的中美间物种敏感性差异较大,在这种情况下直接采用美国的生物毒性数据或基准值来保护我国的水生生物,可能会存在"欠保护"或"过保护"的风险.  相似文献   
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