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Some conservation prioritization methods are based on the assumption that conservation needs overwhelm current resources and not all species can be conserved; therefore, a conservation triage scheme (i.e., when the system is overwhelmed, species should be divided into three groups based on likelihood of survival, and efforts should be focused on those species in the group with the best survival prospects and reduced or denied to those in the group with no survival prospects and to those in the group not needing special efforts for their conservation) is necessary to guide resource allocation. We argue that this decision-making strategy is not appropriate because resources are not as limited as often assumed, and it is not evident that there are species that cannot be conserved. Small population size alone, for example, does not doom a species to extinction; plants, reptiles, birds, and mammals offer examples. Although resources dedicated to conserving all threatened species are insufficient at present, the world's economic resources are vast, and greater resources could be dedicated toward species conservation. The political framework for species conservation has improved, with initiatives such as the UN Sustainable Development Goals and other international agreements, funding mechanisms such as The Global Environment Facility, and the rise of many nongovernmental organizations with nimble, rapid-response small grants programs. For a prioritization system to allow no extinctions, zero extinctions must be an explicit goal of the system. Extinction is not inevitable, and should not be acceptable. A goal of no human-induced extinctions is imperative given the irreversibility of species loss.  相似文献   
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Guidelines for Subspecific Substitutions in Wildlife Restoration Projects   总被引:2,自引:0,他引:2  
Reintroduction of animals is becoming increasingly popular as a means of restoring populations of threatened species. Sometimes depletion of wild populations leaves only captive populations from which reintroduction projects can obtain founders for releases. The World Conservation Union guidelines on reintroductions recommend that the individuals to be reintroduced should be of the same subspecies as those that were extirpated. In some cases, however, a subspecies may have become extinct in the wild and in captivity. A substitute form may then be chosen for possible release. Such substitutions are actually a form of benign introduction. Considerations include assessment of the value of a substitution project and the selection of a suitable substitute. Species substitutions increase biodiversity, conserve related forms, improve public awareness of conservation issues, educate the public, and may be implemented for aesthetic or economic reasons. Selection of a suitable substitute should focus on extant subspecies and consider genetic relatedness, phenotype, ecological compatibility, and conservation value of potential candidates. An example of a substitution project is the reintroduction of the North African Red-necked Ostrich (  Struthio camelus camelus ) into areas once occupied by the now extinct Arabian Ostrich (  Struthio camelus syriacus ). S. c. camelus was chosen as a substitute because of its geographic proximity, phenotypic similarity, and conservation value. The World Conservation Union's reintroduction guidelines should be consulted before a project is begun.  相似文献   
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Data on flora and vegetation of 14 off-shore islands representing different habitat types were studied for investigating floristic composition, vegetation types and correlation with their habitats and ecosystem. The results demonstrate considerable plant distribution and diversity among the islands within the limited spectrum of species; encompassing a total of 47 species, belonging to 43 genera under 24 families. The most representative families were Amaranthaceae (9 species), Fabaceae (4 species), Poaceae (4 species) and Asteraceae and Aizoaceae (3 species each). Fourteen families are represented by only one species. The mangrove species, Avicennia marina, occurs throughout the coast of Abu Dhabi in discontinuous patches and in different water salinities. The studies also seek to underline that dominant species that constitutes the flora of Abu Dhabi are salt tolerant in nature. Compared to other Arabian Peninsula ecosystems, UAE perhaps has a higher coastal: mainland area ratio, which has contributed to a natural dominance of salt tolerant species among the community. The studies show 40% similarity among islands with respect to the species diversity. The floristic composition of the off-shore islands also indicates a need to consider these sites as protected sites.  相似文献   
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