关于物种濒危等级标准之探讨——对IUCN物种濒危等级的思考

Exploring the endangered species criteria: rethinking the IUCN Red List Criteria

为了保存地球上的生物多样性 ,我们需要根据物种的种群数量与分布、种群数量波动与分布区下降速率来评定濒危物种的濒危等级 ,并针对物种的濒危等级提出具体的保护措施。 1994年 11月 ,IUCN第 4 0次理事会会议正式通过了经过修订的Mace Lande物种濒危等级标准作为IUCN物种濒危等级标准。IUCN濒危物种红色名录虽然不是国际法和国家法律 ,但是对于政府间组织、非政府组织的保护决策以及各国的自然法律法规的制定有着深远的影响 ,在保护生物学理论研究中也发挥了一定作用。我们在研究制定中国水生野生生物濒危等级标准时发现 ,如果直接应用IUCN物种濒危等级标准评定水生野生生物濒危等级将存在一些问题。如 :(1)如何区别对待那些本来就数量稀少、分布区狭窄的物种和那些由于人类活动而导致其种群数量与生境面积急剧下降的物种 ?(2 )不同的动物类群能否应用同一濒危标准尺度 ?(3)如何区别对待物种边缘分布区和核心分布区的种群数量与密度的差异 ?(4 )如何处理种群的局部灭绝、局部濒危 ?(5 )一些濒危物种在野生环境中濒危 ,但是这些物种可以人工繁殖 ,如何处理可以人工繁殖的濒危物种 ?(6 )如果没有种群与栖息地的精确历史资料和统计数据 ,怎样应用物种的濒危标准评估其濒危等级 ?在实践中 ,我们针对这些问?

For preserving global biodiversity, we should evaluate the level of endangerment of a species based on information such as number and distribution of individuals, fluctuations and decline in abundance and distribution, and risk of extinction. We should then design conservation measures accordingly. The Species Survival Commission of IUCN has devoted itself to the study of IUCN Red List Criteria. The IUCN 40th Council Meeting adopted the so called modified Mace Lande Endangered Species Criteria as the standard criteria for the IUCN Red List in November 1994. The Red List is intended to focus national and local conservation actions on the species that most need support. Although the IUCN Red List is not an international law, it has deep impact on conservation decision making in governmental and nongovernmental organizations, as well as on conservation law and policy making in many countries. The IUCN Red List Criteria also have had a profound influence on the theory of conservation biology. However, when we tried to apply the IUCN Red List Criteria to assess the status of endangered aquatic wildlife in China, we found several problems: (1) How do we distinguish those species that are naturally rare and those species whose population and habitat are declining due to human activity? (2) Can we apply the same criteria to different taxonomic groups, particularly those with different life histories? (3) How do we evaluate changes in population density that occur in the core habitat versus those that occur in peripheral habitats of the same species? (4) How should we treat the extirpation of local populations in a metapopulation? (5) How to deal with those species that can be successfully bred in captivity? (6) If we do not have accurate historical and current population and habitat status data, how do we evaluate the level of endangerment of those species? We suggest solutions to those problems in this paper. Firstly, we set up simplified endangered species criteria categories: 'Least concern', 'Concern', 'Threatened', 'Endangered' and 'Extinct', of which, 'Concern', 'Threatened', and 'Endangered' are further divided into two levels: 'ordinary' and 'highly'. We further suggest distinguishing ecologically endangered species versus evolutionarily endangered species, and evaluating species with different life histories, for examples, the K strategists and r strategists, with different criteria. Third, we suggest the introduction of 'Economically Endangered' as a criterion of 'Threatened' for r strategy species. Fourth, more conservation attention should be allocated to endemic species. Finally, we introduce the metapopulation concept into evaluation of endangered aquatic wildlife.