Favaro Brett, Claar Danielle C, Fox Caroline H, Freshwater Cameron, Holden Jessica J, Roberts Allan
Department of Biology, University of Victoria, Victoria, Canada; Centre for Sustainable Aquatic Resources, Fisheries and Marine Institute of Memorial University of Newfoundland, St John's, Canada; Department of Ocean Sciences, Memorial University of Newfoundland, St. John's, Canada.
Department of Biology, University of Victoria, Victoria, Canada.
PLoS One. 2014 Nov 17;9(11):e113118. doi: 10.1371/journal.pone.0113118. eCollection 2014.
Protecting and promoting recovery of species at risk of extinction is a critical component of biodiversity conservation. In Canada, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) determines whether species are at risk of extinction or extirpation, and has conducted these assessments since 1977. We examined trends in COSEWIC assessments to identify whether at-risk species that have been assessed more than once tended to improve, remain constant, or deteriorate in status, as a way of assessing the effectiveness of biodiversity conservation in Canada. Of 369 species that met our criteria for examination, 115 deteriorated, 202 remained unchanged, and 52 improved in status. Only 20 species (5.4%) improved to the point where they were 'not at risk', and five of those were due to increased sampling efforts rather than an increase in population size. Species outcomes were also dependent on the severity of their initial assessment; for example, 47% of species that were initially listed as special concern deteriorated between assessments. After receiving an at-risk assessment by COSEWIC, a species is considered for listing under the federal Species at Risk Act (SARA), which is the primary national tool that mandates protection for at-risk species. We examined whether SARA-listing was associated with improved COSEWIC assessment outcomes relative to unlisted species. Of 305 species that had multiple assessments and were SARA-listed, 221 were listed at a level that required identification and protection of critical habitat; however, critical habitat was fully identified for only 56 of these species. We suggest that the Canadian government should formally identify and protect critical habitat, as is required by existing legislation. In addition, our finding that at-risk species in Canada rarely recover leads us to recommend that every effort be made to actively prevent species from becoming at-risk in the first place.
保护和促进濒危物种的恢复是生物多样性保护的关键组成部分。在加拿大，加拿大濒危野生动物状况委员会（COSEWIC）确定物种是否面临灭绝或局部灭绝的风险，并且自1977年以来一直在进行这些评估。我们研究了COSEWIC评估的趋势，以确定多次接受评估的濒危物种在状态上是趋于改善、保持不变还是恶化，以此来评估加拿大生物多样性保护的成效。在符合我们审查标准的369个物种中，115个物种的状况恶化，202个保持不变，52个有所改善。只有20个物种（5.4%）改善到了“无风险”状态，其中5个是由于抽样力度加大而非种群数量增加。物种的评估结果还取决于其初始评估的严重程度；例如，最初被列为特别关注的物种中有47%在两次评估之间状况恶化。在接受COSEWIC的濒危评估后，一个物种会被考虑列入联邦《濒危物种法》（SARA），这是国家保护濒危物种的主要工具。我们研究了相对于未列入该法案的物种，列入SARA是否与COSEWIC评估结果的改善相关。在有多次评估且被列入SARA的305个物种中，221个被列入的级别要求识别和保护关键栖息地；然而，其中只有56个物种的关键栖息地得到了全面识别。我们建议加拿大政府应按照现有立法的要求，正式识别和保护关键栖息地。此外，我们发现加拿大的濒危物种很少恢复，这使我们建议应尽一切努力首先积极防止物种成为濒危物种。
