Thomas Gavin H
NERC Centre for Population Biology & Division of Biology, Imperial College London, Silwood Park, Ascot, Berkshire SL5 7PY, UK.
Proc Biol Sci. 2008 Sep 22;275(1647):2077-83. doi: 10.1098/rspb.2008.0549.
Recent studies suggest that species' life histories and ecology can be used to forecast future extinction risk. Threatened species often share similar traits such that if a trait predisposing a species to decline or extinction is evolutionarily conserved, then close relatives of threatened species are themselves likely to be at risk. The phylogenetic distribution of current threat has been argued to provide insight into the species that could be threatened in the future when trait data are not available. Conservation criteria are typically based on multiple indices that capture different symptoms of threat including population trends and range contraction. However, there is no reason to assume consistent phylogenetic distributions of different symptoms. I construct a molecular phylogeny of 249 species of British birds (more than 93% of the breeding and wintering species) and use this to show that the species that are threatened due to population declines are phylogenetically more closely related than expected by chance alone. However, species that are listed for other reasons, including range contraction, are distributed randomly with respect to phylogeny. I suggest that while phylogeny can be informative with respect to identifying clades that are susceptible to some measures of extinction risk, such patterns are likely to be idiosyncratic with respect to symptom and taxa.
近期研究表明,物种的生活史和生态特征可用于预测未来的灭绝风险。受威胁物种往往具有相似的特征,因此,如果使物种易于衰退或灭绝的特征在进化上是保守的,那么受威胁物种的近亲自身也可能处于危险之中。有人认为,当前威胁的系统发育分布有助于在缺乏特征数据时洞察未来可能受到威胁的物种。保护标准通常基于多个指标,这些指标捕捉不同的威胁症状,包括种群趋势和分布范围缩小。然而,没有理由假定不同症状的系统发育分布是一致的。我构建了249种英国鸟类(超过93%的繁殖和越冬物种)的分子系统发育树,并以此表明,因种群数量下降而受到威胁的物种在系统发育上比仅由随机因素预期的更为密切相关。然而,因其他原因(包括分布范围缩小)而被列入名单的物种在系统发育上是随机分布的。我认为,虽然系统发育在识别易受某些灭绝风险衡量标准影响的进化枝方面可能具有参考价值,但这种模式在症状和分类群方面可能是独特的。