Centre d'Ecologie et des Sciences de la Conservation (CESCO UMR7204), Sorbonne Universités, MNHN, CNRS, UPMC, CP51, 55-61 rue Buffon, 75005 Paris, France.
Department of Biology, McGill University, 1205 ave Docteur Penfield, Montreal, Quebec H3A 1B1, Canada.
Biol Rev Camb Philos Soc. 2017 Feb;92(1):271-291. doi: 10.1111/brv.12228. Epub 2015 Oct 14.
The Earth's evolutionary history is threatened by species loss in the current sixth mass extinction event in Earth's history. Such extinction events not only eliminate species but also their unique evolutionary histories. Here we review the expected loss of Earth's evolutionary history quantified by phylogenetic diversity (PD) and evolutionary distinctiveness (ED) at risk. Due to the general paucity of data, global evolutionary history losses have been predicted for only a few groups, such as mammals, birds, amphibians, plants, corals and fishes. Among these groups, there is now empirical support that extinction threats are clustered on the phylogeny; however this is not always a sufficient condition to cause higher loss of phylogenetic diversity in comparison to a scenario of random extinctions. Extinctions of the most evolutionarily distinct species and the shape of phylogenetic trees are additional factors that can elevate losses of evolutionary history. Consequently, impacts of species extinctions differ among groups and regions, and even if global losses are low within large groups, losses can be high among subgroups or within some regions. Further, we show that PD and ED are poorly protected by current conservation practices. While evolutionary history can be indirectly protected by current conservation schemes, optimizing its preservation requires integrating phylogenetic indices with those that capture rarity and extinction risk. Measures based on PD and ED could bring solutions to conservation issues, however they are still rarely used in practice, probably because the reasons to protect evolutionary history are not clear for practitioners or due to a lack of data. However, important advances have been made in the availability of phylogenetic trees and methods for their construction, as well as assessments of extinction risk. Some challenges remain, and looking forward, research should prioritize the assessment of expected PD and ED loss for more taxonomic groups and test the assumption that preserving ED and PD also protects rare species and ecosystem services. Such research will be useful to inform and guide the conservation of Earth's biodiversity and the services it provides.
地球的进化历史正受到当前第六次大灭绝事件中物种灭绝的威胁。这种灭绝事件不仅消灭了物种，还消灭了它们独特的进化历史。在这里，我们回顾了通过系统发育多样性（PD）和进化独特性（ED）来量化的地球进化历史的预期损失。由于数据普遍缺乏，目前仅对少数几个群体，如哺乳动物、鸟类、两栖动物、植物、珊瑚和鱼类，预测了全球进化历史的损失。在这些群体中，现在有实证支持表明灭绝威胁在系统发育上是聚集的；然而，这并不总是一个充分的条件，与随机灭绝相比，不会导致系统发育多样性的更高损失。最具进化独特性的物种的灭绝和系统发育树的形状是另外两个可以增加进化历史损失的因素。因此，物种灭绝的影响在不同的群体和地区是不同的，即使在大群体中全球损失较低，在子群或某些地区内也可能会有较高的损失。此外，我们还表明，目前的保护实践对 PD 和 ED 的保护很差。虽然进化历史可以通过现有的保护计划间接保护，但要优化其保护，就需要将系统发育指数与那些捕捉稀有性和灭绝风险的指数结合起来。基于 PD 和 ED 的措施可以为保护问题带来解决方案，然而，它们在实践中仍然很少使用，可能是因为保护进化历史的原因对从业人员来说不清楚，或者是由于缺乏数据。然而，在构建系统发育树和方法以及评估灭绝风险方面，已经取得了重要进展。未来仍存在一些挑战，展望未来，研究应优先评估更多分类群的预期 PD 和 ED 损失，并检验保护 ED 和 PD 也保护稀有物种和生态系统服务的假设。这种研究将有助于为保护地球生物多样性及其提供的服务提供信息和指导。
