Conservation Science Group, Department of Zoology, University of Cambridge, Cambridge, United Kingdom.
BirdLife International, Cambridge, United Kingdom.
PLoS One. 2021 May 19;16(5):e0249633. doi: 10.1371/journal.pone.0249633. eCollection 2021.
Climate change is having profound effects on the distributions of species globally. Trait-based assessments predict that specialist and range-restricted species are among those most likely to be at risk of extinction from such changes. Understanding individual species' responses to climate change is therefore critical for informing conservation planning. We use an established Species Distribution Modelling (SDM) protocol to describe the curious range-restriction of the globally threatened White-tailed Swallow (Hirundo megaensis) to a small area in southern Ethiopia. We find that, across a range of modelling approaches, the distribution of this species is well described by two climatic variables, maximum temperature and dry season precipitation. These same two variables have been previously found to limit the distribution of the unrelated but closely sympatric Ethiopian Bush-crow (Zavattariornis stresemanni). We project the future climatic suitability for both species under a range of climate scenarios and modelling approaches. Both species are at severe risk of extinction within the next half century, as the climate in 68-84% (for the swallow) and 90-100% (for the bush-crow) of their current ranges is predicted to become unsuitable. Intensive conservation measures, such as assisted migration and captive-breeding, may be the only options available to safeguard these two species. Their projected disappearance in the wild offers an opportunity to test the reliability of SDMs for predicting the fate of wild species. Monitoring future changes in the distribution and abundance of the bush-crow is particularly tractable because its nests are conspicuous and visible over large distances.
气候变化正在对全球物种的分布产生深远影响。基于特征的评估预测，专业物种和分布范围有限的物种最有可能因这些变化而灭绝。因此，了解单个物种对气候变化的反应对于指导保护规划至关重要。我们使用一种成熟的物种分布模型 (SDM) 协议来描述全球受威胁的白尾燕（Hirundo megaensis）在埃塞俄比亚南部一个小地区的奇特分布范围。我们发现，在各种建模方法中，该物种的分布很好地由两个气候变量描述，即最高温度和旱季降水。这两个变量之前也被发现限制了与白尾燕无关但密切共生的埃塞俄比亚 Bush-crow（Zavattariornis stresemanni）的分布。我们根据一系列气候情景和建模方法来预测这两个物种未来的气候适宜性。由于这两个物种在其当前分布范围内的 68-84%（对于燕子）和 90-100%（对于 Bush-crow）的气候预计将变得不适宜，它们在未来半个世纪内极有可能灭绝。密集的保护措施，如协助迁移和圈养繁殖，可能是保护这两个物种的唯一选择。它们在野外的预期消失为测试 SDM 预测野生物种命运的可靠性提供了机会。监测 Bush-crow 未来的分布和数量变化尤其具有可操作性，因为它的巢非常显眼，在很大范围内都可以看到。
