The effect of past defaunation on ranges, niches, and future biodiversity forecasts
The effect of past defaunation on ranges, niches, and future biodiversity forecasts
复制标题
DOI：
10.1111/gcb.16145
复制
发表时间：
2022-03
影响因子：
11.6
通讯作者：
L. Sales;M. Galetti;A. Carnaval;Sophie Monsarrat;Jens‐Christian Svenning;M. Pires
中科院分区：
文献类型：
--
作者：
L. Sales;M. Galetti;A. Carnaval;Sophie Monsarrat;Jens‐Christian Svenning;M. Pires
人类已经重塑了地球仪上生物多样性的分布，将物种从原本适宜的区域灭绝，并将种群限制在其原始分布范围的一个子集。在这里，我们要问的是，自晚更新世以来，人类活动范围的缩小是否导致了巨型动物的已实现生态位的代表性不足，这是一个象征性的类群，经常被作为恢复行动的目标。使用过去地理分布的重建（即，自然范围）的146个现存的陆生大型（>44公斤）哺乳动物，我们估计他们的气候生态位，如果他们保留了原来的分布和评估其观察到的生态位动态。我们发现，范围收缩导致了几个物种的实现生态位的相当大的代表性不足（即，壁龛未填充）。对于29个物种，超过10%的环境空间曾经看到他们的自然范围已经失去了由于人类活动，至少有12个物种正在经历减少超过50%的实现生态位。18个物种现在可能被限制在低适宜性的位置，那里的适合度和丰度可能会减少;我们认为这些分类群是“气候变化”。对于这些物种来说，如果将目前的次优生境视为未来恢复行动的基线，那么目前的范围所支持的保护战略就有可能被误导。由于大多数基于气候的生物多样性预测完全依赖于当前的发生记录，我们继续测试忽略历史信息对物种潜在分布估计的影响-作为对气候变化敏感性的替代。我们发现，过去的范围收缩驱动的生态位填充导致高估了对未来气候变化的敏感性，导致全球灭绝率高出50%，并低估了未来气候变化下巨型动物保护和恢复的潜力。总之，晚更新世以来的范围收缩也留下了巨大的动物实现气候生态位的印记。因此，由动物群落消失驱动的生态位截断可以直接影响气候和基于栖息地的保护策略。
Humans have reshaped the distribution of biodiversity across the globe, extirpating species from regions otherwise suitable and restricting populations to a subset of their original ranges. Here, we ask if anthropogenic range contractions since the Late Pleistocene led to an under‐representation of the realized niches for megafauna, an emblematic group of taxa often targeted for restoration actions. Using reconstructions of past geographic distributions (i.e., natural ranges) for 146 extant terrestrial large‐bodied (>44 kg) mammals, we estimate their climatic niches as if they had retained their original distributions and evaluate their observed niche dynamics. We found that range contractions led to a sizeable under‐representation of the realized niches of several species (i.e., niche unfilling). For 29 species, more than 10% of the environmental space once seen in their natural ranges has been lost due to anthropogenic activity, with at least 12 species undergoing reductions of more than 50% of their realized niches. Eighteen species may now be confined to low‐suitability locations, where fitness and abundance are likely diminished; we consider these taxa 'climatic refugees'. For those species, conservation strategies supported by current ranges risk being misguided if current, suboptimal habitats are considered baseline for future restoration actions. Because most climate‐based biodiversity forecasts rely exclusively on current occurrence records, we went on to test the effect of neglecting historical information on estimates of species’ potential distribution – as a proxy of sensitivity to climate change. We found that niche unfilling driven by past range contraction leads to an overestimation of sensitivity to future climatic change, resulting in 50% higher rates of global extinction, and underestimating the potential for megafauna conservation and restoration under future climate change. In conclusion, range contractions since the Late Pleistocene have also left imprints on megafauna realized climatic niches. Therefore, niche truncation driven by defaunation can directly affect climate and habitat‐based conservation strategies.