In the Anthropocene, the ranges of introduced species are expanding, while extinction-prone species are contracting. Introductions and extinctions are caused by how species respond to human impacts, but it is unknown why the ranges of some species expand and some contract. Here, we test whether this opposite response of human impact is due to introduced and extinction-prone species falling at opposite ends of geographic, evolutionary, or ecological trait continua. We constructed a database of native range maps, traits, phylogenetic relationships, and the introduction and extinction-prone status of squamate reptiles with ranges native to the Western Hemisphere. Across > 3000 snake and lizard species (88% of known native squamates), 142 had been introduced elsewhere and 483 were extinction-prone (i.e. vulnerable, endangered, critically endangered, extinct in the wild, extinct). To explain variation in status, we first tested if the same human-impacted regions in the Americas contained the native ranges of species of either status. Second, we tested for phylogenetic signal in species status. Finally, we tested the explanatory power of multiple trait continua. The native ranges of introduced and extinction-prone reptiles were clustered in island regions with high human impact versus mainland regions with lower human impact. Phylogenetic signal was weak for status, but introduced and extinction-prone species were clustered in different clades. All geographic and ecological traits that explained each status supported the opposite ends hypothesis. Introduced species had larger, edgier ranges, while extinction-prone species had smaller, simpler ranges. Introduced species were mostly herbivorous/omnivorous, while extinction-prone species were mostly carnivorous. Introduced species produced larger clutches, while extinction-prone species had smaller body sizes. In the Anthropocene, the native ranges of introduced and extinction-prone species are in the same human-impacted regions where trait continua, having opposite effects, determine whether species ranges expand or contract in the continuing face of global change.

中文翻译：

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人类对岛屿的影响加大，增加了本土岛屿爬行动物的引入和灭绝状况


在人类世，引进物种的范围正在扩大，而易灭绝物种的范围正在缩小。物种的引入和灭绝是由物种对人类影响的反应引起的，但目前尚不清楚为什么某些物种的范围扩大而另一些物种的范围缩小。在这里，我们测试了人类影响的这种相反反应是否是由于引入的物种和易于灭绝的物种落在地理、进化或生态特征连续体的两端所致。我们构建了一个数据库，其中包含西半球原生范围的有鳞爬行动物的原生范围图、特征、系统发育关系以及引入和灭绝倾向状态。在超过 3000 种蛇和蜥蜴物种（已知本地有鳞动物的 88%）中，142 种已被引入其他地方，483 种有灭绝倾向（即脆弱、濒危、极度濒危、野外灭绝、灭绝）。为了解释状况的变化，我们首先测试了美洲受人类影响的同一地区是否包含这两种状况的物种的原生范围。其次，我们测试了物种状态的系统发育信号。最后，我们测试了多性状连续体的解释力。引进和濒临灭绝的爬行动物的原生地集中在人类影响较大的岛屿地区，而大陆地区则集中在人类影响较小的地区。系统发育信号的状态较弱，但引入的物种和易灭绝的物种聚集在不同的进化枝中。所有解释每种状态的地理和生态特征都支持相反的假设。引进物种的范围更大、更尖锐，而易灭绝物种的范围更小、更简单。引进物种大多为草食/杂食性，而易灭绝物种则大多为肉食性。 引入的物种产生了更大的窝，而易于灭绝的物种则体型较小。在人类世，引进物种和易灭绝物种的原生范围位于同一受人类影响的地区，在这些地区，具有相反影响的性状连续体决定了物种范围在持续的全球变化中是扩大还是缩小。