Climatic and environmental changes, as well as human action, have been cited as potential causes for the extinction of megafauna in South America at the end of the Pleistocene. Among megamammals lineages with Holarctic origin, only horses and proboscideans went extinct in South America during this period. This study aims to understand how the spatial extent of habitats suitable for Equus neogeus and Notiomastodon platensis changed between the last glacial maximum (LGM) and the middle Holocene in order to determine the impact that climatic and environmental changes had on these taxa. We used species distribution modeling to estimate their potential extent on the continent and found that both species occupied arid and semiarid open lands during the LGM, mainly in the Pampean region of Argentina, southern and northeastern Brazil, and parts of the Andes. However, when climate conditions changed from dry and cold during the LGM to humid and warm during the middle Holocene, the areas suitable for these taxa were reduced dramatically. These results support the hypothesis that climatic changes were a driving cause of extinction of these megamammals in South America, although we cannot rule out the impact of human actions or other potential causes for their extinction.

中文翻译：

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物种分布模型揭示了南美洲已灭绝巨型动物的生态位

气候和环境变化以及人类活动被认为是更新世末期南美洲巨型动物灭绝的潜在原因。在北极起源的巨型哺乳动物谱系中，在此期间，只有马和长鼻类动物在南美洲灭绝了。本研究旨在了解栖息地的空间范围如何适合新马和Notiomastodon platensis在末次盛冰期（LGM）和全新世中期之间发生了变化，以确定气候和环境变化对这些分类群的影响。我们使用物种分布模型来估计它们在大陆上的潜在范围，发现这两种物种在 LGM 期间都占据了干旱和半干旱的开阔土地，主要位于阿根廷的 Pampean 地区、巴西南部和东北部以及安第斯山脉的部分地区。然而，当气候条件从 LGM 期间的干燥和寒冷转变为全新世中期的潮湿和温暖时，适合这些类群的区域急剧减少。这些结果支持气候变化是南美洲这些巨型哺乳动物灭绝的驱动原因的假设，尽管我们不能排除人类行为的影响或其他潜在原因导致它们灭绝的可能性。