The late Quaternary in North America was marked by highly variable climate and considerable biodiversity loss including a megafaunal extinction event at the terminal Pleistocene. Here, we focus on changes in body size and diet in Neotoma (woodrats) in response to these ecological perturbations using the fossil record from the Edwards Plateau (Texas) across the past 20,000 years. Body mass was estimated using measurements of fossil teeth and diet was quantified using stable isotope analysis of carbon and nitrogen from fossil bone collagen. Prior to ca. 7000 cal yr BP, maximum mass was positively correlated to precipitation and negatively correlated to temperature. Independently, mass was negatively correlated to community composition, becoming more similar to modern over time. Neotoma diet in the Pleistocene was primarily sourced from C3 plants, but became progressively more reliant on C4 (and potentially CAM) plants through the Holocene. Decreasing population mass and higher C4/CAM consumption was associated with a transition from a mesic to xeric landscape. Our results suggest that Neotoma responded to climatic variability during the terminal Pleistocene through changes in body size, while changes in resource availability during the Holocene likely led to shifts in the relative abundance of different Neotoma species in the community.

中文翻译：

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Neotoma对第四纪晚期气候变化和生物多样性丧失的敏感性

北美第四纪晚期的特点是气候变化很大，生物多样性丧失相当大，包括更新世末期的巨型动物灭绝事件。在这里，我们专注于体型和饮食的变化新生儿瘤（woodrats）使用过去 20,000 年爱德华兹高原（德克萨斯州）的化石记录来应对这些生态扰动。使用化石牙齿的测量来估计体重，并使用来自化石骨胶原蛋白的碳和氮的稳定同位素分析来量化饮食。在大约之前。7000 cal yr BP，最大质量与降水呈正相关，与温度呈负相关。独立地，质量与社区组成呈负相关，随着时间的推移变得更类似于现代。新生儿瘤更新世的饮食主要来自 C3植物，但逐渐变得更加依赖 C4（以及潜在的 CAM）植物通过全新世。减少人口质量和更高的 C4/CAM 消费与从 meic 到 xeric 的转变有关。我们的结果表明新生儿瘤通过体型的变化来响应更新世末期的气候变化，而全新世期间资源可用性的变化可能导致不同物种的相对丰度发生变化新生儿瘤社区中的物种。