Abstract Understanding how regional ecosystems respond to sea‐level and environmental perturbations is a main challenge in palaeoecology. Here we use quantitative abundance estimates, integrated within a sequence stratigraphic and environmental framework, to reconstruct benthic community changes through the 13 myr history of the Jurassic Sundance Seaway in the western United States. Sundance Seaway communities are notable for their low richness and high dominance relative to most areas globally in the Jurassic, and this probably reflects steep temperature and salinity gradients along the 2000 km length of the Seaway that hindered colonization of species from the open ocean. Ordination of samples shows a main turnover event at the Middle–Upper Jurassic transition, which coincided with a shift from carbonate to siliciclastic depositional systems in the Seaway, probably initiated by northward drift from subtropical latitudes to more humid temperate latitudes, and possibly global cooling. Turnover was not uniform across the onshore–offshore gradient, but was higher in offshore environments. The higher resilience of onshore communities to third‐order sea‐level fluctuations and to the change from a carbonate to a siliciclastic system was driven by a few abundant eurytopic species that persisted from the opening to the closing of the Seaway. Lower stability in offshore facies was instead controlled by the presence of more volatile stenotopic species. Such increased onshore stability in community composition contrasts with the well‐documented onshore increase in taxonomic turnover rates, and this study underscores how ecological analyses of relative abundance may contrast with taxonomically based analyses. We also demonstrate the importance of a stratigraphic palaeobiological approach to reconstructing the links between environmental and faunal gradients, and how their evolution through time produces local stratigraphic changes in community composition.

中文翻译：

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短寿命航道对海平面和气候变化的动物群响应：美国西部内陆侏罗纪

摘要 了解区域生态系统如何响应海平面和环境扰动是古生态学的主要挑战。在这里，我们使用在序列地层和环境框架内整合的定量丰度估计，通过美国西部侏罗纪圣丹斯海道 13 年的历史重建底栖群落变化。相对于侏罗纪全球大部分地区，圣丹斯海道群落以其低丰富度和高优势而著称，这可能反映了沿海道 2000 公里长的陡峭温度和盐度梯度，阻碍了公海物种的殖民。样本排序显示了中上侏罗统过渡时期的主要周转事件，这与 Seaway 的碳酸盐岩沉积系统向硅质碎屑沉积系统的转变相吻合，这可能是由从亚热带纬度向更潮湿的温带纬度向北漂移以及可能是全球变冷引起的。陆上-海上梯度的周转率并不均匀，但在海上环境中更高。陆上群落对三阶海平面波动和从碳酸盐岩到硅质碎屑岩系统的变化具有较高的恢复力，这是由一些丰富的广域物种驱动的，这些物种从海道的开放到关闭一直存在。近海相中较低的稳定性反而受到更易挥发的狭窄物种的存在的控制。这种增加的陆上群落组成稳定性与陆上分类周转率的增加形成鲜明对比，这项研究强调了相对丰度的生态分析如何与基于分类的分析形成对比。我们还展示了地层古生物学方法对重建环境和动物群梯度之间联系的重要性，以及它们随时间的演变如何产生群落组成的局部地层变化。