Comparative ecological dynamics of Permian-Triassic communities from the Karoo, Luangwa, and Ruhuhu Basins of southern Africa

The Permian-Triassic mass extinction (PTME) was one of the transformative events of the Phanerozoic, marked by extinction, post-Permian transformation of surviving ecosystems, and the formation of new communities. The South African Karoo Basin has served as the primary source of data on the terrestrial component of these events, but its global applicability remains poorly known. Here, we compare Permian-Triassic communities of the Karoo Basin with those from the Luangwa and Ruhuhu basins of Zambia and Tanzania, respectively, analyzing their functional structures and simulating dynamic responses to environmental perturbation. Results show that compositional similarities of late Permian communities among the basins underlie similarities in their dynamics and resistance to secondary extinction. The Karoo Basin ecosystem also displays evidence of a transformation to increased resistance during the late Permian. Although the Karoo Basin ecosystem was reduced significantly by the PTME, structural features of that resistance persisted into the Early Triassic, facilitated by a greater susceptibility to extinction of small-body-sized amniotes and large carnivorous amniotes. It was undone by the initial stages of postextinction restructuring. Continued evolution of the Triassic ecosystem led to a recovery of resistance, but in a community compositionally dissimilar from its Permian antecedents. Likewise, the upper part of the Lifua Member of the Manda Beds (Middle Triassic) of Tanzania was structurally distinct from the Karoo Basin communities but displayed similar dynamics. The recurrence and convergence of communities with different histories toward similar dynamics suggest that there are taxon-independent norms of community assembly and function operating on geological timescales. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Roopnarine, P. D., K. D. Angielczyk, S. Olroyd, S. J. Nesbitt, J. Botha-Brink, B. R. Peecook, M. O. Day, and R. M. H. Smith. 2018. Comparative ecological dynamics of Permian-Triassic communities from the Karoo, Luangwa, and Ruhuhu basins of southern Africa; pp. 254–272 in C. A. Sidor and S. J. Nesbitt (eds.), Vertebrate and Climatic Evolution in the Triassic Rift Basins of Tanzania and Zambia. Society of Vertebrate Paleontology Memoir 17. Journal of Vertebrate Paleontology 37(6, Supplement).

二叠纪-三叠纪大灭绝事件（Permian-Triassic mass extinction, PTME）是显生宙（Phanerozoic）最具变革意义的地质事件之一，其核心特征包括全球性生物大规模灭绝、幸存生态系统在二叠纪后的转型以及全新生物群落的形成。
南非卡鲁盆地（Karoo Basin）是这类陆地灭绝事件研究的核心数据来源，但其研究结论的全球适用性仍未得到充分认知。
本研究对比了卡鲁盆地与赞比亚卢安瓜盆地（Luangwa Basin）、坦桑尼亚鲁胡胡盆地（Ruhuhu Basin）的二叠纪-三叠纪群落，分别分析其功能结构，并模拟群落对环境扰动的动态响应。
研究结果显示，各盆地晚二叠世群落的组成相似性，是其生态动态与抗二次灭绝能力相似的基础。卡鲁盆地生态系统还表现出晚二叠世期间抗扰动能力逐步提升的证据。
尽管二叠纪-三叠纪大灭绝事件显著削弱了卡鲁盆地的生态系统，但其原有的抗扰动结构特征仍延续至早三叠世，这一过程得益于小型羊膜动物（amniotes）与大型肉食性羊膜动物更高的灭绝易感性。该生态系统最终在灭绝后重建的初始阶段彻底瓦解。
三叠纪生态系统的持续演化推动了抗扰动能力的恢复，但其群落组成已与二叠纪祖先群落截然不同。
同样，坦桑尼亚曼达地层（Manda Beds）利富亚段（Lifua Member）的上部地层（中三叠世），其群落结构与卡鲁盆地群落存在显著差异，但动态特征却高度相似。
具有不同演化历史的群落反复出现并趋同至相似的动态特征，这表明在地质时间尺度上，存在不依赖类群的群落组装与功能运行范式。
补充材料——本文补充材料可通过www.tandfonline.com/UJVP免费获取。
本文引用格式：Roopnarine P D, Angielczyk K D, Olroyd S, Nesbitt S J, Botha-Brink J, Peecook B R, Day M O, Smith R M H. 2018. 南非南部卡鲁、卢安瓜与鲁胡胡盆地二叠纪-三叠纪群落的比较生态动力学//Sidor C A, Nesbitt S J (eds.). 《坦桑尼亚与赞比亚三叠纪裂谷盆地的脊椎动物与气候演化》. 古脊椎动物学会（Society of Vertebrate Paleontology）专论17. 《脊椎动物古生物学杂志》（Journal of Vertebrate Paleontology）, 37(6, 增刊): 254–272.