Ecological dynamics of terrestrial and freshwater ecosystems across three mid-Phanerozoic mass extinctions from northwest China

Abstract

The Earth has been beset by many crises during its history, and yet comparing the ecological impacts of these mass extinctions has been difficult. Key questions concern the kinds of species that go extinct and survive, how communities rebuild in the post-extinction recovery phase, and especially how the scaling of events affects these processes. Here, we explore ecological impacts of terrestrial and freshwater ecosystems in three mass extinctions through the mid-Phanerozoic, a span of 121 million years (295–174 Ma). This critical duration encompasses the largest mass extinction of all time, the Permian–Triassic (P–Tr) and is flanked by two smaller crises, the Guadalupian–Lopingian (G–L) and Triassic–Jurassic (T–J) mass extinctions. Palaeocommunity dynamics modelling of 14 terrestrial and freshwater communities through a long sedimentary succession from the lower Permian to the lower Jurassic in northern Xinjiang, northwest China, shows that the P–Tr mass extinction differed from the other two in two ways: (i) ecological recovery from this extinction was prolonged and the three post-extinction communities in the Early Triassic showed low stability and highly variable and unpredictable responses to perturbation primarily following the huge losses of species, guilds and trophic space; and (ii) the G–L and T–J extinctions were each preceded by low-stability communities, but post-extinction recovery was rapid. Our results confirm the uniqueness of the P–Tr mass extinction and shed light on the trophic structure and ecological dynamics of terrestrial and freshwater ecosystems across the three mid-Phanerozoic extinctions, and how complex communities respond to environmental stress and how communities recovered after the crisis. Comparisons with the coeval communities from the Karoo Basin, South Africa show that geographically and compositionally different communities of terrestrial ecosystems were affected in much the same way by the P–Tr extinction.

Extinction cascades, community collapse, and recovery across a Mesozoic hyperthermal event

“…This pattern of densely connected, species-poor communities of opportunists/generalists is consistent with evidence from palaeoecological interpretations of the fossil record (i.e. low-diversity/high-abundance communities of opportunistic species) 34,37 and other instable post-mass extinction food webs reconstructed from the fossil record 18,19,50 .…”

Late Palaeozoic‐Mesozoic palaeontology and stratigraphy in China: A tribute to the achievements of Professor Zhuoting Liao

“…Clearly, the discordant views on the latter two topics still exist, and the debates also continue. However, it is Liao's original data and initiative notions that sparked our current studies and new models on biotic extinction and subsequent recovery in terrestrial ecosystems over the P‐Tr transition (Y. G. Huang et al, 2021) as well as mineral and hydrocarbon explorations in the vast regions of Central Asia.…”

“…The P‐Tr boundary sections record abundant vertebrate fossils. Y. G. Huang, Chen, et al (2021) modelled the collapse and rebuilding of terrestrial ecosystem resilience across the P‐Tr extinction based on terrestrial fossil records from these areas, and the authors revealed that terrestrial ecosystems were rather fragile in the aftermath of the P‐Tr extinction, and their resilience did not recover until late Middle Triassic. Wan et al (2021) describe a new silicified coniferous trunk, Zhuotingoxylon liaoi from the uppermost part of Guodikeng Formation in the Tuha Basin, Xinjiang, providing insights into vascular plant diversity prior to the P‐Tr extinction.…”

A unique early Triassic (Spathian) conodont community from the Nanzhang‐Yuan'an Fauna, Hubei Province, South China

“…High sea surface temperatures (Joachimski et al, 2012;Sun et al, 2012), anoxia (Song et al, 2012;Huang et al, 2016;Metcalfe et al, 2015), increased terrestrial input into the ocean (Algeo and Twichett, 2010;Dudás et al, 2017;Song et al, 2015;Georgiev et al, 2020) and abnormal productivity (Grasby et al, 2016;Luo et al, 2011;Meyer et al, 2011) were thought to have played some critical roles during both the mass extinction and the recovery. Except for those environmental or extrinsic factors, biological or intrinsic factors have also played important roles during these two processes (Feng et al, 2022;Hautmann et al, 2015;Hofmann et al, 2015;Huang et al, 2021).…”