The effects of sensitive environmental indicators in interpreting faunas of the past: a case study from the Jurassic of China

The Yanliao Biota is a key Mesozoic terrestrial Lagerstätte in China. It is dominated by invertebrates, particularly clam shrimp, water boatmen and mosquitoes. Vertebrates are rare, with occasional sturgeons and salamanders. Most Chinese researchers suggest that there may be a spatiotemporal and physical association between fragmentation and erosion of the North China Craton (NCC) circumscribing the evolution of the Middle Jurassic Yanliao and Early Cretaceous Jehol faunas that are separated by c . 40 million years. However, recent research has primarily focused on the broad relationships between the tectonic behaviour of the North China Craton and events involving biodiversity and macroevolutionary expansion of these faunas whilst simultaneously neglecting quantitative analyses of community structure and the effects of environmental factors. By integrating species abundances and community co‐occurrence networks with geochemical data, we identified salinity as being strongly associated with differentiation among the fossil communities of the Early Yanliao fauna during the late Middle Jurassic interval. Furthermore, our results ruled out humidity, temperature, water carbon‐to‐nitrogen ratio, and water oxidation conditions as factors with strong correlations, indirectly reinforcing the hypothesis that structural alteration of the North China Craton significantly influenced development and extinction of the Yanliao biota.