The climate after the largest mass extinction so far 252 million years ago was cool, later very warm and then cool again. Thanks to the cooler temperatures, the diversity of marine fauna（动物群） ballooned, as paleontologists from the University of Zurich have reconstructed. The warmer climate, coupled with a high CO2 level in the atmosphere, initially gave rise to new, short-lived species. In the longer term, however, this climate change had an adverse effect on biodiversity and caused species to become extinct. Until now, it was always assumed that it took flora and fauna（动植物） a long time to recover from the vast mass extinction at the end of the Permian geological period 252 million years ago. According to the scientific consensus, complex ecological communities only began to reappear in the Middle Triassic, so 247 million years ago. Now, however, a Swiss team headed by paleontologist Hugo Bucher from the University of Zurich reveals that marine animal groups such as ammonoids（菊石类） and conodonts（牙形石） (microfossils) already peaked three or four million years earlier, namely still during the Early Triassic.

The scientists chart the temperature curves in detail in Nature Geoscience, demonstrating that the climate and the carbon dioxide level in the atmosphere fluctuated greatly during the Early Triassic and what impact this had on marine biodiversity and terrestrial plants.