Geographical distributions and ecological ranges of the dominant snail species in China and their palaeoclimatic implications

Fossil land snails in aeolian sediments are useful for reconstructing past environments, but quantitative knowledge about their geographical and climatic distribution is limited. We conducted a systematic survey of snails in 402 surface soil samples from China, spanning the climatic range from cold temperate to subtropical. The dominant snail species include Vallonia tenera, Gastrocopta armigerella, Pupilla aeoli, Cathaica richthofeni, Punctum orphana, Opeas striatissimum, and Macrochlamys angigyra. Using the Maximum Entropy model, we determined the geographical distribution of individual species. M. angigyra and O. striatissimum are abundant mainly in warm-temperate and subtropical regions, while P. aeoli and V. tenera occurred mainly in semi-arid regions. Quantitative estimates of the optimal climatic parameters and tolerance ranges for the snail species were obtained using weighted averaging. Cold aridiphilous species like V. tenera (MAT: ∼5.1–12.5 °C, MAP: ∼400–640 mm) and P. aeoli (∼6.2–10.9 °C, ∼390–580 mm) demonstrate greater adaptability and tolerance to lower temperatures compared to the thermo-humidiphilous M. angigyra (∼10.0–15.8 °C, ∼500–1100 mm), and O. striatissimum (∼9.9–15.3 °C, ∼490–960 mm). These quantitative climate ranges and geographical distributions can be applied to Quaternary snails in China to accurately quantify past climates.