Detecting Range Shrinking From Historical Amphibian Species Occurrences Under Influence of Human Impacts: A Case Study Using the Chinese Giant Salamander, .

Amphibian declines, driven by climate change (e.g., shifting temperatures, altered precipitation) and human activities like deforestation, agriculture, and urbanization, may lead to local extinctions. Quantifying the relative impact of climate change versus human influence remains challenging. This study uses species distribution models (SDMs) and nearly 1000 years of historical distribution data from ancient texts and local archives to reconstruct the past distribution range of the Chinese giant salamander () and to assess the spatiotemporal shifts in its range over time. The results reveal that over the past millennium, the potential distribution range of the Chinese giant salamander consistently contracted, decreasing by 10% from the Ming Dynasty (1368-1644) to the Qing Dynasty (1644-1912) and a further 30% from the Qing Dynasty to the modern era. Losses are concentrated in eastern plains with abundant water bodies, resulting in available habitat reduction to 27% of the Qing Dynasty's area. Climate factors have been key in shaping the salamander's distribution, but our findings reveal that population density has consistently impacted its range throughout history, highlighting the lasting influence of human activity. Climate models project a about 10% decrease in suitable habitat by around 2090, with northward shifts in suitable habitat. Given the urgent threat of habitat loss and environmental degradation, immediate and effective actions are crucial to prevent the local extinction of the Chinese giant salamander, including habitat protection, environmental restoration, and strict regulations against hunting and habitat destruction. This study, analyzing the Chinese giant salamander's suitable habitat historically, identifies human activities as a pivotal force in early amphibian species decline in China, contributing valuable perspectives to future amphibian conservation and management.