Urgent Conservation Actions Are Needed for Qinling Lenok <i>Brachymystax lenok tsinlingensis</i> Li, 1966: Enlightenment From Model Simulations

The Qinling lenok <i>Brachymystax lenok tsinlingensis</i> Li, 1966, an endemic to China and South Korea, is a rare protected species. Its unique requirements to habitat have made this fish extraordinarily fragile when faced with human pressures and global warming. Hence, predicting and understanding the potential influence of human pressures and global warming on this fish's spatial distribution is quite critical for the conservation and management of the species. To do so, based on its occurrence records and current as well as future environmental dataset, this study constructed a Maximum Entropy (MaxEnt) model for the species to analyze how its potential suitable areas (PSAs) would respond to global warming and human pressures (3 Global Climate Models ×2 Shared Socioeconomic Pathways ×3 future time nodes). The results showed that: (1) the MaxEnt model had strong generalization or transferability ability (AUC > 0.90), was highly reliable to predicting the current and future PSAs of the species; (2) Mean Temperature of Driest Quarter (BIO9), Human Population Density (Pop), Elevation (Elev), and Mean Temperature of Wettest Quarter (BIO8) were the salient environmental factors (given in descending order by significance); (3) the present PSAs for this fish were mainly distributed in Europe, Asia, and North America, and with the intensification of global changes, these areas in all continents would shrink on a large scale, and their distribution centroids would move towards northwest. Based on the above, a series of proposals for conservation and management of the fish were put forward so as to alleviate the loss of this relict species' habitats in the future.