Spatiotemporal variation of anthropogenic drivers predicts the distribution dynamics of Hainan gibbon

Understanding the historical causes of species endangerment is vital, yet difficult. The Hainan gibbon Nomascus hainanus has declined in numbers dramatically in the last century, resulting in a single population on Hainan Island in China. The lack of historical surveys has limited our understanding of habitat requirements and habitat loss, impeding an evidence-based approach to the conservation management of this species. Here, we used a variety of data sources, including literature, surveys, and expert experience, to reconstruct the historical distribution of Hainan gibbons and used a species distribution model (SDM) to predict suitable habitats in the 1950 s, 1970 s, and the 2010 s. We found that four anthropogenic drivers, namely human disturbance and habitat transformation, natural forest cover, landscape shape index, and distance to the nearest roads, played important roles in the distribution of the species (sum of their permutation importance >50%). The SDM based on earlier occurrences (1950 s) identified more suitable habitats than the model using recent data (1970 s), which supported the shifting and shrinking of the realised niche, as revealed by the probability density curves and niche hypervolumes. In addition, 89.29% of the distribution of Hainan gibbons revealed by historical occurrences was lost between the 1950 s and 2010 s, which was much faster than the habitat loss predicted by the SDM using the 1950 s (49.62%) or the 1970 s data (78.21%). Moreover, we recorded 108 individuals of Hainan gibbons harvested from the 1950 s to the 1980 s, of which 87.96% were hunted in the 1960 s, indicating severe damage to this species. Our study highlights the critical importance of using historical data to reconstruct the habitat requirements of species. We also suggest that spatially explicit habitat recovery and strict elimination of human disturbances should be undertaken in the Hainan Tropical Forest National Park, and corridors should be developed among isolated habitat patches to restore this species.

Automated summary

Understanding the historical causes of species endangerment is vital, yet difficult. The Hainan gibbon Nomascus hainanus has experienced a severe decline in population, with only one population remaining on Hainan Island, China. Lack of historical surveys has hindered the effective conservation management of this species. This study utilizes various data sources to reconstruct the historical distribution of Hainan gibbons and predicts suitable habitats using a species distribution model. The findings highlight the importance of historical data in understanding habitat requirements and emphasize the need for habitat recovery and elimination of human disturbances to preserve this endangered species.