Seasonal home range utilization of Hainan gibbons (Nomascus hainanus) in a secondary tropical forest of Hainan Island, South China

Abstract

The home range utilization of primates reflects their behavioral and ecological strategies to adapt to their environment. However, little is known about the home range behavior of endemic gibbons (Nomascus hainanus) found in a secondary tropical forest of Hainan Island, China. Knowledge of their ranging patterns could contribute to scientific evaluations of the survival risk of this species under habitat conversion. In this study, we analyzed the home range utilization patterns and the seasonal variation of a group of Hainan gibbons in secondary tropical forests in the Bawangling area of National Park of Hainan Tropical Rainforest, using infrared cameras and direct observations. The results show that the annual home area of the gibbon group was 137.4 ha, with no significant difference between the wet and dry seasons. The feeding hotspots of Hainan gibbons are more scattered in the rainy season and more concentrated in the dry season, but not for sleeping hotspots. The relatively small home range suggests that secondary forests may not represent low-quality habitats and thus have a supporting role for the Hainan gibbon population. The widely distributed range of feeding hotspots in the rainy season may be related to the abundance of fruit resources in this season, while gibbons reduce their travel distance and energy expenditure when food is scarce in the dry season. Overall, our findings provide insights into the ecological flexibility of gibbons to seasonal variations in food resources and highlight the conservation value of secondary forests for gibbon populations.