Differences in Habitat Quality Drive Behavioral Contrasts in Two Family Groups of the Critically Endangered Hainan Gibbon (Nomascus hainanus).

Understanding how spatiotemporal habitat variability shapes endangered species' behavior is crucial for effective conservation. This study examined the impact of fine-scale habitat variation on four behavioral patterns (feeding, resting, social, and traveling) of the critically endangered Hainan gibbon. Year-round behavior data were collected from two groups: GC inhabiting an area with abundant food resources, and GE in a secondary forest with sparse resources. Using 135 monitoring plots, we analyzed variation in 27 habitat variables categorized into food, nutrients, plant diversity, safety and stability, and topography. Linear models revealed crown height, food plant abundance, and crude fat as key variables shaping behaviors. Higher community plant and food plant richness significantly enhanced feeding frequency, while steeper slopes increased traveling. Habitat quality variation shaped distinct behavioral strategies: in GC, feeding and resting were primarily influenced by food, social behavior by safety and stability, and traveling by plant diversity. In GE, resting, social, and traveling behaviors were mainly driven by topography, while feeding was influenced by nutrients. Likewise, food variables dominated during the dry season, whereas safety and stability, and topography variables were more important in the wet season. This study provides the first analysis of Hainan gibbons' behavioral strategies linked to fine-scale habitat variability and seasonal dynamics. The findings highlight the importance of protecting diverse habitats, as different Hainan gibbon groups exhibit distinct behavioral adaptations to their varying resource availability. This underscores the need for habitat-specific primate conservation and management in fragmented landscapes.