Characteristics of Asian elephant group in Nangunhe National Nature Reserve based on spatio-temporal analysis

Animal grouping is widespread in natural populations, but detecting individual group membership is still in the stage of empirical identification based on photos and videos, without refined technical details. In this study, we examine grouping characteristics of Asian elephants (Elephas maximus) using infrared-triggered camera trapping techniques in Nangunhe National Nature Reserve from November 2022 to May 2023. We deployed 64 camera traps totaling 7 635 effective camera working days. Through meticulous analysis, we identified 255 individually valid photos of Asian elephants and a total of 17 Asian elephants. The capture rates of group and solitary were 18.63% and 16.83% respectively. Through spatial analyses such as distance grouping and correlation, combined with the results of spatial niche overlap, we found that 11 Asian elephants had a high degree of similarity and correlation in their spatial utilization, and formed a group. The spatial activity of two solitaries was highly consistent and formed a small group, while the other solitaries were differentiated. In addition, the activity rhythm data showed that the daily activity rhythm of 11 Asian elephants was highly consistent, and the overall distribution was unimodal. Similarly, the daily activity rhythm of the solitaries highlighted the differences between the small group and the other solitaries. Consequently, the grouping characteristics of the Asian elephants are characterized by a family group of 11 Asian elephants and a small group composed of 2 solitaries, with 4 remaining solitaries. This study fills the research gap in understanding the characteristics of Asian elephant groups in Nangunhe and provides important support for the population management and protection of this species and sympatric species in protected areas.