First dispersal records of the endangered Banteng (Bos javanicus) in Thung Yai Naresuan West Wildlife Sanctuary, Thailand

Banteng (Bos javanicus) is listed as an endangered species because of a global population decline of at least 50% over the last 25 years. The Western Forest Complex (WEFCOM) of Thailand has been identified as a priority site for banteng population recovery, and Huai Kha Keang Wildlife Sanctuary (HKK) is the most important source site for this species within the WEFCOM. We have provided evidence and discussed banteng dispersal from HKK to Thung Yai Naresuan West Wildlife Sanctuary (TYW). We sampled an area of 147 km2 in banteng habitat next to the border between HKK and TYW using camera traps. We divided the sampled area into four grid cells and placed camera traps during January to December 2022. We setup the camera traps near saltlicks and natural water sources, as important resources for banteng, to maximize capture probability. In total, 2,835 trap days were obtained. Bantengs were captured in all seasons (RAI=1.66), especially in dry dipterocarp forest, which contains the ground forage availability for banteng, and the low-slope area with elevation 600–700 m adjacent to the border between HKK and TYW. The results highlighted that banteng, which had never been reported in TYW before, appeared there for the first time. They most likely dispersed from the population source in HKK and settled in a habitat that is considered suitable for them. The habitat management and protection are significant for the future recovery of banteng populations in the TYW and the rest of protected areas in the WEFCOM.

Methods
A camera-trapping survey was conducted to study banteng habitat use in Thung Yai Naresuan West Wildlife Sanctuary from January to December 2022. We sampled 147 km2 surrounding their habitat and divided the area into four grid cells of 7 × 7 km per grid cell, following the banteng home range of 49 km2 in Thailand (Prayurasiddhi, 1997) (Figure 1). Each large grid cell was further divided into four 3.5 x 3.5 km grid cells for camera trap spacing and placement to investigate banteng habitat use. For camera trap placement, we took into account the factors influencing banteng distribution and intensity of habitat use, especially near saltlicks and water sources, in order to maximizing capture probability (Suksavate et al., 2022; Thapa et al., 2019). We set camera traps at 33 locations using a combination of the camera trap models Bushnell DS-4K and Spartan E4GB2, which were the main camera traps used in this study (Figure 1). Camera traps were placed 40–60 cm above the ground and set up along ridges, saltlicks, water sources, and wildlife trails (Silver et al., 2004; Suksavate et al., 2022). For data interpretation and analysis, we considered consecutive photos with a time interval of more than 30 min as new photographic events (O'Brien et al., 2003; Rahman, 2019; Saisamorn et al., 2019). Banteng age class classification was defined for individuals in each capture event as adult (> 3-years old), juvenile (1–3 year-olds), or calf (< 1 years old), based on the body shape and size (Phoonjampa et al., 2021).