Finding the green in differently disturbed forests under different weather conditions: detection and occupancy of the green pit viper Trimeresurus (Cryptelytrops) macrops at the Sakaerat Biosphere Reserve, Thailand

Abstract

The response of venomous snakes to anthropogenic landscape disturbance remains scarcely studied in tropical regions. Green pit vipers are among the most diverse venomous snakes in the Southeast Asian tropics and bite the highest number of people of any group of venomous snakes where they are found, yet conservation and snakebite management efforts have been hindered by limited prior studies of these organisms in both natural and anthropogenically disturbed landscapes. Subsequently, we sought to address key knowledge gaps regarding the persistence and response of green pit vipers to anthropogenic disturbance. Utilizing repeated field surveys coupled with remote sensing landscape feature data, we fit single-season Bayesian occupancy models to investigate the potential influences of weather variables on detection and various landscape features on the persistence of the big-eyed pit viper (Trimeresurus (Cryptelytrops) macrops). Temperature and humidity marginally positively influenced detection. The probability of T. macrops occupancy increased with increasing distance to buildings and houses, roads, water, and increased canopy height and elevation but decreased with increasing distance to the core zone of the reserve, natural forest, and if a site was a plantation. Our findings suggest that anthropogenic landscape disturbance influences the presence of T. macrops within a biosphere reserve in Thailand, contrary to the general perception that the species is resilient to land-use change. We strongly suggest further study of the green pit viper response to human disturbance, which would significantly benefit conservation and snakebite management plans for these diverse organisms.