Population ecology and herd dynamics of blue bull Boselaphus tragocamelus in forest and agrarian lands of district Ludhiana Punjab.

Abstract

Blue bull (Boselaphus tragocamelus) is one of the largest antelope species and native to the Indian subcontinent. The blue bull population is surplus in some Indian states, and has attained pest status. The information regarding animal population ecology helps in understanding the ecosystem health, climate change impact and plays a pivotal role in devising conservation policies, mitigating human-animal conflict, and resource management. Herd size and composition of blue bull were recorded in forest and agrarian lands of district Ludhiana. Scan sampling method was used to record data during 24 fortnightly visits in 30 clusters from June 2022 to May 2023. The mapping of the blue bull population density highlights the critical spots of animal density. Its population density and encounter rate ranged from 0.318 to 5.79 animals/km² and 0.145-1.316 animals/km respectively. The herd composition (χ2 = 167.9396, P = < 0.0001, df = 15) and animals of different age groups and sexes (χ2 = 69.7284, P = < 0.0001, df = 20) changed significantly with season. The habitat types, forest and agrarian land, had no effect on the herd composition. Non-harem groups were observed in summer and monsoon, while harem groups were observed throughout autumn, pre-winter, winter, and spring, indicating long breeding season. The overall sex ratio adult female to adult male ratio is 1:0.18, skewed towards females, indicating the potential for population growth over time. Calving events were most prominent during the pre-winter season. Animal sightings and group size fluctuations were found to be closely correlated with extrinsic factors like food and shelter availability. This study marks the first comprehensive exploration of blue bull population ecology in agrarian land in Punjab and can provide valuable insights for policymakers to focus on managing blue bull populations in areas with high density, particularly during critical breeding seasons, to prevent overpopulation and mitigate human-animal conflicts. Additionally, strategies should be developed to ensure the preservation of their natural habitat.