Roost site selection and seasonal dynamics of the Indian flying fox (Pteropus medius): Influence of environmental and anthropogenic factors
Abstract
This study examines the roosting site selection and seasonal dynamics of the Indian flying fox ( Pteropus medius Te m minck, 1825) in relation to environmental and anthropogenic factors. Fifteen roosting sites located in Okara, Kasur and Lahore districts , Punjab, Pakistan were investigated over a two-year period from July 2022 to June 2024. A total of 202 trees were used by P . medius as roosting sites representing 28 species, 23 genera and 10 families. Roosting sites with higher bat populations were dominated by Bombax ceiba (16.3%), Eucalyptus sp. (9.9%), and Pinus strobus (8.4%) during winter whereas Syzygium cumini (7.9%), Swietenia mahagoni (6.4%) and Ficus benjamina (6.4%) were more frequently occupied during summer. Significant seasonal fluctuations in bat numbers were observed with protected sites showing minimal changes while non-protected sites had higher bat populations in winter. Protected areas, such as Changa Manga Forest provided more stable env i ronmental conditions, leading to higher and more stable bat populations. The correlation matrix revealed that permanent roos t ing sites were more strongly associated with higher bat populations. Additionally, bat abundance was positively correlated with canopy cover (r = 0.499), tree diameter at breast height (r = 0.501) and tree height (r = 0.122). Principal component analysis (PCA) highlighted temperature, humidity, and vegetation as key environmental factors influencing roost site selection. The analysis also revealed that anthropogenic activities such as tree cutting and hunting negatively affect bat populations. Accor d ing to PCA, protected permanent roosts in natural habitats with minimum human interference scored highest followed by pe r manent protected sites in urban areas, with temporary non-protected sites scoring lowest. A 1.7% decline in bat numbers was recorded over the study period, particularly at non-protected sites due to human-induced disturbances. The findings highlighted the critical need for conservation of roosting habitats, particularly in light of the ongoing threats posed by human activities and climate change.References
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