Globally, owing to rapid urbanization and unregulated garbage or resource management in cities, free-ranging dogs (FRD) are on the rise. This has led to an increase in FRD-borne zoonotic diseases worldwide. Bangalore is one of the fastest-growing cities in India, where we studied the spatial and temporal distribution of free-ranging dogs (FRDs) over a period of two years (2018, 2019) to understand if and how resource distribution and dispersion drives group size and home-range size in FRD in a peri-urban landscape. The resource-dispersion hypothesis (or RDH) suggests that when resources are distributed heterogeneously across space and/or time, several individuals may share them over common territories without imposing costs to one another. RDH has three main assumptions and although in most previous studies only one assumption have been met, it has never been tested in a peri-urban ecosystem. In one of the busiest bus stops in peri-urban Bangalore, we delineated an area of 4 sq. km to estimate the FRD population using a four-sample method of photographic mark-recapture. We collected geospatial data, along with information on age, sex, coat coloration, body conditions, etc. Furthermore, information on discernable resources was recorded within this area. Spatial maps of FRD and resource distributions were generated using QGIS. The study was repeated for two consecutive years.
Results/Conclusions
Free-ranging dog population varied from 262 ± 12.7 to 322 ± 15.7 in 2018 and from 152 ± 7.3 to 163 ± 10.9 in 2019 in summer and winter seasons respectively. Male-female sex ratios were also similar in two years, but with a slight increase in the two seasons (1.15 in summer and 1.37 in winter), displaying estrous cycle in these dogs during winter months. We found that the spatial distribution of FRDs and resources within the study area were strongly correlated in both seasons across the years consistently (p < 0.0001). Tests for RDH indicated that in a peri-urban system the assumptions of RDH were only partially satisfied, where patch dispersion was correlated to home range size only in winter, but not summer. Although the reason for this is not clear, it could be due to extreme heterogeneity in resource distribution patterns over space and time. This was probably due to the spatial and temporal complexities of resource distribution and unregulated garbage management in these urbanscapes.