Sanctuary in the City: Urban Monkeys Buffered against Catastrophic Die-off during ENSO-related Drought

Large-scale climatic drivers such as El Niño Southern Oscillation (ENSO) can overwhelm factors that ordinarily govern local population dynamics. We recently documented an ENSO-related die-off of mammals in the Kumbhalgarh Wildlife Sanctuary (KWS), Rajasthan, India. This die-off coincided with the La Niña-induced drought of 2000, which followed two consecutive monsoon failures. Hanuman langurs suffered a population crash of nearly 50% from 1999 to 2001. A Multivariate ENSO Index explained 80% of the variability in population size during the time series, and predicted the mass mortality and/or recruitment failure associated with the major La Niña event spanning 1999. Here, we ask whether langurs in a large Rajasthani city, Jodhpur, were buffered against drought because humans provisioned them with food—for religious reasons. Unlike the KWS population, the Jodhpur population suffered no significant decline. In 2001, this urban population remained 95% as large as in 1999, before the drought. Variability in population size was also vastly reduced in Jodhpur. Thus, the impact of drought was dampened in a major urban area compared with an officially protected area. In this case, high human population density was not anathema for conservation. Wildlife sanctuaries in protected areas are undeniably important conservation tools, but our findings reinforce the notion that cities can serve as de facto sanctuaries for some species. This study provides some hope for biodiversity conservation in a rapidly urbanizing world, particularly for holy and commensal species.