Habitat use and distribution of nile monitors (Varanus niloticus) in a mosaic of land use types and human population densities in KwaZulu-Natal, South Africa

ContextGlobally, with the continuous increase in human populations, unprecedented changes in land use are taking place. Little is known about how African reptiles respond to this rapid land use change.ObjectivesWe used sightings to establish if Nile monitors (Varanus niloticus) are persisting in a mosaic of human population densities and land use types in KwaZulu-Natal Province, South Africa.MethodsWe collected sighting data throughout KwaZulu-Natal between April 2022 and July 2023, using three main methods, namely urban sightings obtained from reptile relocation groups and collaborations with reptile relocators; sightings obtained from personal encounters and citizen scientist observations using social media,s posters, newspaper articles and interviews; and sightings from iNaturalist observations.ResultsWe obtained and used 419 sightings and then identified two hotspot areas in the province on which we chose to focus. Site A was dominated by natural habitat, and anthropogenic land use types dominated site B. We found a significant relative selection strength for most tested land covers over anthropogenic cover in site A, whereas most were insignificant in site B. Our results suggest that the use of anthropogenic land use types by Nile monitors in KwaZulu-Natal may be driven by habitat transformation and loss. Nile monitors were found persisting in urban mosaic landscapes and, when compared with available cover, were found in increasingly wooded (natural and urban vegetation) areas with increased human populations. Furthermore, they used small anthropogenic water bodies (e.g., swimming pools and storm drains), making them less reliant on rivers in urban environments. Their population demographics were similar in low and high human population density, but there appeared to be a skew towards smaller and younger individuals in medium human population density areas. Reproduction was occurring successfully in urban environments, but the detection of larger monitors by potential wild and domestic predators and negative human interactions pose risks. Our study outlined the importance of natural and managed (e.g., gardens, parks, golf courses) green spaces in urban mosaic landscapes for wildlife persistence, specifically Nile monitors, and supporting human well-being as well as reptile conservation. There is an overall need for more research on this highly exploited yet understudied reptilian urban adapter.