Lizards of the Thar Desert – Resource partitioning and community composition

• First study on resource partitioning in the Thar Desert lizard community.
• Spatial overlap low across habitats, moderate within habitats.
• Species showed finer separation through differential spatial use of same areas.
• Diurnal species showed peaks of activity at different times of the day.
• This study confirms space as an important niche dimension facilitating coexistence within desert lizard communities.

How similar species co-exist in nature is a fundamental question in community ecology. Resource partitioning has been studied in desert lizard communities across four continents, but data from South Asia is lacking. We used area-constrained visual encounter surveys to study community composition and spatial and temporal resource partitioning in a lizard community during summer in the Thar Desert, western India, addressing an important biogeographic gap in knowledge. Twelve one-hectare grids divided into 25 m × 25 m plots were placed across four habitats – barren dunes, stabilized dunes, grassland, and rocky hills. We recorded 1039 sightings of 12 species during 84 sampling sessions. Lizard abundance decreased in the order stabilized dunes > grassland > barren dunes > rocky hills; richness was in roughly the opposite order. Resource partitioning was examined for the seven commonest species. Overall spatial overlap was low (<0.6) between species pairs. Overlap was higher within habitats, but species showed finer separation through use of different microhabitat categories and specific spatial resources, as well as by positioning at different distances to vegetation. Diurnal species were also separated by peak time of activity. Space appears to be an important resource dimension facilitating co-existence in this desert lizard community.