Ants Indicate Urbanization Pressure in Sacred Groves of Southwest India:A Pilot Study

Sacred groves may contain remnants of pristine and primary forests outside the state-owned protected area system. As they are small fragments and located in the neighbourhood of human settlements, towns, and cities, they are likely to be affected by urbanization. We studied the effect of urbanization on the ecosystem health of sacred groves of Kerala using litterdwelling ants as the indicator taxa. Ants were pitfalltrapped (10-12 traps/sacred grove) from three rural and two urban sacred groves, and identified to species. Overall, 1,119 ants of 32 species and 6 subfamilies (Aenictinae, Dolichoderinae, Ectatomminae, Formicinae, Myrmicinae and Ponerinae) were collected. This corresponds to 76.54% of the estimated species richness. Urbanization had little impact on the species diversity of ants. Abundance was remarkably high in urban sacred groves, mainly due to higher abundance of generalist and invasive species. The effect of urbanization was indicated by different ant assemblages. Rural sacred groves had nine species and three subfamilies exclusive to them as against the five exclusive species of urban sacred groves. Urban sacred groves were characterized by high abundance of Anoplolepis gracilipes, a globally important invasive species. Sacred groves were clustered based on the rural-urban gradient as hypothesized by the study.