Temporal variation in ant community assemblages along a rural–urban gradient in the Yaoundé metropolis, Cameroon

Abstract

Urbanization is one of the most lasting anthropogenic disturbances threatening native species diversity including ants. Ants play important ecological functions such as seed dispersal, biological pest control, and bio-indicators of environmental changes. Herein, we investigated and tracked ant communities in three sites (rural, suburban and urban) in 2007 and resampled the same categories ten years after, using the same methods. A total of 39 species belonging to 7 subfamilies and 19 genera was recorded during the two sampling periods. During the 10-year study period, ant species richness declined in sites that were rural in 2007, but suburban in 2017. However, ant species richness increased between 2007 and 2017 in sites that were suburban and urban in 2007, and urban sites in 2017. In contrast, ant abundance increased significantly within all sites over time. Six tramp species were found in different sites with Wasmannia auropunctata and Pheidole megacephala being the most common species between 2007 and 2017 respectively. Tramp species represented more than a half of all ant fauna at each sampling period and their abundance increased by 55% between 2007 and 2017. These results indicate changes in ant community composition and highlight explosion of some tramp species with urbanization over longer temporal scales. This study also demonstrates that the rapid transformation of suburban and rural areas into built environments leads to the replacement of native species by disturbance specialists in urbanized areas over time. The suburban peak in species numbers suggests that edge effects may influence the diversity and composition of ant species along urbanization gradients. Further research is needed to understand the ecological processes shaping the ant community in areas with intermediate levels of disturbance.