Urbanisation and habitat fragmentation favour thermophilic and monogynous ant species

Environmental changes such as urbanisation and habitat fragmentation profoundly impact ecological communities. We investigated the response of ant communities to urbanisation and habitat fragmentation in the Paris region, comparing urban parks vs rural forests outside the city. We found a clear difference in species composition between urban and rural environments, with a higher prevalence of monogynous and thermophilic species in the city. Forest communities are homogeneous across the three fragmentation levels we studied, i.e. seem little impacted by fragmentation, while park communities differ noticeably depending on park size, with larger parks harbouring more species. Our findings suggest that urbanisation selects specific ant traits favouring more thermophilic species, thereby increasing the mean thermal preference of urban communities. Such selective effects constrain spatial dynamics at the metacommunity level, with important implications for their maintenance in a climate change context.