Ant Species Assembly in Constructed Grasslands

1. Agri-environmental incentive programmes encourage conversionof marginal agricultural land to grasslands to reduce soil erosion and supportbiodiversity of native flora and fauna. Most grassland animals colonise theseconstructed habitats as propagules from the surrounding landscape. Ants areslow to colonise and rely on resources within the patch, making them valuableas indicators of disturbance and recovery.2. We studied how ant species diversity and composition are structured bypatch and landscape variation of grasslands in Ohio, USA. Ant communitieswere collected from 23 constructed grasslands differing in area, age, vegetation,soils, management and surrounding land cover. We analysed trap frequency for14 species that varied in habitat specialisation to identify species responses topatch- and landscape-level predictors.3. Grassland age and soil texture determined ant species richness and communitycomposition. Trap frequency analysis showed contrasting speciesresponses to patch and landscape characteristics: habitat specialists were moreabundant in older, larger patches with more surrounding grassland, while disturbance-tolerantspecies were more frequent in younger patches surrounded byintensive agriculture. Habitat generalists and open habitat species included avariety of patch- and landscape-level factors in best models.4. Ant community assembly in constructed grasslands is shaped by time andphysical characteristics at the patch-level, but the surrounding landscape acts asa filter for the colonising community. Our findings support the use of ants asecosystem recovery indicators following disturbance in agricultural landscapes,but show that shifts in species composition are better indicators of grasslandhabitat variation than ant richness