Ant species assembly in constructed grasslands is structured at patch and landscape levels

Abstract

Agri‐environmental incentive programmes encourage conversion of marginal agricultural land to grasslands to reduce soil erosion and support biodiversity of native flora and fauna. Most grassland animals colonise these constructed habitats as propagules from the surrounding landscape. Ants are slow to colonise and rely on resources within the patch, making them valuable as indicators of disturbance and recovery. We studied how ant species diversity and composition are structured by patch and landscape variation of grasslands in Ohio, USA. Ant communities were collected from 23 constructed grasslands differing in area, age, vegetation, soils, management and surrounding land cover. We analysed trap frequency for 14 species that varied in habitat specialisation to identify species responses to patch‐ and landscape‐level predictors. Grassland age and soil texture determined ant species richness and community composition. Trap frequency analysis showed contrasting species responses to patch and landscape characteristics: habitat specialists were more abundant in older, larger patches with more surrounding grassland, while disturbance‐tolerant species were more frequent in younger patches surrounded by intensive agriculture. Habitat generalists and open habitat species included a variety of patch‐ and landscape‐level factors in best models. Ant community assembly in constructed grasslands is shaped by time and physical characteristics at the patch‐level, but the surrounding landscape acts as a filter for the colonising community. Our findings support the use of ants as ecosystem recovery indicators following disturbance in agricultural landscapes, but show that shifts in species composition are better indicators of grassland habitat variation than ant richness.

Ant diversity in Neotropical savannas: Hierarchical processes acting at multiple spatial scales

“…Soil properties may also condition ant abundance and diversity at the community level. For instance, lower abundance and smaller ant species number were found in soils with high clay content both in temperate grasslands (Boulton et al, ; Campbell & Crist, ) and in tropical savannas (Andersen et al, ), a phenomenon which appears to be related to limitations in nest excavation. In fact, it has been suggested that the local assembly of ant communities is conditioned by processes operating at the establishment phase, when ant propagules (founding queens) colonize new areas and compete for nesting sites (Andersen, ; Hakala, Seppä, & Helanterä, ).…”

Environmental drivers of ant species richness and composition across the Argentine Pampas grassland

“…Pitfall trapping is widely used to sample epigeal arthropods (Delsinne et al . ; Szewczyk & Mccain ; Campbell & Crist ), and provides a good representation of ant communities in open grassland ecosystems (Andersen ; Melbourne ).…”

“…). Highly degraded grasslands such as the Pampean region need urgent programs to encourage reconversion of selected agricultural lands, and ants have been suggested as grassland recovery indicator (Campbell & Crist ). We ask whether ant diversity spatial pattern at the regional scale is mainly determined by temperature, productivity or environmental heterogeneity.…”

Reducing Native Ant Abundance Decreases Predation Rates in Midwestern Grasslands

“…In contrast, interest in using perennial grasses in bioenergy cropping systems (Landis et al 2018, Robertson et al 2017) could increase their occurrence in Midwestern landscapes with important implications for ants (Kim et al 2017) and other beneficial insects (Werling et al 2011a, Werling et al 2014). The addition of even relatively small patches of grasslands can harbor generalist predatory ant species like L. neoniger (Campbell and Crist 2017), and increasing the number of patches within a landscape may improve ant species diversity (Dauber et al 2005) and functional diversity (Crist 2009). To improve our ability to maximize ecosystem services in human-managed landscapes, future work exploring the role of land use change on ecological processes should consider ants as numerically dominant and effective predators in grasslands.…”