4.3 Synthesis and applications
Our findings show that newly established grasslands can increase ant species richness, abundance and pest control in agroecosystems, but also indicate that it takes longer than three years to maintain biodiversity level functions that are comparable to old semi-natural grasslands. To counteract the loss of important biodiversity functions, agricultural management should take into account key strategies for ecological enhancement (Bommarco, Kleijn, & Potts, 2013; Perović et al., 2018) and consider the replacement of harmful measures.
Our findings illustrate that new grasslands should be integrated into a long-term management strategy for the promotion and resilience of yield-enhancing ecosystem services provided by ants. Firstly, a turnover of newly established grasslands back into crop fields inevitably destroys initiated ant colonies, disrupts ant community succession and dramatically reduces arthropod populations that deliver key biocontrol services (Ganser, Knop, & Albrecht, 2019). Secondly, a long-term establishment of new grasslands is paramount to promote not only ubiquitous ant species in their abundance but also habitat specialists with longer colonization times (Dauber & Wolters, 2005), in account of the fact that only a broad diversity of functional insurance species can guarantee the resilience of biological control services in European agroecosystems (Tscharntke et al., 2005). Our findings suggest that newly established grasslands represent a promising measure for enhancing agricultural landscapes, but must be preserved in the longer term to allow comprehensive immigration of ant species into habitats that support agricultural biodiversity and functionality.