Results-based agri-environmental schemes can reflect habitat integrity for a non-target taxonomic group: Carabidae

Results-based agri-environment schemes are emerging as a valuable tool to incentivise optimal management of farmed habitats for biodiversity targets. Results-based payment schemes in Ireland use multicriteria assessments to score habitat integrity for specific targets, linking outcomes to farmer payments. Habitat integrity for a specific target is expected to have indirect co-benefits for wider farmland biodiversity. However, we lack an understanding of how results-based payment scheme assessments relate to other bioindicators of habitat integrity. Our research focuses on a results-based payment scheme which incentivises better terrestrial habitat integrity with the aim of improving watercourse quality. We explore the relationship between non-target carabid beetles, vascular plants and the results-based payment scheme's multicriteria habitat assessment. It was anticipated that carabid beetle communities would reflect the results-based payment scheme's definition of habitat integrity across the range of scores. Pitfall trapping for carabid beetles and vegetation surveys were carried out in 19 peatland and 18 wet grassland plots, categorised into high, medium, and low habitat integrity using the scores assigned by the results-based payment scheme. We found that the results-based payment scheme's multicriteria assessment broadly reflects habitat integrity for non-target carabid beetles in peatlands and grasslands. Eurytopic and disturbance tolerant species showed a greater association with low and medium scoring plots. Higher scoring plots supported greater diversity, with intact peatland being particularly important for hygrophilous specialists. Synthesis and application: Results-based payment scheme's multicriteria assessments have co-benefits at plotlevel for non-target carabid beetles and incentivising optimal management can have positive conservation outcomes for this group. Inclusion of hydrological result indicators where relevant in results-based payment scheme assessments is recommended to reward wider biodiversity. Carabids are suitable as monitoring taxa where hydrological functioning is a results-based payment scheme priority.