Upland grassland habitats and agri-environment schemes change soil microarthropod abundance.
Agricultural intensification is a major driver of biodiversity loss, with the implementation of Agri-Environment Schemes (AESs) being a widespread policy designed to prevent further loss, and to maintain or restore ecosystem health. Upland grassland soils are disproportionately impacted by intensification including drainage, artificial fertiliser use, compaction and erosion while the effect of AES management on below-ground microarthropods, which mediate a range of ecosystem processes, is largely unknown. This study tested the effects of AES management of upland grasslands on microarthropod communities using a large-scale factorial field experiment. The study focused on microarthropods with distinct taxa-specific responses observed. Oribatid mite abundance was associated with wetter, more extensive pastures with native grasses characteristic of semi-improved grassland managed by AESs, whereas Collembola abundance was associated with drier, more intense, reseeded (Lolium perenne dominated) pastures characteristic of conventionally managed improved grasslands. Differences in taxa responses may be driven by life-history traits and resilience to disturbance. There was no net effect of management, habitat or their interaction on total microarthropod family diversity or abundance. Synthesis and Applications. Results from this study suggest that in floristically simple upland agroecosystems the impact of agri-environment measures on below-ground soil biota are context-dependent (differing between contrasting grassland types), and taxa-specific, rather than leading to general increases in biodiversity per se, and the responses of soil microarthropods are driven by environmental variation caused by overall management of grassland fields. Measures should aim to increase the availability of areas of semi-improved grassland, with native plant mixtures, adjacent to improved grasslands, to maximise the habitats available to soil microarthropods.