Multi-species productive grasslands offer advantages over permanent grasslands for arthropod conservation, but preserving semi-natural grasslands remains essential

Abstract

Grasslands support high diversity of arthropods, but agricultural intensification has driven widespread declines. Multi-species productive grasslands (MSPG), a recently developed grassland type combining high yields with increased plant-species diversity, may offer benefits for arthropod conservation. We assessed their value relative to semi-natural grasslands (SNGs) and permanent grasslands (PG), focusing on pollinators and key arthropod orders, and evaluated the effects of land-use intensity (LUI) and plant-species richness (PSR). We used a randomized complete block design with 36 grasslands (12 per treatment) on sandy soils in the Netherlands. Pollinators were measured using transect counts, and arthropods with pyramid traps and DNA metabarcoding. LUI and PSR were quantified per site. Pollinator abundance was highest in SNGs, intermediate in MSPGs and lowest in PGs. Alpha diversity was higher in both SNG and MSPGs than in PGs, while beta and gamma diversity were substantially higher in SNGs. Pollinator abundance and richness decreased with LUI and increased with PSR. Arthropod responses were order-specific: Diptera and Coleoptera were more associated with MSPGs and PGs, showing positive associations with high LUI and low PSR. In contrast, Araneae, Lepidoptera and Hemiptera were more associated with SNGs, showing negative associations with high LUI and low PSR. Although total alpha diversity did not differ between grassland types, beta and gamma diversity were highest in SNGs. Synthesis and applications. SNGs remain irreplaceable for arthropod conservation, supporting the highest gamma diversity and providing habitat for species sensitive to high LUI. They should be regarded as the cornerstone of arthropod conservation in agricultural landscapes. MSPGs represent an improved alternative to PGs, particularly by enhancing floral resources, although their value could be substantially improved by reducing LUI. Our findings provide clear guidance for grassland management and policy: protect and restore SNGs, promote MSPGs over PGs and lower LUI of grasslands.