Agricultural intensification is among the major threats to farmland biodiversity and associated ecosystem services. Agri-environment schemes in Europe aim to counteract the continuous decrease of permanent grassland habitat and related decline of biodiversity in agricultural landscapes. We established new grasslands adjacent to permanent old grasslands to study effects on arthropod pollinators and predators. Over three years, we assessed the effects of newly established grasslands on activity density, species richness and assemblages of pollinators (syrphids, bumblebees, solitary bees) and ground-dwelling predatory arthropods (carabids, spiders, ants). Pollinator activity density and species richness of all three pollinator groups approximately doubled in newly established grasslands compared to old grasslands, indicating suitability of new grasslands as pollinator feeding habitat. Predator responses were less consistent. Species richness and activity density of carabids and ants did not increase in new grasslands, indicating slower adaptation to new habitats. Spider activity density increased in the newly established grasslands and in adjacent cereal fields, but no significant differences in species richness compared to old grasslands were observed. Bumblebees and solitary bees showed distinct distance decays in cereal fields. Syrphid activity density declined in cereal fields far away from the newly established grasslands, but not nearby. Carabids increased and ants decreased in species richness and activity density with increasing distance from old grasslands in cereal fields and newly established grasslands alike. In contrast, spider species richness and activity density decreased with increasing distance from old grasslands in cereal fields only, but there was no distance decay in newly established grasslands. While pollinators utilized the additional floral resources within the whole area of newly established grassland quickly, predators reacted much slower. Even after three years, there was no measurable response of carabid and ant activity density and only a minor response of spiders. This clearly shows that short-term measures are not sufficient to sustainably conserve farmland biodiversity. The conservation of permanent grassland and landscape heterogeneity should be prioritized. However, the restoration of new grassland should also be encouraged by agri-environment schemes as a supplement, to enhance functional biodiversity in agricultural landscapes.

农业集约化是农田生物多样性和相关生态系统服务的主要威胁之一。欧洲的农业环境计划旨在抵消永久草原栖息地的持续减少和农业景观中生物多样性的相关下降。我们在永久性旧草原附近建立了新草原，以研究对节肢动物传粉者和捕食者的影响。三年多来，我们评估了新建立的草原对活动密度、物种丰富度和传粉媒介（食蚜蝇、大黄蜂、独蜂）和陆栖掠食性节肢动物（carabids、蜘蛛、蚂蚁）的影响。与旧草地相比，新建立的草地中所有三个传粉媒介群体的传粉媒介活动密度和物种丰富度大约翻了一番，表明新草原适合作为传粉媒介觅食栖息地。捕食者的反应不太一致。在新的草原上，甲虫和蚂蚁的物种丰富度和活动密度没有增加，表明对新栖息地的适应较慢。新建立的草原和邻近的谷地中的蜘蛛活动密度增加，但与旧草原相比，物种丰富度没有显着差异。大黄蜂和独居蜜蜂在麦田中表现出明显的距离衰减。在远离新建立的草原但不在附近的麦田中，蚜虫的活动密度下降。随着距谷田老草地和新建立草地的距离增加，甲虫增加，蚂蚁的物种丰富度和活动密度下降。相比之下，仅在谷田中，蜘蛛物种丰富度和活动密度随着与老草地距离的增加而降低，而在新建立的草地中，距离没有衰减。虽然传粉者很快利用了整个新建草地区域内的额外花卉资源，但捕食者的反应要慢得多。即使在三年之后，也没有可测量的甲虫和蚂蚁活动密度的反应，而蜘蛛只有轻微的反应。这清楚地表明，短期措施不足以可持续地保护农田生物多样性。优先保护永久性草地和景观异质性。然而，新草地的恢复也应以农业环境计划为补充，以增强农业景观中的功能生物多样性。