Data from: Agri-environmental schemes promote ground-dwelling predators in adjacent oilseed rape fields: diversity, species traits and distance-decay functions

1. Rising demands for agricultural products and high environmental costs of intensive agriculture reinforce the need for ecological replacements in agricultural management. In Europe, agri-environmental schemes (AES) are implemented to enhance species richness and provision of ecosystem services, but the effectiveness of different AES types and the spatial extent of possible beneficial effects are little understood. In this study we assessed the effects of different AES types on diversity, species traits and distance-decay functions of ground- dwelling predators in adjacent crop fields. 2. On 31 study sites with winter oilseed rape (OSR) adjacent to four types of AES differing in management intensity and habitat age we recorded ground-dwelling predators (carabid beetles, staphylinid beetles and spiders) during OSR growth from April to July. Effects of the AES on species richness, activity densities and different traits of these taxa were examined with transects of pitfall traps running along a continuous distance gradient from the AES across the habitat border into the OSR fields. 3. Ground-dwelling predator communities benefitted similarly from the different AES types. In adjacent OSR, activity densities, carabid species richness and the proportion of predatory carabid beetles declined from the field edge while mean body size increased. Adjacent AES increased the proportion of predatory species and simultaneously decreased the proportion of granivorous or frugivorous species in adjacent OSR fields. 4. Synthesis and applications. Our results indicate a beneficial effect of adjacent agri-environmental schemes (AES) on ground-dwelling predators in oilseed rape (OSR), mostly irrespective of AES type and therefore management intensity and habitat age. The short-ranged distance decay effects on natural enemies in OSR underpin that a strategic spatial placement of AES in agricultural landscapes is required to maximise biological pest control. This could help replace anthropogenic input in modern agriculture and secure adequate yields.

1. 农产品需求持续攀升，加之集约化农业带来的高昂环境成本，愈发凸显了农业管理中生态替代方案的必要性。在欧洲，农业环境计划（agri-environmental schemes, AES）旨在提升物种丰富度与生态系统服务供给，但目前学界对不同类型AES的实施效果，以及其潜在有益效应的空间覆盖范围仍知之甚少。本研究针对毗邻农田的地表捕食性类群，探究了不同类型AES对其多样性、物种性状及距离衰减函数的影响。
2. 本研究选取了31处研究样地，每处样地均设置了管理强度与生境年龄存在差异的4类AES，且毗邻冬油菜（winter oilseed rape, OSR）田块。于4月至7月的冬油菜生长期内，调查了样地内的地表捕食性类群——包括步甲科甲虫、隐翅甲科甲虫与蜘蛛。通过沿从AES跨越生境边界直至冬油菜田块的连续距离梯度布设的陷阱诱捕器样带，分析了AES对上述类群的物种丰富度、活动密度及各类物种性状的影响。
3. 不同类型的AES对地表捕食性群落的增益效果相近。在毗邻的冬油菜田块中，捕食者的活动密度、步甲物种丰富度以及捕食性步甲的占比均随距田块边缘的距离增加而降低，而平均体型则随之升高。毗邻的AES可提升冬油菜田块内捕食性物种的占比，同时降低食籽或食果物种的占比。
4. 综合与应用。本研究结果表明，毗邻的农业环境计划（AES）对冬油菜田块内的地表捕食性类群具有有益效应，且该效应基本不受AES类型、管理强度与生境年龄的影响。冬油菜田内天敌对AES的短程距离衰减效应证实，需在农业景观中对AES进行战略性空间布局，以最大化生物害虫防治的效果。该策略可助力替代现代农业中的人为投入，保障作物稳产丰产。