Abstract Frequent extreme weather events, which jeopardize agriculture by affecting crop health, characterize the ongoing climate change. Temporary patches where sown plants are poorly developed (hereafter “field defects”) are likely to increase with climate change and can be colonized by other plant species. Although perennial non-crop habitats can act as refuges for beneficial insects in agricultural landscapes and increase ecosystem services (ESs) in neighbouring arable fields, the relevance of field defects is unknown. Here, we quantified two ESs (pest and weed seed predation) in field defects within oilseed rape crops and related the ES levels with the activity-density of ground beetles and temperature. In 10 fields, we used artificial caterpillars made of plasticine and seed cards of two weed species (Taraxacum sp. and Stellaria sp.) to quantify the ESs in two sampling periods (spring and summer) and three habitat types: field defects, crops grown in standard conditions (field interiors) and crop-defect boundaries. Ground beetles were sampled using pitfall traps and classified into feeding guilds and body-size classes. Insects and mammals were the main pest predators, and predation increased in summer but did not differ among habitats. Seed predation rates for both species were significantly higher in summer. Predation upon Taraxacum seeds was higher in the field interiors, whereas the predation rate upon Stellaria seeds was significantly higher in the field interiors and defects compared to that in the crop-defect boundaries. The predation rate by insects increased with the activity-density of the medium- and large-sized carnivorous carabids, whereas the seed predation rate for both weed species was positively related to the activity-density of medium-sized herbivorous carabids. Finally, the mean and maximum temperatures were negatively linked to the predation rates on artificial caterpillars and seeds of Taraxacum, respectively. Our results suggest that these ephemeral habitats are not related to a strong decrease in ecosystem services; thus, field defects may not cause substantial changes in ES provisioning. We confirmed that ground beetles are important providers of both investigated ESs and showed that microclimatic conditions might play an important role in the regulation of ESs in agroecosystems.

中文翻译：

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油菜田内生态系统服务的分布：田间缺陷对害虫和杂草种子捕食率的影响

摘要 频繁的极端天气事件通过影响作物健康危及农业，是持续气候变化的特征。播种的植物发育不良的临时斑块（以下称为“田间缺陷”）可能会随着气候变化而增加，并可能被其他植物物种定殖。尽管多年生非作物栖息地可以作为农业景观中益虫的避难所，并增加邻近耕地的生态系统服务 (ES)，但田间缺陷的相关性尚不清楚。在这里，我们量化了油菜作物田间缺陷中的两种 ES（害虫和杂草种子捕食），并将 ES 水平与地甲虫的活动密度和温度相关联。在 10 个田地中，我们使用了由橡皮泥制成的人造毛虫和两种杂草（蒲公英属和繁缕属）的种子卡。) 量化两个采样期（春季和夏季）和三种栖息地类型的 ES：田间缺陷、在标准条件下生长的作物（田间内部）和作物缺陷边界。使用陷阱陷阱对地面甲虫进行采样，并将其分为饲养行会和体型级别。昆虫和哺乳动物是主要的害虫捕食者，夏季捕食增加，但栖息地之间没有差异。两种物种的种子捕食率在夏季都显着更高。与作物缺陷边界相比，田间内部对蒲公英种子的捕食率较高，而田间内部和缺陷处对繁缕种子的捕食率显着较高。昆虫的捕食率随着中大型食肉动物的活动密度的增加而增加，而两种杂草的种子捕食率与中型食草动物的活动密度呈正相关。最后，平均温度和最高温度分别与人工毛虫和蒲公英种子的捕食率呈负相关。我们的研究结果表明，这些短暂的栖息地与生态系统服务的大幅减少无关；因此，现场缺陷可能不会导致 ES 配置的实质性变化。我们证实地面甲虫是所研究的两种 ES 的重要提供者，并表明小气候条件可能在农业生态系统中 ES 的调节中发挥重要作用。平均温度和最高温度分别与人工毛虫和蒲公英种子的捕食率呈负相关。我们的研究结果表明，这些短暂的栖息地与生态系统服务的大幅减少无关；因此，现场缺陷可能不会导致 ES 配置的实质性变化。我们证实地面甲虫是所研究的两种 ES 的重要提供者，并表明小气候条件可能在农业生态系统中 ES 的调节中发挥重要作用。平均温度和最高温度分别与人工毛虫和蒲公英种子的捕食率呈负相关。我们的研究结果表明，这些短暂的栖息地与生态系统服务的大幅减少无关；因此，现场缺陷可能不会导致 ES 配置的实质性变化。我们证实地面甲虫是所研究的两种 ES 的重要提供者，并表明小气候条件可能在农业生态系统中 ES 的调节中发挥重要作用。