Department of Animal Ecology and Tropical Biology, Biocenter, Julius-Maximilians-University Würzburg, Würzburg, Germany.
Institute for Ecology and Landscape, Weihenstephan-Triesdorf University of Applied Sciences, Freising, Germany.
PLoS One. 2022 Apr 29;17(4):e0264881. doi: 10.1371/journal.pone.0264881. eCollection 2022.
Arthropod predators are important for ecosystem functioning by providing top-down regulation of insect herbivores. As predator communities and activity are influenced by biotic and abiotic factors on different spatial scales, the strength of top-down regulation ('arthropod predation') is also likely to vary. Understanding the combined effects of potential drivers on arthropod predation is urgently needed with regard to anthropogenic climate and land-use change. In a large-scale study, we recorded arthropod predation rates using artificial caterpillars on 113 plots of open herbaceous vegetation embedded in contrasting habitat types (forest, grassland, arable field, settlement) along climate and land-use gradients in Bavaria, Germany. As potential drivers we included habitat characteristics (habitat type, plant species richness, local mean temperature and mean relative humidity during artificial caterpillar exposure), landscape diversity (0.5-3.0-km, six scales), climate (multi-annual mean temperature, 'MAT') and interactive effects of habitat type with other drivers. We observed no substantial differences in arthropod predation rates between the studied habitat types, related to plant species richness and across the Bavarian-wide climatic gradient, but predation was limited when local mean temperatures were low and tended to decrease towards higher relative humidity. Arthropod predation rates increased towards more diverse landscapes at a 2-km scale. Interactive effects of habitat type with local weather conditions, plant species richness, landscape diversity and MAT were not observed. We conclude that landscape diversity favours high arthropod predation rates in open herbaceous vegetation independent of the dominant habitat in the vicinity. This finding may be harnessed to improve top-down control of herbivores, e.g. agricultural pests, but further research is needed for more specific recommendations on landscape management. The absence of MAT effects suggests that high predation rates may occur independent of moderate increases of MAT in the near future.
节肢动物捕食者通过对昆虫食草动物进行自上而下的调控，对生态系统功能至关重要。由于捕食者群落和活动受到不同空间尺度上的生物和非生物因素的影响，自上而下的调控强度（“节肢动物捕食”）也可能发生变化。考虑到人为引起的气候和土地利用变化，迫切需要了解潜在驱动因素对节肢动物捕食的综合影响。在一项大规模研究中，我们在德国巴伐利亚州沿着气候和土地利用梯度的 113 个开放草本植被斑块上，使用人工毛毛虫记录了节肢动物捕食率，这些斑块嵌入在不同的生境类型（森林、草原、耕地、定居点）中。作为潜在驱动因素，我们包括了生境特征（生境类型、植物物种丰富度、人工毛毛虫暴露期间的局部平均温度和平均相对湿度）、景观多样性（0.5-3.0 公里，六个尺度）、气候（多年平均温度，“MAT”）以及生境类型与其他驱动因素的相互作用。我们没有观察到研究中的生境类型之间、与植物物种丰富度以及整个巴伐利亚气候梯度之间的节肢动物捕食率有实质性差异，但当地平均温度较低时捕食受到限制，并且相对湿度较高时捕食率趋于下降。在 2 公里的尺度上，节肢动物捕食率朝着更加多样化的景观增加。没有观察到生境类型与当地天气条件、植物物种丰富度、景观多样性和 MAT 的相互作用效应。我们的结论是，独立于附近的主要生境，景观多样性有利于开放草本植被中较高的节肢动物捕食率。这一发现可以用来改善对食草动物的自上而下的控制，例如农业害虫，但需要进一步的研究，以提供关于景观管理的更具体建议。MAT 效应的缺失表明，在不久的将来，MAT 的适度增加可能不会导致高捕食率。
