Data from: Landscape composition, configuration, and trophic interactions shape arthropod communities in rice agroecosystems

1. Increasing landscape heterogeneity of agroecosystems can enhance natural enemy populations and promote biological control. However, little is known about the multi-scale effects of landscape heterogeneity on arthropod communities in rice agroecosystems, especially in combination with trophic interactions.
2. We examined for the first time how landscape heterogeneity, measured by four independent metrics of landscape composition and configuration at three spatial scales, affected species abundance and species richness of rice arthropods within four functional groups and the abundance of the most common species at 28 sites in the Philippines. We additionally examined the influence of trophic interactions among these functional groups.
3. We found that both the compositional and configurational landscape heterogeneity in combination with trophic interactions determine the structure of rice-arthropod communities. Herbivore abundance decreased with increasing landscape diversity. The abundance of parasitoids and species richness of both parasitoids and predators increased with the structural connectivity of rice bunds. Fragmentation of the rice landscape had a clear negative effect on most arthropod groups, with the exception of highly mobile predatory arthropods. Abundance of common predators and detritivore species decreased with increasing complexity in the shape of rice patches.
4. Trophic interactions, measured as the abundance of prey, outweighed the importance of landscape heterogeneity for predators. In contrast, parasitoids responded positively to configurational landscape heterogeneity but were unaffected by prey abundance.
5. Synthesis and applications. Landscape heterogeneity and trophic interactions had different effects on different functional groups. While predator abundance was solely driven by the availability of prey, all other functional groups in the rice-arthropod community were significantly affected by the composition and configuration of surrounding landscape features. Landscape management aiming to improve biodiversity and biological pest control in rice agroecosystems should promote a diversity of land uses and habitat types within 100–300 m radii to reduce the presence of pests. Management practices should also focus on maintaining smaller rice patches and the structural connectivity of rice bunds to enhance populations of the natural enemies of rice pests. Future research should focus on the temporal and spatial manipulation of rice fields to maximize the effects of biological control.12-Jun-2018

1. 农业生态系统（agroecosystems）的景观异质性提升，可增强天敌种群数量并促进生物防治。然而，目前针对水稻农业生态系统中景观异质性对节肢动物（arthropod）群落的多尺度效应，尤其是结合营养级互作（trophic interactions）的相关研究仍较为匮乏。
2. 本研究首次以菲律宾28个采样点为研究对象，通过三个空间尺度下的4项独立景观组成与构型（landscape composition and configuration）指标量化景观异质性，探究其对4个功能群（functional groups）内水稻节肢动物的物种多度（species abundance）、物种丰富度（species richness），以及优势物种多度的影响。此外，本研究还分析了这些功能群间的营养级互作效应。
3. 研究结果表明，景观组成异质性、景观构型异质性与营养级互作共同决定了水稻节肢动物群落的结构。植食性动物（herbivore）的多度随景观多样性提升而降低；寄生性天敌（parasitoids）的多度，以及寄生性天敌与捕食性天敌（predators）的物种丰富度，均随水稻田埂（rice bunds）的结构连通性增强而升高。水稻景观的破碎化对多数节肢动物类群具有显著负面效应，但移动能力极强的捕食性节肢动物除外。常见捕食性天敌与食腐动物（detritivore）的多度，随水稻田块形状复杂度提升而降低。
4. 对于捕食性天敌而言，以猎物多度表征的营养级互作的重要性超过了景观异质性。与之相反，寄生性天敌对景观构型异质性呈正向响应，但不受猎物多度的影响。
5. 总结与应用
景观异质性与营养级互作对不同功能群的影响存在差异。捕食性天敌的多度仅由猎物可获得性决定，而水稻节肢动物群落中的其余所有功能群，均显著受周边景观要素的组成与构型影响。旨在提升水稻农业生态系统生物多样性与害虫生物防治效果的景观管理策略，应在半径100~300米范围内推广多样化的土地利用方式与生境类型，以降低害虫种群规模。同时，管理实践需注重维持小型水稻田块与田埂的结构连通性，以提升水稻害虫天敌的种群数量。未来研究应聚焦于稻田的时空调控，以最大化生物防治的效果。
2018年6月12日