Data from: Landscape heterogeneity filters functional traits of rice arthropods in tropical agroecosystems

Biological control services of agroecosystems depend on the functional diversity of species traits. However, the relationship between arthropod traits and landscape heterogeneity is still poorly understood, especially in tropical rice agroecosystems which harbour a high diversity of often specialized species. We investigated how landscape heterogeneity, measured by three metrics of landscape composition and configuration, influenced body size, functional group composition, dispersal ability and vertical distribution of rice-arthropods in the Philippines. We found that landscape composition and configuration acted to filter arthropod traits in tropical rice agroecosystems. Landscape diversity and rice habitat fragmentation were the two main gradients influencing rice-arthropod traits, indicating that different rice-arthropods have distinct habitat requirements. Whereas small parasitoids and species mostly present in the rice-canopy were favoured in landscapes with high compositional heterogeneity, predators and medium-sized species occupying the base of the rice plant, including planthoppers, mostly occurred in highly fragmented rice habitats. We demonstrate the importance of landscape heterogeneity as an ecological filter for rice-arthropods, identifying how the different components of landscape heterogeneity selected for or against specific functional traits. However, the contrasting effects of landscape parameters on different groups of natural enemies indicate that not all beneficial rice-arthropods can be promoted at the same time when using a single land management strategy. Increasing compositional heterogeneity in rice landscapes can promote parasitoids but may also negatively affect predators. Future research should focus on identifying trade-offs between fragmented rice habitats and structurally diverse landscapes to maximize the presence of multiple groups of beneficial arthropods.

农业生态系统（agroecosystems）的生物防治服务（biological control services）有赖于物种性状（species traits）的功能多样性（functional diversity）。然而，节肢动物（arthropod）性状与景观异质性（landscape heterogeneity）之间的关联仍有待深入阐明，尤其是在物种丰富度极高且多为特化物种的热带水稻农业生态系统中。本研究以菲律宾的水稻节肢动物（rice-arthropods）为研究对象，采用景观组成（landscape composition）与景观配置（landscape configuration）的三类指标对景观异质性进行量化，探究其对水稻节肢动物体型大小（body size）、功能群组成（functional group composition）、扩散能力（dispersal ability）及垂直分布（vertical distribution）的影响。研究结果显示，景观组成与配置对热带水稻农业生态系统中的节肢动物性状起到了生态过滤作用。景观多样性与水稻生境破碎化是影响水稻节肢动物性状的两大核心环境梯度，这表明不同水稻节肢动物具有截然不同的生境需求。在组成异质性较高的景观中，体型偏小的寄生性天敌（parasitoids）以及主要栖息于水稻冠层（rice-canopy）的物种更具竞争优势；而占据水稻基部生境的捕食性天敌（predators）与中等体型物种（包括稻飞虱（planthoppers））则多集中于高度破碎化的水稻生境中。本研究证实了景观异质性作为水稻节肢动物生态过滤（ecological filter）因子的重要性，阐明了景观异质性的不同组分如何对特定功能性状产生定向选择或排斥作用。不过，景观参数对不同类群天敌（natural enemies）的影响存在显著差异，这意味着单一土地管理策略（land management strategy）无法同时促进所有有益水稻节肢动物的种群繁盛。提升水稻景观的组成异质性可助力寄生性天敌的繁衍，但同时可能对捕食性天敌产生负面影响。未来研究应聚焦于厘清破碎化水稻生境与结构多样化景观之间的权衡取舍（trade-offs），以最大化多类群有益节肢动物的种群留存。