INRAE Biostatistique et Processus Spatiaux, INRA-PACA, Avignon, France.
Institute of Horticultural Production Systems, Leibniz University Hannover, Hannover, Germany.
PLoS Comput Biol. 2021 Nov 8;17(11):e1009559. doi: 10.1371/journal.pcbi.1009559. eCollection 2021 Nov.
In agricultural landscapes, the amount and organization of crops and semi-natural habitats (SNH) have the potential to promote a bundle of ecosystem services due to their influence on ecological community at multiple spatio-temporal scales. SNH are relatively undisturbed and are often source of complementary resources and refuges, therefore supporting more diverse and abundant natural pest enemies. However, the nexus of SNH proportion and organization with pest suppression is not trivial. It is thus crucial to understand how the behavior of pest and natural enemy species, the underlying landscape structure, and their interaction, may influence conservation biological control (CBC). Here, we develop a generative stochastic landscape model to simulate realistic agricultural landscape compositions and configurations of fields and linear elements. Generated landscapes are used as spatial support over which we simulate a spatially explicit predator-prey dynamic model. We find that increased SNH presence boosts predator populations by sustaining high predator density that regulates and keeps pest density below the pesticide application threshold. However, predator presence over all the landscape helps to stabilize the pest population by keeping it under this threshold, which tends to increase pest density at the landscape scale. In addition, the joint effect of SNH presence and predator dispersal ability among hedge and field interface results in a stronger pest regulation, which also limits pest growth. Considering properties of both fields and linear elements, such as local structure and geometric features, provides deeper insights for pest regulation; for example, hedge presence at crop field boundaries clearly strengthens CBC. Our results highlight that the integration of species behaviors and traits with landscape structure at multiple scales is necessary to provide useful insights for CBC.
在农业景观中，由于作物和半自然生境（SNH）的数量和组织对生态群落在多个时空尺度上的影响，它们有可能促进一系列生态系统服务。SNH 相对未受干扰，通常是补充资源和避难所的来源，因此支持更多样化和丰富的自然害虫天敌。然而，SNH 比例和组织与害虫抑制的关系并非微不足道。因此，了解害虫和天敌物种的行为、潜在的景观结构及其相互作用如何影响保护生物防治（CBC）至关重要。在这里，我们开发了一个生成随机景观模型来模拟现实农业景观中农田和线性要素的组成和配置。生成的景观作为空间支撑，我们在其上模拟空间显式的捕食者-猎物动态模型。我们发现，增加 SNH 的存在通过维持高捕食者密度来促进捕食者种群，从而调节并将害虫密度保持在农药施用阈值以下。然而，捕食者在整个景观中的存在有助于通过将其保持在该阈值以下来稳定害虫种群，这往往会增加景观尺度上的害虫密度。此外，SNH 的存在与 Hedge 和 Field 接口之间的捕食者扩散能力的共同作用导致更强的害虫调节，这也限制了害虫的生长。考虑到田地和线性要素的特性，如局部结构和几何特征，为害虫调节提供了更深入的见解；例如，作物田边界上存在树篱明显加强了 CBC。我们的结果强调，将物种行为和特征与多尺度的景观结构相结合是提供有用的 CBC 见解的必要条件。
