Jarrett Crinan, Powell Luke L, Claire Tabe Tiku Regine, Kowo Cyril, Ferreira Diogo F, Quiñones Alma L S, Welch Andreanna J, Haydon Daniel T, Matthiopoulos Jason
Bird Migration Unit, Swiss Ornithological Institute, Luzern, Switzerland.
School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK.
Ecol Appl. 2025 Sep;35(6):e70093. doi: 10.1002/eap.70093.
High biodiversity and agricultural productivity are commonly regarded as mutually exclusive. However, functionally diverse communities may provide valuable services to agroecosystems and therefore offer the possibility of win-win strategies. We developed a dynamic mechanistic community model of the bird-arthropod food web associated with African cocoa agroforestry, structurally informed by metabarcoding data on bird diets, and fitted to trapping data on species abundances. Our novel framework models rates of change and uses space-for-time substitution, thus providing insights into community dynamics without the need for long time-series data. We used our fitted model to predict equilibrium community composition under varying intensities of shade management and pesticide use. Our results indicate that low-intensity farming favors forest bird species, with at least two times the biomass of this bird group compared to any other at high shade cover. Low-intensity farms also favored potential pollinator abundance, while biomass of the main pest species of cocoa, brown capsid, was 25% lower at high shade than at low shade. Our model quantified the net effect of each taxon on the other taxa in the food web: most bird to arthropod interactions were negative, indicating important pest control services provided by birds. Furthermore, our simulations of pesticide application revealed that the long-term effect of pesticide use on biomass of taxa varied according to shade cover. Importantly, pesticide application resulted in the decline of non-pest taxa through trophic cascades: forest birds were the taxa that declined the fastest, and this trend was exacerbated in low shade farms. To achieve a decline of less than 50% in non-pest taxa, pesticide application could only reach 10% in the sunniest farms and 20% in shady farms, which results in a maximal reduction of 19% in pest biomass. By looking at the efficacy of agricultural management through the lens of community interactions, our holistic, quantitative approach demonstrates that low-intensity agriculture may provide a win-win for biodiversity and ecosystem services.
高生物多样性和农业生产力通常被认为是相互排斥的。然而，功能多样的群落可能为农业生态系统提供有价值的服务，因此提供了双赢策略的可能性。我们开发了一个与非洲可可农林相关的鸟类 - 节肢动物食物网的动态机理群落模型，其结构由鸟类饮食的宏条形码数据提供信息，并与物种丰度的诱捕数据相拟合。我们新颖的框架对变化率进行建模，并使用空间换时间替代法，从而无需长期时间序列数据就能洞察群落动态。我们使用拟合模型预测在不同遮荫管理强度和农药使用情况下的平衡群落组成。我们的结果表明，低强度农业有利于森林鸟类物种，在高遮荫覆盖率下，该鸟类群体的生物量至少是其他任何群体的两倍。低强度农场也有利于潜在传粉者的丰度，而可可的主要害虫物种褐盲蝽的生物量在高遮荫下比低遮荫下低25%。我们的模型量化了食物网中每个分类群对其他分类群的净影响：大多数鸟类与节肢动物的相互作用是负面的，这表明鸟类提供了重要的害虫控制服务。此外，我们对农药施用的模拟表明，农药使用对分类群生物量的长期影响因遮荫覆盖率而异。重要的是，农药施用通过营养级联导致非害虫分类群数量下降：森林鸟类是下降最快的分类群，这种趋势在低遮荫农场中更为加剧。为了使非害虫分类群数量下降不到50%，在阳光最充足的农场中农药施用只能达到10%，在遮荫农场中为20%，这导致害虫生物量最大减少19%。通过从群落相互作用的角度审视农业管理的功效，我们的整体定量方法表明，低强度农业可能为生物多样性和生态系统服务带来双赢局面。
