The causes and consequences of pest population variability in agricultural landscapes

Variability in population densities is key to the ecology of natural systems but also has great implications for agriculture. Farmers’ decisions are heavily influenced by their risk-aversion to pest outbreaks that result in major yield losses. However, the need for long-term pest population data across many farms has prevented researchers from exploring the drivers and implications of pest population variability. Here, we demonstrate the critical importance of population variability for sustainable farming by analyzing 13-yrs of pest densities across >1300 Spanish olive orchards and vineyards. Variable populations were more likely to cause major yield losses, but also occasionally created temporal windows when densities fell below insecticide spray thresholds. Importantly, environmental factors regulating pest variability were very distinct from factors regulating mean density, suggesting variability needs to be uniquely managed. Finally, we found diversifying landscapes may be a win...

种群密度的变异性是自然系统生态学的核心议题，同时对农业生产亦具有重要意义。农户的决策在很大程度上受其对害虫暴发引发重大产量损失的风险厌恶心理影响。然而，跨多农场获取长期害虫种群数据的需求，阻碍了研究者探索害虫种群变异性的驱动因素与影响。本研究通过分析西班牙1300余处橄榄园与葡萄园的13年害虫密度数据，阐明了种群变异性对可持续农业的关键重要性。种群密度波动较大的情况更易引发重大产量损失，但偶尔也会形成害虫密度低于杀虫剂喷施阈值的时间窗口。尤为重要的是，调控害虫种群变异性的环境因素，与调控种群平均密度的环境因素存在显著差异，这表明需针对种群变异性采取差异化管理策略。最后，本研究发现景观异质性或许是一项双赢的……