Data from: Plant damage in urban agroecosystems varies with local and landscape factors

Biotic and abiotic factors at local to landscape scales influence insect pest and disease dynamics in agricultural systems. However, relative to studies focused on the importance of these drivers of crop plant damage in rural agricultural systems, few studies investigate plant damage from herbivore insects and plant diseases in urban agroecosystems, and consequently, most urban farmers lack knowledge on crop protection tactics. Here we use three common crop species within urban agroecosystems (community gardens) distributed across an urban landscape as a model system to ask how local, landscape, and microclimate factors relate to herbivore and disease plant damage. We hypothesized that plant damage would be lower in gardens with greater local vegetation complexity, landscape-scale complexity, and less variable temperatures, but that the importance of factors is species- and damage-specific. By measuring <i>Brassica</i>, cucurbit, and tomato insect pest and disease damage across the growing season, we confirmed that the importance of factors varies with crop species and by damage type. Both local complexity factors (e.g., number of trees and shrubs) and landscape complexity (percent natural cover in the landscape) relate to lower incidence of herbivore and disease damage on some crops, supporting our prediction that habitat heterogeneity at both local and landscape scales lowers plant damage. Greater temperature variability related to higher disease damage on tomatoes linking microclimate factors to disease prevalence. Yet, local complexity factors also related to higher incidence of plant damage for other crop species, indicating variable species-level impacts of local management factors on plant damage. By measuring the abundance of fungus-feeding lady beetles (<i>Psyllobora</i>) on cucurbits, we confirmed a strong association between natural enemies and powdery mildew. We provide a case study on how changes in local to landscape-scale factors relate to plant damage in urban agroecosystems and suggest how urban farmers and gardeners can apply this ecological knowledge to improve sustainable urban food production.

从局地到景观尺度的生物与非生物因子，会影响农业生态系统中的昆虫害虫与病害动态。然而，相较于针对乡村农业系统中作物受害驱动因子重要性的相关研究，目前针对城市农业生态系统（urban agroecosystems）中植食性昆虫与植物病害导致作物受害的研究仍较为匮乏，因此多数城市农户缺乏作物保护相关的专业知识。本研究以分布于城市景观中的城市农业生态系统内的3种常见作物为研究对象，选取社区菜园（community gardens）作为模式系统，探究局地、景观及微气候因子与植食性害虫和病害导致的作物受害之间的关联。我们提出如下假说：局地植被复杂度、景观尺度复杂度更高且温度变异性更低的菜园，作物受害程度会更低；且各驱动因子的重要性会因作物种类和受害类型而异。通过在整个生长季内监测芸苔属（*Brassica*）、葫芦科作物（cucurbit）及番茄（tomato）的害虫与病害受害情况，本研究证实了驱动因子的重要性会随作物种类和受害类型发生变化。局地复杂度因子（如树木与灌木数量）和景观复杂度（景观内自然植被覆盖占比）均与部分作物的植食性害虫及病害受害率降低相关，验证了我们的预测：局地与景观尺度的生境异质性会降低作物受害程度。温度变异性更高则与番茄的病害受害程度加重相关，这将微气候因子与病害流行程度关联了起来。但局地复杂度因子也与部分其他作物的受害率升高相关，这表明局地管理因子对作物受害的影响会因作物种类而异。通过监测葫芦科作物上食菌瓢虫属（*Psyllobora*）的种群丰度，本研究证实了天敌与白粉病（powdery mildew）之间存在显著关联。本研究通过案例分析，阐明了从局地到景观尺度的因子变化如何影响城市农业生态系统中的作物受害情况，并为城市农户与菜园经营者如何应用该生态学知识以提升可持续城市粮食生产能力提供了可行建议。