Data from: Scale dependencies and generalism in host use shape virus prevalence

Processes that generate the distribution of pathogens and their interactions with hosts are not insensitive to changes in spatial scale. Spatial scales and species traits are often selected intentionally, based on practical considerations, ignoring biases that the scale and type of observation may introduce. Specifically, these biases might change the interpretation of disease-diversity relationships that are reported as either ‘dilution’ or ‘amplification’ effects. Here, we combine field data of a host-pathogen community with empirical models to test the effects that i) spatial scale and ii) host range have on the relationship between plant-virus infection prevalence and diversity. We show that prevalence-diversity relationships are scale dependent, and can produce opposite effects associated with different habitats at sub-ecosystem scales. The total number of host species of each virus reflected generalism at the ecosystem scale. However, plasticity in host-range resembled habitat-specific specialisation and also changed model predictions. We show that habitat heterogeneity, ignored at larger (ecosystem) spatial scales, influences pathogen distributions. Hence, understanding disease distributions and the evolution of pathogens requires reconciling specific hypotheses of the study with an appropriate spatial scale, or scales, and consideration of traits, such as host range, that might strongly contribute to biotic interactions.调控病原体分布及其与宿主相互作用的生态过程，对空间尺度的变化并非无响应。研究中常基于实用考量人为选取空间尺度与物种性状，却忽视了观测尺度与观测类型可能引入的偏倚。具体而言，这类偏倚可能改变对疾病-多样性关系的解读——这类关系常被描述为‘稀释效应’或‘扩增效应’。本研究结合宿主-病原群落的野外调查数据与经验模型，检验了两个因素对植物病毒感染患病率与物种多样性之间关系的影响：一是空间尺度，二是宿主范围。研究结果表明，患病率-多样性关系具有尺度依赖性，在亚生态系统尺度下，不同生境会催生截然相反的效应。在生态系统尺度下，每种病毒的宿主物种总数体现了其宿主广谱性。然而，宿主范围的可塑性表现出生境特化的特征，同时也会改变模型的预测结果。研究还发现，在更大尺度（生态系统尺度）下被忽略的生境异质性，会对病原体的分布产生影响。因此，要理解疾病的分布规律与病原体的演化过程，需要将研究的特定假说与合适的（或多个）空间尺度相匹配，并考量宿主范围这类可能对生物相互作用产生显著影响的性状。