Organic farming enhances parasitoid diversity at the local and landscape scale

1. The magnitude of the benefits derived from organic farming within contrasting managed landscapes remains unclear and, in particular, the potential scale-dependent response of insect parasitoids is relatively unexplored. Identifying the scale at which parasitoids are affected by organic farming will be an important step to enhance their conservation. 2. We sampled tachinid parasitoids at the centre and margin of arable and grassland fields on paired organic and conventional farms located in landscapes with different proportions of organic land. A total of 192 fields were sampled in two biogeographical regions of the UK. 3. We found that the positive effect of organic farming on tachinid parasitoid diversity can be observed at multiple spatial scales. At the local scale, we found higher abundance and species richness of tachinid parasitoids on organic than on conventional farms and on field margins than on field centres. At the landscape scale, the diversity of tachinids was higher in ...1. 在不同经营管理模式的景观中，有机农业所带来的生态效益量级仍不明确；其中，昆虫寄生性天敌的潜在尺度依赖响应更是鲜有研究。明确有机农业影响寄生性天敌的空间尺度，将是提升其保护成效的关键一步。 2. 本研究针对有机农田占比各不相同的景观中的配对有机与常规农田，在其耕地与草地田块的中心及边缘采集寄蝇科寄生性天敌（tachinid parasitoids）样本；最终在英国两个生物地理区域内，共完成192块农田的采样。 3. 研究发现，有机农业对寄蝇科寄生性天敌多样性的积极影响可在多个空间尺度上显现。在局部尺度下，有机农田的寄蝇科寄生性天敌个体丰度与物种丰富度均高于常规农田，且田块边缘的天敌丰度和物种丰富度也高于田块中心；在景观尺度下，寄蝇科天敌的多样性在……