Green roofs offer numerous environmental benefits, and thus their implementation is considered an initiative to create sustainable cities. However, the characteristics of green roofs that could enhance arthropod biodiversity and ecological functioning are poorly known, especially for South American countries. Here, we analyzed the influence of several characteristics of green roofs (plant species richness, vegetation cover of the roof, age, substrate depth, area, and isolation in terms of height and green cover in the landscape scale) on the abundance, richness (total and by functional feeding groups), and community composition of arthropods. To do that, we selected 30 green roofs located in different urbanization contexts, from small towns in semi-rural areas to Cordoba, the second-largest city of Argentina. Our results indicated a high diversity of arthropods, registering a total of 12,942 individuals corresponding to 505 species from 14 orders, being herbivores and parasitoids the dominant groups. The area of the green roofs was positively linked to total species richness, species richness of most functional feeding groups, and total abundance of arthropods. The community composition of arthropods on green roofs was also affected by their area, and by the green cover in the landscape. Moreover, green roofs with higher plant richness, mainly spontaneous, and less isolated (both vertically and horizontally) favored entomophagous arthropods. Other variables, such as age and vegetation cover of the green roofs, were also important for herbivores, predators, parasitoids and detritivores. Our study clearly demonstrates that green roof size is not all that matters for supporting arthropod biodiversity because promoting high plant diversity, allowing spontaneous ecosystem dynamics, and diminishing roof isolation foster entomophagous arthropod diversity. Our study is the first that considers multiple factors of roofs in South America and provides key knowledge for stakeholders interested in the development and management of this green infrastructure in semi-rural and urban landscapes.

绿色屋顶可带来许多环境效益，因此，实施绿色屋顶被认为是创建可持续城市的一项举措。然而，鲜为人知的绿色屋顶可以增强节肢动物的生物多样性和生态功能，但对南美国家却知之甚少。在这里，我们分析了绿色屋顶的几个特征（植物物种丰富度，屋顶的植被覆盖率，年龄，基质深度，面积以及景观高度和绿色覆盖物的隔离度）对丰度，丰富度的影响（总数和功能性进食组），以及节肢动物的群落组成。为此，我们选择了30种位于不同城市化环境中的绿色屋顶，从半农村地区的小镇到阿根廷第二大城市科尔多瓦。我们的结果表明节肢动物的多样性很高，总共登记了12942个个体，对应于14个目中的505个物种，其中草食动物和寄生类动物占主导地位。绿色屋顶的面积与总物种丰富度，大多数功能性摄食组的物种丰富度以及节肢动物总丰富度呈正相关。绿色屋顶上的节肢动物的社区组成也受到其面积以及景观中绿色覆盖物的影响。此外，具有较高植物丰富度的绿色屋顶（主要是自发的）和较少的隔离（垂直和水平方向）更有利于食虫节肢动物。其他变量，例如年龄和绿色屋顶的植被覆盖度，对草食动物，捕食者，拟寄生物和有害生物也很重要。我们的研究清楚地表明，屋顶绿化的规模并不是支持节肢动物生物多样性的全部因素，因为促进高植物多样性，允许自发的生态系统动态变化和减少屋顶隔离会促进食虫性节肢动物的多样性。我们的研究是第一个考虑南美屋顶因素的研究，为有兴趣在半农村和城市景观中开发和管理这种绿色基础设施的利益相关者提供了关键知识。