Department of Entomology, The Ohio State University, 2021 Coffey Road, Columbus, Ohio, 43210, USA.
Department of Entomology, University of Kentucky, S123 Ag Science, North Lexington, Kentucky, 40546, USA.
Ecol Appl. 2021 Apr;31(3):e02282. doi: 10.1002/eap.2282. Epub 2021 Feb 5.
Urbanization is a key contributor to biodiversity loss, but evidence is mounting that cities can support rich arthropod communities, including rare and threatened species. Furthermore, greenspace is growing within hundreds of "shrinking cities" that have lost population resulting in a need to demolish an overabundance of infrastructure creating vacant land. Efforts are underway to transform vacant lots, often viewed as blighted areas, into habitats that promote biodiversity and generate ecosystem services, such as urban agroecosystems. To understand how reconfiguring these greenspaces might influence species conservation, elucidation of the factors that drive the distribution of an urban species pool is needed. In particular, the importance of species interactions in structuring urban communities is poorly understood. We tested hypotheses that (1) greater breadth of prey captured by web-building spiders and reduced overlap of prey capture among individuals facilitates the conservation of genera richness and abundance and (2) heterogeneity within a greenspace patch facilitates enhanced dietary niche breadth and greater resource partitioning. In 2013 and 2014, the abundance, breadth and degree of overlap in prey capture of sheet web spiders (Linyphiidae) was measured using web mimic traps at 160 microsites (0.25 m ) situated in four urban vacant lots and four urban farms in the city of Cleveland, Ohio, USA. Within a subset of 40 microsites, we used vacuum sampling and hand collection to measure the abundance and genera richness of Linyphiidae. Spider richness and abundance were significantly reduced within urban farms relative to vacant lots. The distribution of spiders and prey was explained by habitat structure, with microsites dominated by tall grasses and flowering plants, with a high bloom abundance and richness, supporting greater prey capture and a higher genera richness and abundance of spiders. In 2014, web capture overlap was significantly greater within microsites dominated by bare ground. These findings illustrate that urban greenspace conservation efforts that focus on reducing bare ground and incorporating a diversity of grasses and flowering plant species can promote linyphiid spiders, potentially by relaxing exploitative competition for shared prey.
城市化是生物多样性丧失的一个主要原因，但越来越多的证据表明，城市可以支持丰富的节肢动物群落，包括稀有和受威胁的物种。此外，在数百个人口减少的“收缩城市”中，绿地面积正在增加，这些城市由于需要拆除过多的基础设施而导致大量空地。人们正在努力将空地（通常被视为荒芜地区）改造成促进生物多样性和产生生态系统服务的栖息地，例如城市农业生态系统。为了了解重新配置这些绿地如何影响物种保护，需要阐明驱动城市物种库分布的因素。特别是，物种相互作用在构建城市群落中的重要性还了解甚少。我们检验了以下假设：（1）织网蜘蛛捕获的猎物种类越广，个体之间猎物捕获的重叠度越低，有利于维持属丰富度和丰度；（2）绿地斑块内的异质性有利于增强饮食生态位的广度和更大的资源分割。2013 年和 2014 年，在美国俄亥俄州克利夫兰市的四个城市空地和四个城市农场中，使用网模拟陷阱在 160 个微生境（0.25 米）上测量了片网蜘蛛（Linyphiidae）的丰度、广度和猎物捕获的重叠度。在 40 个微生境的一个子集中，我们使用真空采样和手动收集来测量 Linyphiidae 的丰度和属丰富度。与空地相比，城市农场中蜘蛛的丰富度和丰度明显降低。蜘蛛和猎物的分布由栖息地结构解释，微生境以高大的草和开花植物为主，具有高的开花量和丰富度，支持更多的猎物捕获以及更高的蜘蛛属丰富度和丰度。2014 年，在以裸地为主的微生境中，网捕获的重叠度显著增加。这些发现表明，城市绿地保护努力侧重于减少裸地，并纳入更多种类的草和开花植物，通过缓解对共享猎物的掠夺性竞争，可能会促进 Linyphiidae 蜘蛛的生存。
