Detecting nestedness in city parks for urban biodiversity conservation

Abstract

AbstractUrbanization has been a global phenomenon producing great environmental and ecological challenges including species composition shifts in urban areas. To evaluate the interaction networks of the inhabitant metacommunities in urban parks, we applied the nestedness analysis using ecological survey data of birds, reptiles, frogs, and butterflies among 16 parks in Taipei City of Taiwan and identified critical environmental factors for biodiversity conservation. Results found significant nestedness of the metacommunities among these parks, which indicated strong interaction networks and the importance of urban parks for sustaining these metacommunities. In addition, various types of land use had different effects on the species incidence of birds, reptiles, frogs, and butterflies. It demonstrates that landscape design should consider the taxonomic differences in the development of conservation guidelines. Results also showed that the area of parks and the area of woodlot in the park were critical elements for the nested structure. Nonetheless, abundant bird generalists were found to be highly related to the area of buildings within parks, distance to forests, rivers, and the neighbouring parks. Moreover, exotic species were found to affect the interaction networks of native species. However, based on the current information, we cannot confirm the actual effects of the exotic species on the native assemblages. Reptiles and frogs appeared to be more easily threatened by land development and habitat fragmentation due to their lower vagility. In this regard, we suggest that conservation action should focus on preserving green space with large areas and constructing green corridors, creating crucial elements, and increasing the vertical complexity in the parks for species with various vagilities. We believe these strategies can help reduce the impact of urbanization to retain healthy interactions and connections of metacommunities among habitats for effective biodiversity conservation in urban areas.