The Nestedness of Metacommunities Among Parks in Urban Areas

Urbanization has been a common phenomenon globally that creates great environmental changes and causes species composition shifts in urban areas. To evaluate the role of parks and their surrounding configuration for sustaining the biodiversity, we applied the nestedness analysis to examine the interaction networks of the inhabitant communities of bird, reptile, frog, and butterfly among 16 parks in the Taipei city of Taiwan, followed by Spearmans correlation test to identify influence of the environmental factors on the nested structure. Results showed that all the four metacommunities appeared significant nested structure among the parks, yet the metacommunities of frog and reptile showed stronger nestedness than those of bird and butterfly. Results also found significant correlation among the metacommunities of bird and butterfly to area and boundary ratio of parks. Moreover, birds were highly related to the area of buildings within parks, distance to the nearest forests, water zone, and other parks, but these may be biased correlations because we did not partition the influence from the generalist bird species. Furthermore, results showed the importance of the area of trees and shrubs to birds and butterflies, but reptiles were only found to be correlated to the area of trees. In particular, results showed random effects of exotic species on the interaction networks of native species. In this regard, we suspect that the nested structure is associated with the mobility of a community, and biodiversity conservation should consider the interaction networks of native versus exotic species. Consequently, to help retain healthy interactions and connections among different metacommunities and the habitats, it is recommended to create crucial elements in the parks for various mobility level species, such as large and multi-layered trees, and green corridors between parks, as well as to focus on controlling the exotic species for biodiversity conservation in urban areas. Acknowledgment We sincerely thank the Ministry of Science and Technology, Taiwan (Grant No. MOST 108-2621-M-002-010-MY3) for the funding support to this study.