Major factors affecting the distribution of Anuran communities in the Urban, Suburban and Rural areas of Shanghai, China

There is a dearth of information on the effects of landscape and microhabitat variables on the distribution of anurans in areas of rapid urban development, in both tropical and subtropical regions. Therefore, we studied 24 wetlands sites from the center of Shanghai city, China extending outward to rural areas. Sampling was performed from May through July 2014. Urbanization was categorized by the proportion of hard ground cover. Transect sampling and ‘calling’ surveys were used to investigated the richness and density of anurans; microhabitat factors were recorded simultaneously. One-way analysis of variance and Kruskal–Wallis tests were conducted to analyze differences of total density, species richness and density of individual anuran species in the three urbanization levels; redundancy analysis was carried out on the relationship between anuran density and environmental variables. Species richness was lowest in the areas where the proportion of hard ground cover was > 80%, and the total density of anurans was highest in the areas where coverage of the hard ground cover was < 30%. We recorded five species belonging to four genera and four families and an individual anuran species that had varied representations in urban environments. Beijing gold-striped pond frogs (Pelophylax plancyi) and Zhoushan toads (Bufo gargarizans) appeared to be well adapted to the Shanghai metropolis. Large water environments and aquatic vegetation (floating-leaves and emergent vegetation) were indicators of the presence of Beijing gold-striped pond frogs. The density of black-spotted pond frog (Pelophylax nigromaculatus) was at the lowest density in the areas where hard ground coverage was > 80%, and tended to prefer larger bodies of water. Hong Kong rice-paddy frogs (Fejervarya multistriata) and ornamented pygmy frogs (Microhyla achatina) both suffered severely from cropland loss due to urban development. Bare land around breeding grounds was important for Hong Kong rice-paddy frogs, since it usually chooses mud coast caves for hibernation.