The Influence Of Landscape Structure And Habitat Type On Amphibian In Different Urbanization Area Of Shanghai

The Earth is suffering global biodiversity loss,and amphibians have become the most vulnerable vertebrates,comparing with birds and mammals.As the important predators and preys in both terrestrial and aquatic ecosystems,amphibians promote substance circulation and energy flowing of the whole ecosystem.Unfortunately,urbanization claimed surprisingly 88% of the biodiversity drop and population reduction of amphibians in the world.Urbanization caused their habitat loss,habitat fragmentation,and habitat quality decline.China is experiencing an intensive urbanization and as a result,amphibian biodiversity is undergoing a grievous decline.However,limited studies has focused on amphibian distribution and habitat selection in human-dominant landscapes.Therefore,it is of great importance to understand amphibian biodiversity and habitat use pattern in the urban environment.It is essential for biodiversity conservation in urban ecosystems to understand the habitat use pattern of amphibians,especially the effects of species-area relationship and landscape heterogeneity on amphibian diversity.Parks have become “islands,” or habitat fragments,for amphibians in highly urbanized areas.Cropland,woodland and wetland(pond)were three main typical habitats for amphibians in rural Shanghai.The differences of habitats and amphibian ecological characteristics may cause diverse distributions of amphibians.However,scarce number of study focuses on the distribution of amphibian in rural Shanghai.Additionally,amphibians are also threatened by the intensification of agriculture throughout the world.Understanding how agricultural landscape structure and habitat types affect amphibian also contribute to amphibian biodiversity conservation.Body condition index is an indicator of animal physiological status and nutritional condition.Several studies have shown the negative effect of urbanization on amphibian population size,but few study has looked at the correlation between landscape change caused by urbanization and body condition index of amphibians.In this study,we chose Shanghai city as our study site,which has sustainably the highest urbanization rate in China.Investigations on amphibian distributions were performed in urban parks,rural agroforestry ecosystems of Shanghai in 2014-2016.We used several analysis tools to examine how landscape structure(especially landscape heterogeneity)and habitat type influence amphibian community composition and population health,including One-Way ANOVA,principal component analysis,multivariate regression analysis,and general linear mixed model.Our results showed that:(1)Visual encounter method was used to survey anuran communities(species richness and abundance)in 16 parks located in highly urbanized areas of Shanghai,China.Landscape heterogeneity was measured as landscape compositional heterogeneity(using landscape Shannon diversity index)and landscape configurational heterogeneity(using landscape edge density).Fragment size,fragment shape,breeding habitat diversity and human disturbance in urban parks were included as predictor variables.The edge density of different land use types were also measured to examined their effects on dominant anuran abundance in Shanghai’s urban parks.We found that breeding habitat diversity and landscape configurational heterogeneity had significant positive effects on anuran species richness and relative abundance,respectively,in the urban parks.We also found that high edge density along streams benefited anuran abundance.However,there was no significant relationship between fragment size and anuran communities,and the abundances of Pelophylax plancyi and P.nigromaculata were negatively associated with the edge density of large ponds and roads.Our results suggest the importance of landscape structure in urban parks for sustaining anuran persistence.In addition,breeding habitat diversity and landscape configurational heterogeneity should be considered positive indicators of anuran biodiversity conservation in fragmented urban habitats.(2)From May to August in 2014 and 2016 amphibian biodiversity census were conducted in 30 study sites of three typical habitats in rural Shanghai.One-Way ANOVA was used to compare the amphibian community structure across three habitats in rural Shanghai,hierarchical clustering method was undertaked to analyse the similarity of amphibian community structure in different habitat.The results showed a total of 5,397 anuran individuals were recorded in two years,which belonging to 1 order,4 families,4 genera and 5 species.The dominant species of amphibian in rural Shanghai were Fejervarya multistriata and Pelophylax plancyi.There were significant differences in the species richness of amphibian among the rural habitats,but we did not find any corresponding significant differences in abundance.F.multistriata and Microhyla fissipes have a significant higher population densities in cropland habitat.Pelophylax nigromaculata and P.plancyi have a significant higher population densities in pond habitat.We did not find significant difference in population densities of Bufo gargarizans among different habitats.The results of cluster method indicated that woodland and pond habitats were classified into the same group,however the cropland habitats were classified into anotherone.Our study suggest that habitat protection and restoration in rural Shanhai is one of the key issues to undertake the biodiversity conservation for amphibian.(3)In order to investigate the differences in the body condition of the rice frog(Fejervarya multistriata)in farmland irrigation ditches,fruit forest drainage ditches,and lotus ponds in agricultural landscapes to examine the effects of the agricultural landscape structure on the abundance and body condition of rice frogs.We conduct anuran census and sampled the body condition index for 225 individual rice frogs from 20 agricultural landscapes in Shanghai,China.Landscape variables comprising the compositional heterogeneity(using landscape Shannon diversity index),configurational heterogeneity(using landscape edge density),and area in rice farmland of 2-km buffer were measured in each landscape.The body condition index of rice frogs was lower in farmland irrigation ditches than other two habitats.In addition,configurational heterogeneity had a significant positive relationship with rice frog abundance,but a negative association with the body condition index for male rice frogs in the breeding season.Our results suggest that structuring diverse cropping patterns is essential for maintaining the body condition of rice frogs in the agricultural landscape in China.The influence of configurational heterogeneity caused by farm patterns in the agricultural landscape on anuran biodiversity should also be studied further because there were different effects of the edge density on rice frog population health.(4)In order to test whether the distribution and body condition of the rice frog(Fejervarya multistriata)and gold-striped pond frog(Pelophylax plancyi)are influenced by increasing urbanization in Shanghai,China.The census of F.multistriata and P.plancyi were done in Chongming、Qingpu、Songjiang and Houtan Park of 2014.Four study sites with six indicators of the major land-cover types were scored to indicate their position on an urbanization gradient.We sampled the body condition index for 212 individual rice frogs and 174 individual gold-striped pond frogs from 4 study sites in Shanghai,China.We found that both the density and body condition of F.multistriata declined significantly along this gradient.Although we observed a significant difference in body condition of P.plancyi among study sites with different degrees of urbanization,we did not find any corresponding significant differences in population density.