Researches On Ecological Status And Breeding Habitats Of The Anuran Community In Parks Of Shanghai

Urbanization growth leads to changes in habitat environment,which is a vital factor in the extinction of urban amphibious species.Therefore,how to create habitat microhabitat to protect existing urban amphibians is particularly important.Since the reform and opening up,a variety of amphibian species in Shanghai have extincted in the process of urbanization.But some native amphibian species do not seem to be"negatively affected"by urbanization,and are able to adapt and survive.As an"environmental indicator species",how did the tailless amphibian adapt and make use of its habitat micro-habitat to survive and reproduce under urbanization?Studying this issue can effectively link urban ecological construction and amphibian conservation.While improving the ecological functions of the existing urban parks in Shanghai,more than 20 country parks have been built or are under construction.The park has become an important place for urban amphibians to inhabit and reproduce.Amphibian conservation is not only an important goal of the ecological construction of the park,but also an important index to measure the effect of ecological environmental protection of the park.Therefore,in the construction of urban parks and country parks,it is of great significance to create micro-habitats suitable for the survival and reproduction of existing amphibians.Therefore we set up and studied the following three scientific questions:(1)what is the living condition of amphibians in urban parks and country parks in Shanghai?(2)what are the key micro-habitat variables influencing the distribution of amphibians in country and urban parks?(3)what is the optimal microenvironment index for each amphibian in different types of parks?We selected Shanghai,the typical urbanization city in China,as a research site,and conducted the investigations which included the distribution of amphibians and16 microenvironmental variables among the three environmental factors in the habitat of six country parks(104 transect lines)and six representative urban parks(40 transect lines).Our results showed that:5 different species(Fejervarya multistriat,Pelophylax plancyi,Pelophylax nigromaculatus,Microhyla fissipes,Bufo gargarizans)have been investigated in country parks and urban parks,with a total of 1821/times and country parks and urban parks both have the largest proportion of the distribution of P.plancyi.All the statistics were conducted by R 3.5.1.The ANOSIM similarity test results reveal that the species distribution(R=0.128,P=0.001)and habitat microenvironment(R=0.092,P=0.001)of country parks and urban parks are significantly different.Pearson correlation analysis shows that there is an autocorrelation between some environmental factors.Detrended Correspondence Analysis(DCA)indicated that the longest gradients of evaluating the distribution of anuran species were 2.559 and 2.324 in country and urban parks respectively.Therefore linear models were selected and Redundancy Analysis(RDA)were used to study how the 16 habitat variables would influence the distribution patterns of anuran species in the two kinds of parks.RDA analysis and Monte Carlo replacement test indicate that environmental variables had prominent effects on the distribution of amphibians in country parks(F=1.94,P=0.039)and urban parks(F=2.205,P=0.032).Four variables were found of significant influence to the distribution of anurans with their importance from high to low in the country park:the floating leaved vegetation coverage(FLV,r2=0.5437,P<0.001),distance to the nearest road(DR,r2=0.2242,P=0.003),WT(r2=0.2073,P=0.002),and BT(r2=0.1103,P=0.037).FLV(r~2=0.500,P=0.001)and WS(r~2=0.188,P=0.023)were the only two significant variables in the urban park.The PRDA analysis indicates that vegetation factors,water body factors and topographic factors have both separate and combined effects on the distribution of amphibians,vegetation factor is most important in country parks(?=26.50%)and urban parks(?=41.71%).The regression and decision tree quantifies the relationship between the abundance and significant effect factors of each type of anuran,providing an ecological identification indicator for species conservation.There are conclusions of this study based on these results:(1)The most critical environmental variables were the coverage of floating vegetation,which could be used as an ecological indicator to determine the distribution of amphibians.However,due to the difference in urban growth and management methods,the amphibians in country parks and urban parks also show differences in the response to the changes in some microenvironments.(2)The distance from habitats to roads has a significant effect on the distribution of amphibians in country parks,but not significant in the urban parks.(3)the main amphibians in the country parks notably prefer the waters on the natural slopes,while the urban parks show not marked effect.(4)he salinity of water significantly affects the distribution of amphibians in urban parks,but not in country parks.(5)According to the characteristics of different anuran species in different types of parks,we quantified the ecological indicators of the best habitat for each species,which provided a theoretical basis for park construction and anuran conservation.