Habitat Selection Of Amphibians In Agricultural Landscape

Amphibians are important for the health and stability of agro-ecosystems.Amphibians need to lay eggs in the water and spend their childhood,and over-age the adulthood in the terrestrial environment.The reproduction,survival,spread and migration of individuals require both aquatic and terrestrial ecosystems,so amphibians are very sensitive to their surroundings.The rapid fragmentation of cities,intensive agricultural production,and fragmentation and fragmentation of habitats caused by rural environmental damage are the main causes of the rapid decline in the number of amphibians.The plaques of different sizes scattered in the agricultural landscape are important "habitat islands" of amphibians.They understand the habitat utilization characteristics of amphibians in agricultural landscapes,especially the identification and selection of heterogeneous habitats by amphibians.The protection of amphibious biodiversity in agro-ecosystems is of great significance.In this study,the typical agricultural area in the lower reaches of the Huaihe River was used as the research area.Combined with the characteristics of the agricultural landscape in the area,35 ponds were selected as sampling points,and various methods such as visual observation,sound recording and dip net were combined.The amphibians in the area were surveyed,and the Shannon-Wienner index,Simpson diversity index,Pielou evenness index and Margalef richness index were used to analyze the species diversity.At the habitat level,the characteristics of 13 pond habitats such as pond water quality,vegetation coverage,pond slope and water depth were investigated.At the landscape level,according to the diffusion capacity of amphibians,the sampling buffers were within different buffer radius.The characteristics of landscape heterogeneity were analyzed(100m,250 m,500m,1000 m,1500m,2000m).Then,using redundancy(RDA)and statistical models,the key habitat factors affecting the distribution of amphibian are analyzed,and then the selection pattern of amphibians in habitats in agricultural landscape is determined.Research indicates:(1)The main species in the study area are: Pelophylax nigromaculata,Pelophylax planci,Bufo gargarizans,Fejervarya multistriata,Microhyla fissipes,Hyla chinensis,and Kaloula borealis.The dominant populations are the Pelophylax nigromaculata,Pelophylax planci,Fejervarya multistriata,.The pond occupancy rate is: Pelophylax nigromaculata > Pelophylax planci > Fejervarya multistriata > Bufo gargarizans > Microhyla fissipes > Hyla chinensis > Kaloula borealis.(2)The niche breadth characteristics of amphibians are as follows: Pelophylax nigromaculata > Fejervarya multistriata > Pelophylax planci > Bufo gargarizans > Microhyla fissipes.The dominant features of the Pelophylax nigromaculata and the Pelophylax nigromaculata are obvious,with high pond occupancy,high niche breadth,and high uniformity of pond distribution.In comparison,the density of Pelophylax planci is high.However,the distribution is uneven,and the niche breadth is also the lowest among the three dominant species in the study area.(3)RDA analysis showed that there was a significant positive correlation between the Pelophylax nigromaculata and the pH value and water temperature(r=0.373 ?p<0.05;r=0.340 ? p<0.05).The Pelophylax planci was significantly positively correlated with the vegetation coverage in the pond and the vegetation coverage outside the pond was significantly negative.Correlation(r=0.355?p<0.05;r=-0.335?p<0.05),ammonia nitrogen and total phosphorus in ponds are also important environmental factors affecting the Pelophylax planci;the Bufo gargarizans has a significant negative correlation with pH(r=-0.355?p<0.01),and the turbidity in water There is also a distribution of the Bufo gargarizans in the pond with higher conductivity;the Fejervarya multistriata has a significant positive correlation with the vegetation coverage and the vegetation coverage at the edge of the pond(r=0.426?p<0.01;r=0.411?p<0.05);It is the main influencing factor of the Microhyla fissipes(r=0.432?p<0.01).In addition,the depth of the pond and the vegetation coverage in the pond are also the main environmental factors affecting the habitat selection of the Microhyla fissipes.At the landscape level,within the small buffer radius(100m,250 m,500m),the pond area,quantity,density,distance from the road,distance from the building,the number of cultivated plaques,and the proportion of cultivated land are preferred.Variables;within the larger buffer radius(1000m-2000m),the total number of patches and the aroma diversity index,the fragrance uniformity index,and the spread index representing the landscape configuration characteristics are the main priority variables.(4)The simulation results of amphibians distribution and environmental factors show that the optimal habitat of the Microhyla fissipes is within 500 m.Compared with the heterogeneity of landscape composition,improving the heterogeneity of the landscape configuration is beneficial to species protection.The loyalty species of the frog habitat,the vegetation coverage of the pond in the small scale is the main habitat requirement of the Pelophylax planci;the optimal scale model of the Chinese cockroach appears at 500 m,and prefers to adapt to relatively dry and wide The habitat indicates that the habitat with high heterogeneity of landscape composition is more conducive to the survival of the Bufo gargarizans;the Fejervarya multistriata prefers the farmland habitat;for the overall abundance of amphibians,500 m is the best scale for model prediction.Therefore,the protection of amphibians should take measures from a multi-scale perspective to reduce human disturbance.Maintaining a certain proportion of non-agricultural plant coverage on the basis of ensuring the basic farmland production area is of great significance for the protection of amphibians.