农业景观中环境因素对两栖类生物分布的影响

以黄河下游地区封丘县为研究区,在地理信息系统和R软件的支持下,在栖息地水平和景观水平上,分析了两栖类生物分布与栖息地变量(池塘水体溶解氧DO、电导率COND、浊度TURB、水体氨氮NH₃-N、池塘内植被盖度VEG_interior、池塘内挺水植物盖度EMER、池塘边缘植被盖度VEG_edge、两栖类幼虫捕食者PRE和池塘面积AREA)和采样点池塘250、500、1000、2000 m半径缓冲区内景观变量(池塘面积AP、与最近道路的距离DR、耕地面积AF、林地面积AW、Shannon多样性指数SHDI和蔓延度指数CONTAG)的关系.结果表明: 中华大蟾蜍的分布主要与栖息地变量中的PRE和较大缓冲区半径内的景观变量(AW2000、DR2000、SHDI1000、CONTAG1000)相关;黑斑侧褶蛙的分布与栖息地变量中的EMER和较小缓冲区半径内的景观变量(SHDI500)关系密切;金线侧褶蛙的分布主要与栖息地变量中的VEG_interior和PRE相关;泽陆蛙的分布主要与较大缓冲区半径内的景观变量(AF2000、SHDI2000)相关;两栖类生物总体上主要与栖息地变量中的EMER和较小缓冲区半径内的景观变量(SHDI500)相关.在农业景观中,保护两栖类生物应该保护永久性和半永久性池塘、提高池塘内部植被盖度、增强栖息地池塘之间的功能连通性.

Effects of environmental factors on the distribution of amphibians in agricultural landscape

We analyzed the relationship between the distribution of amphibians and the environmental variables at the habitat level and landscape level in Fengqiu County of Henan Province, a typical region of the lower reaches of the Yellow River, with the support of geographic information system (GIS) and R software. At the habitat level, dissolved oxygen (DO), conductivity (COND), turbidity (TURB), NH₃-N, pond-interior vegetation cover (VEG_interior), emergent vegetation cover (EMER), pond-edge vegetation cover (VEG_edge), benthic fauna predators (PRE), and pond area (AREA) were selected as habitat variables. At the landscape level, total area of ponds (AP), distance to the nearest road (DR), total area of farmlands (AF), total area of woodlands (AW), Shannon’s diversity index (SHDI), and contagion index (CONTAG) were selected as explanatory variables, calculated within a buffer of 250, 500, 1000 and 2000 m around the centroid of each pond. The results showed that the distribution of Bufo gargarizans was mainly related to the PRE and landscape variables within the larger radius buffer zone (AW2000, DR2000, SHDI1000, CONTAG1000). The distribution of Pelophylax nigromaculata was closely related to the EMER and landscape variables within the smaller radius buffer zone (SHDI500). VEG_interior and PRE were the key factors determining the distribution of Pelophylax plancyi. Landscape variables (AF2000, SHDI2000) within the larger buffer radius were the most significant influencing factors on Fejervarya multistriata. For all amphibian species, the EMER and SHDI500 were variables that should be considered. For the protection of amphibian species in plain agricultural landscape, we suggested that conservation efforts should focus on improving the pond-interior vegetation cover, protecting the semi-permanent ponds, and enhancing the functional connectivity among ponds.