黄河下游平原农业景观异质性对两栖类生物栖息地可用性的影响

Effects of landscape heterogeneity on the availability of amphibians' habitats in agricultural region on the lower reaches of the Yellow River,China

以黄河下游典型平原农业景观封丘县为研究区,基于图论的分析方法,采用概率连通性指数(PC)和斑块重要值(dPC_k)表征池塘栖息地可用性程度,在地理信息系统和R软件的支持下,分析了两栖类物种在250、500、1000和2000 m不同扩散能力下,反映池塘栖息地组成和构型的池塘平均面积(MS)以及池塘数量(NP)、至道路的最近距离(DR)组合作用对池塘栖息地可用性的影响.结果表明:两栖类栖息地的可利用性与池塘数量、池塘平均面积和至道路的最近距离关系密切.在250 m扩散能力下,池塘平均面积和池塘数量是决定池塘可利用程度高低的重要影响因素;在500 m扩散能力下,池塘平均面积和至道路的最近距离对栖息地可用性的影响最为显著;在物种相对较高扩散能力下(1000和2000 m),池塘平均面积和池塘数量是最主要的影响因素.在平原农业景观中,两栖类生物及其栖息地的保护要充分考虑池塘斑块的数量、平均面积以及至道路的最近距离.

Selecting Fengqiu County in Henan Province, a typical region of the lower Yellow River, as the study area, adopting the analysis method of graph theory, with the support of geographic in- formation systems （GIS） and R software, we analyzed the effects of landscape composition and landscape configuration, the mean pond size （ MS）, the number of ponds （ NP ）, and distance to the nearest roads （DR） , on habitat availability of amphibian species under different levels of dis- persal ability （250, 500, 1000 and 2000 m）, by referring the probability index of connectivity （PC） and the important value of patches （percentage of the variation in PC, dPCk ） to the degree of availability of ponds for amphibians＇ breeding. The results indicated that the ponds availability for amphibians＇ breeding was closely related to MS, NP, and DR. Therein, MS and NP were the key factors determining the availability of ponds under the dispersal ability of 250 m, and then MS and DR were the most significant influencing factors on pond availability under the dispersal ability of 500 m. However, under the high dispersal ability （1000 and 2000 m）, MS and NP were the most important factors determining the availability of ponds. Therefore, with regard to the protection of amphibian species and their habitats in plain agricultural landscape, the number, mean size, and distances to the nearest roads of ponds should be taken into full consideration.