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

Abstract

SelectingFengqiu 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 information 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 dispersal 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.