Ecological network construction of the heterogeneous agro-pastoral areas in the upper Yellow River basin

Abstract

The increasing landscape heterogeneity in the agro-pastoral areas and the contradiction between the development and biodiversity conservation is becoming more and more prominent, especially in Northwest China. Rational ecological network construction has become an important issue for ecological restoration and ecological security pattern strategy. Taking a typical agro-pastoral ecotone in the upper Yellow River valley as the study area, an ecological network was established using Graphab software based on the integral landscape heterogeneity analysis, in which the morphological spatial pattern analysis (MSPA) and structural equation model (SEM) were used to identify the ecological source regions and determine the resistance surface. The results showed that grazing and agricultural activities are the main reasons for the landscape complexity and heterogeneity. SEM also revealed the interactions between geographical conditions and landscape heterogeneity. The regression coefficients showed that the contribution of various factors on landscape heterogeneity were in order from strong to weak elevation, roads, settlements and slope. The influencing effects on landscape patterns were mainly reflected by the patch density, fractal dimension and landscape division indexes, with coefficients of −0.94, −0.91 and −0.88, respectively. The established ecological network shows that the overall planning of natural habitat and cultivated land will effectively improve the landscape quality. The presence of "stepping stone" patches in the central and eastern regions of the study area increases the landscape connectivity. In addition, the rational planning and utilization of high heterogeneity areas in the landscape are critical for maintaining the structure and function of the landscape. Findings from our study could provide a reference method for maintaining the landscape stability and sustainable development of heterogeneous agro-pastoral ecotones.