Construction and optimization of ecological security pattern in karst basin considering lithology and geological disasters

Ecological security provides the basis of maintaining both a sustainable regional ecosystem and economic development. However, few studies have focused on how the features such as topography and geomorphology, lithologic stratigraphic assemblages, and geohazard distribution affect the construction of ecological security patterns and the layout of optimization measures. In order to comprehensively reveal the key areas and key objects of ecological restoration in karst basins, this study takes the Beipan River Basin (BRB) as an example, constructs an ecological security pattern (ESP) based on the methods of morphological spatial pattern analysis (MSPA), landscape connectivity analysis and circuit theory, and lays out the optimization measures in combination with the spatial distribution characteristics of topographic and geomorphological differences and lithological stratigraphic combinations. The results show that 151 ecological sources, 343 ecological corridors, 121 pinch points and 178 barriers constitute the ESP of the BRB. Lithology is closely related to the spatial distribution characteristics of ecological source sites. Level 1 and 2 ecological sources (The ecological sources were categorized into level 1, level 2, and level 3 source from high to low importance.) are concentrated in the Emeishan basalt region of the upstream and the clastic and impure carbonate rock region of the downstream part of the BRB; level 3 ecological sources are concentrated in the carbonate rock region of the midstream. Taking into account the outstanding ecological problems in the basin, and based on the characteristics of lithology and geohazard distribution, we propose the optimization scheme of "three axes, three zones and multiple points" for the ESP and the layout of specific measures of the BRB. The results can provide scientific references for maintaining ecological security maintenance in karst ecologically fragile areas.