Integrative fuzzy set pair model for land ecological security assessment: a case study of Xiaolangdi Reservoir Region, China

Due to the increasingly serious ecological degradation of land systems, the land ecological security issues have attracted more and more attention of policy makers, researchers and citizens. Aiming at overcoming the disadvantages in subjectivity and complexity of the currently used assessment methods, an integrative fuzzy set pair model for assessing the land ecological security was developed by integrating fuzzy assessment and set pair analysis (SPA). The approximate degree of land ecological security to the optimal standard set was calculated to describe the secure level by combining multiple indices. The indices and weights were determined by a pressure-state-response model and the fuzzy analytic hierarchy process (AHP), respectively. Aided by a geographic information system, this model was applied to evaluate comprehensively the status of land ecological security in Xiaolangdi Reservoir Region, China, taking the administrative division as the assessment unit. The results showed that 20% of the total area maintained a slightly secure status, while 50% of the study area was of a middle or seriously low grade of land ecological security. The remaining portion (30%) was the most ecologically insecure. From the spatial prospective, obvious variations were observed. The land eco-security gradually decreased from the Xiaolangdi Dam to its surrounding regions. It was concluded that the status of the integral land ecological security of Xiaolangdi Reservoir Region was in the middle level, and increasingly intense human activities speeded up the degradation of regional land ecosystem in recent years and thus induced the crisis of land ecological security.