An urban eco-environmental sensitive areas assessment method based on variable weights combination

When assessing urban eco-environmental sensitive areas (Urban Eco-ESAs) by multi-criteria evaluation method, the widely used weighted linear combination method may inevitably lead to some factors of high sensitive value being neutralized by other factors of low sensitive value, resulting in the neglect of some eco-sensitive areas as a consequence, while on the other hand, Boolean OR combination method, which give a result of high sensitive value as long as any factor has the value of high sensitivity and thus ignore the mutual compensation mechanism among ecological factors, can lead to excessively wide ranges of the eco-sensitive areas. To overcome the defects of these two methods, the authors propose an Urban Eco-ESAs synthesized assessment method giving finely controlled priority to bottleneck factors, and relative model based on selective local encouraging variable weights combination. The method is able to increase the weights of some eco-bottleneck factors on the basis of a weight-changing function in synthesizing multiple factor assessments as long as their assessment values break the bottleneck threshold values, which can guarantee the eco-sensitive areas identified by bottleneck factors being embodied in the final result, while also retain the compensation effect of multiple ecological factors, which makes the results of the assessment more reasonable. In order to deliver this empirical research, Taogang Town in China, which is adjacent to Net lake wetland nature reserve area, has been used as an example to confirm the validity of the method and the model.