Traditional gap analysis has been traditionally used to assess of the performance protected areas network in protecting amphibians and reptiles across the whole of Europe. Results varie greatly across the different thresholds used for assigning reserves to grid cells and the "arbitrary" criteria used to consider species as "protected". Thus,some researchers have highlighted the need to assess sensitivity of reserve effectiveness assessments to data and decision-rules. In the present paper researchers propose a new method to assess the effectiveness of protected areas,  avoiding these arbitrary decision rules. In this approach, they used null models to identify those species over and under-represented in protected area networks.

Reference Article:  Sánchez-Fernández, D., Abellán P. 2015. Using null models to identify under-represented species in protected areas: A case study using European amphibians and reptiles. Biological Conservation http: //dx.doi.org/10.1016/j.biocon.2015.02.006