Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:…results in the light of the current debate concerning the probable agents responsible for the high level of biodiversity and its geographical distribution across the different biogeographical regions in this continent (Hoorn et al. 2010; Antonelli & Sanmartin 2011; Rull 2011; S ersic et al. 2011).
Category: