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:Overall, changes in pattern of species richness may disrupt marine biodiversity and ecosystems, and impact commercial fisheries (Roessig et al. 2004; Worm et al. 2006; Cheung et al. 2008b).
Category: