Biodiversity relevance

There was a higher IBR (i.e., the number of potential interactions between plant species and other organisms) of the total vegetation in fenced than in grazed plots (x̅fence=826, x̅grazed=759, Fig. 3A-4, Appendix A.5-6). When analysing plant functional groups separately, we found that herbs (x̅fence=37, x̅grazed=26, Fig. 3B) and non-fruit shrubs (x̅fence=190, x̅grazed=121, Fig. 3F) both had higher IBR in fenced plots. There were no differences between treatments for graminoids, ferns or fruit shrubs (Fig. 3C-E). In terms of minimum and maximum biodiversity, there were only small qualitative differences between treatments grouped by functional vegetation groups (Fig 4, Appendix A.6). Despite the wide age gradient of the exclosures (1950-2002), there was no age effect on vegetation composition, diversity, and IBR.