Coexistence of grazed and ungrazed patches increases plant and invertebrate functional diversity in a Mediterranean oak woodland

Background/Question/Methods Grazing is a global dominant land use affecting plant and associated animal communities with implications for biodiversity and ecosystem processes. In Mediterranean ecosystems grazing is a major ecological and evolutionary driver. Surprisingly, there is a considerable lack of information on the use of grazing as a tool to manage biodiversity in these ecosystems.We conducted a grazing exclusion experiment to assess if coexistence of grazing and grazing excluded areas would increase plant and invertebrate functional diversity in a Mediterranean evergreen oak woodland.

Results/Conclusions Plant and litter biomass was higher, and proportion of bare ground was lower, in ungrazed plots. Grazing affected functional diversity with legumes and invertebrate detritivores being more abundant in ungrazed plots. There were no differences between treatments in the number of species but there were plant species and invertebrate taxa recorded in grazed or ungrazed plots, only. Ant communities were functionally different between treatments with honeydew eaters associated with ungrazed, higher plant biomass plots and seed-eater and predator ant species associated with grazed, more open habitat, plots. Maintaining grazing and grazing excluded areas may increase habitat heterogeneity and promote functional diversity at the estate or landscape level. In systems where grazing is a dominant land use temporary exclusion of grazing patches may be a simple and viable way contributing to increase plant and invertebrate diversity.