Effects of grazing abandonment on functional and taxonomic diversity of Mediterranean grasslands

This paper analyses changes in species richness and functional trait diversity in response to grazing abandonment in Mediterranean grasslands, for five traits that are well connected to ecosystem function and community assembly: Plant Height, Specific Leaf Area, Seed Mass, Onset of Flowering and Growth Form. The impacts of land-use change on floristic composition and community weighted traits were measured along with soil fertility, bare soil cover and litter cover. Results reveal changes in the community average value of all analysed plant functional traits and a loss of functional diversity after abandonment in two of them, which is not accompanied by a change in species richness, indicating a loss of functional groups and a potential effect on the ecosystem functioning. Abandonment is accompanied by the disappearance of short species, prostrate or creeper growth forms and early flowering species, while tall species and graminoid forms increase, their greater inflammability predicting an increase in wildfire frequency and intensity. Seed Mass and Specific Leaf Area show a weak but significant signal, with abandonment favoring large-seeded species and small Specific Leaf Area. A decline in soil fertility after abandonment is also detected, probably related to the decreased nutrient recycling rate and litter decomposability. (C) 2012 Elsevier B.V. All rights reserved.