Plant diversity of grazed and reforested Mediterranean rangelands

Rangelands cover a large area in the Mediterranean region but are largely degraded due to their improper grazing management. The aim of this study was to investigate the effect of various management practices applied for restoration of degraded Mediterranean rangelands on plant diversity. The research was conducted in rangelands of Lagadas county, in North Greece, dominated by evergreen shrublands. The management practices studied were: moderate grazing, overgrazing, control (banning of grazing), partial and full reforestation with pines (Pinus pinaster). Three transects were established on each management practice. Plant cover was recorded along each transect using the line-point method and species composition was calculated. Additionally, species presence /absence was measured using 10 quadrats per transect. The recorded species were classified into five a priori groups (trees, shrubs, grasses, legumes, forbs). Furthermore, three plant diversity indices (Shannon-Wiener, evenness and species richness) were calculated for each transect. The five management practices had high plant cover, with the exception of the overgrazed one. The composition of the vegetation however differed in terms of the dominant plant group in each practice. As far as plant diversity is concerned, the moderately grazed practice had the highest values followed by the control while the full reforestation had the lowest. It is concluded that the various management practices for restoration of degraded Mediterranean rangelands affect differently plant species composition and diversity. However moderate grazing can contribute to restoration of plant diversity without resorting to other management practices such as pine plantations.