Perevolotsky, A. ;  
Sterenberg, M. ;  
Osem, Y. ; 
Ungar, E. D. ;  
Gutman, M. ;  
Hadar, L. ;  
Kigel, J.

This paper discusses the relationship between heavy grazing and rangeland vegetative diversity in Israel. This study aimed to test the ecological cost of intensifying livestock production on rangelands as well as to improve the understanding of the role grazing can play in the management of nature reserves in Mediterranean environments. The impact of heavy grazing, well above the regular norms, was assessed in 3 ecosystems: basaltic grasslands; semiarid hills and calcareous rocky habitats. In all cases, heavy grazing did not affect vegetation diversity but generated a significant change in the composition of the community, favouring low stature species, geophytes and early flowering species. Grazing exclusion, however, led to a sharp decrease in species richness. The ecological process behind these observations is the release of low species from the competitive dominance of tall species. The resilience of the vegetative community to heavy grazing is, most likely, due to its persistent seed bank and long grazing history.