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Question: What is the impact of grazing and/or afforestation on grassland diversity, species composition and cover parameters?

Location: Semi-arid Mediterranean grasslands of Jordan.

Methods: Vegetation. litter, bare soil and rock cover were compared among four management types - free grazing and protected from grazing with three levels of tree cover. Species composition. plant cover, species richness and evenness were used to evaluate differences in vegetation among management types. Species composition differences among management types were also investigated.

Results: Semi-arid Mediterranean grasslands harbour appreciable levels of plant biodiversity. Grazing did not affect plant diversity. indicating the high resilience against and adaptation to grazing: however. grazing affected species composition and cover parameters. Afforestation seems to protect soil through higher litter cover but its impact on plant biodiversity was negative and markedly affected species composition.

Conclusions: Neither protection from grazing or massive afforestation alone are sufficient for conserving biodiversity in this system. A management model is suggested where the landscape should be maintained as a mosaic of four management types: complete protection from grazing, grazing rotation, planting sparse trees in eroded areas and revegetating degraded areas using native, herbaceous and grazing tolerant species.