title: Effects of open grazing and livestock exclusion on floristic composition and diversity in natural ecosystem of Western Saudi Arabia.
abstract: Livestock grazing is one of the main causes of rangeland degradation in Saudi Arabia. Fencing to exclude grazers is one of the main management practices used to restore vegetation and conserve biodiversity. The main objectives of this study were to investigate the changes in plant diversity and abundance, floristic composition and plant groups of the major life forms in response to thirty-five years of grazing exclosure in western Saudi Arabia. These vegetation attributes and palatability were compared in 30 sampling stands located in the excluded and grazed sites. Our results showed that livestock exclusion significantly increased covers, density and species richness of annuals, grasses, perennial forbs, shrubs and trees. Exclosure enhanced the abundance and richness of palatable species and depressed the development of weedy species. About 66.7% of the recorded species at the excluded site were highly palatable compared to 34.5% at the grazed site. In contrary, about 55.2% unpalatable species were found in the grazed site compared to 25.8% in the protected site. Jaccard's similarity index between the excluded and grazed sites showed lower values of 0.39%, 0.40% and 0.31% at levels of families, genus and species, respectively. The results suggest that establishing livestock exclusion may be a useful sustainable management tool for vegetation restoration and conservation of plant diversity in degraded rangelands of arid regions.
authors.affiliation: Department of Plant Production, King Saud University, PO Box 2460, Riyadh 11451, Saudi Arabia.
authors.forename: Saud L
authors.initials: SL
authors.lastname: Al-Rowaily
authors.affiliation: Department of Botany, Faculty of Science, Port Said University, Egypt.
authors.forename: Magdy I
authors.initials: MI
authors.lastname: El-Bana
authors.affiliation: Department of Biology, College of Science, University of Tabuk, Saudi Arabia.
authors.forename: Dhafer A
authors.initials: DA
authors.lastname: Al-Bakre
authors.affiliation: Department of Plant Production, King Saud University, PO Box 2460, Riyadh 11451, Saudi Arabia.
authors.forename: Abdulaziz M
authors.initials: AM
authors.lastname: Assaeed
authors.affiliation: Department of Botany and Microbiology, Faculty of Science, Cairo University, Giza 12613, Egypt ; Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Ahmad K
authors.initials: AK
authors.lastname: Hegazy
authors.affiliation: Department of Plant Production, King Saud University, PO Box 2460, Riyadh 11451, Saudi Arabia.
authors.forename: Mohammed Basharat
authors.initials: MB
authors.lastname: Ali
keywords: Fencing; Grazing impacts; Protection; Rangeland Steppes; Restoration