Redistribution of resources and land-use pattern in a semi-arid rangeland: The case of Bedouin sheep herders in the Northern Negev Desert, Israel.

摘要

This dissertation examines the relative contributions of Bedouin grazing management practices that impact vegetative and soil resources in the Northern Negev Desert of Israel. Landscape processes are used as cues by Bedouin shepherds to guide management decisions. Research showed that total carbon and nitrogen and net N mineralization had not increased in soils that were protected from grazing for six years. Grazed areas appear to have higher rates of net N mineralization than protected areas and this relationship is strongly associated with patch type and landscape position.; Chapter two examines the impact of livestock grazing on runoff, soil and nutrient erosion on an experimental rangeland in Lehavim, Israel. Inter-shrub spaces served as a source of materials that moved into shrub patches that retain water, sediments, and nutrients. Crust patches yielded 6.9% runoff in grazed areas and 6.4% runoff in ungrazed areas. Shrub patches yielded below 2% runoff. Two years of intensive grazing activity did not result in significant differences in runoff, soil and nutrient erosion rates. These results indicate that grazing did not diminish the hydrological functioning of this rangeland after two years.; The relative contribution of grazing management practices that drive vegetative and soil resources is critical for management of semi-arid shrub-land ecosystems. An examination of the spatial and seasonal distribution of grazing pressure across the landscape and its relationship to vegetation properties was conducted. Significant patterns of pasture use emerged as Bedouin shepherds distinguished among vegetation classes and selected grazing areas based on floristic composition rather than strictly on vegetative biomass.; Socio-ecological analysis of Bedouin herd management revealed historical and current political constraints as driving factors of Bedouin access to productive land resources. Despite these constraints, after thousands years of land use, grazing has become an important process that maintains soil quality and vegetation dynamics and is strongly influenced by social processes and herder management.