The pastoral resources in eastern Sudan are changing under the combined impact of increasing anthropogenic activities such as clearance of natural vegetation and the effect of state policies that favour crop farming against pastoralism. Remotely sensed data are used to detect spatial and temporal changes from 1979 to 2009 in the land use/land cover (LULC) across three study sites. Areas of natural vegetation have been reduced from 26.1% in 1979 to 12.6% in 1999 and further to 9.4% in 2007. The majority of this reduction went into agricultural land. Local knowledge of pastoralists on their perceived changes in plant species is obtained. Major LULC trends are progressive degradation and loss of grazing areas, loss of biodiversity and depletion of other ecological support provided by natural vegetation. Declining rainfall, land clearance due to agricultural expansion, overgrazing and herbicide applications by crop farmers are identified as underlying forces changing plant species in the region. The study revealed that pastoralists have considerable knowledge and experience in dealing with degradation and climate variability. However, pastoralists are marginalized in decisions concerning expansion of large-scale agriculture at the expense of pasture land. Their lack of education and other basic services restricts the pastoralists' potential to adapt to the new situation.