A secondary effect of early agriculture during the years of the Dust Bowl and Great Depression in the late 1920s and early 1930s was when homesteaders abandoned the unproductive land. The United States government bought up much of this land through the Land Utilization Program, with management eventually controlled by the United States Forest service and the Bureau of Land Management. During the drought years of the 1930s, these agencies re-vegetated some of these areas with non-native highly competitive vegetation such as smooth brome ("Bromus inermis") and crested wheatgrass ("Agropyron cristatum"). These plants served their purpose by re-vegetating and protecting the soil. But these invaders became great competitors and directly affected native vegetation. In some instances crested wheatgrass and smooth brome have forced out native vegetation, creating monoculture habitats. Monoculture habitats are not favored by sharp-tailed grouse, as they prefer sites with high heterogeneity. Hamerstrom (1939) was quoted as saying "More important than the individual cover plants is the fact that most of the nests of all species were in cover mixtures rather than pure stands."