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Management of white-tailed deer (Odocoileus virginianus) populations has traditionally been based on a density-dependent model of population growth in which deer morphology and demography vary with deer density. Density-dependence appears to operate through declines in diet quality as a result of foraging induced changes in the vegetation. This population model is based on research conducted in forested regions of the United States. The model may not apply to white-tailed deer inhabiting the semiarid, shrub-dominated rangelands of southern Texas. In a 9-year study of enclosed deer populations managed at densities ranging from 12 - 50 deer/km2, birth rates, survival rates, population growth rates, fawn and yearling growth rates, and antler size did not vary with deer density. Furthermore, a high-quality pelleted supplement improved every morphological and population parameter measured, demonstrating that nutrition limits deer populations in this region. The apparent contradiction of weak density dependence in populations that are nutritionally limited is explained by characteristics of the forage resources. South Texas rangelands have a high biomass of browse that is moderate in nutritional quality. Shrubs are a vast food resource that is sufficient for maintenance of adult deer but not for production. Furthermore, shrubs have chemical, physical, and structural attributes that limit the impact of large herbivore foraging, thus enabling persistence over a wide range of deer densities. Precipitation in this semiarid environment causes a flush of herbaceous vegetation which provides the high-quality forage necessary for reproduction. Deer persist in this environment because high adult survival bridges periods of poor reproduction caused by low precipitation. Implications of these findings for deer management in southern Texas are that managers may have more flexibility than previously thought in managing deer densities, that high adult survival is critical to sustain populations, and that management actions to improve diet quality should increase productivity of deer populations.