Viewpoint: a theoretical basis for planning woody plant control to maintain species diversity.

Abstract

Range improvement practices have been criticized by scientists and the public because of negative impacts on biodiversity. I present a conceptual model based on ecological theory for designing and planning woody plant control to maintain plant and wildlife species richness and diversity. Broad areas of rangeland have been impacted by overgrazing by livestock and attempted brush control in a manner that has resulted in dense woody plant communities that are resistant to natural disturbances such as fire. State-and-transition models of vegetation dynamics predict these biotic assemblages to be temporally stable and not responsive to successional trends. Cultural energy input in the form of woody plant control is required to change the vegetation configuration of these ecosystems. Anthropogenic input conceptualized and designed based on the intermediate disturbance hypothesis can maximize landscape diversity and may result in a landscape mosaic that supports greater species richness, provides increased forage for livestock, and enhances habitat for many wildlife species. A problem with this approach is that continuing inputs are required to maintain the selected landscape architecture. Development of models to predict the effects of woody plant control patterns on biodiversity will enable range managers to implement management strategies that maintain or increase plant and vertebrate species richness and diversity.