Maintaining genetic diversity within an endangered species is an important goal of conservation biology. However, the threat of disease to endangered plants has been neglected in past studies. Disease may cause plant numbers to decline andor the disease may reduce the genetic diversity within a population. An example is a white rust disease of the Menzies' wallflower, Erysimum menziesii, an endangered plant restricted to vanishing native dune communities along the northern California coast. Some populations of the plant suffer from the disease and, although the wallflower has been the object of extensive research, the destructive effect of the disease has not been investigated. Both ecological and genetic studies are required. This research will closely examine the relationship between the wallflower and its disease to assess if disease has caused the plant to become endangered or is keeping the plant from recovering. In addition, the genetic diversity within both the plant and pathogen populations will be measured for three years and this will provide an indication if diversity is being maintained during conservation or if there is any change in the genetic structure. Many aspects of this research are unique. It is a collaborative effort between The California Nature Conservancy, a conservation management organization, and Michigan State University, a traditional basic research institution. This partnership will provide needed cooperative effort between basic science and applied conservation. By combining genetic studies with population monitoring, management options specifically for Menzies'wallflower will be addressed. In addition, this approach will introduce a generalized strategy to assess the impact of disease on other endangered plants. The results will provide the basis for future predictive mathematical models which can be used to evaluate how specific conservation activities would affect recovery. From this, conservationists will be able to choose between management options. Included with these applied aspects is the basic study of plant disease in natural populations. This project will expand the discipline by introducing a new type of model system, one with different attributes than those currently under study.
