How can we maintain and restore biodiversity in a changing world? My research explores drivers of plant and lichen diversity at multiple scales in both natural and restored systems.
I use botanical field studies across large geographic areas, often in combination with remote sensing techniques, to examine the relative influences of management practices, landscape context, disturbance, and the local environment on communities. My research is grounded in the natural history knowledge and experience I have gained over many years working as a field botanist and ecologist in several regions of North America.
Currently, I am working in collaboration with the USDA Forest Service’s Regional Ecology Program to analyze interactive effects of fire severity, historical disturbance regimes, and spatial disturbance heterogeneity on plant communities in the Sierra Nevada.
I envision my research program as part of a larger movement to broaden conservation management and restoration ecology into a predictive science, where tools are available to help managers use landscape context, site environment, and plant functional traits to guide practices.
Questions that guide my research past and present:
What is the relative importance of landscape and local factors for plant diversity?
Plant communities can be influenced by both the local environment and the surrounding landscape, but how does their relative importance vary? I have found that species with different life histories (i.e., habitat specialists vs. generalists) may respond to unique drivers. In Ozark grasslands, the richness of conservative, habitat specialist species is positively related to habitat patch size and connectivity, while the richness of generalist species richness is more strongly related to soil characteristics.
How do plant and lichen functional traits respond to landscape context and management activities? Can functional differences between early successional species and late-successional species be used to inform management and restoration practices?
Plant functional traits can provide key information about how plants respond to the environment. I have tested whether functional traits explain plant community responses to habitat connectivity and the local environment in Ozark glades. I am also interested in functional differences between early and late successional plant species, which could have implications for ecological restoration. I am investigating how community assessment metrics used by restoration practitioners relate to plant functional traits, which are widely used by ecological researchers as a community assessment tool. Linking these frameworks can potentially strengthen connections between basic and applied ecology.
What factors cause structural shifts in plant communities, such as woody encroachment in grasslands? How can we prevent shifts that threaten biodiversity and restore degraded habitats?
Woody vegetation is expanding into grassland and savanna habitats in many parts of the world, but the causes of encroachment are incompletely understood. Using historic aerial photos, I studied whether management efforts (prescribed fire and mechanical thinning) have been effective for maintaining historic open grassland habitats in the Missouri Ozarks. I found evidence that thresholds characterize encroachment patterns; encroachment may proceed more rapidly after reaching a critical level of woody cover.
What factors shape the abundance, diversity and distributions of biological soil crust lichens?
Soil-dwelling lichens are an important component of biological soil crusts (the living, breathing skin of the earth), and contribute significantly to biodiversity in arid and semi-arid regions. These organisms play important ecological roles, such as preventing wind erosion and the invasion of exotic grasses. They have been little studied, in part because of their cryptic nature, and their distributions and environmental niches are often poorly understood. I have worked with researchers at Oregon State University and the Idaho Bureau of Land Management on studies of soil crust lichen communities in sagebrush country of central Oregon. I am also investigating relationships between soil crust cover, soil resource availability, and plant diversity in Ozark sandstone glades.