WWETAC Projects

Project Title:  Comparative life history traits and fitness indicators of common native and invasive, non-native plant species in western Washington and Oregon

Principal Investigators:  Timothy B. Harrington, Research Forester, USDA Forest Service, PNW Research Station, Olympia Forestry Sciences Laboratory;  David H. Peter, Ecologist, PNW Research Station, Olympia Forestry Sciences Laboratory

tharrington[at]fs.fed.us

Collaborators:   Shawna Bautista, Invasive-Plant Program Manager, USDA Forest Service Region 6; Invasive Plant Coordinators for Ranger Districts on several Region 6 National Forests

Key Issues/Problem Addressed:              

An understanding of life history traits of common native and invasive, non-native plant species is essential for predicting both the susceptibility of plant communities to invasion and the potential success of treatment strategies for preventing and mitigating invasions and restoring native communities. Unfortunately, parameter estimates of life history traits for common native and invasive, non-native plant species of western Washington and Oregon are largely unavailable, scattered throughout the scientific literature, or estimated from populations outside of the Pacific Northwest. Therefore, the objective of this project is to populate a species-by-life-history-trait matrix of common native and invasive, non-native plant species of western Washington and Oregon using existing information from the scientific literature. Species will be grouped by life form (i.e., graminoids, forbs, shrubs, and trees), stature, and other variables to identify the life history traits likely to determine competitive outcomes when the native and invasive, non-native species co-occur.
               
Setting and Approach:  

A reference list of 50-100 Pacific Northwestern native and invasive, non-native plant species of parallel life form and stature will be developed as the primary scope for the project. Using information from seven plant community studies of the Olympia Forestry Sciences Laboratory located throughout the study region, abundance estimates of plant species were analyzed to identify a candidate list of 50 species common to typical forest and non-forest terrestrial communities and to group the species by life form and stature. This list will be expanded where appropriate to refine the grouping by relevant physiognomic classes (e.g., crown shape, foliage density, etc.) and to include competing native and invasive, non-native species for each grouping. The candidate list will then be reviewed by project cooperators for relevance to current efforts to manage and restore invaded plant communities. A literature review and synthesis will be conducted to compile parameter estimates of key life history traits for each species on the reference list, and to develop methods for integrating trait information into indicators of species’ fitness likely to determine competitive outcomes when native and invasive, non-native species co-occur.

Impacts/Applications:  

Quantification of the life history traits and their integration into indicators of species’ fitness will provide a foundation for testing hypotheses regarding invasion resistance of plant communities of the Pacific Northwest. The resulting journal article will provide an important contribution to the invasive-plant science literature. Sharing the database of life history traits and fitness indicators by species on the worldwide web is likely to stimulate new research with other invasive-plant scientists. By collaborating with the USFS Region 6 Invasive Plant Program Manager on this project, the fitness-based approach for predicting competitive outcomes is likely to be relevant to projects currently underway to manage and restore invaded plant communities.

WWETAC ID:      FY11NG94