Forest tree genetic risk assessment system: a tool for conservation decision-making in changing times
PARTNERS: North Carolina State University (NCSU), USDA Forest Service National Forest System Region 8 (Southern Region) and Region 6 (Pacific Northwest Region), USDA Forest Service Southern Research Station, USDA Forest Service Forest Health Monitoring Program
SUMMARY: A variety of threats, most importantly climate change and insect and disease infestation, will increase the risk that forest trees could experience population-level or species-level extinction. Species, however, differ in important traits such as life-history strategies and population dynamics, which could drive widely varying responses to potential threats. Determining how to prioritize species for management and conservation activities in the face of these threats will pose a particular challenge in species-rich regions. To address this challenge, a cooperating scientist with the Southern Research Station’s Eastern Forest Environmental Threat Assessment Center has developed a framework that allows managers to assess the relative risk of genetic degradation to forest trees affected by multiple threats.
This assessment framework serves as a tool for planning management activities and conservation efforts, for evaluating species’ genetic resources, and for detecting vulnerabilities. It has the advantage of accounting for multiple threats that may result in the most severe genetic impacts. Only by considering population-level extirpation as a synergistic process of external threats and intrinsic biological traits will we be able to make predictions of risk that approximate reality for most species.
Known as the Forest Tree Genetic Risk Assessment System (ForGRAS), the framework has been used by the Forest Service Southern and Pacific Northwest Regions to identify species at risk as a step towards developing management plans. The flexibility of this approach allows for its application at multiple scales and across any area for which data exist on the population dynamics and distribution of the species of interest.
EFETAC’S ROLE: The project is supported by EFETAC funding.
PROGRESS: The first phase of the project has been completed. Kevin Potter of North Carolina State University and collaborator Barbara Crane, Regional Geneticist for Region 8 (Southern Region) of the USDA Forest Service National Forest System, have developed the system to rank the relative risk of genetic degradation, from climate change and other threats, to 131 Southern Appalachian tree species. This included determining the forest tree traits of interest, the external threats to forest trees in the region, and the availability of data for assessing these traits and threats. Two documents have resulted: a user guide that outlines in detail how the assessment system works and provides results for the Southern Appalachians, and the spreadsheet containing information for 27 variables for each of the species, which was used to do the actual assessment.
The Forest Tree Genetic Risk Assessment System gives each species a rating for risk factors relating to (1) its intrinsic attributes, such as population structure, fecundity and seed dispersal mechanism, that may increase its vulnerability in the face of change, and (2) the external threats to its genetic integrity, including changing climate and insect and disease threats. (See figures below.) The factor scores are weighted and summed to give risk ratings for the species within a given region, which are ranked according to their overall susceptibility to genetic degradation.
The assessment system is ideal for other geneticists, land managers and policymakers who may have an interest in using the framework for assessing the relative risk to forest tree species in another region.
Work is ongoing to collect information on risk variables for tree species across the United States, to allow for eventual risk assessments of tree species in regions other than the Southern Appalachians. Additionally, researchers are using ordination approaches to cluster species with similar risk attributes into groups that may require similar management and conservation strategies.
Six species-intrinsic risk factors for genetic vulnerability are included in the assessment. Variables for each factor are noted here, along with whether higher values are expected to be associated with greater genetic vulnerability (↑) or less genetic vulnerability (↓), as outlined in the listed reference. Click image to enlarge.
Two species-external risk factors for genetic vulnerability are included in the assessment. Variables for each factor are noted here, along with whether higher values are expected to be associated with greater genetic vulnerability (↑) or less genetic vulnerability (↓), as outlined in the listed reference. Click image to enlarge.
Devine, W., Aubry, C., Miller, J., Potter, K.M., and Bower, A. 2012. Climate change and forest trees in the Pacific Northwest: guide to vulnerability assessment methodology. Olympia, Washington: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region. 49 p. http://ecoshare.info/wp-content/uploads/2012/04/CCFT_Methodology.pdf.
This research has been described in a number of presentations.
CONTACT: Kevin Potter, NCSU Department of Forestry and Environmental Resources, firstname.lastname@example.org or (919) 549-4071
Updated December 2012