Warming has allowed mountain pine beetle to move into high elevation whitebark pine forests. This, coupled with the exotic white pine blister rust, has had devastating results. Restoration has focused on blister rust resistance. However, the tree must also cope with a warmer, drier climate and increasing beetle pressure. Our questions were: (1) has the beetle selected against trees struggling under warmer drier conditions leaving trees better adapted to current and future conditions? (2) has genetic diversity been affected? We located mature survivors and mature trees killed by the beetle. Survivors and killed trees were cored. Needles of survivors were collected for DNA analysis. From trees just under the minimum diameter beetles attack, we collected cores and needles. The smaller cohort was used a surrogate for the ‘general population’ pre-beetle selection. All living trees were rated for blister rust. We used inter simple sequence repeats (ISSR) to generate genetic profiles of survivor and general population trees. Cluster analyses and PCA were used to detect differences between survivors and general population trees. Tree ring width and density were used to build predictive models of surviving and beetle-killed trees using climate conditions as explanatory variables.
Results/Conclusions
Cluster analysis of ISSR data indicate that mountain pine beetle has selected for certain genotypes over others. Survivors and a few general population trees clustered distinct from other general population trees indicating distinct genetic differences among survivors and those selected by the beetles. However, survivors did not cluster as one group but rather two indicating multiple factors may account for resistance. Core analyses are ongoing and will be used along with genetic data to determine if survivors exhibit genetic and phenotypic profiles indicative of adaptation to climate change. Additionally, rust severity data is being incorporated into correlation analyses and will be presented.