Submitted to: Restoration Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 10, 2010
Publication Date: July 1, 2010
Citation: Parsons, M.C., Jones, T.A., Monaco, T.A. 2010. Genetic variation for adaptive traits in Elymus elymoides ssp. brevifolius Race C in the Northern Intermountain West, USA. Restoration Ecology. 19:460-469. Interpretive Summary: Bottlebrush squirreltail is an important bunchgrass for rangeland restoration in the northern Intermountain region, but its genetic amplitude has not been characterized. We evaluated 32 populations of race C, the predominant race of subspecies brevifolius in this region, for a variety of ecological traits in the greenhouse and field in order to ascertain the functional relationships among these traits. We found that populations that displayed large numbers of tillers and thin roots as greenhouse seedlings were most likely to be productive as mature plants in the field. To enhance restoration success, restoration practitioners should choose a race C plant material that originates from an elevation similar to that of their restoration site.
Technical Abstract: Elymus elymoides (Raf.) Swezey (bottlebrush squirreltail) and E. multisetus (J.G. Sm.) Burtt Davy (big squirreltail) are important components of sagebrush-steppe communities in the Intermountain West, USA. Elymus elymoides has diverged into 4 subspecies, and E. elymoides ssp. brevifolius includes 4 recognized geographically distinct races (A, B, C, and D). Of these 4 races, only race C is prolific in the northern Intermountain West, so we evaluated 32 race C accessions collected across this region. Our objectives were to assess the genetic diversity within the group for important ecological traits and to ascertain functional relationships among these traits. Evaluations were conducted in common environments in the field and greenhouse. We observed a positive correlation (r = 0.734) between greenhouse shoot and root biomass among accessions, suggesting a synergistic rather than a trade-off relationship. Correlations between biomass variables measured in resource-rich greenhouse and resource-limiting field environments were generally low and nonsignificant, suggesting that any trade-off between growth rate under non-limiting conditions and stress tolerance is weak. Nevertheless, tiller number and specific root length, as measured in the greenhouse, were often positively associated with biomass traits measured in the field. Accessions with higher greenhouse shoot mass had lower SLA (thicker leaves) (r = -0.429) and SRL (thicker-diameter roots) (r = -0.465). High-biomass accessions originating in more productive environments may require less root length to extract soil water and nutrients, but it may be disadvantageous to seed such plant material in low-resource environments for this reason.