Seed transfer zones for a native grass Festuca roemeri

A common-garden study of Festuca roemeri (Pavlick) E. B. Alexeev (Poaceae) revealed substantial genetic variation within and among 47 populations from throughout its range in the Pacific Northwest, US, for growth, fitness, phenological, and morphological traits. Using climatic and physiographic variables, genetic patterns over the landscape were examined through principal component and regression analysis. Elevation and latitude of the seed source, and to a lesser extent temperature and precipitation, explained a significant proportion of the genetic variation, suggesting that observed variation was associated with adaptation to local environments. Most plants from the Willamette Valley exhibited poor growth and survival, perhaps due to inbreeding. Festuca roemeri variation clustered into seed transfer zones corresponding to Level III ecoregions, and one zone was further subdivided. High-elevation populations separated from lower-elevation populations but did not cluster into a single seed zone. Seed transfer zones reported here provide a guide for plant community restoration efforts using this species.