Seed viability of alpine species: variability within and among years

Abstract

Percent of seeds filled for alpine grasses and seed viability and longevity for alpine grasses and forbs with different life history and physiological traits were evaluated for seeds collected in 1983, 1984, 1985, and 1986 on the Beartooth Plateau, Mont. Significant (p<0.001) differences existed in the percent of seeds filled for grass species and in the seed viability of both grass and forb species among years. The high variability in seed viability among years is attributed to the severe and unpredictable nature of the environment. Seed viability differed among species within most years. In general, grass species had lower and more variable seed viability than forb species. Low seed viability years for the grass species coincided with low seed fill years, indicating poor seed development. Longevity of seeds collected in 1983 varied among species and was related to seed characteristics and the overall life history and physiological traits of individual species. Seed longevity of species with life history and physiological traits typical of late seral species was shorter than that of species with traits typical of early seral species.