Correlates of seed size in a subalpine meadow on the east part of the Tibet plateau

Abstract

:We test hypotheses that can account for the variation in seed size in a database of 229 species from a subalpine meadow on the east part of the Tibetan plateau. Information on seed mass, plant height, dispersal mode, onset of flowering, and family membership is included. We use general linear models to consider not only the primary correlations between seed size and each variable, but also overlap patterns among correlations to determine whether particular relationships arise as a result of indirect correlations through other variables. The strongest association of seed size is with family membership, and the variation accounted for by family membership overlaps with that accounted for by plant height, dispersal mode, and onset of flowering. Similarly, we find that there are overlaps in the seed-size variation explained both by plant height and dispersal mode and by plant height and onset of flowering. However, there is no association in the variation in seed size accounted for by plant height and onset of flowering. Family membership, plant height, dispersal mode, and onset of flowering have significant associations with seed size independently of the other variables measured. We cannot give a logical explanation for the relationship between seed size and onset of flowering.