| Ecotypic differentiation, local adaptation, and phenotypic plasticity in survival, plant size, relative growth rates, active growth period, and flowering were investigated in reciprocal seed transplant and common garden experiments with Bromus carinatus, a native perennial bunchgrass. Eight sites with diverse habitats were selected along an elevational gradient from the Pacific coast to the 3050 m subalpine zone in the Sierra Nevada, California. Seeds from 10 to 20 randomly selected families at each site with 12 individuals per family were sown in a greenhouse. At each site seeds from the local population, an adjacent elevational population, and the coastal and subalpine populations were planted in a randomized complete block design.;In the greenhouse variation among and within populations in initial seed weight, timing of emergence and second leaf emergence, duration of emergence, juvenile and adult plant size, and relative growth rates in all traits increased at decreasing rates with increasing elevation of the source population. Timing of reproductive onset decreased with source elevation. In the field cumulative and age-specific survival rates, the increasing probability of survival with age, mean culm height, numbers of leaves and stems, relative height growth and leaf and tiller production rates, active growth period, and proportion of flowering individuals over three years increased curvilinearly with increasing site elevation and elevation of the source population and linearly with decreasing absolute difference in elevation and geographic distance from the site of origin.;Cumulative and age-specific survival rates over three years were greater in local than nonlocal populations. Local populations were taller with more leaves and tillers, greater relative height growth and leaf and tiller production rates, longer periods of growth, and a higher proportion of flowering individuals over three years than nonlocal populations across and among elevational sites. Among elevational sites local populations differed from populations from adjacent sites in mean plant height, relative height growth rates, and flowering.;Results from this study provide strong support for ecotypic variation, local adaptation, phenotypic plasticity, and genetic variation for phenotypic plasticity in survival, plant size, relative growth rates, duration of active growth, and flowering in Bromus carinatus along an elevational gradient. |
