Document: ERI-3-46-12

Niche differentiation between diploid and tetraploid snow buttercups (Ranunculus adoneus).

BAACK, E.J.*

University of California, Davis, CA 95616, U.S.A. ¹

Abstract:
Speciation due to chromosome doubling is a common process in flowering plants. However, ecological mechanisms allowing plants with doubled chromosomes to establish populations have received little empirical attention. I examined one putative mechanism, niche differentiation, in diploid and tetraploid seedlings of the alpine snow buttercup (Ranunculus adoneus: Ranunculaceae). In 1999 seedlings were collected from diploid and tetraploid populations in the Mosquito Range of Colorado and transplanted into two sites with diploid populations and two sites with tetraploid populations. Results of the first year of a reciprocal transplant experiment showed that tetraploid seedlings survived longer and developed primary leaves earlier than diploid seedlings. However, no niche differentiation was detected as seedlings did not show increased growth or survival when planted into a site with their home cytotype. The advantage to tetraploid plants in the early seedling stage could offset the reproductive disadvantages of being a minority cytotype in a population.

Keywords: Polyploidy; Alpine buttercup; reciprocal transplant

This abstract is being presented at: 3:15 PM in session:
Oral Session #63: Evolutionary Ecology.