Abstract Detail

Recent Topics Posters

Jennings, Linda, P. [1], Whitton, Jeannette [1].

Genetic variation and ecological differentiation between two Southern Utah endemics; US Federally Threatened Townsendia aprica and a closely related congener, T. jonesii var. lutea (Asteraceae)..

Southeastern Utah is a hot spot of species richness and rarity, and therefore provides a unique opportunity to study rare, endemic plants. Of the 145 plant species considered endangered or threatened in Utah, Townsendia aprica is one of 22 species receiving protection under the US Federal Endangered Species Act. Soon after Townsendia aprica was first described in 1968, it was listed as a Federally Threatened Species and assigned a G1/S1 rank in 1985. Careful documentation has expanded the known range from roughly 384 km2 to 3200 km2, with many of these populations comprising fewer than 100 individuals. It is presumed, due to small population sizes and isolation, that outcrossing populations of Townsendia aprica will have low genetic variation and that different populations will show fixed differences as a result of genetic drift. Eight informative isozyme loci were resolved, to gain insight into the distribution of genetic variation within T. aprica and compared these with genetic variation in its closest congener, Townsendia jonesii var. lutea. While this congener grows just west of T. aprica in a smaller and more restrictive non-overlapping range, the two taxa have similarly restricted ranges and are similar in morphology (both possess yellow colored rays, a novel ray flower color in the genus). Both taxa also have high genetic variation for rare endemics (He = 0.35-0.40). Despite these similarities, isozyme data reveal that the two species are genetically and ecologically distinct. Analysis of isozyme data supports the recognition of two groups corresponding to the two taxa, while analysis of soils on which the two species occur reveal differences in soil texture and micronutrients. Even with so many similarities between these two taxa, significant differences in allele frequencies, soil habitat, and distribution in Utah have helped distinguish these two very similar taxa.

1 - University of British Columbia, Botany Department, 3529-6270 University Boulevard, Vancouver, British Columbia, V6T 1Z4, Canada

Keywords:
rare endemic
Asteraceae
isozyme
threatened species
Utah
genetic variation.

Presentation Type: Poster
Session: 32-164
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM
Abstract ID:1134