JOHNSON, MONICA L.*, DAVID A. TAIT, and LOREEN ALLPHIN. Department of Botany and Range Science, Brigham Young University, Provo, UT 84602. - Ecological and genetic diversity in Draba burkei sp. nov. (Brassicaceae), a critically imperilled taxon.
Draba burkei sp. nov. (Brassicaceae) is a newly discovered
species from a narrow geographic range in Northern Utah, USA. The
species is known from only a few localities in the Wellsville and
Wasatch Mountains. The largest population of this extremely rare,
alpine species was compromised in order to make a safe ski run for the
2002 Winter Olympics, Men's Down-hill Event. Concern for the species
preservation has elucidated the need for more biological information,
as a foundation for development of management plans for this new, rare
mustard. Therefore, five long-term monitoring plots were established
representing the largest populations of the species and its entire
geographic range. One hundred individuals were randomly selected and
tagged in each population. Vegetative and reproductive data were
collected for tagged individuals at these sites including clump
diameter, number of inflorescences per plant, number of flowers per
inflorescence, etc. Soil characteristics and associated species were
also determined for each monitoring site. For reproductive studies,
fruits were collected from tagged individuals, and seed to ovule
ratios were calculated. Enzyme electrophoresis was performed to assess
genetic diversity within and among populations. Genetic variation at
15 allozyme loci was compared with morphological and reproductive
variation within and among populations. Draba burkei exhibited
much genetic variation, both within and among populations. All
populations showed unique alleles at several of the loci, likely due
to their geologic and elevational variation and their large geographic
separations. Populations also differed significantly for several
vegetative and reproductive traits. These differences once again are
likely due to elevation and geographic distribution. Because there is
a high degree of genetic differentiation and geographic isolation
between populations, they appear to be genetically drifting apart.
Key words: alloyzmes, conservation, demography, diversity, Draba, genetic variability