Date of Award:
5-1-1998
Document Type:
Thesis
Degree Name:
Master of Science (MS)
Department:
Biology
Committee Chair(s)
Paul G. Wolf
Committee
Paul G. Wolf
Committee
Vincent J. Tepedino
Committee
Eugene W. Schupp
Abstract
Arctomecon californica (the Las Vegas bearpoppy) is endemic to gypsum outcrops of the northern Mojave Desert. Native habitat of this plant in the Las Vegas Valley has been severely fragmented, while relatively undisturbed, unfragmented habitat still exists in the Lake Mead National Recreation Area. I studied the reproductive ecology and population genetic structure of this rare plant. Comparisons were then drawn between fragmented and unfragmented habitat. Arctomecon californica flowers are mostly self-incompatible, and require a pollen vector for successful seed production. Evidence of pollinator limitation was found in both habitat types, but plants in fragmented habitat were much less successful reproductively. Plants at study sites in the fragmented habitat were generally larger, having more inflorescences, flowers, and fruits than those in unfragmented habitat. However, plants at the site in unfragmented habitat produced significantly more seeds per fruit. The number and diversity of pollinators were much higher in unfragmented habitat. Specialist bees commonly found visiting poppy flowers in unfragmented habitat were absent from study sites in fragmented habitat. The importance of unfragmented, continuous natural habitat to the reproductive biology, pollinator community, and maintenance of gene flow among populations is discussed. Allozyme data from seven loci for 16 populations indicate high levels of genetic variability. Nei's genetic identity and GST values indicate populations in fragmented habitat appear to be more differentiated with increasing geographic distance. Populations in unfragmented habitat show no relationship between geographic distance and genetic identity. Three indices of genetic variation were significantly lower for populations in fragmented habitat. However, there was little evidence of increased inbreeding, as indicated by fixation indices, for any population. Habitat fragmentation is discussed as a possible contributing factor to reduced levels of genetic variation in populations in the Las Vegas Valley.
Recommended Citation
Hickerson, Laura L., "The Reproductive Ecology, Demography, And Population Genetic Structure of Arctomecon californica Torrey & Fremont (Papaveraceae) in Fragmented and Unfragmented Habitat" (1998). Biology. 651.
https://digitalcommons.usu.edu/etd_biology/651
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