Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [139]-160).

Thesis (M.S.)--Boise State University, 2009. / Title from t.p. of PDF file (viewed June 7, 2010). Includes abstract. Includes bibliographical references (leaves 31-41).

Thesis (Ph.D.)--University of Hong Kong, 2000. / Includes bibliographical references. Also available in print.

Thesis (Ph. D.)--University of Chicago, Committee in evolutionary biology, Jun. 2003. / Includes bibliographical references (p. 227-244). Also available on the Internet.

Thesis (Ph. D.)--Ohio University, 2005. / Title from PDF t.p. (viewed Jan. 26, 2007). Includes bibliographical references (p. 157-170).

[Truncated abstract] Wild radish (Raphanus raphanistrum L.), an outcrossing annual plant, is one of the most widespread and successful colonising weeds in the Australian wheat belt. It was introduced accidentally during the latter part of the 19th century, apparently independently through the major ports of southern Australia. The widespread success of wild radish, and therefore the likelihood of distinct populations, gives us the opportunity to study the colonizing process with adaptation in annual outbreeding species, and to explore their genetic diversity. The aims of this thesis were to study the genetic diversity of wild radish and to investigate which factors are important in its success. After an initial review of the literature (chapter 2), the thesis describes experiments where genetic variation between and within populations was compared at 55 sites in transects across the wheat belt and high rainfall zones of temperate Western Australia (chapter 3). In chapter 4, variation in life history traits was compared with variation in AFLP molecular markers. The role of seed dormancy in the survival of the species was examined in chapter 5, and variation in the oil content of seeds and their fatty acid composition was examined in chapter 6. Finally, the results were discussed in chapter 7 with special reference to the adaptive value of outcrossing in annual weeds. The results suggest that wild radish has evolved to fit the Australian environment. However, measurement of 14 morphological and phenological characters showed that in most cases within site variation was much greater than that between sites. Most of the variation between sites was associated with geoclusters, a name given to zones of similar environmental conditions in regard to rainfall and temperature. Thus plants from areas with high rainfall and low temperature produced longer, wider pods with more segments, heavier seeds and flowered later than plants from more arid areas.

published_or_final_version / Ecology and Biodiversity / Doctoral / Doctor of Philosophy

Astragalus oniciformis Barneby is a xerophyte of the sagebrush deserts of central Idaho. It is a narrow endemic of the upper Snake River Plains where it inhabits stabilized, aeolian sand deposits over Quaternary basalt flows. The objective of this study was to determine the levels and distribution of genetic differentiation within and among populations of Astragalus oniciformis. Fifteen individuals from each of eight populations, chosen from throughout the range of the species, were selected for their accessibility, density of individuals, and large population size. Two disjunct eastern populations selected for this study have been separated from the continuous western populations for 3600 years by an eight-mile wide, inhospitable lava flow. Inter-simple sequence repeats (ISSR) were chosen as the marker to assess genetic differentiation. Two primers were selected that yielded 40 loci, all of which were polymorphic in A. oniciformis. In an analysis of molecular variance (AMOVA), 88.69 percent of the variation was significantly attributed to variation within populations. The differentiation between the two disjunct populations and the western populations was insignificant. High gene flow (Nm=3.91-3.93) and a low percent deviation from Hardy-Weinberg equilibrium due to population subdivision (G[subscript st]=0.113-0.1134) were found among populations of A. oniciformis. These results suggest that current threats to this species, ranging from plant community changes due to changing fire patterns, habitat alteration from livestock grazing, and habitat loss from agricultural development have not yet affected the genetic diversity of this species. Preservation of the numerous, large populations and the high gene flow will help insure that the levels of genetic diversity found in Astragalus oniciformis will not decrease. / Graduation date: 2002

No description available.

Despite their ecological and economic importance, the majority of plant species and their conservation status are poorly known. Only 4% of plants have been assessed globally and listed on the IUCN Red List of Threatened Species; and without plant conservation assessments, many plant species will not feature in conservation planning. Herbarium collection information can significantly increase the number of plant conservation assessments. Thus, the aims of this thesis were: (1) to investigate how the quality of herbarium-based conservation assessments can be optimised; (2) to assess the extent to which herbarium-based conservation assessments reflect the reality on the ground; and (3) to scientifically validate genetic and spatial underpinning of IUCN criteria. Preliminary range-based assessments of the Leguminosae of Madagascar achieved a result consistent with the final conservation rating for over 95% of species when using up to fifteen herbarium specimens. Bioclimatic modelling of range shifts based on future climate change predicted that, in the worst case scenario, up to one third of endemic Leguminosae in Madagascar will be threatened with extinction over the next 100 years. An analysis of the population structure of species of Delonix s.l. (Leguminosae) showed that combining spatial analysis with population genetic data provides a more complete picture of landscape-level population dynamics and the impacts on conservation status. Moreover, range-wide genetic analysis of AFLP markers for four species of Delonix demonstrated a genetic basis for IUCN categories distinguishing between threatened and non-threatened species. Although genetic data are currently not often incorporated in conservation assessments, they are crucial in making accurate management decisions and creating effective action plans for conservation. Only by using all available scientific resources can informed conservation decisions be made and the survival of plants and their associated ecosystems be ensured.