Genetic diversity has rarely been the focus of study in species at risk in Canada. <i>Tradescantia occidentalis</i> is one of 157 species listed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC 2005a). This species is nationally threatened due to the limited number of populations, their geographic isolation from each other and from the main distribution in the United States of America, and habitat loss. The National Recovery Team for Plants at Risk in the Prairie Provinces and the Alberta Western Spiderwort Recovery Team have called for research into the habitat requirements, demography, and genetic diversity of <i>T. occidentalis</i> in Canada. As a result, this study was designed to address the following objectives: 1) to conduct an inventory of the Canadian populations, 2) to investigate intra- and interpopulation genetic diversity in <i>Tradescantia occidentalis</i>, and 3) to provide recommendations for the conservation management of this species. <p>Information on demography and plant communities in <i>Tradescantia occidentalis</i> habitats indicated that the numbers of individuals in the Saskatchewan and Manitoba populations were similar to previous surveys; however, the Alberta population was significantly larger in number than prior estimates, indicating population growth. Taxonomic lists were prepared for each province in habitats with and without <i>T. occidentalis</i>. Community types, as separated by RA analysis, differed by province and not by association with <i>T. occidentalis</i>. Euphorbia esula, an invasive species in Canada, was observed in the Saskatchewan and Manitoba populations but was absent in Alberta. <p> Using amplified fragment length polymorphisms (AFLPs), genetic diversity was assessed at the intra- and interpopulation levels. Relatively low levels of intrapopulation variation were observed in Saskatchewan and Alberta, while higher levels were found in Manitoba. Gene flow via pollen or propagule transfer may account for higher genetic diversity among the closely situated Manitoba populations. The lack of correlation between dendrogram topology and geographic distribution suggests panmixia in all populations. Levels of intrapopulation diversity were low to moderate depending on primer combination used, indicating that populations are isolated within each province. <p>Information on population demography and genetic diversity are important within a conservation context. The large number of individuals within each population and the perceived increase in some populations suggest that the existing populations of <i>Tradescantia occidentalis</i> are relatively stable. Although levels of genetic diversity are low in Saskatchewan and Alberta compared to Manitoba, it appears that all populations are adapted to their local environments based on their apparent size and stability. The most viable conservation strategy for this species is in situ protection. This should include controlling invasive plant species, monitoring grazing, and preventing further habitat fragmentation. Ex situ methods must also be explored. Transplantation of individuals from one population to the next may not be a successful conservation strategy due to the moderate level of population differentiation. Alternatively, it is recommended that a seed bank from each population be implemented in case of a drastic population decline.

Genetic diversity has rarely been the focus of study in species at risk in Canada. <i>Tradescantia occidentalis</i> is one of 157 species listed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC 2005a). This species is nationally threatened due to the limited number of populations, their geographic isolation from each other and from the main distribution in the United States of America, and habitat loss. The National Recovery Team for Plants at Risk in the Prairie Provinces and the Alberta Western Spiderwort Recovery Team have called for research into the habitat requirements, demography, and genetic diversity of <i>T. occidentalis</i> in Canada. As a result, this study was designed to address the following objectives: 1) to conduct an inventory of the Canadian populations, 2) to investigate intra- and interpopulation genetic diversity in <i>Tradescantia occidentalis</i>, and 3) to provide recommendations for the conservation management of this species. <p>Information on demography and plant communities in <i>Tradescantia occidentalis</i> habitats indicated that the numbers of individuals in the Saskatchewan and Manitoba populations were similar to previous surveys; however, the Alberta population was significantly larger in number than prior estimates, indicating population growth. Taxonomic lists were prepared for each province in habitats with and without <i>T. occidentalis</i>. Community types, as separated by RA analysis, differed by province and not by association with <i>T. occidentalis</i>. Euphorbia esula, an invasive species in Canada, was observed in the Saskatchewan and Manitoba populations but was absent in Alberta. <p> Using amplified fragment length polymorphisms (AFLPs), genetic diversity was assessed at the intra- and interpopulation levels. Relatively low levels of intrapopulation variation were observed in Saskatchewan and Alberta, while higher levels were found in Manitoba. Gene flow via pollen or propagule transfer may account for higher genetic diversity among the closely situated Manitoba populations. The lack of correlation between dendrogram topology and geographic distribution suggests panmixia in all populations. Levels of intrapopulation diversity were low to moderate depending on primer combination used, indicating that populations are isolated within each province. <p>Information on population demography and genetic diversity are important within a conservation context. The large number of individuals within each population and the perceived increase in some populations suggest that the existing populations of <i>Tradescantia occidentalis</i> are relatively stable. Although levels of genetic diversity are low in Saskatchewan and Alberta compared to Manitoba, it appears that all populations are adapted to their local environments based on their apparent size and stability. The most viable conservation strategy for this species is in situ protection. This should include controlling invasive plant species, monitoring grazing, and preventing further habitat fragmentation. Ex situ methods must also be explored. Transplantation of individuals from one population to the next may not be a successful conservation strategy due to the moderate level of population differentiation. Alternatively, it is recommended that a seed bank from each population be implemented in case of a drastic population decline.

Cattle grazing has been a historic use of rangelands in Utah since Pioneer settlement in the mid 1800's. Wright fishhook cactus is a small globose cactus endemic to an area of 280,000 ha in south-central Utah and was listed as endangered in October of 1979, by the U.S. Fish and Wildlife Service (USFWS). By 2010, concerns were expressed that soil compaction in proximity to the cactus posed a threat to this species, though there was no empirical data to support such concern. In order to assess the impact of cattle traffic on Wright fishhook cactus, we used an imprint device to simulate a cow track's impact. We applied a treatment of either zero, one, or four hoof imprints within 15 cm evenly of 146 cacti within the same population cluster on the same day. We monitored subsequent plant survival as well as reproductive success. Each cactus in the study was visited multiple times and all developed seed was collected. We found that cattle traffic of any amount had no effect on plant survival or seed production and therefore concluded that cattle traffic poses no threat to Wright fishhook cactus. The status of this cactus yields no justification for changing the historic land management use of cattle grazing on these rangelands. Seedbank abundance and location has not been examined for any species within the genus Sclerocactus. Over a one-day period, we took 500 soil samples from various locations near the cactus and potential nurse-plants. We found that approximately 1% of annual seed production makes it into the seedbank, a number in line with other species in the Cactaceae family. Seedbank densities were highest immediately adjacent to, and downslope from, parent plants. Understanding the dynamics of the seedbank of this species could lead to more informed management practices.

abstract: Amsonia kearneyana is an endangered herbaceous plant endemic to a small area of the Baboquivari Mountains in southern Arizona. It exists in two distinct habitat types: 1) along the banks of a lower elevation ephemeral stream in a xeroriparian community, and 2) a higher elevation Madrean oak woodland on steep mountain slopes. Half of the largest known montane population (Upper Brown Canyon) was burned in a large fire in 2009 raising questions of the species capacity to recover after fire. This research sought to understand how the effects of fire will impact A. kearneyana's ability to recruit and survive in the burned versus unburned areas and in the montane versus xeroriparian habitat. I compared population size, abiotic habitat characteristics, leaf traits, plant size, and reproductive output for plants in each habitat area for three years. Plants in the more shaded unburned montane area, the most populated population, presented with the most clonal establishment but produced the least amount of seeds per plant. The unshaded burned area produced more seeds per plant than in the unburned area. Lower Brown Canyon, the xeroriparian area, had the fewest plants, but produced the most seeds per plant while experiencing higher soil temperature, soil moisture, photosynthetically active radiation, and canopy cover than the montane plants. This could indicate conditions in Lower Brown Canyon are more favorable for seed production. Despite ample seed production, recruitment is rare in wild plants. This study establishes germination requirements testing soil type, seed burial depth, temperature regimes, and shade treatments. Trials indicate that A. kearneyana can germinate and grow in varied light levels, and that soil type and seed burial depth are better predictors of growth than the degree of shade. Finally, this study examined the law, regulation, policy, and physiological risks and benefits of a new management strategy and suggests that "conservation by dissemination" is appropriate for A. kearneyana. Conservation by dissemination is the idea that a protected plant species can be conserved by allowing and promoting the propagation and sale of plants in the commercial market with contingent collection of data on the fate of the sold individuals. / Dissertation/Thesis / Masters Thesis Plant Biology 2015