Biology Theses and Dissertations

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    Elucidating the Macro- and Micro-evolutionary Relationships of the Federally Listed Endangered Species Agalinis acuta (Orobanchaceae)
    (2010) Pettengill, James Beaton; Neel, Maile C; Behavior, Ecology, Evolution and Systematics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Agalinis acuta (Orobanchaceae) is a federally listed endangered plant species native to the mid-Atlantic and northeastern coastal plains of the United States. Due to morphological ambiguity and molecular similarity between A. acuta and Agalinis tenella and Agalinis decemloba a conservation priority is to determine whether A. acuta represents an evolutionarily distinct entity worthy of protection under the Endangered Species Act. To resolve this question, a phylogenetic study was first conducted based on seven chloroplast DNA loci and the nuclear DNA locus ITS from 79 individuals representing 29 Agalinis species. A study evaluating the utility of those cpDNA loci and three analytical techniques for the purpose of DNA barcoding was also conducted. The phylogenetic study indicated that A. acuta was perhaps evolutionarily indistinct from A. decemloba and A. tenella. Based on the results of subsequent analyses of 21 microsatellite loci and morphological data evaluated under myriad species concepts, A. acuta, A. decemloba, and A. tenella best represent a single species with two subspecies; the former two putative species would constitute a subspecies called A. decemloba ssp. decemloba and A. tenella would be A. decemloba ssp. tenella. With evolutionary distinct entities described, a phylogeographic study was conducted to determine the extent to which historical processes rather than contemporaneous events can explain extant patterns of genetic and phenotypic diversity within A. decemloba. The dispersal of a few individuals out of southern refugial populations likely represents the process through which northern populations were established; however, recent anthropogenic effects that disproportionately affected northern populations may have also contributed to extant patterns of diversity. Neutral or adaptive explanations for phenotypic variation among populations are also investigated. The conservation implications of population genetic analyses were assessed for members of A. decemloba ssp. decemloba. Despite the evidence that this taxon is self-compatible, the high levels of inbreeding and low levels of heterozygosity are of such a magnitude in certain populations that genetic factors may be negatively impacting fitness. Because of the small effective population sizes and degree of isolation, all populations should be managed to reduce the risk of extinction associated with demographic and environmental stochasticity.
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    THE EVOLUTION, PHYLOGEOGRAPHY, AND CONSERVATION OF THE GOLDEN LANGUR (Trachypithecus geei) IN BHUTAN
    (2005-04-15) Wangchuk, Tashi; Inouye, David W; Biology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The golden langur (<i>Trachypithecus geei</i>) is an endangered endemic species of primate in Bhutan. Conservation of this species is addressed here through phylogeographic and habitat management tools. I hypothesize that rivers and mountains in Bhutan isolated a population of capped langurs (<i>Trachypithecus pileatus</i>) and that this population later speciated into the morphologically distinct golden langur. <i>Trachypithecus</i>, the genus to which both capped and golden langurs belong, spread north from a paleo-refuge in south China and <i>Semnopithecus</i> (grey langurs) spread east and northward from a refuge in south India. My results show that these two genera both arrived in Bhutan but could not mix since the Sunkosh River and Pelela range form a biogeographic barrier. Likewise, a population of capped langurs isolated from parental populations by rivers speciated into the distinct golden langur. I conducted field surveys covering the entire range of langurs in Bhutan, confirming the distribution and isolating barriers among the three langurs. Grey langurs and golden langurs are isolated from each other by the Sunkosh River and Black Mountain range in west Bhutan. In the east, the Manas river system (Manas-Mangde-Chamkhar) served as a barrier between golden and capped langurs. However, this barrier has been broken in the last 30 years due to the construction of bridges over the Chamkhar river. A hybrid zone was found and the implications are discussed. A cyt b phylogeny showed the grey langur of Bhutan grouping into a distinct clade with other congenerics of Semnopithecus. The south-Indian clade of grey langurs is more ancient, with the Bhutan and Nepal grey langurs having diverged later. The golden and capped langur from Bhutan grouped with <i>Trachypithecus</i> from South East Asia. Finally, I explore conservation of golden langur habitat in Bhutan and estimate available habitat at 3,089 km2 and an estimated population of about 6,000 individuals. I also find that the most viable strategy for conservation of langur habitat is to give ownership of the forests to local people, with monitoring by the Department of Forestry.