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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Demographic perspectives on the rarity and persistence of two mariposa lilies (Calachortus) from southern British Columbia

Miller, Michael 10 April 2008 (has links)
No description available.
22

Intraspecific Phylogeography of Cycladenia humilis (Apocynaceae)

Last, Mariana P. 10 November 2009 (has links) (PDF)
Cycladenia humilis (Apocynaceae) is a rare perennial herb native to western North America and has a fragmented distribution in California, Utah, and Arizona. Populations in Utah and Arizona are federally listed as threatened, while there is no conservation status applied to California populations. Using genetic (three chloroplast and two nuclear DNA loci) and morphological characters, intraspecific variation between populations of C. humilis and current taxonomic conventions were assessed. Nested Clade Phylogeographic Analysis and Bayesian phylogenies were used to assess patterns within C. humilis and supported three main population groupings: a northern California, southern California, and Colorado Plateau group. The northern California populations represent a distinct group and include populations from the Santa Lucia Mountains contrary to current classifications. The southern California group consistently includes populations in the San Gabriel and Inyo Mountains and was unique from any other region. The Colorado Plateau represents a group distinct from all other groups. The resilience of C. humilis on the Colorado Plateau to human threats remains unknown, but based on its frequency being comparable to California and our findings that considerable genetic variation exists within the species and within populations on the Colorado Plateau, we recommend that the threatened status of C. humilis be lifted.
23

Comparative analysis of community and population levels of organization in the rare grass, Achnatherum hendersonii

Binney, Elizabeth P., January 1997 (has links) (PDF)
Thesis (Ph. D.)--University of British Columbia, 1997. / Includes bibliographical references (leaves 127-133).
24

Vištytgirio botaninio- zoologinio draustinio Raudonosios knygos būklės tyrimai / Survey of condition of plants of Lithanian Red list in Vištytgiris botanical-zoological reserve

Kartavičiūtė, Gintarė 16 June 2014 (has links)
Įvertinti Raudonosios knygos augalų paplitimą, būklę, bei kaitą ir pasiūlyti priemones jų būklei ir paplitimui pagerinti. / To assess the distribution of plants of red list, their condition and changes in Vištytgiris botanical-zoological rezerve; and identify measures to improve their condition and spread.
25

Antropogeninio poveikio įtaka Vidzgirio botaninio draustinio retiems augalams / Antropogenic Effect To The Rare Plants In The Botanical Conservation Area Of Vidzgiris

Staniulytė, Erika 16 August 2007 (has links)
Magistro baigiamąjį darbą sudaro 57 puslapiai. Jame yra 8 lentelės, 31 paveikslėliai, 44 literatūros šaltiniai ir 13 priedų. Magistro darbe tiriama antropogeninio poveikio įtaka Vidzgirio botaninio draustinio retiems augalams. Darbo objektas- reti augalai augantys Vidzgirio botaninio draustinio teritorijoje. Darbo tikslas- įvertinti retų augalų dinamiką per pastaruosius metus ir ieškoti priemonių jų išlikimui. Darbo metodai- retų augalų gausumui nustatyti naudojomės Botanikos instituto parengta monitoringo metodika (Parengta Zigmanto Gudžinsko 2001 m. Botanikos institutas, Floros ir geobotanikos laboratorija). Aprašant augavietę kiekvienos rūšies augalų gausumas ir padengimas vertinami balais pagal Braun- Blanquet skalę . Atlikus tyrimus ir įvertinus retų augalų paplitimą nustatyta, kad 7 iš 11 rastų retų augalų auga antropogeninio poveikio zonoje Jų augavietės yra šalia upelio, piliakalnio ir mokomojo tako. Šios vietos yra gausiai lankomos. Reti augalai augantys Vidzgirio botaniniame draustinyje nukenčia nuo intensyvios rekreacijos, kirtimų, šiukšlių. Tyrimų metu nustatyta, kad sumažėjo tamsialapio skiautalūpio individų skaičius. Pagausėjo plačialapės klumpaitės individų skaičius. Rastos naujos retų augalų augavietės. Norint užtikrinti saugomų augalų augaviečių stabilumą, ypač vertinguose miško sklypuose reikia taikyti tokį patį ūkininkavimo režimą, kaip I grupės miškuose, visoje draustinio teritorijoje vengti bet kokių introdukuotų augalų rūšių sodinimo, sureguliuoti... [toliau žr. visą tekstą] / Final master degree work of University, 57 pages, 31 figures, 8 tables, 36 references, 44 appendix. Master degree work cover the studies of antropogenic effect to the rare plants, which are growing in the botanical conservation area of Vidzgiris. The object of research- rare plants growing in conservation area of Vidzgiris. The aim of research- to evaluate dynamic over the recently years of rare plants and to seek measures for their survival. These methods were used while writing the work: for the identifying superfluity of rare plants the monitoring methods were applied prepared by the Botanical Institute (prepared by Zigmantas Gudžinskas 2001, Botanical Institute, in Flora and Geobotany laboratory). By using descriptive method it was evaluated the superfluity and coating of every sort of plant for populations association using Braun- Blanquet rates scale. After research and evaluating spread of rare plants instituted that 7 of 11 rare plants are growing in the zone of antropogenic effect. They growing places are near the stream, mound and educational path. Rare plants in the botanical conservation area of Vidzgiris are influencing by intensive recreation, deforestation, rubbish. At the time of research estimated that number of Epipactis atrorubens has decreased. Number of Cypripedium calceolus has increase. Were found new places were rare plants can grow. That to secure protected rare plants growing places is need to fit farming mode like in the I group forest... [to full text]
26

The evolutionary origins of Erigeron trifidus, a rare plant in Alberta

Burke, Jennifer L., University of Lethbridge. Faculty of Arts and Science January 2005 (has links)
The present study analyzed the evolutionary history of Erigeron trifidus Hook. by addressing two main questions: 1) Is the current hypothesis of the origin of the species by hybridization between E.compositus and E.lanatus supported by molecular data? and 2)Is the species monophyletic? An analysis of uni-and-biparentally inherited molecular markers from three species throughout the range of E.trifidus yielded data that supports the hybridization hypothesis. First, a restriction site analysis of cpDNA revealed 4 haplotypes. In most cases, cpDNA haplotypes were the same as in E.lanatus, suggesting E.lanatus as the maternal parent. Sequencing and cloning the nuclear ETS region revealed the presence of multiple repeat types in most individuals sampled. This further supports the hybrid origin hypothesis in that E.trifidus contained only repeat types present in one or the other of the putative parents. In addition, E.trifidus displayed the highest percentage of intrainidividual repeat type polymorphism, a common trait of hybrid species. Erigeron trifidus populations collected in the northern region appear to be monophyletic as they all exhibited a particular pattern of repeat type variation, a pattern absent in Ram Mountain and Waterton Lakes National Park populations. As E.lanatus has never been recorded from Ram Mountain, it is likely that the populations identified as E.trifidus are instead a different agamospermous variant of E.compositus. In Waterton Lakes National Park, populations of E.trifidus are thought to be the product of local hybridization but the identity of the putative parents remains uncertain. Therefore, E.trifidus is concluded to be polyphyletic. / viii, 66 leaves : ill. (some col.) ; 28 cm.
27

The ecological genetics of rarity : a study of genetic structure, inbreeding and seed bank dynamics in a rare annual plant /

McCue, Kimberlie A., January 1997 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.
28

The ecological genetics of rarity a study of genetic structure, inbreeding and seed bank dynamics in a rare annual plant /

McCue, Kimberlie A., January 1997 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.
29

Spatial analysis of Helianthus schweinitzii (Schweinitz's sunflower), an endangered species endemic to the Piedmont of North Carolina

Smith, Tammy Capps. January 1900 (has links)
Thesis (M.A.)--The University of North Carolina at Greensboro, 2008. / Directed by Roy Stine; submitted to the Dept. of Geography. Title from PDF t.p. (viewed Apr. 13, 2010). Includes bibliographical references (p. 58-64).
30

Monitoring of Foraging Sites for Ungulates within Alpine Plant Communities and Establishment of Long-Term Monitoring Plots for Rare Castilleja parvula var. parvula in the Tushar Mountains, Utah

Shipp, Heather 14 April 2022 (has links)
The Tushar Mountains of Utah provide essential alpine habitat to a variety of flora and fauna, including 27 endemic plant species and several ungulates (mountain goats, deer, elk, cattle). These ungulates were observed throughout two growing seasons and field analyses were conducted to assess foraging selection. Overall, most ungulates, especially large nursery herds, tended to prefer foraging amongst alpine regions within the Bullion volcanic of the Tushars, which is characterized by denser vegetation than the Belknap volcanic region. Mountain goats and deer were most frequently observed foraging within the Tushar alpine habitat; however, elk and domestic cattle were also observed. Mountain goats preferred foraging at higher elevations than other ungulates and shared the most dietary overlap with deer. Out of the 27 plant species endemic to this region, only Castilleja parvula var. parvula, commonly known as the Tushar paintbrush, was encountered frequently utilized by ungulates. This plant species was also observed being eaten by a variety of rodents and lagomorphs. Long-term monitoring plots were established in four different populations of C. parvula var. parvula across the Bullion volcanic range of the Tushars. These plots were revisited on a yearly basis and used to ascertain demographic data, which will shed light on population trends over time. A variety of different measurements were used to better understand the biology and habitat requirements of this rare plant species. Although the four monitored populations share many similarities, they each have their own site characteristics, local densities, relative plant communities, and potential threats. Further monitoring is necessary to better understand trends and assess the level of the various threats to C. parvula var. parvula populations.

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