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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.
1

Some Ordination and Classification Methods in Plant Ecology

Chen, Chih-Kang 08 1900 (has links)
<p> This project studies the applicability of two ordination methods, principle component analysis and correspondence analysis, and one classification method, mode analysis, for a specific ecological data set. The differences between techniques are discussed and the results are compared.</p> / Thesis / Master of Science (MSc)
2

The investigation of regional ecology using 2km x 2km scale botanical distribution data

Lawley, Sue January 2010 (has links)
Tetrad vascular plant data from Staffordshire (VC 39), accumulated 1995 - 2009, were analysed using Two Way Indicator Species Analysis and Principal Components Analysis, explored using GIS, to examine major floristic distribution patterns. Environmental data were also examined using Redundancy Analysis. The strongest floristic trend was a human influence axis, arranged south—north, with the south being most anthropocentric and the north having a high proportion of semi-natural habitats. Indicator species for different parts of the County showed a corresponding strong biogeographic element, with ‘Southern-temperate’ and ‘Boreo-temperate’ characteristics in south and north respectively. The next most important factor in the distribution of plant species in Staffordshire was habitat quality and richness, which separated intensively-managed farmland from areas with seminatural habitats and from human influenced urban areas. Environmental variables associated with the main division in the data were mainly climate and altitude and the extent of developed land. Historic field patterns, identified by Staffordshire County Council, were associated with semi-natural habitats, linking an historical landscape characterisation with vascular plant analysis for the first time in the UK. The investigation set out to characterise and classify spatial units in terms of biodiversity importance, and to produce an objective ecological classification of the Staffordshire region based on botanical and physical features. The resulting classification characterises different areas of the County in terms of plant species composition, and has many potential applications in terms of nature conservation strategy development, targeting of resources and monitoring. A further aim was to facilitate the selection of indicator species for high quality habitats – the study has enabled revision of Staffordshire’s axiophyte plant list. Both the ecological classification and indicator species will be of strategic value because the information provided is authenticated by being based on objective analysis of a wide range of data. In Staffordshire, further work is required to develop environmental data, especially an effective dataset for hedges, while comparison of the data with historical botanical data could provide further information about the County’s previous environment. The techniques developed in the study could be used more widely to: produce of lists of key species, provide information for environmental modeling, climate change monitoring, target nature conservation activity, and to develop landscape strategies.
3

Inuit ethnobotany and ethnoecology in Nunavik and Nunatsiavut, northeastern Canada

Clark, Courtenay 12 1900 (has links)
Les habitats uniques de l'écotone forêt boréale-subarctique dans le nord du Canada subissent les contrecoups du changement climatique. Combinés aux effets de la mondialisation, les changements environnementaux touchent les Inuits de cette région et imposent des contraintes importantes sur leur mode de vie traditionnel, ce qui a des répercussions sur leur langue et les savoirs qui l'accompagnent. Cette étude compare deux aspects de l’ethnobiologie inuite : a) les noms et les utilisations des plantes par les Inuits de Nain, Nunatsiavut, suivis par une comparaison des utilisations avec la communauté inuite de Kangiqsualujjuaq, Nunavik, et b) une analyse des types de lieux ou d’habitats que les Inuits reconnaissent et nomment. Des interviews semi-dirigés ont été menés à Nain, Nunatsiavut et à Kangiqsualujjuaq, au Nunavik. Les plantes mentionnées sont utilisées comme aliment, thé, médecine, combustible, construction, nettoyage, et autres utilisations. Les deux communautés ont utilisé un nombre égal de plantes, avec des proportions équivalentes de taxons vasculaires/invasculaires, de formes de croissance (habitus), et d’espèces par catégorie d'utilisation. Les éléments du paysage les plus fréquemment rapportés sont d’ordre topographique, hydrologique ou écologique. L’intégration des concepts inuits, quant aux plantes et au paysage, à ceux de la science occidentale peut améliorer notre compréhension de l'écologie subarctique, aider à impliquer les acteurs locaux dans les décisions sur le développement de leur territoire et, conséquemment, modifier l'aménagement du territoire ainsi que les initiatives de conservation de la biodiversité. Ces concepts ont également des répercussions sur les stratégies d'adaptation face aux changements climatiques. / Unique habitats of the boreal-subarctic ecotone in northeastern Canada are being impacted by climate change. Combined with effects of globalization, changing environmental conditions are causing Inuit of this region to see significant strains on their traditional lifestyle and on the language and knowledge that go with it. This study compared two aspects of Inuit ethnobiology: we compared plant names and uses from two Inuit communities and examined what kinds of places or habitats Inuit recognize and name. Semi-structured interviews were conducted in Nain, Nunatsiavut and Kangiqsualujjuaq, Nunavik, by showing interviewees (mostly Elders) plant specimens or photos of the region. Plants were used for food, tea, medicine, fuel, construction, cleaning, and other uses. Both communities used equal numbers of plants, with equivalent proportions of vascular/non-vascular taxa, growth forms, and species per use category. Forty-three species were reported in each community, for a total of 78 species from 39 families. Despite high overlap in species distributions, only half of all species were shared, reflecting community-specific bodies of traditional knowledge, or perhaps an overall decline in ethnobotanical knowledge use. The most frequently reported landscape features were topographical, hydrological, and ecological (i.e. plant associations and animal habitats). Some Inuit categories reflected their significance to traditional Inuit lifestyle (e.g. ‘berry-patch’, ‘seal-place’), aiding navigation and resource finding. Integrating Inuit conceptions of plants and landscape with those of contemporary science can improve our understanding of subarctic ecology, help involve local stakeholders in sustainable development discussions, and inform land-use planning, biodiversity conservation initiatives, and climate change adaptation strategies.
4

Inuit ethnobotany and ethnoecology in Nunavik and Nunatsiavut, northeastern Canada

Clark, Courtenay 12 1900 (has links)
Les habitats uniques de l'écotone forêt boréale-subarctique dans le nord du Canada subissent les contrecoups du changement climatique. Combinés aux effets de la mondialisation, les changements environnementaux touchent les Inuits de cette région et imposent des contraintes importantes sur leur mode de vie traditionnel, ce qui a des répercussions sur leur langue et les savoirs qui l'accompagnent. Cette étude compare deux aspects de l’ethnobiologie inuite : a) les noms et les utilisations des plantes par les Inuits de Nain, Nunatsiavut, suivis par une comparaison des utilisations avec la communauté inuite de Kangiqsualujjuaq, Nunavik, et b) une analyse des types de lieux ou d’habitats que les Inuits reconnaissent et nomment. Des interviews semi-dirigés ont été menés à Nain, Nunatsiavut et à Kangiqsualujjuaq, au Nunavik. Les plantes mentionnées sont utilisées comme aliment, thé, médecine, combustible, construction, nettoyage, et autres utilisations. Les deux communautés ont utilisé un nombre égal de plantes, avec des proportions équivalentes de taxons vasculaires/invasculaires, de formes de croissance (habitus), et d’espèces par catégorie d'utilisation. Les éléments du paysage les plus fréquemment rapportés sont d’ordre topographique, hydrologique ou écologique. L’intégration des concepts inuits, quant aux plantes et au paysage, à ceux de la science occidentale peut améliorer notre compréhension de l'écologie subarctique, aider à impliquer les acteurs locaux dans les décisions sur le développement de leur territoire et, conséquemment, modifier l'aménagement du territoire ainsi que les initiatives de conservation de la biodiversité. Ces concepts ont également des répercussions sur les stratégies d'adaptation face aux changements climatiques. / Unique habitats of the boreal-subarctic ecotone in northeastern Canada are being impacted by climate change. Combined with effects of globalization, changing environmental conditions are causing Inuit of this region to see significant strains on their traditional lifestyle and on the language and knowledge that go with it. This study compared two aspects of Inuit ethnobiology: we compared plant names and uses from two Inuit communities and examined what kinds of places or habitats Inuit recognize and name. Semi-structured interviews were conducted in Nain, Nunatsiavut and Kangiqsualujjuaq, Nunavik, by showing interviewees (mostly Elders) plant specimens or photos of the region. Plants were used for food, tea, medicine, fuel, construction, cleaning, and other uses. Both communities used equal numbers of plants, with equivalent proportions of vascular/non-vascular taxa, growth forms, and species per use category. Forty-three species were reported in each community, for a total of 78 species from 39 families. Despite high overlap in species distributions, only half of all species were shared, reflecting community-specific bodies of traditional knowledge, or perhaps an overall decline in ethnobotanical knowledge use. The most frequently reported landscape features were topographical, hydrological, and ecological (i.e. plant associations and animal habitats). Some Inuit categories reflected their significance to traditional Inuit lifestyle (e.g. ‘berry-patch’, ‘seal-place’), aiding navigation and resource finding. Integrating Inuit conceptions of plants and landscape with those of contemporary science can improve our understanding of subarctic ecology, help involve local stakeholders in sustainable development discussions, and inform land-use planning, biodiversity conservation initiatives, and climate change adaptation strategies.
5

Patterns of aquatic macrophytes in the boreal region: implications for spatial scale issues and ecological assessment

Alahuhta, J. (Janne) 01 November 2011 (has links)
Abstract Eutrophication and global warming are increasingly causing deterioration of aquatic ecosystems, and boreal freshwaters are especially vulnerable to these changes. Anthropogenic pressures and landscape characteristics influencing the functioning and structure of ecosystems vary with spatial scale (grain size i.e. study unit and extent i.e. study area). This emphasises that the understanding of spatial scale is a vital element when studying species distribution patterns. Moreover, spatial scale is often neglected in ecological assessments, in which the degree of ecological integrity of an ecosystem is assessed using selected biological groups. One of these groups is aquatic macrophytes. The aims of this thesis were (i) to study the distribution and richness of aquatic macrophytes in the boreal region in Finland at multiple scales and (ii) to evaluate the performance of ecological assessment metrics selected for Finnish lake macrophytes. The spatial extent at which aquatic macrophytes were studied had an important influence on the patterns found. Climatic factors associated with latitudinal and altitudinal gradient determined macrophytes at broad extent, although the patterns changed at finer regional extent. Moreover, this strong effect of climate could lead to the widening of distribution ranges of helophytes in boreal catchments during the 21st century due to the climate change. Many of these species have already widened their range limits during the previous century and increasing temperatures may create new niches for vegetation to colonize. Lake macrophyte richness, turnover and quality metrics showed a clear relationship with nutrient concentration in waters at landscape and regional extent. Helophytes and metrics were positively or inversely negatively related to nutrients, whereas species turnover and other life-form groups had a unimodal or non-significant response to nutrient availability. In addition, land use (agricultural and urban areas and forestry ditch drainage) influenced macrophytes directly through shore morphology changes and indirectly through water quality. Macrophytes were also explained at various scales by area and depth, which were related to habitat heterogeneity, and aquatic plants responded to water ionic and electrical characteristics (pH, alkalinity and conductivity). Ecological quality metrics of macrophytes appeared to be scale dependent, since land use adjacent to the lake shoreline had a higher influence on the metrics compared to land use of the whole catchment. However, the scale-related pattern in the effect of land use was not congruent between metrics, as the Trophic Index showed poorer performance compared to the proportion of type-specific species and Percent Model Affinity. This was presumably due to lack of helophytes in the species pool used and to reference values which were defined across lake types in the Trophic Index. Uneven performance of the metrics derived from different biological groups suggests that an approach integrating multiple lines of evidence on ecological status appears most feasible for assessment of the overall lake status. / Tiivistelmä Vesistöjen rehevöityminen ja ilmastonmuutos heikentävät vesiekosysteemien laatua, ja boreaaliset sisävedet ovat erityisen alttiita näiden uhkatekijöiden aiheuttamille muutoksille. Ihmistoiminnan aiheuttamien muutoksien ja luontaisten maisematekijöiden merkitys vesiekosysteemien toimintaan ja rakenteeseen vaihtelee mittakaavan (tutkimusyksikön ja -alueen) mukaan. Kuitenkin spatiaalisen mittakaavan merkitys on usein unohdettu ekologisissa arvioinneissa, joissa selvitetään ekosysteemin luonnontilaisuutta eri biologisilla lajiryhmillä. Vesikasvit ovat yksi usein käytetty biologinen ryhmä järvien ekologissa arvioinneissa. Tämän tutkimuksen tarkoitus on (i) tutkia vesikasvien levinneisyyttä ja runsautta Suomessa useissa mittakaavoissa, ja (ii) arvioida ekologisten luokittelumuuttujien toimivuutta järvien vesikasveilla eri mittakaavoissa. Mittakaava, jossa vesikasveja tutkittiin, vaikutti merkittävästi saatuihin tuloksiin. Leveysasteeseen ja korkeuteen liittyvä gradientti määritti vesikasvien levinneisyyttä alueellisessa mittakaavassa. Lisäksi ilmaston voimakas vaikutus vesikasveihin voi johtaa niiden levinneisyysrajojen laajenemiseen, koska ilmastonmuutos saattaa luoda edullisemmat kasvuolosuhteet kasvillisuudelle tällä vuosisadalla. Monet vesikasvilajit ovat jo levinneet pohjoisemmaksi 1900-luvulla, ja lämpötilojen nousu voi lisätä ekolokeroita vesikasvien levittäytymiselle. Vesikasvien runsaus, lajimäärä ja luokittelumuuttujat olivat selkeästi yhteydessä vesien ravinteisuuteen maisemallisessa ja alueellisessa mittakaavassa. Ilmaversoisilla vesikasveilla ja luokittelumuuttujilla oli positiivinen tai käänteisesti negatiivinen suhde ravinteisiin, kun taas lajimäärä ja muut vesikasvien kasvumuodot olivat unimodaalisessa tai merkityksettömässä yhteydessä ravinteisuuteen. Lisäksi maankäyttö, erityisesti maatalous, kaupunkiasutus ja metsäojitus, vaikutti vesikasveihin suoraan rantavyöhykkeen morfologisin muutoksin tai epäsuorasti ravinteisuuden kautta. Vesikasvien levinneisyyttä ja runsautta selitti myös pinta-ala ja syvyys, jotka liittyivät elinympäristön heterogeenisyyteen, sekä veden fysikaalis-kemialliset ominaisuudet, kuten pH, alkaliniteetti ja sähkönjohtokyky. Ekologiset luokittelumuuttujat olivat riippuvaisia mittakaavasta, koska rantavyöhykkeen läheisellä maankäytöllä oli suurempi merkitys muuttujille kuin koko valuma-alueen maankäytöllä. Kuitenkin mittakaavan merkitys vaihteli eri muuttujien välillä, kun referenssi-indeksi osoitti heikompaa vastetta maankäyttöön eri mittakaavoissa kuin tyyppilajien suhteellinen osuus ja prosenttinen mallin samankaltaisuus. Tämä luultavasti johtui siitä, että referenssi-indeksissä ilmaversoiset vesikasvit puuttuivat tutkittavista lajeista ja referenssiarvot olivat yhteiset riippumatta järvityypistä. Eri biologisiin ryhmiin perustuva luokittelujärjestelmä ilmensi hyvin vaihtelevasti ekologista laatua, minkä vuoksi eri muuttujia yhdistävä menetelmä, joka arvioi vesimuodostuman kokonaistilaa, on toteuttamiskelpoisin lähestymistapa boreaalisissa järvissä.

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