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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.
31

Risk för kontinuitetsglapp och förlust av biologisk mångfald i Solnas ekmiljöer

Olsson, Erik January 2011 (has links)
Den här studien undersöker kontinuiteten, vitaliteten, exponeringen och möjliga naturvårdsåtgärder i Solnas ekmiljöer. Enligt det 16:e miljökvalitetsmålet "ett rikt växt och djurliv" ska den biologiska mångfalden bevaras och nyttjas på ett hållbart sätt för nuvarande och framtida generationer. Gamla ekar har visat sig hysa en hög biologisk mångfald, men tyvärr minskar estånden av jätteträd kontinuerligt i Sverige samtidigt som föryngringen går långsamt eller i värsta fall helt avstannat. Åsikterna om jätteekarnas minskning verkar enstämmiga och bero på kontinuitetsglapp, upphörd hävd, igenväxning, plantering av gran på gamla odlingsmarker, brist på skötsel och ny bebyggelse i urbana miljöer. Kontinuiteten studerades genom att undersöka fördelningen mellan värdefulla ekar och ekefterträdare i hela Solnaområdet samt i fyra bestämda ektrakter. Kriteriet för god kontinuitet var 15 % värdefulla ekar och 85 % ekefterträdare. För att bedöma ekarnas vitalitet studerades andelen permanent döda grenar i trädkronan och för att bedöma ekarnas exponering struderades hur stor andel av trädkronan som täcktes av omgivande trädkronor. I varken hela Solnaområdet eller i trakterna observerades god ekkontinuitet. I hela Solnaområdet mår ekefterträdarna procentuellt sett sämre i samtliga vitalitetsklasser jämfört med de värefulla ekarna. För ekarnas exponeringstillstånd över hela Solnaområdet hade ekefterträdarna samma procentuella fördelning som de värdefulla ekarna när det gällde halvöppen exponering, men utöver det var ekefterträdarna jämförelsevis sämre exponerade. En viktig naturvårdsåtgärd för ekefterträdarna är att öka deras exponering, vilket kan göras med hjälp av frihuggning, slåtterhävd eller beteshävd.
32

Oustee powerlessness, pragmatism, and potential : conservation-induced displacement in central India

Beazley, Kim Rachael January 2011 (has links)
No description available.
33

Historical resource use and ecological change in semi-natural woodland : western oakwoods in Argyll, Scotland

Sansum, Philip Andrew January 2004 (has links)
This thesis investigates the ecological history of western oakwoods in the Loch Awe area,Argyll, Scotland. By combining historical evidence for human use of woodland resources with palaeoecological evidence for past ecological change the influence of man on the current condition of biologically important semi-natural woods is assessed. A chronology of human activities relevant to the woodland ecology of the study area is assembled from estate papers and other documentary sources. Vegetation change during the last c. 1000 years is elucidated by pollen analysis of radioisotope dated sediments from small hollows located within three areas of western oakwood believed to be ancient. The results are related to current condition and the hypothesis that the species composition of the woods exhibited temporal stability in the recent past is tested. Mechanisms of change culminating in the modem species compositions of the woods are suggested by synthesizing independent findings from historical and palaeoecological approaches. The documentary record indicates management in the 18th and 19th centuries to supply oak bark and coppice wood for commercial purposes. In the 20th century woodland use has been relatively minor except as a grazing resource. In the period before 1700 AD the woods were used for wood for local domestic needs and to shelter livestock. The palaeoecological record indicates a lack of stability in species composition during the last millennium. Relatively diverse woods still containing natural features such as old-growth were transformed in the medieval period into disturbed open stands depleted in natural features. Declining productivity was locally alleviated by the introduction of new modes of exploitation around or prior to 1700 AD. The current condition of the woods, rather than being the direct result of an economic design, is the consequence of post-disturbance biotic processes following the abandonment of management in the late 19th century. The findings are related to the conservation of the wider western oakwood resource.
34

Conditions that define a riparian zone in southeastern Arizona

Jemison, Roy Leonard, January 1989 (has links)
Thesis (Ph. D. - Renewable Natural Resources)--University of Arizona, 1989. / Includes bibliographical references (leaves 57-62).
35

The "Save the Bush" programme : government action or political delay? /

Hart, Phillip A. January 1991 (has links) (PDF)
Thesis (M. Env. St.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1992. / Includes bibliographical references (leaves 60-64).
36

Plant population dynamics and conservation in wooded hay-meadows - effects of intensified management /

Wallin, Lotta, January 2007 (has links)
Diss. (sammanfattning) Uppsala : Univ., 2007. / Härtill 4 uppsatser. Med sammanfattning på svenska.
37

The human-nature connection: increasing nature relatedness, environmental concern, and well-being through education /

Nisbet, Elizabeth K. L. January 1900 (has links)
Thesis (M.A.) - Carleton University, 2005. / Includes bibliographical references (p. 58-76). Also available in electronic format on the Internet.
38

The impacts of land development on ecological conservation in Hong Kong /

Lung, Hoi-yan. January 2000 (has links)
Thesis (M. Sc.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 146-156).
39

Conservation encounters : NGOs, local people, and changing cultural landscapes /

Sundberg, Juanita R. January 1999 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 319-344). Available also in a digital version from Dissertation Abstracts.
40

Area prioritization for optimal conservation planning

Fuller, Trevon Louis. January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2009. / Title from PDF title page (University of Texas Digital Repository, viewed on Sept. 14, 2009). Vita. Includes bibliographical references.

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