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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.
481

The impacts of herbivores and humans on the utilisation of woody resources in conserved versus non-conserved land in Maputoland, northern KwaZulu-Natal, South Africa

Gaugris, Jerome Yves, January 2008 (has links)
Thesis (Ph. D.)--University of Pretoria, 2008. / Title from PDF title page (viewed on Nov. 11, 2008). Includes bibliographical references.
482

Applications of solid-state 15N NMR spectroscopy to the study of nitrogen cycling in sub-tropical forest plantations

George, Laurel. January 2008 (has links)
Thesis (Ph.D.) -- University of Western Sydney, 2008. / A thesis submitted to the University of Western Sydney, College of Health and Science, School of Natural Sciences, in fulfilment of the requirements for the degree of Doctor of Philosophy. Includes bibliographical references.
483

Primary succession of lianas in an Amazonian floodplain forest /

McManus, Erin Michael. January 2003 (has links)
Thesis (M.S.)--Wake Forest University. Dept. of Biology, 2003. / Includes bibliographical references (leaves 44-47).
484

Native forest pathogens may facilitate persistence of Douglas-fir in old-growth forests of northwestern California /

Hawkins, Ashley E. Unknown Date (has links)
Thesis (M.A.)--Humboldt State University, 2009. / Includes bibliographical references (leaves 37-42). Also available via Humboldt Digital Scholar.
485

Growth of tropical rain forest trees as dependent on phosphorus supply tree saplings differing in regeneration strategy and their adaptations to a low phosphorus environment in Guyana = Groei van bomen uit het tropisch regenwoud in relatie tot fosfor voorziening : zaalingen een verschillende regeneratiestrategie en hun aanpassingen aan een lage beschikbaarheid van fosfor in Guyana /

Raaimakers, Dorinne. January 1900 (has links)
Thesis (doctoral)--Universiteit Utrecht, 1995. / Vita. Includes bibliographical references (p. 89-94).
486

Regeneration and growth of several canopy tree species in the Maya Forest of Quintana Roo, Mexico : the role of competition and microhabitat conditions /

Sorensen, NaDene S. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 204-236). Also available on the World Wide Web.
487

Modelagem geoestatística em quatro formações florestais do Estado de São Paulo / Geostatistical modeling in four forest formations of Sao Paulo State

Melissa Oda-Souza 18 September 2009 (has links)
Em muitos estudos ecológicos a distribuição dos organismos vivos era considerada aleatória, uniforme ou orientada ao longo de um simples gradiente. Ao contrário disso, sabe-se que eles podem se apresentar agregados em manchas, em forma de gradientes ou em outros tipos de estruturas espaciais. Dessa forma, a descrição e incorporação da estrutura espacial para a compreensão dos fenômenos ecológicos tem se tornado cada vez mais necessária. Neste trabalho, foram discutidos aspectos relacionados à amostragem e à modelagem da estrutura de continuidade espacial, por meio da geoestatística baseada em modelo, em quatro formações florestais do Estado de São Paulo. Nas quatro formações florestais foram instaladas parcelas permanentes de 320 × 320 m e todos os indivíduos arbóreos no interior das parcelas com diâmetro maior ou igual a 5 cm foram mapeados, georreferenciados, medidos e identificados. Os modelos geoestatísticos ajustados mostraram que a percepção da estrutura de dependência espacial foi influenciada pelo tamanho e pela forma da unidade amostral. As parcelas quadradas de 20×20 m foram as que melhor descreveram a estrutura de continuidade espacial e as parcelas retangulares captaram a variabilidade da floresta. As quatro formações florestais avaliadas apresentaram estruturas espacias distintas, sendo que a Savana e Ombrófila apresentam estruturas espaciais mais pronunciadas do que as formações Estacional e Restinga. Por fim, ao comparar as estimativas geradas pela abordagem baseada em delineamento (teoria da amostragem clássica) e a abordagem baseada em modelo (geoestatística) por estudos de simulação, verificou-se que mesmo com dependência espacial os estimadores clássicos fornecem estimativas e intervalos de confiança igualmente válidos. / In many ecological studies the distribution of living organisms was considered random, uniform or oriented along a single gradient. Unlike this, it is known that they can present aggregated in patches, in the form of gradients or other types of spatial structures. Thus, the description and the incorporation of spatial structure for understanding of ecological phenomena is becoming increasingly necessary. In this work were discussed aspects related to sampling and modeling the structure of spatial continuity through model-based geostatistics on four forest formations of Sao Paulo State. In the four forest formations were installed permanent plots of 320 × 320 m. All individual trees within the plots with a diameter greater than or equal to 5 cm were mapped, georeferenced, measured and identified. The adjusted geostatistical models showed that the perception of spatial structure of dependence was influenced by the size and shape of sampling unit. The structure of spatial continuity was best described by square plots of 20 × 20 m. The rectangular plots capture the variability of the forest. The four forest formations evaluated showed distinct spatial structures. The Savanna and Dense Rain formations have spatial structures more pronounced than the Seasonal Semideciduos and Restinga formations. Finally, to compare the estimates generated by the design-based approach (classical sampling theory) and model-based approach (geostatistics) for simulation studies, was found that even with the spatial dependence, the classical estimators provide estimates and confidence intervals equally valid.
488

Environmental factors influencing ecotonal changes in an indigenous forest in the Keiskammahoek Forest Estate, Eastern Cape, South Africa

Kiva, Luthando January 2016 (has links)
This study investigates environmental factors influencing ecotonal changes in the Dontsa Forest Management Unit (FMU) of the Keiskammahoek Estate Forest which is located in the Amatole Mountains of the Eastern Cape in the Republic of South Africa. The patterns of forest edge movement were analysed to show trends of forest edge movement from 1975 to 1985, 1975 to 1992, 1975 to 2002, 1975 to 2014, 1985 to 1992, 1985 to 2002, 1985 to 2014, 1992 to 2002, 1992 to 2014 and 2002 to 2014 by digitizing and assessing the scale of forest edge movement using georeferenced aerial photographs. Belt transects were established in six sites that were selected on the basis of physiographic elements for determination of the driving forces of forest ecotonal changes. The results of the study show that the forest edge moved positive towards the grassland biome while in other sites there was contraction of the forest edge from 1975 to 2014. The findings of the study show that some forest patches moved with few individual pioneer species towards the grassland while indigenous species dominated in the ecotone area of the forest in other research sites. D whyteana, A latifolius, R melanophloes, A facultus, R prenoides, C aurea, C bispinosa, C inerme, and S martina are the plant species with high density in the forest ecotone while A latifolius, R prenoides, R melanophloes were highly distributed along the grassland area. The results also show that harvesting of Pinus patula and illegal harvesting of understory species are major factors that result in ecotonal changes of Dontsa FMU. The research sites adjacent to residential areas have experienced reduction of ecotone area as compared to the research sites in high altitude areas of the Amathole Mountains where there is less disturbance. The eastern facing aspect of the forest exhibited a high density of plants in the forest ecotone as compared to the west facing slope.
489

Optimising habitat creation for woodland birds : the relative importance of local vs landscape scales

Whytock, Robin C. January 2018 (has links)
Global land-use change and industrialisation has driven biodiversity declines and impaired ecosystem functioning. Recently, there have been large-scale efforts to not only halt habitat loss but create and restore habitat on formerly managed (e.g. agricultural) land. However, although the effects of habitat loss and fragmentation on biodiversity are well understood, our understanding of how biodiversity responds to habitat created in a patchy configuration is not. In particular, little is known about the relative importance of local (e.g. patch size) vs landscape scales (e.g. amount of habitat in the landscape) for restoring biodiversity in created habitat. Here, a long-term, large-scale natural experiment (the Woodland Creation and Ecological Networks project) was used to understand how bird species, communities and behaviour respond to woodland created in a patchy configuration on post-agricultural land. I used a combination of direct and indirect survey methods to quantify bird diversity, abundance and vocal behaviour in post-agricultural woodlands of known age in Great Britain. I show that secondary woodlands favour generalist species and older patches contain more individuals and species due to their vegetation structure. In relative terms, local-scale factors such as patch size made the greatest contribution to bird diversity and abundance. Colonisation events drive community assembly in new habitat, and I found that large-scale (km2) habitat patterns were more important than patch-level factors during colonisation of breeding territories by a long distance migrant bird (Willow Warbler Phylloscopus trochilus). Land management practices surrounding a habitat patch can also affect its perceived quality and relative attractiveness to potential colonisers. Using the Eurasian Wren Troglodytes troglodytes as a model species, I found that high proportions of agricultural land at woodland edges caused an increase in perceived predation risk. In conclusion, I suggest that post-agricultural woodlands rapidly provide valuable habitat for generalist woodland birds. Local, patch-level factors (area, vegetation structure) also appear relatively more important than landscape factors for woodland bird communities. Land-managers seeking to maximise the benefits of woodland creation for birds should thus focus on creating large patches with a diverse vegetation structure.
490

Dieta de aves em uma área de Mata Atlântica no sudeste do Brasil / Diet of birds in an area of ​​Atlantic forest in southeastern Brazil

Moreno, Daniele Janina 28 May 2014 (has links)
Submitted by Maria de Lourdes Mariano (lmariano@ufscar.br) on 2017-01-09T16:01:20Z No. of bitstreams: 1 MORENO_Daniele Janina_2015.pdf: 78237455 bytes, checksum: efa50b8a0ec9c0d58693a8b3ce61451b (MD5) / Approved for entry into archive by Maria de Lourdes Mariano (lmariano@ufscar.br) on 2017-01-09T16:01:34Z (GMT) No. of bitstreams: 1 MORENO_Daniele Janina_2015.pdf: 78237455 bytes, checksum: efa50b8a0ec9c0d58693a8b3ce61451b (MD5) / Approved for entry into archive by Maria de Lourdes Mariano (lmariano@ufscar.br) on 2017-01-09T16:01:42Z (GMT) No. of bitstreams: 1 MORENO_Daniele Janina_2015.pdf: 78237455 bytes, checksum: efa50b8a0ec9c0d58693a8b3ce61451b (MD5) / Made available in DSpace on 2017-01-09T16:01:50Z (GMT). No. of bitstreams: 1 MORENO_Daniele Janina_2015.pdf: 78237455 bytes, checksum: efa50b8a0ec9c0d58693a8b3ce61451b (MD5) Previous issue date: 2014-05-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Não informado pelo autor. / * / Não informado pelo autor

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