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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

An assessment of the trees of the Greening Soweto Tree Planting Project in Johannesburg, South Africa

Van Staden, Elizabeth Margaret 11 1900 (has links)
The Greening Soweto Tree Planting project in the City of Johannesburg, South Africa, was a greening initiative aimed at ensuring that benefits of the 2010 FIFA World Cup, presented that year in the country, extended beyond the event. In assessing the trees of this project, it was confirmed that the target number of trees consisting mainly of indigenous tree species were planted predominantly as street and park trees in previously disadvantaged areas, traditionally known to have the least trees in the city. The survival rate of the project is estimated to be 43.46%, implying inadequacies in tree planting and management of the project and necessitating guidelines with recommendations to improve tree planting practices in the city. Growth relationship equations for Olea europaea subsp. africana and Searsia lancea were developed and the growth parameter analysis reveals that all trees grow better in parks but C. africana trees should rather be planted on sidewalks than on medians, S. lancea trees should preferably be planted on medians and C. erythrophyllum may be planted on sidewalks or medians as they would grow well in both locations. It is estimated that this project contributed 30 390.11 tCO2 of standing carbon stocks valued at R3 646 812,87 or US$303,901.07 (assuming a CO2 price of US$10.00) in 2017 and could potentially contribute 387 170.93 tCO2 of sequestered carbon stocks valued at R46 460 511,82 or US$3,871,709.32 by 2031 as mitigation action against climate change. A positive connection impacting the growth of the trees has been identified between land use, land cover and maintenance, indicating that the best locations for trees are maintained parks and formal residential areas as well as paved areas where irrigation is provided. The presence of pests and diseases, conflict with overhead structures and roads and a lack of pruning negatively impacted the growth of the trees. Guidelines for new tree planting projects have been developed with recommendations to maintain the canopy cover percentage in the established urban forest, enhance tree planting in the previously disadvantaged regions, improve the survival rate of new tree planting projects and establish community engagement forums to inform future tree planting of the city. / Environmental Sciences / Ph. D. (Environmental Management)
32

Levantamento florístico quali-quantitativo da Praça do Relógio da Cidade Universitária "Armando de Salles Oliveira" - USP/São Paulo / Quali-quantitative floristic survey of the Relógio Square of Cidade Universitária "Armando de Salles Oliveira" - USP / São Paulo - Brazil.

Paiva, Giovanna Alves de 20 December 2006 (has links)
A Praça do Relógio da Cidade Universitária "Armando de Salles Oliveira" da Universidade de São Paulo (SP) é um exemplo de espaço livre planejado para cumprir funções ambientais e sociais. Com porte de verdadeiro parque urbano, 176 mil m2, conta com vegetação nativa originária de seis ecossistemas paulistas, compondo diversos núcleos cortados por caminhos que possiblitam a circulação dos usuários entre diversos pontos do Campus, além de alamedas de palmeiras e árvores ornamentais. O presente estudo ocupou-se de levantar, diagnosticar e analisar a vegetação da Praça do Relógio após nove anos de implantação do projeto de reurbanização. Para tanto, foi adotado o método de inventário do tipo censo, ou seja, a análise quali-quantitativa de todos os indivíduos arbóreos, arbustivos e palmeiras com mais de 0,20 m de altura. existentes na Praça do Relógio. Foram encontrados 3081 indivíduos, dos quais puderam ser identificados 3028, sendo pertencentes a 121 espécies, 93 gêneros e 52 famílias botânicas. Do total de indivíduos, 2316 são árvores (75,17%), 206 são arbustos (6,69%), 542 são palmeiras (17,59%) e apenas 17 são forrações (0,55%). Das 121 espécies identificadas, 21 (17,35%) são exóticas, o que demonstra uma grande preocupação com a utilização da flora nativa. Considerando-se toda a área, o estado geral da vegetação da praça pode ser considerado bom, pois 91,46% dos indivíduos foram considerados em bom estado, enquanto 1,36% foram considerados em ótimo estado, 3,33% em estado regular, 2,18% em péssimo estado e 1,42% encontravam-se mortos. Quanto à conformação estrutural da vegetação, 3,17% apresentavam desequilíbrio de caule e ou copa. Segundo observação 3,20% da vegetação apresentou algum problema fitossanitário, como a presença de pragas ou doenças. Apresentaram lesões no caule, 1,42% da população vegetal. Quanto às interações ecológicas, em 0,20% foram encontrados insetos úteis, em 0,07% foram encontrados ninhos de pássaros, 13,65% apresentaram líquens no caule, 0,26% apresentaram epífitas e 2,93% apresentaram fitoparasitas. Do total de indivíduos, apenas 9,07% encontrava-se em área pavimentada, porém mesmo estes apresentavam bom espaço para seu desenvolvimento. Espera-se que as informações geradas possam incentivar o uso da praça como área para estudo de ciências biológicas e educação ambiental, além de fornecer subsídios para sua manutenção, ressaltando a importância de espaços como este na qualidade do ambiente da cidade e na vida dos cidadãos. / The Relógio Square of Cidade Universitária " Armando de Salles Oliveira " of the University of São Paulo (SP) is an example of free space planned to carry out environmental and social functions. With an area of true urbane park, 176,000 m 2, disposes of native vegetation original from six ecosystems of São Paulo, composing several nucleuses cut by ways that turns possible the circulation of the users between several points of the Campus, besides avenues of palms trees and ornamental trees. The present study was occupied of standing up, diagnosing and analyzing the vegetation of the Relógio Square after nine years of introduction of the project of reurbanization. In that way, was adopted the method of inventory of the type census, in other words, the quali-quantitative analysis of all the arboreal individuals, shrubs and palms trees with more than 0.20 meters of height. existent in the Relógio Square. Were found 3,081 individuals, of which 3,028 could be identified, being pertaining to 121 species, 93 genus and 52 botanical families. Of the total of individuals, 2,316 are trees (75.17 %), 206 are shrubs (6.69 %), 542 are palms trees (17.59 %) and 17 are creeping plants (0.55 %). Of 121 identified species, only 21 (17.35 %) are exotic, which demonstrates a great preoccupation with the use of the Brazilian native flora. Considering the whole area, the general state of the vegetation of the square can be considered good, so 91.46 % of the individuals was considered in good condition, while 1.36 % was considered in the best state, 3.33 % in regular state, 2.18 % in the worst state and 1.42 % was dead. As for the structural resignation of the vegetation, 3.17 % was presenting imbalance of stem and or top. According to observation 3.20 % of the vegetation presented some phytosanitary problem, like the presence of nuisances or diseases. They presented injuries in the stem, 1.42 % of the vegetable population. As for the ecological interactions, in 0.20 % useful insects were found, in 0.07 % nests of birds were found, 13.65 % presented lichens in the stem, 0.26 % presented epiphytes and 2.93 % presented phytoparasits. Of the total of individuals, only 9.07 % was in paved area, however even these were presenting good space for his development. It is waited that the produced information could stimulate the use of this square like area for study of biological sciences and environmental education, besides supplying subsidies for his maintenance, emphasizing the importance of spaces like this one in the capacity of the environment of the city and in the life of the citizens.
33

Arborização urbana de quatro cidades do leste de Mato Grosso do Sul / Urban tree of four cities of eastern Mato Grosso do Sul

Silva, Michelly Cristina da 12 March 2013 (has links)
Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-09-23T17:10:47Z No. of bitstreams: 2 Dissertação_Michelly-1.pdf: 1003558 bytes, checksum: f7289e1224355e7fb4cda6571653c74c (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-09-23T18:33:16Z (GMT) No. of bitstreams: 2 Dissertação_Michelly-1.pdf: 1003558 bytes, checksum: f7289e1224355e7fb4cda6571653c74c (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-09-23T18:33:16Z (GMT). No. of bitstreams: 2 Dissertação_Michelly-1.pdf: 1003558 bytes, checksum: f7289e1224355e7fb4cda6571653c74c (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-03-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In order to evaluate the quality and quantity of tree species planted in the cities of MS: Cassilândia (CA) and Paranaíba (PA), with the lowest PIB; Chapadão South (CH) and Costa Rica (CO), with higher PIB a survey of tree species present in 30 blocks of each of these cities was done. Trees were identified and recorded information such as: plant health; planting site; pruning; trees under power lines, tree size, position on the sidewalk; origin; outer root condition and existence of sidewalks. Shannon’s diversity index and Pielou’s evenness index was calculated. To analyze the structural and floristic similarity, the Jaccard and Morisita’s indexes was employed. Found 3180 individuals belonging to 100 species of 40 families, with CA, CH, CO and PA had 838, 1130, 657 and 555 individuals respectively. Shannon’s index was 2.08 overall. Jaccard’s index was 45%, cities with higher PIB and a lower PIB were more similar to each other. Morisita’s similarity index showed structural similarity between cities, ranging between 0.82 and 0.99. About the position on the sidewalk, the cities with the highest PIB had a number of trees above and below expectations at the curb and center, respectively. Otherwise, cities with the lowest PIB showed opposite results. By ANOVA test, CA, CH and PA were different, CH showed an average number of trees significantly larger and PA, a smaller number. The cities with the highest PIB had a number of trees higher than expected for individuals without any conflict with sidewalks and below expectations for those who had some type of conflict. Already the cities with the lowest PIB showed opposite results. About the origin, the cities with the highest PIB had a number of exotic individuals above the expected, native from Brazil less than expected, since the native Cerrado had a higher number than expected. The cities with the lowest PIB showed opposite results. The most abundant species throughout the survey was Licania tomentosa (oiti), totaling 1879 individuals (59%), representing in CA, CH, CO and PA, 85%, 36%, 57% and 66% respectively. Exotic species totaled 68%, while 22% are native from Brazil and 4% are Cerrado’s native. Among the 3180 individuals found: 80% were planted in front of homes, 14% in other places, such as churches, schools, kindergartens, clinics, and other 6% in front of business establishment. Concerning the plant health, 81% of the total were in good condition, 17% in satisfactory condition, and 2% in poor condition, 44% are free and 56% are under the power lines, of which 10% had conflict. As for pruning, 75.4% of sampled trees exhibited correct pruning, 9.5% incorrect, 12% nonexistent and 2.6% radical. The cities with the highest PIB showed greater wealth than those with lower PIB, and greater arboreal suitability in various aspects. Moreover, there is excessive use of exotic species and not appropriate species, due the large size. / Com o objetivo de avaliar comparativamente a qualidade e quantidade das espécies arbóreas plantadas nos municípios de Mato Grosso do Sul (MS): Cassilândia (CA) e Paranaíba (PA), com menor Produto Interno Bruto (PIB); Chapadão do Sul (CH) e Costa Rica (CO), com maior PIB, foi realizado um levantamento das espécies arbóreas presentes em 30 quadras de cada cidade. Os indivíduos arbóreos foram identificados e registradas informações como: fitossanidade; local do plantio; poda; árvores sob rede elétrica; porte arbóreo; posição na calçada; origem; condição externa da raiz e existência de calçamento. Foram calculados o índice de diversidade Shannon e o índice de equabilidade de Pielou. Para analisar a similaridade florística e estrutural, foram empregados os índices de Jaccard e de Morisita. Foram encontrados 3180 indivíduos, pertencentes a 100 espécies de 40 famílias, sendo que CA, CH, CO e PA apresentaram, respectivamente, 838, 1130, 657 e 555 indivíduos. O índice de Shannon total foi de 2,08. O índice de Jaccard foi de 45%; as cidades com maior PIB e as com menor PIB foram mais semelhantes entre si. O índice de similaridade de Morisita mostrou similaridade estrutural entre as cidades, variando entre 0,82 e 0,99. As cidades com maior PIB tiveram um número de árvores acima e abaixo do esperado no meio-fio e no centro da calçada, respectivamente. Já as cidades com menor PIB mostraram resultados opostos. Pelo teste de ANOVA, CA, CH e PA foram diferentes entre si; CH apresentou um número médio de árvores significativamente maior e PA, um número menor. As cidades com maior PIB tiveram um número de árvores acima do esperado para os indivíduos sem nenhum tipo de conflito com as calçadas e abaixo do esperado para aqueles que apresentaram conflito. Já as cidades com menor PIB mostraram resultados opostos. Com relação à origem, as cidades com maior PIB tiveram um número de indivíduos exóticos acima do esperado, nativas do Brasil menor que o esperado; já as nativas do Cerrado tiveram um número maior que o esperado. As cidades com menor PIB mostraram resultados contrários. A espécie mais abundante foi Licania tomentosa (oiti), totalizando 1879 indivíduos (59%), representando em CA, CH, CO e PA, 85%, 36%, 57% e 66%, respectivamente. Espécies exóticas totalizaram 68%, enquanto 22% são nativas do Brasil e 4% são nativas do cerrado. Dos 3180 indivíduos encontrados: 80% foram plantadas em frente às residências, 14% em outros locais, como igrejas, escolas, creches, consultórios, entre outros e 6% em frente a estabelecimentos comerciais. Quanto à fitossanidade, 81% do total encontravam-se em boas condições, 17% em condições satisfatórias e 2% em condições ruins; 44% encontram-se livre e 56% estão sob a fiação elétrica, dos quais 10% apresentaram conflito. Quanto à poda, 75,4% das árvores amostradas apresentaram poda correta, 9,5% incorreta, 12% inexistente e 2,6% radical. As cidades com maior PIB apresentaram maior riqueza do que as com menor PIB, e uma maior adequação em vários aspectos. Além disso, há um uso excessivo de espécies exóticas e espécies não apropriadas, em virtude do porte elevado.
34

Tree planting and air quality in Hong Kong urban areas

Tong, Mei-ka, Julie., 湯美嘉. January 2005 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
35

The development of a wall-less plug for planting stock of forest trees.

Schuermans, Jean. 14 November 2013 (has links)
High output commercial nurseries that cater for the forestry industry are continuously challenged to efficiently and cost effectively produce good quality planting stock to establish large plantations. Currently, South African commercial nurseries produce planting stock in solid compartmentalized trays. One of the major drawbacks of these containers is the susceptibility of trees to root deformation following outplanting, combined with the need for the return of empty containers to the nursery. A potential solution to these challenges is the introduction of wall-less plugs for the production of planting stock. Wall-less plugs are volumes of growing medium, usually cylindrical in shape, devoid of an impenetrable wall in which a plant can grow and establish itself. Such plugs may enable the production of planting stock with improved root systems, without the need for the return of empty containers after outplanting. In this research four prototypes of wall-less plugs were developed, produced on a small scale and tested. These were: 1) Paper-maché plugs made using the original WRIBLOK protocol whereby composted pine bark was bound together with repulped newspaper, 2) Sponge blocks, 3) Hessian bags and 4) Covetan bags. The performance of these prototype wall-less plugs was compared with the performance of four tray types used commercially by the forestry industry: 1) Poly 128 shallow, 2) Poly 98 deep, 3) Unigro 128 and 4) Sappi 49. These are polystyrene and polypropylene-based containers. Of these containers the Unigro 128 and Sappi 49 containers were of similar performance. Performance in terms of height and root collar diameter increase over ten weeks from the time of sowing of the paper-maché plugs was similar to that of the Unigro and Sappi 49 containers. The sponge block, Hessian bags and Covetan bags produced inferior quality planting stock compared to the other treatments tested. Although little progress was made in the ability to describe how one root system differs from another in terms of their branching patterns, a technique was developed to determine root surface area by image analysis software that is freely available. This method may prove useful for further research and for determining seedling quality in commercial nurseries. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.
36

Participation and pressure in the Mist Kingdom of Sumba : a local NGO's approach to tree-planting / by Justin Lee.

Lee, Justin Lance January 1995 (has links)
Errata pasted on front end papers. / Bibliography: leaves 356-371. / xxii, 371 leaves : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geography, 1996?
37

Ecological impacts of biodiversity enrichment in oil palm plantations

Teuscher, Miriam 27 November 2015 (has links)
No description available.
38

Levantamento florístico quali-quantitativo da Praça do Relógio da Cidade Universitária "Armando de Salles Oliveira" - USP/São Paulo / Quali-quantitative floristic survey of the Relógio Square of Cidade Universitária "Armando de Salles Oliveira" - USP / São Paulo - Brazil.

Giovanna Alves de Paiva 20 December 2006 (has links)
A Praça do Relógio da Cidade Universitária "Armando de Salles Oliveira" da Universidade de São Paulo (SP) é um exemplo de espaço livre planejado para cumprir funções ambientais e sociais. Com porte de verdadeiro parque urbano, 176 mil m2, conta com vegetação nativa originária de seis ecossistemas paulistas, compondo diversos núcleos cortados por caminhos que possiblitam a circulação dos usuários entre diversos pontos do Campus, além de alamedas de palmeiras e árvores ornamentais. O presente estudo ocupou-se de levantar, diagnosticar e analisar a vegetação da Praça do Relógio após nove anos de implantação do projeto de reurbanização. Para tanto, foi adotado o método de inventário do tipo censo, ou seja, a análise quali-quantitativa de todos os indivíduos arbóreos, arbustivos e palmeiras com mais de 0,20 m de altura. existentes na Praça do Relógio. Foram encontrados 3081 indivíduos, dos quais puderam ser identificados 3028, sendo pertencentes a 121 espécies, 93 gêneros e 52 famílias botânicas. Do total de indivíduos, 2316 são árvores (75,17%), 206 são arbustos (6,69%), 542 são palmeiras (17,59%) e apenas 17 são forrações (0,55%). Das 121 espécies identificadas, 21 (17,35%) são exóticas, o que demonstra uma grande preocupação com a utilização da flora nativa. Considerando-se toda a área, o estado geral da vegetação da praça pode ser considerado bom, pois 91,46% dos indivíduos foram considerados em bom estado, enquanto 1,36% foram considerados em ótimo estado, 3,33% em estado regular, 2,18% em péssimo estado e 1,42% encontravam-se mortos. Quanto à conformação estrutural da vegetação, 3,17% apresentavam desequilíbrio de caule e ou copa. Segundo observação 3,20% da vegetação apresentou algum problema fitossanitário, como a presença de pragas ou doenças. Apresentaram lesões no caule, 1,42% da população vegetal. Quanto às interações ecológicas, em 0,20% foram encontrados insetos úteis, em 0,07% foram encontrados ninhos de pássaros, 13,65% apresentaram líquens no caule, 0,26% apresentaram epífitas e 2,93% apresentaram fitoparasitas. Do total de indivíduos, apenas 9,07% encontrava-se em área pavimentada, porém mesmo estes apresentavam bom espaço para seu desenvolvimento. Espera-se que as informações geradas possam incentivar o uso da praça como área para estudo de ciências biológicas e educação ambiental, além de fornecer subsídios para sua manutenção, ressaltando a importância de espaços como este na qualidade do ambiente da cidade e na vida dos cidadãos. / The Relógio Square of Cidade Universitária " Armando de Salles Oliveira " of the University of São Paulo (SP) is an example of free space planned to carry out environmental and social functions. With an area of true urbane park, 176,000 m 2, disposes of native vegetation original from six ecosystems of São Paulo, composing several nucleuses cut by ways that turns possible the circulation of the users between several points of the Campus, besides avenues of palms trees and ornamental trees. The present study was occupied of standing up, diagnosing and analyzing the vegetation of the Relógio Square after nine years of introduction of the project of reurbanization. In that way, was adopted the method of inventory of the type census, in other words, the quali-quantitative analysis of all the arboreal individuals, shrubs and palms trees with more than 0.20 meters of height. existent in the Relógio Square. Were found 3,081 individuals, of which 3,028 could be identified, being pertaining to 121 species, 93 genus and 52 botanical families. Of the total of individuals, 2,316 are trees (75.17 %), 206 are shrubs (6.69 %), 542 are palms trees (17.59 %) and 17 are creeping plants (0.55 %). Of 121 identified species, only 21 (17.35 %) are exotic, which demonstrates a great preoccupation with the use of the Brazilian native flora. Considering the whole area, the general state of the vegetation of the square can be considered good, so 91.46 % of the individuals was considered in good condition, while 1.36 % was considered in the best state, 3.33 % in regular state, 2.18 % in the worst state and 1.42 % was dead. As for the structural resignation of the vegetation, 3.17 % was presenting imbalance of stem and or top. According to observation 3.20 % of the vegetation presented some phytosanitary problem, like the presence of nuisances or diseases. They presented injuries in the stem, 1.42 % of the vegetable population. As for the ecological interactions, in 0.20 % useful insects were found, in 0.07 % nests of birds were found, 13.65 % presented lichens in the stem, 0.26 % presented epiphytes and 2.93 % presented phytoparasits. Of the total of individuals, only 9.07 % was in paved area, however even these were presenting good space for his development. It is waited that the produced information could stimulate the use of this square like area for study of biological sciences and environmental education, besides supplying subsidies for his maintenance, emphasizing the importance of spaces like this one in the capacity of the environment of the city and in the life of the citizens.
39

The financial feasibility of tree-planting under agroforestry: a case study from the Groundnut Basin of Senegal

Diallo, Alioune January 1992 (has links)
Agroforestry is a new term for an old practice of resource management which includes the planting of trees and agricultural crops on the same piece of land, either simultaneously or sequentially. In Senegal, this new approach has been praised, mainly because it came along at a time when private participation in reforestation was badly needed. Since the early 1980s, the Snegalese government has been devoting money and personnel to the implementation of agroforestry projects, particularly in the Groundnut Basin. In spite of these efforts, small private farmers response to the suggested agroforestry systems has been slow in most parts of the region. Assuming that financial return is the most viable mean for triggering large-scale adoption of agroforestry by private farmers, this study analyzes the financial attractiveness of the three agroforestry systems promoted in the Groundnut Basin, and compares them to the base case of growing groundnuts alone. The three agroforestry systems are: kad and millet, cashew and groundnuts, and a Eucalyptus block plantation. For each system, costs and benefits accruing to the farmer are identified and estimated. The financial attractiveness of each system is measured using two criteria: present net worth (PNW) and internal rate of return (IRR). Using the criterion that a system with a PNW greater than zero is acceptable, the results indicate that all three agroforestry systems are acceptable at 10 and 15 percent discount rates. The kad and millet system is acceptable at rates nearing 50 percent. This is due mainly to the valuation of the crop loss avoided in the presence of kad trees. When this component was not internalized, the IRR was found at only 15.8 percent. The cashew and groundnut system has the next highest IRR at 25.6 percent, followed by The Eucalyptus block plantation at 18.8 percent. The base case yields negative PNW at all three discount rates, and an IRR equal to 4. 7 percent. This low return from the groundnut enterprise may be due to the valuation of family labor which does not generally constitute an out-of-pocket cost. Some environmental benefits attributable to agroforestry systems and some socio-economic constraints that may be part of the farmers' reluctance to adopt the new systems are discussed. Finally, some recommendations are made to help improve the current approach to private involvement in reforestation. It is suggested that, in order to anticipate the loss in interest that follows most incentive programs once the incentives stop, the "cost sharing" program and other financial incentive programs should be limited to systems, which have strong favorable impacts on the environment but do not afford sufficient financial rewards by themselves for wide scale adoption. / M.S.
40

Experimental biodiversity enrichment in an oil-palm plantation

Gérard, Anne 15 November 2016 (has links)
Die großflächige Umwandlung von tropischen Wäldern hat zu dramatischen Verlusten von Biodiversität und assoziierten Ökosystemdienstleistungen und –funktionen geführt. Indonesien ist ein besonders schwerwiegendes Beispiel für den Verlust von Waldflächen und Biodiversität. Landumnutzungen, in starkem Maße durch den Anbau von Ölpalmen vorangetrieben, stellen eine erhebliche Bedrohung für die außergewöhnlich hohe Biodiversität des Landes dar. Landwirtschaftssysteme, wie Agroforstsysteme, können hingegen genutzt werden, um die Biodiversität und Ökosystemfunktionen in von Ölpalmen dominierten Landschaften zu erhöhen. In Regionen, in denen Ölpalmplantagen bereits die Landschaft dominieren, kann diese Erhöhung nur durch systematische Renaturierung erfolgen. Die zugrunde liegenden ökologischen und soziökonomischen Prozesse und damit verbundene Beschränkungen und Kompromisse von Renaturierungsmaßnahmen in von Ölpalmen dominierten Landschaften sind jedoch weitgehend unbekannt. Um diese Wissenslücke zu schließen, habe ich mit Kollegen aus Deutschland und Indonesien ein Langzeitexperiment zur Erhöhung der Biodiversität aufgebaut. Wir haben experimentell Bäume in Form von „Inseln“ in eine konventionelle Ölpalmplantage gepflanzt und hierbei systematisch die Flächengröße, das Diversitätslevel und die Artzusammensetzung variiert. Wir haben hierfür sechs multifunktionale heimische Baumarten ausgewählt. Auf der Fläche der Bauminseln haben wir einen Teil der Ölpalmen gefällt, um die Lichtverfügbarkeit für die gepflanzten Bäume durch eine reduzierte Ölpalmdichte zu erhöhen. In dieser Doktorarbeit stelle ich den Aufbau des Experiments vor und gebe einen breiten Einblick in anfängliche Auswirkungen des Experiments, indem ich ökologische Aspekte in Betracht ziehe, sowie Veränderungen hinsichtlich des Ernteertrags. Da die Zeit kurz nach der Pflanzung ein Nadelöhr für die Langzeitetablierung der Bäume darstellt, ist sie sehr kritisch, um die erwünschten Renaturierungserfolge in der Zukunft zu erzielen. Des Weiteren kann die Anfangszeit auch aus der Sicht der Landwirte eine entscheidende Hürde darstellen, da der Nutzen der Bauminseln erst lange Zeit nach ihrer Pflanzung entsteht. Zuerst beschreibe ich Umweltvariablen und biotische Charakteristika der den experimentellen Flächen assoziierten Vegetation, Invertebraten und Vögel vor der Errichtung des Experiments, sowie anfängliche Auswirkungen des Experiments auf die Fauna. Ein Jahr nach der Errichtung des Experiments hatten die Baumpflanzungen einen insgesamt positiven Effekt auf die Artengemeinschaften von Vögeln und Invertebraten in der Plantage. Die Größe der Bauminseln wirkte sich lediglich auf die Diversität und Abundanz von Invertebraten positiv aus, die somit auf kleinskalige Veränderungen reagierten. Ausgehend von diesen Ergebnissen erwarte ich einen weiteren Anstieg der Biodiversität und Ökosystemfunktionen in der Zukunft. Danach berichte ich über den Anwuchserfolg der Bäume und ermittle die wichtigsten Determinanten für den Wuchs und das Überleben der Bäume. Insgesamt sind die Bäume gut angewachsen, jedoch gab es große Unterschiede zwischen den Baumarten hinsichtlich relativer Höhenwachstums-, Dickenwachstums- sowie Überlebensraten. Arten mit hohen Wachstumsraten wiesen vorwiegend auch hohe Überlebensraten auf. Auf Versuchsflächenebene hatten Standortbedingungen, Flächengröße und Diversitätslevel der gepflanzten Bäume lediglich einen geringen Einfluss auf das mittlere Baumwachstum und die Überlebensrate. Auf Individuenebene habe ich signifikante Nachbarschaftseffekte festgestellt. Hohe benachbarte Bäume und die Distanz zu verbleibenden Ölpalmen begünstigten die Entwicklung der Bäume. Noch ist es zu früh zu entscheiden, welche der Baumarten sich generell am besten eignen, um Renaturierungsziele zu erreichen. Unterschiede in der anfänglichen Entwicklung liefern jedoch wichtige Informationen für eine zukünftige Bewertung der Arten. Zuletzt präsentiere ich Auswirkungen des Experiments auf den Ölpalmertrag. Nach zwei Jahren waren die Erträge pro Ölpalmindividuum erhöht, sowohl auf als auch direkt neben den Versuchsflächen. Die geschätzten Ertragsänderungen für die verschiedenen Flächengrößen unter Einbezug von Ernteverlusten durch gefällte Ölpalmen sowie Effekte auf benachbarte Ölpalmen deuten darauf hin, dass die erhöhten Ernteerträge insbesondere in großen Bauminseln mindestens das Fällen von Ölpalmen kompensiert haben. Diese Ergebnisse, die in der frühen Phase der Bauminseletablierung erzielt wurden, sind vielversprechend für die Erarbeitung nachhaltiger Managementoptionen für Ölpalmplantagen, die ökologische und ökonomische Funktionen in Einklang bringen. Die anfänglichen Auswirkungen waren stärker und insbesondere aus ökonomischer Perspektive profitabler als ich erwartet habe. Die Nachbarschaftseffekte und die Auswirkungen der experimentell veränderten Variablen waren bislang jedoch überwiegend schwach. Ich erwarte, dass diese Auswirkungen mit der Zeit stärker ausgeprägt sein werden. Durch Erkenntnisse, die aus zukünftigen Langzeitbeobachtungen des Experiments, das ich in dieser Doktorarbeit vorstelle, gewonnen werden, können Wissenslücken geschlossen werden. Somit kann die Ausarbeitung von Managementrichlinien für von Ölpalmen dominierten Landschaften ermöglicht werden, die sowohl ökologisch verbessert als auch ökonomisch lohnenswert sind. Diese Doktorarbeit stellt einen wesentlichen Beitrag zur generellen Beurteilung des Experiments dar, wodurch darüber hinaus auch neue Erkenntnisse für die Renaturierungswissenschaft gewonnen werden können.

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