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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.
151

The evaluation of various reseeding methods for restoring old croplands in the Highveld region of South Africa

Van Oudtshoorn, Frits 30 November 2007 (has links)
In spite of the relative simple vegetation structure, the Grassland biome has surprisingly high species diversity. The Grassland biome is also the most transformed biome in South Africa, with cultivation having the largest impact. When croplands are abandoned, secondary succession leads to low diversity Hyparrhenia hirta dominated grassland. A combination of two seed mixtures, two seeding densities and two establishment methods was established in plots on a recently abandoned cropland at Suikerbosrand Nature Reserve to evaluate their effect on secondary succession. The rip plots, where more resources were available between the rip lines, have shown higher densities of relic weeds as well as local perennials, showing some progressive successional movement. However, Hyparrhenia hirta was one of the non-sown perennials increasing in the rip plots. Hyparrhenia invasion and relic weeds were best controlled in the plough plots. Although Hyparrhenia was successfully controlled in plough plots, no secondary succession occurred in these treatments. / Agriculture, Animal Health and Human Ecology / M. Tech. (Nature Conservation)
152

Rôle des infrastructures portuaires dans le maintien des populations de poissons côtiers : apports de la restauration écologique / Role of ports in the renewal of coastal fish populations : contribution of ecological restoration

Mercader, Manon 26 April 2018 (has links)
La perte d'habitat engendrée par l'artificialisation des côtes a de graves conséquences sur la biodiversité marine. Aussi, dans une optique de maintien de la biodiversité et des stocks de poissons, il peut s’avérer intéressant de restaurer certaines fonctions écologiques dans les zones anthropisées. Cette thèse avait pour objectif d’estimer le rôle potentiel des ports en tant qu’habitat pour les juvéniles de poissons côtiers et d’évaluer dans quelle mesure ce rôle peut être amélioré par le biais d’actions de restauration. Des expérimentations en aquarium ont permis d’estimer que le taux de survie des juvéniles sur des habitats artificiels utilisés à des fins de restauration était comparable à celui observé sur des roches. Une étude de la distribution spatiale des juvéniles à l’échelle d’un paysage sous-marin a ensuite montré que les ports pouvaient abriter des densités en juvéniles représentant de 50 à 90 % de celles retrouvées en milieu naturel. Les densités à l'intérieur des ports étaient cependant tributaires du type d’habitat considéré; les quais sans complexité structurale abritant les densités les plus faibles. Enfin, l'étude de cas concrets, a montré que la réhabilitation des ports pouvait significativement augmenter les densités de juvéniles à l’échelle de l’habitat, celles-ci pouvant atteindre des niveaux comparables au milieu naturel. Toutefois, ces bénéfices restaient faibles à l’échelle d’un port dans sa globalité. Ces travaux suggèrent un réel potentiel des infrastructures portuaires en tant qu’habitat juvénile alternatif, en particulier si des actions de restauration y sont entreprises. Cependant, pour plus d’efficacité, les projets de restauration devraient être menés à large échelle et utiliser une diversité d’habitats artificiels. La restauration écologique des ports peut ainsi être employée comme un outil complémentaire aux mesures de protection dans le cadre d’une gestion intégrée des zones côtières à l’échelle du paysage. / Habitat loss caused by urban sprawl has harmful consequences on marine biodiversity. With a view to maintaining biodiversity and fish stocks, it may be worthwhile to restore some ecological features in anthropized areas. The aim of this thesis was to estimate the potential role of ports as habitat for juvenile coastal fish and to evaluate how this role can be improvedthrough restoration actions. Tank experiments revealed that juvenile survival rate on artificial habitats used for restoration purpose could be equivalent to that observed on natural habitat. The assessment of the spatial distribution of juvenile at the scale of a seascape permitted to estimate that harbors could host densities of juvenile that were between 50 to 90% of thoseobserved in natural sites. Within harbors densities were highly dependent on the type of habitat, featureless dock hosting the lowest densities. Subsequently, based on case studies, this work demonstrated that harbors rehabilitation could significantly enhance juvenile densities at the habitat scale. Densities on restored habitat might reach those observed in natural habitats.However, at the scale of the whole harbor benefits were low. This work suggests that harbors have a real potential as an alternative juvenile habitat, especially if restoration actions are undergone. However, for more efficiency, restoration projects should be led at the scale of the whole site and include a diversity of artificial habitats. Thereby, restoration approaches shouldbe considered as a complementary tool to protection measures in a seascape integrated management approach of coastal areas
153

Research and development of a preliminary South African voluntary carbon standard for landscape restoration projects

Curran, Patrick January 2012 (has links)
The mandatory and voluntary carbon markets have both developed around the increasing trade of carbon offsets. In order to add legitimacy to an otherwise intangible commodity there has been a rise in the development of third party carbon certification standards, particularly in the voluntary market. These standards aim to provide independent, third party certification to projects that are developed specifically to generate and sell carbon offsets. South Africa has the opportunity to engage with these markets, but current participation in and certification of projects is sluggish. These projects have not taken off mainly due to the high transaction costs and lag times surrounding the current certification of projects', complex baseline methodologies, accounting uncertainty and the often bureaucratic systems surrounding the current voluntary carbon certification standards and methodologies. In order to overcome these pitfalls this project aimed to address these challenges through initiating the development of a preliminary South African voluntary carbon standard. This was done by: a) undertaking a critical assessment of the development of current carbon markets, with a particular focus on voluntary markets and third party certification, b) critically analysing the current voluntary carbon certification standards for best practices, pitfalls and weaknesses. To provide a better understanding of the historical development of voluntary certification standards, various established certification standards were evaluated, including the Forestry Stewardship Council (FSC), Marine Stewardship Council (MSC) and ISO 14000 standards. This analysis focussed on the challenges they faced in acceptance and in particular how they have managed to operationalize sustainable development within the certification process. In order to explicitly ensure the incorporation of a sustainable development assessment of projects under the proposed standard, an expert workshop was held with 14 experts from a wide variety of disciplines. These experts identified the crucial sustainable development challenges facing South Africa. They identified 12 sub-themes and 44 indicators that could be used to measure and incorporate sustainable development indicators into the certification process. These were then further developed through using the 'Input – Output – Outcome – Impact' framework model which allowed the indicators to be organised and understood and thus practical. The analysis of the voluntary certification standards and the development of the sustainable development indicator framework were ultimately incorporated into the development of the proposed South African voluntary carbon standard. The key approach to this standard is the incorporation and focus of the proposed standard to ensuring the generation of net SD benefits and placing them at the same level as carbon within the project design and development, validation and verification process. The full and effective integration of these has been missing within current fully fledged voluntary carbon standards, as they often rely on a mixture of project design standards to achieve this. Offering the inclusion of all components into one standard, specifically designed for South Africa, will not only assure SD credentials but also increase transparency and understanding, and reduce costs. This thesis allowed for the development of innovative new ideas and process focussed specifically at including and mainstreaming South Africa’s developmental challenges into the certification process. This is the hoped that the standard will effectively certify South African based landscape restoration projects, but also decrease costs and increase efficiencies in order to encourage the development of these projects. This preliminary standard not only aims to incorporate and address all the issues identified but also has the end goal of acting as the basis for future debate and development surrounding a potential South African voluntary carbon certification standard.
154

Rates of Lateral Expansion of Biological Soil Crusts

January 2017 (has links)
abstract: Biological soil crusts (biocrust) are photosynthetic communities of organisms forming in the top millimeters of unvegetated soil. Because soil crusts contribute several ecosystem services to the areas they inhabit, their loss under anthropogenic pressure has negative ecological consequences. There is a considerable interest in developing technologies for biocrust restoration such as biocrust nurseries to grow viable inoculum and the optimization of techniques for field deployment of this inoculum. For the latter, knowledge of the natural rates of biocrust dispersal is needed. Lateral dispersal can be based on self-propelled motility by component microbes, or on passive transport through propagule entrainment in runoff water or wind currents, all of which remain to be assessed. I focused my research on determining the capacity of biocrust for lateral self-propelled dispersal. Over the course of one year, I set up two greenhouse experiments where sterile soil substrates were inoculated with biocrusts and where the lateral advancement of biocrust and their cyanobacteria was monitored using time-course photography, discrete determination of soil chlorophyll a concentration, and microscopic observations. Appropriate uninoculated controls were also set up and monitored. These experiments confirm that cyanobacterial biological soil crusts are capable of laterally expanding when provided with presumably optimal watering regime similar to field conditions and moderate temperatures. The maximum temperatures of Sonoran Desert summer (up to 42 °C), exacerbated in the greenhouse setting (48 °C), caused a loss of biomass and the cessation of lateral dispersal, which resumed as temperature decreased. In 8 independent experiments, biocrust communities advanced laterally at an average rate of 2 cm per month, which is half the maximal rate possible based on the instantaneous speed of gliding motility of the cyanobacterium Microcoleus vaginatus. In a span of three months, populations of M. vaginatus, M. steenstrupii, and Scytonema spp. advanced 1 cm/month on average. The advancing crust front was found to be preferentially composed of hormogonia (differentiated, fast-gliding propagules of cyanobacteria). Having established the potential for laterally self-propelled community dispersal (without wind or runoff contributions) will help inform restoration efforts by proposing minimal inoculum size and optimal distance between inoculum patches. / Dissertation/Thesis / Masters Thesis Biology 2017
155

Inclusão de parâmetros hidrológicos na avaliação da restauração florestal / Inclusion of hydrological parameters in the evaluation of forest restoration

Bessi, Débora 14 February 2017 (has links)
Submitted by Milena Rubi ( ri.bso@ufscar.br) on 2017-11-07T18:33:20Z No. of bitstreams: 1 BESSI_Debora_2017.pdf: 1353522 bytes, checksum: 5ad9f952fd09c66175d21192226aa1e4 (MD5) / Approved for entry into archive by Milena Rubi ( ri.bso@ufscar.br) on 2017-11-07T18:33:35Z (GMT) No. of bitstreams: 1 BESSI_Debora_2017.pdf: 1353522 bytes, checksum: 5ad9f952fd09c66175d21192226aa1e4 (MD5) / Approved for entry into archive by Milena Rubi ( ri.bso@ufscar.br) on 2017-11-07T18:33:44Z (GMT) No. of bitstreams: 1 BESSI_Debora_2017.pdf: 1353522 bytes, checksum: 5ad9f952fd09c66175d21192226aa1e4 (MD5) / Made available in DSpace on 2017-11-07T18:34:06Z (GMT). No. of bitstreams: 1 BESSI_Debora_2017.pdf: 1353522 bytes, checksum: 5ad9f952fd09c66175d21192226aa1e4 (MD5) Previous issue date: 2017-02-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / The presence of vegetation cover plays a regulatory role in the water balance through the capture and distribution of rainwater within the compartments of the ecosystem, aiding in the regulation of water flow through the soil, as well as in the process of water supply for the recharge of water bodies. It is possible to say that areas with absence of vegetation and in state of degradation do not present the same effects. Due to the complexity of the biological interactions with the abiotic factors of the environment, the current focus of the environmental recovery is almost exclusive in the biological component, not knowing at what point during the vegetation development, the restoration contributes to the water maintenance, or In what moment and how it will interfere in the water balance of a hydrographic microbasin. The objective of this work was to characterize the behavior of hydrological parameters in forest areas at different stages of restoration by conducting the natural regeneration in order to insert them as a tool to evaluate the restoration. For this purpose, a microbasin was selected within the. (SPP), where three plots of 400 m 2 were demarcated for each treatment, two treatments with different ages of succession (Treatment 1 - 4 years , And Treatment 2 - 10 years) and a fragment without human interference (Treatment 3 - 43 years). The research characterized and evaluated the conditions of natural regeneration through vegetation structure indicators: tree height, trunk diameter, and soil: soil cover by grass and litter, resistance to soil compaction, humidity and Infiltration rate; And luminosity, in addition to the application of diversity and wealth indexes. In each plot, 12 rain gauges were installed and flow through the trunk in all the trees with CAP> 15cm in order to characterize the distribution of the rainfall in the three taratamentos through the hydrological indicators: open precipitation, effective precipitation, internal precipitation, flow through the trunk and interception. The results on vegetation diversity and structure indicated an increasing trend in both number and richness among treatments. It can be said that the species and families present in each treatment are acting in the process of natural succession. The structural characteristics evaluated also demonstrated that the sequence is occurring slowly. Regarding the hydrological parameters, there were significant differences between the three areas studied. It can be noticed that the interception and flow through the trunk have increasing behavior as the natural regeneration progresses, while the internal precipitation and the effective precipitation decrease. These results varied according to the characteristics of the vegetation, for example, the quantity and density of individuals in each plot and species present, besides the climatic characteristics and the precipitations incident on the area. It was possible to observe that with the advancement of the natural succession there was an increase in the vegetal parameters and improvement of the soil parameters, on the other hand, the hydrological parameters showed specific behavior for each treatment, indicating that they are able to respond to the state of maintenance and development of the vegetation. / A presença de cobertura vegetal desempenha função reguladora no balanço hídrico através da captação e distribuição da água da chuva dentro dos compartimentos do ecossistema, auxiliando na regulação do escoamento de água pelo solo, bem como no processo de suprimento de água para a recarga de corpos hídricos. É possível dizer que áreas com ausência de vegetação e em estado de degradação não apresentam os mesmos efeitos. Devido à complexidade das interações biológicas com os fatores abióticos do meio, todo o enfoque atual da recuperação ambiental é quase que exclusivo no componente biológico, não se conhecendo em que momento ao longo do desenvolvimento da vegetação, a restauração contribui para a manutenção hídrica, ou em que momento e como irá interferir no balanço hídrico de uma microbacia hidrográfica. O trabalho teve por objetivo caracterizar o comportamento de parâmetros hidrológicos em áreas florestais em diferentes estágios de restauração por condução da regeneração natural a fim de inseri-los como ferramenta para avaliação da restauração. Para isso foi selecionada uma microbacia dentro da Reserva Particular de Patrimônio Natural (RPPN) Floresta das Águas Perenes, Brotas – SP, onde foram demarcadas três parcelas de 400m² para cada tratamento, sendo dois tratamentos com idades distintas de sucessão (Tratamento 1 – 4 anos, e Tratamento 2 – 10 anos) e um fragmento sem interferência humana (Tratamento 3 – 43 anos). A pesquisa caracterizou e avaliou as condições da condução da regeneração natural, através dos indicadores de estrutura da vegetação: altura dos indivíduos arbóreos, diâmetro do tronco, e do solo: cobertura do solo por gramínea e serapilheira, resistência à compactação do solo, umidade e velocidade de infiltração; e luminosidade, além da aplicação de índices de diversidade e riqueza. Em cada parcela foram instalados 12 pluviômetros e escoamento pelo tronco em todas as árvores com CAP>15cm a fim de caracterizar a distribuição da chuva nos três tratamentos através dos indicadores hidrológicos: precipitação a céu aberto, precipitação efetiva, precipitação interna, escoamento pelo tronco e interceptação. Os resultados sobre diversidade e estrutura da vegetação indicaram tendência de incremento da mesma tanto em número quanto em riqueza entre os tratamentos. Pode-se dizer que as espécies e famílias presentes em cada tratamento estão atuando no processo de sucessão natural. As características estruturais avaliadas também demonstraram que a sucessão está ocorrendo lentamente. Com relação aos parâmetros hidrológicos, houve diferenças significativas entre as três áreas estudadas. Pode-se perceber que a interceptação e o escoamento pelo tronco possuem comportamento crescente conforme o avanço da regeneração natural, ao passo que a precipitação interna e a precipitação efetiva diminuem. Tais resultados variaram conforme as características da vegetação, como por exemplo, a quantidade e densidade de indivíduos em cada parcela e espécies presentes, além das características climáticas e das precipitações incidentes sobre a área. Foi possível observar que com o avanço da sucessão natural houve incremento nos parâmetros vegetais e melhoria dos parâmetros do solo, por outro lado, os parâmetros hidrológicos mostraram comportamento específico para cada tratamento, indicando que são capazes de responderem ao estado de manutenção e desenvolvimento da vegetação. / 23112.000670/2015-59
156

Transplante de epífitas entre Florestas Estacionais Semideciduais para enriquecimento de florestas em processo de restauração / Enrichment of forests in process of restoration through epiphytes transplantation, in Semideciduous Seasonal Forest

Marina Melo Duarte 06 March 2013 (has links)
O enriquecimento com diferentes formas de vida, como com epífitas, é fundamental para o desenvolvimento de florestas em restauração, em paisagens fragmentadas, onde a dispersão natural é limitada. Epífitas são plantas que crescem sobre outras (forófitos). Têm papel ecológico importante, realizando ciclagem de nutrientes e oferecendo microambientes e alimentos a outras formas de vida. Características de forófitos, clima e microclima influenciam populações locais de epífitas. Para aumentar o sucesso do enriquecimento em florestas em restauração, é importante determinar quais filtros podem atuar no processo. Fizemos o censo de áreas que receberam autorização para supressão vegetal e obtivemos que, a cada ano, cerca de 500 ha de Florestas Estacional Semidecidual e Ombrófila Densa, em diferentes estágios de regeneração, são desmatados, apenas no estado de São Paulo. Elas podem fornecer material que pode ser recuperado e empregado na restauração de outras florestas. Neste trabalho, damos enfoque às epífitas que podem ser disponibilizadas a partir desse desmatamento. Transferimos 360 indivíduos de seis espécies delas, entre Bromeliaceae (Aechmea bromeliifolia e Tillandsia pohliana), Orchidaceae (Catasetum fimbriatum e Rodriguezia decora) e Cactaceae (Lepismium cruciforme e Rhipsalis floccosa) para duas Florestas Estacionais Semideciduais em processo de restauração, uma com 13 anos e outra com 23. As médias anuais de cobertura de dossel, entre os forófitos escolhidos, variaram entre 62,2 e 85,0% na floresta de 13 anos e entre 79,3 e 92,9% na floresta de 23 anos. Taxas de sobrevivência das diferentes espécies de epífitas foram superiores em floresta mais jovem, variando de 63.33 a 100%, enquanto em floresta mais madura variaram entre 55,17 e 89,66%. Transplantes usando fibra de palmeiras, capaz de reter água, e realizados no início de estação chuvosa podem ter explicado o maior sucesso em floresta mais nova. Taxas de sobrevivência, fixação, ramificação, floração e frutificação não estiveram relacionadas à espécie de forófito, à rugosidade de casca ou à posição de transplante. Por outro lado, elas estiveram relacionadas às espécies das próprias epífitas. Apenas em algumas situações e para determinadas espécies, taxas de fixação, ramificação e reprodução sexuada estiveram relacionadas aos valores de cobertura de dossel. Animais podem ter importantes papéis como polinizadores e dispersores de epífitas, o que mostra que sua presença na floresta é fundamental para a permanência dessas plantas em longo prazo. Ao final, separamos as principais conclusões tiradas deste trabalho e fizemos um guia de procedimentos práticos a serem adotados no enriquecimento de florestas em restauração usando epífitas provenientes de florestas a serem suprimidas. / Enrichment using non-arboreal life forms, such as epiphytes, is critical to the development of forests under restoration, in fragmented landscapes, where natural dispersal is scarce. Epiphytes are plants that grow on top of other plants (phorophytes). They play very important ecological role, performing nutrient cycling and providing microenvironments and food to other life forms. Features of phorophytes, climate, and microclimate influence local diversity of epiphytes. In order to improve success of enrichment in areas under restoration, it is important to determine what filters may play a role in this process. We censused areas that received authorization for vegetation removal and found out that, every year, about 500 ha of Semideciduous Seasonal Forests and Rainforests, in different regeneration stages, are legally cut down, only in the state of Sao Paulo. They can provide material that can be recovered and used to restore other forests. In this work, we focused on the epiphytes that may become available from deforestation. We transferred 360 individuals of six species of this life form among Bromeliaceae (Aechmea bromeliifolia and Tillandsia pohliana), Orchidaceae (Catasetum fimbriatum and Rodriguezia decora) and Cactaceae (Lepismium cruciforme and Rhipsalis floccosa) to two different Semidecidual Seasonal Forests in process of restoration, one of them was 13 years old and the other, 23 years old. Annual canopy cover averages provided by diffferent phorophytes ranged from 62.2 to 85.0% in 13-year old forest and from 79.3 to 92.9% in 23-year-old forest. Survival rates of epiphytes species were higher in the younger forest, from 63.33 to 100%, compared to the ones obtained in the more mature forest, from 55.17 to 89.66%. Transplants performance using palm tree fiber, which enables higher water retention, and at the beginning of rainy season may have been responsible for higher survival rates in the young forest. Survival, rooting, sprouting, flowering and fruiting rates were not related to phorophyte species, to their bark roughness nor to the position of transplantation. On the other hand, they were always relatated to epiphyte species. Only in some cases and for determined species, rooting, sprouting, flowering and fruiting were related to canopy cover. Animals can play important roles as pollinators and dispersers of epiphytes, which shows that their presence in forests is fundamental for the long-term persistance of these plants. In the end, we gathered the main results taken from this work and organized a guide of practical procedures to be adopted in enrichment of areas using epiphytes from forests about to be suppressed.
157

Estudos genéticos de jatobá (Hymenaea courbaril L.) em área natural e restauração florestal com espécies nativas / Hymenaea courbaril L. (jatobá): genetic studies in natural population and forest restoration areas with native species

Lya Carolina da Silva Mariano Pereira 09 October 2017 (has links)
O bioma Mata Atlântica tem sofrido com a fragmentação florestal e como forma de reestabelecer ambientes florestais são realizados plantios de restauração. Porém, por muito tempo houve preocupação somente com a composição florística das áreas e a diversidade genética foi negligenciada. Além disso, muitas áreas são implantadas a partir de sementes coletadas em áreas florestais geralmente pouco conservadas, pequenas e isoladas, o que pode comprometer a qualidade genética das mudas, produzindo indivíduos menos adaptados em decorrência da depressão endogâmica. Assim este trabalho teve como objetivo principal analisar o aspecto genético em áreas de restauração na região do Pontal do Paranapanema e área natural de referência, o Parque Estadual Morro do Diabo (PEMD), utilizando o jatobá (Hymenaea courbaril L.) como espécie modelo. No capítulo 1 com o objetivo de verificar a diversidade genética de H. courbaril em áreas de restauração florestal, foram selecionadas duas áreas de plantio com espécies nativas. Nestas áreas e no PEMD foram coletadas amostras foliares de indivíduos adultos que foram genotipadas para oito locos microssatélites. No PEMD ainda foram coletados frutos em 12 matrizes para caracterização do sistema reprodutivo. As três áreas estudadas apresentaram diversidade genética e níveis de endogamia similares. Nas três áreas de estudo foi identificada baixa estruturação genética espacial. Houve predomínio de fecundação cruzada para a produção de frutos na área natural, porém a taxa de cruzamentos entre indivíduos aparentados foi até dez vezes maior que a observada em outras populações da espécie. No capítulo 2 com o objetivo de verificar se há depressão endogâmica em progênies provenientes do PEMD foram selecionadas 320 sementes de 12 matrizes. Estas e seus frutos foram medidos. As plântulas a que deram origem também foram mensuradas, mensalmente, durante 15 meses. Todos os indivíduos foram genotipadas para oito locos microssatélites. A coancestria, foi estimada e os indivíduos separados em: não aparentados (tu), aparentados (tr) e autofecundação (s). Foi verificada diferença entre as métricas das plantas de acordo com o nível de coancestria entre indivíduos. Também foram estimados os valores de depressão endogâmica (ID). A quantidade de indivíduos irmãos de autofecundação foi muito pequena, sendo a maioria proveniente de cruzamento entre indivíduos não aparentados. A depressão endogâmica por autofecundação foi mais evidente no peso e tamanho dos frutos, e amena ou inexistente para os demais caracteres. Isto provavelmente por estas sementes terem sido coletadas em um fragmento grande e bem conservado e que ainda não sofre as consequências da depressão endogâmica. Assim, nosso trabalho mostrou que áreas de restauração florestal que seguiram as recomendações genéticas de implantação, apresentam diversidade genética suficiente para H. courbaril, podendo estas áreas serem fonte de coleta de sementes no futuro. E que os indivíduos provenientes de sementes do PEMD não apresentaram efeito de depressão endogâmica até 15 meses de desenvolvimento em viveiro. / The Brazilian Atlantic Forest was severely deforested and restoration initiatives are necessary to reestablish environments. However, for a long time there is only concern over floristic composition and the genetic diversity has been neglected. In addition, several restoration areas are planted from seeds collected in forest areas that are generally poorly preserved, small and isolated, which may compromise the genetic quality of the seedlings, producing less adapted individuals due to inbreeding depression. The aim of this work was to analyze the genetic aspects of Hymenaea courbaril L. in restoration areas in Pontal do Paranapanema region, and a natural reference forest, the Morro do Diabo State Park (PEMD), where seeds were also collected. In Chapter 1, to verify the genetic diversity of H. courbaril in areas of forest restoration, using eight microsatellites, two restoration areas were selected. In these areas and in the PEMD, leaf samples from adult individuals were collected. In the PEMD, fruits were collected in 12 seed trees for mating system characterization. The three areas presented similar genetic diversity and levels of inbreeding. Low spatial genetic structure was identified in the three studied areas. In the natural forest, fruits were mainly produced through outcrossings, but the rate of mating among relatives was up to ten times higher than the observed in other H. courbaril populations. In Chapter 2, to verify the inbreeding depression in the PEMD were selected 320 seeds from eight seed trees. The seeeds and their fruits were measured. The seedlings were also measured monthly, during 15 months. All seedlings were genotyped with eight microsatellite loci. From the pairwise coancestry the seedlings were separated into three categories: outcrossing among unrelated individuals (tu), outcrossing among related individuals (tr), and selfing (s). We verified differences among groups in the metrics of seedlings according to the level of coancestry among individuals. The values of inbreeding depression (ID) were also estimated. The number of selfed seedlings were very small, and the majority were from outcrossing among unrelated individuals. Inbreeding depression by selfing was more evident in weight and size fruit, and was insignificant or non-existent for other characters. This is probably because these seeds were collected in a large and preserved forest fragment, that does not suffer the consequences of inbreeding depression yet. Thus, our work showed that forest restoration areas that followed the genetic recommendations present enough genetic diversity for H. courbaril, and these areas may be a source of seeds for collection in the future. Besides that, seedlings from seed trees in PEMD did not present inbreeding depression effect up to 15 months of nursery development.
158

Estimating the willingness-to-pay for restoring indigenous vegetation at selected sites in South Africa

Tessendorf, Sharon Erica January 2007 (has links)
The Working for Water (WfW) Programme is a public works programme designed to clear South Africa of invasive alien vegetation and to restore lowwater consuming indigenous vegetation in the areas that have been cleared. Funds to clear alien invasives were initially secured on the basis that such a programme would increase water runoff, facilitate biodiversity and ecosystem functioning, and provide social benefits through job creation. The economic merits of the Programme, in terms of increased water yields, has been established in the Western Cape and KwaZulu-Natal, but questioned in the Eastern and Southern Cape. However, there are economic aspects of the studies carried out in the Eastern and Southern Cape that merit more attention than was given them; one of these being the issue of non-water benefits. Preliminary figures emanating from contingent valuation pilot studies conducted at six WfW projects sites indicated that one of these non-water benefits, namely the biodiversity and ecosystem resilience benefit, could be substantial. As such, the primary objective of the present study was to apply the contingent valuation method (CVM) to value people’s preference for indigenous vegetation. This value was intended to serve as a proxy for increased biodiversity and ecosystem resilience at three WfW sites. Despite the controversy surrounding the CVM, it has been found that it is a credible valuation tool. The CVM’s merits lie in its versatility and in the fact that it is the only method available which is capable of obtaining estimates of both nonuse and use values, thus making it applicable for valuing biodiversity. The primary aim of a CVM study is to determine an estimate of the total willingness-to-pay (WTP). In this study, the total WTP figure was calculated by multiplying the median WTP for the local WfW Programme by the total number of user households. The respective total WTP amounts are shown in Table 1. It was anticipated that respondents would be willing to pay more for the national WfW Programme, than for the less inclusive good (i.e. the local WfW Programme). The results correspond with this expectation at the Port Elizabeth and Underberg sites. However, due to strategic factors Worcester respondents were willing to pay more for the local WfW Programme than for the national Programme.
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Viabilidade genética de restaurações florestais : diversidade e estrutura genética em Myroxylon peruiferum L.f. / Genetic feasibility of forest restorations : genetic diversity and structure in Myroxylon peruiferum L.f.

Schwarcz, Kaiser Dias, 1982- 26 August 2018 (has links)
Orientadores: Maria Imaculada Zucchi, Ricardo Ribeiro Rodrigues / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-26T12:21:20Z (GMT). No. of bitstreams: 1 Schwarcz_KaiserDias_D.pdf: 5972760 bytes, checksum: 6089d106796adfd5fab684651bfb298e (MD5) Previous issue date: 2014 / Resumo: A degradação ecológica e o desflorestamento são processos que se iniciaram há muito tempo e cuja história confunde-se com a da agricultura. A Mata Atlântica é a segunda maior floresta tropical em ocorrência e importância na América do Sul, possuindo grande diversidade biológica e altos níveis de endemismo. A ocupação desordenada da Mata Atlântica causou sua redução a 11,26% de sua área original, com distribuição de forma fragmentada pelo território brasileiro. A destruição da Mata Atlântica tem resultado na eliminação de muitas populações e, potencialmente, na erosão da diversidade genética de diversas espécies. Essa combinação de alto endemismo e forte ameaça de extinção, faz com que a Mata Atlântica seja considerada um hotspot para a conservação. Nas últimas décadas a recuperação de ecossistemas degradados recebeu a atenção da comunidade científica, dando origem ao campo do conhecimento chamado Ecologia da Restauração, que se dedica aos estudos teóricos dos princípios, práticas, resultados e conseqüências de projetos de restauração. O estudo e monitoramento de áreas de restauração florestal é essencial para melhorar as técnicas de restauração em ecossistemas tropicais e subtropicais. Para que uma determinada espécie se perpetue em uma área em processo de restauração, é preciso que a mesma desenvolva todo o seu ciclo de vida e que gerem descendentes capazes de se desenvolver a ponto de substituir as árvores mães quando as mesmas entrarem em senescência. Por isso há a necessidade de se estudar a variabilidade genética de populações arbóreas dentro de áreas de floresta restaurada, assim como a ocorrência e efetividade do fluxo gênico entre estas áreas e os fragmentos de seu entorno. Neste trabalho, estudamos a variabilidade genética de Myroxylon peruiferum L. f., em duas diferentes áreas de restauração florestal e em duas áreas de remanescentes naturais de Floresta Estacional Semidecidual. Nossos resultados indicam que as restaurações florestais de Cosmópolis e Iracemápolis conservam diversidades genéticas HE e alélicas semelhantes às de remanescentes naturais. A principal diferença entre áreas naturais e restauradas foi a menor riqueza de alelos endêmicos nestas últimas o que é um efeito de amostragem que favorece a perda de alelos raros. A área de restauração florestal mais antiga em Cosmópolis apresentou uma estruturação genética espacial compatível com a de áreas naturais. O mesmo não ocorreu com a restauração mais recente de Iracemápolis. Observou-se a ocorrência de estruturação genética local nas áreas naturais e na área de restauração mais antiga e indícios de fluxo gênico entre os áreas nativas e restauradas. Um estudo adicional do efeito de amostragem sobre as freqüências alélicas demonstrou o fenômeno de perda de alelos com baixa freqüência em eventos de amostragem. O mesmo trabalho indicou que uma amostra de cerca de 30 indivíduos é capaz de representar adequadamente alelos com freqüências acima de 0,05; sendo este um bom número a se considerar na seleção de matrizes para fornecimento de mudas para restauração florestal / Abstract: Ecological degradation and deforestation are processes that started long ago and whose history is intertwined with that of agriculture. Atlantic Forest is the second largest rainforest in occurrence and importance in South America, having great biological diversity and high levels of endemism. Disordered occupation of Atlantic Forest caused its reduction to 11.26% of the original area, with distribution in forest fragments poorly conected across the Brazilian territory. Destruction of the Atlantic Forest has resulted in the elimination of many populations and potentially the erosion of genetic diversity of several species. This combination of high endemism and strong threat of extinction causes the Atlantic Forest to be considered a hotspot for conservation. In the last decades recovery of degraded ecosystems has received attention from the scientific community giving birth to an new area of knowledge called the Restoration Ecology. The study and monitoring of areas of forest restoration is essential to improve restoration techniques in tropical and subtropical ecosystems. For a given species to perpetuate itself in an area undergoing a restoration process, it needs to develop its whole life cycle and generates progeny capable of developing to the point of replacing mothers trees when they die. Therefore there is a need to study the genetic variability of tree populations within areas of restored forest, as well as the occurrence and effectiveness of gene flow between these areas and surrounding fragments. We studied the genetic variability of Myroxylon peruiferum L. f., in two different areas of forest restoration and in two areas of natural remnants of semideciduous forest. Our results indicates that restorations in Cosmopolis and Iracemápolis conserve genetic and allelic diversity HE similar to that of natural remnants. The main difference between natural and restored areas was the lowest richness of endemic alleles which is the result of a sampling effect that favors the loss of rare alleles. The area of older forest restoration in Cosmopolis presented a spatial genetic structure consistent with natural areas. This did not occur with the newer restoration in Iracemápolis. We observed the occurrence of local genetic structure in natural areas and in the area of older restoration and evidence of gene flow between native and restored areas. An additional study about the effect of sampling size on allele frequencies showed the phenomenon of loss of low frequency alleles in sampling events. The same study found that a sample of about 30 individuals are able to adequately represent alleles with frequencies above 0.05; this is a good number to consider in selecting matrix trees to supply seedlings for forest restoration / Doutorado / Genetica Vegetal e Melhoramento / Doutor em Genetica e Biologia Molecular
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Redes mutualísticas na avaliação da restauração da Mata Atlântica = Mutualistic networks in evaluation of restoration in the Atlantic forest / Mutualistic networks in evaluation of restoration in the Atlantic forest

Silva, Fernanda Ribeiro da, 1978- 05 May 2015 (has links)
Orientadores: Ricardo Ribeiro Rodrigues, Marco Aurélio Pizo Ferreira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T12:03:15Z (GMT). No. of bitstreams: 1 Silva_FernandaRibeiroda_D.pdf: 2601060 bytes, checksum: 638333ef8a36efaf997c27c9ecd0a5fb (MD5) Previous issue date: 2015 / Resumo: As atividades humanas têm levado à perda de habitats e da biodiversidade na floresta Atlântica. A restauração ecológica é uma estratégia para a reconstrução desse bioma e deve incluir não só o restabelecimento das espécies, mas também das complexas interações e funções ecológicas que essas interações fornecem ao ecossistema. Um desses importantes processos é a dispersão de sementes realizada pelos animais frugívoros. A dispersão de sementes pode ser analisada numa abordagem de redes de interações, úteis no entendimento do funcionamento do ecossistema. Nós estudamos redes de dispersão de sementes em três áreas restauradas a 15, 25 e 57 anos atrás, escala temporal raramente estudada em estudos de restauração. Nós investigamos mudanças na estrutura das redes (aninhamento, modularidade e especialização da rede) em cada uma dessas comunidades ao longo do tempo de restauração. Embora o tamanho da rede e o número de interações tenham aumentado com a restauração, as espécies que compuseram a rede foram generalistas, sendo que os grandes frugívoros estiveram ausentes. Contrário a nossa expectativa, a riqueza de espécies foi maior na área de 25 anos, talvez devido ao plantio ter sido realizado com maior número de espécies. O aninhamento foi baixo nas três redes, sendo maior na área de idade intermediária. Entretanto a área mais antiga foi significativamente modular e apresentou alta especialização. Estes resultados sugerem que 57 anos após a restauração a complexidade das redes de interações mutualísticas aumentou, assim melhorando as funções ecossistêmicas na floresta Atlântica. Nós juntamos as três redes de dispersão de sementes restauradas em uma para identificar a contribuição individual das espécies na organização e funcionamento da rede, medidas pelo aninhamento, modularidade e força de interação. Através dessas abordagens apontamos as espécies e os grupos funcionais mais importantes para a resiliência e persistência das redes de dispersão de sementes e que devem ser priorizados nas ações de restauração da Mata Atlântica / Abstract: Human activities have lead to the loss of habitats and biodiversity in the Atlantic Rain Forest in Brazil. Ecological restoration aims to rebuild this biome and should include not only the reinstatement of species, but the reestablishment of complex ecological interactions and the ecological functions that they provide. One such function is seed dispersal, which is provided by the interactions between animal frugivores and plants. We studied seed dispersal networks in three different tropical forest sites restored 15, 25 and 57 years ago, temporal scales rarely observed in restoration studies. We investigated changes in network structure (nestedness, modularity and network specialization) in these communities over restoration time. Although network size and the number of interactions increased with time since restoration, the networks were composed of generalist birds, and the large frugivores remained absent. Contrary to our expectations though, species richness was highest in the 25 years old site maybe due the highest number of species used in the planting. Nestedness values were low in all three networks, but the highest nestedness was observed in the intermediate aged site. However, the oldest network was significantly modular and showed higher complementary specialization. These results suggest that, 57 years after restoration, the complexity of mutualistic interactions in seed dispersal networks has increased, this enhancing ecosystem function in the Atlantic forest. Furthermore, we merged all three networks in a big one to identify which are the most important species in terms of nerwork organization (modularity and nestedness) and interaction strength. Through this approach we point out species and their functional groups most important to persistence of seed dispersal networks. These species and their functional groups should be indicated to maximize the restoration in the Atlantic forest / Doutorado / Biologia Vegetal / Doutora em Biologia Vegetal

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