Thesis (Ph. D.)--Auburn University. / Abstract. Vita. Includes bibliographical references.

Thesis (Ph. D.)--Auburn University, 2008. / Abstract. Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2005. / Printout. Includes bibliographical references (leaves 123-137). Also available on the World Wide Web.

Thesis (M.S.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 14, 2009) Includes bibliographical references.

Thesis (M. Sc.), Memorial University of Newfoundland, 1999. / Bibliography: p. 53-61.

No description available.

This paper explores the characterization of a riparian bottomland forest in north central Texas in two ways: field study, and computer simulation with the model ZELIG. First, context is provided in Chapter One with a brief description of a southern bottomland forest, the ecological services it provides, and a history of bottomland forests in Texas from the nineteenth century to the present. A report on a characterization study of the Lake Ray Roberts Greenbelt forest comprises Chapter Two. The final chapter reviews a phytosocial study of a remnant bottomland forest within the Greenbelt. Details of the ZELIG calibration process follow, with a discussion of ways to improve ZELIG's simulation of bottomland forests.

This dissertation aims to advance understanding of the social and ecological dynamics that transform riparian forests and the human and non-human communities that depend on riparian resources. The four articles that comprise this dissertation examine the causes and consequences of social-ecological transformations in the riparian zone of the transboundary San Pedro River watershed, located in the Sonoran Desert borderlands of southern Arizona, USA and northern Sonora, Mexico. The research utilizes an interdisciplinary, mixed methods approach that combines interviews with key informants (including natural resource managers, ranchers, local residents, and political figures), archival research and historical document review, spatial analysis and synthesis of binational datasets, and land use classification and change detection at the watershed scale using methods from remote sensing and geographical information systems.This research is motivated by two objectives. First, I aim to examine how shifts in social and ecological systems have transformed riparian spaces in the transboundary San Pedro River watershed. Second, I intend to assess the consequences of these riparian transformations for the human and ecological communities who depend on riparian resources for survival. Based on these two overarching objectives, there are three interrelated research questions that drive the research and analysis presented in the four chapters of this dissertation: 1) How are social-ecological processes at the watershed scale affecting access to water resources in the riparian zone?; 2) How are shifting relations of access to water and riparian-zone resources influencing and differentiating levels of exposure to hazards over space and across time?; and 3) Following a disturbance event, how are capacity to respond and recover from disturbance and expectations of accountability shifting over space and across time? The findings of this research suggest three broad results. First, social processes of accumulation of land and water resources by the state and industry are creating uneven spatial and temporal experiences of water security and insecurity by shifting the amount, timing, and quality of water resources available and who can physically access the riparian zone to derive benefits from riparian resources. Specifically, the three social processes of resource accumulation that I examine are privatization, expropriation, and conservation. Second, transformations in social-ecological system (SES) dynamics and access to riparian resources differentially impact the production of water insecurity (water quality and water quantity) both between and within communities and economic sectors that depend on riparian resources. Third, the ability for local communities and small-scale agricultural producers to cope with increasing water insecurity and respond to disturbance events is decreasing due to three interrelated causes. The first is limited access of local communities to the wealth and adaptive assets produced from natural resource extraction in the region. The second is the shift at the state and community level toward increasing individuation of responsibility for ensuring livelihood security. And the third is a culture of evasion of accountability to remediate ecological degradation within the transnational mining industry.

O presente trabalho teve como objetivo avaliar reflorestamentos de espécies nativas da Mata Atlântica quanto à estimativa dos estoques de carbono na parte aérea lenhosa dos plantios sob diferentes idades e diversidade de espécies, comparando com remanescentes ciliares próximos às áreas de restauração, visando gerar respostas quanto ao seqüestro de carbono na parte aérea lenhosa dos plantios de espécies nativas em áreas ciliares. As áreas de restauração e matas nativas ciliares amostradas encontram-se na bacia do rio Tietê, em região de Floresta Estacional Semidecidual, às margens do reservatório da Usina Hidrelétrica de Três Irmãos, distribuídas nos municípios de Andradina, Araçatuba, Pereira Barreto, Sud Menucci, Santo Antônio do Aracanguá e Birigui - SP. Os plantios de restauração variam quanto à idade, diversidade de espécies e estabelecimento da cobertura florestal. A área total dos reflorestamentos é de 2.860 hectares. Para o cálculo do acúmulo de carbono na parte aérea lenhosa foram amostradas 75 parcelas (24 m X 18 m) em áreas de plantios e 9 parcelas nos remanescentes ciliares, onde foram medidos todos os indivíduos arbóreos com diâmetro à altura do peito - DAP > 3 cm. Foi calculada a área basal, densidade de árvores por hectare, diversidade e freqüência de espécies florestais, carbono médio por hectare e incremento médio anual de carbono, além de realizada análise qualitativa das parcelas. Para a estimativa de carbono foi admitido erro desejado de 10% e 90% de probabilidade da média. Os reflorestamentos apresentam alta variabilidade de sobrevivência e estoque de C devido a aspectos de qualidade de sítio e qualidade plantio e manutenção. No entanto, em média os reflorestamentos tem mostrado um incremento médio anual nas diferentes classes de idade variando de 0,72 a 1,76 Mg C ha-1ano-1, e com valor estimado de cerca de 1,07 Mg C ha-1 ano- 1 na idade de 20 anos. As matas nativas vizinhas amostradas mostram também ampla variação de estoque devido a perturbações, com estoque médio de 35,45 Mg C ha-1. Considerando-se a manutenção das taxas de crescimento dos reflorestamentos com 20 anos, levaria em torno de mais 15 anos para atingirem o estoque médio das matas ciliares do entorno. Os plantios mais jovens mostram maior sobrevivência e maiores taxas de crescimento que plantios mais antigos, fato este que deve estar ligado às melhores práticas silviculturais de preparo de solo, controle da matocompetição e fertilização. Um total de 84 espécies florestais arbóreas foram identificadas, sendo que 19 delas respondem por 85% dos indivíduos amostrados e 82% dos estoques de carbono, sendo predominantemente pioneiras. Os plantios podem ser classificados como plantios jovens, com predomínio de espécies pioneiras e em estágio inicial de sucessão. / This study evaluated Atlantic Forest species restoration estimating aboveground carbon stocks across different sites and age-classes and compared them with local remnants forest areas. The restoration sites and native forests were located in the Tiete river basin, in a semi deciduous forest type on the shores of the Tres Irmaos CESP Dam, which comprehends the municipalities of Andradina, Aracatuba, Pereira Barreto, Sud Menucci and Santo Antonio do Aracangua in Sao Paulo State. The restoration stands ranged from 4 to 20 year-old and the total reforested are was 2,860 ha. The aboveground carbon stocks of the restored forest were calculated for 75 plots (24 m x 18 m) in plantation areas and 9 plots in the residual forests. All trees with diameter at breast height - DBH> 3 cm were measured. We calculated the basal area, DBH, density of trees per hectare, diversity and frequency of forest species and average carbon stock per hectare, and performed qualitative analysis of plots. The confidence interval of the carbon estimates was calculated (10% error, 90% probability). The reforestation present high variability of survival and C stocks due to aspects of site quality and maintenance operations. On the annual increment of the restoration ranged from 0.72 to 1.76 Mg C ha-1 yr- 1, and with an estimated value of about 1.07 Mg C ha-1 yr-1 for the age of 20 years. The residual native forests also show large C stock variation due to disturbances averaging 35.45 Mg C ha-1. Considering the maintenance of growth rates at age 20 years it would take another 15 years to reach the average stock of the riparian forests. Younger stands also show higher survival and higher growth rates than older plantings which is probably related to the best silvicultural practices of soil preparation, controlling of invasive grasses and fertilization. A total of 84 forest tree species were identified and 19 of them account for 85% of the individuals and 82% of carbon stocks, been predominantly pioneers. Plantings can be classified as young plantings, with a predominance of pioneer species and in early stages of succession.

A expansão agrícola no Cerrado brasileiro vem causando severos impactos negativos decorrentes do manejo inadequado das terras. Um destes impactos é a erosão em campos de cultivo que gera grande quantidade de sedimentos, os quais podem ser interceptados em faixas vegetadas com espécies arbóreas ou gramíneas. Várias medidas conservacionistas são indicadas para a minimização destes impactos, dentre elas a presença de cobertura florestal nativa ao longo dos cursos dágua. As matas ciliares funcionam como corredores ecológicos que favorecem a biodiversidade e colaboram na manutenção da qualidade do solo e da água. A largura fixa e simétrica dessa faixa de vegetação conforme proposto pela legislação, em algumas situações se mostra ineficiente, porém a largura ideal ainda permanece controversa. Com o objetivo de propor novas informações acerca da largura ótima para Áreas de Preservação Permanente (APP´s) o presente estudo analisa as matas ciliares de forma multidisciplinar, onde são considerados diversos fatores que influenciam na dinâmica do ecossistema ripário. Fatores climáticos, geomorfológicos e pedológicos são relacionados e focados na interação das matas ciliares com os processos erosivos e seus impactos intrínsecos. Foram utilizadas técnicas convencionais para estudos de solos, como análise estrutural, análise granulométrica em soluções dispersantes (NaOH e H2O) e micromorfologia, técnicas pertinentes a estudos geomorfológicos como uso de pinos de erosão, além de técnicas inovadoras como a dendrogeomorfologia que utiliza as árvores como testemunho temporal de processos ambientais. Dessa forma foram avaliados espaço-temporalmente os sedimentos depositados nas nascentes da zona ripária da microbacia hidrográfica do Rio Meia Ponte. A análise integrada da granulometria e da micromorfologia dos solos e sedimentos revelou a predominância da sedimentação ao longo da borda da mata ciliar. A deposição de sedimentos na área de estudo varia intensamente (coeficiente de variação de 77,76%) tanto no espaço como no tempo, tendo sido observada a deposição de até 37 cm de sedimentos em alguns locais e, a erosão de até 14 cm na superfície em outros. Sendo que de um mês para outro também foi observada alternância entre sedimentação e erosão num mesmo local. A análise dendrogeomorfológica evidenciou que nos últimos 15 anos houve a deposição de até 50 cm de sedimentos. A deposição de sedimentos na área de estudo ocorre distribuída de forma geral na área numa média de 12 cm, bem como de forma localizada próxima aos sulcos de erosão (voçorocas efêmeras) e às raízes tabulares de árvores como figueiras (Ficus insípida).Os maiores índices de sedimentação ocorreram no verão de 2008/2009 quando chuvas muito intensas atingiram o solo descoberto. A ocorrência de voçorocas que atravessam tanto o campo de cultivo quanto a zona ripária reduz a eficiência da mata ciliar na retenção de sedimentos. Outro impacto negativo de grande proporção é o soterramento das nascentes e plântulas que afetam a regeneração da floresta. / Agricultural expansion in the Brazilian Savanna causes several negative impacts due to inappropriate land use. One of these impacts is represented by soil erosion in agricultural fields producing big amounts of sediment, which can be intercepted by vegetated areas with pastures or arboreous species. Several conservationist techniques are indicated to minimize these impacts, including maintenance of native vegetal coverage along water courses.Riparian forests act as ecological corridors promoting biodiversity and collaborating in water and soil quality maintenance. The symmetric and fixed width of vegetated stripes proposed by law is inefficient in some situations, and the ideal width is still controversial . With the purpose of proposing new data about the ideal width for permanent preservation areas (APPs), this study analyzes riparian forests in an integrated way taking into account several factors that influence the dynamic of riparian ecosystems. Climatic, geomorphological and pedological factors are related and focused in interaction with riparian forests, erosion processes and related intrinsic impacts. Conventional techniques were used for the soil studies such as structural analysis, particle size distribution analysis with dispersive solutions (NaOH and H2O) and micromorphology. Other techniques were used for geomorphological studies like erosion pins and dendrogeomorphology that uses trees as a temporal evidence of environmental processes. Using these techniques the spatial-temporal distribution of sediments deposited on the sources located in the riparian zone of the basin of Meia Ponte river, was studied. The integrated analysis of particle size and morphology of soils and sediments revealed the dominance of sedimentation along the edge of the riparian forest. The deposition of sediments in the study area varies greatly (coefficient of variation of 77.76%) both in space and time, the deposition was observed up to 37 cm of sediments in some locations, and erosion of up to 14 cm in surface in others. From one month to another was also observed alternation of sedimentation and erosion in one place. The dendrogeomorphic analysis showed that in the last 15 years there was deposition of sediment of up to 50 cm. Sediment deposition in the study area is generally distributed in an average of 12 cm, and locally next to rills (ephemeral gullies) and tabular roots of trees such as figs (Ficus insipida). The biggest rates of sedimentation occurred in the summer of 2008/2009 when very intense rains hit bare soil. The occurrence of gullies that cross both the field and the riparian zone and reduces the efficiency of riparian forest on sediment retention. Another negative impact is the large proportion of the springs and seedling burial that affect forest regeneration.