The overall aim of this study was to develop an understanding of the vegetation ecology of the lower Mkuze River floodplain from a landscape ecology perspective. The lower Mkuze River floodplain and its associated wetlands are located east of the Lebombo Mountains and north of Lake St. Lucia on the Maputaland Coastal Plain in northern KwaZulu-Natal. This system is defined as a storage floodplain wetland and comprises a mosaic of different wetland types. In addition it has a complex history of resource use and management. Landscape ecology proved to be an ideal theoretical framework for this study because it enables the examination of complex ecological processes and phenomena in an integrated and holistic manner. It achieves this by explicitly recognizing the spatial heterogeneity, dynamics and hierarchical organization of the landscape; concepts that proved useful in developing an understanding of the ecological patterns and processes operating within the lower Mkuze River floodplain. The vegetation of the study area was classified, using multivariate techniques, into six plant communities. The distribution of these plant communities was correlated with underlying environmental gradients that summarized the interactions between hydrology, substrate properties and topography within the floodplain system. Within the study area the Phragmites mauritianus reed swamp community was found where there was slow moving water, in semi- to permanently saturated soil. This was usually around the edges of pans or in extensive stands in low-lying areas in the distal reaches of the floodplain. The Imperata cylindrica hygrophilous grassland community was uncommon and was found in isolated stands towards the edge of the region of seasonal flooding. The Echinochloa pyramidalis backswamp community was the most extensive of all the plant communities identified. This community was tolerant of flooding and was found in damp places such as seasonal pans, backswamps and riverbanks as well as in standing water. The distribution of the Ficus sycomorus riparian forest community was restricted to elevated levees adjacent to the river channel that experienced inundation when floods were large enough to overtop channel banks. The Cynodon dactylon floodplain community was generally found towards the floodplain-terrestrial upland boundary in elevated areas with sandy well-drained soils. The Acacia xanthophloea woodland community was distributed on the floodplain margin in elevated areas on sandy soils, primarily fringing the linear pans draining towards the Mkuze River from the north. The description of the plant community types and the underlying environmental determinants of their distribution provided a useful foundation for the examination of ecological processes and phenomena operating at spatially coarser levels within the landscape hierarchy. Plant communities were aggregated into functional types based on criteria such as exposure to similar flooding and sedimentation regimes. The identification and mapping of these functional types, using a Geographical Information System (GIS), enabled one to identify a hydrogeomorphic continuum that described the interaction between floodplain processes and vegetation distribution. Within the study area the proximal-seasonally inundated functional type comprised plant community types found on channel levees and within backswamp areas. These areas were functionally connected to the Mkuze River in that they were exposed to seasonal flood events and associated sedimentation. The distal-permanently inundated functional type was typically found in the lower reaches of the floodplain that were rarely exposed to hydrological and sedimentological inputs from the Mkuze River. This functional type was permanently inundated and characterized by standing water and/or permanently saturated soils that were generally associated with the large floodplain pans. The distal-infrequently inundated functional type was typically located in sandy areas along the southern distal reaches of the floodplain. These areas were infrequently inundated by overbank floodwaters from the Mkuze River and were not characterized by substantial clastic sedimentation. The distribution and interaction between these functional types made it possible to develop process-based understanding of the ecosystem patterns and processes operating within the lower Mkuze River floodplain. Landscape ecology theory emphasises the importance of a temporal analysis of spatial heterogeneity and the role of disturbance in ecosystem patterns and processes. Therefore a temporal analysis of the landscape mosaic from 1937 to 1996 was undertaken, using a GIS, in order to quantify landscape change over time. The landscape characteristics utilised to examine this change were total category area, percentage contribution to the total landscape area, number of patches, mean patch size, median patch size, patch size standard deviation and the mean perimeter-area ratio. These spatial statistics were calculated for each year using PATCH ANALYST, an ArcView GIS extension and they were used to illustrate the role of anthropogenic disturbance on the landscape mosaic at a variety of levels within the landscape hierarchy. Anthropogenic disturbance was found to affect landscape content and configuration and therefore had the potential to undermine the underlying environmental determinants of landscape patterns and processes. Once the underlying functional processes are undermined, irreversible ecosystem degradation is a possible outcome. The examination of the different levels within the landscape hierarchy and the dynamics of ecosystem patterns and processes operating within the Mkuze River floodplain made it possible to develop deeper insights into ecosystem patterns and processes than a conventional vegetation ecology study that typically focuses primarily on plant community classification. The use of landscape ecology as an overarching theory that guided the research process and aided the interpretation of findings by explicitly recognising the importance of examining spatial heterogeneity, hierarchical organisation and dynamics, proved invaluable in developing process-based understanding of the lower Mkuze River floodplain. / Thesis (M.Sc.)-University of Natal, Durban, 2001.

Using a comparative approach, the presented study explores the ecology of ten species of native New Zealand broom, Carmichaelia, and their vulnerability to competition and herbivory, with the aim of gaining a better understanding of the significance of introduced species as a threat to rare indigenous plants in New Zealand. In particular, the study focuses on the relationship between characteristics of the Carmichaelia species and their vulnerability, as well as on other factors influencing the significance of introduced species as a threat. To gain a better understanding of the ecology of the Carmichaelia species, their current habitats and associated plant communities were investigated using quantitative-descriptive methods in the field. The effect of competition with introduced plants was studied in two glasshouse experiments, differentiating above ground competition for light from below ground competition for nutrients and water. The experiments focussed on the early life-stage of seedling establishment of the Carmichaelia species. The impact of herbivory by introduced mammals was studied in four field-based exclosure trials, focussing on the effects on survival and reproductive activity of adult Carmichaelia plants. The results showed that the effects of competition and herbivory vary between the different species. Furthermore, they provided a set of species characteristics that can be used as indicators to predict the vulnerability of Carmichaelia to the impact of introduced species. These indicators provide a useful tool for threatened species management, as they allow the identification of the most vulnerable species as well as the most significant threat to each species. Furthermore, the indicators can be used to group species, combining those with similar vulnerability profiles, and therefore, likely similar management needs. However, the example of the Carmichaelia species also illustrated that the use of indicators for the vulnerability of threatened species is limited and needs to be combined with case-by-case studies to verify the actual significance of threats for each population of concern. The vulnerability profiles derived from species’ characteristics can be used to guide such site specific studies, ensuring they focus on the most relevant threat factors. This combination of the understanding of general patterns in the vulnerability of species with targeted species and site-specific studies will lead to increased efficiency in the conservation management of threatened plant species.

El presente trabajo de investigación analiza la fitogeografía, fitosociología y ecología de la vegetación de los saladares en el Chaco Boreal, Paraguay. El estudio hace hincapié en las características florísticas, ecológicas y estructurales de la vegetación a lo largo del gradiente salino desde zonas bajas con suelos fuertemente salinos hasta zonas con un relieve elevado y una influencia salina moderada. El área de estudio se encuentra ubicado en la franja de salinización que aparece en la zona de transición entre el Chaco húmedo y el Chaco central seco. Debido a las características geológicas y climáticas se desarrollan en esta zona fenómenos de salinzación en lagunas, riachos y cauces. Estos fenómenos de salinización son en gran parte naturales y se encuentran ligados a la napa freática salada y elevada en la zona. Los relevamientos fitosociológicos se realizaron en 14 lugares de muestreo durante los meses de verano de 2010-2012. Con un muestreo aleatorio estratificado fueron realizados 162 inventarios en las estepas salinas y 236 inventarios en la vegetación leñosa adyacente. Los inventarios fitosociológicos en vegetación fisionómicamente homogénea fueron acompañados de caracterizaciones ecológicas del hábitat. En coincidencia con inventarios florísticos en otros saladares continentales de Sudamérica, el área de estudio se caracteriza por una diversidad baja de especies. De las especies vegetales presentes en el Chaco paraguayo, fueron encontrados 18,9 % en el área de estudio y sólo 2,6 % en las estepas salinas. En la vegetación analizada dominan los géneros pantrópicos y neotrópicos. A nivel de especies se puede observar una marcada predominancia de especies con distribución neotrópica en sentido amplio. Las especies típicas de la provincia fitogeográfica chaqueña juegan en este sentido un rol especial en la composición florística. El espectro de las formas de vida y la distribución geográfica a lo largo del gradiente de precipitación de las especies en el área de estudio fueron comparados con la checklist de la flora vascular del Chaco paraguayo preparada y publicada recientemente por el autor. En el Chaco paraguayo y también en el área de estudio predominan las fanerófitas, mientras que las estepas salinas se encuentran dominadas por las hemicriptófitas. En las estepas salinas fueron clasificadas nueve comunidades vegetales con secuencias bien definidas y generalmente sin transiciones graduales entre ellas. La mayoría de las comunidades se caracteriza por una sola especie diferencial respectivamente. Las comunidades diferenciadas se encuentran ubicadas a lo largo de un gradiente de disponibilidad de agua, desde la comunidad hidrohalófila de Ruppia maritima y la comunidad higrófila de Setaria geminata en suelos húmedos y salobres hasta la comunidad xerohalófila de Heterostachys ritteriana. El contenido de sodio y la materia orgánica en los horizontes superiores del suelo tienen una influencia significativa en la distribución de las especies en las estepas salinas. Setaria geminata se desarrolla en suelos húmedos con cierto porcentaje de materia orgánica y muy bajo contenido de sodio. En los suelos con alto contenido de sodio predominan generalmente Heterostachys ritteriana y Sarcocornia ambigua. Pequeñas diferencias del relieve juegan además un importante rol en la distribución de las especies porque influyen en forma decisiva las sedimentaciones, la disponibilidad de agua y la duración de la inundación. Acumulaciones de sedimentos arenosos reducen la humedad y la salinidad y facilitan el crecimiento de especies pioneras como Sesuvium portulacastrum y Sporobolus pyramidatus. Las diez comunidades vegetales diferenciadas en la vegetación leñosa de los saladares del Chaco paraguayo se encuentran ubicados a lo largo de un gradiente de humedad y salinidad. A lo largo de este gradiente aumenta la diversidad estructural y de las especies y disminuye el procentaje de especies halófilas. El contenido de sodio y el porcentaje de arena y limo en el suelo tienen una influencia significativa en la distribución y composición de las especies en las comunidades arbustivas y boscosas. Altos contenidos de sodio y pH están positivamente correlacionados y caracterizan suelos salinos. En estos hábitats se desarrollan principalmente especies halófilas, entre ellas varios arbustos como Cyclolepis genistoides, Lophocarpinia aculeatifolia, Lycium americanum, Lycium boerhaaviaefolium y Prosopis rojasiana. Altos porcentajes de limo y arcilla en el suelo caracterizan suelos mal drenados e influyen significativamente la composición de las especies en una comunidad determinada. Este efecto se pudo observar especialmente en las comunidades de Parkinsonia aculeata-Copernicia alba, Prosopis ruscifolia-Sporobolus pyramidatus, Prosopis ruscifolia-Evolvulus convolvuloides y Prosopis ruscifolia-Tabebuia nodosa. Mediante mediciones estructurales de los troncos con un DAP ≥10 cm fueron calculados la abundancia, frecuencia, dominancia y el índice de valor de importancia (IVI) para las especies leñosas presentes en cada comunidad. En las comunidades arbustivas la especie más abundante y frecuente es Prosopis ruscifolia, mientras que la especie con mayor abundancia y frecuencia en las comunidades boscosas es Salta triflora. En el presente trabajo se comparan las comunidades vegetales diferenciadas en los saladares del Chaco paraguayo con otros estudios similares en el contexto sudamericano y se presenta una esquema sintaxonómico de las mismas. Las comunidades vegetales de las estepas salinas y tambien de la vegetación leñosa pueden ser clasificadas en tres clases sintaxonómicas respectivamente. Teniendo en cuenta las alteraciones climáticas y el constante aumento del uso de la tierra en el Chaco paraguayo se realiza al final del trabajo una discusión acerca de las consecuencias y posibles pronósticos de desarrollo en los saladares. Además se presentan algunas recomendaciones para futuras investigaciones, usos alternativos y medidas necesarias para la conservación de los saladares estudiados. / Die vorliegende Arbeit befasst sich mit der Pflanzengeographie, Pflanzensoziologie und Ökologie der salzbeeinflussten Vegetation im Chaco Boreal von Paraguay. Im Mittelpunkt der Betrachtungen stehen die floristischen, strukturellen und ökologischen Merkmale der Vegetation entlang eines Gradienten von stark salzhaltigen bis zu mäßig salzbeeinflussten Standorten und die daraus resultierende vegetationsökologische Charakterisierung. Das Untersuchungsgebiet liegt in der Übergangszone von den regelmäßig überschwemmten Flächen des feuchten Ostchaco zum trockenen Zentralen Chaco, in der als Folge der klimatischen und geologischen Verhältnisse großflächige Salzstandorte vorkommen. Versalzungen, die in dieser Zone auf natürliche Weise entstehen, treten hier im Bereich von Niederungen und Unterläufen periodisch wasserführender Flusssysteme auf und stehen in enger Verbindung zum hochanstehenden salzigen Grundwasser. An insgesamt 14 Untersuchungsorten wurden 162 stratifiziert-randomisierte Vegetationsaufnahmen in den Salzmarschen und 236 Aufnahmen in der angrenzenden salzbeeinflusten Gehölzvegetation durchgeführt. Den Bestandsaufnahmen in physiognomisch unterscheidbarer homogener Vegetation folgten Untersuchungen einiger Standortfaktoren. Die untersuchten Salzstandorte sind in Übereinstimmung mit Studien anderer Binnenlandsalzstellen in Südamerika artenarm. Von den im paraguayischen Chaco vorkommenden Arten wurden an den untersuchten salzbeeinflussten Standorten 18,9 % und in den Salzmarschen nur 2,6 % gefunden. Pflanzengeographisch wird die untersuchte salzbeeinflusste Vegetation von pantropischen und neotropischen Gattungen dominiert. Im weiteren Sinne neotropische Arten sind vorherrschend, wobei die direkte phytogeographische Umgebung des Chaco eine entscheidende Rolle in der Artenzusammensetzung spielt. Das Lebensformenspektrum und die lokale Verteilung entlang eines Niederschlagsgradienten der vorkommenden Arten im Untersuchungsgebiet wurde mit der vorab vom Verfasser angefertigten Checkliste der Gefäßpflanzen im paraguayischen Chaco verglichen. Sowohl im paraguayischen Chaco insgesamt als auch an den untersuchten salzbeeinflussten Standorten dominieren Phanerophyten, während in den Salzmarschen Hemikryptophyten vorherrschen. In den Salzmarschen wurde anhand originaler Vegetationsaufnahmen eine Abfolge von neun Pflanzengesellschaften unterschieden. Die in den meisten Fällen aus nur einer Differenzialart bestehenden Gesellschaften weisen nur selten allmähliche Übergänge auf und kommen entlang eines Gradienten unterschiedlicher Wasserverfügbarkeit vor. Der Gradient reicht von der hydrohalophilen Ruppia maritima-Gesellschaft und der hygrophilen Setaria geminata-Gesellschaft schwach salziger Standorte bis zur stark salz- und trockenresistenten Heterostachys ritteriana-Gesellschaft. Als signifikante Bodeneigenschaften, die die Verteilung der Arten in den Salzmarschen bestimmen, konnten der Natriumgehalt und die organische Substanz im Oberboden festgestellt werden. Setaria geminata kommt in Böden mit höherem Humusanteil vor, während in natriumreichen Böden Heterostachys ritteriana und Sarcocornia ambigua vorherrschen. Eine bedeutende Rolle spielen außerdem kleine Reliefunterschiede, die maßgeblich die Sedimentablagerungen, Wasserverfügbarkeit und Dauer der Überschwemmung beeinflussen. Sandige Sedimentaufschüttungen reduzieren die Feuchtigkeit und Salinität und erleichtern die Etablierung von Pionierarten, wie Sesuvium portulacastrum und Sporobolus pyramidatus. Die untersuchte salzbeeinflusste Gehölzvegetation konnte anhand originaler Vegetationsaufnahmen in zehn Gesellschaften klassifiziert werden, die entlang eines Wasserverfügbarkeitsgradienten vorkommen. Entlang dieses Gradienten nimmt die Arten- und Strukturdiversität zu und der Anteil an halophilen Arten ab. Die Bodenparameter, die signifikant die Artenzusammensetzung in den Gebüsch- und Waldgesellschaften beeinflussen, sind der Natriumgehalt und die Bodenart. Hohe Natrium- und pH-Werte im Oberboden sind in den untersuchen Probeflächen positiv korreliert und kennzeichnen salzreiche Standorte, die größtenteils von halophilen Arten besiedelt werden. Typische halophile Straucharten sind Cyclolepis genistoides, Lophocarpinia aculeatifolia, Lycium americanum, Lycium boerhaaviaefolium und Prosopis rojasiana. Die Bodenart im Oberboden spielt für die Artenzusammensetzung eine entscheidende Rolle, da hohe Schluff- und Tonanteile im Oberboden zu einer schlechten Dränage und somit zu stauwasserbeeinflussten Habitaten führen. Dieser Effekt kann ganz besonders an Standorten der Parkinsonia aculeata-Copernicia alba-Gesellschaft, der Prosopis ruscifolia-Sporobolus pyramidatus-Gesellschaft, der Prosopis ruscifolia-Evolvulus convolvuloides-Gesellschaft und der Prosopis ruscifolia-Tabebuia nodosa-Gesellschaft beobachtet werden. Anhand von Strukturmessungen aller Stämme mit einem BHD ≥10 cm wurden die Abundanz, Frequenz, Dominanz und der Bedeutungswert-Index (IVI) für alle Gehölzarten in den einzelnen Gesellschaften berechnet. Prosopis ruscifolia erreicht hohe Abundanz- und Frequenzwert in den Gebüschgesellschaften, während Salta triflora ein besonderer Stellenwert in den Waldgesellschaften zukommt. In dieser Arbeit werden die Untersuchungsergebnisse der salzbeeinflussten Vegetation im paraguayischen Chaco mit ähnlichen Studien aus dem südamerikanischen Kontext verglichen und syntaxonomisch eingeordnet. Sowohl die Vegetation der Salzmarschen als auch die Gehölzvegetation kann jeweils in drei unterschiedlichen syntaxonomischen Klassen eingeordnet werden. Abschließend werden die Auswirkungen und Entwicklungsprognosen hinsichtlich klimatischer Veränderungen und des immer stärker werdenden Landnutzungswandels diskutiert und Ansätze für zukünftige Nutzungs- und Naturschutzmaßnahmen sowie für weitere Untersuchungen empfohlen.

Thesis (Ph. D.)--University of North Texas, May, 2007. / Title from title page display. Includes bibliographical references.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Thesis (Ph.D.)--University of Wollongong, School of Biological Sciences. / Typescript. Includes bibliographical references: leaf 161-203.

Made available in DSpace on 2015-03-26T13:53:20Z (GMT). No. of bitstreams: 1 texto completo.pdf: 4718025 bytes, checksum: 1572d41f69f9da99bde64bdd168039a2 (MD5) Previous issue date: 2011-07-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The framework of advanced environmental degradation in the central region of the Rio Doce in the state of Minas Gerais by is attributed several authors to the practice of extensive cattle raising added to interactions with the soil, climate, geomorphology and also anthropic interactions. As an aggravating factor of the degradation in the region, some researchers begin to draw attention to the expansion of mono-dominated fragments by the aroeira forest species (Myracrodruon urundeuva Fr. All.). Parallel to this scenario, M. urundeuva appears in the official list of species of flora threatened with extinction in the category "Vulnerable" from 1992 until the present day. On the other hand the Regulatory Ordinance number 85 of September 26, 1991 of IBAMA allows the exploitation of the species in secondary forests through a forest management plan. It is felt that the lack of knowledge about the mono-dominated fragments by aroeira entails the insecurity of the law operators regarding the authorization for intervention in these environments; this is aimed at the recovery of degraded areas and the sustainable management of these fragments. In the search to clarify questions about the areas under mono-dominance of aroeira, this work aimed to characterize the major floristic composition, the horizontal structure and the parametric structure of forest stands under the mono-dominance of Myracrodruon urundeuva in Tumiritinga-MG; evaluate the existence of correlation between chemical and physical attributes of the soil and the expansion of settlements mono-dominated by the aroeira; evaluate the performance of the maximum likelihood classifier and the classifier of artificial neural networks to map the areas occupied by fragments of aroeira in mono-dominance in the city of Tumiritinga-MG; and evaluate the potential use of remote sensing data on board the Landsat TM-5 and RapidEye satellites for the mapping of the areas mono-dominated by aroeira. For this the city of Tumiritinga was widely covered by registering with a GPS navigation device and photo the forms of land use prevalent throughout the studied region. Sixteen inventory plots of forest were distributed throughout the city representing the diversity of environments where the Aroeirais manifest. In the plots inventory xi circles, the total height and botanical identification of all individuals with CAP> 15.7 cm were recorded. From the collected data it was made an analysis of horizontal structure, parametric structure and floristic of the fragments mono-dominated by aroeira in the city of Tumiritinga using the Mata Nativa 2.0 software. In eleven of the sixteen parts of inventory, three undisturbed samples composed of soil were collected and three simple disturbed samples of soil were collected randomly. For each plot it was selected an adjacent pasture from where three simple undisturbed soil samples were collected and three deformed soil samples composed of soil, totaling 33 samples of soil under "Aroeirais" and 33 samples of soil under pasture. The soil samples were submitted to the following chemical analysis: pH in H2O; levels of Ca2+, Mg2+, K+, Al3+, exchangeable Na+, available P, H + Al, SB, t, T, V, m; MOS and ISNa, and the following physical tests: texture, Dp, Ds, Pt, Pmic, Pmac, Ko and water retention at field capacity (-10 kPa) at the permanent wilting point (- 1500 kPa) and in tensions equivalent to -300 kPa and -500 kPa. In order to evaluate the hypothesis of equality between the averages of chemical and physical parameters obtained in mono-dominance of aroeira and grazing systems, it was applied the t test for independent samples, at 5% of significance. For classification of the RapidEye image two methods of supervised classification were evaluated: the classification by the maximum likelihood algorithm and the classification by Artificial Neural Networks. We tested 19 combinations involving bands, principal components and the normalized difference of vegetation index (NDVI). The network training was carried out by trial and error. For the classification of the Landsat image, the maximum likelihood algorithm was used and tests were made with 10 combinations involving bands, principal components and NDVI. The assessment of the thematic maps that were produced was performed using the Kappa and conditional Kappa coefficients for the class of aroeira soil use. The horizontal structure and the floristic analysis of forest fragments inventoried in the city of Tumiritinga-MG prove the monodominant occurrence of M. urundeuva in the study region. The monodominance of aroeira is characterized by low diversity of species and dominance reflected in 96% of individuals that were sampled, 96% of the baseline measure and 96% of the total amount of stored wood. The chemical parameters K+, Ca2+, Mg2+, SB, T and t differed significantly between the grazing systems and aroeira monodominance, the values of all parameters in the aroeira monodominance system were superior. The physical parameters Dp, Pmic, Pt and silt content differed significantly between the grazing systems and aroeira monodominance; the values of Dp, Pmic and Ptot higher in soils under aroeira monodominance and silt content were superior in the upper pasture. The best results were found for the classification of the RapidEye image was obtained by the maximum likelihood algorithm that showed a kappa coefficient equal to 80 and 90 for conditional Kappa. For the Landsat image the Kappa and conditional Kappa coefficients for the aroeira class were respectively 80 and 76. Through the thematic maps produced it was observed that 22% of the city of Tumiritinga, 10,758 ha, is under the occupation of the aroeira in monodominance. Given the size that the settlements monodominated by aroeira occupy in the landscape, the implications of the aroeira monodominance imposes on the biodiversity in soil conservation, and in the sustainability in the local agroecosystem, it is necessary to pursue further studies in order to clarify the edaphic and ecological mechanisms involved in the maintenance and expansion of areas monodominated by aroeira. The knowledge of the conditioning processes of this system may help the development of plans for sustainable forest management; in which the combination the timber and not timber production will be able to increase the productivity and the income of farmers. / O quadro de avançada degradação ambiental na região do médio rio Doce mineiro é atribuído por diversos autores à prática da pecuária extensiva somada às interações edáficas, climáticas, geomorfológicas e antrópicas. Como agravante da degradação na região, alguns pesquisadores começar a chamam a atenção para a expansão de fragmentos monodominados pela espécie florestal aroeira (Myracrodruon urundeuva Fr. All.). Paralelo ao quadro de expansão de áreas monodominadas pela aroeira no médio Rio Doce, a espécie aparece na lista oficial de espécies da flora brasileira ameaçada de extinção na categoria vulnerável desde 1992 até o presente. Em contrapartida a Portaria Normativa n° 83 de 26 de setembro de 1991 do IBAMA, permite a exploração da espécie em florestas secundárias, mediante plano de manejo florestal. Percebe-se que a falta de conhecimento sobre os fragmentos monodominados por aroeira acarreta na insegurança dos operadores do direito no que tange a autorização de intervenção nestes ambientes, seja esta visando a recuperação de áreas degradadas ou o manejo sustentável destes fragmentos. Na busca de elucidar algumas questões sobre as áreas sob monodominância de aroeira, este trabalho teve por objetivos principais caracterizar a composição florística, a estrutura horizontal e a estrutura paramétrica de povoamentos florestais sob monodominância de Myracrodruon urundeuva em Tumiritinga-MG; avaliar a existência de correlação entre atributos químicos e físicos do solo e a expansão de povoamentos monodominados pela aroeira; avaliar o desempenho do classificador da maximaverossimilhança e do classificador de redes neurais artificiais para mapear áreas ocupadas por fragmentos de aroeira em monodominância no município de Tumiritinga-MG; e avaliar o potencial de uso de dados de sensores remotos a bordo dos satélites Landsat TM-5 e Rapideye para o mapeamento de áreas monodominadas por aroeira. Para tanto o município de Tumiritinga foi amplamente percorrido, registrando com aparelho GPS de navegação e fotografias as formas de uso do solo predominantes no município, em especial os aroeirais . Dezesseis parcelas de inventário florestal foram distribuídas ao longo do município representando a diversidade de ambientes onde os aroeirais se manifestam. Nas parcelas de inventário foram registradas as circunferências, a altura total e a identificação botânica de todos os indivíduos com CAP > 15,7 cm. A partir dos dados foram feitas as análises de estrutura horizontal, estrutura paramétrica e florística dos fragmentos monodominados por aroeira no município de Tumiritinga utilizando o software Mata Nativa 2.0. Em onze das dezesseis parcelas de inventário, três amostras indeformadas compostas de solo foram coletadas e três amostras deformadas simples de solo foram coletadas de forma aleatória dentro das parcelas. Para cada fragmento foi selecionado uma pastagem adjacente de onde foram coletadas três amostras indeformadas simples de solo e três amostras deformadas compostas de solo, totalizando 33 amostras de solo sob aroeirais e 33 amostras de solo sob pastagens. A partir das amostras de solos foram realizadas as seguintes análises químicas: pH em H2O; teores de Ca2+, Mg2+, K+, Al3+, Na+ trocáveis; P disponível; H + Al; SB; t; T; V; m; MOS e ISNa; e as seguintes análises físicas: textura, Dp, Ds, Pt, Pmic, Pmac, Ko e retenção de água na capacidade de campo (-10 kPa) no ponto de murcha permanente (-1.500 kPa) e nas tensões equivalentes de -300 kPa e -500 kPa. Para avaliar a hipótese de igualdade entre as médias dos parâmetros químicos e físicos obtidos nos sistemas de monodominância de aroeira e de pastagem, foi aplicado o teste t para amostras independentes, a 5% de significância. Para a classificação da imagem Rapideye foram avaliados dois métodos de classificação supervisionada, a classificação pelo algoritmo da maximaverossimilhança e a classificação por Redes Neurais Artificiais. Foram testadas 19 combinações envolvendo bandas, componentes principais e o índice de vegetação da diferença normalizada (NDVI). O treinamento da rede foi realizado por tentativa e erro. Para a classificação da imagem Landsat foi utilizado o algoritmo da máximaverossimilhança e foram testadas 10 combinações envolvendo bandas, componentes principais e o NDVI. A avaliação dos mapas temáticos produzidos foi realizada através dos coeficientes Kappa e Kappa condicional para a classe de uso do solo aroeira . A estrutura horizontal e a análise florística de fragmentos florestais inventariados no município de Tumiritinga MG comprovam a ocorrência monodominante da espécie florestal aroeira (Myracrodruon urundeuva Fr. All) na região de estudo. A monodominância de aroeira é caracterizada por baixa diversidade de espécies e dominância refletida em 96% dos indivíduos amostrados, 96% da área basal medida e 96% do volume total de madeira estocado. Os parâmetros químicos K+, Ca2+, Mg2+, SB, T e t diferiram significativamente entre os sistemas pastagem e monodominância de aroeira, sendo os valores de todos os parâmetros superiores no sistema monodominância de aroeira. Os parâmetros físicos Dp, Pmic, Pt e teor de silte diferiram significativamente entre os sistemas pastagem e monodominância de aroeira, sendo os valores de Dp, Pmic e Ptot maiores em solos sob monodominância de aroeira e o teor de silte superior nas pastagens. O melhor resultado encontrado para a classificação da imagem Rapideye foi obtido pelo algoritmo da maximaverossimilhança que apresentou coeficiente Kappa igual a 80 e Kappa condicional 90. Para a imagem Landsat os coeficientes Kappa e Kappa condicional para a classe Aroeira foram respectivamente 80 e 76. Através dos mapas temáticos produzidos observou-se que 22% do município de Tumiritinga, 10.6758 ha, se encontra sob ocupação da aroeira em monodominância. Dado a dimensão que os povoamentos monodominados por aroeira ocupam na paisagem, as implicações que a monodominância da aroeira impõe sobre a biodiversidade, sob a conservação dos solos, e sob a sustentabilidade dos agroecossistemas locais, fazem-se necessários estudos complementares que busquem esclarecer os mecanismos edáficos e ecológicos envolvidos na manutenção e expansão das áreas monodominadas por aroeira. O conhecimento dos processos condicionantes deste sistema poderá subsidiar a elaboração de planos de manejo florestal sustentável que, conciliando a produção madeireira e não madeireira sejam capazes de aumentar a produtividade e a renda do produtor rural.

Orientador: Carlos Alfredo Joly / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-10T10:40:29Z (GMT). No. of bitstreams: 1 Campos_MarianaCruzRodriguesde_M.pdf: 1163778 bytes, checksum: 23afceb268de73a302a57bd5f98b98c4 (MD5) Previous issue date: 2008 / Resumo: Em uma parcela de um hectare dividida em 100 subparcelas de 10 x 10 m foram plaqueados todos os indivíduos arbóreos com no mínimo 15 cm de perímetro a altura do peito (DAP = 4,8 cm), e suas alturas foram estimadas e o perímetro medido. Todas as subparcelas tiveram a cobertura por rochas maiores que 50 cm de diâmetro estimada em cinco classes de freqüência, e foram anotados os indivíduos que crescem diretamente sobre as rochas. Analises de concentração de elementos químicos no solo foram feitas para 16 subparcelas e interpoladas para as demais por gridding. As relações entre a composição e estrutura de um trecho de Floresta Ombrofila Densa Atlântica e variáveis microtopograficas e edaficas foram analisadas através de Analise Canonica de Correspondência (CCA), uma analise multivariada de ordenação. Foram encontradas 1274 arvores dentro do critério amostral, pertencentes a 41 famílias botânicas (com destaque para Myrtaceae, Rubiaceae e Fabaceae) e 142 espécies ou morfotipos. As espécies mais importantes (IVI) sao: Euterpe edulis, Mollinedia schottiana, Bathysa mendoncaei, Coussarea accedens, Rustia formosa e Guapira opposita. O indice de diversidade de Shannon foi de 4,05nats/ind e de equabilidade de Pielou, de 0,82. A altura media das arvores e de nove metros, e o dossel esta a cerca de 18 m. O diâmetro médio dos individuos e de 13,9 cm, e 29 indivíduos ultrapassam os 50 cm DAP. A área basal somada do hectare e de 30,27 m2 (arvores vivas). Foi encontrada uma relação direta entre a cobertura por rochas e menor riqueza de espécies e numero de indivíduos por subparcela. Nenhuma relação foi encontrada entre os afloramentos rochosos e a altura media e diâmetro médio nas subparcelas. 34 espécies arbóreas nesta área amostral são capazes de crescer sobre rochas; 11 delas sem lancar raízes para o solo, com destaque para Euterpe edulis e Guapira opposita. A altura e diametro dos indivíduos que crescem sobre rochas não difere estatisticamente do restante dos indivíduos da parcela. A ordenação (CCA) da comunidade sugere que os fatores ambientais que mais influenciam a variação de parâmetros fitossociologicos são a quantidade de rochas afloradas e a inclinação do terreno. A segunda CCA (realizada com espécies que possuem 10 ou mais indivíduos amostrados) nao possui valores altos de inércia, alem dos resultados possuírem chance maior que 20% de serem produzidos ao acaso. No entanto, as variáveis apontadas como de maior importância para os vetores; afloramentos rochosos e de água, concentração de Al, P e pH são consistentes com demais estudos em florestas tropicais / Abstract: In a 1-ha plot divided into 100 subplots of 10 x 10 m, all trees with at least 15 cm of perimeter at breast height (DBH = 4.8 cm) were marked and had their heights estimated and perimeter taken. The rock cover (rocks over 50 cm diameter) was estimated in fie classes of frequency, and records were made for individuals growing directly on rocks. The concentration of soil chemical elements was analysed for 16 subplots and the results were interpolated by gridding methods for the other subplots. The relations between the composition and structure of a patch of Atlantic Ombrofilous Dense Forest and the microtopographical and edaphic variables were analyzes through Canonical Correspondence Analysis (CCA), a multivariate ordination analysis. 1274 trees in the sampling criteria were found, belonging to 41 botanical families (highlighting Myrtaceae, Rubiaceae and Fabaceae) and 142 species or morphotypes. The most important (Importance Value Index) species are: Euterpe edulis, Mollinedia schottiana, Bathysa mendoncaei, Coussarea accedens, Rustia formosa and Guapira opposita. Shannon¿s diversity index was 4.05nats/ind and Pielou¿s equability was 0.82. The average tree height is of nine m and the canopy is at around 18 m. The trees¿ average diameter is 13.9 cm, and 29 individuals surpass 50 cm DBH. The basal area for the 1-ha plot (live trees only) is 30.27m2. A direct relation was found between rock cover and lesser species richness and stem number per subplot. No relation was found in regard to rocks and average height and DBH. 34 tree species in this area are able to grow on rocks; 11 of which don¿t grow roots to the soil, particularly Euterpe edulis and Guapira opposita. The height and diameter of the individuals that grow on rocks is not statistically different from the remaining in the plot. The CCA for the community suggests that the environmental factors that influence phytosociological parameters the most are the amount of rocks and the slope. The second CCA (performed with species with 10 or more individuals) does not have high inertia values, and there is also at least 20% probability t hat the results could be obtained by chance. However, the variables shown as of major importance for the vectors (surfaced water and rocks, Al and O concentration and pH) are consistent with other studies in tropical rainforests / Mestrado / Biologia Vegetal / Mestre em Biologia Vegetal

Orientador: Fernando Roberto Martins / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-16T17:11:12Z (GMT). No. of bitstreams: 1 Iguatemy_MarianadeAndrade_M.pdf: 2722177 bytes, checksum: 71fd77f89fecb80cd377713f0b2887fc (MD5) Previous issue date: 2008 / Resumo: A fragmentação florestal tem como principal origem o desmatamento. Dentre suas conseqüências, os efeitos de borda se destacam. Na Mata Atlântica essa situação é grave, pois este domínio, reduzido a 7% de sua cobertura original, vem sofrendo grande pressão antrópica. Nesse cenário, esteestudo avaliou os efeitos de borda sobre a dinâmica da estrutura da comunidade de plântulas na Mata Atlântica da Reserva Biológica União-RJ. Foram realizadas comparações entre as comunidades de plântulas localizadas em bordas artificiais, formadas por dois corredores desmatados, Rede Elétrica e Gasoduto, em contraste com o Interior a mais de 400 m de qualquer borda. Plots permanentes 2x1 m foram alocados, de forma aleatória estratificada dentro de cada parcela de 20x 50 m, sendo que em cada localidade foram estabelecidas 4 parcelas em distintos sítios. Nos plots todas as plântulas foram etiquetadas e medidas (altura, diâmetro a altura do solo) a partir do ano 2000 e nos anos subseqüentes (2001, 2004, 2005). Foi observada sazonalidade de alguns eventos no banco de plântulas nas diferentes estações do ano (seca e chuvosa) em todas as localidades. Interior apresentou maior densidade e dinâmica, marcada pelos altos valores de mortalidade e recrutamento durante todo o intervalo de estudo. As bordas florestais foram mais susceptíveis a danos marcadas por altos valores de rebrotos e a ocorrência de espécies exóticas (Artocarpus heterophyllus Lam.). Além disso, foram encontradas maiores taxas de crescimento e alta heterogeneidade das variáveis e parâmetros estudados nestes locais. Gasoduto influenciou mais a comunidade de plântulas, pois apresentou redução de densidade ao longo de todo estudo. Portanto, os resultados observados sugerem que a comunidade está submetida a efeitos de borda, em que intensidade e forma podem variar ao longo do tempo. Uma vez que não houve um tamponamento destes efeitos, isto pode indicar que a manutenção dos limites artificiais perpetua localmente os efeitos de borda sobre plântulas na Reserva Biológica União / Abstract: The forest fragmentation has as main cause the deforestation. Among its consequences, the edge effects are the most prominent ones. In the Atlantic Rain forest, this situation is even more serious since this Ecosystem is reduced to 7% of its original coverage, and it has been suffering from intense human pressure. In this scenery, this study evaluated the edge effects on the dynamics of the seedling community structure at a Biological Reserve called: Reserva Biológica União-RJ. Comparisons were made between seedling communities located in artificial edges formed by two deforested corridors: power line and gas duct, in contrast with the interior of the forest, located at 400m from any edge. Permanent plots having 2x1m were placed in a stratified random manner within each 20x50m parcel. These parcels where evenly distributed between the localities, which had four parcels in each. Within the plots, all seedlings were tagged and measured (tall and stem diameter in base), from year 2000 to subsequent years (2001, 2004, 2005). It was observed seasonality of some events in the seedling bank on different seasons of the year (dry and rainy) in all localities. Interior presented higher seedling density and dynamics, due to high values of mortality and recruitment during the whole interval of the study. The forest edges were more susceptive to damage, due to high values of resprouting and the invasion of exotic species (Artocarpus heterophyllus Lam.). Moreover, it was found a major seedling growth and a high heterogeneity of the variables and parameters studied in these locations. Gas duct influenced the seedlings community more, because it presented a density reduction during all the study. Therefore, all observed results suggest that the seedling community is subjected to the edge effects, so that intensity and form can present a variation over time. Since there wasn¿t a neutralization of these effects, the results also indicate that the maintenance of artificial limits (GA and RE) locally perpetuate the edge effects on the seedlings of the Biological Reserve / Mestrado / Biologia Vegetal / Mestre em Biologia Vegetal

Orientadores: Kikyo Yamamoto, George John Shepherd / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-15T02:40:57Z (GMT). No. of bitstreams: 1 Bertoncello_Ricardo_M.pdf: 8895754 bytes, checksum: 5b50a52fbb7e96dfd8126d57935601cf (MD5) Previous issue date: 2009 / Resumo: A classificação e a delimitação das diferentes formações fitogeográficas que ocorrem no domínio da Mata Atlântica nas regiões Sul e Sudeste do Brasil constituem um desafio para botânicos, ecólogos e fitogeógrafos. A distribuição atual destas formações está relacionada ao histórico de ocupação das áreas e a complexos gradientes ambientais, que ocorrem nos sentidos horizontal (latitudinal, longitudinal e edáfico) e vertical (altitudinal). Visando a contribuir para o conhecimento das formações florestais que integram a Mata Atlântica, este trabalho foi realizado no Morro do Cuscuzeiro (Ubatuba-SP) com os objetivos de: (1) descrever as variações florísticas e estruturais nas comunidades arbóreas em função da altitude, e verificar se existe uma Floresta Nebular que possa ser discriminada por parâmetros florísticos e estruturais; e (2) verificar a situação fitogeográfica das comunidades encontradas neste local no contexto da Mata Atlântica nas regiões Sul e Sudeste do Brasil. O Morro do Cuscuzeiro se situa no Núcleo Picinguaba do Parque Estadual da Serra do Mar (23° 18' 14" S e 44° 47' 16" W) e possui 1277m de altitude. O gradiente altitudinal foi representado por amostras de quatro cotas altimétricas, 820m, 970m, 1120m e 1270m, obtidas em 10 parcelas de 10 x 10 m em cada cota, exceto na mais alta que foi dividida em duas 'sub-cotas' com 5 parcelas cada. O critério de inclusão amostral da flora arbórea foi de 15 cm de CAP (exceto nas duas 'sub-cotas' superiores, 10 cm de CAP). Em sentido base-topo, foi verificada diminuição na riqueza, na diversidade, na altura, no diâmetro e no volume das árvores, e aumento na densidade. Uma mudança abrupta na composição da comunidade arbórea foi detectada a 1120m, acima da qual aparece uma formação que identificamos como Floresta Nebular, em substituição à floresta de encosta da Serra do Mar, que ocorre abaixo daquela altitude. As espécies destas duas formações florestais foram inseridas em uma matriz de 1546 espécies registradas em 112 levantamentos de 78 localidades do domínio da Mata Atlântica nas regiões Sul e Sudeste do Brasil. As análises multivariadas resultaram em cinco grupos de levantamentos: 1-Florestas Nebulares; 2- Florestas da província costeira (posteriormente sub-dividido em (a) Florestas de encosta e (b) Florestas de topo de morro e florestas da planície costeira); 3-Florestas de Araucária; 4-Florestas Semi-decíduas; e 5- Florestas Semi-decíduas Montanas. As formações encontradas no Morro do Cuscuzeiro foram incluídas nos grupos das Florestas Nebulares (de 1120m e 1270m) e das florestas de encosta da província costeira (820m e 970m), o que reforçou os resultados da análise dos dados locais, mostrando que pequenas diferenças em altitude podem resultar em mudança abrupta na composição das comunidades, evidenciada pela presença de espécies de distribuição disjunta que são compartilhadas com outras formações de Florestas Nebulares das regiões Sul e Sudeste do país / Abstract: The classification and delimitation of different vegetational formations into a phytogeographic system in Brazil has been a challenge to ecologists, botanists, and phytogeographers. The current distribution of these formations is related to historical process of land use and complex environment gradients, occurring in horizontal (latitude, longitude and edafic) and vertical (altitude) ways. The aims of this study were (a) to describe the changes in floristic composition and structure of tree species along an elevational gradient on Morro do Cuscuzeiro, Ubatuba (SP), and to verify the occurrence of a Cloud Forest that can be discriminated by floristic and structural paremeters; and (b) to analyze the phytogeographic position of the communities found in this mountain in relation to other surveys of the Atlantic Rain Forest domain in Southern and Southeastern Brazil. Mountain Cuscuzeiro is located in the Serra do Mar State Park (at 23° 18' 14" S, 44° 47' 16" W it is 1277m in height). A survey of tree species was made in four elevational levels, 820m, 970m, 1120m, and 1270m, using 10 samples of 10x10m on each level, except on the higher one, which was sub-divided in two sub-levels whith five samples on each. The sampling criterion was 4,8cm of DBH (except in the two higher sub-levels, where 3,2cm of DBH was used). The analysis resulted in consistent groups at the different levels, indicating a strong altitude influence on the floristic composition. An abrupt change of the vegetation was identified at 1120m, from where a typical Ombrophilous Dense Forest (slope forest from 820m to 970m) shifted into a Cloud Forest formation (1120m to 1270m). These two formations were inserted in a matrix made by a total of 1546 species of 112 surveys from 78 locations of Atlantic Rain Forest domain in southern and southeastern Brazil. The multivariate analysis resulted in five groups of samples: 1- The Cloud Forest; 2- The coastal province (further subdivided into (a) the slope forests and (b) a subgroup composeded by the mountaintop and the coastal plain forests); 3- The Araucaria Forest; 4-The Semi-Deciduous Forest; and 5- The Montane Semi-Deciduous Forest. The formations found on Mt. Cuscuzeiro were included in the groups of the Cloud Forest (from 1120m to 1270m) and of the Coastal Province (from 820m to 970m), which reinforced the results of the local elevational gradient analysis, showing that minor changes on altitude can lead to abrupt changes in community composition due to the occurrence of species with disjunct distribution that are shared with other Cloud Forest formations of southern and southeastern Brazil / Mestrado / Biologia Vegetal / Mestre em Biologia Vegetal