Management and restoration of black oak dominated sand savannas often rely on historic vegetative descriptions (settler accounts, surveyor notes, aerial photographs). It is commonly assumed that fire alone maintains savanna structure and composition, however little information is known about the specific fire frequency needed to maintain these systems. The objective of this study was to quantify and correlate characteristics of stand structure with fire history of the Kankakee Sands savannas in northeastern Illinois. Fire history chronologies were determined through dendrochronological methods from 289 dated fire scars identified on 58 black oak (Quercus velutina) trees located throughout four wooded sites. Tree and woody structure was characterized in 30 circular plots (0.04 hectares) in three sites and 26 circular plots in one site that were placed at 25-meter intervals along randomly established permanent line transects in the summer of 2007. The structure analysis consisted of the development of tree age-size relationships among presently dominant and suppressed trees in relation to fire history. Variations in tree and woody structure were strongly related to fire dynamics among the four study sites. Specifically, components such as tree density (n = 114; r = 0.46; P < 0.0001), basal area (n = 114; r = 0.35; P < 0.0001), and total woody stem density (n = 114; r = 0.42; P < 0.0001) all increased as a function of fire-free interval. In addition, sites with shorter fire-free intervals were associated with a higher percentage of hollow tree boles (n = 104 r = -0.31 P < 0.0015) and visible fire scar wounds (n = 104 r = -0.43334 P < 0.0001). While the results of this study suggest fire had a significant role in structuring these four wooded sites, the data also indicated other historic disturbances coupled with individual site characteristics may be integral components in structuring these dynamic systems. For instance, fire-free intervals less than two years maintained conditions of openness, as was referenced to 1939 historic aerial photographs, but eliminated potential future canopy trees. Under these conditions, a dramatic shift in community structure toward prairie vegetation is likely, as no smaller trees were present to assume canopy dominance. Fire-free intervals greater than two years were associated with transition to closed canopy forests. Therefore, management considerations pertaining to fire with the addition of other historic disturbances, including grazing and or selective cutting, are proposed to balance historic canopy openness and promote regeneration of characteristic savanna species.

Sea-level rise and stronger hurricanes associated with global climate change will likely result in farther reaching storm surges that will greatly affect coastal ecosystems. These surges can transport nutrients, salt water, and sediment to nutrient poor, fresh (i.e. low salinity) pine savannas. Purple pitcher plants (Sarracenia purpurea ) are pine savanna inhabitants that could potentially be at a disadvantage because their pitcher morphology and stout structure may leave them prone to collecting saline water and sediment after a surge. In this study, separate field and greenhouse experiments were conducted to test the effects of storm surge water salinity and sediment type on pine savanna soil characteristics, plant community structure, and pitcher plant vitality. In the field, plots (containing &ge genet of S. purpurea ) were experimentally storm surged with fresh or saline water crossed with one of four sediment types (local, foreign, fertilized foreign, or no sediment). Saline water inundation resulted in significantly higher pitcher plant mortality than the fresh water treatment combinations. However, a subsequent prescribed fire and regional drought affected the study area during the next growing season, resulting in the decline of all the pitcher plants to zero or near zero percent cover. Soil data revealed that the combination of salt water and fertilized sediment resulted in short-term increases in soil-water conductivity and nitrogen availability. Interestingly, there were no significant differences in plant community structure between treatments, suggesting that the community as a whole is not as vulnerable as the pitcher plants to the cumulative effects of multiple stressors (i.e. storm surge, fire, and drought) operating in this system. Indicator species analysis revealed that some species were significant indicators of certain treatments; thus suggesting that pitcher plants are not the only species affected by storm surge. In the greenhouse, pitcher plants received various forms of sediment (i.e. no sediment, sterile sediment, or one of two levels of fertilized sediment) within their pitchers to determine if nutrient uptake is either inhibited or enhanced. Plants that received sterile sediment had higher carbon:nitrogen ratios and higher leaf mass per unit area. Eutrophic sediment deposition resulted in a temporary decrease in relative growth rate as well as changes in pitcher morphology. There were no differences in chlorophyll content and photosynthetic rates between treatments. Both the field and greenhouse experiments indicate that global climate change may indirectly contribute to the further decline of southeastern purple pitcher plant populations in the future.

Wet pine savannas are among the most diverse ecosystems in North America and provide critical habitat for many species but have seen a dramatic decline in size over the past century due to urbanization, logging, and fire suppression. Coastal pine savannas are also vulnerable to anticipated effects of global climate change. Models of climate change predict rapid sea-level rise along the northern Gulf of Mexico and more intense hurricanes. Restoration of these fragile wetland ecosystems is needed, but the effects of climate change on restored, as well as remnant communities, are unknown. This research aimed to compare resiliency of remnant and restored plant communities to simulated hurricane disturbance. I hypothesized that species composition within both site types will be altered following experimental storm surge, and restored plots will follow a different compositional trajectory due to site conditions including invasion by non-target species and disturbed soils. I compared community composition and soil properties between remnant and restored sites experiencing experimental storm surge. Non-metric multidimensional scaling (NMDS) ordinations and a cluster analysis was used to visualize dissimilarities in composition and permutational analysis of similarity (PERMANOVA) was used to compare composition among treatment, site, and time. Repeated measure analysis of variance (ANOVA) was used to compare soil water conductivity and available ammonium over the course of the study. Results from compositional surveys suggested no significant effect of treatment on community composition, but there were significant vectors for soil moisture and ammonium resulting in different compositional trends and an apparent degree of divergence over time between the two site types. Soil characteristics (texture and bulk density) and pressure from neighboring plants within the restored site are also likely contributing to differences between the two site types. As climate change continues to alter disturbance regimes that shape coastal ecosystems, it will be necessary to assess structure and function of remnant and potentially novel plant communities and their capacity for adaptation.

Made available in DSpace on 2014-06-11T19:35:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-05-05Bitstream added on 2014-06-13T20:46:29Z : No. of bitstreams: 1 maeda_as_dr_ilha.pdf: 627520 bytes, checksum: 3ca12dcf10a4db4ea5c75fbae37bd02e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A adubação representa cerca de 20% dos custos de produção da cana-de-açúcar e entre os nutrientes utilizados, o potássio constitui o elemento mais exigido pela cultura, juntamente com o nitrogênio. O trabalho teve como objetivo estudar os efeitos de doses de nitrogênio e de potássio na produtividade e qualidade das socas de cana-de-açúcar no 3º e 4º ciclos e no 4º ciclo em áreas com palhada (CCP) e sem palhada (CSP) sobre o solo. Os experimentos com os 3º e 4º ciclos foram conduzidos nos anos de 2006 a 2008 com a variedade RB 83-5486 na fazenda Vale da Pecuária, município de Selvíria-MS, e os experimentos com 4º ciclo da cana- de-açúcar em áreas com e sem palhada sobre o solo foram conduzidos nos anos de 2007 a 2008 com variedade RB 86-7515 nas fazendas A Raimundo e Retiro II, respectivamente, no município de Aparecida do Taboado-MS. Todos os experimentos foram desenvolvidos em áreas administradas pela Usina Alcoolvale S/A com quatro doses de nitrogênio (40, 80, 120 e 160 kg ha-1 de N), na forma de uréia, e quatro doses de potássio (40, 80, 120 e 160 kg ha-1 de K2O), na forma de cloreto de potássio, em um esquema fatorial 4x4, totalizando 16 tratamentos dispostos em blocos ao acaso, com quatro repetições. Foram avaliados os teores foliares de macronutrientes nas folhas e nos colmos, açúcares redutores do caldo e da cana, pol do caldo e da cana, pureza do caldo, brix, fibra, produtividade agroindustrial, produção de matéria-seca e produtividade de colmos. Para os experimentos 3º e 4º ciclos da cana-de- açúcar com a variedade RB 83-5486 as doses de N e de K aumentaram os teores de macronutrientes na folha e no colmo. Para os indicadores de qualidade da cana-de-açúcar, houve apenas efeito das doses de N no teor de brix no 3º ciclo, evidenciando que a matéria- prima estava com boa qualidade tecnológica e dentro... / The fertilization represents around 20% of the production cost of sugar-cane crop and potassium constitutes its most demanded nutrient, together with nitrogen. The study had the objective of evaluating the effects of nitrogen and potassium rates on 3th and subsequent 4th cycle of sugar-cane crop (ratoon), and on 4th cycle of this crop in areas with or without cane trash burning, on its productivity and quality. The experiments of 3th and 4th cycles were conducted from 2006 to 2008 with the RB 83-5486 variety at Vale da Pecuária farm, Selvíria- MS, and the experiments with 4th cycle of the sugar-cane in areas managed with (+TB) or without (-TB) cane trash burning were conducted from 2007 to 2008 with variety RB 86-7515 at A Raimundo and Retiro II, respectively, in Aparecida do Taboado-MS. All experiments were carried out in areas administered by Usina Alcoolvale S/A, in a randomized block design using a 4x4 factorial scheme, with four rates of nitrogen (40, 80, 120 and 160 kg ha-1), as urea and four of potassium (40, 80, 120 and 160 kg ha-1 of K2O), as potassium chloride, totalizing 16 treatments with four replicates. The macro and micronutrients content in leaf and stem, reducing sugars, pol, purity, Brix, fiber content, tillering number in 10 meters, agro industrial productivity, dry matter and cane productivity were evaluated. For the experiments of 3th and 4th cycles N and K rates increased the leaf and stem macro and micronutrients contents. For the quality indicators, there was effect of N rates only on Brix in the 3th cycle, observing that the raw material had good technological quality and within the adequate patterns. The K rates increased the agro industrial productivity, dry matter and cane productivity only for the 4th cycle. The cane yield increased linearly with K rates. For the experiments of 4th cycle with RB 86-7515, the N and K rates increased... (Complete abstract click electronic access below)

O Cerrado é o bioma brasileiro que mais perdeu área para o agronegócio em anos recentes, verificando que a expansão da fronteira agrícola sobre o Cerrado provocou a pulverização dos remanescentes em fragmentos cada vez menores, imersos em matrizes de baixa similaridade, causando uma série de impactos negativos sobre o ecossistema natural. A fragmentação de habitats é considerada uma das mais graves ameaças à conservação da biodiversidade, com consequências ecológicas variáveis, intensificadas na faixa de transição entre matriz e fragmento. Os efeitos de borda são decorrentes de mudanças físicas e bióticas nas faixas marginais das ilhas de vegetação natural, que promovem modificações nas características microclimáticas, as quais conduzem a uma série de alterações importantes nas comunidades que compõem os ecossistemas. O objetivo deste estudo foi investigar a existência de efeito de borda e suas consequências sobre a comunidade vegetal do Cerrado stricto sensu. O estudo foi realizado em fragmento de Cerrado com área de 980,8 ha, localizado no município de Iaras, SP, cujo entorno foi ocupado por pastagem durante cerca de um século. Efetuou-se a caracterização estrutural e florística de diferentes estratos da vegetação em diferentes distâncias da borda (0, 10, 20, 40, 80 m) e coletaram-se dados microclimáticos na matriz (a 10 m de distância da borda) e no interior do fragmento, nas diferentes distâncias da borda e em duas estações do ano (seca e chuvosa). Investigou-se a existência de um possível gradiente de estrutura ou composição da vegetação relacionado com a distância da borda e com as variáveis microclimáticas. Os resultados obtidos mostraram não existir variações de microclima e de estrutura e composição do componente arbóreo e herbáceo-arbustivo em relação à distância da borda do fragmento. Embora independente do microclima e, portanto, diferente dos clássicos efeitos de borda, a invasão pela braquiária (Urochloa decumbens) foi detectada como a única consequência da exposição da periferia do Cerrado stricto sensu às pressões da matriz, causando exclusão das gramíneas nativas e inibindo o desenvolvimento de plantas lenhosas de pequeno porte. A ausência de efeito de borda sobre os demais componentes da vegetação sugere, em um primeiro momento, que esta não é uma ameaça importante para a conservação do cerrado. Porém, a invasão biológica pela gramínea africana é relativamente recente (foi introduzida há cerca de três décadas na propriedade) e suas consequências ainda não podem ser avaliadas adequadamente. É possível que seus impactos sobre os estratos superiores da vegetação venham a ser observados no futuro, quando a inibição da regeneração das espécies arbustivas e arbóreas comprometer a dinâmica da comunidade vegetal e a substituição dos adultos nas populações dessas espécies. Além disso, hoje a invasão só causa impactos significativos sobre a faixa de 0 a 20 m de distância da borda, mas não é possível prever se a gramínea invasora vai se expandir rumo ao núcleo do fragmento no futuro. / From the Brazilian biomes, the Cerrado has been the most widely and rapidly converted to agribusiness in recent years. The expansion of agricultural frontier over the Cerrado domain resulted in thousands of small fragments embedded in matrices of low similarity, causing a series of negative impacts on the natural ecosystem. Habitat fragmentation is considered one of the most serious threats to the conservation of biodiversity and ecological consequences vary, being intensified in the range of transition between matrix and fragment. The edge effects are caused by biotic and physical changes in marginal areas of the islands of natural vegetation, promoting changes in microclimatic characteristics, which leads to a series of important changes in the ecosystems. The aim of this study was to investigate the existence of edge effect and their consequences on the plant community of Cerrado sensu stricto. The study was conducted in Cerrado fragment with an area of 980.8 ha, located in the municipality of Iaras, SP, whose surrounding area was occupied by pasture for about a century. Structure and floristic composition of distinct vegetation layers was assessed at different distances from the edge (0, 10, 20, 40 and 80 m). Climatic data were collected in two seasons (dry and wet), at the same distances withing the fragment and also in the matrix (10 m away from the edge). The existence of a gradient of vegetation composition or structure and the microclimatic variables related to distance from the edge was investigated. No changes in microclimate and structure or composition of the wood layers related to distance from the edge was observed. Although independent of the microclimate and therefore different from classic edge effects, invasion by the African grass Urochloa decumbens (braquiária) was detected as the only consequence of exposure of the periphery of the cerrado sensu stricto to the pressures of the matrix, causing the exclusion of native grasses and inhibiting the development of small woody plants. The absence of edge effect on other components of the vegetation suggests, at first, that this is not a major threat to the conservation of the Cerrado. However, the biological invasion by the African grass is relatively recent (it was locally introduced about three decades ago) and its consequences have not been adequately assessed. It is possible that their impacts on the upper strata of the vegetation may be observed in future, when the inhibition of regeneration of shrub and tree species jeopardize the dynamics of plant community and the replacement of adults in the populations of these species. In addition, at present the invasion has significant impacts only over 0-20 m from the edge, but it is impossible to predict whether the invasive grass will expand or not into the core area of the fragment in the future.

No presente trabalho, estudamos uma área de vegetação natural, composta principalmente por cerrado, com 1269 ha, situada no munícipio de Santa Rita do Passa Quatro, estado de São Paulo (21 36-44 S e 47 34-41 W). O levantamento florístico da área foi efetuado em 18 excursões de coleta mensais, com duração de 3 ou 4 dias cada, entre setembro de 1995 e fevereiro de 1997. Em cada uma das formações e fisionomias de cerrado existentes (cerradão, cerrado sensu stricto, campo cerrado, campo úmido, mata ciliar, floresta estacional semidecídua), o material em fase florífera ou frutífera ou de formação de esporos foi coletado e, posteriormente, prensado e identificado em nível específico. Coletamos 1944 exsicatas, representando 499 espécies, 317 gêneros e 107 famílias. As famílias que se destacaram foram: Asteraceae, Fabaceae, Poaceae e Rubiaceae. A comparação das formações e fisionomias de cerrado através de índice de similaridade ressaltou a unidade florística do cerrado. Para auxiliar a identificação das espécies coletadas, construimos chaves baseadas em caracteres vegetativos para as formações de cerrado sensu lato, campo úmido, mata ciliar e floresta estacional semidecídua. Para estudar a estrutura da comunidade vegetal, lançamos aleatoriamente parcelas nas fisionomias de cerrado e na floresta estacional semidecídua, cujos tamanhos e critérios de inclusão foram diferentes em função de variações no componente lenhoso. A biomassa, estimada pelo volume cilíndrico total, aumentou do campo cerrado à floresta estacional semidecídua, com valores intermediários no cerrado sensu stricto e no cerradão. O cerrado, em suas três fisionomias, apresentou não só grande diversidade alfa, como também altas diversidades beta e gama. A partir dos dados do levantamento florístico, estudamos as variações fenológicas das espécies, procurando analisá-las como estratégias adaptativas. A proporção de espécies anemo e autocóricas foi maior no componente herbáceo-subarbustivo, ao contrário das zoocóricas, mais freqüentes no componente arbustivo-arbóreo. As espécies arbustivo-arbóreas floresceram principalmente no início da estação chuvosa, enquanto que as herbáceo-subarbustivas produziram flores, de modo geral, apenas no final da estação úmida, após período de acúmulo de carboidratos. A proporção de espécies anemo e autocóricas em frutificação foi maior na estação seca, quando sua dispersão é mais eficiente. Já as espécies zoocóricas frutificaram principalmente durante toda a estação quente e chuvosa, quando seus frutos carnosos podem se manter atraentes por mais tempo. / We studied a natural vegetation area, composed mainly by cerrado, with 1269 ha, located at Santa Rita do Passa Quatro municipality, São Paulo State, southeastern Brazil (21 36-44 S e 47 34-41 W). We carried out a floristic survey in 18 field trips, each one with 3 or 4 days, from September 1995 to February 1997. On each existing vegetation types (three cerrado physiognomies, floodplain grassland, gallery forest, and seasonal semidecidous forest), all vascular plants in reproductive stage were collected and then pressed and identified in species level. A total of 499 species, representing 317 genera and 107 families, was found. The most important families were: Asteraceae, Fabaceae, Poaceae and Rubiaceae. The comparison of all vegetation types and cerrado physiognomies through similarity index emphasized the cerrado floristic unity. To help the species identification, we constructed four indented keys based on vegetative characters, one for each vegetation type (cerrado, floodplain grassland, gallery forest, and seasonal semidecidous forest). To study the plant community structure, we placed randomly quadrats in the cerrado physiognomies and in the seasonal semidecidous forest, with different sizes and inclusion criteria according to its woody component. Biomass, estimated by total cylindric volume, increased from campo cerrado to seasonal semidecidous forest, with intermediate values in cerrado sensu stricto and cerradão. Cerrado, on its three physiognomies, showed high alpha diversity as well as beta and gamma ones. Based on the data collected during the floristic survey, we studied the phenological variations, analysing them as adaptive strategies. The ratio of anemo and autochorous species was greater in the herbaceous component. The zoochorous ones, on the other hand, were more frequent in the woody component. The woody species flowered mainly at the beginning of the rainy season, while the herbaceous ones produced flowers generally at the end of that season, after a period of carbohydrate accumulation. The anemo and autochorous species produced fruits principally at the dry season, when its dispersion is more efficient. The zoochorous ones fruited along the whole rainy and warm season, when its fruits become attractive for longer time.

A distribuição e a abundância das espécies de lepidópteros podem ser determinadas por vários fatores tais como disponibilidade de recursos, fatores genéticos, climáticos e inimigos naturais. Este estudo avaliou as relações entre espécies de Lepidoptera e de Malpighiaceae encontradas em dois fragmentos de cerrado do Estado de São Paulo. Para tanto, o trabalho procurou responder às questões: 1) Qual a similaridade da fauna de lagartas entre as espécies de Malpighiaceae?; 2) Quais as características vegetais que influenciam a diversidade de lepidópteros? 3) As mesmas relações se mantêm em fragmentos distintos? Os resultados encontrados demonstram que espécies de mesmo gênero de Malpighiaceae não apresentam necessariamente maior similaridade de fauna de lepidópteros, uma vez que houve maior similaridade entre Byrsonima intermedia, Byrsonima coccolobifolia e Banisteriopsis pubipetala. Não houve correlação direta entre algumas características vegetais como: a concentração de nitrogênio e taninos, a densidade de tricomas e a herbivoria. As defesas vegetais das Malpighiaceae parecem influenciar a diversidade destes herbívoros, uma vez que a riqueza e abundância estão relacionadas à essas características. A presença de alcalóides e a fauna associada a Banisteriopsis stellaris reforça essa sugestão. A similaridade da fauna de lagartas entre os dois fragmentos de 42,2% e algumas diferenças observadas nas concentrações de nitrogênio e taninos nas mesmas espécies vegetais nas duas áreas sugerem que fatores ambientais influenciam o fenótipo das plantas e as associações com seus herbívoros. Com base nos resultados encontrados, são sugeridos estudos complementares para melhor compreensão das complexas relações entre lepidópteros e as espécies de Malpighiaceae. / Species distribution and abundance are determined by several factors such as resource availability, genetics, weather and natural enemies. The present study focused on the relationships between Lepidoptera and Malpighiaceae species on two Cerrado fragments at São Paulo State. The following questions were addressed: 1) How similar is the caterpillar fauna among Malpighiaceae species?; 2) What are the plant characteristics influencing Lepidoptera diversity? 3) Are plant-Lepidoptera relationships kept on distinct fragments? Present data suggests that plants of different species of same genus have not, necessarily, the highest faunal similarity, e.g., the highest similarity among Byrsonima intermedia, Byrsonima coccolobifolia and Banisteriopsis pubipetala. No direct correlations were found among some plant characteristics such as nitrogen and tannin concentrations, trichome density and herbivory. However, Malpighiaceae defenses probably influenced herbivore diversity, because Lepidoptera species´ richness and abundance were related to these characteristics. Alkaloids and the specific fauna of Banisteriopsis stellaris support this suggestion. The caterpillar fauna similarity of 42,2% between fragments and some differences on nitrogen and tannin concentrations of same species from distinct fragments suggest that environmental factors affect, considerably, plant phenotype and plantherbivore interactions. Based on these results, some complementary studies were suggested to approach the complex relations between Lepidoptera and Malpighiaceae species.

Doctor of Philosophy / Department of Geography / Marcellus M. Caldas / Biofuel ethanol has been proposed as the most viable solution to mitigate greenhouse gas emissions (GHG) from the transportation sector; however, the impact of such production on the environment is not completely known. Environmental impacts are of more concern when ethanol production occurs in areas of high biodiversity value such as the Cerrado (Brazilian savanna). The Cerrado is a global biodiversity hotspot and an important breadbasket—at the same time, it is on a path to becoming the major sugarcane ethanol-producing region in Brazil. The main goal of this dissertation is to examine the impacts of sugarcane expansion on farmers’ land use decision processes in the Cerrado and to consider its consequences on biodiversity and the impacts of climate change. In the following chapters, land change dynamics are investigated using a combination of theory and methods from geography, GIScience, economics, and ecology. Chapter 2 presents an examination of the drivers for the sugarcane expansion. The findings suggest that the Cerrado attracted mills because of the good agricultural conditions, affordable land prices, and favorable state-level fiscal incentive policies, while factors that have prevented traditional sugarcane-producing regions from meeting the increasing demand for ethanol. Chapter 3 develops a procedure to identify intensification and extensification responses at the field level. The main finding is that extensification is the main response. Additionally, this response has a higher probability of occurrence the farther an area is from a mill. Chapter 4 applies the partial adjustment framework to understand farmers’ land use decisions regarding sugarcane production. Estimates found that price of cattle have the largest cross-price elasticity with sugarcane acreage. In addition, the results suggest that acreage of sugarcane and soybean double-crop are positively correlated. Chapter 5 focuses on the impacts of climate change on land suitability for sugarcane and amphibian species. The findings show that land suitability for sugarcane is vulnerable to climate change and that the Brazilian zoning policy for sugarcane is not addressing this issue. Additionally, amphibians are affected by climate change and conflict with areas suitable for sugarcane in climate change scenarios.

>Magister Scientiae - MSc / There have been increasing calls to monitor Groundwater-Dependent Ecosystems (GDEs) more effectively, since they are biodiversity hotspots that provide several ecosystem services. The accurate monitoring of GDEs is an indispensable under Sustainable Development Goal (SDG) 15, because it promotes the existence of phreatophytes. It is imperative to monitoring GDEs, since their ecological significance (e.g., as biodiversity hotspots) is not well understood in most environments they exist. For example, vegetation diversity in GDEs requires routine monitoring, to conserve their biodiversity status and to preserve the ecosystem services in these environments. Such monitoring requires robust measures and techniques, particularly in arid environments threatened by groundwater over–abstraction, landcover and climate change. Although in–situ methods are reliable, they are challenging to use in extensive transboundary groundwater resources such as the Khakea-Bray Transboundary Aquifer.

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