Orientador: Alessandra Tomaselli Fidelis / Resumo: Sistemas savânicos são compostos por espécies herbáceas, principalmente gramíneas C4, as quais se expandiram há milhões de anos atrás, alterando a ocorrência de fogo nas regiões sub e tropicas do globo terrestre. Assim sendo, em sistemas como o Cerrado, onde o fogo está presente há pelo menos 4 milhões de anos, as espécies selecionadas por este fator possuem atributos inflamáveis que contribuem para a propagação das chamas. A essa capacidade que diversas espécies possuem de entrarem em combustão e serem consumidas, chamamos de inflamabilidade, sendo um componente essencial dos sistemas inflamáveis, contribuindo para o regime de fogo do ambiente, a partir de fatores ambientais, como a sazonalidade, e composição de espécies. Sendo assim, este trabalho teve como objetivo compreender a inflamabilidade das espécies herbáceas de ambientes savânicos do Cerrado, bem como entender quais são os grupos e os atributos vegetais que mais influenciam a inflamabilidade do sistema de acordo com a sazonalidade do ambiente. Diferentes espécies de herbáceas, arbustos e gramíneas foram coletadas em áreas de campo sujo do Cerrado durante a estação chuvosa e ao longo da estação seca (começo, meio e fim). Medições dos atributos de inflamabilidade (temperatura máxima, taxa de queima e biomassa consumida) e morfofisiológicos (biomassa morta, teor de umidade e área específica foliar) dessas espécies foram realizadas durante tais épocas, afim de compreender se existia variações na inflamabilidade. Além ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Savanna ecosystems are essentially covered by herbaceous species, mostly C4 grasses, which have a huge expansion million years ago, altering the fire occurrence in the sub and tropical regions of the world. Therefore, fire-prone ecosystems as the Cerrado, have fire present about 4 million years ago, which selected species with flammable traits enhancing the flames propagation. That capacity that several species possess to be consumed and spread the fire is called flammability, which is an essential component of flammable systems, contributing to fire regime, together with environmental factors, as seasonality and species composition. Thus, this study had the main aim understand the flammability of herbaceous species of the Cerrado open savannas physiognomies, besides understand which are the species groups and traits that most influence the system flammability, according to seasonality. Different species of forbs, shrubs and graminoids were collected in areas of Cerrado campo-sujo during the wet season and over the dry season (early, mid and late-dry). Flammability (maximum temperatures, burning rate and burnt biomass) and morphophysiological traits (dead biomass, moisture content and specific leaf area) measurements were taken across seasons, to understand the flammability changes. Moreover, 21 grass species were also collected in the middle of the dry season in two different regions of Cerrado campo-sujo, where the same traits were measured, to evaluate the variability of f... (Complete abstract click electronic access below) / Mestre

Reference ecosystems are a valuable tool for restoration and management efforts in degraded ecosystems. Longleaf pine (Pinus palustris), a pyrophytic southeastern U.S. ecosystem, have declined precipitously in extent since European settlement. Pine mortality and growth patterns were examined in a 15-year re-measurement study in two old-growth stands. Both stands experienced postire mortality and short-lived decreases in basal area. Distance to nearest neighbor had a significant effect on mortality of small (<10 cm DBH) pine. To better approximate reference conditions, saplings of five co-occurring hardwood species were destructively measured for bark accumulation and taper using bark and wood thickness. Significant species differences were detected in bark:wood ratio (P<0.001), with no difference in wood diameter. Blackjack oak (Quercus marilandica) had a bark:wood ratio 3x the closest species and steeper slopes of bark accumulation, suggesting that it is a fireapted species. These results will inform reference conditions for critical regional pine restoration efforts.

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Chan, Wing Shing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 201-222). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (in Chinese) --- p.iv / Acknowledgements --- p.vi / Table of contents --- p.viii / List of tables --- p.xii / List of figures --- p.xiv / List of plates --- p.xvi / Chapter Chapter One --- Introduction / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Research background --- p.2 / Chapter 1.3 --- Conceptual framework --- p.6 / Chapter 1.4 --- Objectives of the study --- p.10 / Chapter 1.5 --- Significance of the study --- p.11 / Chapter 1.6 --- Organization of the thesis --- p.12 / Chapter Chapter Two --- Literature Review / Chapter 2.1 --- Land degradation: an overview --- p.14 / Chapter 2.2 --- Land degradation in Hong Kong --- p.17 / Chapter 2.3 --- Ecological rehabilitation --- p.20 / Chapter 2.4 --- Role of plantation in ecological rehabilitation --- p.22 / Chapter 2.5 --- Reforestation history in Hong Kong and species selection --- p.25 / Chapter 2.6 --- Nutrient requirements of native species --- p.31 / Chapter 2.7 --- The geology and soils of Hong Kong --- p.35 / Chapter 2.7.1 --- Geology --- p.35 / Chapter 2.7.2 --- Soils --- p.35 / Chapter 2.8 --- Greenhouse approach in nutrient requirement study --- p.37 / Chapter 2.9 --- Nitrogen mineralization --- p.38 / Chapter 2.10 --- Chlorophyll fluorescence --- p.40 / Chapter 2.11 --- Summary --- p.41 / Chapter Chapter Three --- Inherent Characteristics and Properties of Decomposed Granite and Fire-affected Soil / Chapter 3.1 --- Introduction --- p.42 / Chapter 3.2 --- Materials and methods --- p.42 / Chapter 3.2.1 --- Sources of soil and sampling --- p.43 / Chapter 3.2.2 --- Soil pre-treatment --- p.44 / Chapter 3.3 --- Laboratory analysis --- p.45 / Chapter 3.3.1 --- Reaction pH and conductivity --- p.45 / Chapter 3.3.2 --- Texture --- p.46 / Chapter 3.3.3 --- Organic carbon --- p.46 / Chapter 3.3.4 --- Total Kjeldahl nitrogen (TKN) --- p.47 / Chapter 3.3.5 --- Carbon: nitrogen ratio --- p.47 / Chapter 3.3.6 --- Total phosphorus (TP) --- p.47 / Chapter 3.3.7 --- Exchangeable Al and H --- p.48 / Chapter 3.3.8 --- "Exchangeable cations, base saturation percentage (BSP) and exchangeable Al percentage" --- p.48 / Chapter 3.4 --- Results and discussion --- p.49 / Chapter 3.4.1 --- Texture --- p.49 / Chapter 3.4.2 --- Reaction pH and conductivity --- p.49 / Chapter 3.4.3 --- "Soil organic matter, total Kjeldhal nitrogen and total phosphorus" --- p.51 / Chapter 3.4.4 --- Exchangeable cations --- p.52 / Chapter 3.4.5 --- DG as a representative soil of soil destruction sites --- p.54 / Chapter 3.4.6 --- FAS as a representative soil of vegetation disturbance sites --- p.56 / Chapter 3.5 --- Summary --- p.58 / Chapter Chapter Four --- Nitrogen Fluxes of Decomposed Granite and Fire-affected Soil Amended with Urea / Chapter 4.1 --- Introduction --- p.59 / Chapter 4.2 --- Materials and methods --- p.62 / Chapter 4.2.1 --- Experimental design --- p.62 / Chapter 4.2.2 --- Soil incubation and sampling --- p.63 / Chapter 4.2.3 --- Analysis of mineral nitrogen (NH4-N and NO3-N) --- p.64 / Chapter 4.2.4 --- Statistical analysis --- p.64 / Chapter 4.3 --- Results and discussion --- p.64 / Chapter 4.3.1 --- Variation of NH4-N in DG and FAS --- p.64 / Chapter 4.3.2 --- Variation of N03-N in DG and FAS --- p.68 / Chapter 4.3.3 --- Variation of mineral N in DG and FAS --- p.74 / Chapter 4.3.4 --- NH4-N fluxes in DG and FAS --- p.78 / Chapter 4.3.5 --- NO3-N fluxes in DG and FAS --- p.80 / Chapter 4.3.6 --- Mineral N fluxes in DG and FAS --- p.82 / Chapter 4.4 --- Summary --- p.86 / Chapter Chapter Five --- Growth Performance of Native Species in Decomposed Granite and Fire-affected Soil / Chapter 5.1 --- Introduction --- p.88 / Chapter 5.2 --- Materials and methods --- p.91 / Chapter 5.2.1 --- Experimental design --- p.91 / Chapter 5.2.2 --- Nitrogen treatments --- p.94 / Chapter 5.2.3 --- Post-planting care --- p.95 / Chapter 5.2.4 --- "Measurement of survival rate, height, basal diameter, aboveground biomass and foliar nitrogen" --- p.95 / Chapter 5.2.4.1 --- Survival rate --- p.96 / Chapter 5.2.4.2 --- Height and basal diameter --- p.96 / Chapter 5.2.4.3 --- Aboveground biomass --- p.96 / Chapter 5.2.4.4 --- Foliar sampling --- p.97 / Chapter 5.2.4.5 --- Determination of foliar nitrogen --- p.97 / Chapter 5.2.5 --- Statistical analysis --- p.97 / Chapter 5.3 --- Results and discussion --- p.98 / Chapter 5.3.1 --- Survival rate --- p.98 / Chapter 5.3.2 --- Height growth of species in DG --- p.105 / Chapter 5.3.3 --- Effect of nitrogen on species height growth in DG --- p.112 / Chapter 5.3.4 --- Height growth of species in FAS --- p.117 / Chapter 5.3.5 --- Effect of nitrogen on species height growth in FAS --- p.118 / Chapter 5.3.6 --- Effect of DG and FAS on species height growth --- p.120 / Chapter 5.3.7 --- Basal diameter growth of species in DG --- p.122 / Chapter 5.3.8 --- Effect of N on basal diameter growth of species in DG --- p.124 / Chapter 5.3.9 --- Basal diameter growth of species in FAS --- p.126 / Chapter 5.3.10 --- Effect of N on basal diameter growth of species in FAS --- p.127 / Chapter 5.3.11 --- Effect of DG and FAS on species basal diameter growth --- p.127 / Chapter 5.3.12 --- Overall height and basal diameter growth of species in DG . --- p.129 / Chapter 5.3.13 --- Overall height and basal diameter growth of species in FAS --- p.131 / Chapter 5.3.14 --- Aboveground biomass of species in DG --- p.133 / Chapter 5.3.15 --- Effect of N on aboveground biomass of species in DG --- p.135 / Chapter 5.3.16 --- Aboveground biomass production in FAS --- p.138 / Chapter 5.3.17 --- Effect of N on aboveground biomass of species in FAS --- p.139 / Chapter 5.3.18 --- Effect of DG and FAS on aboveground biomass of species --- p.141 / Chapter 5.3.19 --- Foliar nitrogen --- p.143 / Chapter 5.3.19.1 --- Foliar N of species grown in DG --- p.143 / Chapter 5.3.19.2 --- Effect of N amendment on foliar N of species in DG --- p.147 / Chapter 5.3.19.3 --- Foliar N of species in FAS --- p.149 / Chapter 5.3.19.4 --- Effect of N amendment on foliar N of species in FAS --- p.151 / Chapter 5.3.19.5 --- Effect of DG and FAS on the foliar N of species --- p.152 / Chapter 5.4 --- Summary --- p.155 / Chapter Chapter Six --- Photosynthetic Efficiency of Native Species / Chapter 6.1 --- Introduction --- p.158 / Chapter 6.2 --- Materials and methods --- p.160 / Chapter 6.2.1 --- Measurement of chlorophyll fluorescence --- p.160 / Chapter 6.2.2 --- Statistical analysis --- p.162 / Chapter 6.3 --- Results and discussion --- p.162 / Chapter 6.3.1 --- Photosynthetic efficiency of species in DG --- p.162 / Chapter 6.3.2 --- Photosynthetic efficiency of species in FAS --- p.170 / Chapter 6.3.3 --- Effect of DG and FAS on photosynthetic efficiency of Species --- p.172 / Chapter 6.4 --- Summary --- p.175 / Chapter Chapter Seven --- Conclusions / Chapter 7.1 --- Introduction --- p.178 / Chapter 7.2 --- Summary of major findings --- p.179 / Chapter 7.3 --- Implications of the study --- p.187 / Chapter 7.3.1 --- Species selection for the rehabilitation of soil destruction sites --- p.187 / Chapter 7.3.2 --- Species selection for the rehabilitation of vegetation disturbance sites --- p.191 / Chapter 7.3.3 --- Fertilization practice in different degraded lands --- p.193 / Chapter 7.3.4 --- The importance of soil test in ecological rehabilitation Planting --- p.195 / Chapter 7.4 --- Limitations of the study --- p.197 / Chapter 7.5 --- Suggestions for further study --- p.198 / References --- p.201 / Appendices --- p.223

From the 1920's through 1951 several severe fires occurred in the predominantly conifer forest ecosystems of the northern Oregon Coast Range. Of the 211,151 ha. of mapped area, 57 percent was burned. The effects of frequent fires with high severity on forest ecosystems over time at the landscape level is not fully understood. A reconstruction of fire history was conducted to help investigate the effects of fire severity, frequency, and area extent on distribution of postfire tree regeneration, species composition, and stand tree size, as well as on current species composition and stand tree size. I hypothesized that: 1) vegetation patterns (1950's and 1988) would vary with time, because the persistence of disturbance effects (fire, logging, reforestation) on forest vegetative responses varied, and 2) environmental controls (topography, soil, climate) would become the primary influences when disturbance events were absent. In this study historical maps, sketches and notes were used to reconstruct spatial and temporal patterns of fires from the 1920's to 1951 and to identify unburned patches on a Geographic Information System. Relationships between fire regime and postfire and current vegetative patterns were tested. Constructing precise spatial data layers from early maps, produced before the availability of aerial photography or satellite image, was difficult. Historical map accuracy and quality were variable and poor by present day standards. Geographic reference points were used to transform inappropriate map scales. The reconstruction of spatial data was used to characterize spatial patterns of historic fires: my estimates of burn areas were similar to estimates in the literature. To reduce questionable data along fire and vegetation patch boundaries for hypothesis testing, an exclusion approach was used. Data within a 100 m width of fire and vegetation type boundary lines were called a fuzzy zone and removed from raw data. The distribution of various attributes in the reduced data was similar to the distribution of the complete data set. Regression analysis examined the effects of fire, logging, reforestation, topography, climate, and soil type on vegetation patterns. Patterns of postfire (1950's) species composition, tree regeneration and tree size (DBH) were associated with the effects of fires, as well as influences of logging and soil type. Indices of fire occurrences (reflecting the time variation and severity of fires) frequently correlated to the 1950's vegetation patterns. The number of fires (frequency) did not cause great differences in vegetation patterns. Current (1988) species composition and tree size (after absence of fire for more than three decades) were correlated more with terrain variables. Plant succession also influenced the current vegetation patterns. Neither the date or number of fires caused marked differences in distribution of species and tree size, except large conifers were found in areas missed by fires. Postfire and current vegetation patterns were correlated with soil types which reflect the influence of topographic and climatic characteristics. However, historic fires occurred frequently on some soil types. Fires have a confounding influence on soil type. This confounding influence of fire on soil type cannot be avoided. Reforestation efforts appeared to have little influence on the postfire and current vegetation patterns. I inferred that the short time period of reforestation effects did not show its importance on the 1950's vegetation landscape. Although regression analysis results did not support my hypothesis, by 1988, reforested area in the northern Coast Range had increased since 1950's. Most of the large fire-open patches became mixed forest in about 3 decades may still relate to the force of reforestation. On private unburned ownerships conifer forests in 1955 were subsequently cut and replaced by mostly mixed forest by 1988. The analysis supported the hypotheses that soil type, aspect and plant succession were dominant influences on current (1988) vegetation patterns, while forest disturbances such as fire and logging were important influences on the immediate postfire (1950's) patterns. The results not only interpret the relationship between historic disturbances and vegetation distribution, but may also serve as a useful background for the management of the future forest landscape. / Graduation date: 1998 / Presentation date: 1997-07-11

Self-organized spatial patterning of microtopographic features is a trademark characteristic of the Everglades landscape. Anthropogenic modifications to Everglades’ hydrology have reduced and degraded pattern, where ridges occur at higher elevations and spread into open water sloughs under dryer conditions. Wildfire is an important ecological force in the central Everglades and may maintain ridge-slough patterning through reducing ridge size and complexity, and thus preserve habitat heterogeneity. To investigate fire as a patterning mechanism in the central Everglades I examined the shape complexity and area distribution of ridges along a chronosequence of time since fire. Shape complexity did not change following fire, but small and large ridges became more prominent and eventually spread as time since fire increased, suggesting fire may maintain ridge area distribution. Documentation of fires’ effect on ridge size will inform ecosystem and conceptual models detailing the complex interactions that maintain the Everglades ridge-slough patterning. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

O Cerrado é considerado uma das savanas mundiais, onde as ocorrências de queimadas são comuns. Portanto, o fogo é um importante agente seletivo do meio, ou filtro ambiental, e tem grande influência na dinâmica ecológica e evolutiva de todos os organismos que lá habitam. Das espécies da fauna e flora endêmicas das savanas, muitas apresentam algum tipo de adaptação que favorece sua sobrevivência durante e após as queimadas. As queimadas naturais ocorrem sob diferentes regimes de fogo, que compreendem: frequência - intervalo de tempo entre queimadas; intensidade - caracterizada pelo calor liberado na combustão; época - estação do ano; e tipo - conforme o estrato vegetacional predominantemente queimado, a direção do vento e a topografia local. Embora haja, na literatura, muitos estudos sobre os efeitos ecológicos do fogo nas savanas, estudos genéticos tendo como o fogo um importante agente seletivo são recentes. No Brasil, o único local em que se desenvolve um projeto de longo prazo para estudar a dinâmica dos regims de fogo é na Reserva Ecológica do IBGE, Brasília-DF. O local contém cinco parcelas permanentes, em que foram estabelecidos quatro diferentes frequências de fogo: três delas com queimas bianuais, uma com queimas quadrienais e uma livre do fogo. Escolhemos a espécie Vellozia squamata Pohl como modelo para averiguar possível influência de diferentes regimes de fogo no nível genético. O estudo foi pautado na seguinte pergunta: A variabilidade e a estruturação genética para indivíduos de uma mesma população variam sob diferentes regimes de fogo? Hipóteses (1) A variabilidade genética não se altera com o regime de fogo e, (2) A estruturação genética não se altera com o regime de fogo. Para tanto, foram desenvolvidos 51 marcadores do tipo microssatélite para a espécie, dos quais 10 foram utilizados para genotipagem da população amostral de V. squamata. Os resultados indicam que a diversidade é alta em todos os tratamentos (H&#772e=0,79 e SH&#772e= 0,004) e há alta endogamia intrapopulacional (F&#772IS=0,413), o que sugere a ocorrência de autofecundação e/ou cruzamentos entre os indivíduos aparentados. A variabilidade estimada entre os tratamentos foi considerada intermediária (F&#7721ST = 0,084), indicando a existência de variação entre tratamentos e relacionado com a deriva genética , assim como se verificou haver variabilidade devida a diferentes frequências de fogo entre os tratamentos, por meio de AMOVA (análise de variância molecular). A correlação espacial das frequências alélicas no espaço mostrou-se restrita, indicando um fluxo até 174 m, e esta estimativa corrobora o valor intermediário de (F&#772ST = 0,084) (variabilidade populacional). Os parâmetros genéticos populacionais estimados são importantes para inferir sobre a diversidade e estrutura genética da espécie e gerar subsídios para sua conservação, assim como responder como a diversidade e estrutura genética podem ser afetadas por diferentes frequências de fogo / The Cerrado is considered one of the world\'s savannas, where fire occurrences are common. Therefore, fire is an important selective agent in the middle, or environmental filter, and its great influence on the ecological and evolutionary dynamics of all organisms that inhabit savannas. Species of flora and fauna endemic to the savanna, many have some kind of adaptation that favors their survival during and after the fires. In savannas, the firings occur under different natural fire regimes, comprising: frequency - time interval between fires; intensity - reflected by the heat released in the combustion; season - season, and type - as predominantly burned vegetation stratum, direction wind and local topography. While there, in the literature, many ecological studies on the fire in the savannas, genetic studies as having an important selective agent fire is recent. In Brazil, the only place that develops a long-term project to study the dynamics of Fire Regimes is the Ecological Reserve of IBGE, Brasília-DF. The site contains five permanent plots were established in four different frequencies of fire: three firings biannual, one with burns and a missing four-year closeouts. We chose the kind Vellozia squamata Pohl as a model to investigate whether there was variation in the genetic diversity of different frequencies due to fire, as well as the genetic structure of the population. The study was guided by the following question: Variability and genetic structure for individuals within a population vary under different frequencies of light? Assumptions (1) genetic variability does not change with the frequency of fire, and (2) genetic structure does not change with the frequency of fire. For the realization of the project, were developed for the species of type 51 microsatellite markers, of which 10 were used for genotyping of the sample population of V. squamata. The results indicate that the diversity is high in all treatments (H&#772e=0,79 e SH&#772e= 0,004) and a high inbreeding within populations (F&#772IS=0,413), suggesting the occurrence of selfing and/or intersections among related individuals. The estimated variability among treatment populations had intermediate (F&#7721ST = 0,084), indicating the existence of variation between treatments and related genetic drift (subdivision of treatments) and was found to have variability due to different frequencies of fire between treatment by means of AMOVA (molecular analysis of variance). The spatial correlation of allele frequencies in space proved to be restricted, indicating a flow up to 174 m this estimate confirms the intermediate value of (F&#772ST = 0,084) (population variability). These genetic parameters estimated are important to infer the genetic diversity and structure of the species and generate subsidies for conservation, as well as responding to diversity and genetic structure can be affected by different fire frequencies

The successful completion of this work is dedicated first to my grandparents for having always shown their unwavering love and encouragement in my journeys (most of which they kindly and politely only pretended to understand) and for having also served as life-long role models who upheld an unparalleled work ethic. To many whom I consider to be my chosen family, especially Ann Williams and Brittany Sears, who kept me laughing, but more importantly, kept my crazy train from derailing during these tumultuous years. To Wayne Price and Tom Jackman, who fostered the success of my career and are the epitome of patience and kindness. To DeAngelis, for the many hours of laughter, conversations, and adventuresome treks that further kindled my knowledge, love, and respect for Florida’s ecology. To family in Alabama who have either helped shape my brazen character or made this education possible. To Taego, the one to whom I am bound through so many of the stories that begin with, “Remember when…?” and who is often so kind and thoughtful though he still holds tightly to the stereotype of the selfish youngest sibling. Finally, to Fen for being my smiling, bright blue-eyed, spunky kid who has been on this journey with me from the get-go; for keeping me from getting too big for my britches; for your intrinsic fire that burns for equality, fairness, and friendship; and for inspiring me to be the best example of a mother that I can possibly be.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 98-108). Also available on the World Wide Web.

Thesis (M.S.)-Oregon State University, 1975. / Typescript (photocopy). Includes bibliographical references (leaves 120-127). Also available via the Internet.