Student Number : 9008538J - MSc Dissertation - School of Biology - Faculty of Science / O’Regan SP, 2005. The long-term effects of fire frequency and season on the woody vegetation in the Pretoriuskop sourveld of the Kruger National Park. MSc Dissertation, University of the Witwatersrand, Johannesburg. The role of fire in the management of conservation areas has historically been a contentious issue in which traditional agricultural principles and ever-changing conservation principles tend to collide. The Kruger National Park (KNP) in the early 1950s was no exception where the appropriate use of fire and its ecosystem consequences were hotly debated. The controversy surrounding the management of fire in the KNP highlighted the significant lack of understanding of fire and its role in the ecosystem and because of this controversy, the Experimental Burn Plot (EBP) experiment was established in 1954. The EBP experiment comprised 12 treatments, and a pseudo-randomised block design was used in which the 12 fire treatments were replicated four times each in four of the six major vegetation zones identified at the time. The EBP experiment originally comprised 192 experimental plots approximately 7 Ha in size each and covered approximately 12 km2 in the KNP. The twelve fire treatments were an annual burn in August, biennial and triennial burns in February, April, August, October, and December, and a control on which fire was excluded. Despite having been plagued with negative assessments from internal and external researchers from its inception, the EBP experiment was meticulously maintained, and it has now become a valuable research asset in the KNP. Four replicates of twelve plots each were located in the Pretoriuskop sourveld landscape of the KNP. These replicates were named Fayi, Kambeni, Numbi, and Shabeni after nearby landmarks. The Pretoriuskop region is a moist infertile mesic-savanna, which experiences on average 744mm of rain annually. The dominant tree species in Pretoriuskop are Dichrostachys cinerea and Terminalia sericea and the dominant grass species is Hyperthelia dissoluta. A baseline survey of the woody vegetation was done on all the Pretoriuskop plots in 1954 by HP Van Der Schijff. A second survey of the woody vegetation on all the Pretoriuskop plots was done in 1996 by SP O’Regan. This provided a 42-year period of treatment application over which the effects of fire frequency and season on the woody vegetation of the Pretoriuskop region were studied. The aim of this study was to investigate the long-term effects of the twelve fire treatments on the density, structure, and species composition of the woody vegetation in Pretoriuskop. The objectives of this study were: 1. To carry out a complete re-survey of the trees and shrubs on the Pretoriuskop EBPs using similar methods as those used in the baseline survey in 1954. 2. To capture into a digital format pertinent woody vegetation survey data from surveys that had been conducted on the Pretoriuskop EBPs between 1954 and 1996. 3. To compare the density, structure, and composition of the woody vegetation on the Pretoriuskop EBPs between 1954 and 1996, to determine the effects of fire on the woody vegetation of Pretoriuskop. 4. To investigate the history of the Kruger National Park Experimental Burn Plots experiment. The four replicates in the Pretoriuskop region were found generally to have very similar woody vegetation traits (density, species composition, and structural composition). However, the EBPs were established and surveyed in two distinct phases, the first phase comprised the control, August Annual, and the Biennial plots, and the second phase comprised the Triennial plots. The baseline structural composition of the plots established in the first phase was different from the structural composition of the plots in the second phase. Furthermore, the Pretoriuskop EBPs are located in two distinct vegetation types, namely the open and the closed Terminalia sericea \ Combretum woodlands of the Pretoriuskop region. The Numbi and Shabeni replicates are in the open Terminalia sericea \ Combretum woodlands, and the Kambeni and Fayi replicates are in the closed Terminalia sericea \ Combretum woodlands. It was found that the species composition of the plots was influenced by the location of the plots in the different vegetation types. The exclusion of fire in the Pretoriuskop sourveld results in an increase in the density of the overstorey and understorey woody vegetation, and an increase in the number of species, species diversity, and species evenness. This is because fire sensitive and fire intolerant woody species become more abundant as the period between fires increases. In Pretoriuskop, there is no evidence of relay floristic succession, because fire sensitive and fire intolerant woody species do not replace fire tolerant species. Instead, the floristic succession is accumulative and fire tolerant, fire sensitive, and fire intolerant woody species coexist as the period between fires increases. Woody species tolerant of frequent fires in Pretoriuskop are Albizia versicolor, Catunaregam spinosa, Lonchocarpus capassa, Pavetta schumanniana, Senna petersiana, Strychnos madagascariensis, and Turraea nilotica. Woody species that are sensitive or intolerant of fire in Pretoriuskop are Acacia swazica, Bauhinia galpinii, Combretum mossambicense, Commiphora neglecta, Croton gratissimus, Dalbergia melanoxylon, Diospyros lycioides, Diospyros whyteana, Euclea natalensis, Hyperacanthus amoenus, Kraussia floribunda, Ochna natalitia, Olea europaea, Psydrax locuples, Putterlickia pyracantha, Tarenna supra-axillaris, and Zanthoxylum capense. Dichrostachys cinerea and Terminalia sericea were found to dominate in areas that had been burnt frequently as well as areas where fire has been excluded. The change in the density of the woody vegetation as the inter-fire period increases is not linear but rather J shaped with an initial decrease in the density as the inter-fire period increases from 1 year to 3 years. This initial decrease in density is the result of a loss of very short (<1m tall) woody individuals. In contrast, there is no initial decrease in the number of tree equivalents (phytomass) of the woody vegetation as the inter-fire period increases. After the initial decrease in the density of the woody vegetation, the density increases as the inter-fire period increases beyond 3 years. Generally in Pretoriuskop, post fire age of the vegetation was found to be an important factor affecting the structure of the woody vegetation, and as the inter-fire period increases the number of structural groups, the structural diversity, and the structural evenness of the woody vegetation increases. As the inter-fire period increases the number of single-stem individuals relative to the number of multi-stem individuals increases, and the average height of the woody vegetation increases. The findings regarding the effects of fire frequency on the Pretoriuskop EBPs were similar to the findings on other fire experiments in mesic African savannas. The finding on the Pretoriuskop EBPs differed from the findings in other fire trials that were in arid savannas in Africa. Generally, the exclusion of fire in moist savannas (> 600 mm of rain annually) results in the woody vegetation becoming denser, while the exclusion of fire in arid to semi-arid savannas (< 600mm of rain annually) does not result in the woody vegetation becoming denser. In Pretoriuskop, fires occurring in summer between December and February have a different impact on the density, species composition, and structure of the woody vegetation than fires occurring in winter between August and October. Furthermore, fires occurring in April have a different impact on the density, species composition, and structure of the woody vegetation in Pretoriuskop. Woody vegetation burnt by summer fires is denser than woody vegetation burnt by winter fires. The number of species and species diversity of the woody vegetation is also higher in vegetation burnt by summer fires in comparison with vegetation burnt by winter fires. The density and species composition of woody vegetation in areas that have been burnt in summer fires is more similar to areas where fire has been excluded than to areas that have been burnt in winter fires. The woody species associated with vegetation burnt in summer fires and where fire has been excluded are Euclea natalensis, Antidesma venosum, Diospyros lycioides, Phyllanthus reticulatus, Grewia flavescens, Grewia monticola, Ochna natalitia, Peltophorum africanum, Rhus pyroides, Diospyros mespiliformis, Rhus transvaalensis, Securinega virosa, Putterlickia pyracantha, Rhus pentheri, Commiphora neglecta, Heteropyxis natalensis, and Olea europaea. Structurally the average height of the woody vegetation is taller in areas burnt by winter fires than in areas burnt by summer fires. The woody vegetation in areas burnt in summer fires have more single-stem individuals relative to multi-stem individuals than in areas burnt in winter fires. The structural composition of areas burnt in summer fires is more similar to areas where fire has been excluded than with areas burnt in winter fires. The structure of the woody vegetation in areas burnt in winter fires is generally dominated by multi-stem individuals that are 0-1m tall or 3-5m tall. The structure of the woody vegetation in areas burnt in summer fires or where fire has been excluded is dominated by both single-stem and multi-stem individuals of all heights and basal diameters. Findings regarding the effect of early dry season fires (April) in comparison with late dry season fire (August) on the woody vegetation are consistent with the findings on other fire trails in Africa. However, a comparison of all the fire-timing treatments between the Pretoriuskop and Satara EBPs in the KNP reveals that the timing of fires affects the woody vegetation differently in different areas even when the affects at certain times appear similar. The data collected on the Pretoriuskop EBPs reveals that there have been significant changes in the woody vegetation in Pretoriuskop between 1954 and 1996. The density of the woody vegetation increased between 1954 and 1996 by almost 200%. The number of species and the species diversity of the woody vegetation also increased between 1954 and 1996. In 1954, there were approximately equal numbers of single-stem and multi-stem individuals, while in 1996 there were more multi-stem individuals than single-stem individuals. The increase in atmospheric CO2 levels between 1954 and 1996 is believed to have been a factor that has driven the changes in the woody vegetation of Pretoriuskop between 1954 and 1996.

La compréhension des facteurs qui déterminent la nature et la dynamique du couvert végétal en Afrique centrale représente un enjeu important face aux changements climatiques et à la pression sociale en cours. Forêt et savane sont souvent considérées comme deux états alternatifs stables et très contrastés, déterminés par de complexes interactions entre le couple sol-climat et les perturbations. Les liens actuels entre structure du couvert arboré et déterminants (déficit hydrique annuel, fréquence des feux, densité de population, intensité d'utilisation des terres et type de sol) ont été caractérisés à l'aide d'images satellites et d'un modèle statistique. Il a ainsi été montré qu'il non pas un mais existe plusieurs états stables de savane. Pour les états de faible couvert arboré (≤ 35%), ce sont principalement le type de sol et le climat qui déterminent leur présence et le passage de l'un à l'autre de ces états. Les savanes plus arborées (> 35%) ainsi que les forêts semblent être les états les plus sensibles aux perturbations anthropiques. Cependant, ce modèle statistique ne décrit que les liens contemporains entre structure de la végétation et déterminants. En revanche, l'étude des bio-indicateurs environnementaux conservés dans des archives naturelles, et qui représente l'approche paléo-écologique, permet de reconstruire sur le temps long la végétation, les perturbations et certaines données climatiques, et ainsi obtenir une vision dynamique de leurs relations. Trois lacs, situés actuellement en forêt, en mosaïque de forêt et de savane, et en savane ont été étudiés. En comparant sédiments récents et images satellites, ainsi qu'en calibrant un modèle entre bio-indicateurs dans les sols et relevés de végétation, il a été possible de mieux comprendre ce qu'enregistrent les bio-indicateurs disponibles pour notre étude (phytolithes et charbons principalement) et donc d'estimer la structure de la végétation et l'activité de feux. Les résultats de ces études soulignent l'importance de bien cerner les processus taphonomiques pour reconstruire précisément les paléo-environnements. Les résultats préliminaires d'une paléo-séquence lacustre couvrant les 3000 dernières années sont présentés en discussion. Bien que l'environnement autour du lac soit resté une savane, cette dernière a subi des changements de structure important dus à la fois aux changements climatiques et aux modifications des régimes de feu. De plus, ces changements de structure ne semblent pas graduels, mais s'effectuent de façon abrupte, comme ils le sont actuellement le long du gradient climatique. Ces travaux prédisent donc une réponse critique des biomes tropicaux aux changements globaux en cours. / Understanding the factors that determine vegetation nature and dynamics in Central Africa is an important issue given climatic changes and increasing human pressure. Forest and savanna are often considered as two alternative stable and highly contrasted states, driven by complex interactions between climate, soil and disturbances. The current relationships between tree cover and its determinants (annual water deficit, fire frequency, population density, intensity of land use and soil type) were characterized using remote sensing data and a statistical model. It has been shown that there is not one, but several savanna stable states. For savanna states of low tree cover (≤ 35%), it is mainly the soil type and the annual water deficit which determine their presence and the transition from one to another. The most wooded savannas (> 35%) and the forests seem to be the most sensitive to anthropogenic disturbances. However, this statistical model can only describe the contemporary relationships between vegetation structure and its determinants. Conversely, studying environmental bio-proxies preserved in natural archives, which constitutes the paleo-ecological approach, enables reconstructing long-term vegetation, disturbances and some climatic features, in order to obtain a dynamic view of their relationships. Paleo-sequences from three lakes, currently located in a forest, in a savanna-forest mosaic, and in a savanna, were investigated. On the one hand bio-proxies from recent lake sediments were compared to satellite images, and on the another hand a statistical model between bio-proxies from modern soils and vegetation surveys was calibrated. The results of these studies enabled to better understand the information carried by phytoliths and charcoals, and therefore to better estimate vegetation structure and fire history. Moreover, they emphasize the importance of precisely identifying taphonomic processes in order to accurately reconstruct paleo-environments. The preliminary results of a lacustrine paleo-sequence covering the last 3000 years are presented in discussion. Although the environment around the lake has remained a savanna, vegetation structure has undergone significant changes due to both climate change and modifications in fire regimes. Moreover, it seems that these structural changes were not gradual but happened abruptly, as it happens currently along the climatic gradient. This work therefore predicts a critical response of tropical biomes to global changes.

Understanding the ecology of invasive species is vital to curb the homogenizing of ecosystems, yet the pollination mechanisms of the Chinese tallow tree (Triadica sebifera) in its introduced habitat remain ambiguous. This study examines self-pollination, wind pollination, and flower-visiting insects of tallow in a bottomland hardwood forest and Longleaf pine savannah in the U.S. Gulf South. These data suggest that self-pollination and airborne pollination are possible, but likely rare occurrences, although the possibility of apoxisis was not investigated. Seed production in exclusion experiments was significantly less than in open-pollinated flowers, and wind dispersal of tallow pollen dropped to essentially zero 8 meters from the source. Results show that tallow is primarily bee pollinated, with external pollen loads of Apis, Melissodes, and halictids visiting at similar rates, and Xylocopa species visiting less frequently. The researchers believe that to date, this is the first study of the pollination mechanisms of T. sebifera in its introduced range and recommend further study to understand the ecology of this destructive invasive species.

Student Number : 9904953T - PhD thesis - School of Animal, Plant and Environmental Science - Faculty of Science / This study seeks to combine the knowledge of science and society to elicit the relationship between the harvesting of woody plant species and the local availability of woody species in South African savannas. Ten villages located in the former communal areas and homelands within three broad vegetation types (i.e., Mixed lowveld bushveld, Eastern thorn bushveld, and Natal lowveld bushveld) were studied. The study, conducted in the framework of the coupled human-environment system poses challenges to both scientists and managers (e.g., setting common goals). Data were collected using modified Whittaker plots (MWP) and focus group discussions (FGD), denoting ecology and society, respectively. There were nine 1000m² MWP plots sampled per village, each having nested 1m², 10m² and 100m² subplots. The FGD involved six groups of local people based on gender and age. The study revealed that the harvesting of woody plant species is a source of local disturbance to woody vegetation. Generally, there were more woody species in locations farther from settlements, having a mean of 41.97 ± 3.9, than for the intermediate (38.27 ± 5.6) and near locations (19.9 ± 4.2) within the 1000m² plots, the result of the reduction in species closer to settlements from higher harvesting levels. The larger sampling plot size of 1000m² of the MWP had the highest diversity, decreasing sequentially to the smallest scale (1m²). The density of the woody species was highest in the intermediate locations (517 ± 80 plants/ha), followed by the far and near, relative to the settlements. The Natal lowveld bushveld broad vegetation type had the highest mean density of trees (573 ± 71 trees/ha) compared to the Mixed lowveld bushveld (366 ± 64 trees/ha) and the Eastern thorn bushveld (312 ± 40 trees/ha). The stem diameters of trees were generally higher in the villages of the Mixed lowveld bushveld than the other two vegetation types. The study reaffirmed that anthropogenic disturbances within savannas impact vegetation and need to be studied concurrently with other disturbance factors (e.g., biotic and abiotic or environmental). The mean total coppice shoots of stumps within the 1000m² plots was relatively higher in the near locations (38.4%), than the far (33.0%) and intermediate (28.7%). This difference in coppicing shows that although near locations were less species rich, which is a result of disturbance, the growth of shoots may nevertheless be greater. Harvesting disturbance will possibly favour the regeneration of some species, as well as the maintenance of biodiversity. Whilst 135 woody species (from a total 191 from 42 plant families) sampled in the field were used by the local people, the community knowledge yielded almost twice as many (267 species, from 69 plant families). The ratio of mean useful woody species to total woody species remained relatively constant at about 1.0:1.1 from the near to far locations around the villages and accompanied by increased woody species diversity with distance from village. The MWP sampling yielded eight broad use categories (i.e., medicinal, wild edible fruits, fuelwood, housing and fencing poles, craft (e.g., carving), cultural, local beverages (e.g., alcohol)), and nine for the FGD (the eight for the MWP plus indigenous furniture). According to the local people, the highest number of species was used for medicine (27.8% of species), followed by fuelwood (19.2%) and wild edible fruits/seeds (19.1%). Over half of the species had multiple uses (i.e., three to eight uses), raising questions of possible threats to their persistence. Useful woody species were not restricted to any particular location or vegetation type. Large sized trees were subjected to even more uses than smaller trees, another source of conservation concern. Fifteen of the woody plant species are presently protected by law in South Africa (e.g., Adansonia digitata, Podocarpus latifolius, Mimusops caffra, Philenoptera violacea), while others are facing various forms of regional threats (e.g., Alberta magna, Catha edulis, Ocotea bullata). There is the need to popularise and make people (both local and outsiders) aware of the state of NTFP species, using local and village level information as an additional criterion for describing conservation threat (e.g., proposed “Locally Brown List” – Chapter 4). The older generation of local people were highly knowledgeable in terms of the woody species used for medicine, craft, fencing and housing poles, the middle aged in beverage making species, and the younger generation in fuelwood species. Overall, older males were highly knowledgeable of the useful species. The generally strong correlation (r = 0.99, p <0.0001) between the cumulative woody species diversity from field and community knowledge suggests the need to integrate data using multi-disciplinary approach and also to manage NTFP species. Although threat reduction assessments (TRA) and monitoring have previously been suggested, the participation of local people, harvesters and users will be crucial in making TRAs effective. In conclusion, the harvesting of NTFPs, and the impacts of the changes in the NTFP species on total diversity in savannas need to be understood in order to move towards a more holistic approach to conserving the woody species that may be at risk of extinction through harvesting. Disturbance criteria that describe harvesting levels should be set to guide research and management protocols. Finally, when discussing NTFPs and the species from which they are harvested, management should aim at incorporating all the factors that affect sustainability, such as land and resource tenure and local participation, the political economy, appropriate production and development cycles.

Com o objetivo de compreender quais fatores abióticos determinam a ocorrência das diferentes formações florestais na região de Batatais, entre as coordenadas 20038S e 20058S e 47037W e 47028W, foram escolhidas três propriedades agrícolas (Fazenda Monte Belo, em Restinga, SP e Fazenda Magnólia e Sítio Pratinha, em Batatais, SP), que apresentavam remanescentes florestais representativos da região (floresta ribeirinha paludícula, floresta estacional semidecídua ribeirinha e cerradão). Para descrever a composição florística e a estrutura da comunidade arbórea foram amostradas 05 parcelas de 10 x 10 m ao redor de cada estação tensiométrica. Para o estudo dos fatores abióticos foram determinados os parâmetros físicos e químicos dos solos e as curvas de retenção de água nos solos e piezometria. A discriminação das variáveis abióticas e de vegetação foi feita através da análise de componentes principais (PCA) e, na correlação entre a abundância de espécies e fatores abióticos, foram feitas análises diretas de gradiente por meio de Análise de Correlação Canônica (CCA). A textura dos solos (teores de argila, silte e areia) e a posição no terreno (cota), foram as variáveis ambientais mais importantes na distribuição das espécies e nas variações das fisionomias florestais, com influência na retenção hídrica e nos índices de fertilidade dos solos. Essas diferenças nos teores de argila em profundidade ao longo do declive, com influência direta na retenção de umidade dos solos ou mesmo na formação de ambientes paludículos, determinaram grupos distintos de espécies e fisionomias florestais: (i) um grupo de espécies de ocorrência típica nas fisionomias de Cerrado e fortemente associado às cotas mais elevadas (solos menos férteis, bem drenados e porcentagens mais baixas de argila e silte nas camadas mais profundas), entre as quais: Matayba juglandifolia, Trichilia pallida, Lithraea molleoides, Anadenanthera falcata, Myrcia tomentosa, Copaifera langsdorffii, Erytrhoxylum pelleteranum, Platipodium elegans, Chrysophyllum marginatum, Luehea divaricata, entre outras e (ii) um grupo com espécies indicadoras de Florestas Paludículas ou de ocorrência comum nestas fisionomias, associado aos solos das cotas mais baixas (Gleissolos), com porcentagens altas de argila e silte nas camadas superficiais, mais férteis e maior retenção hídrica: Cecropia pachystachya, Citronella gongonha, Rapanea guianensis, Talauma ovata e Tapirira guianensis. Pode-se considerar um terceiro grupo de transição entre Floresta Estacional Semidecídua e Cerradão, nas cotas intermediárias e menos úmidas (espécies amostradas em parcelas localizadas nas bordas das Florestas Paludículas), onde ocorreram espécies tanto de ambiente de Cerradão, como de Floresta Estacional Semidecídua, e algumas poucas de ambiente paludículo. As porcentagens mais elevadas de Areia nos solos do Sítio Pratinha, com influência na menor retenção hídrica e também nos índices de fertilidade (solos álicos, com maior acidez e os menos férteis), podem explicar algumas diferenças na composição e abundância das espécies entre fisionomias florestais iguais. O Cerradão da Fazenda Monte Belo, mostrou-se diferente floristicamente do Cerradão do Sítio Pratinha. Esta mesma diferença ocorreu em relação às Florestas Paludículas da Fazenda Magnólia e a do Sítio Pratinha. As poucasespécies de ocorrência comum tiveram populações diferentes. A CCA evidenciou também correlações de algumas espécies com determinadas variáveis de solo. / In order to understand what abiotic factors determine the occurrence of different forest formations in the region of Batatais, coordinated between 20038\'S and 20058\'S and 47037\'W and 47028\'W, three agricultural properties were chosen (Monte Belo, in the city of Restinga, SP and Magnolia and Pratinha in Batatais, SP, Brazil), which had forests representative of the region (swamp forest, semi-deciduous riverine forest and forested savanna). To describe the floristic composition and structure of the arboreal community, 05 plots of 10 x 10 meters around each tensiometric station were sampled. For the study of abiotic factors, the physico-chemical characteristics of the soils, the soil-water-retention curves and the groundwater fluctuation were determined. The discrimination of the environmental variables and arboreal species were made through the Principal Components Analysis (PCA), and in the correlation between the abundance of species and abiotic factors, direct analyses of gradient through Canonical Correspondence Analysis (CCA) were made. The texture of the soil (levels of clay, silt and sand) and the position on the ground (altitude) were the most important environmental variables in the distribution of species and variations of forest physiognomies, with influence in the retention rates of water and soil fertility. These differences in levels of clay in depth along the slope, with direct influence on the retention of soil moisture and even in the development of swampy environment, determined distinct groups of species and forest physiognomies: (i) a group of species of typical occurrence in physiognomies of Forested Savanna and strongly associated with higher altitude (less fertile, well-drained soil and lower percentages of clay and silt in the deeper layers), including: Matayba juglandifolia, Trichilia pallida, Lithraea molleoides, Anadenanthera falcata, Myrcia tomentosa, Copaifera langsdorffii, Erytrhoxylum pelleteranum, Platipodium elegans, Chrysophyllum marginatum, Luehea divaricata, among others, and (ii) a group with indicator species of Swamp Forests or common occurrence in these physiognomies, associated with lower altitude (Gleisoil), with high percentages of clay and silt in the upper and more fertile layers, and greater water retention: Cecropia pachystachya, Citronella gongonha, Rapanea guianensis, Talauma ovata and Tapirira guianensis. A third group of transition between Semi-deciduous Forest and Forested Savanna, in intermediate altitude and soils less humid (species sampled in plots located at the edges of Swamp Forests), occurred both in the Forested Savanna and in Semi-deciduous Forest and a few in swampy environment. The highest percentages of sand in the soil of Pratinha, with less influence on water retention and also on the rates of fertility (alic soils, with greater acidity and less fertile), may explain some differences in the composition and abundance of species of forest physiognomies equal. The forested Savanna of Monte Belo, has proved floristically different from the Forested Savanna of Pratinha. This same difference occurred in swamp forests of Magnolia and Pratinha. The few species of common occurrence had differentpopulations. The CCA also revealed correlations of some species with certain variables of soil.

Made available in DSpace on 2016-08-10T10:44:51Z (GMT). No. of bitstreams: 1 BRUNO DE ANDRADE MARTINS.pdf: 6958513 bytes, checksum: fe1bde1f26390c8c17a53602f7423d35 (MD5) Previous issue date: 2006-06-23 / Many native species of the cerrado (Brazilian savanna) constitute important sources with potential of economic exploration. There is little information regarding the characteristics of the biodiversity in the cerrado, as well as adequate technologies of processing for nourishing products. In such a way, this work had objectives to evaluate the physico-chemical properties of the fruits of the cerrado, in natura and processed, with intention to generate information of the possibility for use in the multimixtures, beyond awakening the scientific community on the potential of the native fruits for the elaboration of new products and nutritional complements. For this, it was necessary, to determine the nutritional composition of the fruits in natura (araticum, baru, cagaita, cajuí, jatobá, lobeira and mangaba); to process them through viable and applicable technologies, as the toasting or freeze-drying, in accordance with its intrinsic characteristics, and to verify alterations in its nutritional compositions after the dehydration, through physico-chemical analyses, in triplicate, as the norms of the Institute Adolph Lutz. The fruits, araticum, cagaita, lobeira and mangaba had presented satisfactory properties for the consumption in natura, therefore they are rich in nutrients. The freeze-drying process, although slow and of limited application, presented the advantage to keep, practically unchanged, some attributes of quality, increasing the shelf-life and the availability of the seasonal fruits, beyond reducing the weight and the volume. Araticum and the lobeira had revealed adequate, after the freeze-drying process, due to texture and income, keeping some sensorial characteristics. The solid fruits (baru, cajuí and jatobá) had presented excellent properties for the consumption, rich in nutrients, as proteins, lipids and minerals, beyond the safe food characteristics, in the microbiological point of view. The process of toasting, used to dehydrate baru and jatobá, revealed fast and without risk of danger to the health of the manipulator. The use of the biodiversity of the cerrado can be an economic alternative for the supported development of the region. / Muitas espécies nativas do cerrado brasileiro constituem importantes fontes, em potencial, de exploração econômica. Verificam-se poucas informações a respeito das características da biodiversidade do cerrado, assim como de tecnologias adequadas de processamento para produtos alimentícios. Desta forma, este trabalho teve como objetivos avaliar as propriedades físico-químicas de frutas do cerrado, in natura e processadas, com o intuito de gerar informações da possibilidade do uso em multimisturas, além de despertar a comunidade científica sobre o potencial dos frutos nativos para a elaboração de novos produtos e complementos nutricionais. Para isso, foi necessário, determinar a composição nutricional dos frutos in natura (araticum, baru, cagaita, cajuí, jatobá, lobeira e mangaba); processá-los por meio de tecnologias viáveis e aplicáveis, como a torrefação ou liofilização, de acordo com suas características intrínsecas, e verificar alterações em suas composições nutricionais após a desidratação, por meio de análises físico-químicas, em triplicatas, conforme as normas do Instituto Adolfo Lutz. As frutas, araticum, cagaita, lobeira e mangaba apresentaram propriedades satisfatórias para o consumo in natura, pois são ricas em nutrientes. O processo de liofilização, apesar de lento e de aplicação limitada, apresentou a vantagem de manter, praticamente inalterados, alguns atributos de qualidade, aumentando a vida-de-prateleira e a disponibilidade das frutas sazonais, além de reduzir o peso e o volume. O araticum e a lobeira mostraram-se adequados, após liofilização, devido à textura e rendimento, mantendo algumas características sensoriais. Os frutos sólidos (baru, cajuí e jatobá) apresentaram excelentes propriedades para o consumo, ricas em nutrientes, como proteínas, lipídios e minerais, além das características de alimentos seguros, no ponto de vista microbiológico. O processo de torrefação, utilizado para desidratar o baru e o jatobá, mostrou-se rápido e sem risco à saúde do manipulador. A utilização da biodiversidade do Cerrado pode ser uma alternativa econômica para o desenvolvimento sustentado da região.

As samambaias do gênero Pteridium caracterizam-se pelas largas frondes e por um sistema de rizomas subterrâneos que possibilita sua rápida expansão. Apresentam elevada produção de biomassa ao longo do ano, que aumenta a incidência de incêndios, e ainda liberam substâncias químicas consideradas alelopáticas. Atualmente, são conhecidas como plantas-problema, pois vêm se expandindo e ocupando grandes áreas em diversas partes do mundo, causando impacto econômico e ecológico. Nesse contexto, este estudo teve por objetivo geral a compreensão do impacto da invasão por Pteridium arachnoideum sobre a vegetação de cerrado e a elucidação dos mecanismos por meio dos quais vem sendo lentamente revertido o processo de invasão na área de estudo. Para tanto, analisamos áreas de cerradão invadidas há mais de quatro décadas na Estação Ecológica de Assis (EEcA), no sudoeste do estado de São Paulo. Analisamos a composição florística e estrutura da comunidade em uma área invadida dentro da EEcA. Avaliamos os componentes do estrato arbóreo e regenerante da comunidade, a fim de verificar quais as espécies que conseguiram ultrapassar as barreiras físicas e químicas impostas pela presença da samambaia. Para tanto, comparamos a vegetação da área invadida com uma área adjacente não invadida, com ambiente e histórico de perturbações semelhantes. Utilizamos 100 pontos quadrantes para amostragem da composição florística e, para caracterização da estrutura da comunidade, alocamos 15 parcelas de 10 m x 30 m para amostrar o estrato superior, dentro das quais foram instaladas sub-parcelas de 2 m x 30 m para o estrato intermediário e de 2 m x 2 m para o estrato inferior. Medimos a cobertura das copas das árvores dentro das parcelas e estimamos a porcentagem de cobertura do solo por Pteridium. As espécies que conseguiram ocupar a área no início da invasão são tolerantes à sombra e com ritmo de crescimento rápido, características que possibilitaram que tais espécies ultrapassassem a barreira de samambaia e se estabelecessem na área. Já as espécies do estrato inferior se assemelham às da área não invadida, indicando que está havendo uma substituição das espécies na comunidade vegetal. A baixa densidade das árvores na área invadida diminui a competição entre os indivíduos, que, por sua vez, investem em aumento de tamanho, sendo consideravelmente maiores do que as árvores do cerradão não invadido. Essas árvores, que formam o estrato arbóreo atualmente, estão facilitando a regeneração natural de espécies arbóreas nativas e, assim, revertendo, lentamente, o processo de invasão. Testamos quais variáveis, relacionadas às funções ecológicas e aspectos estruturais das árvores de grande porte que se estabeleceram nas áreas invadidas, estão favorecendo as plantas em regeneração sob suas copas. Para tanto, amostramos os indivíduos maiores que 50 cm sob a copa de árvores sistematicamente selecionadas, segundo atributos funcionais e estruturais. Verificamos que as árvores que possuem copas mais densas e perenifólias apresentaram mais regenerantes sob suas copas. A resiliência característica do cerrado tem possibilitado que as áreas invadidas consigam se recuperar, podendo se assemelhar futuramente às áreas de cerradão da EEcA, porém muito lentamente. Ações de manejo que almejam a restauração dessas áreas mais rapidamente devem focar seus esforços na eliminação do Pteridium e/ou na introdução de espécies que possuam as características das árvores que atuam como facilitadoras da regeneração. / The genus Pteridium comprises bracken species recognized by large fronds and a rhizome system that allows their fast expansion. Bracken presents an elevated biomass production throughout the year, that increases fire occurrence and release chemical compounds that are considered allelopathic. Nowadays, species of the genus Pteridium are well known as problem-species, due to their expansion and occupation of large areas around the world, causing great economic and ecological impacts. Aiming at the comprehension of bracken invasion over cerrado vegetation, we studied its impact over the plant community and, also, the slow natural regeneration process of cerrado recovery after invasion. We analyzed savanna woodland areas that have been invaded for over four decades, at Assis Ecological Station (EEcA), in southwestern São Paulo State. We analyzed the floristic composition and the plant community structure in an invaded area, compared to a non invaded patch of savanna vegetation. Components of the arboreal and regeneration strata were analyzed, in order to verify which species managed to pass by the physical and chemical barrier imposed by bracken. We assessed 100 points to assemble the floristic composition, using the quarter method, and for the community structure we used 15 plots of 10 m x 30 m to assemble the superior strata. The intermediate layer was assessed by sub-plots of 2 m x 30 m and the inferior strata using 2 m x 2 m sub-plots. We measured the canopy cover and also bracken cover inside the plots. The arboreal species first occupying the invaded area are shadow tolerant and fast growing, attributes which allowed them to overtake the bracken layer and establish. Nowadays, the invasive species has been replaced by a high number of arboreal species, the inferior strata being floristically similar to the area not invaded. The low density of adult trees in the invaded area reduce the competition among individuals that end up investing in growth, with greater size compared to those trees in the non invaded area. These large trees function as nurse trees, facilitating other species to establish under their canopies. We tested which variables related to the ecological functions and tree structure are favouring the understory, in order to comprehend the ecological processes and interactions that regulate the assembly rules of the invaded community being recovered. We assembled all individuals from arboreal species over 50 cm high growing under the projection of nurse trees canopy. These nurse trees were systematically selected, for the basis of functional and structural attributes. Understory density and richness were higher under trees with dense and permanent shadow, and that was the attribute better explaining the recovery process. The high resilience of savanna have helped the recovery of invaded areas. This process, however, has been very slow. Interventions whiling to restore those areas should be focused on bracken eradication and/or introduction of those species that can facilitate the natural regeneration.

Apesar de vários estudos já terem examinado os efeitos de queimadas naturais, respostas das aves, como variação do padrão da comunidade, guilda trófica e das espécies, ao manejo de fogo ainda não foram investigadas em reservas do Cerrado, Este trabalho teve como objetivo comparar a avifauna em trechos de campo sujo manejados (aceiros) e não manejados por fogo no Parque Nacional das Emas, Brasil Central. Este é o primeiro trabalho a avaliar os efeitos do manejo do fogo prescrito sobre comunidades de aves no Cerrado. Foram selecionados 12 locais de estudo. Em cada local, havia um transecto no aceiro e outro em campo sujo não manejado. Uma amostra consistiu em percorrer um transecto de 800m a pé, anotando as aves detectadas visual ou auditivamente a 15m do observador. Frequência de ocorrência e abundância das espécies e das guildas tróficas, riqueza total, abundância total da comunidade de aves e composição de espécies encontradas nos dois ambientes foram comparadas. No total, foram 881 registros e 41 espécies de aves. A riqueza e a abundância total de aves foram significativamente menores em aceiros. Houve diferença na composição de espécies de aves entre campos não manejados por fogo e aceiros. Dentre as guildas tróficas, os onívoros foram mais frequentes em campos não manejados. Granívoros, nectarívoros e onívoros foram mais abundantes em vegetação não manejada. Das 21 espécies analisadas separadamente, a coruja Athene cunicularia foi a única indicadora de aceiros e também mais frequente e abundante em aceiros. Por outro lado, foram identificadas quatro espécies indicadoras de campos sujos não manejados (Melanopareia torquata, Xolmis cinerea, Neothraupis fasciata e Coryphaspiza melanotis). Tais espécies podem ser usadas como indicadores ecológicos do regime e histórico do fogo e podem fornecer informações se os objetivos das ações de manejo do fogo estão sendo atingidos. Sete espécies foram mais frequentes e oito espécies foram mais abundantes em campos não manejados. Três dessas espécies são endêmicas do Cerrado (M. torquata, N. fasciata e Cypsnagra hirundinacea) e quatro estão sob algum grau de ameaça e são altamente sensíveis a distúrbios (Polystictus pectoralis, Alectrurus tricolor, C. melanotis e C. hirundinacea). Assim, cuidado e atenção devem ser redobrados para essas espécies, pois possuem alto valor para conservação e menor frequência ou abundância em aceiros. A menor riqueza e abundância de aves encontrada em aceiros devem estar relacionadas ao menor uso desse habitat, indicando menor disponibilidade de recursos como alimento, reprodução e abrigo, dado que o fogo altera a estrutura e composição da vegetação. Isso demonstra uma diminuição da qualidade do ambiental geral dos aceiros, provocada pela sua atual forma de manejo. Propomos que a queima dos aceiros seja feita em intervalos de 3 anos, em vez de 1 2 anos como tem sido realizada. Dessa forma, seria mantida a função dos aceiros como controle e barreira efetiva de incêndios e também para conservação da biodiversidade. / Several studies have investigated the effects of natural fires on Cerrado birds. However, avian responses to fire management have not been examined. We compared birds found in firebreaks (fire managed areas) and in fire unmanaged grasslands, in Parque Nacional das Emas, Central Brazil. This is the first study to evaluate the effects of prescribed fire on the Cerrado avifauna. We selected 12 study sites. We established one transect in the firebreak and another one in an unmanaged grassland area in each study site. Each bird count sample consisted of walking through an 800m transect recording birds seen or heard 15m from the observer. Species richness, total bird abundance, species composition, feeding guilds abundance and frequencies of occurrence and species abundance found in firebreaks and unmanaged grasslands were compared. In total, 881 individuals and 41 species were recorded. Species richness and total abundance were significantly lower in firebreaks. Species composition was different between firebreaks and unmanaged grasslands. Omnivores were more frequent and more abundant in unmanaged grasslands. Granivores and nectarivores were more abundant in unmanaged grasslands. Twenty-one bird species were analyzed separately, one of which (Athene cunicularia) was indicator of firebreaks and also more frequent and abundant in firebreaks. On the other hand, we identified four indicator species of unmanaged grasslands (Melanopareia torquata, Xolmis cinerea, Neothraupis fasciata and Coryphaspiza melanotis). These species might be used as ecological indicators of fire regime and history, and also give information if fire management goals are being achieved. Seven species were more frequent and eight species were more abundant in unmanaged grasslands. Three of them are endemic of Cerrado (M. torquata, N. fasciata and Cypsnagra hirundinacea) and four of them are highly sensitive to human disturbances and threatened with extinction in some degree (Polystictus pectoralis, Alectrurus tricolor, C. melanotis e C. hirundinacea). Caution must be redoubled to these species, as they are of high conservation priority and less frequent and abundant in firebreaks. The lesser avifauna complexity in firebreaks than in unmanaged areas might be connected to the low use of this habitat, thus indicating lower resource availability, such as food, sites for reproduction and refuge. This is because fire changes vegetation structure and composition. We propose that firebreaks should be burnt every 3 years, instead of 1-2 years. In this way, fire management would keep its function as effective fire barriers and would also keep biodiversity conservation.

Submitted by Liliane Ferreira (ljuvencia30@gmail.com) on 2018-03-05T12:10:25Z No. of bitstreams: 2 Tese - Joyce Rodrigues Lobo - 2018.pdf: 2149724 bytes, checksum: 9ffc2cc35e80c43e0c544353ae4c1118 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-03-06T10:40:33Z (GMT) No. of bitstreams: 2 Tese - Joyce Rodrigues Lobo - 2018.pdf: 2149724 bytes, checksum: 9ffc2cc35e80c43e0c544353ae4c1118 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-03-06T10:40:33Z (GMT). No. of bitstreams: 2 Tese - Joyce Rodrigues Lobo - 2018.pdf: 2149724 bytes, checksum: 9ffc2cc35e80c43e0c544353ae4c1118 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-01-26 / Multivariate statistical analysis was used for environmental groupings in Cerrado and Caatinga evaluating the relationship between positive serological prevalences for brucellosis, bovine viral diarrhea (BVD), infectious bovine rhinotracheitis (IBR), leptospirosis, enzootic bovine leukosis (EBL), neosporosis and toxoplasmosis in bovine Curraleiro Pé-Duro, associated with socioeconomic data of the municipalities. Serological results were obtained from the Pro-Centro-Oeste Network database; socioeconomic variables of IBGE and environmental data of the Laboratory of Image Processing and Geoprocessing of UFG and National Institute of Meteorology, in two periods 2006 and 2011. Environmental variables were grouped, later was performed discriminant analysis and canonical correlation. In 2006, cluster 1 was located in the Cerrado-Amazonian transition area and were associated the prevalences of brucellosis, leptospirosis, EBL, IBR and BVD; Cluster 2 was characterized by vegetation typical of Cerrado and was related the prevalence of neosporosis and toxoplasmosis; Cluster 3 was differentiated by water stress and presented the intermediate values of prevalence; Cluster 4 was characterized by areas for environmental protection of the native vegetation; and cluster 5 constituted an anthropogenic environment in the Cerrado. In 2011, cluster 1 was characterized by Cerrado regions rich in natural vegetation and Caatinga, warmer, lower rainfall and low altitudes were associated with the prevalences of LEB, IBR and BVD; Cluster 2 in dry regions associated with the prevalence of neosporosis; Cluster 3 Cerrado antropizado with more hot and humid climate, higher rainfall at high altitudes related to the prevalence of leptospirosis and brucellosis, in dairy cattle. Evaluation of the landscape in the prevalence of bovine diseases reflects historical and socioeconomic aspects of agriculture. / Análise estatística multivariada foi utilizada para agrupamentos ambientais, em Cerrado e Caatinga avaliando a relação entre prevalências sorológicas positivas para brucelose, diarreia viral bovina (BVD), rinotraqueíte infecciosa bovina (IBR), leptospirose, leucose enzoótica bovina (LEB), neosporose e toxoplasmose de bovinos Curraleiro Pé-Duro, juntamente com dados socioeconômicos dos municípios. Resultados sorológicos foram obtidos do banco de dados da Rede Pró Centro-Oeste; socioeconômicos do IBGE e ambientais da plataforma de dados do Laboratório de Processamento de Imagens e Geoprocessamento da UFG e Instituto Nacional de Meteorologia, em dois períodos 2006 e 2011. Variáveis ambientais foram agrupadas, posteriormente foram realizadas análise discriminante e correlação canônica. Em 2006, cluster 1 localizou-se em área de transição Cerrado-Amazônia e associou-se as prevalências de brucelose, leptospirose, LEB, IBR e BVD; Cluster 2 caracterizou por vegetação típicas de Cerrado e relacionou-se as prevalências de neosporose e toxoplasmose; Cluster 3 diferenciou-se pelo estresse hídrico e apresentou os valores intermediários de prevalências; Cluster 4 caracterizou por áreas para proteção ambiental da vegetação remanescente; e cluster 5 constituiu-se ambiente antropizado no Cerrado. Em 2011, cluster 1 caracterizou-se por regiões de Cerrado ricas em vegetação natural e Caatinga, mais quentes, menor pluviometria e baixas altitudes associaram-se as prevalências de LEB, IBR e BVD; Cluster 2 regiões mais secas associadas a prevalência de neosporose; Cluster 3 Cerrado antropizado com clima mais quente e úmido, maior pluviosidade em elevadas altitudes relacionados as prevalências de leptospirose e brucelose, na pecuária leiteira. Avaliação da paisagem na prevalência de doenças bovinas reflete aspectos histórico e socioeconômico da agropecuária.

Orientador: Gustavo Habermann / Banca: José Pires de Lemos Filho / Banca: Rafael Vasconcelos Ribeiro / Resumo: As folhas são órgãos adaptados para a captação de energia luminosa e sua transformação em energia bioquímica. Entretanto, a irradiância interceptada pelas folhas é maior do que a irradiância que é de fato absorvida e aproveitada de forma eficiente, o que torna os mecanismos de fotoproteção essenciais. Esses mecanismos podem minimizar a absorção da irradiância ou ativar respostas metabólicas responsáveis pela proteção do sistema fotoquímico. Styrax camporum é uma espécie com ampla distribuição no cerrado sensu lato. Suas folhas possuem orientação horizontal ou vertical, mas também podem apresentar ângulos intermediários. Com a finalidade de observar a influência que a orientação foliar exerce sobre o desempenho fotossintético, foram avaliadas as curvas das taxas fotossintéticas em resposta ao aumento da disponibilidade de luz para ambas as faces (adaxial e abaxial) de folhas horizontais e verticais. Além disso, foi realizado um experimento de deficiência hídrica no qual as trocas gasosas, a fluorescência da clorofila a e as relações hídricas foram acompanhadas em ambas as faces dos dois tipos foliares. Os resultados mostraram que, em S. camporum, a orientação vertical de parte das folhas não está relacionada à fotoproteção estrutural e que, nessa espécie, o posicionamento vertical das folhas poderia estar relacionado à otimização da assimilação de CO2 em decorrência da potencial exposição de ambas as faces foliares à radiação direta / Abstract: Leaves are organs adapted to sunlight interception and conversion of light energy into biochemical energy. However, the irradiance that is intercepted by leaves is greater than the absorbed irradiance that is effectively used in photosynthesis, making photoprotective mechanisms essential. Such mechanisms may reduce the amount of absorbed irradiance or may activate metabolic activities that are responsible for protecting the photochemical system. Styrax camporum is a woody species that is widely distributed in the cerrado sensu lato areas. S. camporum leaves show horizontal or vertical orientation, but they may also have intermediate angles. We investigated whether the leaf angles of S. camporum have any influence on photosynthetic performance. Photosynthetic response curves in response to increasing light were measured on both surfaces (adaxial and abaxial) of horizontal and vertical leaves. In addition, a water deficiency experiment was performed. In this experiment, gas exchange rates, chlorophyll a fluorescence and plant water relations values were also monitored on both surfaces of both leaf types. Results showed that, in S. camporum, vertical leaf orientation is not related to structural photoprotection and that, in this species, such leaf orientation could be related to the optimization of CO2 assimilation since both leaf surfaces are potentially exposed to direct sunlight / Mestre