Neste estudo amostras coletadas de pinturas rupestres foram analisadas para identificação do material utilizado; análises da sua interação e de processos eventuais de degradação, além de atribuições quanto à sua origem, foram também feitas através da espectroscopia Raman. Pigmentos encontrados em pinturas rupestres em Minas Gerais foram identificados, junto a produtos de degradação microbiológica. A partir dos resultados, foi feita uma caracterização da transformação de desidratação do pigmento amarelo de goetita (α-FeOOH) a hematita (α-Fe2O3) por espectroscopia Raman na tentativa de contextualizá-la no problema da origem da hematita encontrada nas representações. Foram identificados os pigmentos calcita (CaCO3) para o branco, carvão vegetal para o preto, goetita (α-FeOOH) para o amarelo e hematita (α-Fe2O3) para o vermelho, que constituem basicamente a paleta de cores desse período. Produtos de degradação microbiológica foram identificados por espectroscopia Raman e no infravermelho por ATR como sendo whewellita (CaC2O4.H2O) e weddelita(CaC2O4.2H2O). A transformação topotática de goetita a hematita por aquecimento foi acompanhada por espectroscopia Raman in situ e ex-situ e infravermelho, na tentativa de caracterizar o processo quanto às fases formadas, possíveis marcadores, de maneira a complementar resultados da literatura que utilizaram outras técnicas, como difração de raio-X (XRD) e microscopia eletrônica de transmissão (TEM). Esse estudo foi realizado na tentativa de determinar a existência de possível manipulação térmica desses materiais como sugerido em trabalhos anteriores. Em particular, nos espectros Raman, o comportamento diferenciado da banda em torno de 660 cm-1 e a maior largura das bandas de uma maneira geral, presentes na chamada hematita desordenada, perfil que as amostras naturais coletadas apresentam, são marcadores do efeito de temperatura, uma vez que parecem estar ligados mais estreitamente ao deslocamento catiônico dos íons Fe do que ao rearranjo da gaiola octaédrica de oxigênios ao redor destes, durante a transição a partir de goetita. Esse comportamento dos espectros Raman é confirmado pelos padrões dos difratogramas de raio-X. Concluiu-se que esse desordenamento, entretanto, não é causado somente pela temperatura e, dessa forma, não pode ser usado para atestar inequivocamente como sendo resultado de processamento dos materiais (goetita). / This dissertation reports the investigation carried out on samples collected from rupestrian paintings, aiming at the identification of materials used, their interaction and degradation. The technique of choice was Raman microscopy as it is a non-destructive tool, which provides the spatial resolution necessary for the study of heterogeneous samples. Pigments were identified together with products of microbiological degradation. Thermal convertion of goethite (yellow) to hematite (red) was followed by Raman spectroscopy in a tentative to address the issue of the provenance of red pigments (natural hematite or heated goethite) found in the paintings. White pigments were identified as calcite (CaCO3), whereas charcoal was used as black, goethite (α-FeOOH) as yellow and hematite (α-Fe2O3) as red. These pigments are usually found in rock art palletes. Degradation products from microbiological activity were identified by Raman microscopy and ATR infrared spectroscopy as being whewellite (CaC2O4.H2O) and weddelite (CaC2O4.2H2O). The topotatic transition from goethite to hematite was followed by in situ and ex-situ Raman and infrared spectroscopy, regarding the characterization of the phases formed, possible markers, aiming to complement the previous results reported in the literature using other techniques such as X-ray diffractometry (XRD) and transmission eletron microscopy (TEM). The main goal of the study of temperature effect on the Raman spectrum of goethite was to determine whether hematite was used as found in nature or was obtained by goethite heating as suggested in previous investigations. Particularly, the behavior of the 660 cm-1 band and a larger linewidth for bands in the spectrum, present in the disordered hematite and in the red pigments analysed, are markers of the thermal processing. These features seem to be related to the movement of iron ions and to the rearrangment of the octahedrical cage formed by oxygen atoms around them. Such conclusions are in agreement with X-ray data. Unfortunately, temperature is not the only factor to cause such structural disorder and, hence, it cannot be used as an unequivocal marker of thermal processing.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-02-29T18:29:50Z No. of bitstreams: 1 josehugocamposribeiro.pdf: 1303041 bytes, checksum: 2d0e73ab107d3fd527acf0a40c9d095e (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-03-03T14:33:47Z (GMT) No. of bitstreams: 1 josehugocamposribeiro.pdf: 1303041 bytes, checksum: 2d0e73ab107d3fd527acf0a40c9d095e (MD5) / Made available in DSpace on 2016-03-03T14:33:47Z (GMT). No. of bitstreams: 1 josehugocamposribeiro.pdf: 1303041 bytes, checksum: 2d0e73ab107d3fd527acf0a40c9d095e (MD5) Previous issue date: 2013-03-07 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / (A vegetação lenhosa sobre solos quartzíticos na Serra Negra (Rio Preto, MG): estrutura, diversidade e gradientes ambientais.). A Serra Negra é um componente do complexo da Serra da Mantiqueira em Minas Gerais, Brasil. Apresenta um mosaico vegetacional onde predominam florestas ombrófilas e campos rupestres. Fisionomias arbustivo-arbóreas ocorrem sobre solos quartzíticos. O presente estudo tem o objetivo de investigar os padrões de estrutura e diversidade da vegetação lenhosa sobre solo quartzítico na Serra Negra e sua relação com as variáveis ambientais e édaficas. Dez parcelas (20m X 50m) foram alocadas aleatoriamente em manchas de campo rupestre ao longo da paisagem, totalizando um hectare de amostra. Foram medidos todos os indivíduos lenhosos com diâmetro a 30cm do solo (DAB) maior ou igual a 3 cm. Foram mensurados o DAB, altura e espécie de cada indivíduo. Para a análise das variáveis edáficas, foram coletadas amostras de solo superficial (20 cm de profundidade) em cada parcela. Foram levantadas ainda a altitude, declividade e porcentagens de cobertura por rocha, solo exposto e vegetação. Foram amostrados 1899 indivíduos, distribuídos em 30 famílias e 68 espécies. Foi encontrada uma forte dominância ecológica, com cerca de 30% dos indivíduos pertencentes a uma única espécie, Eremanthus incanus (Less.) Less. (Asteraceae). O índice de diversidade de Shannon (H’) encontrado foi de 2,74 nats/indivíduo e a equabilidade (J) foi de 0.65. A análise de correspondência canônica (CCA) mostrou que as variáveis altitude e cobertura por solo exposto foram as mais correlacionadas com a estrutura da vegetação. As duas espécies mais abundantes e ecologicamente importantes nesta fitofisionomia, E. incanus e E. erythropappus (DC.) MacLeish, apresentam potencial econômico e são exploradas na região, principalmente para lenha. A sobre exploração dessas espécies, aliada a outros fatores como o crescimento do turismo, podem apresentar riscos para a conservação da flora da região. / (The woody vegetation on quartzitic soils in Serra Negra (Rio Preto, MG): structure, diversity and environmental gradients.) Serra Negra is a part of the Mantiqueira range in Minas Gerais, Brazil. It presents a vegetation mosaic with the predominance of ombrophilous forests and rupestrian fields. Physiognomies with shrubs and trees occur on quartzitic soils. This study aims to investigate structure and diversity patterns of the woody vegetation on quartzitic soils in Serra Negra and the relationship with environmental and edaphic variables. Ten quadrats (20m X50m) were randomly located on rupestrian fields along the landscape, totaling one hectare. All individuals with diameter at 30cm above ground (DAB) equal or greater than 3cm were sampled. The diameter, height and species were measured for each individual sampled. To analyze the edaphic factors, samples of superficial soil (20 cm depth) were taken for each quadrat. Other variables analyzed were altitude, steepness and percentages of rock, exposed soils and vegetation coverages. 1899 individuals were sampled, which included 30 families and 68 species. We found a high dominance, with around 30% of the individuals belonging to a single species, Eremanthus incanus (Less.) Less. (Asteraceae). The Shannon index found was 2.74 nats/ind and the equability (J) was 0.65. The canonical correspondence analysis (CCA) showed that altitude and coverage by exposed soil were the variables with high correlation with vegetation structure. The most abundant and important species in this physiognomy, E. incanus e E. erythropappus, have economical value and are local explored for firewood. The overexploitation of this species allied with other factors, such the increases in tourist activities, could be a treat for the conservation of regional flora.

Orientador: Rafael Silva Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-20T21:06:58Z (GMT). No. of bitstreams: 1 Candido_HugoGalvao_M.pdf: 2416852 bytes, checksum: e2c495e1dc8a3aa3997d789f5761655e (MD5) Previous issue date: 2012 / Resumo: A disponibilidade de nutrientes tem um papel fundamental na estruturação de comunidades vegetais. Um modelo teórico recentemente proposto por Lambers et al. 2008 postula que em regiões com solos muito antigos e pobres em fósforo e nitrogênio, as espécies dominantes teriam maior proporção de especializações radiculares e menos associações com fungos micorrízicos. Estas regiões foram classificadas como OCBILs (do inglês: old, climatically buffered, infertile landscapes). Este estudo teve como objetivo testar tal modelo e avaliar se comunidades de campos rupestres podem ser categorizadas como OCBILs, avaliar se os campos rupestres podem ser considerados OCBILs mediante uma análise comparativa de um conjunto de caracteres morfofisiológicos das plantas e características físico-químicas do solo, através do estudo de seis comunidades na Cadeia do Espinhaço, Minas Gerais. Selecionamos as dez espécies mais abundantes em cada uma áreas distribuídas ao longo de um transecto de 190 km, totalizando 60 espécies. Avaliamos os atributos foliares (concentração de N, P, análise da massa foliar por unidade de área e razão N:P) e a colonização de raízes por micorrizas. Quimicamente, os solos dos campos rupestres têm baixa disponibilidade de P e N, comparáveis aos solos de outros OCBILs (oeste da Austrália e região do Cabo na África do Sul). A proporção de colonização das raízes das plantas por fungos foi positivamente correlacionada com a [P] do solo de cada comunidade, corroborando o modelo de Lambers em uma escala regional. Espécies de campos rupestres apresentam uma alta razão N:P foliar (média de 43 para todos os campos de estudo), maior que as encontradas nos outros OCBILs, o que sugere uma forte limitação por fósforo. Foram encontradas médias de 183 g m-2 para LMA, 12,46 mg g-1 para o N foliar e de 0,36 mg g-1 para o P foliar. Pelos resultados obtidos propomos que os campos rupestres devem ser classificados também como OCBILs, status que demandaria maior atenção para esses campos ainda pouco estudados e já ameaçados ecologicamente / Abstract: The availability of nutrients plays a key role in structuring plant communities. A theoretical model recently proposed by Lambers et al. (2008) postulates that in regions with very old and poor soils in P and N, the dominant species had a higher proportion of specializations and less root associations with mycorrhizal fungi. These regions were classified as OCBILs (ols, climatically buffered, infertile landscapes). This study aims to test this model and asses whether communities of rupestrian fields might be categorized as OCBILs by analyzing the chemical composition of soil, leaf stoichiometry and % mycorrhizal root colonization by the dominant species in six communities in the Espinhaço Range, Minas Gerais. We selected the ten most abundant species in each of areas distributed along a transect of 190 km, totaling 60 species. We evaluated the leaf attributes (concentration of N, P analysis of leaf mass per unit area and N:P ratio) and colonization of roots by micorrhiza. Chemucally, the soil of the rupestrian fields shows very low availability of P and N, comparable to other soils OCBILs (Western Australia and the Cape region in South Africa). The proportion of root colonization of plants by fungi was positively correlated with [P] soil of each community, supporting the Lambers model's on a regional scale. Species of rupestrian fields have a high N:P ratio leaf (average of 43 for all fields studied), higher than those found in other OCBILs, suggesting a strong limitation by phosphorus. We found average 183 gm.m-2 for LMA, 12,46 mg.g-1 and 0,36 mg.g-1 to P leaf. The results obtained suggests that rupestrian fields should also be classified as OCBILs, status wich would require greater attention to these fields still little studied and already threatened ecologicaly / Mestrado / Ecologia / Mestre em Ecologia

Les changements globaux, notamment les changements d'usage des terres, modifient profondément le fonctionnement des écosystèmes et la biodiversité et, ont déjà impacté de nombreux services écosystémiques. La disparition de ces écosystèmes souligne la nécessité de préserver les zones intactes, et la restauration des zones détruites ou perturbées peut permettre de venir en appui aux efforts de conservation et minimiser les dommages. Ce travail a pour objet d’étude les campos rupestres, des pelouses néotropicales d’altitude, faisant partie du Cerrado (savane brésilienne), qui recèlent une importante biodiversité et qui, comme bien d'autres écosystèmes de montagne, fournissent de précieux services écosystémiques tels que la filtration de l’eau. Ils ont été, et sont encore, grandement affectés par les activités humaines (les travaux de génie civil, les carrières ou les mines). Le premier objectif de cette thèse était de décrire l'écosystème de référence, afin de définir clairement un objectif de restauration et mesurer les progrès et le succès de la restauration. Nous avons montré que les campos rupestres sont composés d'au moins deux communautés végétales distinctes (une avec un substrat caillouteux et l’autre avec un substrat sableux), chacune ayant une composition en espèces et une structure particulières ainsi qu’une grande biodiversité. La phénologie reproductive varie au sein des communautés herbacées: la majorité des espèces fleurissent et fructifient pendant la saison des pluies, d'autres se reproduisent en revanche durant la saison sèche. Tout au long de nos 2 années de suivis phénologiques, certaines espèces dominantes, notamment des Poaceae, n'ont pas été observées en fleur impliquant une dispersion limitée de ces espèces vers les zones dégradées. Les communautés végétales de campos rupestres ne sont pas résilientes aux fortes perturbations: plusieurs années après, presque aucune des espèces cibles n’ont été trouvées en zones dégradées, les sols ont complètement été modifiés et les banques de graines ne se sont recomposées qu’avec des espèces rudérales non désirées. Selon le modèle des filtres, une communauté résulte d’un pool régional d’espèce sélectionné par un ensemble de filtres : de dispersion, abiotique et biotique. Les interventions de restauration mises en place avaient pour but d’agir sur ces différents filtres afin de diriger la dynamique des communautés végétales. Nous avons mis en place trois protocoles de restauration in-situ (le transfert de foin, la translocation d’espèce et la translocation de plaque de végétation) pour restaurer les deux types de communautés de campos rupestres identifiées. Le transfert de foin n’a pas permis la restauration des communautés végétales de campos rupestres en raison de l’importante altération des sols et, surtout, à cause de la mauvaise qualité des graines. En effet, nos études de germination ont montré que, alors que certaines espèces de Xyridaceae et Velloziaceae germent très bien, certaines espèces dominantes de Poaceae, de Cyperaceae ou d’Asteraceae ont des graines soit vides, soit non viables, soit dormantes ; le semis se révèle alors peu efficace. Nous n’avons pas mis en évidence d’effet positif du feu sur la germination des espèces de campos rupestres. La translocation d'espèces s’avère un succès pour une seule espèce, Paspalum erianthum. Pour les autres, les dommages causés au niveau des racines lors de la translocation limitent probablement leur survie. Enfin la translocation de plaques de végétation s’avère être la méthode la plus efficace permettant à de nombreuses espèces d’être réintroduites en zones dégradées. En raison de la faible résilience des campos rupestres dans lesquels les plaques de végétation ont été prélevées, cette méthode ne peut être envisagée que pour sauver des habitats dans le cas extrême où leur destruction est inévitable. Face à la difficulté de restaurer les campos rupestres, leur protection et leur conservation doit être une priorité / Global environmental changes, especially land-use changes, have profound effects on both ecosystem functioning and biodiversity, having already altered many ecosystem services. These losses emphasize the need to preserve what remains; however when conservation programs are not sufficient, restoring areas that have been destroyed or disturbed can improve conservation efforts and mitigate damages. This work focuses on campos rupestres, Neotropical grasslands found at altitudes, which are part of the Cerrado (Brazilian savannas). They host a great biodiversity with a high level of endemism and, like other mountain ecosystems, provide valuable ecosystem services, such as water purification and recreational services. They have been and still are being impacted by human activities, such as civil engineering construction, quarrying or mining. The first objective of this thesis was to describe the reference ecosystem in order to aim for a clear restoration target and to monitor progress and success. We show that campos rupestres are composed of at least two distinct plant communities (i.e. sandy and stony grasslands), each having a specific composition and structure, hosting a great biodiversity. Several phenological patterns occur among the herbaceous communities: the majority of species flowers and fruits appear during the rainy season but other patterns can be observed. During our 2-year survey, some dominant species belonging to Poaceae, among others, were not observed reproducing, which implies limited chances to disperse on degraded areas. Campo rupestre vegetation is not resilient following a strong disturbance: several years after the disturbance, almost no native species are encountered on the degraded areas, soils are completely altered and seed bank recomposes only with non-target ruderal species. According to the filter model, a local community is a subset of the regional species pool determined by a set of dispersal, abiotic and biotic filters. Acting on the different filters to influence the plant community was the core of our restoration interventions. We then applied three in-situ restoration protocols (hay transfer, species translocation and turf translocation) to restore both kinds of grassland. Hay transfer does not allow the restoration of campo rupestre vegetation because of soil alteration and mainly because of poor seed quality. Indeed, germination studies show that, while some Xyridaceae and Velloziaceae have a high germinability, some dominant Poaceae, Cyperaceae or Asteraceae species have embryoless, unviable or dormant seeds, which makes seeding less efficient. There is no evidence that fire-related cues enhance germination in campos rupestres. Species translocation is successful for only one species, Paspalum erianthum; for the others, root damages probably impede survival. Finally, turf translocation is the most successful method, since numerous species are re-introduced on degraded areas. However due to the low resilience of pristine campos rupestres where turfs are taken from, turf translocation can only be considered in the case of habitat rescue, in circumstances when complete habitat destruction is otherwise unavoidable. Face to the difficulty to restore these peculiar grasslands, the protection and the conservation of campos rupestres must be made a high priority

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2016-07-11T23:08:58Z No. of bitstreams: 1 Jumara Marques Souza_tese.pdf: 2615056 bytes, checksum: b21b8de1cf3cd6d4e050ce8ae830c183 (MD5) / Made available in DSpace on 2016-07-11T23:08:58Z (GMT). No. of bitstreams: 1 Jumara Marques Souza_tese.pdf: 2615056 bytes, checksum: b21b8de1cf3cd6d4e050ce8ae830c183 (MD5) Previous issue date: 2015-09-28 / Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq / Disturbances affect plant populations in different ways, and their understanding is extremely important to define management strategies and biodiversity conservation. Such disturbances may be natural, as in the case of fire initiated by lightning, or can be anthropogenic, as the extraction of natural products. In both cases, populations of plants under interference from disturbances may increase or decrease, being necessary to understand its effects on populations in the long run. A key plant for conservation is Vellozia aff. sincorana L.B.Sm. & Ayensu (Velloziaceae), is an important species for the conservation of rupestrian fields of the western portion of the Serra do Sincor?, which is endemic. The largest area of distribution of this species, popularly know as candomba, is within the limits of the Chapada Diamantina National Park (CDNP), Bahia, Brazil, where it has a elevated cover. Candomb? branches are target of extraction in the region, which are destined to ignite wood stoves. In addition to this anthropic disturbance, V. aff. sincorana is also frequently affected by fires, which despite being a natural phenomenon are largely generated by human activity in CDNP. The fire has a marked effect on V. aff. sincorana, as it stimulates their mass flowering and synchronic, with no registration of flowering in this species in the absence of fire. This study evaluated the effects of fire in individuals of V. aff. sincorana in space and stages structure and the population dynamics of this species. In addition, simulations were performed with different frequencies fire, harvest intensities, and the association of fire and harvesting in order to assess the possibilities of using fire as management tool of harvest to this species. For analyzes involving harvest, the two techniques used by candomb? collectors in the region (removal of whole adult plants or branches) were simulated. For this study, individuals of V. aff. sincorana were marked, measured and monitored on 16m? plots over two censuses (2012 and 2013) in six populations, three unaffected by fire since 2008, and three affected by recent fires (2011 or 2012), approximately 40 days before the first census. In total, we monitored 1,617 individuals in 56 plots. The results showed that the recent fire affects individuals of V. aff. sincorana stimulating flowering and increases in canopy area, plant height and number of rosettes. Populations had lower rates of mortality and recruitment, however, in areas without recent fire, both the recruitment by seeds and mortality of juveniles were higher. The distribution of individuals was aggregate in all populations, averaging two individuals per m?. The recent fire caused changes in distribution of individuals in class of life stages. In general, populations tended to have higher concentration of adults. The reproduction stimulus by fire increases fertility and causes growth of recent fire populations, so the recent fire encourages population increase of V. aff. sincorana, while in absence of fire populations tended to decrease. The simulation results showed that populations of V. aff. sincorana tend to decrease with increasing the gap between the fire events. In harvest simulations, the growth of population was negatively affected by the decrease in harvest intervals and no fire. The results showed that the harvesting technique of whole adult is not sustainable and that the maintenance of the populations of V. aff. sincorana depends on the survival of individuals, mostly adults. In general, we find evidence that the conservation of V. aff. sincorana and its management for extractive purposes depend on periodic fire occurrence. / Os dist?rbios afetam as popula??es vegetais de diversos modos, sendo sua compreens?o de extrema import?ncia para defini??o de estrat?gias de manejo e conserva??o da biodiversidade. Tais dist?rbios podem ter origem antr?pica ou n?o, a exemplo do fogo iniciado por raio e da extra??o de produtos naturais. Em ambos os casos, as popula??es de plantas sob interfer?ncia podem crescer ou diminuir demasiadamente, sendo necess?ria a compreen??o dos efeitos em longo prazo dos dist?rbios nas popula??es. Vellozia aff. sincorana L.B.Sm. & Ayensu (Velloziaceae) ? uma esp?cie importante para a conserva??o dos campos rupestres da por??o ocidental da Serra do Sincor?, da qual ? end?mica. A maior ?rea de distribui??o dessa esp?cie, popularmente conhecida como candomb?, encontra-se dentro dos limites do Parque Nacional da Chapada Diamantina (PNCD), Bahia, Brasil, onde apresenta uma elevada cobertura. Os ramos do candomb? s?o alvo de extrativismo na regi?o, os quais s?o destinados a acender fog?es a lenha. Al?m desse dist?rbio antr?pico, V. aff. sincorana tamb?m ? frequentemente afetada por inc?ndios, que apesar de serem um fen?meno natural, s?o majoritariamente originados pela a??o humana no PNCD. O fogo tem um efeito marcante sobre V. aff. sincorana, j? que estimula sua flora??o em massa e sincr?nica, n?o havendo registros de flora??o da esp?cie na aus?ncia de fogo. O presente estudo avaliou os efeitos do fogo nos indiv?duos de V. aff. sincorana, na estrutura espacial e de est?dios, bem como na din?mica populacional dessa esp?cie. Al?m disso, foram realizadas simula??es com diferentes frequ?ncias de fogo, intensidades de colheita, e da associa??o entre fogo e colheita, a fim de avaliar as possibilidades do uso do fogo como ferramenta do manejo extrativista dessa esp?cie. Para as an?lises envolvendo colheita, foram simuladas as duas t?cnicas utilizadas pelos coletores de candomb? na regi?o (retirada de plantas adultas inteiras ou a de ramos). Para esse estudo, os indiv?duos de V. aff. sincorana foram marcados, medidos e acompanhados em parcelas de 16m? durante dois censos (2012 e 2013) em seis popula??es, tr?s n?o afetadas por fogo desde 2008, e tr?s afetadas por inc?ndios recentes (2011 ou 2012), aproximadamente 40 dias antes do primeiro censo. No total, foram acompanhados 1.617 indiv?duos distribu?dos em 56 parcelas. Os resultados evidenciaram que o fogo recente afeta os indiv?duos de V. aff. sincorana estimulando ? flora??o e aos incrementos em ?rea da copa, altura da planta e produ??o de rosetas. As popula??es apresentaram baixas taxas de mortalidade e recrutamento, por?m, nas ?reas sem fogo recente, tanto o recrutamento via sementes quanto a mortalidade de juvenis foram maiores. A distribui??o dos indiv?duos foi agregada em todas as popula??es, com m?dia de dois indiv?duos/m?. O fogo recente provocou mudan?as na distribui??o dos indiv?duos entre as classes de est?dios de vida. Em geral, as popula??es tenderam ? maior concentra??o de adultos. A reprodu??o estimulada por fogo aumenta a fertilidade e ocasiona crescimento das popula??es rec?m-incendiadas, de modo que o inc?ndio recente favoreceu o aumento populacional de V. aff. sincorana, enquanto na sua aus?ncia as popula??es tenderam ? diminui??o. Os resultados das simula??es evidenciaram que as popula??es de V. aff. sincorana tendem ? diminui??o com o aumento do intervalo entre os eventos de fogo. Nas simula??es de colheita, o crescimento das popula??es foi afetado negativamente pela diminui??o dos intervalos de colheita e aus?ncia de fogo. Os resultados evidenciaram que a t?cnica de colheita de adultos inteiros n?o ? sustent?vel e que a manuten??o das popula??es de V. aff. sincorana depende da sobreviv?ncia dos indiv?duos, principalmente os adultos. De modo geral, encontramos ind?cios de que a conserva??o de V. aff. sincorana e seu manejo para fins extrativistas dependem da ocorr?ncia peri?dica do fogo.