445 resultados para Cerrado sensu lato

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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O presente trabalho foi realizado em uma área remanescente de CerradoSensu Lato” dentro do espaço que abriga a Escola do Meio Ambiente - EMA, localizada no município de Botucatu, interior do Estado de São Paulo. O objetivo principal do mesmo foi o estudo e descrição dos tipos de frutos e sementes, e respectivas síndromes de dispersão das espécies ali presentes. As coletas foram feitas através do método de caminhamento, no período de abril a novembro de 2009. As espécies em frutificação tiveram seus frutos coletados e suas características registradas. A classificação dos frutos foi feita a partir da textura (carnoso ou seco) e quanto à deiscência (deiscente ou indeiscente). Foram analisadas 41 espécies, escolhidas a partir do levantamento preliminar feito na área. O modo de dispersão predominante foi a autocoria, embora secundariamente muitas espécies se dispersem por anemocoria, por se tratar de uma região aberta onde os ventos são constantes. A dispersão por zoocoria também foi significativa, o que pode estar associado à abundância e diversidade de espécies de animais observadas no local

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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O Cerrado ainda recebe pouca atenção no que diz respeito à ornitologia embora seja a única savana tropical do mundo considerada um hotspot de biodiversidade. O cerradão é uma das fisionomias menos conhecidas e mais desmatadas do bioma e poucos levantamentos avifaunísticos foram realizados nessas florestas. Para revisar os estudos sobre aves de cerradão e complementar os poucos inventários já existentes realizados nesse tipo florestal no estado de São Paulo, foi realizado um levantamento bibliográfico dos estudos publicados sobre aves de cerradão. Adicionalmente foi conduzido um levantamento das aves de um fragmento de cerradão de 314 ha localizado na região central do estado de São Paulo, Brasil, entre setembro de 2005 e dezembro de 2006 com a utilização de transecções lineares com raio ilimitado de detecção. de 95 estudos envolvendo aves de cerradão, apenas 17 (18%) discriminaram espécies registradas dentro desta fisionomia daquelas que obtiveram registros em outros ambientes de Cerrado. Exceto por um estudo, nenhuma outra investigação encontrou mais de 64 espécies de aves neste ambiente, resultado compartilhado com diversas regiões do Brasil e também da Bolívia. Diferenças no número de espécies entre cerradões não puderam ser atribuídas à degradação dos ambientes estudados ou tamanho de fragmento. Considerando os registros de cerradões no Brasil e na Bolívia, a compilação de dados acumulou 250 espécies distribuídas em 36 famílias e 15 ordens. Durante nossos trabalhos de campo em localidade do interior paulista foram registradas 48 espécies distribuídas em 20 famílias, incluindo o fruxu-do-cerradão (Neopelma pallescens), ameaçada em São Paulo, e o soldadinho (Antilophia galeata), quase ameaçada no estado e endêmica do Cerrado. Dentre as espécies mais abundantes no fragmento, nenhuma delas é ameaçada ou endêmica do bioma.

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Seven populations (six in culture and one sampled directly from nature) of the freshwater red algal families Batrachospermaceae, Lemaneaceae and Thoreaceae were examined, involving three species of Batrachospermum, two of Paralemanea and one of Thorea. All 'Chantransia' stages ultimately produced juvenile gametophytes. The production of juvenile gametophytes in the three populations of Batrachospermum was generally most abundant at 15°C and low irradiances (47-68 μmol photons m-2 s-1). The most abundant gametophyte development in the Paralemanea species was observed at 10°C and low or high irradiances (47-142 μmol photons m-2 s-1). Gametophyte production in Thoreaceae occurred at higher temperatures (20°C) and also at low irradiances. In species of the Batrachospermaceae and Lemaneaceae, the 'elimination cells' can be situated on the basal or suprabasal cell of the juvenile gametophyte, but the position is usually fixed in individual species. The presence and position of the elimination cells remain to be established in Thoreaceae. Our results corroborate a previous study suggesting that the position of elimination cells is such a constant feature that it is of potential diagnostic value at the generic or infrageneric (sectional or specific) level. The characteristics observed in the development of the juvenile gametophytes in species of Batrachospermaceae and Lemaneaceae essentially agreed with general descriptions in the previous studies. The characteristics of the Thoreaceae, with a distinctive developmental pattern of the juvenile gametophyte and the occurrence of two morphological types in the 'Chantransia' stage, support the proposal to elevate it to the ordinal level. Two remarkable observations in Batrachospermum species were the production of numerous juvenile gametophytes from filaments of the same plant of the 'Chantransia' stage and the formation of a system of rhizoidal filaments or cell agglomeration of the juvenile gametophytes, which produced new gametophytes. These two characteristics potentially increase the formation of additional gametophytes under favourable conditions.

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Fourteen culture isolates of freshwater acrochaetioid algae from distinct regions around the world were analysed, including the reddish species Audouinella hermannii, the dubious blue-greenish species A. pygmaea, and Chantransia stages from distinct taxonomic origins in the Batrachospermales sensu lato (Batrachospermaceae, Lemaneaceae and Thoreaceae). Four isolates (two 'Chantransia' stages and two species of Audouinella, A. hermannii and A. pygmaea) were tested under experimental conditions of temperature (10-25°C), irradiance (65 and 300 μmol photons m-2 s-1) and photoperiod (16:8 h and 8:16 h light/dark cycles). Plant colour is proposed as the only vegetative character that can be unequivocally applied to distinguish Audouinella from 'Chantransia', blue-greenish representing Chantransia stages and reddish applying to true Audouinella species (also forming reproductive structures other than monosporangia, e.g. tetrasporangia). Some isolates of A. pygmaea were proven to be unequivocally 'Chantransia stages owing either to production of juvenile gametophytes or to derivation from carpospores. No association of the morphology of A. pygmaea was found with any particular species, thus it should be regarded as a complex involving many species of the Batrachospermales sensu lato, as is also the case with A. macrospora. We therefore recommend that all blue-greenish acrochaetioid algae in freshwater habitats be considered as Chantransia stages of members of the Batrachospermales, and that the informal descriptors pygmaea and macrospora be used to distinguish the two discernable morphologies. Induction of gametophytes occurred under much wider conditions than previously reported, reinforcing the conclusion that requirements are probably species-specific. Although phenotypic plasticity was in evidence, with temperature, irradiance and photoperiod affecting morphology, no alga showed variation outside the limits based on traditional taxonomic studies. No overall trend was observed for vegetative or reproductive characters in response to temperature, irradiance and photoperiod for all the algae tested, only for specific algae or characters. Effects of temperature and irradiance on morphological characters were more evident, as well as strong interactions between these variables, whereas few differences were generally found in response to photoperiod and irradiance.

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The Cerrado (Brazilian savanna) has suffered massive destruction in recent years, mainly due to the expansion of agricultural areas. Many remnants of this vegetation are still poorly studied. Therefore, the purpose of this study was to carry out a floristic survey in a remnant of Cerrado in the municipality of Pratânia, central-west region of state of São Paulo, southeastern Brazil. In total, 120 species (38 families, 88 genera) were registered. The families with greater richness were: Fabaceae (23 species), Asteraceae (15), Myrtaceae (10), Malpighiaceae and Rubiaceae (seven each) and Bignoniaceae (five). The shrub component was predominant in the study area representing 37.5% of the recorded species. A comparison among eight Cerrado areas showed greater similarity between areas with similar altitude. © 2010 Check List and Authors.

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The objectives of this study were to characterize the floristic and to calculate the phytosociological parameters of species present in the areas of 'campo sujo' and 'cerrado' sensu stricto in the Ecological Station of Pirapitinga, Minas Gerais state (ESEC). For the floristic and phytosociologic survey, a total of 190 plots of 100 m2 each were allocated, where all the individuals with circumference at soil level (CSL) ≥ 16 cm in areas of 'campo sujo' and 'cerrado' sensu stricto were sampled. The parameters of frequency, density, dominance, and importance values and Shannon and Pielou indexes were calculated. The floristic similarity between areas was determinated by Sorensen index. In the study areas, a total of 3,224 individuals distributed in 81 species, 70 genera and 40 families were sampled. The richest families were Vochysiaceae and Fabaceae. The cerrado sensu stricto was the vegetal formation with the highest richness of species (81) and highest density (2.257 ind ha-1). Both areas have studied with high diversity and ecological dominance and have low diameter distribution in the form of inverted-J, indicating the predominance of young individuals.

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We analyzed the differences between irrigated and non-irrigated plants of three congeneric Styrax species that present distinct distribution patterns in the physiognomies of the Cerrado vegetation in Brazil. Styrax ferrugineus showed a stomatal conductance (gs) unresponsive to soil water deficit in potted plants. This may explain the high gas exchange and photochemical efficiency found in this species, which is well adapted to the Cerrado sensu stricto (s. str.), a savanna-type vegetation. S. camporum, which is widely distributed in the Cerrado sensu lato (s. l.) areas, was the only species that exhibited increased intrinsic water use efficiency on the days of maximum water deficit. This result distinguishes S. camporum from S. pohlii, which is a forest species, since the gs of both species decreased during the days of maximum water stress. In contrast to other studies, we propose that instantaneously measured traits, such as leaf gas exchange rates and chlorophyll fluorescence, may be used to detect non-plastic performances in response to environmental stress, helping explain distinct geographical distributions of congeneric species in the Cerrado vegetation. © 2013 Springer-Verlag Berlin Heidelberg.

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Pós-graduação em Ciências Biológicas (Biologia Celular e Molecular) - IBRC