RESUMO -(Regeneração de espécies nativas lenhosas sob plantio de Eucalyptus em área de Cerrado na Floresta Nacional de Paraopeba, MG, Brasil). A regeneração de sub-bosques em plantios homogêneos tem estreita dependência de florestas vizinhas. Outros fatores exercem influência, como a ecologia da dispersão da espécie, os efeitos de borda e clareiras. Diante disto, procurou-se conhecer a florística e a estrutura da vegetação lenhosa de espécies nativas sob plantio de Eucalyptus em área de Cerrado na Floresta Nacional de Paraopeba, MG, e verificar a variação da riqueza, da densidade e de indivíduos zoocóricos e anemocóricos da borda para o interior do talhão. Para tal, foram alocadas cinco parcelas de 5×40 m, subdivididas em parcelas 5×10 m. Foram encontradas 47 espécies e destas as que se destacaram foram Magonia pubescens A. St.-Hil.e Miconia albicans (Sw.) Triana, principalmente quanto à alta densidade. Das espécies amostradas 53% possuem dispersão zoocórica e 43% anemocórica. Verificou-se também a diminuição da riqueza, da densidade e da percentagem de indivíduos anemocóricos da borda para interior. Porém a percentagem de indivíduos zoocóricos aumentou no interior do talhão. A maior riqueza e densidade na borda dá-se pela dificuldade da dispersão de diásporos no interior do fragmento. O índice de diversidade (H'= 2,49) encontrado para este estudo foi próximo aos valores observados em estudos em regeneração sob Eucalyptus em áreas de Cerrado.Palavras-chave: dispersão, unidade de conservação, fitossociologia, composição florística e regeneração ABSTRACT -(Regeneration of wood natives species under Eucalyptus stand of Cerrado area in the Floresta Nacional of Paraopeba, Minas Gerais, Brazil). The regeneration of understory in homogeneous stands is closely dependent of neighbour forests. Others factures also have influency such as the species dispersion ecology, the border effects and clearings. Therefore, the objective of this work were to study the floristic and structure of native woody plant species growing under stands of Eucalyptus in the Cerrado area in the Flona (Floresta Nacional -National Forest) of Paraopeba, Minas Gerais, Brazil, and to determine the variations in richness, density and the zoochorous and anemochorous individual dispersions from the borders into the stand. To carry out this study five plots with 5×40 m, subdivided into subplots of 5×10 m were set up. A total of 47 species were found and among these two stood out mainly because of their high density: Magonia pubescens A. St.-Hil and Miconia albicans (Sw.) Triana. From the species sampled 53% have a zoochorous dispersion and 43% have an anemochorous dispersion. The decrease in richness, density and anemochorous dispersion species from the border into the stand were also observed. However the percentage of zoochorous dispersion individuals increase inside the stand. The large richness and density on the borders is due the propagule dispersion difficulty inside the fragment. The diversity index (H'=2.49) found in this study was close to the v...

This study investigated the influence of soil factors on the structure, richness and distribution of woody Cerrado species within the National Forest of Paraopeba, Minas Gerais State, Brazil. Individuals with basal stem circumference $ 10 cm were sampled in five plots of 20 3 100 m. The study was conducted in five environments with different physiognomies and types of soils. A total of 132 species were recorded. The species with the greatest importance values varied between different areas, as did structure. Canonical correspondence analysis ordination showed three different groups closely related to soil fertility and Al levels. These relations were also confirmed by Pearson's correlation where richness was positively related to pH, K, Ca, Mg and P and negatively to Al. The basal area was positively correlated with levels of P, Mg, Ca and T (base saturation) and negatively with Al, also using Pearson's correlation. Likewise, density was positively correlated with Mg and negatively with Al. The analysis shows that soil fertility and the concentration of Al are two of the most important factors responsible for structural and floristic variation and for differentiating dystrophic and mesotrophic Cerradão.

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Vegetation and soil properties of an iron-rich canga (laterite) island on the largest outcrop of banded-iron formation in Serra de Carajás (eastern Amazonia, Brazil) were studied along a topographic gradient (738-762 m asl), and analyzed to test the hypothesis that soil chemical and physical attributes play a key role in the structure and floristic composition of these plant communities. Soil and vegetation were sampled in eight replicate plots within each of the four vegetation types. Surface (0-10 cm) soil samples from each plot were analyzed for basic cations, N, P and plant species density for all species was recorded. CCA ordination analysis showed a strong separation between forest and non-forest sites on the first axis, and between herbaceous and shrubby campo rupestre on the second axis. The four vegetation types shared few plant species, which was attributed to their distinctive soil environments and filtering of their constituent species by chemical, physical and hydrological constraints. Thus, we can infer that Edaphic (pedological) factors are crucial in explaining the types and distributions of campo rupestre vegetation associated with ferruginous ironstone uplands (Canga) in Carajás, eastern Amazonia, therefore the soil properties are the main drivers of vegetation composition and structure on these ironstone islands.

Acta bot. bras. 24(3): 734-746. 2010. IntroduçãoO ecossistema Restinga, no sentido geomorfológico, é a paisagem Quaternária arenícola marítima, que desde Ule (1901) e Dansereau (1947) já se distinguia dos litorais rochosos (costões) e lamosos (Manguezais), que formam o conjunto de formas costeiras do Brasil. Após as praias, inicia-se o ecossistema de Restinga com as primeiras dunas fi xas, estendendo-se com amplitude variável até os Tabuleiros Costeiros do grupo Barreiras ou escarpas de embasamento Cristalino.Os solos dos cordões mais internos ao continente são mais antigos, possuem maior altitude (6 a 8 m), maior teor de matéria orgânica no solo, maior impregnação de ácidos húmicos e seus sedimentos arenosos são em geral superficialmente brancos; já os solos dos cordões mais externos apresentam-se com coloração mais amarelada, pouca impregnação de ácido húmico e possuem menor altitude (4 a 5 m) (Martin et al. 1997). Sobre os cordões, localizam-se as formações não inundáveis de Restinga, ou seja, áreas sem infl uência direta do lençol freático. Nas áreas de intercordões, ocorrem terrenos topografi camente mais baixos, originadas da sedimentação parcial ou total de lagunas e/ ou paleo-lagunas, apresentando por isso áreas inundadas ou inundáveis, tendo um solo síltico e/ou areno-argilosos, mais ricos em matéria orgânica (Martin et al. 1997).Alguns trabalhos trazem alguma informação sobre os fatores edáfi cos como determinantes nas formações de Restinga. Fabris (1995) ABSTRACT -(Phytophysiognomic-edaphic gradient of forest formations in restinga areas of southeastern Brazil). This research aimed to evaluate the phytophysiognomic variations in four forest formations related to fl ood gradient and edaphic characteristics. The study was carried out at the Jacarenema Nautral Municipal Park, Vila Velha, Espírito Santo state, Brazil. We made four soil profi les varying in depth, and collected one sample from each horizon per profi le. Piezometers were set up at 2m depth in each phytophysiognomy to record groundwater variance. Recognition and delimitation of the vegetation units followed the phytophysiognomic, ecological and fl oristic criteria of the different formations, and vegetation characteristics of each phytocenose were expressed by means of an illustrative profi le. Four distinct classes of soil were found beneath the phytophysiognomies. Very poorly drained Histosol (Thionic, Sapric, Solodic) was found beneath the Flooded Forest, poorly drained Gleysol (Thionic, Humic, Solodic) beneath the Seasonally Flooded Forest, moderately to imperfectly drained Spodosol (Humiluvic, Hydromorphic, Duric) beneath the Non-Flooded Transitional Forest, and excessively drained Quartzarenic Entisol (Orthic, Spodic) beneath the Non-Flooded Forest. It is evident from the outcome that there are indeed vegetation responses to edaphic variables.