Árvores e variáveis ambientais influenciam a regeneração natural de uma floresta estacional decidual no Brasil Central (original) (raw)
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Acta Botanica Brasilica, 2013
Th e aim of this work was to evaluate the fl oristic composition, richness, and diversity of the upper and lower strata of a stretch of mixed rain forest near the city of Itaberá, in southeastern Brazil. We also investigated the diff erences between this conservation area and other stretches of mixed rain forest in southern and southeastern Brazil, as well as other nearby forest formations, in terms of their fl oristic relationships. For our survey of the upper stratum (diameter at breast height [DBH] ≥ 15 cm), we established 50 permanent plots of 10 × 20 m. Within each of those plots, we designated fi ve, randomly located, 1 × 1 m subplots, in order to survey the lower stratum (total height ≥ 30 cm and DBH < 15 cm). In the upper stratum, we sampled 1429 trees and shrubs, belonging to 134 species, 93 genera, and 47 families. In the lower stratum, we sampled 758 trees and shrubs, belonging to 93 species, 66 genera, and 39 families. In our fl oristic and phytosociological surveys, we recorded 177 species, belonging to 106 genera and 52 families. Th e Shannon Diversity Index was 4.12 and 3.5 for the upper and lower strata, respectively. Cluster analysis indicated that nearby forest formations had the strongest fl oristic infl uence on the study area, which was therefore distinct from other mixed rain forests in southern Brazil and in the Serra da Mantiqueira mountain range.
Floristic, Diversity and Spatial Distribution of Tree Species in a Dry Forest in Southern Brazil
Applied Ecology and Environmental Research, 2017
This study was conducted in a fragment of deciduous seasonal forest (DSF), located between the municipalities of Piratuba and Ipira, Santa Catarina. The objective was to evaluate the floristic composition and the successional stage through the ecological groups, the Shannon diversity index (H') and the dispersal syndromes of species, also using the H' and the McGinnies index (IGA) to determine the pattern of spatial distribution of species. 14 transects were installed, each with 1,000 m 2 , considering all trees with Diameter at Breast Hight (DBH) ≤ 4.0 cm. In total, 2,125 individuals were sampled, belonging to 113 species and 34 families. Myrtaceae and Fabaceae were the families with the highest species richness, with 14.2% and 11.5%, respectively. Euphorbiaceae and Lauraceae added approximately 25% of the individuals. The most abundant species were Actiniostemon concolor (Spreng.) Müll. Arg (6.9%) and Luehea divaricata Mart. (6.7%). The ecological group of the pioneers totaled 40% of the individuals and 36.3% of the species. The zoochoric syndrome accounted for just over 60% of individuals and species. The H' was 3.92 nats. ind-1 and the Pielou evenness (J) was 0.82. The IGA revealed that only over 40% of the species and 60% of the individuals showed a clumped dispersion pattern. The community is on successional transition phase, from the initial to the intermediate stage. In this scenario, management measures adopted for the microscale could be implemented in order to preserve this important repository for diversity. The application of McGinnies index can be of great use in conservation and forest management, as its interpretation may contribute to the development of restoration methods of degraded areas, enrichment of forest remnants, germplasm conservation and other activities.
Brazilian Decidual Tropical Forest enclaves: floristic, structural and environmental variations
Brazilian Journal of Botany, 2017
Several theories have been proposed to explain the raised richness and diversity of species in native tropical forests, with an emphasis on those that invoke the niche characteristics. In the present study, we sample the woody vegetation in four enclaves of Deciduous Forests and investigate whether environmental variables can explain the floristic and structural differences among the sampled fragments. The studied areas are located the ''Cerrado'' biome core zone and in ''Cerrado''-Atlantic Forest and ''Cerrado-Caatinga'' transition zones. The woody vegetation (diameter at breast height-DBH C 5 cm) was sampled in 100 plots of 20 9 20 m, 25 plots in each enclaves. The investigated environmental variables were chemical and textural properties of the soil, rockiness, declivity and altitude. We found significant differences for the floristic variables (richness, diversity), among all the environmental variables, as well as for the density, height and for the DBH first class. We noticed strong influence of the environmental variables, and the nutrients availability, texture, soil acidity and the land relief are the most responsible for the floristic-cultural difference. We propose that the gradient existence of rainfall has influenced the edaphic characteristics, creating variations in the habitats, which may have favored the arrival and establishment of different species in each study area and the distinctive development of the woody vegetation at the enclaves to the Deciduous Forest.
Rodriguésia
Tropical forests are one of the most important ecosystems and loss of biological diversity in these is a major concern. We studied seven forest remnants on the coast of Rio de Janeiro, southeastern Brazil, three medium-sized (24-63 ha) and four small (5-11 ha), to assess the influence of size, degree of disturbance and isolation on composition and diversity of the tree layer. A total of 443 species in 60 families and 185 genera were recorded, with Myrtaceae, Lauraceae and Fabaceae being the most species-rich families. The results showed areas of high α-diversity (α= 34.86-75.69) and a slightly greater decline of similarity with distance between the study areas. Remnant size not explained the variation in the species composition and we found correlation between the level of disturbance and the floristic composition. The remnants had low floristic similarity, strongly influenced by the degree of disturbance. Results suggest that disturbance influences composition and diversity and con...
Diversity and Structure of Natural Regeneration in Swamp Forests in Southeastern Brazil
Floresta e Ambiente
Many factors can influence the structures and distributions of plant communities. Plant diversity of swamp forests reflect responses to water stress conditions. We evaluated the floristic diversity, structure, and composition of the regenerating shrub-tree species of six swamp forests in veredas ecosystems (northern Minas Gerais, Brazil), and the floristic similarities between them. All individuals ≥ 1 cm in diameter at ground level and < 3 cm in diameter at breast height were sampled in one hundred 25 m 2 plots in each area. A total of 5442 individuals were recorded, distributed among 134 species, 85 genera, and 47 botanical families, with a diversity (Shannon) of 3.38 and equability (Pielou) of 0.69. Beta diversity was high, while similarities between the areas were low, with only two species common to all six sites. The forests showed different compositions, diversities, and natural regeneration structures, reflecting their ecotone nature and past anthropic impacts.
Aims Understanding succession in tropical forest is an important aspect of vegetation science, but to date, successional processes in seasonally dry tropical forests (SDTFs) have received much less attention than evergreen humid tropical forests. We aim to fill this knowledge gap. Methods We investigated vegetation succession in SDTF areas consisting of three different successional stages (early, intermediate, late), and a SDTF-savanna ecotone in the municipal district of Juramento, north of Minas Gerais State, Brazil. Using twelve 400 m2 plots in each area, we compared vegetation parameters and structural variables (absolute density and basal area), and examined the floristic composition of the tree component to find gradients of change. Important Findings We found evidence of species turnover along a successional gradient, with the intermediate stage showing the highest species richness and diversity. This was accompanied with a significant increase in the number of tree individuals and basal area from the early to intermediate successional stage. However, the intermediate and late SDTF successional stages were more similar in structure and floristics. The ecotone was the most species rich, and was similar to the intermediate SDTF and early successional stage in species richness and floristic composition respectively. These results will have implications for guiding SDTF management and recovery programs.
REVISTA AGRO@MBIENTE ON-LINE
Understanding secondary forest structure and functioning is essential for future planning of effective use and/or recompositioning of such areas. The secondary succession process is influenced by the characteristics of componente species, their interaction with other species and with abiotic components. Thus, the objective of the current study was to evaluate the vegetation structure, dispersion syndromes and pollination of a secondary forest fragment with 5 years of regeneration in the Atlantic Forest landscape of Pernambuco, northern Brazil. A total of 30 permanent 10 x 10 m plots with 10 m separations were used for canopy sampling (i.e., all woody individuals with stem diameter at 1.30 m (DBH) greater than 5 cm. Floristic composition analysis recorded 32 species from 21 families. Absolute density was 150 individuals with basal area of 4.787 m² ha-1, and the Shannon-Weaver index (H ‘) was 2.960. The family with the highest number of species was Melastomataceae, while those with gr...
Revista Brasileira de Botânica, 2004
-(Diversity and structure of the tree community of a fragment of tropical secondary forest of the Brazilian Atlantic Forest domain 15 and 40 years after logging). Two adjacent tracts of tropical secondary forest, situated in Itambé do Mato Dentro, southeastern Brazil, which had been regenerating for 15 and 40 years after clearing, were compared with the purpose of detecting differences in species diversity and composition, species guild composition (regeneration, stratification and dispersion), and stand structure. Four and three 1,125 m 2 plots laid on the 15-and 40-year-old stands, respectively, sampled 2,430 trees with diameter at the base of the stem ≥ 5 cm. The number of species (S = 199) was high for this forest type and significantly higher for the older stand. Tree density was significantly higher in the younger stand, particularly for smaller trees, whereas the two stands did not differ in both basal area and volume per hectare. Trees of shade-tolerant and understory species were significantly more abundant in the older stand. Though sharing a large proportion of species (49%), the two stands differed significantly in the abundance of many species. Live stumps probably contributed to the relatively quick restoration of some forest characteristics, particularly species diversity, basal area and volume. Key words-Brazilian Atlantic forest, forest regeneration, succession, tropical secondary forest RESUMO-(Diversidade e estrutura da comunidade arbórea de um fragmento de floresta tropical secundária do domínio da Floresta Atlântica 15 e 40 anos após o corte). Dois trechos adjacentes de floresta secundária, situados em Itambé do Mato Dentro, MG, e que estiveram em regeneração por 15 e 40 anos depois do corte foram comparados com o propósito de detectar diferenças em diversidade e composição de espécies, composição de guildas (regeneração, estratificação e dispersão) e estrutura do povoamento. Quatro e três parcelas de 1.125 m 2 foram distribuídas nos povoamentos de 15 e 40 anos de idade, respectivamente, e amostraram 2.430 árvores com diâmetro na base do tronco ≥ 5 cm. O número de espécies (S = 199) foi alto para essa tipologia florestal e significativamente maior para o povoamento mais velho. A densidade de árvores foi significativamente mais alta no povoamento mais jovem, particularmente para árvores menores, ao passo que os dois povoamentos não diferiram em área basal e volume por hectare. Árvores de espécies tolerantes à sombra e de espécies de subbosque foram significativamente mais abundantes no povoamento mais velho. Apesar de compartilharem uma grande proporção de espécies (49%) os dois povoamentos diferiram significativamente quanto à abundância de muitas espécies. As cepas das árvores provavelmente contribuíram para a relativamente rápida restauração de algumas características da floresta, particularmente diversidade de espécies, área basal e volume. Palavras-chave-Floresta Atlântica, floresta secundária tropical, regeneração florestal, sucessão
Acta Botanica Brasilica, 2011
We assessed the structure, diversity and distribution of tree species in a 10.24-ha permanent plot of high Restinga forest (HRF) in southeastern Brazil. We sampled 15,040 individuals belonging to 45 families, 87 genera and 116 species (density= 1,468 trees ha-1, and basal area= 28.0 m² ha-1). Mean richness was lower than other types of tropical forests and other HRFs that have been less intensively sampled, which is probably due to the younger age and hydromorphy of the soils in the study site. Tree density, basal area, species composition, and diversity all varied considerably depending on the size class considered. The studied plot had a density similar to other tropical forests but with a smaller basal area (fewer individuals > 60 cm in diameter), and higher density of smaller trees. Multi-stemmed individuals were not frequent (11% of the trees), though they were widespread among species (74% of the species). Spatial distribution was predominantly clumped, a pattern common to ...