Daniel Costa de Carvalho

Influence of environmental variation on Atlantic Forest tree-shrub-layer phytogeography in southeast Brazil

O presente trabalho analisou dados de 32 remanescentes florestais nos estados do Rio de Janeiro e Sao Paulo, atraves de analises multivariadas para responder a pergunta: Existem padroes floristicos do estrato arboreo-arbustivo da Floresta Atlântica relacionados a Serra do Mar e alargamento das planicies costeiras nos estados do Rio de Janeiro e Sao Paulo? Foram utilizadas tres analises multivariadas para investigar as relacoes entre a flora arboreo-arbustiva e a variacao ambiental das 32 areas. As analises demonstraram influencia de alteracoes geo-climaticas sobre a diferenciacao floristica das especies arboreas e arbustivas da Mata Atlântica. Este fato permitiu gerar grupos com as areas analisadas baseados em caracteristicas bioticas e abioticas, sustentando a existencia de padroes floristicos nos estados do Rio de Janeiro e Sao Paulo. Os grupos formados refletem a substituicao das especies arboreo-arbustivas entre as areas analisadas como consequencia de variacoes da precipitacao, altitude e temperatura media anual a medida que modifica o posicionamento da Serra do Mar e cresce a planicie costeira. Para cada grupo foram designadas especies preferenciais que devem ser consideradas em programas de restauracao e conservacao das regioes fitoecologicas por eles representadas.

Estrutura e florística do estrato arbóreo no cerrado sensu stricto de Buritis, Minas Gerais, Brasil

( Estrutura e floristica do estrato arboreo no cerrado sensu stricto de Buritis, Minas Gerais) . A crescente perda de cobertura do cerrado sensu stricto vem demandando mais estudos sobre sua ecologia para auxiliar em sua conservacao. Este estudo caracteriza a composicao floristica e estrutural do estrato arboreo de um cerrado sensu stricto e testa sua similaridade a outros locais com fisionomia similar. Atraves de parcelas, foi amostrada uma area de 1,45 ha, registrando-se individuos com DAS ≥ 10 cm. Foram calculados os parâmetros estruturais, indice de Shannon (H’), equitabilidade de Pielou (J’) e analisada a distribuicao de especies em classes de diâmetro, enquanto a distribuicao de individuos, em classes de altura e diâmetro. O estudo foi comparado a nove cerrados sensu stricto atraves da analise de similaridade. Registrou-se 1155 individuos, 90 especies, 73 generos e 37 familias. H’ foi igual a 3,75 e J’ igual a 0,83. Qualea grandiflora, Magonia pubescens, Curatella americana e Qualea parviflora apresentaram os maiores valores de importância. A densidade foi 796 individuos/ha e a area basal somou 11,87m 2 /ha. O estudo demonstra maior semelhanca entre o cerrado sensu stricto de Buritis e o encontrado sobre solos rochosos no norte de Goias e sul de Tocantins, alem de detectar padroes floristicos que apontam a relacao da flora arborea entre diferentes areas no Brasil central.

Florística e Fitossociologia em Áreas de Cerradão e Mata Mesofítica na Estação Ecológica de Pirapitinga, MG

The objective of this study was to evaluate the floristic and phytosociological parameters of the species present in areas of mesophytic forest and dense woodland in the Pirapitinga Ecological Station, Minas Gerais state, Brazil. For the survey of floristic and phytosociological parameters, a total of 108 plots of 100 m2 were implanted, where all individuals with circumference at ground height (CGH) ≥ 16 cm were sampled in areas of dense woodland and mesophytic forest. The following parameters were calculated: frequency, density, dominance, values of importance and cover, Shannon and evenness indices, and floristic similarity by the Sorensen index. In both study areas, a total of 1,716 individuals of 67 species, 60 genera, and 35 families were sampled. The richest families were Vochysiaceae and Fabaceae. The dense woodland area presented the highest species richness (67) and the highest density, while the mesophytic forest area presented the greatest species development.

Florística e Fitossociologia em Áreas de Cerradão e Mata Mesofítica na Estação Ecológica de Pirapitinga, MG / Floristics and Phytosociology in Areas of Dense Woodland and Mesophytic Forest in the Pirapitinga Ecological Station, Minas Gerais State, Brazil

The objective of this study was to evaluate the floristic and phytosociological parameters of the species present in areas of mesophytic forest and dense woodland in the Pirapitinga Ecological Station, Minas Gerais state, Brazil. For the survey of floristic and phytosociological parameters, a total of 108 plots of 100 m2 were implanted, where all individuals with circumference at ground height (CGH) ≥ 16 cm were sampled in areas of dense woodland and mesophytic forest. The following parameters were calculated: frequency, density, dominance, values of importance and cover, Shannon and evenness indices, and floristic similarity by the Sorensen index. In both study areas, a total of 1,716 individuals of 67 species, 60 genera, and 35 families were sampled. The richest families were Vochysiaceae and Fabaceae. The dense woodland area presented the highest species richness (67) and the highest density, while the mesophytic forest area presented the greatest species development.

Estoque de Carbono e Nitrogênio e Abundância Natural de δ13C na Estação Ecológica de Pirapitinga, MG

The integrated assessment of physical attributes, carbon (StockC) and nitrogen (StockN) stock, and natural abundance of δ13C are effective in detecting landscape changes. Therefore, this study aimed to evaluate and compare the bulk density, StockC, StockN and natural abundance of δ13C in the soil profiles of different vegetation types of the Pirapitinga Ecological Station (EEP), to elucidate the changes in this area. For this, soil samples were collected and analyzed at depths up to one meter in different vegetation types of the EEP. The highest soil clay content and density of plant of forest vegetation promoted higher levels of StockC and StockN and lower bulk density values than the other grassland vegetation. The δ13C revealed that the areas of forest vegetation types were previously occupied mainly by plants of the C4 photosynthetic cycle, similar to grassland currently found in the EEP.

Carbono, Nitrogênio e Abundância Natural de δ13C do Solo em Coberturas Florestais

The aim of this study was to evaluate and compare the density (Ds) and content of carbon (C) and nitrogen (N), carbon (Cstock) and nitrogen stock (Nstock), and the natural abundance of δ13C in the soil profile of an area of Semideciduous Forest (SF) converted to eucalyptus monoculture (Corymbia citriodora) (ERN) in order to elucidate the changes in these environments. For this purpose, soil samples were collected at depths up to one meter in each study area. The conversion of FES to monocultures reduced Ds, N and EstC in the surface layer. However, there was an increase in EstC in the deeper soil layers. The δ13C isotopic signal of the vegetation that once occupied areas of C. citriodora plantation was similar to that currently found in the area of SF, and the time of conversion was at the depth of 0,40 m in the soil profile.

INFLUÊNCIA DA PEDOFORMA NA COMPOSIÇÃO DO BANCO DE SEMENTES EM FLORESTA SECUNDÁRIA NA REGIÃO DE MAR DE MORROS, PINHEIRAL - RJ

The composition and quality of the seed bank are some of the factors responsible for the structure and floristic composition of forest environments. The aim of this study was to evaluate the seed bank of a semideciduous forest patch, taking into account the influence of the landscape’s topographical features. Two adjacent landforms, of convex and concave shapes, were selected. They were divided into mini sites (MS) I, II, and III in the convex landform and IV, V and VI in the concave one. Ten sample points on each MS were randomly distributed with a surface area of 0.0625 m² and 3 cm deep. A total of 4,862 germinated seeds.m -1 was registered in 90 days, with the convex landform presenting the highest frequency of germinated seeds.m -1 . A total of 35 families and 88 species were identified in both landforms, of which 37% were of herbaceous habit, 24% arboreal, 18% shrubs, 12% lianas and 2% epiphytic. Regarding the landform’s shape, 44% of the species were found in both convex and concave ones, 31% were found exclusively on the convex landform and 25% exclusively on the concave one. Regarding floristic and phytosociological parameters, the convex landform accounted for a higher number of seeds, families, and species richness, while the concave landform accounted for higher diversity. Topography was a determinant factor for the floristic and phytosociological composition of the seed bank. The highest species richness was recorded in the convex landform and highest diversity in the concave landform, with Asteraceae, Melastomataceae and Urticaceae families presenting the highest importance indexes of value.