Resumo A composição florística dos campos rupestres compreende um mosaico de espécies com adaptações distintas, exibindo alta diversidade e endemismo. Entretanto, as plantas dos campos rupestres possuem dependência às condições específicas do local e sua reprodução quase sempre é limitada, tornando difícil a regeneração natural após perturbações. O banco de sementes do solo representa um fator potencial para a regeneração deste ambiente. Objetivou-se avaliar o banco de sementes do solo de diferentes profundidades de uma área de campo rupestre, coletado em duas estações climáticas e submetido a duas condições de luminosidade. Foram coletadas amostras compostas de serapilheira e de solo (0-5 cm) em 13 parcelas de 100 m2, em uma área de campo rupestre na Serra do Cipó (Minas Gerais), nas estações seca e chuvosa. As amostras foram submetidas às condições de luminosidade pleno sol e sombreamento. No total, emergiram 185 plântulas pertencentes a 31 espécies e a nove famílias botânicas. As famílias com maior riqueza foram Cyperaceae, Poaceae e Asteraceae. Houve variação de riqueza, abundância e composição florística entre as profundidades do solo, mas não foi observada variação em relação à estacionalidade e às condições de luminosidade. As amostras de solo apresentaram valores superiores dos parâmetros avaliados em relação àquelas da serapilheira, mostrando que o banco de sementes é mais representativo no solo. Esses resultados demonstram que existe potencial de regeneração do campo rupestre por meio do banco de sementes do solo.

Abstract The floristic composition of the rupestrian grasslands comprises a mosaic of species with different adaptations exhibiting high diversity and endemism. However, the plant species from rupestrian grasslands are dependent on site-specific conditions and their reproduction is almost always limited, making natural regeneration after disturbances difficult. The soil seed bank represents a potential factor for the regeneration of this environment. The objective was to evaluate the soil seed bank of different depths of a rupestrian grassland area, collected in two climatic seasons and submitted to different light conditions. The samples composed of litter and soil (0-5 cm) were collected in 13 plots of 100 m2, in a rupestrian grassland area in Serra do Cipó (Minas Gerais state), in dry and rainy seasons. The samples were subjected to full sun and shading conditions. In total, 185 seedlings of 31 species and nine botanical families emerged. The richest families were Cyperaceae, Poaceae and Asteraceae. There was variation in richness, abundance and floristic composition among the soil strata, but no variation was observed in relation to seasonality and light conditions. The soil samples presented higher values of the evaluated parameters in relation to those ones of litter, showing that the seed bank is more representative in the soil stratum. These results demonstrate that there is potential for rupestrian grassland regenerations through the seed bank, especially the soil stratum.

Abstract Several plant-related factors can influence the diversity of gall-inducing species communities. In the present study we performed an inventory of gall-inducing arthropods and we tested if the plant species richness and the abundance of super-host plants (Copaifera oblongifolia) influenced positively in the diversity of gall-inducing arthropod species. The study was realized in an area of Neotropical savanna (cerrado sensu stricto) in the Environmental Protection Area (EPA) of Rio Pandeiros, Minas Gerais, Brazil. Host-plant species and gall-inducing arthropods were sampled in 18 10 × 10 m plots distributed in the vegetation. In total we found 40 arthropod gall morphotypes, distributed on 17 botanical families and 29 plant species. Cecidomyiidae (Diptera) induced the most arthropod galls (85%), and the plant family Fabaceae had the greatest richness of gall morphotypes (16). The plant species Copaifera oblongifolia and Andira humilis (Fabaceae) were the most important host species with five and three morphotypes, respectively. Galling species richness was not affected by none of explanatory variables (plant species richness and abundance of super-host plants). On the other hand, galling species per plant species was negatively affected by plant species richness and positively affected by abundance of super-host plants. This is the first study of arthropod-induced galls conducted in EPA of Rio Pandeiros, Brazil. Our results corroborate previous studies that highlight the importance of super-host plants for galling arthropod diversity on a local scale.

ABSTRACT The soil seed bank is an important natural regeneration strategy for plant communities and can determine floristic composition after disturbances. The aim of the present study was to evaluate the seed bank richness and abundance at different soil depths and under different light conditions in a dry forest. Litter and soil samples were collected at depths of 0-5 and 5-10 cm and submitted to two light conditions (light and shady). In total, 1,725 individuals from 85 species and 19 families emerged. Significant differences in richness between soil depths were observed, being greater at 0-5 cm, while abundance was similar. There were no variations in richness or abundance of germinated seeds between light conditions. Malvaceae and Verbenaceae families were the most representative in this study.

Resumo Este estudo analisou as variações florísticas, estruturais e suas relações com variáveis do solo em dois trechos de vegetação ripária em uma região ecotonal entre savana e zonas semi-áridas. Propomos a hipótese de que, apesar da proximidade entre as áreas amostradas, as condições do solo são distintas e levam a mudanças na estrutura e composição da vegetação, mas essas mudanças também são influenciadas pelo caráter ecotonal. Este estudo foi desenvolvido na APA do rio Pandeiros, Minas Gerais, onde alocamos 140 parcelas de 10 ×10 m (100 m2), com 10 m de distância entre parcelas, em duas áreas de vegetação ripária denominadas Larga e São Domingos (70 parcelas em cada área), onde realizamos o levantamento fitossociológico e coletamos amostras de solo. No total, 751 indivíduos arbóreos foram amostrados, distribuídos em 89 espécies e 35 famílias botânicas. As áreas diferiram fortemente na estrutura e composição das espécies, e apresentaram peculiaridades florísticas e influência da vegetação circundante. Apesar da baixa distância entre as áreas amostradas, estes são ambientes singulares influenciados por diferentes solos, pela composição mista da área ecotonal e os impactos antropogênicos a que estão expostas.

Abstract This study analyzed the floristic, structural variations and their relationships with soil variables in two stretches of riparian vegetation in an ecotonal region between savanna and semiarid zones. We following the hypothesis of despite the proximity between the sampled areas, soil conditions are distinct and lead to changes in structure and composition of the vegetation. This study was development at EPA of Pandeiros River, Minas Gerais, where we allocated 140 plots of 10 × 10 m (100 m2), with 10 m distance between plots, in two areas of riparian vegetation, named Larga and São Domingos (70 plots in each area), where we conducted the phytosociological survey and collected soil samples. In total, 751 arboreal individuals were sampled, distributed in 89 species and 35 botanical families. The areas differed strongly in structure and species composition, and showed floristic peculiarities and influence of surrounding vegetation. Despite of low distance between the sampled areas, these are singular environments influenced by different soils, by the mixed composition of the ecotonal area and the anthropogenic impacts to which they are exposed.