Andreza Viana Neri

Soil-vegetation relationships on a banded ironstone 'island', Carajás Plateau, Brazilian Eastern Amazonia.

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.

A woody community structure in a cerrado sensu stricto area of the municipality of Senador Modestino Gonçalves, north of Minas Gerais State, Brazil

The aim of this work was to study the phytossociological structure of a tree community in a cerrado fragment located in Senador Modestino Goncalves, MG. A total of 30 10x20m stands of tree individuals with stem circumferences at the soil level = 10cm were sampled, being found 91 species belonging to 38 families. The most important species were Qualea grandiflora, Eriotheca pubescens, Caryocar brasiliense, Byrsonima coccolobaefolia, Myrsine guianensis, Qualea parviflora, Dalbergia miscolobium, Stryphnodendron adstringens, Plathymenia reticulata and Lafoensia pacari. These species represented 49.32% of the importance value and 51.26% of the individuals. Besides standing out for its richness, the studied cerrado fragment also outstood out for its high tree density, biomass and diversity.

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 flood gradient and edaphic characteristics. The study was carried out at the Jacarenema Nautral Municipal Park, Vila Velha, Espirito Santo state, Brazil. We made four soil profiles varying in depth, and collected one sample from each horizon per profile. 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 floristic criteria of the different formations, and vegetation characteristics of each phytocenose were expressed by means of an illustrative profile. 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.

The Physical Environment of Rupestrian Grasslands (Campos Rupestres) in Brazil: Geological, Geomorphological and Pedological Characteristics, and Interplays

The Rupestrian Grassland is a vegetational complex with grassy to shrubby formations that occur throughout the high mountains of Brazil, usually formed by structurally resistant rocks, little affected by late tectonics, and strongly eroded and weathered under long term geological stability. RGC is closely associated with high altitude landsurfaces, in which several factors have a determinant role: (1) extreme oligotrophy, and acid, nutrient-depleted parent materials; (2) resistance to weathering and erosion (chemical and physical); (3) constant wind exposure; (4) intense fire regime. Variations of RG phytophysiognomies are basically due to soil depth (edaphic factor), drainage and landscape stability and evolution. Landforms (geomorphological attributes) affect the RGC at continental scales (high landsurfaces), regional scales (regional landforms, such as escarpments, valleys, slopes) and local scales (soil depth, stoniness, rockiness, drainage). The most common occurrence of RGC in Brazil is on Quartzite and metarenites, followed by canga and other Fe-rich substrates, igneous rocks and metamorphics, hence displaying a high diversity of substrates, with a major trait of extreme soil oligotrophy and acidity, and crucial variations in soil depth. The occurrence of well-documented areas of RG on Granitic and gneissic terrains imply that even richer rocks, submitted to long term weathering and erosion, can lead to similar soils on Highlands, where rock outcrops are also common (e.g. Caparao, Itatiaia, Brigadeiro, Serra dos Orgaos). RGC can occur immersed in different domains (Atlantic Forest, Caatinga, Cerrado), regardless of present day climates, since it represents an edaphic climax of long-term development. The widespread distribution of comparable RGC, from Amazonia (Carajas, Roraima, Pacaas Novos, Cachimbo) to the Central Plateau (Santa Barbara, Ricardo Franco, Pirineus) and Northeastern and Southeastern Brazil (Caparao, Espinhaco, Sincora, Jacobina, Itatiaia, Serra dos Orgaos, Brigadeiro, Carangola) raises the unresolved question of phylogenetic ancestry, age and similarities (floristic, structural) between those isolated islands of Rupestrian vegetation. These aspects are central to the evolution of Brazilian Biomes, representing key issues to resolve the late Quaternary Refuge Theory controversy, and test the validity of island biogeographical isolation theories.

Restinga forests of the Brazilian coast: richness and abundance of tree species on different soils

The aim of this study was to determine changes in composition, abundance and richness of species along a forest gradient with varying soils and flood regimes. The forests are located on the left bank of the lower Jucu River, in Jacarenema Natural Municipal Park, Espírito Santo. A survey of shrub/tree species was done in 80 plots, 5x25 m, equally distributed among the forests studied. We included in the sampling all individuals with >3.2 cm diameter at breast height (1.30 m). Soil samples were collected from the surface layer (0-10 cm) in each plot for chemical and physical analysis. The results indicate that a significant pedological gradient occurs, which is influenced by varying seasonal groundwater levels. Restinga forest formations showed significant differences in species richness, except for Non-flooded Forest and Non-flooded Forest Transition. The Canonical Correlation Analysis (CCA) showed that some species are distributed along the gradient under the combined influence of drainage, nutrient concentration and physical characteristics of the soil. Regarding the variables tested, flooding seems to be a more limiting factor for the establishment of plant species in Restinga forests than basic soil fertility attributes.

Composição florísitca de uma área de cerrado sensu stricto no município de Senador Modestino Gonçalves, Vale do Jequitinhonha (MG) e análise de similaridade florística de algumas áreas de cerrado em minas gerais

Studies on factors influencing species distribution are necessary because of the accelerated agricultural advancement over these species. Thus, this study aimed to assess Senador Modestino Goncalves floristic composition and possible cerrado floristic connections in Minas Gerais. Twenty-eight areas were assessed for floristic similarity, including Senador Modestino Goncalves. Sfrensen index was used in comparative analyses. Floristic analysis identified 91 species, 65 genera and 38 families. Greater richness was represented by Leguminosae (13), Malpighiaceae (11), Myrtaceae (7), Vochysiaceae (4), Sapindaceae (4), and Rubiaceae (4). A strong floristic similarity was found in cerrado vegetation, with six groups being formed with superior similarities for 0.5. However, the factors influencing this distribution could not be verified, but geographical proximity and altitude seem to have a strong influence on some of these groups.

Pedology and plant physiognomies in the cerrado, Brazil

This study was carried out in Paraopeba National Reserve. It aims to classify and evaluate the soil of the studied area and to verify the influence of soil attributes on vegetation by testing the following hypotheses: 1) under woodland physiognomies (Cerradão) the soil fertility is higher and the Al content lower; 2) open savanna occurs only in areas with high Al contents. For this purpose, representative soils in the Paraopeba National Reserve were mapped, identified, and samples from five profiles were analyzed. The environmental gradient was easily observed by principal components analyses, where the differences between the sites were highlighted. The Spearman correlation was used to verify the hypothesis. The correlation between vegetation (basal area, density, and richness) and soil (K, Ca2+, and Al3+) was statistically significant. The hypotheses were accepted, but hypothesis 1 only partially. Soil features seem to have an influence on the Cerrado phytophysiognomies and structure. Available phosphorous was an important factor for the maintenance of woodland Cerrado. Also, exchangeable Al3+ plays a major role in the establishment of different Cerrado physiognomies in Paraopeba National Reserve.

Plant diversity on granite/gneiss rock outcrop at Pedra do Pato, Serra do Brigadeiro State Park, Brazil

Campo de Altitude, one of the ecosystems associated with the Atlantic Forest, occurs mainly in high plateaus of Southeastern Brazil. The study area is in Serra do Brigadeiro State Park, Southeastern Brazil. We sampled six habitats (swamp field, Vellozia field, high mountain field, scrub slope, high altitude scrub, and cloud forest) that represent three physiognomies (grassland, scrub, and woodland). Overall, 180 species were recorded, belonging to 128 genera and 58 families. The richest families were Orchidaceae (20 species), Asteraceae (19), Melastomataceae (18), Rubiaceae (11), Myrtaceae (9) and Cyperaceae, Lauraceae, Solanaceae and Poaceae with five species each. The genera with highest number of species were: Baccharis , Miconia and Tibouchina with five species each; Solanum with four ; Paepalanthus, Myrcia, Myrciaria and Vellozia with three.

Structure and diversity of restingas along a flood gradient in southeastern Brazil

This study aimed to relate changes in structure and species diversity with edaphic variables (soil type and flooding regime) in a gradient of forest formations within the Brazilian restingas (coastal woodlands). The study was carried out in the Jacarenema Municipal Natural Park, in the city of Vila Velha, in the Espirito Santo State, Brazil. We evaluated the structure of shrub and tree components by sampling 80 plots of 5 × 25 m each, equally distributed among four forest types (well-drained, transitional, floodplain and flooded). We included all individuals with a ≥ 3.2 cm diameter at breast height. From each plot, soil samples (for chemical and physical analysis) were collected at a depth of 0-10 cm. We identified a significant fertility gradient (of soil nutrient availability) and a strong influence of groundwater on each forest type. We also found significant differences among the forest types in terms of individual basal area and height, as well as density. Diversity increased along the environmental gradient, from flooded to well-drained forest. We conclude that variations in structure and diversity among the four forest types were correlated with the flooding regime, as well as with chemical and physical characteristics of the soil.

Soil and altitude drive diversity and functioning of Brazilian Páramos (campo de altitude)

Aims the vegetation on Brazilian Páramos consists of assemblages that are driven mainly by the influence of strong environmental filtering. It is very important to understand the effect of environmental variation on taxonomic diversity and on functional diversity. considering the lack of information about the functional diversity in Brazilian Páramos, we analyzed for the first time the effects of altitude and edaphic attributes on functional traits, as well as on taxonomic and functional diversity. We also wanted to answer the questions: Which ecological strategies are favorable in high-altitude grassland? Does soil attributes determine distributions of traits in high-altitude grassland? considering the studied altitudinal gradient is altitude an important variable in the community assembly? Methods the study was conducted on three mountains: Mammoth (1850 m), Elephant (1790 m) and totem (1690 m) in Serra do Brigadeiro State Park, Minas Gerais State, Brazil. those mountains represent the ‘Serra das cabeças’, a smaller ridge that is surrounded by the Atlantic Forest, one of the 25 hotspot of biodiversity. the samples were taken using 100 plots of 1 m2 per mountain that were randomly distributed. All plants except mosses were sampled. the taxonomic diversity was evaluated using richness, Shannon diversity, effective number of species and Pielou evenness. For the functional diversity, we considered the functional richness, functional evenness and functional divergence. Generalized linear models (GLM/Poisson and quasi-Poisson) were used to evaluate the effect of abiotic variables (altitude, soil depth and soil chemical attributes) on biotic variables (number of species and individuals, life form, dispersal and fruit type) and ordinary least squares regression to evaluate the effect of abiotic variables on the functional and taxonomic diversity. Important Findings the soil variables presented a considerable edaphic gradient associated with altitude. the soil in Serra das cabeças plays an important role for the plant diversity: richness and diversity index were positively related with fertility. With regard to the life form, nanophanerophytes tended to increase with altitude and soil depth, while therophytes tended to decrease with altitude. the dispersal type was also associated with the abiotic variables: autochory decreases with altitude, while zoochory increases. Functional richness increases with fertility and the functional evenness with altitude. the studied gradient showed that altitude is working as a filter for functional traits and indices and is, together with soil attributes, an important determinant for the distribution of plants on Brazilian Páramos.