ABSTRACT Background: Tropical Dry Forests (TDFs) are repositories of biodiversity, ecosystem services and carbon that are threatened by fragmentation and climate change. Floristic and phytosociological studies are fundamental database for many studies of conservation and sustainability, but there is a knowledge gap concerning TDFs, especially in the Andes valleys. The aim of this study was to determine the phytosociological structure and composition of woody vegetation of seven TDFs in the Colombian Andes, and because the flora associated with this type of forest has a geographical distribution restricted to each locality where this biome exists, provide information on the main species, genera and families for conservation and restoration actions as well as for future meta-analyses. We sampled seven TDFs with 20 plots of 25 m × 4 m. Results: In the 1.88 hectares of samples, 8422 individuals were surveyed, distributed in 170 species, 120 genera and 50 botanical families. Of these species, 78.82% were identified at the species level, 17.05% at the genus level, and 4.11% at the family level. The most important families were Fabaceae and Myrtaceae. Nitrogen-fixing Fabaceae species were prominent amongst the important species, especially in low altitude and more stressing sites. Conclusion: The structure, composition and ecological importance of these forests must be considered for conservation and ecological restoration plans, in particular the habitat preference of species along the topographic gradient. Particularly noteworthy for conservation are the Myrtaceae species because promote connectivity and regeneration by providing resources for the fauna, a driver of dispersal, as well as nitrogen-fixing Fabaceae species, because promote the resilience and natural regeneration of TDFs in the Andes, a key feature of stability.

ABSTRACT The growth-survival trade-off hypothesis states that functional traits of stem, wood, leaves and fruits govern acquisitive and conservative strategies of plant species that grow/survive differently in forests. We aimed to determine whether heterogeneity during the colonization of a secondary Atlantic Forest fragment causes differences in colonization-related traits and determines taxonomic composition of subplots. A total of 5,078 subplots were censused with leaf and fruit traits and height measurements being determined for each tree of each species, and with averaged-abundance-weighted values calculated for each subplot. A dendrogram was generated from the taxonomic composition of subplots using Sorensen similarity and UPGMA clustering. A total of 74,335 trees of 178 species were recorded. Clustering revealed five main groups of subplots that were tested against each other and found to differ in terms of average leaf width, leaf-width/petiole-width, wood density, mean height, height mode, fruit width and fruit length. Greater leaf averages in subplots were associated with greater fruit averages, and with higher wood densities and greater heights among groups of subplots, revealing that heterogeneity during colonization directed the communities of the 50-ha plot. The averaged values of functional traits detected subplots associated with conditions favorable to colonization, thereby reinforcing the growth-survival trade-off hypothesis.

RESUMO Ainda que os inselbergs ao redor do mundo sejam ecossistemas icônicos, pouco se sabe sobre os mecanismos subjacentes que estruturam suas comunidades vegetais, especialmente nas manchas de vegetação sobre afloramentos rochosos. Espera-se que as restrições ambientais causem agrupamento filogenético quando os nichos ecológicos são conservados dentro das linhagens evolutivas. Nós testamos se as manchas de vegetação dos afloramentos rochosos do Monumento Natural Piedra La Tortuga, no norte da região amazônica, apresentam indicadores filogenéticos de que a filtragem ambiental é o principal direcionador da estruturação da comunidade. Classificamos todas as manchas de acordo com seu tamanho como muito pequenas (<1 m2), pequenas (1-4 m2), médias (4-8 m2) e grandes (8-15 m2). Selecionamos aleatoriamente 10 manchas em cada classe de tamanho, totalizando 40 manchas cobrindo 226 m2. Todos os indivíduos encontrados nas 40 manchas foram identificados ao nível de espécie. Correlacionamos as medidas da estrutura filogenética da comunidade com o tamanho das manchas e encontramos que as espécies das manchas são restritas aos clados das monocotiledôneas, fabídeas, malvídeas e lamiídeas. Concluímos que a vegetação neste afloramento rochoso é agrupada filogeneticamente. Além disso, encontramos que o turnover filogenético entre pares de manchas aumenta com o tamanho da mancha, o que é consistente com um cenário de alto estresse ambiental nas manchas menores. São necessárias mais pesquisas para identificar espécies facilitadoras, que são fundamentais para a conservação e restauração destes ecossistemas.

ABSTRACT Although inselbergs from around the world are iconic ecosystems, little is known on the underlying mechanisms of community assembly, especially in their characteristic patchy outcrop vegetation. Environmental constraints are expected to cause phylogenetic clustering when ecological niches are conserved within evolutionary lineages. We tested whether vegetation patches from rock outcrops of the Piedra La Tortuga Natural Monument, in the northern Amazon region, are phylogenetically clustered, indicating that environmental filtering is the dominant driver of community assemblage therein. We classified all patches according to their size as very small (< 1 m2), small (1-4 m2), medium-sized (4-8 m2), and large patches (8-15 m2). From each class, we randomly selected 10 patches, totalizing 40 patches covering 226 m2. All individuals found in the 40 isolated patches were identified to the species level. We also correlated measurements of phylogenetic community structure with patch size. We found that species from patches are restricted to the clades monocots, fabids, malvids, and lamiids. We conclude that vegetation in this rock outcrop is phylogenetically clustered. Furthermore, we found that phylogenetic turnover between pairs of patches increases with patch size, which is consistent with a scenario of higher environmental stress in smaller patches. Further research is necessary to identify nurse species in inselberg vegetation, which is pivotal for conservation and restoration of this particular ecosystem.

Resumen Aunque los inselbergs son afloramientos rocosos icónicos con un alto valor biogeográfico, poco se conoce sobre los mecanismos responsables de la estructuración de comunidades vegetales. El objetivo de esta investigación fue evaluar cómo el tamaño de los parches de vegetación influye en la relación especie-área y distribución de la abundancia de especies de una comunidad en un inselberg del Monumento Natural “Piedra La Tortuga”, región Guayana, Venezuela. Por este motivo, se establecieron tres preguntas de investigación: ¿Cuál es el efecto del tamaño de los parches sobre la riqueza de especies? ¿Qué tipo de modelo especie-área (SAR) presenta mejor ajuste en esos parches de vegetación? ¿Cómo es la distribución de las abundancias de las especies (SADs) es inducida por el tamaño de los parches? Se realizó un muestreo aleatorio estratificado en parches que oscilaron entre 0.34 y 14.8 m2, totalizando 40 unidades muestrales (226 m2). Todos los individuos encontrados en los 40 parches fueron identificados a nivel de especie. La composición florística en las diferentes muestras estuvo representada por 19 familias, 22 géneros y 24 especies, de las cuales 50 % son endémicas de inselbergs y dos están amenazadas de extinción. Se identificaron dos grupos de tamaños de parches (grandes 8-15 m2 y pequeños ≤ 7.9 m2) en relación a la abundancia y composición de especies, con diferencias significativas entre los grupos. Las curvas de acumulación de especies para cada grupo de tamaño de parche muestran una tendencia contrastante con marcadas diferencias en la riqueza observada entre los grupos de tamaños de parches. Las curvas de los modelos SADs tuvieron un ajuste significativo de la serie geométrica en las dos categorías de parches. El modelo SAR de la función potencia presentó los mejores ajustes especie-área, donde el aumento del área de los parches explicó un 82 % de la variación en el aumento del número de especies. Los resultados de este estudio demuestran por primera vez como el tamaño de los parches de vegetación de un inselberg tropical tiene una fuerte influencia sobre la riqueza, distribución de la abundancia y composición de especies. Así mismo, se determinó que el modelo geométrico SAD presentó el mejor ajuste en la comunidad en función del tamaño de los parches como un indicador de recursos, donde la abundancia de una especie puede ser equivalente a una proporción del espacio ocupado. También se presume que los cambios de tamaño de los parches, podría estar asociado con la disponibilidad de nutrientes y agua, como ha sido demostrado en otros ambientes de tierras secas. En algunos estudios se ha argumentado que la variación en la composición de especies entre los perfiles de vegetación de inselbergs tropicales está condicionada principalmente por la estructura del hábitat y el déficit hídrico. Sin embargo, no se había discutido cómo el tamaño de los parches de vegetación tiene un efecto en la riqueza. Los análisis SADs y SAR pueden proporcionar explicaciones complementarias sobre la estructuración de comunidades vegetales en inselbergs.

Abstract Although inselbergs are iconic rock outcrops with a high biogeographic value, little is known about drivers responsible for the plant community assembly. The aim of this research was to evaluate how the patch size distribution of vegetation influences the species-area relationship and species abundance distribution of a community in an inselberg of the “Piedra La Tortuga” Natural Monument of the Guayana region, Venezuela. In this context, three research questions were established: What is the effect of patch size on species richness? What species-area model (SAR) has the best fit in those vegetation patches? How is the distribution of species abundances (SADs) induced by the patch size distribution? A stratified random sampling was performed in patches ranging from 0.34 to 14.8 m2, totaling 40 sampling units (226 m2). All individuals found in the 40 patches were identified at species level. The floristic composition in the different samples was represented by 19 families, 22 genera and 24 species, of which 50 % are endemic to inselbergs and two, are threatened of extinction. Two groups of patch sizes were identified (large 8-15 m2 and small ≤ 7.9 m2) in relation to the abundance and composition of species. The species accumulation curves for each patch size group show a contrasting tendency with marked differences in the observed richness among patch size groups. The curves of the SADs models had a significant adjustment of the geometric series in the two categories of patches. The SAR model of the power function presented the best species-area adjustments, where the increase in patch area accounted for 82 % of the variation in the increase in the number of species. The results of this study demonstrate for the first time how vegetation patches of a tropical inselberg have a strong influence on richness, abundance distribution and species composition. Likewise, it was determined that the SAD geometric model presented the best fit in the community as a function of patch size as a resource indicator, where the abundance of a species can be equivalent to a proportion of the space occupied. It is also presumed that changes in patch sizes could be associated with nutrient and water availability, as has been demonstrated in other dryland environments. In some studies it has been argued that variation in species composition among vegetation profiles of tropical inselbergs is mainly conditioned by habitat structure and water deficit. However, it had not been discussed how the size of patches of vegetation has an effect on richness. SADs and SAR analyzes can provide complementary explanations on community assembly in inselbergs. Rev. Biol. Trop. 66(2): 937-951. Epub 2018 June 01.

ABSTRACT The computation of phylogenetic diversity and phylogenetic community structure demands an accurately calibrated, high-resolution phylogeny, which reflects current knowledge regarding diversification within the group of interest. Herein we present the angiosperm phylogeny R20160415.new, which is based on the topology proposed by the Angiosperm Phylogeny Group IV, a recently released compilation of angiosperm diversification. R20160415.new is calibratable by different sets of recently published estimates of mean node ages. Its application for the computation of phylogenetic diversity and/or phylogenetic community structure is straightforward and ensures the inclusion of up-to-date information in user specific applications, as long as users are familiar with the pitfalls of such hand-made supertrees.

ABSTRACT The Cerrado is the largest savanna of South America and its physiognomy varies from savanna to woodlands. There are two main types of woodlands in the Cerrado: dystrophic woodlands, dominated by N-fixing leguminous trees (LEG), and mesotrophic woodlands dominated by non-leguminous drought-tolerant trees (DRY), which are calcicoles and sensitive to Al3+. The working hypothesis is that LEG and DRY are functional antagonists in terms of the acidification/alkalization processes involving different forms of inorganic nitrogen and pH, Ca2+ and Al3+ in soil. Tree species basal area and soil properties were used to investigate the antagonism between LEG and DRY using generalized linear models. The results suggest that LEG and DRY are antagonists. The LEG were positively associated with Al3+, NO3- and NH4+ content and negatively related to increasing Ca2+ content, whereas the DRY were negatively associated with Al3+, NO3- and NH4+ and positively associated with increasing Ca2+ content. The upper soil layer in plots dominated by LEG species became more acidic and the upper soil layer in plots dominated by DRY species became more alkaline. The results suggest that LEG and DRY are functional antagonists and their preferences for NH4+ or NO3- might influence the way the Cerrado woodland changes.

RESUMO Segundo seus proprietários, a Floresta de Seu Nico (FSN), situada no Município de Viçosa, Minas Gerais, Brasil, nunca sofreu corte raso, porém é considerada floresta primária. No entanto, o fragmento florestal sofreu impactos por extração seletiva de madeira e produtos não madeireiros, além de fragmentação e isolamento. O objetivo desse estudo foi testar se a FSN, apesar de impactos, preservou características de florestas primárias, que são porcentagens elevadas de espécies não pioneiras (>80%), espécies dispersas por animais (>90%), espécies de sub-bosque (> 50%) e espécies endêmicas (~40%). Para isso, todas as árvores com diâmetro à altura do peito igual ou superior a 3,2 cm, dentro de uma parcela de 100 x 100 m, foram identificadas. Com 218 espécies de árvores encontradas dentro da parcela, a riqueza de espécies da FSN é elevada na região. As porcentagens de espécies não pioneiras (92 %), dispersas por animais (85%), de sub-bosque (55%) e endêmicas (39,2%) da FSN cumprem os critérios propostos para florestas primárias. Porém, conclui-se que a FSN manteve suas características como floresta primária, que destaca a sua importância para a conservação dos recursos bióticos da região, onde fragmentos semelhantes estão faltando ou, ainda, não foram descritos.

According to its owners, the Forest of Seu Nico (FSN) from the Viçosa municipality, Minas Gerais, Brazil, never has been logged and is therefore considered a primary forest. Nevertheless, the forest patch suffered impacts due to selective wood and non-timber extraction, fragmentation and isolation. Aim of this study was to test if the FSN, despite impacts, preserved characteristics of primary forests, which are elevated percentages of non-pioneer (>90%), animal-dispersed (>80 %), understory (>50%) and endemic species (~40%). For that, all trees with diameter at breast height equal or major than 3.2 cm within a plot of 100 x 100 m were identified. With 218 tree species found within this hectare, the FSN's species richness is outstanding for the region. The percentages of non-pioneer (92 %), animal-dispersed (85 %), understory (55 %) and endemic species (39.2 %) from the FSN fulfill the criteria proposed for primary forest. Therefore, we conclude that the FSN maintained its characteristics as a primary forest which highlights its importance for the conservation of biotic resources in the region, where similar fragments are lacking or not described yet.

Neste trabalho, objetivou-se determinar a diversidade florística e a estrutura fitossociológica da vegetação arbórea em gradiente topográfico de Floresta Estacional Semidecidual Submontana (Mata do Mumbaça), município de Dionísio-MG (19º48'S e 42º31'W). Todos os indivíduos lenhosos com diâmetro ao nível do peito (1,3m) ≥ 10cm foram medidos em 1,2 ha distribuídos em 120 parcelas 10 × 10m de modo a contemplar quatro unidades topográficas (Rampa Baixa, Baixa Encosta, Alta Encosta e Topo). Foram amostrados 2990 indivíduos com um total de 132 espécies, pertencentes a 92 gêneros, representados em 38 famílias. As faixas Alta Encosta e Topo apresentaram maior número de indivíduos, 870 e 822, respectivamente. As faixas que apresentaram maiores valores de área basal foram Rampa Baixa 24,60 m²/ha-1 e Topo 19,36 m²/ha-1. Somente Casearia arborea e Anadenanthera peregrina estiveram presentes entre as dez espécies mais importantes nas quatro faixas, porém algumas espécies ocuparam posições de destaque nas diferentes áreas estudadas como Anadenanthera peregrina e Xylopia aromatica no Topo, Myrcia fallax e Dalbergia nigra na Alta Encosta, Tapirira guianensis e Hortia arborea na Baixa Encosta e Apuleia leiocarpa e Siparuna guianensis na Rampa Baixa.

This study aimed to determine the floristic diversity and phytossociological structure of trees in a topographic gradient of lower montane semideciduous forest (Mata do mumbaça), municipality of Dionísio-MG (19 º 48'S and 42 º 31'W). All woody individuals with diameter at breast height (1.3m) ≥ 10cm were measured on 1.2 ha distributed in 120 plots 10 × 10m in order to include four topographic units (Low Ramp, Lower Slope Upper Slope and top). It was sampled 2990 individuals with a total of 132 species belonging to 92 genera, represented in 38 families. The Upper Slope and the Top showed higher numbers of individuals, 870 and 822, respectively. The tracks with higher levels of basal area were Lower Slope 24, 60 m²/ha-1 and Top 19, 36 m²/ha-1. Only Casearia arborea and Anadenanthera peregrina were present among the ten most important species in the four tracks, but some species occupie prominent positions in the different areas studied as A. peregrina and Xylopia aromatica on Top, Myrcia fallax and Dalbergia nigra in the Upper Slope, Tapirira guianensis and Hortia arborea in Lower Slope and Apuleia leiocarpa and Siparuna guianensis in Low Ramp.

Ecological theory predicts that, in mature ecosystems, species richness, the number of individuals and the biomass of individuals will remain in a relatively stable state of equilibrium. The aim of this study was to test that theory. In 2001 and 2010, we conducted censuses of all trees with a circumference at breast height > 10 cm in a one-hectare plot in a seasonal semideciduous old-growth forest in southeastern Brazil. We compared the two censuses in terms of species richness and diversity, computing growth, recruitment and mortality rates, as well as gains and losses of basal area. Between 2001 and 2010, species richness declined from 224 to 218 species and the basal area increased from 37.86 to 40.16 m² ha-1. Overall turnover (the mean difference between mortality and recruitment) was lower than would be expected for a seasonal semideciduous forest, indicating stability and slight successional advance. This interpretation is supported by the observation that pioneer species and canopy species both showed higher mortality than recruitment. However, uncommon species (< 10 individuals in the 2001 census) showed higher mortality than recruitment and became rarer, whereas most species that were abundant in 2001 became more abundant by 2010. These observations, as well as the decline in species richness, although statistically not significant, match the predictions of ecological theory for scenarios in which formerly contiguous ecosystems become fragmented and the remnants become isolated within the landscape. Nevertheless, further censuses are needed in order to test the idea that the observed patterns are not explained by natural oscillations but are consequences of environmental changes related to human activity.

O objetivo deste trabalho foi mapear e quantificar as áreas de preservação permanente (APPs) de acordo com a Resolução nº 303/02 do CONAMA para, então, com base no mapa de uso da terra e cobertura vegetal, identificar e quantificar os eventuais conflitos de uso da terra, com vistas a nortear o cumprimento da lei e promover o uso adequado dos recursos da sub-bacia hidrográfica do rio Camapuã/Brumado, MG. Utilizaram-se uma imagem digital do sensor ETM+/LANDSAT 7, bases cartográficas planialtimétricas do IBGE para a área de estudo, e os softwares Anudem 5.2, Erdas Imagine 9.2 e ArcGIS 9.3. As APPs ocuparam 63.095 ha, representando 57,0% da área total da sub-bacia (110.711,9 ha). Com relação às categorias de APPs, o terço superior da bacia, ao longo das linhas de cumeada, correspondeu a 52,6% dos 63.095 ha; as zonas de proteção às margens dos cursos d'água, a 31,4%; a proteção das nascentes, a 15,6%; e as encostas com declividade superior a 45° e o terço superior de morros totalizaram 0,4%. As áreas de terço superior da bacia, ao longo das linhas de cumeada, foram as mais desrespeitadas (55,9%), seguidas das margens de curso d'água (23,12%), proteção de nascentes (20,83%), encostas com declividade superior a 45° (0,3%) e terço superior de morros (0,1%). Foram identificados 21.939,3 ha de APPs sendo explorados por atividades agropecuárias, o que representa 34,8% do total de APPs. Entretanto, constatou-se que 30.734,3 ha dos 47.616,9 ha situados fora das áreas de APP, i.e., 64,5% das áreas legalmente passíveis de conversão de uso da terra, estavam cobertos por vegetação nativa. Encontraram-se sólidas evidências de que a falta de conhecimento a respeito da espacialização das APPs dentro da propriedade é a principal causa do descumprimento da lei. A delimitação e espacialização das APPs pelo geoprocessamento viabilizam a aplicação da legislação florestal, contribuindo notoriamente para minimizar os conflitos de uso da terra e evitar a degradação dos remanescentes florestais pela formação de corredores ecológicos naturais que mitiguem os efeitos deletérios da fragmentação de habitats.

The major bottleneck towards environmental compliance and law enforcement in Brazil is the lack of up-to-date maps accurately depicting the boundaries of protected areas as set by the Forest Code. A detailed study carried out over the Camapuã/Brumado watersheds, based on CONAMA's Act nº 303/2002, was meant to identify and quantify eventual land use legal conflicts. An ETM+/LANDSAT 7 digital image, topographic datasets and the softwares Anudem 5.2, Erdas Imagine 9.2 and ArcGIS 9.3 were used to create visual depictions of both permanent preservation areas (PPA) and land use/land cover. PPAs corresponded to 57,0% of the total area of the watersheds (110.711,9 ha), being 52,6% located on the upper third of hills along the watersheds' divides, 31,4% on riparian zones, 15,6% around springs and their drainage areas and 0,4% combining the areas situated on hillsides with slopes greater than 45° and on the upper third of hills. On one hand, farming activities were identified on 22.000 ha, representing 35% of the protected areas. On the other hand, 31.000 ha, accounting for 65% of the total area that could be legally converted to agricultural lands, were still preserved by native vegetation. These empirical evidences corroborate the hypothesis that the lack of suitable maps showing the limits of protected areas - a responsibility of Brazilian government - forces farmers to operate on the margin of the law, being the primary cause of illegal land use.

Este estudo teve como objetivos testar a hipótese de que a distribuição de espécies arbóreas num fragmento de Floresta Estacional Semidecidual Submontana, Zona de Amortecimento do Parque Estadual do Rio Doce, MG, é influenciada por variáveis geomorfológicas e edáficas e, dessa forma, fornecer subsídios para a recuperação de áreas degradadas em condições ambientais similares às da área de estudo. Foi realizado um levantamento detalhado de solos na área, com a abertura de perfis, sendo três em cada faixa (Rampa baixa, Baixa encosta côncava, Alta encosta côncava e Topo), totalizando 12 perfis. Nas coletas superficiais de solo foram colhidas quatro amostras compostas, na profundidade de 10-20 cm em cada faixa topográfica (Rampa baixa, Baixa encosta côncava, Alta encosta côncava e Topo), totalizando 16 amostras compostas. A partir dessas coletas foi realizada a caracterização química e granulométrica de cada amostra. Os solos foram classificados de acordo com o novo Sistema Brasileiro de Classificação de Solos. Os resultados da análise textural do solo na posição topográfica de Topo indicaram que a textura desse solo era muito argilosa. Nas posições topográficas Rampa baixa, Baixa encosta côncava e Alta encosta côncava, a textura variou de argilosa a argiloarenosa. O gradiente pedológico e topográfico é caracterizado por alterações nas propriedades físico-químicas do solo, sendo este amostrado (10-20 cm) na Rampa baixa mais arenosa, pouco mais fértil e menos ácida, em comparação com a do solo no Topo, mais argiloso, com teores baixos de macronutrientes e elevada acidez. A Baixa Encosta e Alta Encosta dos solos amostrados (a 10-20 cm), por sua vez, apresentaram condições edáficas intermediárias. Os teores de P eram limitantes em todos os solos. A distribuição das espécies ao longo do gradiente topográfico é associada com as variações da fertilidade química, acidez e textura do solo. Pera leandri, Astronium fraxinifolium, Pouteria torta, Machaerium brasiliense, Myrcia rufipes, Swartzia apetala e Lecythis lurida apresentaram suas distribuições correlacionadas com os teores elevados de alumínio e baixa fertilidade do solo, podendo ser indicadas para restauração de áreas degradadas em encostas e topos de morros em regiões com condições ambientais semelhantes às da área estudada. Pouteria venosa, Apuleia leiocarpa e Acacia polyphylla tiveram suas distribuições correlacionadas com solo menos ácido e mais fértil do ambiente mais plano de rampas, apresentando potencial para restauração de áreas similares.

The objective of this study was to test the hypothesis that the distribution of tree species in a fragment of submontane seasonal semideciduous forest, a buffer zone in the Parque Estadual do Rio Doce, Minas Gerais, is influenced by geomorphological and weather and soil variables, therefore it can represent a source of information for the restoration of degraded areas where environmental conditions are similar to those of the study area. A detailed soil survey was conducted in the area by sampling three soil profiles per slope segment, totaling 12 profiles. To sample the topsoil, four composite samples were collected from the 10-20 cm layers in each topographic range totaling 16 composite samples. In the low ramp and the lower and upper concave slopes, the texture ranged from clay to sandy-clay. The soil and topographic gradient was characterized by changes in the soil physical-chemical properties. The soil in the 10-20 cm sampled layer was sandier, slightly more fertile and less acid in the low ramp than the clayer soil, nutrient-poor and highly acid soil at the top. The soil conditions in the lower and upper slope of the sampled layers, in turn, were intermediate. The P levels were limiting in all soils. The species distribution along the topographic gradient was associated with variations in chemical fertility, acidity and soil texture. The distribution of Pera leandri, Astronium fraxinifolium, Pouteria torta, Machaerium brasiliense and Myrcia rufipes was correlated with high aluminum levels and to low soil fertility and these species may be indicated for restoration of degraded areas on hillsides and hilltops in regions where environmental conditions are similar. The distribution of Pouteria venosa, Apuleia leiocarpa and Acacia polyphylla was correlated with the less acid and more fertile soil in the environment of the low ramps, indicating the potential for the restoration of similar areas.

As sementes no solo desempenham o importante papel de promover a regeneração da vegetação e a conservação da biodiversidade local, mas, a despeito dessa importância, estão sujeitas a fatores bióticos e abióticos que podem inibir sua germinação, entre eles efeitos alelopáticos desencadeados pelas plantas que estão presentes no ambiente do solo. Neste trabalho foi testada a hipótese de que a germinação das sementes presentes no banco do solo sob vegetação de Floresta Estacional Semidecidual (FES) é inibida sob o dossel de espécies arbóreas exóticas. Foram coletadas 50 amostras simples de 0,25 x 0,25 x 0,05 m do solo em um fragmento de FES, que foram homogeneizadas, constituindo amostra composta. Desta, foram retiradas amostras que foram submetidas a quatro tratamentos: depositadas em casa de vegetação (SMN-CV); devolvidas ao fragmento de mata (SMN-MN); depositadas sob dossel homogêneo de Pinus elliottii (SMN-P); e alocadas sob plantio homogêneo de Eucalyptus sp. (SMN-E). Foram coletadas, também, amostras de solo sob dossel de P. elliotti (SP-CV) e de Eucalyptus sp. (SE-CV), que foram transferidas para casa de vegetação. A cada 15 dias, o número de plantas foi contado em cada amostra e as plantas obtidas, identificadas quando possível. Foram obtidas, ao todo, 515 plantas de 15 famílias botânicas, 21 gêneros e 13 morfoespécies. A análise de variância dos dados e a comparação das médias pelo teste de Tukey-Kramer a 0,01% evidenciaram que não existem diferenças estatisticamente significativas entre o número de plantas obtidas em cada local. Esses resultados indicam que a baixa densidade e diversidade de plantas frequentemente verificadas no subosque de P. elliotti e Eucalyptus sp. não estão diretamente relacionadas com efeitos supressores promovidos pela presença dessas espécies, suportando dados recentes da literatura que apontam os plantios florestais de espécies exóticas como possíveis áreas de conservação da biodiversidade, em oposição à alcunha de "desertos verdes" que lhe são atribuídos.

The seeds in the soil play an important role in promoting the plant regeneration and acts on the local biodiversity conservation, but despite their importance, they are subject to biotic and abiotic factors that may inhibit their germination, including allelopathic effects triggered by the plants that are present in the soil environment. In this study we tested the hypothesis that the germination of seeds of seedbeds from Semidecidual Seasonal Forest (SSF) is inhibited under the canopy of exotic trees. Fifty (50) single samples of soil were collected (0.25 x 0.25 x 0.05 m) in a fragment of SSF; the samples were homogenized and from that new samples were taken and submitted to four (4) treatments: 10 samples were deposited in the greenhouse (SMN-CV); other 10 were returned to the forest fragment understory (SMN-MN); 10 were deposited on the soil under homogeneous canopy of Pinus elliottii (SMN-P) and the last 10 samples were allocated under homogeneous plantation of Eucalyptus sp (SMN-E).We also collected samples of soil under the canopies of P. elliottii (SP-CV) and Eucalyptus sp.(SE-CV) that were transferred to a greenhouse. The number of seedlings was counted at intervals of 15 days in each seedbed sample and the plants obtained were identified when possible. We obtained 515 plants from 15 botanical families, 21 genera and 13 morphospecies. The analysis of variance and comparison of means by Tukey-Kramer 0.01% showed no statistical differences between the treatements. Outcomes indicate that the low density and diversity of plants in P. elliottii and Eucalyptus sp understory are not directly corelated to suppressive effects promoted by the presence of these species, supporting recent data from literature that stands out the forest plantations of exotic species as possible areas for biodiversity conservation, in opposition to the designation of "green deserts" that are assigned to them.

Foram realizados estudos fitossociológicos de duas áreas em campos rupestres quartzíticos e ferruginosos (sobre itabirito) de MG. Objetivou-se verificar se os litotipos e as geoformas influenciam a vegetação dessas comunidades. Os campos rupestres de ambas litologias foram estratificados pelas geoformas e fitofisionomias em: 1. Áreas inclinadas, com campos limpos 2. Platôs, com campos limpos e 3. Porções inferiores dos perfis, com campos sujos. Amostraram-se 60 parcelas (10x10m), 10 em cada habitat. Estimou-se a cobertura e calculou-se a frequência, dominância e valor de importância (VI) das espécies. Calculou-se a diversidade pelo índice de Shannon-Wiener (H') e equabilidade de Pielou (J') para cada habitat e a similaridade florística entre eles pelo índice de Jaccard e análise de agrupamentos. Inventariou-se 165 espécies nos campos quartzíticos e 160 nos ferruginosos. Nos campos rupestres declivosos e nos platôs ferruginosos Vellozia compacta foi a espécie de maior VI. Nos campos inclinados com afloramentos quartzíticos Lagenocarpus rigidus foi a espécie com maior VI, seguida por algumas fanerófitas. Echinolaena inflexa foi a espécie de maior importância nos platôs sobre quartzito, seguida por algumas fanerófitas e várias hemicriptófitas. Os campos sujos sobre itabirito foram dominados por E. erythropappus e V. compacta enquanto que os campos sujos sobre quartzito por Echinolaena inflexa, Eremanthus erythropappus e outras fanerófitas. Os campos sujos foram mais diversos que os campos limpos. Os campos rupestres ferruginosos apresentaram menor diversidade (H'=2,92) e equabilidade (J'=0,58) do que os quartzíticos (H'=3,36; J'=0,66). A análise de agrupamentos indicou a formação de grupos definidos pelas diferentes litologias e geomorfologias. Os resultados evidenciaram que a geologia e as geoformas influenciam a composição florística de campos rupestres.

The floristic composition and phytosociological structure of two areas with quartzitic and ferruginous (itabiritic) campos rupestres in the Quadrilátero Ferrífero region of Minas Gerais state were studied. The aim of this research was to determine if geology and geomorphology influence the vegetation of these communities. The campos rupestres in both lithologies were stratified in three kinds of geomorphologic/phytophysionomic habitats: 1. Slopes with grasslands; 2. Plateaus with grasslands and 3. Lower slopes with woody savannas. In each habitat, 10 plots (10x10m) were randomly defined, totaling 60 plots. Frequency, dominance and importance value (IV) parameters were calculated for each species. Shannon-Wiener (H') and Pielou (J') indexes were estimated for each habitat. Jaccard index and clustering analysis were used to assess the floristic similarity of the different habitats. There were 165 species in the quartzitic and 160 in the ferruginous grasslands. Vellozia compacta was the species with the highest IV in both ferruginous grasslands. Lagenocarpus rigidus was the species with the highest IV in quartzitic sloped areas, followed by several phanerophytes. Echinolaena inflexa was the species with the highest IV in quartzitic plateaus followed by several phanerophytes and many hemicryptophytic species. The woody savannas in ferruginous areas were dominated by E. erythropappus and V. compacta, while in quartzitic areas by Echinolaena inflexa, Eremanthus erythropappus and many phanerophytic species. Woody savannas were more diverse than grasslands. Ferruginous campos rupestres exhibited lower diversity (H'=2.92) and equitability (J'=0.58) than quartzitic ones (H'=3.36; J'=0.66). Cluster analysis produced groups corresponding to the lithological and geomorphological habitats. The results give evidence that geology and geomorphology influence the floristic composition of campos rupestres.

Este trabalho teve como objetivo obter grupos homogêneos de espécies e informações sobre sua densidade, dominância e volume, em termos de grupo ecológico e estrutura diamétrica de uma área de Floresta Estacional Semidecidual Submontana, em Dionísio, MG. O estudo foi realizado com dados de distribuição diamétrica, por espécies, provenientes do levantamento florístico e fitossociológico de 120 unidades amostrais de 10 m x 10 m cada da Mata do Mumbaça. As 120 parcelas eram contíguas, correspondiam a uma área amostral total de 12.000 m² e estavam distribuídas de modo a contemplar os estratos (Rampa Baixa, Baixa Encosta, Alta Encosta e Topo). Os estratos Rampa Baixa, Baixa Encosta e Alta Encosta encontravam-se em estágio médio de sucessão, visto que apresentavam estratificação incipiente em dois estratos (dossel e sub-bosque), ou seja, dossel variando entre 5 e 12 m de altura. Já o estrato Topo alcançou classificação de estágio médio/avançado de sucessão, pois obteve alturas totais iguais ou superiores a 12 m. A distribuição dos indivíduos arbóreos dos quatro estratos nas classes diamétricas apresentou um padrão típico de J-invertido, ou seja, alta concentração de indivíduos nas classes de menor diâmetro e redução acentuada no sentido das classes maiores. Com relação à dominância absoluta e volume total das espécies, o grupo ecológico que se destacou nos quatro estratos (Rampa Baixa, Baixa Encosta, Alta Encosta e Topo) foi o das secundárias iniciais, que se encontrava em estágio médio de sucessão secundária e em franco desenvolvimento para a fase madura

The objective of this study was to obtain homogeneous groups of species and information on their density, dominance and volume, in terms of ecological group and diameter structure of an area of Submontane Semideciduous forest (Mata do Mumbaça) in Dionísio, MG. This work was conducted with data of the diameter distribution per species from floristic and phytosociological (Mata do Mumbaça) survey of 120 plots with 10 x 10 m each one. The 120 plots were contiguous and corresponding to a total sample area of 12,000 m² distributed over the topographic units (Low Ramp, Lower Slope, Upper Slope and Hill Top). The topographic units Low Ramp, Lower Slope and Upper Slope were in the middle stage of succession as they presented incipient stratification into two strata (canopy and understory) i.e. canopy ranging from 5 to 12 m high. However, the stratum Hill Top was classified as intermediate/advanced succession because it had a total height equal to or greater than 12 m. The distribution of individual trees of the four strata on diameter classes showed a typical J-inverted pattern that is, high concentration of individuals in smaller diameter classes and a sharp reduction towards the larger classes. In relation to absolute dominance and total volume of species, the ecological group that stood out in the four strata (Low Ramp, Lower Slope, Upper Slope and Hill Top) was the initial secondary, which were in the intermediate stage of secondary, rapidly developing into the mature phase.

Procurou-se conhecer a flora de importância polinífera para Apis mellifera (L.) na região de Viçosa, MG, em período de entressafra de mel, entre agosto e dezembro de 2005. O experimento foi realizado em dois apiários distintos, cada um com cinco colmeias. As cargas retidas nos coletores de pólen instalados nas colmeias foram analisadas quanto à origem botânica. As plantas em floração no entorno dos apiários foram coletadas e identificadas. A maioria das plantas de importância polinífera para abelhas na região de Viçosa era nativa, localizada em jardins e com hábito arbóreo. Pela análise palinológica, verificou-se que espécies como Anadenanthera colubrina, Arecaceae sp., Baccharis dracunculifolia, B. melastomaefolia, Coffea spp., Emilia sagittata, Eugenia uniflora, Mikania cordifolia, M. hirsutissima, Myrcia fallax, Psidium guajava, Vernonia condensata, V. diffusa, V. lanuginosa e V. mariana são potenciais recursos poliníferos a serem utilizados no período de entressafra do mel. Os resultados indicaram a importância de plantas localizadas em áreas abertas para o forrageamento de pólen por A. mellifera e confirmaram o potencial polinífero da região estudada, durante o período de entressafra do mel.

The objective of this work was to study flora of polliniferous importance for Apis mellifera (L.) in the region of Viçosa-MG, during the period between honey harvests from August to December, 2005. The experiment was carried out in two different apiaries, each one with five beehives. The pellets retained in the pollen collectors in the beehives were analyzed with respect to their botanical origin. The flowering plants surrounding the apiaries were collected and identified. Most plants of polliniferous importance for the bees in the Viçosa region were native, located in gardens and with arboreal habitus. The palynological analysis showed that species such as Anadenanthera colubrina, Arecaceae sp., Baccharis dracunculifolia, B. melastomaefolia, Coffea spp.s are potential polliniferous resources to be used during the period between honey harvests. The results indicate the importance of plants located in open areas for pollen scavenging by A. mellifera, confirming the polliniferous potential of the studied area during the period between honey harvests.