Ivan Schiavini

An Ecological Comparison of Floristic Composition in Seasonal Semideciduous Forest in Southeast Brazil: Implications for Conservation

We examined floristic patterns of ten seasonal semideciduous forest sites in southeastern Brazil and conducted a central sampling of one hectare for each site, where we took samples and identified all individual living trees with DBH (diameter at breast height, 1.30 m) ≥4.8 cm. Arboreal flora totaled 242 species, 163 genera, and 58 families. Fabaceae (38 species) and Myrtaceae (20 species) were families with the largest number of species. Only Copaifera langsdorffii and Hymenaea courbaril occurred at all sites. Multivariate analysis (detrended correspondence analysis and cluster analysis) using two-way indicator species analysis (TWINSPAN) indicated the formation of a group containing seven fragments in which Siparuna guianensis was the indicator species. This analysis revealed that similarities between studied fragments were due mainly to the successional stage of the community.

Dinâmica da comunidade arbórea de mata de galeria da Estação Ecológica do Panga, Minas Gerais, Brasil

ABSTRACT – (Dynamics of a gallery forest tree community at Panga Ecological Station, Minas Gerais, Brazil). A study of treecommunity dynamics was carried out in two areas of gallery forest at the Panga Ecological Station, Uberlândia, MG. We analyzedchanges in the tree stratum over a 13-year period (1989-2002). Thirty plots (10×10 m) were set out in each area and all live in dividualswith dbh ≥ 4.8 cm were sampled. In area 1, a 1989 survey (T1) recorded 47 species and 501 individuals. The second survey (2002 = T2)recorded 50 species and 444 individuals. Loss of basal area (2.6 m 2 ) did not surpass growth of the survivors (2.38 m) plus incrementprovided by recruitment (0.57 m 2 ). In area 2, 54 species and 324 individuals were recorded at T1 and 52 species and 260 individuals atT2. Loss of basal area (1.44 m 2 ) surpassed survivors’s growth (1.04 m) plus the increment provided by recruitment (0.06 m 2 ). Area 1showed greater instability due to environmental changes, mainly in soil moisture, which led to the replacement of some species. Area 2,characterized at T1 as more stable, showed no important changes during the study period.

Estrutura e composição do estrato de regeneração em um fragmento florestal urbano: implicações para a dinâmica e a conservação da comunidade arbórea

This study was carried out in a semideciduous seasonal forest fragment with a long history of manmade disturbance, located in urban Uberlândia, Minas Gerais. The aim was to compare the composition and structure of the regeneration layer with that of the adult canopy layer in order to obtain information on environmental functioning and the dynamics of this plant formation. In 30 plots of 10×10 m, plants equal to or taller than one meter were surveyed, recording height and stem diameter at soil level. The presence of large trees of secondary species in the canopy layer, without corresponding abundance in the regeneration layer, suggests that disturbance affects the understory directly. The canopy of the seasonal forest at Parque do Sabia is composed of trees probably decades old; natural or manmade gap formation stimulates the establishment of pioneer species. In general, the important species of the regeneration layer suggest that the floristic composition of the community is changing in a process of succession characterized by the presence of many young individuals belonging to species of the early successional stages.

Comparison between canopy trees and arboreal lower strata of urban semideciduous seasonal forest in Araguari - MG

The present study intended to determine the phytosociological characteristics of the tree elements on the lower strata and the canopy of a semideciduous seasonal forest. The trees (> 15 cm circumference at breast height) were sampled in 40 plots of 10m x 20m. The individuals in the lower strata (> 1m up to 15 cm of circumference in the base of the stem) were sampled in plots of 10m x 10m. Licania apetala and Micrandra elata obtained the first and second places in the two strata. Among the species with the highest value of importance on the canopy, Alchornea glandulosa, Pimenta pseudocaryophyllus, Copaifera langsdorffii, Heisteria ovata and Didymopanax morototoni presented a ratio of less than one individual in the lower strata when compared to the canopy. However, there was a high floristic similarity between the lower strata and the canopy.

Mortality, recruitment and growth of the tree communities in three forest formations at the Panga Ecological Station over ten years (1997-2007)

ABSTRACT The area evaluated in this study was a continuous stretch comprising three vegetation formations: gallery forest, semi-deciduous seasonal forest and cerradao (woodland savanna). The aim of this study was to examine the tree community dynamics in a forest gradient—from gallery forest to cerradao —at Panga Ecological Station, in the city of Uberlandia, located in the state of Minas Gerais, Brazil. The study was based on data from a previous inventory of the continuous forest conducted in 211 permanent 10 × 10 m sample plots in eight parallel transect running perpendicular to Panga Creek. Trees with a diameter at breast height ≥ 4.77 cm were sampled in 1997, 2002 and 2007. With the exception of the cerradao , there was a net reduction in tree density over the studied period of ten years, because mortality rates were higher than the recruitment rates. The basal area in creased during the period of the study, especially at cerradao . The mean mortality rate in the studied area was 2.64%.yr

Estrutura fitossociológica e grupos ecológicos em fragmento de floresta estacional semidecidual, Uberaba, Minas Gerais, Brasil

RESUMO (Estrutura fitossociologica e grupos ecologicos em fragmento de floresta estacional semidecidual, Uberaba, Minas Gerais, Brasil) Estudos em florestas estacionais semideciduais (FES) sao necessarios para caracterizar a estrutura e verificar a formacao de padroes, possibilitando tambem comparacoes de composicao floristica entre fragmentos. Este estudo foi realizado em um fragmento de FES, em Uberaba, MG, na qual foram demarcadas 25 parcelas de 20 × 20 m, amostrando-se todos os individuos arboreos vivos com circunferencia do tronco a 1,30 m do solo > 15 cm. Foram analisados os parâmetros fitossociologicos usuais e, tambem, a similaridade floristica entre a area de estudo e outras areas de FES. Foram amostrados 805 individuos, representados por 90 especies, sendo Micrandra elata (Euphorbiaceae) a especie mais importante na comunidade, seguida de Galipea jasminiflora (Rutaceae). Especies pioneiras tiveram baixa representatividade na amostra. Alem disso, a presenca de individuos de grande porte, de especies pouco comuns, associada a area basal de 45,8 m 2 ha 1 , sao evidencias de se tratar de floresta madura, em bom estado de conservacao, representativa da condicao original. A analise de similaridade entre esta e outras areas florestais remanescentes demonstrou a formacao de quatro grupos distintos, associados a regioes geograficas, com indicios de que florestas em bom estado de conservacao sao mais semelhantes entre si. Palavras-chave: distribuicao espacial, floresta mesofila, similaridade floristica.

Plastic responses in tree architecture and specific leaf area of Xylopia aromatica (Annonaceae): adaptations to environments with different light intensities

The capacity of plants to occupy different environments is made possible by the plastic responses they present in heterogeneous environments. Light directly influences the plastic responses of plant functional traits, mainly involving leaf traits (specific leaf area and leaf dry matter content). Our objective was therefore to evaluate the phenotypic plasticity of Xylopia aromatica, a heliophilous species occurring in two physiognomies: cerrado sensu stricto (savanna—high light intensity environment) and Cerradão (woodland savanna—shaded environment). It is expected that trees growing in Cerradão will present adaptations that reduce self-shading and optimize their photosynthetic capacity. We sampled 40 trees (20 in each physiognomy) and collected seven parameters of tree architecture and specific leaf area (SLA) of these individuals. We found that in Cerradão, a closed and shaded physiognomy, X. aromatica showed significantly more cylindrical trunks, greater overall height, first branch height and SLA, and a lower crown length ratio. This differentiation can be defined as a plastic phenomenon, likely related to the higher efficiency of light interception and absorbance by trees and beyond to reduce self-shading in Cerradão. The plastic response of X. aromatica showed in this study is potentially a strong explanation for the adaptive success of cerrado plant species in different environments.

Dispersão de sementes de uruvalheira (Platypodium elegans vog.) (Fabaceae) em um cerradão, Uberlândia-MG

RESUMO – Estudou-se a dispersao de sementes de cinco arvores-matriz de Platypodium elegans Vog. (Fabaceae) em area de cerradao, na Estacao Ecologica do Panga (EEP). As amostragens foram feitas em parcelas de 0,25 m2, posicionadas em linhas partindo da base da matriz em direcao aos quatro pontos cardeais (Norte, Sul, Leste e Oeste), marcadas a cada metro. No laboratorio, os frutos foram abertos para analise da qualidade das sementes. Foram amostradas 1.131 sementes, das quais 18,4% estavam intactas e 81,6%, danificadas e provavelmente inviaveis para germinacao. A dispersao das sementes sofreu influencia da topografia do local das matrizes, das respostas fisiologicas e geneticas a pre-dispersao, bem como do possivel direcionamento favoravel do vento. Dessa forma, a atuacao conjunta desses fatores funcionaria como facilitadores relevantes na formacao do banco de sementes e moldaria a probabilidade de estabelecimento de novos individuos, tanto na area estudada quanto nas fisionomias adjacentes.. Palavras-chave: Cerradao, Platypodium elegans e Dispersao. SEEDS DISPERSAL OF URUVALHEIRA (Platypodium elegans VOG.) (Fabaceae) IN CERRADAO, UBERLANDIA, MG

Edaphic and structural differences between two seasonal forests in the Cerrado biome

Os estudos comparativos entre as florestas estacionais semideciduais (FS) e deciduais (FD) no bioma Cerrado sao raros. Para avaliar as diferencas quanto aos aspectos edaficos e estruturais desses dois tipos de florestas estacionais, foram escolhidos dois fragmentos que se localizam sobre neossolos litolicos nas encostas do vale do rio Araguari, oeste do estado de Minas Gerais. Os dois fragmentos se localizam muito proximos espacialmente e apresentam algumas condicoes ambientais semelhantes entre si. O componente arboreo (>15 cm CAP) foi amostrado em 60 parcelas 20 x 10 m, os teores de nutrientes e a textura dos solos, determinados em amostras superficiais (0-20 cm); e a umidade do solo, em amostras sazonais em tres profundidades (0-10 cm, 20-30 cm e 40-50 cm). Os resultados demonstraram que os solos das duas florestas diferiram significativamente quanto a capacidade de reter umidade no solo ao longo do ano e quanto a textura e teores dos elementos quimicos no solo. Cada floresta apresentou um conjunto proprio de especies edafoespecialistas, que influenciaram na composicao, diversidade e dominância em cada sitio. As duas fitofisionomias diferiram pouco quanto a estrutura do componente arboreo. Concluiu-se o estudo, ratificando que as duas florestas estacionais diferem entre si quanto a varios aspectos que se devem muito as condicoes edaficas de cada sitio. Confirmada essa tendencia em ampla escala, os dois tipos de florestas estacionais nao podem ser consideradas uma mesma fitofisionomia, o que normalmente ocorre, fato conclusivo que exige, portanto, elaboracao de planos de conservacao e manejo especificos. Palavras-chave: florestas tropicais estacionais, floresta estacional semidecidual, floresta estacional decidual, Cerrado, Minas Gerais.

Using short-term surveys and mark–recapture to estimate diversity and population size of orchid bees in forest formations of the Brazilian savanna

ABSTRACT Studies on the diversity and population dynamics of euglossine bees in forest formations of the Brazilian savanna can be notably informative considering that most species are forest-dependent. The current study aimed to estimate the diversity and population size of euglossine bees using short-term surveys and the mark–recapture method. We also compared short-term surveys with monthly surveys over a 1-year period (long-term surveys) to assess the species diversity. The study occurred in seven forest formations of the Brazilian savanna. We collected 14 species and marked 375 males but recaptured only 23 (6.1%). The population size of Euglossa bees ranged from 111.1 ± 34.4 to 1384.5 ± 384.6 males. The diversity indices achieved through the short-term surveys were similar to or higher than those obtained from long-term studies. The low recapture rate of euglossine males seems to be the result of their long-distance dispersal capacity. We also proposed that short-term surveys be viewed as a favourable alternative to long-term studies on diversity estimation and that euglossine bees can occur in small populations in some forest formations studied.