Glein Monteiro de Araújo

Comparação da vegetação arbórea de cerradão e de cerrado na Reserva do Panga, Uberlândia, Minas Gerais

The survey was carried out in the Panga Ecological Reserve, Uberlândia, Minas Gerais. A plot survey was used to analyze the floristic and phytosociology of arboreal species; with equal or more than 15cm of trunk girth, in a transect of 840m x 20m (1.68ha). The survey included plant communities of open cerrado and cerradao. Soil samples were collected, from 0 to 10cm depth, in 12 different plots, to define its chemical composition. The total survey included 3,137 individuals, in 107 species and 43 families. In the cerradao 25 plots (1.0ha) presented 93 species, with Qualea grandiflora, and Vochysia tucanorum showing the highest index of importance value (IVI). In 0.68ha of cerrado we found 76 species and 37 families, with Qualea grandiflora and Qualea parviflora presenting the higher IVI index. Fabaceae Vochysiaceae and Myrtaceae showed the largest number of species in the two plant communities

Composição florística de veredas no Município de Uberlândia, MG

Over a two-year period, four palm swamp communities near Uberlândia, MG, Brazil, were studied for their floristic composition. Transects were randomly established to cross the following zones: palm swamp border (dryish soils), middle area (intermediate soil moisture), and lower zone (with permanently satured soils). The transects were censused each month and voucher herbarium specimens were collected and identified by means of keys, comparisons with identified material at HUFU, IBGE and UB, and with the help of specialists for some families. Voucher specimens were deposited at HUFU. A total of 526 species, 250 genera and 89 families were collected. The five families with highest number of species were: Poaceae (64), Asteraceae (63), Cyperaceae (54), Melastomataceae (27) e Fabaceae (23). In the palm swamp border, 361 species were collected, 168 of which were exclusive to this zone. A total of 300 species were collected in the middle zone, of which 75 were exclusive to this area. The lower zone had the lowest species diversity, with 52 exclusive species from a total of 136 taxa. The great richness found in the palm swamp possibly is due to soil differences, especially those related to humidity.

Perfil nutricional de espécies lenhosas de duas florestas semidecíduas em Uberlândia, MG

O estudo teve como objetivo determinar a influencia da fertilidade sobre nutricao mineral e distribuicao das especies nativas em duas florestas semideciduas na Fazenda Experimental de Gloria (FEG) e Estacao Ecologica do Panga (EEP) em Uberlândia, MG. Foram amostradas de duas a quatro arvores, com circunferencia minima de 10 cm, a altura de 1,30 m do solo, de todas as especies encontradas em 50 parcelas contiguas de 10 m X 10 m, em cada floresta. Foram analisadas amostras de solo dos horizontes A1 e A3 de cada parcela nas duas florestas. O solo da EEP apresentou menor acidez, associada a maior disponibilidade de Ca e menor disponibilidade de Al, Fe, Zn e Cu. A disponibilidade Mn foi menor no horizonte A3 e maior no A1 na EEP. As concentracoes foliares de Ca e K foram maiores nas especies da EEP. As diferencas no teor de Ca refletiram a maior disponibilidade do nutriente no solo. Nao houve diferencas nas concentracoes foliares de P e Mg. O teor medio de N foi maior na floresta FEG do que na EEP, apenas em especies exclusivas. As concentracoes de Mn foram menores na EEP, refletindo a influencia do pH na absorcao deste nutriente. Assim, a ocorrencia de especies presentes exclusivamente na EEP pode estar associada a capacidade de absorver K e Mg de solos com altos teores de Ca.

Tree community dynamics in a semideciduous forest, in Uberlândia, Minas Gerais State, Brazil

This study describes the dynamics of a tree community based on two successive surveys carried out with a 14 years interval in order to analyze changes in the community structure during the period. The study was done in a semideciduous forest area using 50 plots of 10 m×10 m, where all trees with DBH > 3.18 cm were sampled. In 1990 there was registered a total of 95 species, 818 individuals and basal area of 14.43 m2, while in 2004, 95 species, 866 individuals and basal area of the 13.42 m2 . The floristic composition changed but the number of species remained same. The Shannons diversity index was 4.05 and the Pielous evenness 0.62 in 1990 and 3.72 and 0.57 in 2004, respectively. The mean annual mortality rate was 4.1% and the mean annual recruitment rate 4.5%. The half-life, the time duplication, stability and turnover were 16.92, 15.04, 1.86 e 15.98 years, respectively. The changes whitch occurred in the forest community shows that this fragment, althought maintaining general structure and species richness, is undergoings changes in diversity and equity which may be still the result of the fragmentation and isolation process.

Levantamento florístico de uma mata decídua em Uberlândia, Minas Gerais, Brasil

A floristic survey was carried out in a deciduous forest on a shallow basaltic soil, in Uberlândia, Minas Gerais. Visits were performed fortnightly from February/93 to June/95. The sampled material was lodged at the Herbarium of the Universidade Federal de Uberlândia (HUFU). A list is provided with 105 species of trees, shrubs, scandent shrubs, lianas and herbs, belonging to 88 genera and 43 botanic families. The most frequent species were: Anadenanthera colubrina, Bauhinia sp., Croton sp., Myracrodruon urundeuva and Sweetia fruticosa. Euphorbiaceae (10), Rubiaceae (8), Mimosaceae (6), Myrtaceae (6), Caesalpinaceae (5) e Fabaceae (5) were the families with the largest numbers of identified species.

A comunidade vegetal e as características abióticas de um campo de murundu em Uberlândia, MG

Murundus are small usually round mounds, that often present soil and vegetation different from the surrounding level area. All micro-elevations incountered in a 1.08ha murundu field had their length, width and height measured. The depth of the water table was measured and soil characteristics were obtained within and outside the murundus. All woody plants (lianas, trees, and shrubs) with a diameter of > 5 mm at ground level were identified. A total 434 elevations (31.4% of the total area) were encontered, of which 48 (24.3%) contained woody plants. The mound vegetation comprised 116 species belonging to 72 genera, and 42 families. The depth of the water table for those murunduns with woody plants varied between 99.2 and 206.8cm. The studied soil showed a low content of exchangeable bases, but only slight differences were observed between murundus and level soils. Matayba guianensis Aubl. and Erythroxylum suberosum A. St.-Hil. had the highest densities, while Copaifera langsdorffii Desf. and Blepharocalyx salicifolius (Kunth) O. Berg. showed the highest basal areas. The heigher diversity encountered here in comparison to other published reports may be due to cattle grazing and trampling as well as burning.

Structure and dynamics of a woody plant community of a tropical semi-deciduous seasonal forest in the "Estação Ecológica do Panga", municipality of Uberlândia, Minas Gerais, Brazil

Estudos de dinâmica de comunidades vegetais sao essenciais para o entendimento dos padroes demograficos das especies, uma vez que as mudancas nas taxas demograficas da comunidade podem afetar a composicao floristica e a estrutura futura das florestas. Portanto, o presente estudo teve por objetivo analisar as mudancas na composicao floristica e estrutura fitofisionomica da comunidade arborea de uma floresta tropical semi-decidua em Uberlândia no Brasil central, durante um periodo de 10 anos. O trabalho foi realizado em 50 parcelas de 10 m x 10 m, onde amostraram-se todas as arvores com circunferencia a altura do peito com minimo de 10 cm em 1989 e novamente em 2000. Em 1989 registrou-se um total de 93 especies e 1103 individuos, enquanto que em 2000, 92 especies e 1107 individuos. Em 10 anos houve a perda de oito especies e recrutamento de sete. A principal mudanca que ocorreu na composicao floristica nesse periodo foi a substituicao de especies de savana, que ocorriam nas clareiras, por aquelas de sub-bosque da comunidade florestal.

Distribuição vertical dos sistemas de polinização bióticos em áreas de cerrado sentido restrito no Triângulo Mineiro, MG, Brasil

Several factors can influence the distribution of floral resources and pollination systems in ecosystems, such as climate, altitude, geographic region, fragmentation of natural areas and differences in floristic composition along the vertical stratification. This study aimed to evaluate the distribution of the vertical stratification of biotic pollination systems in cerrado (sensu stricto) fragments in the Triângulo Mineiro. There was no significant difference (χ20.05,9=14.17; P = 0.12) in total plant species richness among fragments, nor in the species richness of each layer (trees, shrubs, herbs and lianas) and the shrub layer was the best represented. Likewise, there was no significant difference between fragments for the systems of pollination (χ20.05,21 =13.80; P = 0.8778). Pollination by bees was the most common, corresponding to 85% of species in each fragment. In relative terms, plants pollinated by bees were dominant in all strata, reaching 100% for the lianas in fragments 1, 3 and 4 and for the herbs in fragments 1 and 4. In this study, based on floristic composition and distribution of biotic pollination systems in the vertical stratification, we could define a vertical mosaic in the cerrado studied, which has implications for the sustainability of communities in the cerrado, as well as the horizontal mosaic of vegetation types.

Florística e zonação de espécies vegetais em veredas no Triângulo Mineiro, Brasil

(Floristica e zonacao de especies vegetais em veredas no Triângulo Mineiro, Brasil) A riqueza e a distribuicaodas especies vegetais, a profundidade do lencol freatico e a textura do solo nas zonas de borda, meio e fundoforam determinadas em cinco veredas em Uberlândia e Uberaba, Minas Gerais. A amostragem floristica foidesenvolvida, mensalmente de janeiro de 2002 a janeiro de 2003 em cada vereda. As coletas de solo e asmedidas do lencol freatico foram feitas na parte central de cada zona das veredas. Na amostragem floristicaforam encontradas 436 especies pertencentes a 59 familias e 206 generos. O numero de especies encontradonas seis veredas variou de 146 a 219. Na zona de borda, foram coletadas entre 26 e 87 especies enquanto nazona de meio, em geral, com maior riqueza especifica foram registradas entre 78 e 111 especies. A ordenacaofloristica mostrou variabilidade entre as veredas situadas em solo argiloso e arenoso e entre as zonas commaior e menor umidade do solo. A maior retencao de agua no solo argiloso pode ter interferido na variacao daflora entre as veredas em solo argiloso e arenoso.

Fire drives the reproductive responses of herbaceous plants in a Neotropical swamp

Palm swamps (veredas) are unique and diverse plant communities associated with the headwaters of streams in central Brazil, and they are frequently subjected to fires. We evaluated the effect of fire and the role of different fire-related cues on inducing reproduction by palm swamp vegetation. We compared the responses of species in burned plots, in plots in which the aboveground vegetation was clipped and then removed, and in unburned and unclipped control plots. Both the number of reproductive species and the total number of flowers/fruits produced by all species monthly were significantly greater in the burned than in the clipped and control plots, and greater in the clipped than in the control plots. For 34 of the 48 individual species analyzed the number of flowers/fruits produced per m2/month was greater in the burned than in the control plots, whereas the clipping treatment significantly increased the reproductive rate of only six species. This indicates that increased light availability was not the only factor inducing plant reproduction. Most likely, plant reproduction was also stimulated by the availability of soil nutrients whose concentrations increased significantly after burning. Although our results indicate that most plant species that occur in palm swamps are fire-recruiters, care must be taken in using fire as management tool, especially as the frequency of human-induced fires in palm swamps have increased dramatically in recent years.