Uberlândia, Brazil
Uberlândia, Brazil

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Vargas B.C.,Federal University of Uberlandia | Araujo G.M.,Institute Biologia UFU | Schiavini I.,Institute Biologia UFU | Rosa P.O.,University of Brasilia | Hattori E.K.O.,Federal University of Minas Gerais
Bioscience Journal | Year: 2013

Climbers are important components of tropical forests and contribute to their species composition and richness. However only few studies have focused on this specific growth habit. The aim of this study was to determine the floristic composition of climbers in a riparian and a semideciduous forests in Uberlândia-MG, and compare these floras with other forest areas. The floristic survey was conducted monthly during 2006 and 2007 using random walks. The species collected were categorized according to the climbing habit, climbing strategy, dispersal syndrome and frequency of occurrence. Jaccard's similarity index with UPGMA was used to determine the floristic similarities. In both sites the sampling totaled 62 species, in 41 genera and 20 families. In semideciduous and riparian forests we found 39 and 33 species, respectively. The richest families in species were Malpighiaceae (9 spp.), Bignoniaceae (8 spp.) and Convolvulaceae (7 spp.) and the richest genera were Fridericia Mart. (5 spp.), Ipomoea L. (5 spp.) and Serjania Mill. (4 spp.). It was recorded a higher number of woody climbing than vines. The predominant strategies were twining-climbing mechanism and wind dispersal in both semideciduos and riparian forests. The floristic similarity between nine fragments analyzed was low, with species composition very heterogeneous, even among the closest areas, indicating a high _ diversity of climbers in these areas.

do Prado Junior J.A.,Federal University of Uberlandia | Lopes S.F.,Institute Biologia UFU | do Vale V.S.,Institute Biologia UFU | Dias Neto O.C.,Fundacao Carmelitana Mario Palmerio FUCAMP | Schiavini I.,Institute Biologia UFU
Bioscience Journal | Year: 2012

The present study aimed to determine the floristic, structural and ecological between physiognomies in a Cerrado remnant, Monte Carmelo, MG. From the phytossociological survey, we assessed the ecological patterns related to the species dispersion guilds and deciduousness. The floristic similarity between the physiognomies was parsed using quantitative and qualitative data (presence/absence) through the Jaccard similarity coefficient and Morisita-Horn indice. The urban remnant presented four vegetable physiognomies, classified in semideciduous seasonal forest, stricto sense cerrado, cerradão and gallery forest. We sampled 153 species, distributed in 49 families. The semideciduous forest covers the largest portion of the Park and has the greatest diversity of species. The gallery forest presented the less diversity, having as main representatives species adapted to conditions of hydromorphic soil. The predominance of zoochoric species in four physiognomies confirms the importance of biological agents on gene flow of these formations. The highest percentage of species anemochoric was found in the stricto sense cerrado and cerradão. The floristic similarity between the physiognomies present in urban remnant is low, demonstrating that small environmental variations reflect major floristic changes. Each physiognomies has its peculiarities, not only in relation to physical conditions, but also in relation to fundamental ecological processes, such as biological diversity and interaction with the fauna disperser, which may explain the great beta diversity found in the Cerrado biome.

The semideciduous forest in Sabia Park had suffered anthropogenic pressures for many years and since the elimination of disturbing factors, studies on floristic composition, structure and tree community dynamics has been carried out on site to see how the local plant populations are responding to these changes. The aim of this study was to describe the structure and dynamics of Amaioua guianensis population in an area of 0.2 ha, where all regenerating individuals of this species were measured for height and diameter and marked, after the rainy season of the years 2008 and 2009. It was found 151 individuals in 2008 and 175 in 2009, which totalized 32 recruits and eight deaths in 2009 and mortality and recruitment rates of 5.3% and 21.2%, respectively. Individuals were distributed in an aggregated manner. Population structure, represented by the measures of height and diameter, showed the shape of inverted "J", featuring a stable population on the distribution of individuals, but expanding due to the high rate of recruitment. The population seems to be regenerating successfully in the area and need long-term monitoring to detect a possible dominance of this species in the community.

This study aimed to determine the structure of trees and relates it to the soil conditions in a mesotrophic cerradão (CM) in Araguari and a dystrophic cerradão (CD) in Uberlândia, MG. In each area was sampled soil (0-20 cm depth) and tree species with diameter at breast height (CBH) ≥ 15 cm in 25 plots of 20 × 20 m. The percentage of canopy cover was verified in the dry and rainy seasons. The species richness (CM = 90 and CD = 83) represented (CM = 89% and CD = 88%) of species numbers estimated by Bootstrap method. Floristic similarity was low between the two cerradões (Jaccard = 0.28 and Morisita = 0.17), while the diversity index was different (in CM = 3.5 and CD = 3.2; Hutcheson t test = t = 7 28, p < 0.05). The basal area per plot did not differ between the two physiognomies (CD = 0.941 m2 and CM = 0, 947 m2, t = 0.0879, p <.005). The CD presented higher canopy cover in the dry and rainy seasons (F = 8.34, p < 0.006), higher concentrations of Al, Fe, sand and Al saturation (m%) than CM. CCA suggested that the distribution of the most abundant species in the CM is related to the values of K, Ca and clay and CD to Al. This suggests that the sensibility of species to Al may be an important factor in the selection of species with greater dominance in mesotrophic cerradão.

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