Influence of edaphic variables on the floristic composition and structure of the tree-shrub vegetation in typical and rocky outcrop cerrado areas in Serra Negra, Goiás State, Brazil ABSTRACT -(Influence of edaphic variables on the floristic composition and structure of the tree-shrub vegetation in typical and rocky outcrop cerrado areas in Serra Negra, Goiás State, Brazil). The present study analyzed the influence of edaphic variables on the floristic compositions and structures of the arboreal and shrub vegetation of typical cerrado (TC) and rocky outcrop cerrado (RC) communities in the Serra Negra mountain range in Piranhas Municipality, Goiás State, Brazil. Ten 20 × 50 m plots were established in each community, and all individuals with minimum diameters ≥ 5 cm measured at 30 cm above soil level were sampled. Composite soil samples were collected at 0-20 cm depths in each plot for physical and chemical analyses. The proportions of above-ground rock cover work also estimated in each RC plot. A total of 2,009 individuals (83 species, 69 genera, and 34 families) were recorded. Qualea parviflora was the only species consistently among the 10 most structurally important taxa in both communities, and was considered a generalist species. The observed and estimated species richnesses were greater in RC than in TC, although plant basal areas and heights did not differ between them. There were positive correlations between rock cover × plant density and rock cover × basal areas. TWINSPAN and PCA analysis separated the TC and RC plots, and three RC habitat specialist species (Wunderlichia mirabilis, Norantea guianensis, and Tibouchina papyrus) were identified. Soil variables were found to have greater effects on the species compositions of the TC and RC sites than the geographic distances between sampling plots. According to CCA analysis, the exclusive (or more abundant species) of each community were correlated with soil variables, and these variables therefore determined the selection of some species and influenced the differentiation of the vegetation structures of the communities studied.

The ecology of seed dispersal is critical to understand the patterns of distribution and abundance of plant species. We investigated seed dispersal aspects associated with the high abundance of Buchenavia tomentosa in the Serra Azul State Park (PESA). We estimated fruit production and conducted fruit removal experiments. We carried out diurnal and nocturnal observations on frugivory as well as germination tests. Fruiting occurred in the dry season and totaled 1,365,015 ± 762,670 fruits.ha -1 . B. tomentosa fruits were utilized by eight animal species. The lowland tapir (Tapirus terrestris) was considered the main seed disperser. Leafcutter ants (Atta laevigata and Atta sexdens) participated in the seed cleaning and occasionally dispersed seeds. The beetle Amblycerus insuturatus, blue-and-yellow macaw (Ara ararauna) and red-and-green macaw (Ara chloropterus) were considered pre-dispersal seed predators. The seeds manually cleaned presented higher germination rate (100%) and speed index (4.2 seeds.d) than that of seeds with pulp. Germination of seeds found in tapirs'feces was 40%, while for the seeds without pulp it was 25%. The high abundance of B. tomentosa in the cerrado of PESA may be due to massive fruit production, low rates of seed predation, and efficient seed dispersal by tapirs, occurring before the rains which promote germination and recruitment of this species.Keywords: exclusion experiments, fruit production, frugivory, seed germination, tapir dung. Dispersão e predação de sementes de Buchenavia tomentosa Eichler (Combretaceae) em Cerrado sentido restrito, centro-oeste do Brasil ResumoA ecologia da dispersão de sementes é importante para entender a distribuição e abundância das espécies vegetais. Investigamos os fatores relacionados à elevada abundância de B. tomentosa no Parque Estadual da Serra Azul (PESA) avaliando aspectos da dispersão de sementes. Estimamos a produção de frutos e realizamos experimentos de remoção de frutos. Fizemos observações diurnas e noturnas sobre a frugivoria e testamos a germinação de sementes. A frutificação ocorreu na estação seca totalizando 1.365.015 ± 762.670 frutos.ha -1 . Oito espécies de animais utilizaram frutos de B. tomentosa. Anta (Tapirus terrestris) foi considerada o principal dispersor. Saúvas (Atta laevigata e Atta sexdens) participaram na limpeza das sementes e como dispersores ocasionais. O besouro Amblycerus insuturatus, arara-canindé (Ara ararauna) e arara-vermelha (Ara chloropterus) foram considerados predadores pré-dispersão. Sementes despolpadas manualmente tiveram maior percentual (100%) e velocidade de geminação (4,2 sementes.dia -1 ) que aquelas com polpa. Sementes encontradas nas fezes de antas apresentaram 40,0% de germinação e sementes sem polpa 25,0%. A massiva produção de frutos, baixa taxa de predação de sementes, além da eficiente dispersão por antas, antes da estação chuvosa, favorecem o recrutamento e são fatores que contribuem de forma decisiva para a elevada abundância de B. tomentosa observada no cerrado do PESA.Palavras-chave:...

ResumoO objetivo do presente estudo foi testar a hipótese de que remanescentes de florestas, mesmo em pequenas unidades de conservação e sujeitos a perturbações intermediárias, são resilientes. Para isso, as distribuições de diâmetros e alturas da comunidade e das espécies mais abundantes de um cerradão (14°42'02,3"S e 52°21'02,6"W) foram analisadas e comparadas em intervalos de dois a três anos em um período de oito anos. Em 2002Em , 2005Em , 2008 e 2010 foram medidas todas as árvores vivas com diâmetro ≥ 5 cm a 0,3 m do solo em 50 parcelas de 10 x 10 m. Mesmo com variações significativas na densidade, a distribuição de diâmetros e alturas da comunidade manteve o padrão de "J-reverso" e unimodal, respectivamente, indicando recrutamento contínuo e poucas mudanças na estrutura ao longo dos anos inventariados, corroborando a hipótese do presente estudo. Entre as espécies analisadas foram observados três padrões de distribuição diamétricas que provavelmente refletem diferentes estratégias de ocupação da floresta. Hirtella glandulosa foi a espécie mais apta a explorar os recursos do ambiente, apresentando as maiores abundâncias e indivíduos distribuídos em todas as classes de diâmetros. Palavras-chave: Distribuição de diâmetros; Fogo; Mato Grosso; Seca; Unidades de conservação Biotemas, 26 (3): 49-62, setembro de 2013 ISSNe 2175-7925 http://dx. Abstract Resilience of a cerradão subjected to intermediate disturbance in the Cerrado-Amazonia transition,Mato Grosso, Brazil. The present study examined the hypothesis that remnant forests in small protected areas may be resilient to intermediate disturbances. We analyzed the diameter and height distributions of the tree community in a typical cerradão (14°42'02.3"S and 52°21'02.6"W) and determined which species were most abundant, sampling at two-to three-year intervals over eight years. In 2002 and 2010, we measured all live trees with a diameter ≥ 5 cm at 0.3 m above ground in 50 plots of 10 x 10 m. Although significant variation was observed in the density of the trees and the distributions of their diameters and heights, the community maintained the "reverse-J" and unimodal patterns for these distributions, respectively. These results indicate continuous recruitment and little change in the structure of the community over the study period, supporting our hypothesis. Three different patterns of diametric distribution were observed among the analyzed species, likely reflecting different forest occupation strategies. Hirtella glandulosa was the speciesmost able to exploit its environment, as it possessed the greatest overall abundance and was represented by individuals in all diameter classes.

O objetivo deste estudo foi avaliar a distribuição das síndromes de polinização e dispersão entre borda e interior e entre os estratos verticais de um fragmento de cerrado sentido restrito, Ribeirão Cascalheira, Mato Grosso, Brasil. Foram estabelecidas cinco transecções de 100 x 4m, paralelas e distantes 100m entre si, onde foram medidos a altura e distância da borda de todos os indivíduos com diâmetro à altura do solo ≥ 5cm, considerando borda (primeiros 50m) e interior (últimos 50m) do fragmento. Os indivíduos foram classificados quanto à posição vertical que ocupam (estratos inferior, intermediário e superior) e quanto às síndromes de polinização e dispersão. Entre as 69 espécies amostradas, as síndromes de polinização e dispersão mais frequentes foram melitofilia e zoocoria, respectivamente. Ambas foram predominantes tanto na borda como no interior. Em geral, mais de 50% dos indivíduos localizados na borda e no interior e nos estratos inferior, médio e superior do fragmento tinham síndromes de polinização realizada por abelhas e dispersão por animais. A semelhança entre as síndromes de polinização e dispersão entre borda e interior se deve à elevada similaridade florística entre estes ambientes. A predominância das síndromes de polinização e dispersão realizadas por animais ressalta a importância de corredores ecológicos interligando e consequentemente mantendo a biodiversidade dos fragmentos.

The objective of this study was to verify the effect of biochar (granulated charcoal) added to an oxisol on the sugar beet seedlings production. The experiment was conducted in the seedlings nursery at the Mato Grosso State University, located at Nova Xavantina municipality, MT, Brazil, during the 2011 crop year. The experiment was carried out in a completely randomized design with five treatments and four repetitions. Different doses of biochar were applied to an oxisol in order to evaluate the seedlings growth and quality, studing the differences between doses of biochar through linear regression. The biochar addition to the oxisol did not promoted growth or quality increase on sugar beet seedlings. All the evaluated treatments presented poor seedlings development and quality, below the optimal level. The addition of low-chemical quality biochar in low fertility soils and with no fertilization is not recommended for sugar beet production during the short seedling production cycle.