Above- and below-ground biomass and carbon dynamics in Brazilian Cerrado wet grasslands

Questions: Grasslands are usually neglected as potential carbon stocks, partially due to the lack of studies on biomass and carbon dynamics in tropical grasslands. What is the importance of Brazilian tropical wet grasslands as carbon sinks? Does fire frequency and season affect biomass and carbon allocation in Brazilian wet grasslands? Location: Wet grasslands, tropical savanna, Jalapão, Tocantins, northern Brazil. Methods: We determined biomass above- and below-ground, estimated carbon stocks in biennially burned plots (B2) and plots excluded from fire for 4 yr (B4). Moreover, we determined biomass in both rainy and dry seasons. Samples were 0.25 m × 0.25 m × 0.2 m (eight samples per treatment, applying a nested design, total of 48 samples). The biomass was classified in above-ground graminoids, forbs and dead matter, and below-ground roots and other below-ground organs. We used ANOVA to compare variables between treatments and seasons. Results: More than 40% of the total biomass and carbon stocks were located below-ground, mostly in roots. A high proportion of dead biomass (B4) was found in the above-ground material, probably due to low decomposition rates and consequent accumulation over the years. Although these grasslands do not experience water stress, we found significant evidence of resource re-allocation from below-ground organs to the above-ground biomass in the rainy season. Conclusions: We found more dead biomass in the rainy season, probably due to low decomposition rates, which can increase fire risk in these grasslands during the following dry season. These tropical wet grasslands stored high amounts of carbon (621 to 716 g C.m-2), mostly in the roots. Thus, policymakers should consider tropical grasslands as potential carbon stocks, since they are one of the most threatened and unprotected ecosystems in Brazil. © 2012 International Association for Vegetation Science.

Plantas de cobertura e qualidade química de latossolo Amarelo sob plantio direto no cerrado Maranhense

Aiming to evaluate the effect of cover plants over soil chemical attributes in the region of Balsas - Maranhão, samples of Oxisol under plant cover of millet [Pennisetum americanum (L.) Leeke], brachiaria (Brachiaria ruziziensis) and native Cerrado (mid-sized), were collected in three depths (0-0.10; 0.10-0.20 and 0.20-0.40 m). Plant cover of millet and brachiaria promoted an increase in soil pH and reductions in amounts of Al3+ and in saturation by Al3+, in relation to the area with native Cerrado. Major amounts of residue were verified on soil surface under native cerrado, due to greater input of plant residue and lower decomposition rate. Amounts of nutrients and levels of organic matter were higher in areas under millet and brachiaria cover, mainly in 0-0.10 e 0.10-0.20 m. depths. Brachiaria and millet cover plants were similar in relation to alterations promoted in chemical attributes of soil.

Florística e fitossociologia em áreas de campo sujo e cerrado sensu stricto na Estação Ecológica de Pirapitinga-MG

The objectives of this study were to characterize the floristic and to calculate the phytosociological parameters of species present in the areas of 'campo sujo' and 'cerrado' sensu stricto in the Ecological Station of Pirapitinga, Minas Gerais state (ESEC). For the floristic and phytosociologic survey, a total of 190 plots of 100 m2 each were allocated, where all the individuals with circumference at soil level (CSL) ≥ 16 cm in areas of 'campo sujo' and 'cerrado' sensu stricto were sampled. The parameters of frequency, density, dominance, and importance values and Shannon and Pielou indexes were calculated. The floristic similarity between areas was determinated by Sorensen index. In the study areas, a total of 3,224 individuals distributed in 81 species, 70 genera and 40 families were sampled. The richest families were Vochysiaceae and Fabaceae. The cerrado sensu stricto was the vegetal formation with the highest richness of species (81) and highest density (2.257 ind ha-1). Both areas have studied with high diversity and ecological dominance and have low diameter distribution in the form of inverted-J, indicating the predominance of young individuals.

Cloreto de potássio revestido em efeito residual no feijoeiro de inverno irrigado na região de cerrado

In order to maintain the nutrients available to plants have been studied controlled release fertilizers. In this context, the objective was to evaluate the residual effect of doses of potassium chloride, coated or not, applied in the corn crop, regarding the crop components and grains yield of irrigated winter common bean, cultivated in followed, in Cerrado region. The experiment was conducted in Selvíria - MS, Brazil, 51°22- west longitude and 20°22- south latitude, in a clayey Oxisol, in 2009 and 2010. A randomized block design with four repetitions was used, disposed in a factorial scheme 4 x 2, being: four K2O doses (0, 40, 80 and 120 kg ha-1) and two potassium sources (potassium chloride and coated potassium chloride by polymers) applied at sowing in the corn crop. The coated potassium chloride by polymers have the same residual effect as conventional KCl, because it provides results similar for the K and chlorophyll leaf contents, crop components and grains yield of winter common bean irrigated. The increment of potassium doses in the previous crop (corn) have residual effect, because it influenced positively the number of grains per plant in 2009 and increased linearly the chlorophyll leaf content and the grains yield of winter common bean irrigated in 2010, regardless of the source used for K.

Caracterização dos agregados em solos sob cultivo no Cerrado, MS

Impacts on the environment and soil biological activity result in changes in the processes of formation of biogenic and fisiogenic aggregates. Aiming to evaluate the influence on physical and biological genesis of aggregates of Cerrado soils and determine the main environmental factors that determine the characteristics of households in the area of production under integrated crop-livestock (ICL), was developed this study in Farm Cabeceira, Maracaju-MS, in areas of ICL. The areas evaluated were: Savana, pasture/maize, corn/cotton and cotton/soybeans being evaluated during the dry (May/2009) and rainy (March 2010) season. To identify the pathways of aggregation were used morphological patterns, and established three clusters: fisiogenic, biogenic and intermediates. The aggregates were analyzed for exchangeable cations, carbon and aggregate stability, soil was analyzed for the exchangeable cations, particle size fractionation of soil organic matter, oxidizable fractions of total organic carbon, particle size analysis and soil macrofauna. In all areas studied, in the dry season, the highest values were quantified aggregate intermediates, while in the rainy season, in general, no differences were observed aggregates formed by different routes in areas except cotton/soybeans. The aggregates showed positive correlation with biogenic carbon and were found in lesser amounts compared to fisiogenic and intermediates. The different types of aggregates formed, besides having different characteristics morphological also differ as to chemical characteristics.

Checklist of social (polistinae) and solitary (eumeninae) wasps from a fragment of Cerrado campo Sujo in the State of Mato Grosso do sul

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Applying machine learning based on multiscale classifiers to detect remote phenology patterns in Cerrado savanna trees

Plant phenology is one of the most reliable indicators of species responses to global climate change, motivating the development of new technologies for phenological monitoring. Digital cameras or near remote systems have been efficiently applied as multi-channel imaging sensors, where leaf color information is extracted from the RGB (Red, Green, and Blue) color channels, and the changes in green levels are used to infer leafing patterns of plant species. In this scenario, texture information is a great ally for image analysis that has been little used in phenology studies. We monitored leaf-changing patterns of Cerrado savanna vegetation by taking daily digital images. We extract RGB channels from the digital images and correlate them with phenological changes. Additionally, we benefit from the inclusion of textural metrics for quantifying spatial heterogeneity. Our first goals are: (1) to test if color change information is able to characterize the phenological pattern of a group of species; (2) to test if the temporal variation in image texture is useful to distinguish plant species; and (3) to test if individuals from the same species may be automatically identified using digital images. In this paper, we present a machine learning approach based on multiscale classifiers to detect phenological patterns in the digital images. Our results indicate that: (1) extreme hours (morning and afternoon) are the best for identifying plant species; (2) different plant species present a different behavior with respect to the color change information; and (3) texture variation along temporal images is promising information for capturing phenological patterns. Based on those results, we suggest that individuals from the same species and functional group might be identified using digital images, and introduce a new tool to help phenology experts in the identification of new individuals from the same species in the image and their location on the ground. © 2013 Elsevier B.V. All rights reserved.

Instantaneously measured traits may detect non-plastic ecophysiological performances in response to drought, explaining distributions of Styrax species in the Cerrado

We analyzed the differences between irrigated and non-irrigated plants of three congeneric Styrax species that present distinct distribution patterns in the physiognomies of the Cerrado vegetation in Brazil. Styrax ferrugineus showed a stomatal conductance (gs) unresponsive to soil water deficit in potted plants. This may explain the high gas exchange and photochemical efficiency found in this species, which is well adapted to the Cerrado sensu stricto (s. str.), a savanna-type vegetation. S. camporum, which is widely distributed in the Cerrado sensu lato (s. l.) areas, was the only species that exhibited increased intrinsic water use efficiency on the days of maximum water deficit. This result distinguishes S. camporum from S. pohlii, which is a forest species, since the gs of both species decreased during the days of maximum water stress. In contrast to other studies, we propose that instantaneously measured traits, such as leaf gas exchange rates and chlorophyll fluorescence, may be used to detect non-plastic performances in response to environmental stress, helping explain distinct geographical distributions of congeneric species in the Cerrado vegetation. © 2013 Springer-Verlag Berlin Heidelberg.

Fruit color and contrast in seasonal habitats - a case study from a cerrado savanna

Communication contributes to mediate the interactions between plants and the animals that disperse their genes. As yet, seasonal patterns in plant-animal communication are unknown, even though many habitats display pronounced seasonality e.g. when leaves senescence. We thus hypothesized that the contrast between fruit displays and their background vary throughout the year in a seasonal habitat. If this variation is adaptive, we predicted higher contrasts between fruits and foliage during the fruiting season in a cerrado-savanna vegetation, southeastern Brazil. Based on a six-year data base of fruit ripening and a one-year data set of fruit biomass, we used reflectance measurements and contrast analysis to show that fruits with distinct colors differed in the beginning of ripening and the peak of fruit biomass. Black, and particularly red fruits, that have a high contrast against the leaf background, were highly seasonal, peaking in the wet season. Multicolored and yellow fruits were less seasonal, not limited to one season, with a bimodal pattern for yellow ones, represented by two peaks, one in each season. We further supported the hypothesis that seasonal changes in fruit contrasts can be adaptive because fruits contrasted more strongly against their own foliage in the wet season, when most fruits are ripe. Hence, the seasonal variation in fruit colors observed in the cerrado-savanna may be, at least partly, explicable as an adaptation to ensure high conspicuousness to seed dispersers. © 2013 The Authors.

Pollination ecology of the Cerrado species Eschweilera nana (Lecythidaceae subfam. Lecythidoideae)

Eschweilera nana is pollinated by a guild of pollinators consisting of mostly bees. Effective pollinators are large bees able to force their way into the closed androecium to access nectar. The morphology of the flowers diminishes self pollination and promotes cross-pollination. Although many pollinators make diurnal visits to the flowers, fruit set was very low in comparison with the number of flowers produced. Breeding system tests yielded only two fruits, one produced by xenogamy and another one in the control test. The results of this study are consistent with studies of other Cerrado plants pollinated by guilds of insects and support the conclusion of other pollination studies of Lecythidaceae that fruit set is low in comparison with the high numbers of flowers produced. © 2013 The New York Botanical Garden.

Crescimento e avaliação nutricional de leguminosas arbóreas potenciais para ecossistemas agroflorestais num solo de cerrado

Pós-graduação em Agronomia (Agricultura) - FCA

Estudo da atividade antimicobacteriana de extratos vegetais do cerrado brasileiro

Pós-graduação em Biociências e Biotecnologia Aplicadas à Farmácia - FCFAR

Anurofauna em uma área de ecótono entre Cerrado e Floresta Estacional: diversidade, distribuição e a influência de características ambientais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Diversidade e distribuição dos lagartos de uma área de ecótono entre Cerrado e Mata Atlântica, no sudeste do Brasil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ácaros associados a plantas da região Core do Cerrado e sua influência na acarofauna em cultivos de soja (Glycine max (L.) Merril) (Fabaceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)