Avaliação da produtividade em áreas de campo sujo com diferentes históricos de fogo

Fire is a common event in different ecosystems and can both be caused by humans or have natural sources.. In many of these ecosystems, natural fires are an important factor that determines the vegetation. The reduction of tree cover by fire for example, resulted in the evolution of several species-rich ecosystems, dominated by C4 grasses. However, the fire caused by human actions may have greater intensity and lead to negative responses of vegetation, since man changed the fire regime in many parts of the world, such as in the Cerrado. The passage of fire can benefit herbaceous and woody seedlings that cannot compete with the dominant grass layer. It removes the dead biomass and litter (major components of the fuel load), opening up spaces within the grass matrix that allow the establishment of other species. After some time without fire, an increase in shrub cover and decrease herbaceous layer can be observed. One of the major consequences of the absence of fire in savanna and grassland ecosystems is the accumulation of flammable dead biomass (mainly composed of graminoids), which will probably be the fuel load of the next burning thus, fires will be more intense and hotter. Moreover, very frequent burns lead to a reduction in the frequency and density of grasses. Therefore, this study aimed to assess the quantity and quality of biomass in areas with different fire history (fire exclusion for 2 and 7 years) in areas of campo sujo in central Cerrado. Plots (1x1m) were established in both areas and all aboveground biomass of each plot was cut at ground level and put in paper bags in the field. In the laboratory, the material was sorted into live and dead biomass. In addition, live biomass was separated into different functional groups (graminoids, forbs, Vellozia spp, palm and shrubs). The material was oven dried for two days at 80°C and subsequently weighed. In both areas, we found a dominance of graminoid and dead biomass. The area...

Seasonal fluctuation of soil carbon dioxide emission in differently managed pastures

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

Feedbacks between vegetation and disturbance processes promote long-term persistence of forest-grassland mosaics in south Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ecotoxicology of Nano-TiO2 An Evaluation of its Toxicity to Organisms of Aquatic Ecosystems

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Contamination of port zone sediments by metals from Large Marine Ecosystems of Brazil

Sediment contamination by metals poses risks to coastal ecosystems and is considered to be problematic to dredging operations. In Brazil, there are differences in sedimentology along the Large Marine Ecosystems in relation to the metal distributions. We aimed to assess the extent of Al, Fe, Hg, Cd, Cr, Cu, Ni, Pb and Zn contamination in sediments from port zones in northeast (Mucuripe and Pecem) and southeast (Santos) Brazil through geochemical analyses and sediment quality ratings. The metal concentrations found in these port zones were higher than those observed in the continental shelf or the background values in both regions. In the northeast, metals were associated with carbonate, while in Santos, they were associated with mud. Geochemical analyses showed enrichments in Hg, Cd, Cu, Ni and Zn, and a simple application of international sediment quality guidelines failed to predict their impacts, whereas the use of site-specific values that were derived by geochemical and ecotoxicological approaches seemed to be more appropriate in the management of the dredged sediments. (C) 2012 Elsevier Ltd. All rights reserved.

Environmental Fate of Neonicotinoids and Classification of Their Potential Risks to Hypogean, Epygean, and Surface Water Ecosystems in Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Distribuição de macroalgas lóticas de uma bacia de drenagem no Parque Nacional da Serra da Canastra, Minas Gerais, Brasil

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

Population genetic relationships between Casearia sylvestris (Salicaceae) varieties occurring sympatrically and allopatrically in different ecosystems in south-east Brazil

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

Meiotic chromosomes and nucleolar behavior in testicular cells of the grassland spittlebugs Deois flavopicta, Mahanarva fimbriolata and Notozulia entreriana (Hemiptera, Auchenorrhyncha)

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

Patterns of spatial distribution in macroalgal communities from tropical lotic ecosystems

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

Quality of the forage apparently consumed by beef calves in natural grassland under fertilization and oversown with cool season forage species

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

LONGITUDINAL DISTRIBUTION OF MACROALGAE IN 2 TROPICAL LOTIC ECOSYSTEMS FROM SOUTHEASTERN BRAZIL

Macroalgal species richness and diversity were analysed along a longitudinal profile in small and large scales during Spring, Fall and Winter, respectively in a small stream and a mid size river in the northwest region of São Paulo State, southeastern Brazil (20 degrees 23'-20 degrees 49'S, 49 degrees 26'-51 degrees 19'W). Longitudinal variation in species richness and diversity in small scale was strongly associated with incident light. Microhabitat distribution (from data taken by quadrat technique) revealed no significant correlations. Principal coordinates analysis (PCO) indicated no consistent groupings among sampling sites in distinct seasons (Spring, Fall and Winter). Longitudinal analysis in large scale revealed different patterns in the two seasons sampled (Spring and Winter), whereas species diversity presented a consistent tl end: high upstream, low in mid reaches and higher downstream. It was associated with type of substratum in Spring, rocky substrata presenting the highest values for species richness and diversity. Weak correlations were observed in Winter. Microhabitat distribution showed significant correlations between species abundance and the following variables: positive for rocky substrata and current velocity and negative for sandyclayish substratum and macrophyte-dominated substratum. PCO delineated only one consistent grouping formed by the two headwater sites. Small scale macroalgal distribution corroborated the longitudinal pattern predicted by the River Continuum Concept, whereas the large scale approach showed a distribution more associated with substratum type than to light availability. These results showed an opposite trend in relation to the expected distributional pattern. Longitudinal distribution in macroalgal community structure has yet to be better documented, particularly for tropical streams and no generalization is possible at this stage.

Comparative sediment quality assessment in different littoral ecosystems from Spain (Gulf of Cadiz) and Brazil (Santos and Sao Vicente estuarine system)

The goal of this work was to establish comparisons among environmental degradation in different areas from Southern Spain (Gulf of Cadiz) and Brazil (Santos and Sao Vicente estuary), by using principal component analyses (PCA) to integrate sediment toxicity (amphipods mortality) and chemical-physical data (Zn, Cd, Pb; Cu, Ni, Co, V, PCBs, PAHs concentrations, OC and fines contents). The results of PCA extraction of Spanish data showed that Bay of Cadiz, CA-1 did not present contamination or degradation; CA-2 exhibited contamination by PCBs, however it was not related to the amphipods mortality. Ria of Huelva was the most impacted site, showing contamination caused principally by hydrocarbons, in HV-1 and HV-2, but heavy metals were also important contaminants at HV-1, HV-2 and HV-3. Algeciras Bay was considered as not degraded in GR-3 and -4, but in GR-3' high contamination by PAHs was found. In the Brazilian area, the most degraded sediments were found in the stations situated at the inner parts of the estuary (SSV-2, SSV-3, and SSV-4), followed by SSV-6, which is close to the Submarine Sewage Outfall of Santos - SSOS. Sediments from SSV-1 and SSV-5 did not present chemical contamination, organic contamination or significant amphipod mortality. The results, of this investigation showed that both countries present environmental degradation related to PAHs: in Spain, at Ria of Huelva and Gudarranque river's estuary areas; and in Brasil, in the internal portion of the Santos and Sao Vicente estuary. The same situation is found for heavy metals, since all of the identified metals are related to toxicity in the studied areas, with few exceptions (V for both Brazil and Spain, and Cd and Co for Brazilian areas). The contamination by PCBs is more serious for Santos and Sao Vicente estuary than for the investigated areas in Gulf of Cadiz, where such compound did not relate to the toxicity. (c) 2006 Elsevier Ltd. All rights reserved.