Publicações

Using a territorial and integrative approach based on ecological and socioeconomic factors, we envision innovative policies and initiatives aiming to reconcile urban economic development with rural conservation and restoration projects. The Paraíba Valley of São Paulo State represents an example of territory where the region’s urban development has affected land use and land cover changes, rural production systems, economy, and population dynamics with effects on environmental conservation. Forest restoration projects, rural tourism, urban to rural migration, and demands of urban consumers for more sustainable food production are becoming important linkages of the Valley’s coupled urban-rural system. In this study, we demonstrated how place-based policies and payment for ecosystem services may foster rural socioeconomic development allied with environmental conservation outcomes. The coupled ruralurban systems emerge as a strong concept to deal with the synergies and potential linkages among rural and urban areas, capable to promote more sustainable farming systems and improve ecosystem services.

In this study, we used the Standard Precipitation Index (SPI) to identify and to characterize the dry extreme events in the Amazon region. The results showed that the drought of 1998 was the most intense (SPI average equal to −1.69) in the period from 1979 to 2014. However, some papers have characterized the years 2005 and 2010 as the two largest droughts of the century. Thus, it was also carried out a comparative study of these droughts. The results showed that the drought 1998 was more intensive and extreme than the droughts of 2005 and 2010, although droughts of 2005 and 2010 lasted longer than 1998 due to oceanic and atmospheric conditions with influencing to cause greater social and economic impacts. Furthermore, it is suggested that the impact of the 2005 and 2010 droughts is a response from the dry occurred in 1993-1994 and 1997-1998.

This article reviews the current status, trends and challenges of land system science in Latin America. We highlight the advances in the conceptualization, analysis and monitoring of land systems. These advances shift from a focus on the relationships between forests and other land uses to include a greater diversity of land cover and land-use types and the processes and interactions that link them. We then provide a biome-level typology of social-ecological land systems (SELS) as an approach to help connect local-level realities to regional processes and we discuss how this approach can help to design more socially inclusive land systems. We also discuss the increased role of distant socio-economic and ecological interactions that connect these SELS to global processes. Combined, these insights support a research agenda for land system science in the region that can develop more accurate and integrative monitoring of land change and their social and ecological consequences, better understand different stakeholder perspectives within a context of livelihood diversification, and encourage institutional feedbacks to govern land systems influenced by distant drivers.

High-ozone concentrations currently represent the main air pollution problem in the city of São Paulo, Brazil. To elucidate the main volatile organic compounds (VOCs), which act as ozone precursors, samples from air quality monitoring stations were evaluated. Thirty-five samples were collected in AugustSeptember of 2006 and 43 in JulyAugust of 2008, when the consumption of ethanol was about 50 % of the total fuel used in the São Paulo Metropolitan Area. Samples were collected using electropolished stainless canisters. Chemical analyses were performed on pre-concentrated samples followed by gas chromatograph with flame ionization and mass spectrometry detection. The incremental reactivity scale was used to rank the ozone precursors using the Ozone Isopleth Package for Research (OZIPR) trajectory model coupled with chemical mechanism Statewide Air Pollution Research Center (SAPRC). Sixty-nine species of VOCs were quantified, and the ten main ozone precursors identified in 2008 were as follows: formaldehyde (42.8 %), acetaldehyde (13.9 %), ethene (12.2 %), propene (5.1 %), 1-methylcyclopentene (3.0 %), p-xylene (2.4 %), 1-butene (2.1 %), trans-2-pentene (1.9 %), 2-methyl 2-butene (1.7 %) and trans-2-butene (1.6 %). Volatile organic compound mass distribution showed that in 2008 alkanes represented 46 % of the total VOCs, alkenes 27 %, aromatics 14 %, alkadienes 1 % and aldehydes 12 %.

Large Amazonian rivers are characteristically subject to seasonal floods. We examine how inundation extent affects the partial pressure of carbon dioxide (pCO2) and CO2 outgassing in the Madeira River, a large tributary to the Amazon River. We show data from nine field campaigns performed between 2009 and 2011, complemented with data from one additional campaign in April 2014 that is representative of the largest flood on record. Both the pCO2 (range, 8359694 μatm) and CO2 outgassing (range, 64112,253 mg C m−2 d−1) had large seasonal variability (with peaks during high water), and fit exponential relationships with water level. CO2 outgassing per unit area in 2014 was 50% higher than the other highest rate in our dataset. Reconstruction of CO2 fluxes since 1968 indicates that extreme-flood years outgas 20% more CO2 per unit area than years without reported occurrence of extreme floods. Our findings indicate a positive feedback between climate change, extreme flooding, and CO2 outgassing from river water.

Analyzing Brazilian newspapers climate coverage leading up to 2010, this article shows that climate change was framed as an energy problem although energy is a small part of the countrys emissions compared to emissions from land use change and agriculture. Linked to well over half of national emissions, meat production is the single largest cause of national emissions. Yet discussions of meat as a problem in the context of climate change were marginal, at best. During the years 2007-2008, only 0.14% of climate change-mentioning articles – 0.02% of the total word count of climate change-mentioning articles – were dedicated to meat as a problem in the context of climate change. Counting also passages in articles not dedicated to the topic, the word count only rose to 0.13% of the total word flow of the articles. To the extent that the topic of meat as a problem appeared, it was underdeveloped and approached in ways that reduced attention, concern, and agency on the part of Brazilians to steer the country towards a new, more sustainable development path. This paper presents these findings and offers a preliminary political economic explanation for its existence.

The influence of social context in animal signals can lead to complex communicational patterns. In particular, the interaction between individuals can lead to intriguing collective dynamics, such as the temporal synchronization of signals. A fascinating example of such temporal synchronization involves the waving displays of fiddler crabs, in which males raise and lower their enlarged claws in species-specific rhythms. The adaptive significance of this phenomenon is still obscure, but possibly involves female preference for leading waving displays. However, waving displays are highly complex social signals that might be involved in a variety of forms of communication other than simply attracting females, but little is known about the influence of social context on wave synchronization. In this study we carried out field experiments to investigate the effect of two social factors, male density and female presence, on the level of waving synchronization in the fiddler crab Uca leptodactyla. Groups of males at varying densities were established in enclosures and recorded either in the presence or absence of a female. Our results indicate that the main factor driving synchronization is the presence of the female, with males not only changing the timing of their waving displays, but also altering their spatial distribution in the arenas. On the other hand, male density had a negligible effect on synchronization (despite significantly increasing waving rate), suggesting that malemale communication plays a minor role in the emergence of waving synchronization in this species.

Climate change and biodiversity loss have been reported as major disturbances in the biosphere which can trigger changes in the structure and functioning of natural ecosystems. Nonetheless, empirical studies demonstrating how both factors interact to affect shifts in aquatic ecosystems are still unexplored. Here, we experimentally test how changes in rainfall distribution and litter diversity affect the occurrence of the algae-dominated condition in tank bromeliad ecosystems. Tank bromeliads are miniature aquatic ecosystems shaped by the rainwater and allochthonous detritus accumulated in the bases of their leaves. Here, we demonstrated that changes in the rainfall distribution were able to reduce the chlorophyll-a concentration in the water of bromeliad tanks affecting significantly the occurrence of algaedominated conditions. On the other hand, litter diversity did not affect the algae dominance irrespective to the rainfall scenario. We suggest that rainfall changes may compromise important self-reinforcing mechanisms responsible for maintaining high levels of algae on tank bromeliads ecosystems. We summarized these results into a theoretical model which suggests that tank bromeliads may show two different regimes, determined by the bromeliad ability in taking up nutrients from the water and by the total amount of light entering the tank. We concluded that predicted climate changes might promote regime shifts in tropical aquatic ecosystems by shaping their structure and the relative importance of other regulating factors.

Tropical rainforest plays an important role in the global carbon cycle, accounting for a large part of global net primary productivity and contributing to CO2 sequestration. The objective of this work is to simulate potential changes in the rainforest biome in Central America subject to anthropogenic climate change under two emissions scenarios, RCP4.5 and RCP8.5. The use of a dynamic vegetation model and climate change scenarios is an approach to investigate, assess or anticipate how biomes respond to climate change. In this work, the Inland dynamic vegetation model was driven by the Eta regional climate model simulations. These simulations accept boundary conditions from HadGEM2-ES runs in the two emissions scenarios. The possible consequences of regional climate change on vegetation properties, such as biomass, net primary production and changes in forest extent and distribution, were investigated. The Inland model projections show reductions in tropical forest cover in both scenarios. The reduction of tropical forest cover is greater in RCP8.5. The Inland model projects biomass increases where tropical forest remains due to the CO2 fertilization effect. The future distribution of predominant vegetation shows that some areas of tropical rainforest in Central America are replaced by savannah and grassland in RCP4.5. Inland projections under both RCP4.5 and RCP8.5 show a net primary productivity reduction trend due to significant tropical forest reduction, temperature increase, precipitation reduction and dry spell increments, despite the biomass increases in some areas of Costa Rica and Panama. This study may provide guidance to adaptation studies of climate change impacts on the tropical rainforests in Central America.

We assessed the rainwater chemistry, the potential sources of its main inorganic components and bulk atmospheric deposition in a rural tropical semiarid region in the Brazilian Caatinga. Rainfall samples were collected during two wet seasons, one during an extremely dry year (2012) and one during a year with normal rainfall (2013). According to measurements of the main inorganic ions in the rainwater (H+, Na+, NH4 +, K+, Ca2+, Mg2+, Cl−, NO3 −, and SO4 2−), no differences were observed in the total ionic charge between the two investigated wet seasons. However, Ca2+, K+, NH4 + and NO3 − were significant higher in the wetter year (p < 0.05) which was attributed to anthropogenic activities, such as organic fertilizer applications. The total ionic contents of the rainwater suggested a dominant marine contribution, accounting for 76 % and 58 % of the rainwater in 2012 and 2013, respectively. The sum of the non-sea-salt fractions of Cl−, SO4 2−, Mg2+, Ca2+ and K+ were 19 % and 33 % in 2012 and 2013, and the nitrogenous compounds accounted for 2.8 % and 6.0 % of the total ionic contents in 2012 and 2013, respectively. The ionic ratios suggested that Mg2+ was probably the main neutralizing constituent of rainwater acidity, followed by Ca2+. We observed a low bulk atmospheric deposition of all major rainwater ions during both wet seasons. Regarding nitrogen deposition, we estimated slightly lower annual inputs than previous global estimates. Our findings contribute to the understanding of rainfall chemistry in northeastern Brazil by providing baseline information for a previously unstudied tropical semiarid ecosystem.