Exclusion experiments showed that atyid shrimps (Potimirim glabra) and baetid mayflies (Cloeodes ... more Exclusion experiments showed that atyid shrimps (Potimirim glabra) and baetid mayflies (Cloeodes sp., Americabaetis sp.) removed benthic material from hard substrate at different sites in the forested stream Rio Andorinha, Ilha Grande, Rio de Janeiro. Their effects were greater on organic material not associated with algae than on algae. Macrobrachium olfersi shrimp had a negative effect on the mayflies, causing
ABSTRACT The Caatinga biome in the semi-arid region of northeastern Brazil is extremely important... more ABSTRACT The Caatinga biome in the semi-arid region of northeastern Brazil is extremely important due to its biodiversity and endemism. This biome, which is under high anthropogenic influences, presents high levels of environmental degradation, land use being among the main causes of such degradation. The simulations of land cover and the vegetation dynamic under different climate scenarios are important features for prediction of environmental risks and determination of sustainable pathways for the planet in the future. Modeling of the vegetation can be performed by use of dynamic global vegetation models (DGVMs). The DGVMs simulate the surface processes (e.g. transfer of energy, water, CO2 and momentum); plant physiology (e.g. photosynthesis, stomatal conductance) phenology; gross and net primary productivity, respiration, plant species classified by functional traits; competition for light, water and nutrients, soil characteristics and processes (e.g. nutrients, heterotrophic respiration). Currently, most of the parameters used in DGVMs are static pre-defined values, and the lack of observational information to aid choosing the most adequate values for these parameters is particularly critical for the semi-arid regions in the world. Through historical meteorological data and measurements of carbon assimilation we aim to calibrate the maximum carboxylation velocity (Vcmax), for the native species Poincianella microphylla, abundant in the Caatinga region. The field data (collected at Lat: 90 2' S, Lon: 40019' W) displayed two contrasting meteorological conditions, with precipitations of 16 mm and 104 mm prior to the sampling campaigns (April 9-13, 2012 and February 4-8, 2013; respectively). Calibration (obtaining values of Vcmax more suitable for vegetation of Caatinga) has been performed through an algorithm of pattern recognition: Classification And Regression Tree (CART) and calculation of the vapor pressure deficit (VPD), which was used as attribute for discrimination of data. CART can be utilized for classification or regression, being used in the context of this work for non-linear regression. Our results show that CART algorithm correctly classified data according to the two contrasting periods (i.e. correctly distinguished assimilation data measured during drier or rainy periods), and suggest average Vcmax values of 14.2 μmol CO2 m-2 s-1 for the drier period and of 102.5 μmol CO2 m-2 s-1 for the rainy period. Comparing the values obtained in this work with values obtained through a traditional parameter optimization technique, it is possible to gauge pros and cons of such a combination of field measurements and machine learning technique.
Following an intense occupation process that was initiated in the 1960s, deforestation rates in t... more Following an intense occupation process that was initiated in the 1960s, deforestation rates in the Brazilian Amazon have decreased significantly since 2004, stabilizing around 6000km(2) yr(1) in the last 5 years. A convergence of conditions contributed to this, including the creation of protected areas, the use of effective monitoring systems, and credit restriction mechanisms. Nevertheless, other threats remain, including the rapidly expanding global markets for agricultural commodities, large-scale transportation and energy infrastructure projects, and weak institutions. We propose three updated qualitative and quantitative land use scenarios for the Brazilian Amazon, including a normative "Sustainability" scenario in which we envision major socioeconomic, institutional and environmental achievements in the region. We developed an innovative spatially-explicit modelling approach capable of representing alternative pathways of the clear-cut deforestation, secondary vegetation dynamics and the old growth forest degradation. We use the computational models to estimate net deforestation-driven carbon emissions for the different scenarios. The region would become a sink of carbon after 2020 in a scenario of residual deforestation (~1000 km(2) yr(-1) ) and a change in the current dynamics of the secondary vegetation - in a forest transition scenario. However, our results also show that the continuation of the current situation of relatively low deforestation rates and short life cycle of the secondary vegetation would maintain the region as a source of CO2 - even if a large portion of the deforested area is covered by secondary vegetation. In relation to the old growth forest degradation process, we estimated average gross emission corresponding to 47% of the clear-cut deforestation from 2007 to 2013 (using the DEGRAD system data), although the aggregate effects of the post-disturbance regeneration can partially offset these emissions. Both processes (secondary vegetation and forest degradation) need to be better understood as they potentially will play a decisive role in the future regional carbon balance. This article is protected by copyright. All rights reserved.
We will present in this study the nutrients transport in catchments of Brazil with different land... more We will present in this study the nutrients transport in catchments of Brazil with different land uses. We will emphasize the transport of dissolved carbon and nitrogen in 7 catchments of the São Paulo State, southeast region of Brazil. These are catchments ranging from 2,000 to 15,000 km2, where much of the main vegetation (Atlantic forest) was already replaced mainly
Abstract Carbon and oxygen isotope ratios have been measured to examine the impacts of a long-ter... more Abstract Carbon and oxygen isotope ratios have been measured to examine the impacts of a long-term drought treatment at the Seca Floresta in Santarem, Para, Brazil. We measured the carbon isotope ratio values of leaf organic matter and on the carbon dioxide effluxing from soil and litter components in droughted and non-droughted plots. We measured the oxygen isotope ratios of leaf water throughout the day. In addition, we quantified soil carbon dioxide efflux rates in order to partition this flux into its soil and litter components. The ...
Tropical forests harbor a significant portion of global biodiversity and are a critical component... more Tropical forests harbor a significant portion of global biodiversity and are a critical component of the climate system. Reducing deforestation and forest degradation contributes to global climate-change mitigation efforts, yet emissions and removals from forest dynamics are still poorly quantified. We reviewed the main challenges to estimate changes in carbon stocks and biodiversity due to degradation and recovery of tropical forests, focusing on three main areas: (1) the combination of field surveys and remote sensing; (2) evaluation of biodiversity and carbon values under a unified strategy; and (3) research efforts needed to understand and quantify forest degradation and recovery. The improvement of models and estimates of changes of forest carbon can foster process-oriented monitoring of forest dynamics, including different variables and using spatially explicit algorithms that account for regional and local differences, such as variation in climate, soil, nutrient content, top...
This paper discusses ways to reconcile the United Nations Millennium Development Goals with envir... more This paper discusses ways to reconcile the United Nations Millennium Development Goals with environmental sustainability at the national and international levels. The authors argue that development and better use of sustainability relevant knowledge is key, and that this requires capacity building globally, and especially in the less developed regions of the world. Also essential is stronger integration of high-quality knowledge creation and technology--and policy--development, including, importantly, the creation of centers of excellence in developing regions which effectively use and produce applications-directed high quality research and bring it to bear on decision making and practices related to environmental change and sustainable management of natural resources. The authors argue that Southern centers of excellence are a necessary first step for bottom-up societal transformation towards sustainability, and that such centers must help design innovative ways to assess and place...
In Brazil, Human Rights to Adequate Food was institutionalized in January 2010, incorporating ade... more In Brazil, Human Rights to Adequate Food was institutionalized in January 2010, incorporating adequate feed within the Citizens Social Rights as part of Brazilian Federal Constitution. Access to adequate food that guarantees and promotes such rights has been limited due to socioeconomic issues and environmental local and global changes. Expansion of cities in size and number, as well as population growth concentrated in urban areas might directly affect land availability for agriculture, reducing viable spaces near cities to produce fresh food in order to respond to the rise on demand for food by urban consumers. Vegetables are vital for a healthy human diet, and long market chains represent a damaging step between production and consumption, resulting in great losses due to high perishability, raising prices and difficulting access to food. Thus, the identification of near consumers areas suitable for vegetables´ production, can subsidize public policies and be part of adaptation m...
The main purpose of this study is to perform a nitrogen budget survey for the entire Brazilian Am... more The main purpose of this study is to perform a nitrogen budget survey for the entire Brazilian Amazon region. The main inputs of nitrogen to the region are biological nitrogen fixation occurring in tropical forests (7.7 Tg.yr(-1)), and biological nitrogen fixation in agricultural lands mainly due to the cultivation of a large area with soybean, which is an important nitrogen-fixing crop (1.68 Tg.yr(-1)). The input due to the use of N fertilizers (0.48 Tg.yr(-1)) is still incipient compared to the other two inputs mentioned above. The major output flux is the riverine flux, equal to 2.80 Tg.yr(-1) and export related to foodstuff, mainly the transport of soybean and beef to other parts of the country. The continuous population growth and high rate of urbanization may pose new threats to the nitrogen cycle of the region through the burning of fossil fuel and dumping of raw domestic sewage in rivers and streams of the region.
Exclusion experiments showed that atyid shrimps (Potimirim glabra) and baetid mayflies (Cloeodes ... more Exclusion experiments showed that atyid shrimps (Potimirim glabra) and baetid mayflies (Cloeodes sp., Americabaetis sp.) removed benthic material from hard substrate at different sites in the forested stream Rio Andorinha, Ilha Grande, Rio de Janeiro. Their effects were greater on organic material not associated with algae than on algae. Macrobrachium olfersi shrimp had a negative effect on the mayflies, causing
ABSTRACT The Caatinga biome in the semi-arid region of northeastern Brazil is extremely important... more ABSTRACT The Caatinga biome in the semi-arid region of northeastern Brazil is extremely important due to its biodiversity and endemism. This biome, which is under high anthropogenic influences, presents high levels of environmental degradation, land use being among the main causes of such degradation. The simulations of land cover and the vegetation dynamic under different climate scenarios are important features for prediction of environmental risks and determination of sustainable pathways for the planet in the future. Modeling of the vegetation can be performed by use of dynamic global vegetation models (DGVMs). The DGVMs simulate the surface processes (e.g. transfer of energy, water, CO2 and momentum); plant physiology (e.g. photosynthesis, stomatal conductance) phenology; gross and net primary productivity, respiration, plant species classified by functional traits; competition for light, water and nutrients, soil characteristics and processes (e.g. nutrients, heterotrophic respiration). Currently, most of the parameters used in DGVMs are static pre-defined values, and the lack of observational information to aid choosing the most adequate values for these parameters is particularly critical for the semi-arid regions in the world. Through historical meteorological data and measurements of carbon assimilation we aim to calibrate the maximum carboxylation velocity (Vcmax), for the native species Poincianella microphylla, abundant in the Caatinga region. The field data (collected at Lat: 90 2' S, Lon: 40019' W) displayed two contrasting meteorological conditions, with precipitations of 16 mm and 104 mm prior to the sampling campaigns (April 9-13, 2012 and February 4-8, 2013; respectively). Calibration (obtaining values of Vcmax more suitable for vegetation of Caatinga) has been performed through an algorithm of pattern recognition: Classification And Regression Tree (CART) and calculation of the vapor pressure deficit (VPD), which was used as attribute for discrimination of data. CART can be utilized for classification or regression, being used in the context of this work for non-linear regression. Our results show that CART algorithm correctly classified data according to the two contrasting periods (i.e. correctly distinguished assimilation data measured during drier or rainy periods), and suggest average Vcmax values of 14.2 μmol CO2 m-2 s-1 for the drier period and of 102.5 μmol CO2 m-2 s-1 for the rainy period. Comparing the values obtained in this work with values obtained through a traditional parameter optimization technique, it is possible to gauge pros and cons of such a combination of field measurements and machine learning technique.
Following an intense occupation process that was initiated in the 1960s, deforestation rates in t... more Following an intense occupation process that was initiated in the 1960s, deforestation rates in the Brazilian Amazon have decreased significantly since 2004, stabilizing around 6000km(2) yr(1) in the last 5 years. A convergence of conditions contributed to this, including the creation of protected areas, the use of effective monitoring systems, and credit restriction mechanisms. Nevertheless, other threats remain, including the rapidly expanding global markets for agricultural commodities, large-scale transportation and energy infrastructure projects, and weak institutions. We propose three updated qualitative and quantitative land use scenarios for the Brazilian Amazon, including a normative "Sustainability" scenario in which we envision major socioeconomic, institutional and environmental achievements in the region. We developed an innovative spatially-explicit modelling approach capable of representing alternative pathways of the clear-cut deforestation, secondary vegetation dynamics and the old growth forest degradation. We use the computational models to estimate net deforestation-driven carbon emissions for the different scenarios. The region would become a sink of carbon after 2020 in a scenario of residual deforestation (~1000 km(2) yr(-1) ) and a change in the current dynamics of the secondary vegetation - in a forest transition scenario. However, our results also show that the continuation of the current situation of relatively low deforestation rates and short life cycle of the secondary vegetation would maintain the region as a source of CO2 - even if a large portion of the deforested area is covered by secondary vegetation. In relation to the old growth forest degradation process, we estimated average gross emission corresponding to 47% of the clear-cut deforestation from 2007 to 2013 (using the DEGRAD system data), although the aggregate effects of the post-disturbance regeneration can partially offset these emissions. Both processes (secondary vegetation and forest degradation) need to be better understood as they potentially will play a decisive role in the future regional carbon balance. This article is protected by copyright. All rights reserved.
We will present in this study the nutrients transport in catchments of Brazil with different land... more We will present in this study the nutrients transport in catchments of Brazil with different land uses. We will emphasize the transport of dissolved carbon and nitrogen in 7 catchments of the São Paulo State, southeast region of Brazil. These are catchments ranging from 2,000 to 15,000 km2, where much of the main vegetation (Atlantic forest) was already replaced mainly
Abstract Carbon and oxygen isotope ratios have been measured to examine the impacts of a long-ter... more Abstract Carbon and oxygen isotope ratios have been measured to examine the impacts of a long-term drought treatment at the Seca Floresta in Santarem, Para, Brazil. We measured the carbon isotope ratio values of leaf organic matter and on the carbon dioxide effluxing from soil and litter components in droughted and non-droughted plots. We measured the oxygen isotope ratios of leaf water throughout the day. In addition, we quantified soil carbon dioxide efflux rates in order to partition this flux into its soil and litter components. The ...
Tropical forests harbor a significant portion of global biodiversity and are a critical component... more Tropical forests harbor a significant portion of global biodiversity and are a critical component of the climate system. Reducing deforestation and forest degradation contributes to global climate-change mitigation efforts, yet emissions and removals from forest dynamics are still poorly quantified. We reviewed the main challenges to estimate changes in carbon stocks and biodiversity due to degradation and recovery of tropical forests, focusing on three main areas: (1) the combination of field surveys and remote sensing; (2) evaluation of biodiversity and carbon values under a unified strategy; and (3) research efforts needed to understand and quantify forest degradation and recovery. The improvement of models and estimates of changes of forest carbon can foster process-oriented monitoring of forest dynamics, including different variables and using spatially explicit algorithms that account for regional and local differences, such as variation in climate, soil, nutrient content, top...
This paper discusses ways to reconcile the United Nations Millennium Development Goals with envir... more This paper discusses ways to reconcile the United Nations Millennium Development Goals with environmental sustainability at the national and international levels. The authors argue that development and better use of sustainability relevant knowledge is key, and that this requires capacity building globally, and especially in the less developed regions of the world. Also essential is stronger integration of high-quality knowledge creation and technology--and policy--development, including, importantly, the creation of centers of excellence in developing regions which effectively use and produce applications-directed high quality research and bring it to bear on decision making and practices related to environmental change and sustainable management of natural resources. The authors argue that Southern centers of excellence are a necessary first step for bottom-up societal transformation towards sustainability, and that such centers must help design innovative ways to assess and place...
In Brazil, Human Rights to Adequate Food was institutionalized in January 2010, incorporating ade... more In Brazil, Human Rights to Adequate Food was institutionalized in January 2010, incorporating adequate feed within the Citizens Social Rights as part of Brazilian Federal Constitution. Access to adequate food that guarantees and promotes such rights has been limited due to socioeconomic issues and environmental local and global changes. Expansion of cities in size and number, as well as population growth concentrated in urban areas might directly affect land availability for agriculture, reducing viable spaces near cities to produce fresh food in order to respond to the rise on demand for food by urban consumers. Vegetables are vital for a healthy human diet, and long market chains represent a damaging step between production and consumption, resulting in great losses due to high perishability, raising prices and difficulting access to food. Thus, the identification of near consumers areas suitable for vegetables´ production, can subsidize public policies and be part of adaptation m...
The main purpose of this study is to perform a nitrogen budget survey for the entire Brazilian Am... more The main purpose of this study is to perform a nitrogen budget survey for the entire Brazilian Amazon region. The main inputs of nitrogen to the region are biological nitrogen fixation occurring in tropical forests (7.7 Tg.yr(-1)), and biological nitrogen fixation in agricultural lands mainly due to the cultivation of a large area with soybean, which is an important nitrogen-fixing crop (1.68 Tg.yr(-1)). The input due to the use of N fertilizers (0.48 Tg.yr(-1)) is still incipient compared to the other two inputs mentioned above. The major output flux is the riverine flux, equal to 2.80 Tg.yr(-1) and export related to foodstuff, mainly the transport of soybean and beef to other parts of the country. The continuous population growth and high rate of urbanization may pose new threats to the nitrogen cycle of the region through the burning of fossil fuel and dumping of raw domestic sewage in rivers and streams of the region.
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Papers by Jean Ometto