Search

The conversion of Brazilian savanna into exotic pastures leads to the loss of dung beetles and a decrease in their contribution to ecological functions. We hypothesized that the dung beetle communities from exotic pastures would show greater significant differences between climatic zones, when contrasted to communities from Brazilian savanna in the same region, since dung beetle assemblages in pastures are more simplified. We assessed which variables (purpose of production, type of management, percentage the habitat per buffer, soil penetration resistance, pasture area and herd size) affect more the dung beetle community in exotic pastures. We carried out this study in 48 areas of native Brazilian savannas and exotic pastures distributed across four bioclimatic zones: BZ1, hot with three dry months; BZ2, hot with 4–5 dry months; BZ3, sub‐hot with 4–5 dry months and BZ4, meso‐thermal with 4–5 dry months of Minas Gerais State, Brazil. In each BZ, six areas of Brazilian savannas and six areas of exotic pasture were selected. In the Brazilian savanna areas, the species richness, abundance and biomass of dung beetles did not differ between the bioclimatic zones, unlike the exotic pastures. The composition of the dung beetle community was different between land use systems and between bioclimatic zones; the interaction between the two factors was also significant. Our results provide evidence that dung beetle communities active in exotic pastures are more susceptible to climatic environmental variations than communities from more complex and stable habitats, such as savannas. Finally, the best model suggested that all the six variables combined explained about 91% of the total variability in species composition observed between sampling sites. [ABSTRACT FROM AUTHOR]

Thematic maps of land cover and use can assist in the environmental monitoring of semiarid regions, mainly due to the advent of climate change, such as drought, and pressures from anthropic activities, such as the advance of urban areas. The use of geotechnologies is key for its effectiveness and low operating cost. The objective was to evaluate and understand the spatiotemporal dynamics of the loss and gain of land cover and use in a region of the Brazilian semiarid region, and identify annual trends from changing conditions over 36 years (1985 to 2020), using cloud remote sensing techniques in Google Earth Engine (GEE). Thematic maps of land cover and land use from MapBiomas Brazil were used, evaluated by Mann–Kendall trend analysis. The Normalized Difference Vegetation Index (NDVI) was also determined from the digital processing of about 800 orbital images (1985 to 2020) from the Landsat series of satellites. The trend analysis for land cover and use detected, over time, the loss of forest areas and water bodies, followed by the advance of exposed soil areas and urban infrastructure. The modification of native vegetation directly influences water availability, and agricultural activities increase the pressure on water resources, mainly in periods of severe drought. The NDVI detected that the period from 2013 to 2020 was most affected by climatic variability conditions, with extremely low average values. Thematic maps of land cover and use and biophysical indices are essential indicators to mitigate environmental impacts in the Brazilian semiarid region. [ABSTRACT FROM AUTHOR]

Climatic changes and land usage and cover (LULC) can significantly impact the availability of water resources in a region. On the other hand, water resources are intrinsically linked to economic production. Thus, managing water resources and their know-how on how they are affected by the climate and LULC are essential in regional development. The Global Climatic Model evaluated water resource management on its effects of climatic changes (2019–2099) based on four R epresentative Concentration Pathways (RCP 2.6, 4.5, 6.0, and 8.5) and the impact of changes in LULC in the Hydrographic Basin of the Cubatão River (HBCR), in Brazil. The fragilities of water resource management were observed. The scarcity of precipitation data made a direct impact on the estimated monthly average flow, as the estimated reduction was 45.4 % (RCP 2.6), 41.9 % (RCP 4.5), 43.2 % (RCP 6.0), and 41.7 % (RCP 8.5) by the end of the century. The forecast change in LULC reduces the impact on the decreased average monthly flow to 2.9 % by 2099 (RCP 2.6), 2.5 % (RCP 4.5), and 2.7 % (RCP 6.0 and 8.5). The actual evapotranspiration will be less than 2.4 % (RCP 2.6 and 6.0) and 2.3 % (RCP 4.5 and 8.5) with changes in the LULC in future scenarios. The HBCR already uses the entire status of authorized flow that will further aggravate as population growth continues. The results display faulty water resource maintenance of the basin that indeed will interfere in local economic development. • Climate change models estimate higher precipitation, but it is still insufficient. • Without the management of water resources, economic development is threatened. • The lack of instrument prevents the management of water resources. [ABSTRACT FROM AUTHOR]

Many aquatic species have restricted dispersal capabilities, making them the most vulnerable organisms to climate change and land use change patterns. These factors deplete Nymphaea species' suitable habitats, threatening their populations and survival. In addition, the species are poorly documented, which may indicate how scarce they are or will become. Members of Nymphaea are ecologically important as well as having cultural and economic value, making them of conservation interest. Therefore, using the maximum entropy (MaxEnt) approach, climatic variables, land use, and presence points were modeled for seven Nymphaea species in South America, using three general circulation models (CCSM4, HADGEM2-AO, and MIROC5) and in two representative concentration pathways (RCPs 4.5 and 8.5) and two scenarios (2050 and 2070). Our results indicated that mean diurnal range (bio2), precipitation of the wettest month (bio13), temperature seasonality (bio15), and land use (dom_lu) were the main influencing factors. For all species, suitable areas were concentrated east of Brazil, and they were variable in northern parts of the continent. Besides, inconsistent expansion and contraction of suitable habitats were noticed among the species. For example, N. amazonum, N. rudgeana, and N. lasiophylla future habitat expansions declined and habitat contraction increased, while for N. ampla and N. jamesoniana, both future habitat expansion and contraction increased, and for N. pulchella and N. rudgeana it varied in the RCPs. Moreover, the largest projected suitable habitats were projected outside protected areas, characterized by high human impacts, despite our analysis indicating no significant change between protected and unprotected areas in suitable habitat change. Finally, understanding how climate change and land use affect species distribution is critical to developing conservation measures for aquatic species. [ABSTRACT FROM AUTHOR]

Although global climate change is receiving considerable attention, the loss of biodiversity worldwide continues. In this study, dynamics of land use/land cover (LULC) change in the Paraguai/Jauquara Basin, Mato Grosso, Brazil, were investigated. Two analyses were performed using R software. The first was a comparative study of LULC among the LULC classes at the polygon scale, and the second was a spatio-temporal analysis of moving polygons restricted to the agricultural regions in terms of topology, size, distance, and direction of change. The data consisted of Landsat images captured in 1993, 1997, 2001, 2005, 2009, 2013, and 2016 and processed using ArcGIS software. The proposed analytical approach handled complex data structures and allowed for a deeper understanding of LULC change over time. The results showed that there was a statistically significant change from regions of natural vegetation to pastures, agricultural regions, and land for other uses, accompanied by a significant trend of expansion of agricultural regions, appearing to stabilize from 2005. Furthermore, different patterns of LULC change were found according to soil type and elevation. In particular, the purple latosol soil type presented the highest expansion indexes since 2001, and the elevated agricultural areas have been expanding and/or stabilizing since 1997. [ABSTRACT FROM AUTHOR]

The following research analyzed the interactions between climate change and land use in the Buritirana district, a farming region located at Jalapão gateway, Tocantins state, Brazil. This relatively small area gathers high-tech soybean production developed in recent years, cattle breeding, small family farming, and none associated producers. The study focused on two groups: on the one hand farmers of the agricultural settlements Sítio and Entre Rios and on the other large soybean producers. The database was obtained by the MapBioma project and the WorldClim collection. The images retrieved were processed to plot geographic illustrations and furthermore to elaborate and interpret linear regression. Such framework intended to provide more evidences about the future perspectives of agricultural production in tropical regions. The results revealed an annual increase of average temperature in the examined region, characterized by a strong expansion of soybean monoculture, between 2013 and 2018. However, based on statistical analysis, evidence of correlating soybean expansion to climate changes in the Buritirana region could not be confirmed. Nevertheless, spread of monoculture and reduction of native flora in the Jalapão region and surroundings should be considered with concern, especially for small rural familiar farmers and for wildlife as well, even after approval of the new Brazilian Forest Code in 2008. [ABSTRACT FROM AUTHOR]

Aim: To provide novel evidence on the average impact of climate and land use changes on habitat suitability for tropical plants and to test previous conclusions on the relative importance of these two drivers in shaping future availability of habitat for tropical plant species. Location: Brazil's Atlantic Forest domain. Time period: Plant occurrences recorded between 1960 and 2014. Baseline climate from 1960 to 2000 and land use from 2015. Projected scenarios of climate for 2041–2060 and land use for 2050. Major taxa studied: Angiosperms. Methods: We modelled the habitat suitability of 2,232 species of angiosperms from the Atlantic Forest domain, endemic to Brazil, and estimated how future climate and land use may affect species‐level habitat suitability under a moderate and a business‐as‐usual scenario for the year 2050. Results: Our results suggest that climate change alone will, surprisingly, have only a modest negative impact on the mean habitat suitability, decreasing it by 2% (median = −5 to −7%, variation associated with scenarios). Land use change alone had a more consistent negative impact on habitat suitability, causing mean and median reductions of 4 to 6%. When the effects of climate and land use are combined, the mean habitat suitability was reduced by 4% (median = −9 to −11%). Main conclusions: The combined impacts of climate and land use changes were substantial, although smaller than expected. Habitat suitability decreased for most species, but it increased substantially for some species, suggesting that the distribution of impacts across species is markedly right skewed. The impacts were typically detrimental to small‐ranged species and neutral or beneficial to widespread species. Land use change rather than climate change will likely cause more losses to the habitat of Atlantic Forest plant species within the next several decades. [ABSTRACT FROM AUTHOR]

Upland forest cover in the Amazon basin has been reduced by land use changes, e.g., the establishment of hydropower plants. Such plants cause permanent flooding and may produce periodic flooding in adjacent upland forests. We determined the short- and long-term effects of artificial flooding on the soil chemistry of upland forests adjacent to the Balbina Hydroelectric Reservoir, Amazonas State, Brazil. We randomized 20 sampling units in upland forests located on the banks of streams adjacent to the hydropower plant. Each sampling unit consisted of two paired forests: one artificial "flooded forest" near the stream and an unflooded "control forest." We performed soil chemical analyses to determine the pH and total organic C, N, Al3+, and nutrient levels (P, Ca, Mg, and K). In the short term, flooding caused soil acidification, C loss, and increased soil nutrient availability, but this effect did not occur in the long term. In the long term, soil acidity decreased, C loss occurred, and available N cumulatively decreased because of annual flooding after the impoundment of the reservoir. These cumulative N losses, associated with high C emissions, may alter the regional climate and contribute to global climate change. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ambiente e Água is the property of Revista Ambiente e Agua and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Future projections indicate an expansion for both food and energy demands, which can increase pressure on land use, while there is an urgent global need for climate change mitigation. Bioenergy is foreseen as key option to meet future energy demands and reduce greenhouse gas (GHG) emissions, however its sustainability depends on locations and regional characteristics. Simultaneously, agricultural production models that co-produce food, feed, and energy offer sustainability synergies and co-benefits, but site-specific sustainability assessments of their large-scale implementation are missing. This study presents a bottom-up approach to assess spatially explicit sustainability aspects of bioenergy-livestock integrated systems (BLI) in Brazil and shed light on their contribution to future energy demands, to climate change mitigation targets, and their impacts on selected ecosystem services, including bioenergy production, climate change mitigation, reduction of food competition, biodiversity conservation, and avoided deforestation. The proposed integration considers livestock intensification and use of biofuels by-products as animal feed supplement, taking advantage of synergies between these two value chains. The expansion of the BLI system in the Center-South region of Brazil produce up to 89 billion liters of ethanol, enough to meet future domestic ethanol demands from multiple shared socioeconomic pathways and generating surpluses for export. This production takes place on 16 million hectares of pastureland within the Sugarcane Agroecological Zoning, excluding the Amazon and Pantanal biomes, and biodiversity hotspots. BLI expansion mitigate up to 250 million tonnes of CO 2 eq and generate 15 billion dollars of profits. The best locations to maximize the selected ecosystem services are west of São Paulo, east of Mato Grosso do Sul, and the south-central region of the states of Goiás. This study may encourage the formulation of enhanced public policies for the integration of bioenergy and livestock value chains and guide a sustainable large-scale deployment of BLI systems. • Bioenergy and livestock integration (BLI): co-production of food, feed and energy. • BLI systems: 89 billion liters of ethanol and 250 million tonnes of CO 2 eq mitigated. • Enough ethanol to meet future Brazilian demands and surplus to be exported. • Biomass expansion only on pastureland inside Sugarcane Agroecological Zoning. • Without land displacement and deforestation of native vegetation. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Specialisation at national level hampers mitigation-adaptation integration. • Local actors prioritize climate adaptation but lack of influence hinders action. • Decentralisation affects cross-level power differentials in land and climate domains. • Dominant national level communities exclude localities from policy decisions. Abstract This article proposes an innovative theoretical framework that combines institutional and policy network approaches to study multi-level governance. The framework is used to derive a number of propositions on how cross-level power imbalances shape communication and collaboration across multiple levels of governance. The framework is then applied to examine the nature of cross-level interactions in climate change mitigation and adaptation policy processes in the land use sectors of Brazil and Indonesia. The paper identifies major barriers to cross-level communication and collaboration between national and sub-national levels. These are due to power imbalances across governance levels that reflect broader institutional differences between federal and decentralized systems of government. In addition, powerful communities operating predominantly at the national level hamper cross-level interactions. The analysis also reveals that engagement of national level actors is more extensive in the mitigation and that of local actors in the adaptation policy domain, and specialisation in one of the climate change responses at the national level hampers effective climate policy integration in the land use sector. [ABSTRACT FROM AUTHOR]

Land surface models are excellent tools for studying how climate change and land use affect surface hydrology. However, in order to assess the impacts of Earth processes on river flows, simulated changes in runoff need to be routed through the landscape. In this technical note, we describe the integration of the Ecosystem Demography (ED2) model with a hydrological routing scheme. The purpose of the study was to create a tool capable of incorporating to hydrological predictions the terrestrial ecosystem responses to climate, carbon dioxide, and land-use change, as simulated with terrestrial biosphere models. The resulting ED2+R model calculates the lateral routing of surface and subsurface runoff resulting from the terrestrial biosphere models' vertical water balance in order to determine spatiotemporal patterns of river flows within the simulated region. We evaluated the ED2+R model in the Tapajós, a 476674km² river basin in the southeastern Amazon, Brazil. The results showed that the integration of ED2 with the lateral routing scheme results in an adequate representation (Nash-Sutcliffe efficiency up to 0.76, Kling-Gupta efficiency up to 0.86, Pearson's R up to 0.88, and volume ratio up to 1.06) of daily to decadal river flow dynamics in the Tapajós. These results are a consistent step forward with respect to the "no river representation" common among terrestrial biosphere models, such as the initial version of ED2. [ABSTRACT FROM AUTHOR]

Aim To propose and compare priority sites for conservation and restoration of woody plants under diverse climate and land use scenarios, considering socio-economic costs, presence of protected areas and distribution of forest remnants. Location The Atlantic Forest Biodiversity Hotspot, Brazil. Methods We used ecological niche modelling to estimate geographical distributions for 2,255 species under current and future climate scenarios, which we analysed in relation to spatially explicit land use projections, maps of forest remnants derived from remote sensing and socio-economic variables for each municipality within the Atlantic Forest region. We identified spatial priorities that complement the current network of protected areas under three different prioritization scenarios: (1) conservation of existing forest remnants only; (2) conservation of remnants followed by restoration of degraded habitat; and (3) unconstrained actions, in which management location is not defined a priori. We compared our results under different levels of land protection, with targets of 10%, 17% and 20% of the Atlantic Forest extent. Results Current forest remnants cover only 12% of the Atlantic Forest, so targets of 17% and 20% were achieved only through active restoration. Targets of 17% and 20% captured most species and represented on average 26%-34% of species' distributions. The spatial pattern of degraded habitats negatively affected representation of biodiversity and implied higher costs and reduced efficiency of planning. We did not observe major differences between conservation prioritizations based on contrasting climate change scenarios. Main conclusions Protection of forest remnants alone will not suffice to safeguard woody plant species under climate and land use changes; therefore, restoration actions are urgently needed in the Atlantic Forest. With integrated management actions and multicriterion nationwide planning, reaching the 17% of land protection of Aichi biodiversity targets will constitute an important step towards protecting Atlantic Forest biodiversity. [ABSTRACT FROM AUTHOR]

Land use and climate change are expected to significantly alter hydrology and consequently electricity production in countries extremely dependent on their water resources, such as Brazil. Therefore, we used the large-scale hydrological model Soil and Water Assessment Tool (SWAT), which we integrated with climate change and land use scenarios for the Tocantins-Araguaia Watershed (TAW) with a focus on energy production at the Tucuruí Hydroelectric Plant (THP) in the southeastern Amazon. We used daily precipitation and temperature data from two General Circulation Models (GCM), HadGEM2-ES and MIROC5 with moderate (+4.5 W/m2 in the year 2100 relative to pre-industrial levels) and severe (+8.5 W/m2) radiative forcing from carbon dioxide emissions in the atmosphere (Representative Concentration Pathways). For the land use and land cover change (LULCC) scenario, we replaced forest areas only with pasture, then with agriculture, then with reforestation vegetation, and finally with regenerated forest. Each LULCC period was coupled with the highest impact climate scenario found for TAW (MIROC5-RCP 8.5); thus, we investigated five scenarios and their impacts on hydropower production and revenue in THP. Our results highlight that the TAW will face a large water reduction by the end of the century, which in all scenarios will strongly impact the basin's energy production and hydro revenue. Reductions of up to 74% in annual flow and 63% in electricity generation are expected for the most pessimistic scenario (L8.5), triggering a 135% deficit per year in THP revenue. Although some land use change scenarios partially minimize the climate-driven flow decrease trend in the period of higher precipitation, there is still a dramatic reduction in flow during the dry season, thus exacerbating seasonal and inter-annual variability. [Display omitted] • 74% reductions are expected for regional flow under LULC and Climate Change. • A flow deficit of up to 98% for the winter is expected in the worst-case climate scenario. • A reduction in energy production greater than 60% is expected for all scenarios. • A revenue loss of 135% was found for the coupled climate change and LULC scenario. • In the long-term climate change may have a greater impact than regional LULC on hydropower energy and revenues. [ABSTRACT FROM AUTHOR]

Addressing the global challenges of climate change (CC), food security and poverty alleviation requires enhancing the adaptive capacity and mitigation potential of land use systems. To this end, Climate Smart Agriculture (CSA) aims to identify land use practices that sustainably increase productivity, enhance climate change (CC) adaptation and contribute to CC mitigation. A transition towards CSA requires technical, but also socio-institutional changes, for improved smallholder agricultural systems. Such changes may be triggered by stakeholder participation processes that stimulate social learning and collective action. This article evaluates whether a role-playing game (RPG) is an effective participatory tool to encourage social learning and collective action among local stakeholders towards adoption of CSA strategies. We designed and implemented an RPG with three groups of farmers in Apuí (Southern Amazonas), evaluating the game's impact on social learning by interviewing each farmer before and after the RPG. Our findings show that the RPG induced not only technical learning, but also socio-institutional learning and engagement for collective action, though outcomes varied between different RPG sessions and among farmer participants. [ABSTRACT FROM AUTHOR]

The objective of this study was to analyze the spatial and temporal distribution of burned areas in Rondônia State, Brazil during the years 2000 to 2011 and evaluate the burned area maps. A Linear Spectral Mixture Model (LSMM) was applied to MODIS surface reflectance images to originate the burned areas maps, which were validated with TM/Landsat 5 and ETM+/Landsat 7 images and field data acquired in August 2013. The validation presented a correlation ranging from 67% to 96% with an average value of 86%. The lower correlation values are related to the distinct spatial resolutions of the MODIS and TM/ETM+ sensors because small burn scars are not detected in MODIS images and higher spatial correlations are related to the presence of large fires, which are better identified in MODIS, increasing the accuracy of the mapping methodology. In addition, the 12-year burned area maps of Rondônia indicate that fires, as a general pattern, occur in areas that have already been converted to some land use, such as vegetal extraction, large animal livestock areas or diversified permanent crops. Furthermore, during the analyzed period, land use conversion associated with climatic events significantly influenced the occurrence of fire in Rondônia and amplified its impacts. [ABSTRACT FROM AUTHOR]

Assessing the relative contribution of Land Use and Cover Changes (LUCC) and climate changes on runoff still represents a great challenge for water resources management. This issue is particularly critical for the Upper Paraná River Basin (UPRB), one of the most important basins in South America and responsible for most of the production of food, ethanol, and electricity generation in Brazil. In this paper, we used the Soil and Water Assessment Tool (SWAT) to quantitatively assess the relative contribution of both forcings. The simulation period included a time of great importance for climate studies, known as the 1970s global climate shift, and of great impact on river discharge within the UPRB. Three land use and cover scenarios were assigned to the 1961–1990 period of simulations, representing land use and cover during a pristine period (around the Year 1500), 1960, and 1985. Thirteen years of precipitation before and after the climate shift (considered to be the period 1974–1977) were analyzed and compared. Results showed a precipitation increase for the basin in general after the climate shift. The increase in rainfall reached up to 15% in many northern areas and more than 20% in the southern parts of the basin. By comparing all simulations, results indicate that both LUCC and precipitation increase due to the climate shift had a significant effect on the changes in annual discharge of the largest rivers of the UPRB. However, the results suggest that the impact of the precipitation increase on the discharge exceeded that of the LUCC. Between 1960 and 1985 the LUCC accounts for about 16% of the increase of the median annual discharge, whereas climate shift accounts for an increase of about 32%. These findings, suggesting a more relevant role for the climate, are consistent with two recent water crisis experienced by the country in the last decades, caused by prolonged below-normal rainfall throughout 2001/2002 and again in 2014/2015. [Display omitted] • We simulated land use and cover from a pristine period (Year 1500), 1960, and 1985. • We evaluated the effects of precipitation change on discharge from 1961 to 1990. • Natural vegetation fell by more than half of the original area up to 1985. • Precipitation increased by more than 20% after the 1970s global climate shift. • Results suggest that climate shift is the main driver in increasing annual discharge. [ABSTRACT FROM AUTHOR]

The extremely high-streamflow events of the Paranaíba River basin are found to be associated with La Niña phenomenon during December-February (DJF). Extreme events are identified based on their persistent flow for seven days and more after taking retention time into consideration. The extremely high-streamflow events are associated with the La Niña years; 80% of the high streamflow events have occurred during La Niña phases. Therefore, a very-significant 80% and above correspondence of the La Niña events and the seasonal streamflow anomalies are found in DJF. Although climate variations have direct relationship with the rainfall, streamflow variations are considered as the surrogates to rainfalls. However, apart from climate variations the anthropogenic and land-use changes also influence streamflow variations. In this study, we have applied multivelocity TOPMODEL approach and residual trend analysis to examine the impact of land-use to the streamflow at the Fazenda Santa Maria gauge stations. However, the model residual trend analysis of the TOPMODEL approach cannot quantify the extent of land-use impact. Thus, La Niña phase is important components to understand and predict the streamflow variations in the Paranaíba River basin. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Climate change scenarios vary considerably over the Amazon region, with an extreme scenario projecting a dangerous (from the human perspective) increase of 3.8°°C in temperature and 30%% reduction in precipitation by 2050. The impacts of such climate change on Amazonian land-use dynamics, agricultural production, and deforestation rates are still to be determined. In this study, the authors make a first attempt to assess these impacts through a systemic approach, using a spatially explicit modeling framework to project crop yield and land-use/land-cover changes in the Brazilian Amazon by 2050. The results show that, without any adaptation, climate change may exert a critical impact on the yields of crops commonly cultivated in the Amazon (e.g., soybean yields are reduced by 44%% in the worst-case scenario). Therefore, following baseline projections on crop and livestock production, a scenario of severe regional climate change would cause additional deforestation of 181 000 km2 (++20%%) in the Amazon and 240 000 km2 (++273%%) in the Cerrado compared to a scenario of moderate climate change. Putting an end to deforestation in the Brazilian Amazon forest by 2020 (and of the Cerrado by 2025) would require either a reduction of 26%%--40%% in livestock production until 2050 or a doubling of average livestock density from 0.74 to 1.46 head per hectare. These results suggest that (i) climate change can affect land use in ways not previously explored, such as the reduction of yields entailing further deforestation, and (ii) there is a need for an integrated/multidisciplinary plan for adaptation to climate change in the Amazon. [ABSTRACT FROM AUTHOR]

The sensitivity of surface energy and water fluxes to recent land cover changes is simulated for a small region in northern Mato Grosso, Brazil. The Simple Biosphere Model (SiB2) is used, driven by biophysical parameters derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) at 250-m resolution, to compare the effects of different land conversion types. The mechanisms through which changes in vegetation alter surface fluxes of energy, momentum, water, and carbon are analyzed for both wet and dry seasons. It is found that morphological changes contribute to warming and drying of the atmosphere while physiological changes, particularly those associated with a plant¿s photosynthetic pathway, counterbalance or exacerbate the warming depending on the type of conversion and the season. Furthermore, this study¿s results indicate that initial clearing of evergreen and transition forest to bare ground increases canopy temperature by up to 1.7°C. For subsequent land use such as pasture or cropland, the largest effect is seen for the conversion of evergreen forest to C3 cropland during the wet season,with a 21% decrease of the latent heat flux and 0.4°C increase in canopy temperature. The secondary conversion of pasture to cropland resulted in slight warming and drying during the wet season driven mostly by the change in carbon pathway from C4 to C3. For all conversions types, the daily temperature range is amplified, suggesting that plants replacing forest clearing require more temperature tolerance than the trees they replace. The results illustrate that the effect of deforestation on climate depends not only on the overall extent of clearing but also on the subsequent land use type. [ABSTRACT FROM AUTHOR]

Seasonally dry tropical forests are strongly impacted by human activities such as agriculture and ranching, as well as variations in climate conditions. Soil nematodes are sensitive to these changes, given that soil and climate characteristics influence their survival and occurrence. We analyzed the changes in the structure of nematode communities in three different types of land use (agricultural areas, secondary forest and natural forest) in the Caatinga, at Catimbau National Park, Pernambuco, northeastern Brazil. We recorded a total of 17,177 nematode individuals belonging to 104 genera. Nematode abundance and richness were highest in the secondary forest and lowest in the agricultural areas. The total abundance of bacterivores and omnivore-predators was affected by types of land use. Different soil properties as well as monthly mean rainfall and temperature were strongly related to the differences in taxonomic composition among the agricultural areas, secondary forest and natural forest, accounting for 65.42% of the total variation. In general, our results indicate that agricultural activities in the Caatinga negatively affect the nematode communities, and that soil characteristics and climate variables also strongly affect the structure and composition of these communities. • The agricultural activities negatively affect the nematode communities. • The secondary forest regenerating increases the nematode abundance. • Bacterivorous nematodes Acrobeles spp. dominated in various types of land use. • The nematode composition was related to soil properties and climate variables. • The nematode community can be used to assess soil health in Caatinga. [ABSTRACT FROM AUTHOR]

Grazing areas represent the largest agricultural areas in Brazil, occupying more than 172 million hectares, about 20% of the agricultural land (IBGE, 2007). Despite the large areas of degraded pasture, little information exists about the temporal variation of soil properties including nutrients and soil carbon dynamic (Cerri et al., 2004). This study aimed to measure soil FCO 2 from degraded and managed pasture areas, describing their temporal variability correlated to the environmental variables. Our study was carried out at two pasture areas located in Mococa city, São Paulo State Brazil. On March 04, 2013, 2 grids of 100 × 100 m with 102 samples points were installed in DP (Degraded pasture) and managed pasture (MP). Measurements of soil CO 2 emissions (FCO 2 ), soil temperature (T soil ) and water content of soil (WC soil ) were initiated onMarch 12 th , resulting 8 measuring days. Higher difference of emission between both areasoccurred during the first days, probably due to a huge precipitation influence (accumulated 80 mm). In the first study day (12 th ), emission values were 8.73 ± 0.38 versus 4.47 ± 0.21 μmol m -2 s -1 , in DP and MP, respectively. In the last study day, March 19 th , emissions in both areas were closer without remarkable rain influence (7.43 ± 0.54 and 5.98 ± 0.17 μmol m -2 s -1 ). Total emission calculated by the area bellow the emission curves resulted 640.7 versus 440.0 kg CO 2 -C ha -1 in DP and MP, respectively, corresponding to an additional emission of 200.6 kg CO 2 -C ha -1 from DP or, 735.5 kg CO 2 released to the atmosphere, contributing to the Climate Change. The potential for soil C sequestration in pasture soils is strictly related to their management, and the rate and mechanism of soil C losses in pasture soils can affect this potential, with soils functioning as an atmospheric CO 2 sinking or emitter. [ABSTRACT FROM AUTHOR]