Search

Land use change (LUC) is a main cause of global environmental change, and is an important activity to be studied. Our research aims to examine the current state of evidence on the link between LUC and human health in the Amazon region. We conducted a scoping review of literature in two research databases, resulting in 14 papers for analysis. Our analysis demonstrated a lack of clear definitions for LUC, a wide variety of negative health effects from LUC, the lack of qualitative articles, a lack of studies exploring the potential positive health effects of LUC, and the predominance of studies coming from the Brazilian Amazon. Our study validated the prevailing idea that LUC can lead to negative health consequences, if not managed properly. [ABSTRACT FROM AUTHOR]

This paper compares land use patterns of mestizo colonists and indigenous populations in the central Ecuadorian Amazon, based on data from a household survey covering mestizo colonist, Kichwa and Shuar households. As expected, colonists mostly engage in commercial agriculture and cattle ranching, but there are substantial differences in land use patterns between the Shuar and the Kichwa. The Shuar engage in cash cropping and cattle ranching, and on average, devote even more land to agricultural uses than mestizo colonists in this sample. In contrast, the Kichwa engage more in subsistence crop production and less in commercial agriculture. Such different patterns appear related to local conditions, earlier migratory and settlement patterns, and the level of exposure to markets. The implications of this for policy are explored in the conclusions. [ABSTRACT FROM AUTHOR]

Indigenous traditional land uses, including hunting, fishing, sacred activities, and land-based education at the Red Sucker Lake First Nation (RSLFN) in Manitoba, Canada, are impacted by mining. The Red Sucker Lake First Nation (RSLFN) people want their territories' land and water to be protected for traditional uses, culture, and ecological integrity. Towards this goal, their Island Lake Tribal Council sought support for an Indigenous-protected and conserved area (IPCA) in their territory, outside of existing mining claims, but without success. The two-eyed seeing approach was adopted in this study. Traditional land use mapping and interviews were undertaken with 21 Indigenous people from the RSLFN, showing that many traditional land uses are concentrated on greenstone belts. The interviews revealed that mining exploration has resulted in large petroleum spills, noise distress, private property destruction, wildlife die-offs, and animal population declines. These issues negatively impact RSLFN's traditional land use practices, ecosystem integrity, and community health. Governments need to partner with Indigenous communities to reach their biodiversity targets, particularly considering northern Canada's peatlands, including those in the RSLFN territory, surpassing Amazon forests for carbon storage. The role of critical minerals in renewable energy and geopolitics has colonial governments undermining Indigenous rights, climate stabilization, and biodiversity to prioritize extractivism. Mining at the RSLFN has environmental impacts from exploration to decommissioning and after, as well as the massive infrastructure required that includes roads, hydro, and massive energy supplies, with a proposed multimedia national Northern Corridor to export RSLFN's resources and other resources to six ports. [ABSTRACT FROM AUTHOR]

Biogeochemistry is hosting this special thematic issue devoted to studies of land-water interactions, as part of the Large-scale Biosphere-Atmosphere Experiment in Amazônia (LBA). This compilation of papers covers a broad range of topics with a common theme of coupling land and water processes, across pristine and impacted systems. Findings highlighted that hydrologic flowpaths are clearly important across basin size and structure in determining how water and solutes reach streams. Land-use changes have pronounced impacts on flowpaths, and subsequently, on stream chemistry, from small streams to large rivers. Carbon is produced and transformed across a broad array of fluvial environments and wetlands. Surface waters are not only driven by, but provide feedback to, the atmosphere. [ABSTRACT FROM AUTHOR]

Since the 1970s, migration to the Amazon has led to a growing human presence and resulting dramatic changes in the physical landscape of the Northern Ecuadorian Amazon frontier, including considerable deforestation. Over time, a second demographic phenomenon has emerged with the children of the original migrants leaving settler farms to set out on their own. The vast majority have remained in the Amazon region, some contributing to further changes in land use via rural–rural migration to establish new farms and others to incipient urbanization. This paper uses longitudinal, multi-scale data on settler colonists between 1990 and 1999 to analyze rural–rural and rural–urban migration among second-generation colonists within the region. Following a description of migrants and settlers in terms of their individual, household and community characteristics, a multinomial discrete-time hazard model is used to estimate the determinants of out-migration of the second generation settlers to both urban and rural areas. We find significant differences in the determinants of migration to the two types of destinations in personal characteristics, human capital endowments, stage of farm and household lifecycles, migration networks, and access to community resources and infrastructure. The paper concludes with a discussion of policy implications of migrants’ choice of rural versus urban destinations. [ABSTRACT FROM AUTHOR]

The Brazilian Amazon forest and cerrado savanna encompasses a region of enormous ecological, climatic, and land-use variation. Satellite remote sensing is the only tractable means to measure the biophysical attributes of vegetation throughout this region, but coarse-resolution sensors cannot resolve the details of forest structure and land-cover change deemed critical to many land-use, ecological, and conservation-oriented studies. The Carnegie Landsat Analysis System (CLAS) was developed for studies of forest and savanna structural attributes using widely available Landsat Enhanced Thematic Mapper Plus (ETM+) satellite data and advanced methods in automated spectral mixture analysis. The methodology of the CLAS approach is presented along with a study of its sensitivity to atmospheric correction errors. CLAS is then applied to a mosaic of Landsat images spanning the years 1999–2001 as a proof of concept and capability for large-scale, very high resolution mapping of the Amazon and bordering cerrado savanna. A total of 197 images were analyzed for fractional photosynthetic vegetation (PV), nonphotosynthetic vegetation (NPV), and bare substrate covers using a probabilistic spectral mixture model. Results from areas without significant land use, clouds, cloud shadows, and water bodies were compiled by the Brazilian state and vegetation class to understand the baseline structural typology of forests and savannas using this new system. Conversion of the satellite-derived PV data to woody canopy gap fraction was made to highlight major differences by vegetation and ecosystem classes. The results indicate important differences in fractional photosynthetic cover and canopy gap fraction that can now be accounted for in future studies of land-cover change, ecological variability, and biogeochemical processes across the Amazon and bordering cerrado regions of Brazil. [ABSTRACT FROM AUTHOR]

This paper addresses the Amazonian shortwave radiative budget over cloud-free conditions after considering three aspects of deforestation: (i) the emission of aerosols from biomass burning due to forest fires; (ii) changes in surface albedo after deforestation; and (iii) modifications in the column water vapour amount over deforested areas. Simultaneous Clouds and the Earth's Radiant Energy System (CERES) shortwave fluxes and aerosol optical depth (AOD) retrievals from the Moderate Resolution Imaging Spectro-Radiometer (MODIS) were analysed during the peak of the biomass burning seasons (August and September) from 2000 to 2009. A discrete-ordinate radiative transfer (DISORT) code was used to extend instantaneous remote sensing radiative forcing assessments into 24-h averages. The mean direct radiative forcing of aerosols at the top of the atmosphere (TOA) during the biomass burning season for the 10-yr studied period was -5.6 ± 1.7 W m-2. Furthermore, the spatial distribution of the direct radiative forcing of aerosols over Amazonia was obtained for the biomass burning season of each year. It was observed that for high AOD (larger than 1 at 550 nm) the maximum daily direct aerosol radiative forcing at the TOA may be as high as -20 W m-2 locally. The surface reflectance plays a major role in the aerosol direct radiative effect. The study of the effects of biomass burning aerosols over different surface types shows that the direct radiative forcing is systematically more negative over forest than over savannah-like covered areas. Values of -15.7 ± 2.4 W m-2/τ550nm and -9.3 ± 1.7 W m-2/τ550nm were calculated for the mean daily aerosol forcing efficiencies over forest and savannah-like vegetation respectively. The overall mean annual land use change radiative forcing due to deforestation over the state of Rondônia, Brazil, was determined as -7.3 ± 0.9 W m-2. Biomass burning aerosols impact the radiative budget for approximately two months per year, whereas the surface albedo impact is observed throughout the year. Because of this difference, the estimated impact in the Amazonian annual radiative budget due to surface albedo-change is approximately 6 times higher than the impact due to aerosol emissions. The influence of atmospheric water vapour content in the radiative budget was also studied using AERONET column water vapour. It was observed that column water vapour is on average smaller by about 0.35 cm (around 10% of the total column water vapour) over deforested areas compared to forested areas. Our results indicate that this drying contributes to an increase in the shortwave radiative forcing, which varies from 0.4 W m-2 to 1.2 W m-2 depending on the column water vapour content before deforestation. The large radiative forcing values presented in this study point out that deforestation could have strong implications in convection, cloud development and the ratio of direct to diffuse radiation, which impacts carbon uptake by the forest. [ABSTRACT FROM AUTHOR]

This paper analyses poverty and inequality dynamics among smallholders along the Transamazon Highway. We measure changes in poverty and inequality for original settlers and new owners, contrasting income-based with multidimensional indices of well-being. Our results show an overall reduction in both poverty and inequality among smallholders, although poverty decline was more pronounced among new owners, while inequality reduction was larger among original settlers. This trend suggests that families have an initial improvement in livelihood and well-being which tends to reach a limit later-a sign of structural limitations common to rural areas and maybe a replication of boom and bust trends in local economies among Amazonian municipalities. In addition, our multidimensional estimates of well-being reveal that some economically viable land use strategies of smallholders (e.g., pasture) may have important ecological implications for the regional landscape. These findings highlight the public policy challenges for fostering sustainable development among rural populations. [ABSTRACT FROM AUTHOR]

The present paper describes the contentious process of settlement formation of a particular type of land reform settlement, which we call "spontaneous" direct action land reform. In addition, the paper place the settlement formation process within a land cover and land use framework by describing the underlying processes that lead to spontaneous settlement formation in terra devoluta in the Brazilian Amazon. The paper concludes with policy recommendations. [ABSTRACT FROM AUTHOR]

While interest in Amazonian deforestation mostly focuses on frontier areas, the amount of forest cover in areas already dominated by human settlement is also changing. Secondary forests play an increasingly important role for maintaining genetic diversity, hydrological functioning, and greenhouse gas emissions of altered landscapes, but secondary forests are also being converted to more intensive agricultural uses. Five dates of Landsat imagery from 1984 to 2002 were analyzed, covering 8000 km2 of the Zona Bragantina of the eastern part of the Brazilian state of Pará, which underwent its most intensive wave of deforestation several decades ago. However, even in this area of relatively long-term human occupation, ongoing decreases of forest cover were found, both in the small remaining areas of mature forest and in the more widespread areas of secondary forests, as human population increased and land use intensified. Although there was an initial increase in the area of secondary forest from 1984 to 1994, there has been a steady decline since then, from 75% secondary forest cover in 1994 to 54% in 2002. The amount of pasture was relatively stable from 1984 to 1994 but more recently has shown a steady increase, reaching 37% cover in 2002. The average rate of carbon loss over the 18-yr study period was 0.9 Mg C ha-1 yr-1 for the 8000 km2 study area. Forests in this long-settled region of eastern Amazonia continue to be degraded, resulting in the loss of ecosystem services and carbon stocks due to continued land-use change. [ABSTRACT FROM AUTHOR]

As data sets of multiple types and scales proliferate, it will be increasingly important to be able to flexibly combine them in ways that retain relevant information. A case in point is Amazonia, a large, data-poor region where most whole-basin data sets are limited to understanding land cover interpreted through a variety of remote sensing techniques and sensors. A growing body of work, however, indicates that the future state of much of Amazonia depends on the land use to which converted areas are put, but land use in the tropics is difficult to assess from remotely sensed data alone. An earlier paper developed new snapshots of agricultural land use in this region using a statistical fusion of satellite data and agricultural census data, an underutilized ancillary data source available across Amazonia. The creation of these land-use maps, which have the spatial detail of a satellite image and the attribute information of an agricultural census, required the development of a new statistical technique for merging data sets at different scales and of fundamentally different data types. Here we describe and assess this nonlinear technique, which reinterprets existing land cover classifications by determining what categories are most highly related to the polygon land-use data across the study area. Although developed for this region, the technique appears to hold broad promise for the systematic fusion of multiple data sets that are closely related but of different origins. [ABSTRACT FROM AUTHOR]

Most research featuring demographic factors in environmental change has focused on processes operating at the level of national or global populations. This paper focuses on household-level demographic life cycles among colonists in the Amazon, and evaluates the impacts on land use allocation. The analysis goes beyond prior research by including a broader suite of demographic variables, and by simultaneously assessing their impacts on multiple land uses with different economic and ecological implications. We estimate a system of structural equations that accounts for endogeneity among land uses, and the findings indicate stronger demographic effects than previous work. These findings bear implications for modeling land use, and the place of demography in environmental research. [ABSTRACT FROM AUTHOR]

Land tenure has been considered one of the key factors that define patterns and change in land-use systems. This paper examines the implications of land reform for household decisions regarding patterns of land use, agricultural intensification, and forest conservation. We look at an Amazonian caboclo settlement in the Lower Amazon that had experienced land reform by the end of the 1980s. Results show that defined land tenure is not enough to guarantee agricultural intensification and forest conservation. In fact, several factors working at different scales are affecting land-use change in the region. At the settlement level, privatization of upland forest has led to an overall increase in cultivated land—pasture and annual crops—and increasing deforestation rates. However, at the farm-property level, different systems of agricultural production—intensive, extensive, or abandonment of land—occur according to availability of labor, and capital, and access to different natural resources. [ABSTRACT FROM AUTHOR]

Despite new research on agricultural intensification, we still have limited knowledge of the determinants of technology adoption in low-density, limitedmarket regions, particularly in humid tropical forests. This lacuna has led to divergent opinions about the impacts of intensification on land use in the Brazilian Amazon, well-known for deforestation of fragile tropical ecosystems. This paper takes up the case of the Amazon to address two questions concerning the adoption of agricultural technologies: 1) what are its social determinants, and 2) what are its land use correlates. Empirical data come from a recent survey of smallholders along the Transamazon highway. The first part of the analysis, consisting of models of eight agricultural technologies, shows that households with more labor and capital are more likely to adopt technologies. The second part shows that for all technologies, adopters have more land cleared than do non-adopters. These findings raise questions for further research on intensification while also suggesting policy prescriptions to mitigate deforestation. [ABSTRACT FROM AUTHOR]

Our aim with this paper is to present a novel approach for developing story lines and scenarios by combining qualitative knowledge and quantitative data from different disciplines and discussing the results with relevant decision makers. This research strategy offers a solid foundation for perspectives into the future. The "laboratory" is the Brazilian Amazon, one of the hotspots of land-use change where local and global interests both collide and converge: local livelihoods are affected by regional and global climate change and by the loss of biodiversity caused by local and global economic interests in agro-industrial land use; such use contributes, in turn, to climate change. After decades of diverse policy interventions the question arises: What can we learn from past trajectories for a more sustainable development in the future? To answer this question, we combined qualitative story lines for the region, reviewed by local experts, with quantitative land-use scenarios, to study their regional and local manifestations in space. These results were then discussed again with local and national experts. Our findings suggest that in-depth knowledge of the diverging perspectives at a very local level is a fundamental prerequisite for downscaling global scenarios and upscaling local approaches to sustainable land-use management and thus, to producing communicable and applicable results. [ABSTRACT FROM AUTHOR]

The Brazilian Amazonian Forest is undergoing significant changes in land use and land cover in the last few decades. This land-use transition, besides climate change, may be responsible for the fire regime transition in this territory. Therefore, we aimed at investigating how the fire-transition occurs over time in the Brazilian Amazonia Forest and identifying the key parameters that can help to predict this change. For this, we collected yearly data on fire occurrence, forest cover, deforestation rates, and cropland areas. We used a 0.45° spatial surface grid, and with these annual values, we produced: (i) generalised linear mixed models of fire occurrence against forest cover, using years and grids as random factors; (ii) annual linear models of fire occurrence against forest cover; (iii) linear models of the apex values against the years; and (iv) generalised linear models of these apex values against deforestation and cropland areas. We found that there is a fire-transition process in the Brazilian Amazon Forest since a quadratic model better predicted the fire occurrence behaviour. Moreover, the fire occurrence apex is transitioning to more forested landscapes, from 50.7% in 2003 to 55% in 2019 (R² = 0.3). The deforestation rates and the cropland expansion had important relationships with the fire-transition, the first is related to the fire occurrence in the landscape (R² = 0.62), while the second better predicts the transition to more forested areas (R² = 0.38). Thus, we found that the fire-transition in the Brazilian Amazon Forest is strongly related to the land-use transition stages in this region. [ABSTRACT FROM AUTHOR]

Safeguarding tropical forest biodiversity requires solutions for monitoring ecosystem structure over time. In the Amazon, logging and fire reduce forest carbon stocks and alter habitat, but the long-term consequences for wildlife remain unclear, especially for lesserknown taxa. Here, we combined multiday acoustic surveys, airborne lidar, and satellite time series covering logged and burned forests (n = 39) in the southern Brazilian Amazon to identify acoustic markers of forest degradation. Our findings contradict expectations from the Acoustic Niche Hypothesis that animal communities in more degraded habitats occupy fewer “acoustic niches” defined by time and frequency. Instead, we found that aboveground biomass was not a consistent proxy for acoustic biodiversity due to the divergent patterns of “acoustic space occupancy” between logged and burned forests. Ecosystem soundscapes highlighted a stark, and sustained reorganization in acoustic community assembly after multiple fires; animal communication networks were quieter, more homogenous, and less acoustically integrated in forests burned multiple times than in logged or once-burned forests. These findings demonstrate strong biodiversity cobenefits from protecting burned Amazon forests from recurrent fire. By contrast, soundscape changes after logging were subtle and more consistent with acoustic community recovery than reassembly. In both logged and burned forests, insects were the dominant acoustic markers of degradation, particularly during midday and nighttime hours, which are not typically sampled by traditional biodiversity field surveys. The acoustic fingerprints of degradation history were conserved across replicate recording locations, indicating that soundscapes may offer a robust, taxonomically inclusive solution for digitally tracking changes in acoustic community composition over time. [ABSTRACT FROM AUTHOR]

This paper studies the dynamics of land-use in the Brazilian Amazon using a structural vector autoregressive (SVAR) model. A fixed effect panel data specification is used to control for the heterogeneity in the data. Meanwhile, spatial autocorrelation is also diagnosed by a statistical methodology that allows us to split the model in subsamples (clusters) of more homogenous municipalities. The clustering analysis shows that there are three clusters whose land-use patterns are strongly different in an economical point of view. The first cluster identifies municipalities dedicated to logging, natural resources exploitation and slash-and-burn cultures; the second cluster shows a more diversified agriculture; while the third cluster presents very developed intensive agriculture municipalities. Another contribution of this article relies on the assessment of contemporaneous causal relation among distinct land-uses areas. This new approach allows us to evaluate the dynamics relations arisen from unexpected innovations in the process of soil occupation. The impulse response functions (IRF) and the forecast error variance decompositions (FEVD) generate the following results: (1) in the opposition direction of previous studies, we find that the demand for cropping does not require to clear new areas of forest.; (2) contrary to previous studies we do not find indication that cattle ranching is the primary driver of deforestation; (3) the impact of a shock of pasture land on itself is virtually null at the initial stages, but increases over time, not requiring to clear extra areas of forest land but rather competing with crop land; (4) it seems that if not for all the Amazon Basin, at least in one cluster, cattle ranching and cropping could be competitive activities; and (5) we find out that in the long run pasture innovation is responsible for the major percent of the forecast error concern all land uses. It probably means that the destiny of distinct categories of land, in cluster one, is endogenously determine by activities connected to cattle. [Copyright &y& Elsevier]

Abstract: This paper analyzes the impact of agricultural technical efficiency on the propensity of farmers to convert natural land into agricultural plots, i.e., to deforest, in the Brazilian Legal Amazon (BLA). A two-step econometric approach is adopted. A bootstrapped translog stochastic frontier that is a posteriori checked for functional consistency is used to assess technical efficiency and these estimates are put into a land-use model to assess the impact of productivity on deforestation. Analysis of agricultural census tract data suggests that technical efficiency has a U-shaped effect: both less and more efficient farms use more land for their agricultural activities and so have a positive effect on deforestation. However, the majority of farms in the BLA are on the ascendant slope, so that efficiency implies more deforestation in the BLA. The poor environmental valuation of the Brazilian forest, the uneven land distribution, and the problem of the de facto openly accessed forested and “unproductive” lands in the BLA could explain the U-shaped effect of technical efficiency on the conversion of forested land into agricultural land. [Copyright &y& Elsevier]

The process of human occupation in Brazilian Amazonia is heterogeneous in space and time. The goal of this paper is to explore intra-regional differences in land-use determining factors. We built spatial regression models to assess the determining factors of deforestation, pasture, temporary and permanent agriculture in four space partitions: the whole Amazon; the Densely Populated Arch (southern and eastern parts of the Amazon), where most deforestation has occurred; Central Amazon, where the new frontiers are located; and Occidental Amazon, still mostly undisturbed. Our land-use data combines deforestation maps derived from remote sensing and 1996 agricultural census. We compiled a spatially explicit database with 50 socio-economic and environmental potential factors using 25km×25km regular cells. Our results show that the concentrated deforestation pattern in the Arch is related to the diffusive nature of land-use change, proximity to urban centers and roads, reinforced by the higher connectivity to the more developed parts of Brazil and more favorable climatic conditions, expressed as intensity of the dry season. Distance to urban centers was used as a proxy of accessibility to local markets, and was found to be as important as distance to roads in most models. However, distance to roads and to urban centers does not explain intra-regional differences, which were captured by other factors, such as connection to national markets and more favorable climatic conditions in the Arch. Agrarian structure results show that areas in which the land structure is dominated by large and medium farms have a higher impact on deforestation and pasture extent. Temporary and permanent agriculture patterns were concentrated in areas where small farms are dominant. We conclude that the heterogeneous occupation patterns of the Amazon can only be explained when combining several factors related to the organization of the productive systems, such as favorable environmental conditions and access to local and national markets. Agrarian structure and land-use analysis reinforced this conclusion, indicating the heterogeneity of land-use systems by type of actor, and the influence of the agrarian structure on land-use patterns across the region. [Copyright &y& Elsevier]

Land use and cover of the Northeastern Ecuadorian Amazon has changed significantly over the last 40 years. These well-documented changes are slowly modifying the physical environment of the region from one dominated by the classic humid tropics to one more reminiscent of the eastern Amazon basin with cyclical moisture and temperature gradients, consequent emergent fire regimes and persistent deforestation. This paper discusses the causes of local land use and cover change, the remote sensing and sampling methods employed that led to the discovery of burned areas, and presents a physical climatology of diffusion and convection to explain the presence of burned areas in the traditionally fire immune humid tropical Ecuadorian Amazon. [ABSTRACT FROM AUTHOR]

This paper describes four global-change phenomena that are having major impacts on Amazonian forests. The first is accelerating deforestation and logging. Despite recent government initiatives to slow forest loss, deforestation rates in Brazilian Amazonia have increased from 1.1 million ha yr-1 in the early 1990s, to nearly 1.5 million ha yr-1 from 1992–1994, and to more than 1.9 million ha yr-1 from 1995–1998. Deforestation is also occurring rapidly in some other parts of the Amazon Basin, such as in Bolivia and Ecuador, while industrialized logging is increasing dramatically in the Guianas and central Amazonia. The second phenomenon is that patterns of forest loss and fragmentation are rapidly changing. In recent decades, large-scale deforestation has mainly occurred in the southern and eastern portions of the Amazon — in the Brazilian states of Pará, Maranhāo, Rondônia, Acre, and Mato Grosso, and in northern Bolivia. While rates of forest loss remain very high in these areas, the development of major new highways is providing direct conduits into the heart of the Amazon. If future trends follow past patterns, land-hungry settlers and loggers may largely bisect the forests of the Amazon Basin. The third phenomenon is that climatic variability is interacting with human land uses, creating additional impacts on forest ecosystems. The 1997/98 El Niño drought, for example, led to a major increase in forest burning, with wildfires raging out of control in the northern Amazonian state of Roraima and other locations. Logging operations, which create labyrinths of roads and tracks in forsts, are increasing fuel loads, desiccation and ignition sources in forest interiors. Forest fragmentation also increases fire susceptibility by creating dry, fire-prone forest edges. Finally, recent evidence suggests that intact Amazonian forests are a globally significant carbon sink, quite possibly caused by higher forest growth rates in response to increasing atmospheric CO2 fertilization. Evidence for a carbon sink comes from long-term forest mensuration plots, from whole-forest studies of carbon flux and from investigations of atmospheric CO2 and oxygen isotopes. Unfortunately, intact Amazonian forests are rapidly diminishing. Hence, not only is the destruction of these forests a major source of greenhouse gases, but it is reducing their intrinsic capacity to help buffer the rapid anthropogenic rise in CO2. [ABSTRACT FROM AUTHOR]

In the Amazon rainforest, land use following deforestation is diverse and dynamic. Mounting evidence indicates that the climatic impacts of forest loss can also vary considerably, depending on specific features of the affected areas. The size of the deforested patches, for instance, was shown to modulate the characteristics of local climatic impacts. Nonetheless, the influence of different types of land use and management strategies on the magnitude of local climatic changes remains uncertain. Here, we evaluated the impacts of large-scale commodity farming and rural settlements on surface temperature, rainfall patterns, and energy fluxes. Our results reveal that changes in land-atmosphere coupling are induced not only by deforestation size but also, by land use type and management patterns inside the deforested areas. We provide evidence that, in comparison with rural settlements, deforestation caused by large-scale commodity agriculture is more likely to reduce convective rainfall and increase land surface temperature. We demonstrate that these differences are mainly caused by a more intensive management of the land, resulting in significantly lower vegetation cover throughout the year, which reduces latent heat flux. Our findings indicate an urgent need for alternative agricultural practices, as well as forest restoration, for maintaining ecosystem processes and mitigating change in the local climates across the Amazon basin. [ABSTRACT FROM AUTHOR]

Land conversion and changing climate are expected to significantly alter tropical forest hydrology. We used a land surface model integrated with a river routing scheme to analyze the hydrological alterations expected in the Tapajós River basin, a large portion of the Brazilian Amazon, caused by two environmental drivers: climate and land use. The model was forced with two future climate scenarios (years 2026–2045) from the Earth System Model HadGem2‐ES with moderate (+4.5 W/m2 radiative forcing value in the year 2100 with respect to preindustrial levels) and severe (+8.5 W/m2) representative atmospheric carbon dioxide pathways (Representative Concentration Pathways). We tested the sensitivity of our results to the uncertainty in future climate projections by running simulations with IPSL‐CM5 (wettest scenarios) and GISS‐E2 (driest scenarios). Human land use effects on vegetation were evaluated using a limited and an extreme deforestation scenario. Our analysis indicates that climate change is predicted to reduce river flows across seasons (up to 20%) and bring a considerable shift in flow seasonality toward a later onset (nearly 1.5 months) and increase in interannual variability. While land use change partially counteracts the climate‐driven diminishing trend in river flows, it is expected to contribute to a further increase in interannual and intraannual variability. From a water management perspective, the overall reduction of river flows and their increased variability, combined with the shift and the shortening of the wet season, could potentially affect the productivity of the large hydropower systems planned for the region and the growing demand for agricultural and transport expansion. Plain Language Summary: Climate and land use change are expected to heavily modify the water cycle. This is particularly true in tropical areas, where human‐driven changes may completely alter river discharge. The Amazon is the largest of the remaining tropical forests. Increasing agriculture and livestock production have significantly altered land cover in the region. This pattern is projected to continue in the coming decades. The change in the Amazon's future is highly uncertain: the direct effects of climate and land use change are not well understood and the response also depends on complex Earth‐atmosphere exchanges. We used computer models representing water and energy cycles over time to understand how environmental changes are likely to alter the discharge of the Tapajós River system in southeastern Amazon. By combining two climate and two land use scenarios, we found that climate change is expected to reduce the river flows in the basin, bringing a delay in the flow seasonality and increasing the overall variability. Land use change, conversely, is expected to cause an increase in flow magnitude and variability. Besides the serious environmental consequences, these findings have important implications for the management and development of water in this strategic area for Brazil's energy and food production. Key Points: Biosphere model simulations of future climate and land use change in southeastern Amazon allow to study the impact of local, regional, and global environmental changes on the basin's surface water hydrologyClimate change is predicted to reduce river flows, delaying the rainy season and increasing variabilityLand use change is expected to partially offset climate change impact on river flows in the short term [ABSTRACT FROM AUTHOR]

Copyright of Cuadernos de Geografia: Revista Colombiana de Geografía is the property of Universidad Nacional de Colombia 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.)

Protected areas (PAs) remain the dominant policy to protect biodiversity and ecosystem services but have been shown to have limited impact when development interests force them to locations with lower deforestation pressure. Far less known is that such interests also cause widespread tempering, reduction, or removal of protection [i.e., PA downgrading, downsizing, and degazettement (PADDD)]. We inform responses to PADDD by proposing and testing a bargaining explanation for PADDD risks and deforestation impacts. We examine recent degazettements for hydropower development and rural settlements in the state of Rondônia in the Brazilian Amazon. Results support two hypotheses: (i) ineffective PAs (i.e., those where internal deforestation was similar to nearby rates) were more likely to be degazetted and (ii) degazettement of ineffective PAs caused limited, if any, additional deforestation. We also report on cases in which ineffective portions were upgraded. Overall our results suggest that enhancing PAs' ecological impacts enhances their legal durability. [ABSTRACT FROM AUTHOR]

The Amazon rainforest is disproportionately important for global carbon storage and biodiversity. The system couples the atmosphere and land, with moist forest that depends on convection to sustain gross primary productivity and growth. Earth system models that estimate future climate and vegetation show little agreement in Amazon simulations. Here we show that biases in internally generated climate, primarily precipitation, explain most of the uncertainty in Earth system model results; models, empirical data and theory converge when precipitation biases are accounted for. Gross primary productivity, above-ground biomass and tree cover align on a hydrological relationship with a breakpoint at ~2000mm annual precipitation, where the system transitions between water and radiation limitation of evapotranspiration. The breakpoint appears to be fairly stable in the future, suggesting resilience of the Amazon to climate change. Changes in precipitation and land use are therefore more likely to govern biomass and vegetation structure in Amazonia. [ABSTRACT FROM AUTHOR]

For half a century, the process of economic integration of the Amazon has been based on intensive use of renewable and nonrenewable natural resources, which has brought significant basin-wide environmental alterations. The rural development in the Amazonia pushed the agricultural frontier swiftly, resulting in widespread land-cover change, but agriculture in the Amazon has been of low productivity and unsustainable. The loss of biodiversity and continued deforestation will lead to high risks of irreversible change of its tropical forests. It has been established by modeling studies that the Amazon may have two "tipping points," namely, temperature increase of 4 °C or deforestation exceeding 40% of the forest area. If transgressed, large-scale "savannization" of mostly southern and eastern Amazon may take place. The region has warmed about 1 °C over the last 60 y, and total deforestation is reaching 20% of the forested area. The recent significant reductions in deforestation--80% reduction in the Brazilian Amazon in the last decade--opens up opportunities for a novel sustainable development paradigm for the future of the Amazon. We argue for a new development paradigm--away from only attempting to reconcile maximizing conservation versus intensification of traditional agriculture and expansion of hydropower capacity--in which we research, develop, and scale a high-tech innovation approach that sees the Amazon as a global public good of biological assets that can enable the creation of innovative high-value products, services, and platforms through combining advanced digital, biological, and material technologies of the Fourth Industrial Revolution in progress. [ABSTRACT FROM AUTHOR]

Reconstruction of Highway BR-319 (Manaus-Porto Velho) would allow for access from the 'arc of deforestation' in the southern part of Brazil's Amazon region to vast blocks of forests in central and northern Amazonia. Building roads is known to be a major driver of deforestation, allowing entry of squatters, and other actors. Rather than deforestation along the highway route, here we consider the road's potential for stimulating deforestation in a separate location, approximately 550 km north of BR-319's endpoint in Manaus. Reconstructing BR-319 has great potential impact to start a new wave of migration to this remote region. The southern portion of the state of Roraima, the focus of our study, is already connected to Manaus by Highway BR-174. We modeled deforestation in southern Roraima and simulated carbon emissions between 2007 and 2030 under four scenarios. Simulations used the AGROECO model in DINAMICA-EGO © software. Two scenarios were considered with reconstruction of BR-319 and two without this road connection. For each of the two possibilities regarding BR-319, simulations were developed for (1) a 'conservation' (CONSERV) scenario that assumes the creation of a series of protected areas, and (2) a 'business-as-usual' (BAU) scenario that assumes no additional protected areas. Results show that by 2030, with BR-319 rebuilt, deforestation carbon emissions would increase between 19 % (CONSERV) and 42 % (BAU) over and above those corresponding to no-road scenarios. [ABSTRACT FROM AUTHOR]

Changes in settlement patterns have influenced food-production systems and territorial organization in western Amazonia, and landing strips have affected current land-use patterns in indigenous territories in the region. In this study we characterize riverine and interfluvial production systems in the lower Pastaza River Basin in Ecuador, using historical ethnographic records, remotely sensed data, surveyed information, and statistical descriptions. Results show that nucleation of settlements around landing strips has increased indigenous people's control over their ancestral territories and changed the political and geographical landscape. At the same time, nucleation is slowly transforming indigenous livelihoods from mobile cultivation and foraging to sedentary farming. Even though indigenous communities will eventually become integrated into the national economy, the main elements of the traditional food-production system will likely remain the same. Development policies should respond to local land-management strategies in order to ensure the long-term sustainability of Amazonian socioecological systems. [ABSTRACT FROM AUTHOR]

We evaluated the effects of different land-use systems on the ability of dung beetles to control the population of detritus-feeding flies. We tested the hypotheses that intensification of land use will reduce dung beetles richness, abundance and biomass and, consequently, their dung burial ability, affecting the interaction between dung beetles and flies and reducing its effectiveness as a natural biological control. In the Brazilian Amazon we sampled dung beetles, fly larvae and adults; and recorded the rate of dung removal by dung beetles across a gradient of land-use intensity from primary forest, secondary forest, agroforestry, agriculture to pasture. Our results provide evidence that land-use intensification results in a reduction of the richness, abundance and biomass of dung beetles, and this in turn results in lower rates of dung removal in the most simplified systems. We found no significant differences in the abundance of fly larvae between the different systems of land use. However, the number of adult flies differed significantly between land-use systems, presenting higher abundance in those sites with greater intensity of use (pasture and agriculture) and a lower abundance of adult flies in forested systems (primary and secondary forests, and agroforestry). Information-theoretic model selection based on AICc revealed strong support for the influence of land-use systems, dung removal rates and dung beetle abundance, biomass and richness on adult dung-fly abundance. Our results also reveal that dung beetles are not solely responsible for fly control and that other factors linked to land use are influencing the populations of these detritus-feeding insects. [ABSTRACT FROM AUTHOR]

The nature and scale of pre-Columbian land use and the consequences of the 1492 "Columbian Encounter" (CE) on Amazonia are among the more debated topics in New World archaeology and paleoecology. However, pre-Columbian human impact in Amazonian savannas remains poorly understood. Most paleoecological studies have been conducted in neotropical forest contexts. Of studies done in Amazonian savannas, none has the temporal resolution needed to detect changes induced by either climate or humans before and after A.D. 1492, and only a few closely integrate paleoecological and archaeological data. We report a highresolution 2,150-y paleoecological record from a French Guianan coastal savanna that forces reconsideration of how pre-Columbian savanna peoples practiced raised-field agriculture and how the CE impacted these societies and environments. Our combined pollen, phytolith, and charcoal analyses reveal unexpectedly low levels of biomass burning associated with pre-A.O. 1492 savanna raised-field agriculture and a sharp increase in fires following the arrival of Europeans. We show that pre-Columbian raised-field farmers limited burning to improve agricultural production, contrasting with extensive use of fire in pre-Columbian tropical forest and Central American savanna environments, as well as in present-day savannas. The charcoal record indicates that extensive fires in the seasonally flooded savannas of French Guiana are a post-Columbian phenomenon, postdating the collapse of indigenous populations. The discovery that pre-Columbian farmers practiced fire-free savanna management calls into question the widely held assumption that pre-Columbian Amazonian farmers pervasively used fire to manage and alter ecosystems and offers fresh perspectives on an emerging alternative approach to savanna land use and conservation that can help reduce carbon emissions. [ABSTRACT FROM AUTHOR]

Copyright of Annals of the Association of American Geographers is the property of Taylor & Francis Ltd 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.)

Study of the spatial patterns of land use and forest resource exploitation by a Yanomami community in northern Amazonia (Brazil) combining high-resolution satellite imagery and global positioning system survey data with ethnogeographic fieldwork shows that its natural-resource use is configured in terms of "reticular space" rather than a set of discrete concentric exploitation "zones." This model of reticular space has general relevance for the Yanomami and other Amazonian indigenous groups. The research reported demonstrates the value of a multidisciplinary methodology for gathering data on ethnogeographic practices and knowledge that are essential for the appropriate demarcation of indigenous protected areas and the long-term sustainable management of their environment in the Amazon and other tropical-forest environments. [ABSTRACT FROM AUTHOR]

This article addresses deforestation processes in the Amazon basin, using regression analysis to assess the impact of household structure and economic circumstances on land use decisions made by colonist farmers in the forest frontiers of Brazil. Unlike many previous regression-based studies, the methodology implemented analyzes behavior at the level of the individual property, using both survey data and information derived from the classification of remotely sensed imagery. The regressions correct for endogenous relationships between key variables and spatial autocorrelation, as necessary. Variables used in the analysis are specified, in part, by a theoretical development integrating the Chayanovian concept of the peasant household with spatial considerations stemming from von Thünen. Results from the empirical model indicate that demographic characteristics of households, as well as market factors, affect deforestation in the Amazon basin associated with colonists. Therefore, statistical results from studies that do not include household-scale information may be subject to error. From a policy perspective, the results suggest that environmental policies in the Amazon based on market incentives to small farmers may not be as effective as hoped, given the importance of household factors in catalyzing the demand for land. The article concludes by noting that household decisions regarding land use and deforestation are not independent of broader social circumstances, and that a full understanding of Amazonian deforestation will require insight into why poor families find it necessary to settle the frontier in the first place. [ABSTRACT FROM AUTHOR]

Wetter areas of the Amazon basin exhibit lower rates of agricultural conversion. Previous analyses, using relatively aggregate data on land cover, have been unable to determine the extent to which this reflects limited access versus unfavorable agroclimatic conditions. This article uses census-tract level data for the Brazilian Amazon to relate forest conversion and pasture productivity to precipitation, soil quality, infrastructure and market access, proximity to past conversion, and protection status. The probability that land is used for agriculture or intensively stocked with cattle declines markedly with increasing rainfall, other things equal. [ABSTRACT FROM AUTHOR]

Background: Brazilian Amazon forests contain a large stock of carbon that could be released into the atmosphere as a result of land use and cover change. To quantify the carbon stocks, Brazil has forest inventory plots from different sources, but they are unstandardized and not always available to the scientific community. Considering the Brazilian Amazon extension, the use of remote sensing, combined with forest inventory plots, is one of the best options to estimate forest aboveground biomass (AGB). Nevertheless, the combination of limited forest inventory data and different remote sensing products has resulted in significant differences in the spatial distribution of AGB estimates. This study evaluates the spatial coverage of AGB data (forest inventory plots, AGB maps and remote sensing products) in undisturbed forests in the Brazilian Amazon. Additionally, we analyze the interconnection between these data and AGB stakeholders producing the information. Specifically, we provide the first benchmark of the existing field plots in terms of their size, frequency, and spatial distribution. Results: We synthesized the coverage of forest inventory plots, AGB maps and airborne light detection and ranging (LiDAR) transects of the Brazilian Amazon. Although several extensive forest inventories have been implemented, these AGB data cover a small fraction of this region (e.g., central Amazon remains largely uncovered). Although the use of new technology such as airborne LiDAR cover a significant extension of AGB surveys, these data and forest plots represent only 1% of the entire forest area of the Brazilian Amazon. Conclusions: Considering that several institutions involved in forest inventories of the Brazilian Amazon have different goals, protocols, and time frames for forest surveys, forest inventory data of the Brazilian Amazon remain unstandardized. Research funding agencies have a very important role in establishing a clear sharing policy to make data free and open as well as in harmonizing the collection procedure. Nevertheless, the use of old and new forest inventory plots combined with airborne LiDAR data and satellite images will likely reduce the uncertainty of the AGB distribution of the Brazilian Amazon. [ABSTRACT FROM AUTHOR]