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1.
Indigenous peoples have been using fire in the cerrado (savannas) of Brazil as a form of management for thousands of years, yet we have little information on why, when and how these fire practices take place. The aim of this paper was to explore the traditional use of fire as a management tool by the Krahô indigenous group living in the north-eastern region of Tocantíns state, Brazil. The results indicate that the Krahô burn for a variety of reasons throughout the dry season, thereby producing a mosaic of burned and unburned patches in the landscape. The paper discusses this burning regime in the context of contemporary issues regarding fire management, and in the face of changing perceptions to fire by the Krahô themselves.  相似文献   

2.
Shifting cultivation practiced by indigenous peoples living at low population densities in tropical forests has often been described as sustainable and compatible with conservation. However, shifting cultivation at increasing population densities has historically been, and still is, a main cause of deforestation worldwide. As many indigenous peoples in tropical forests currently experience rapid demographic growth, this raises the question to what extent their agricultural activities actually contribute to deforestation. This paper examines land use change in an indigenous community in the Ecuadorian Amazon which is only loosely connected to the market economy, and where agriculture is almost exclusively subsistence oriented. During the last seven decades, people have increasingly begun to clear fallows instead of old-growth forest to farm. Although the population was growing at an estimated 1.6% per year, the expansion of the area of land used for agriculture was only 0.4% per year, corresponding to an annual deforestation rate of only 0.015%. Whereas these changes may seem negligible in terms of deforestation, they do cause hardships to the local people, because of increasing walking distance to old-growth forest, and problems with weeds, pests, and decreasing soil productivity when farming after reclearing fallows.  相似文献   

3.
Abstract Fire is an important ecological factor in Cerrado vegetation of central Brazil, and in other savanna ecosystems. The effect of fire on the abundance of some Xenarthran mammal species Priodontes maximus Kerr, 1792 (giant armadillo), Euphractus sexcinctus Linnaeus, 1758 (yellow armadillo) and Myrmecophaga tridactyla Linnaeus, 1758 (giant anteater)) was studied at Reserva Xavante do Rio das Mortes, a 329 000 ha Xavante Indian reserve in the Cerrado of Mato Grosso, Brazil. Track counts were used to compare the abundance of these mammals along seven burned and seven unburned transects, on seven occasions between August 1995 and August 1996. The number of tracks in burned and unburned areas did not differ. Xenarthrans probably use burned areas to obtain food resources, basically termites and ants. Xavante traditional fire hunts may reduce fuel accumulation and function as a mechanism to prevent more destructive fires. Fire management at Reserva Xavante is recommended because the burning system of Brazilian farmers is already influencing the Xavante community. Xavante traditional knowledge about fire could be an important instrument for this management.  相似文献   

4.
Nelson A  Chomitz KM 《PloS one》2011,6(8):e22722
Protected areas (PAs) cover a quarter of the tropical forest estate. Yet there is debate over the effectiveness of PAs in reducing deforestation, especially when local people have rights to use the forest. A key analytic problem is the likely placement of PAs on marginal lands with low pressure for deforestation, biasing comparisons between protected and unprotected areas. Using matching techniques to control for this bias, this paper analyzes the global tropical forest biome using forest fires as a high resolution proxy for deforestation; disaggregates impacts by remoteness, a proxy for deforestation pressure; and compares strictly protected vs. multiple use PAs vs indigenous areas. Fire activity was overlaid on a 1 km map of tropical forest extent in 2000; land use change was inferred for any point experiencing one or more fires. Sampled points in pre-2000 PAs were matched with randomly selected never-protected points in the same country. Matching criteria included distance to road network, distance to major cities, elevation and slope, and rainfall. In Latin America and Asia, strict PAs substantially reduced fire incidence, but multi-use PAs were even more effective. In Latin America, where there is data on indigenous areas, these areas reduce forest fire incidence by 16 percentage points, over two and a half times as much as naïve (unmatched) comparison with unprotected areas would suggest. In Africa, more recently established strict PAs appear to be effective, but multi-use tropical forest protected areas yield few sample points, and their impacts are not robustly estimated. These results suggest that forest protection can contribute both to biodiversity conservation and CO2 mitigation goals, with particular relevance to the REDD agenda. Encouragingly, indigenous areas and multi-use protected areas can help to accomplish these goals, suggesting some compatibility between global environmental goals and support for local livelihoods.  相似文献   

5.
Conservation attention to indigenous hunting with fire in the cerrado largely focuses on sustainability as construed in scientific terms rather than according to indigenous points of view. Towards the goal of reframing the debate in terms more congruent with indigenous perspectives, I address how the Xavante (A’uw?) view ritualized and collective hunting, including hunting with fire, as indispensable means of acquiring gifts by which to celebrate important events, express feelings of respect and gratitude towards others, promote positive social values among male youth, and maintain the group’s ethnic identity. In particular, ritualized exchanges of game meat are necessary and culturally appropriate means of expressing esteem for others at some of life’s most important moments. For the Xavante, the social imperative to give and receive gifts of meat during weddings and initiation ceremonies motivates efforts to maintain the collective hunting with fire tradition in a manner that ensures its long term environmental viability.  相似文献   

6.
Fire-driven deforestation is the major source of carbon emissions from Amazonia. Recent expansion of mechanized agriculture in forested regions of Amazonia has increased the average size of deforested areas, but related changes in fire dynamics remain poorly characterized. We estimated the contribution of fires from the deforestation process to total fire activity based on the local frequency of active fire detections from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors. High-confidence fire detections at the same ground location on 2 or more days per year are most common in areas of active deforestation, where trunks, branches, and stumps can be piled and burned many times before woody fuels are depleted. Across Amazonia, high-frequency fires typical of deforestation accounted for more than 40% of the MODIS fire detections during 2003–2007. Active deforestation frontiers in Bolivia and the Brazilian states of Mato Grosso, Pará, and Rondônia contributed 84% of these high-frequency fires during this period. Among deforested areas, the frequency and timing of fire activity vary according to postclearing land use. Fire usage for expansion of mechanized crop production in Mato Grosso is more intense and more evenly distributed throughout the dry season than forest clearing for cattle ranching (4.6 vs. 1.7 fire days per deforested area, respectively), even for clearings >200 ha in size. Fires for deforestation may continue for several years, increasing the combustion completeness of cropland deforestation to nearly 100% and pasture deforestation to 50–90% over 1–3-year timescales typical of forest conversion. Our results demonstrate that there is no uniform relation between satellite-based fire detections and carbon emissions. Improved understanding of deforestation carbon losses in Amazonia will require models that capture interannual variation in the deforested area that contributes to fire activity and variable combustion completeness of individual clearings as a function of fire frequency or other evidence of postclearing land use.  相似文献   

7.
Covering almost a quarter of Brazil, the Cerrado is the world’s most biologically rich tropical savanna. Fire is an integral part of the Cerrado but current land use and agricultural practices have been changing fire regimes, with undesirable consequences for the preservation of biodiversity. In this study, fire frequency and fire return intervals were modelled over a 12-year time series (1997–2008) for the Jalapão State Park, a protected area in the north of the Cerrado, based on burned area maps derived from Landsat imagery. Burned areas were classified using object based image analysis. Fire data were modelled with the discrete lognormal model and the estimated parameters were used to calculate fire interval, fire survival and hazard of burning distributions, for seven major land cover types. Over the study period, an area equivalent to four times the size of Jalapão State Park burned and the mean annual area burned was 34%. Median fire intervals were generally short, ranging from three to six years. Shrub savannas had the shortest fire intervals, and dense woodlands the longest. Because fires in the Cerrado are strongly responsive to fuel age in the first three to four years following a fire, early dry season patch mosaic burning may be used to reduce the extent of area burned and the severity of fire effects.  相似文献   

8.
1. In sub‐Saharan Africa, tropical forests are increasingly threatened by accelerating rates of forest conversion and degradation. In East Africa, the larger tracts of intact rainforest lie largely in protected areas surrounded by converted landscape. Thus, there is critical need to understand the functional links between large‐scale land use and changes in river conditions, and the implications of park boundaries on catchment integrity. 2. The objective of this study was to use the mosaic of heavily converted land and pristine forest created by the protection of the high‐altitude rainforest in Bwindi Impenetrable National Park, Uganda to explore effects of deforestation on aquatic systems and the value of forest in buffering effects of adjacent land conversion. A set of 16 sites was selected over four drainages to include four categories of deforestation: agricultural land, deforested upstream (of the park boundary), forest edge (park boundary) and forest. We predicted that forest buffer (downstream or on the edge) would moderate effects of deforestation. To address this prediction, we quantified relationships between disturbance level and both physicochemical characters and traits of the macroinvertebrate assemblages during six sampling periods (February 2003 and June 2004). 3. Results of both principal components analysis and cluster analyses indicated differences in limnological variables among deforestation categories. PC1 described a gradient from deforested sites with poor water quality to pristine forested sites with relatively good water quality. Agricultural sites and deforested upstream sites generally had the highest turbidity, total dissolved solids (TDS), and conductivity values and low transparency values. Forest sites and boundary site groups generally exhibited low turbidity, TDS, and conductivity values and high water transparency values. Sites also clustered according to deforestation categories; forest and forested edge sites formed a cluster independent of both agricultural land and deforested‐upstream. 4. Water transparency, water temperature, and pH were the most important factors predicting benthic macroinvertebrate assemblages. Sensitive invertebrate families of Trichoptera, Ephemeroptera, Plecoptera, and Odonata dominated forested sites with high water transparency, low water temperature, and low pH while the tolerant families of Ephemeroptera, Diptera, Hemiptera, and Coleoptera were abundant in agriculturally impacted sites with low water transparency, high water temperature, and high pH. 5. This study provides support for the importance of riparian buffers in moderating effects of deforestation. Forest and forested edge sites were more similar in both limnological and macroinvertebrate assemblage structure than sites within or downstream from agricultural lands. If the protected area cannot encompass the catchment, the use of rivers as park boundaries may help to maintain the biological integrity of the rivers by buffering one side of the watercourse.  相似文献   

9.
During the past three decades, mines have increased in number at the same time that indigenous populations have grown in size and acquired more land. The intersection of these two trends suggests that, increasingly, mining companies have tried to exploit mineral deposits on lands populated and controlled by indigenous peoples. These ventures touched off conflicts between organized indigenous peoples and state supported miners. The copper mining controversy in the Ecuadorian Amazon exemplifies this pattern. Legacies from earlier mestizo land invasions in the form of active NGOs and an extensive land base made Shuar resistance to the mines much more likely. Increasingly assertive national political leaders, pursuing an extractive imperative, reinforced the miners’ efforts to extract copper from deposits near Shuar settlements. To reduce the probability of violent conflict between these parties, indigenous people should have a seat at the table when negotiations between the mining companies and the state occur.  相似文献   

10.
The impact of fire use and hazard in frontier settlement is a critical environmental concern that has been historically overshadowed by deforestation issues- and thus underexamined at local and regional scales by social scientists. Consequently, conceptual frameworks of LUCC change consider fire use as an outcome of land use decisions and neglect the capacity of burning choices to influence these decisions and subsequent land cover change. This paper examines the relationship of settlement, land use, and fire use. It considers recent LUCC frameworks, and then uses household surveys on fire use practices to discuss how the study of fire use can contribute to understanding frontier landscape change. Planting decisions, settlement history, location desires, and burning logistics work in combination to influence burning choices and thus LUCC.  相似文献   

11.
Tropical and subtropical dry woodlands are rich in biodiversity and carbon. Yet, many of these woodlands are under high deforestation pressure and remain weakly protected. Here, we assessed how deforestation dynamics relate to areas of woodland protection and to conservation priorities across the world's tropical dry woodlands. Specifically, we characterized different types of deforestation frontier from 2000 to 2020 and compared them to protected areas (PAs), Indigenous Peoples' lands and conservation areas for biodiversity, carbon and water. We found that global conservation priorities were always overrepresented in tropical dry woodlands compared to the rest of the globe (between 4% and 96% more than expected, depending on the type of conservation priority). Moreover, about 41% of all dry woodlands were characterized as deforestation frontiers, and these frontiers have been falling disproportionately in areas with important regional (i.e. tropical dry woodland) conservation assets. While deforestation frontiers were identified within all tropical dry woodland classes of woodland protection, they were lower than the average within protected areas coinciding with Indigenous Peoples' lands (23%), and within other PAs (28%). However, within PAs, deforestation frontiers have also been disproportionately affecting regional conservation assets. Many emerging deforestation frontiers were identified outside but close to PAs, highlighting a growing threat that the conserved areas of dry woodland will become isolated. Understanding how deforestation frontiers coincide with major types of current woodland protection can help target context-specific conservation policies and interventions to tropical dry woodland conservation assets (e.g. PAs in which deforestation is rampant require stronger enforcement, inactive deforestation frontiers could benefit from restoration). Our analyses also identify recurring patterns that can be used to test the transferability of governance approaches and promote learning across social–ecological contexts.  相似文献   

12.
Professional and popular publications have increasingly depicted native peoples of Amazonia as “natural” conservationists or as people with an innate “conservation ethic.” A few classic examples are cited repeatedly to advance this argument with the result that these cases tend to be generalized to all indigenous peoples. This paper explores the premise that many of these systems of resource conservation come from areas of Amazonia where human survival depends on careful management of the subsistence base and not from a culturally imbedded “conservation ethic.” Where resource constraints do not pertain, as in the case of the Yuquí of lowland Bolivia, such patterns are unknown. Finally, the negative consequences of portraying all native peoples as natural conservationists is having some negative consequences in terms of current struggles to obtain indigenous land rights.  相似文献   

13.
Interactions of indigenous peoples with the surrounding non-indigenous society are often the main sources of social and environmental changes in indigenous lands. In the case of the Suruí in Brazilian Amazonia’s “arc of deforestation,” these influences are leading to deforestation and logging that threaten both the forest and the sustainability of the group’s productive systems. The Suruí tribal leadership has initiated a proposal for an economic alternative based on Reducing Emissions from Deforestation and Degradation (REDD). This has become a key case in global discussions on indigenous participation in REDD. The realism of the baseline scenario that serves as a reference for determining the amount of deforestation and emissions avoided by the proposed project is critical to assuring the reality of the carbon benefits claimed. Here we examine the SIMSURUI model, its input parameters and the implications of the Suruí Forest Carbon Project for indigenous participation in climate mitigation efforts.  相似文献   

14.
Recent research on the ecology of fire has challenged the view that the use of fire by indigenous peoples is detrimental to ecosystems and wildlife in protected areas. However, in Canaima National Park and World Heritage Site in southeastern Venezuela, since 1981 managers have employed a costly fire control program to eliminate savanna burning by the Pemon indigenous people. Here I present the results of the first study on Pemon perspectives of fire management in the park. I show that savanna burning is an important tool in indigenous land management and plays a key role in preventing large catastrophic fires. Pemon knowledge of fire also raises questions about conventional interpretations of environmental change in the park. Lastly, I recommend a fire management policy that seeks to integrate local ecological knowledge. This will require: (a) greater openness from scientists and resource managers to understanding Pemon rationale for the use of fire, (b) clarification among the Pemon themselves of their own views of fire, and (c) research partnerships among scientists, resource managers and the Pemon in order to encourage understanding of Pemon ecological knowledge of fire, and to assess its true impact in the Canaima National Park.  相似文献   

15.
The social impact of the mahogany trade on the indigenous peoples of Brazil is described. Emphasis is placed on the violence directed against Indians and the consequences of the destruction of their environment which results from the trade. Also mentioned are the judicial issues regarding the illegal extraction of mahogany from protected areas and several of the court cases against logging companies. A moratorium on mahogany logging in Brazil is advocated as is the right of indigenous peoples to control their lands and resources as the way to conserve their environment.  相似文献   

16.
Fire is a natural disturbance in savannas, and defines vegetation physiognomy and structure, often influencing species diversity. Fire activity is determined by a wide range of factors, including long and short term climatic conditions, climate seasonality, wind speed and direction, topography, and fuel biomass. In Brazil, fire shapes the structure and composition of cerrado savannas, and the impact of fire on vegetation dynamics is well explored, but the drivers of variation in fire disturbance across landscapes and over time are still poorly understood. We reconstructed 31 years of fire occurrence history in the Serra do Cipó region, a highly-diverse cerrado landscape, located in the southern portion of the Espinhaço mountain range, state of Minas Gerais, Southeastern Brazil. We mapped burn scars using a time series of Landsat satellite images from 1984 to 2014. Our questions were 1) How does fire occurrence vary in time and space across the Serra do Cipó cerrado landscape? 2) Which climatic drivers may explain the spatial and inter-annual variation in fire occurrence on this landscape? 3) Is fire occurrence in this cerrado landscape moisture-limited or fuel-limited? We evaluated the inter-annual variation and distribution of burned areas, and used linear models to explain this variation in terms of rainfall amount (determinant of fuel load production), seasonal rainfall distribution (determinant of dry fuel availability), abnormality of precipitation (Standardized Precipitation Index – SPI), and vegetation type (Enhanced Vegetation Index – EVI). Contrary to our expectations, annual rainfall volume was weakly and negatively correlated with burned area, and the strongest predictor of burned area was drought during the ignition season. The length of the dry season and the distribution of rain along the season determined ignition probability, increasing fire occurrence during the driest periods. We conclude that the mountain cerrado vegetation at Serra do Cipó has a moisture-dependent fire regime, in contrast to the fuel-dependent fire regimes described for African savannas. These findings imply that savannas at different continents may have different recovery and resilience capabilities when subjected to changes in the fire regime, caused by direct anthropogenic activities or indirectly through climatic changes. The possible effects of these changes on cerrado landscapes are still unknown, and future studies should investigate if currently observed fire regimes have positive or negative impacts on vegetation diversity, recovery, resilience and phenology, thus helping managers to include fire management as conservation measure.  相似文献   

17.
Tropical forests are diminishing in extent due primarily to the rapid expansion of agriculture, but the future magnitude and geographical distribution of future tropical deforestation is uncertain. Here, we introduce a dynamic and spatially-explicit model of deforestation that predicts the potential magnitude and spatial pattern of Amazon deforestation. Our model differs from previous models in three ways: (1) it is probabilistic and quantifies uncertainty around predictions and parameters; (2) the overall deforestation rate emerges “bottom up”, as the sum of local-scale deforestation driven by local processes; and (3) deforestation is contagious, such that local deforestation rate increases through time if adjacent locations are deforested. For the scenarios evaluated–pre- and post-PPCDAM (“Plano de Ação para Proteção e Controle do Desmatamento na Amazônia”)–the parameter estimates confirmed that forests near roads and already deforested areas are significantly more likely to be deforested in the near future and less likely in protected areas. Validation tests showed that our model correctly predicted the magnitude and spatial pattern of deforestation that accumulates over time, but that there is very high uncertainty surrounding the exact sequence in which pixels are deforested. The model predicts that under pre-PPCDAM (assuming no change in parameter values due to, for example, changes in government policy), annual deforestation rates would halve between 2050 compared to 2002, although this partly reflects reliance on a static map of the road network. Consistent with other models, under the pre-PPCDAM scenario, states in the south and east of the Brazilian Amazon have a high predicted probability of losing nearly all forest outside of protected areas by 2050. This pattern is less strong in the post-PPCDAM scenario. Contagious spread along roads and through areas lacking formal protection could allow deforestation to reach the core, which is currently experiencing low deforestation rates due to its isolation.  相似文献   

18.
Tropical deforestation is the major contemporary threat to global biodiversity, because a diminishing extent of tropical forests supports the majority of the Earth's biodiversity. Forest clearing is often spatially concentrated in regions where human land use pressures, either planned or unplanned, increase the likelihood of deforestation. However, it is not a random process, but often moves in waves originating from settled areas. We investigate the spatial dynamics of land cover change in a tropical deforestation hotspot in the Colombian Amazon. We apply a forest cover zoning approach which permitted: calculation of colonization speed; comparative spatial analysis of patterns of deforestation and regeneration; analysis of spatial patterns of mature and recently regenerated forests; and the identification of local‐level hotspots experiencing the fastest deforestation or regeneration. The colonization frontline moved at an average of 0.84 km yr?1 from 1989 to 2002, resulting in the clearing of 3400 ha yr?1 of forests beyond the 90% forest cover line. The dynamics of forest clearing varied across the colonization front according to the amount of forest in the landscape, but was spatially concentrated in well‐defined ‘local hotspots’ of deforestation and forest regeneration. Behind the deforestation front, the transformed landscape mosaic is composed of cropping and grazing lands interspersed with mature forest fragments and patches of recently regenerated forests. We discuss the implications of the patterns of forest loss and fragmentation for biodiversity conservation within a framework of dynamic conservation planning.  相似文献   

19.
Among the remaining tropical forests of lowland Latin America, many are inhabited by indigenous peoples, and the sustainability of their land uses is a point of heated debate in the conservation community. Numerous small-scale studies have documented changes in indigenous land use in individual communities in the context of expanding frontier settlements and markets, but few studies have included larger populations or multiple ethnic groups. In this paper we use data from a regional-scale survey of five indigenous populations in the Northern Ecuadorian Amazon to describe their agricultural land use practices and investigate the factors that affect those practices. We find the areas cultivated by indigenous households to be small compared to those of nearby mestizo colonists, but a large proportion of indigenous cultivated area is in commercial land uses. We also construct multilevel statistical models to investigate the household and community-level factors that affect indigenous land use. The results reveal significant influences on cultivated area from contextual factors such as access to markets, oil company activities, and the land tenure regime, as well as from household characteristics such as demographic composition, participation in alternative livelihood activities, and human, social and physical capitals. Overall the results are most consistent with market integration as an underlying driver of land use change in indigenous territories of the study area.
Clark L. GrayEmail:
  相似文献   

20.
The Caatinga is a botanically unique semi‐arid ecosystem in northeast Brazil whose vegetation is adapted to the periodic droughts that characterize this region. However, recent extreme droughts events caused by anthropogenic climate change have challenged its ecological resilience. Here, we evaluate how deforestation and protection status affect the response of the Caatinga vegetation to drought. Specifically, we compared vegetation responses to drought in natural and deforested areas as well as inside and outside protected areas, using a time‐series of satellite‐derived Normalized Difference Vegetation Index (NDVI) and climatic data for 2008–2013. We observed a strong effect of deforestation and land protection on overall vegetation productivity and in productivity dynamics in response to precipitation. Overall, deforested areas had significantly lower NDVI and delayed greening in response to precipitation. By contrast, strictly protected areas had higher productivity and considerable resilience to low levels of precipitation, when compared to sustainable use or unprotected areas. These results highlight the importance of protected areas in protecting ecosystem processes and native vegetation in the Caatinga against the negative effects of climate change and deforestation. Given the extremely small area of the Caatinga currently under strict protection, the creation of new conservation areas must be a priority to ensure the sustainability of ecological processes and to avoid further desertification.  相似文献   

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