Conversion Of Cerrado Research Articles

The conversion of native savannah into pasturelands does not affect exclusively species diversity: Effects on physiological condition of a highly abundant dung beetle species.

Dung beetles are efficient indicators to obtain responses regarding the effects of land use change on biodiversity. Although the biological consequences of Cerrado conversion into pasture have been observed at the assemblage scale, there are no cues regarding the effects of tropical savanna conversion into pasture on physiological condition of dung beetle individuals. In this study, we evaluated whether native and non-native habitats in Cerrado affect the physiological condition and body traits of males and females of Phanaeus palaeno. The individuals were collected from a Cerrado fragment (sensu stricto) and an exotic pasture (Urochloa spp.). Physiological condition was assessed through the estimation of individuals' dry body mass, fat mass, and muscle mass. Body traits were estimated through individual body size and males' horn length. We did not find differences between dung beetle morphological traits between Cerrado and pastures. However, individuals collected in exotic pastures had lower dry mass and fat mass, but higher muscle mass, than in conserved Cerrado. Understanding how the land use change affects individuals' body condition is essential to maintain abundant and healthy populations of dung beetles in human-modified landscapes. Although the estimation of physiological condition is logistically more complex than species body traits, future studies aiming to present complex and finer ecological responses of dung beetles should incorporate physiological data to their approaches.

The role of natural and anthropic factors in the variability of soil loss in the state of Goiás between 1985 and 2018

Soil loss depends on natural and anthropic factors with high spatial and temporal variability, and can be inferred by predictive models such as the Revised Universal Soil Loss Equation (RUSLE). In this sense, the objective of this work is to analyze the spatio-temporal distribution and variation of soil losses in the state of Goiás for the years 1985, 2000 and 2018, based on the application of RUSLE and using the drainage basin as a multiscale unit of analysis. The results generally show that there has beenan increase in the average loss of soils in the state between the observed years with the average in 1985 being 2.4 ton.ha-1.year-1, growing to 10.8 ton.ha-1.year-1 in 2000, and 11.56 ton.ha-1.year-1 in 2018. The hydrographic regions of Tocantins and Paraná presented the highest losses. In addition to the general control of the Cerrado conversion expansion, the state of Goiás presents two spatial soil loss patterns; one in which the control of natural factors predominates, being linked to morphogenetic aspects with a strong influence of the topographic factor; and the other being rain erosivity, spatialized in areas such as the “front” of Cuesta Caiapó, Serra Dourada and Serra dos Pireneus. When associated, these two factors define sensitive areas with the highest soil losses in the state of Goiás.

Cerrado vegetation conversion into exotic pastures negatively impacts flower chafer beetle assemblages in the west-Central Brazil

The native vegetation conversion into exotic pastures has been some of the most common land changes in the Brazilian Cerrado, causing biodiversity declines. However, our understanding of how biodiversity communities are responding to this activity is still limited for many biological groups. In this study, we evaluated the effects of Cerrado vegetation conversion into exotic pastures on flower chafer beetle assemblages. We sampled flower chafer beetles using aerial fruit baited-traps, every two weeks from October to December 2013, in five sites of Brazilian Cerrado (sensu stricto) and in five sites of exotic pastures (Urochloa spp.) in Aquidauana, Mato Grosso do Sul, Brazil. A total 311 individuals from three genera and seven species were sampled. The species richness and abundance of flower chafer beetles were higher in Cerrado remnants. Species composition was similar between Cerrado remnants and exotic pastures in position, but was different in dispersion. Our results demonstrate that Cerrado conversion into exotic pastures reduces the abundance and species richness of flower chafer beetles, causing the alteration in species composition in terms of dispersion. Although these beetles can be ‘guests’ in exotic pasture sites, using them as ecological corridors, exotic pastures establishment negatively impacts flower chafer beetle assemblages in the Brazilian Cerrado.

Isotopic variations of carbon and nitrogen and their implications on the conversion of Cerrado vegetation into pasture

Conversions of natural vegetation into pasture can, in a short time, change the carbon stock and the natural abundance of δ13C in the soil. The objective of this study was to evaluate changes in carbon (C) and nitrogen (N) stocks, as well as in the natural abundance of δ13C and δ15N of Argissolo Vermelho distrófico (Acrisol), in an area of natural vegetation and planted pasture in the Cerrado region of Aquidauana (MS), Brazil. In order to do this, an area of pasture (PA), cultivated for 25 years with Urochloa brizantha, and an area of natural vegetation (NV) were evaluated. Soil samples were collected at intervals of 0.05 m up to 0.60 m depth, and physical attributes, C and N stocks (CSt and NSt) and isotopic variations of δ13C and δ15N of soil were determined. In the 0–0.05 m layer, the highest C and N stocks occurred in NV, 21.99 and 1.9 Mg ha-1, respectively. In the conversion to PA, 14.62 Mg ha-1 of CSt and 1.36 Mg ha-1 of NSt were lost in the 0–0.05 m layer. The area with PA had greater isotopic enrichment of δ13C in the layers of 0–0.05 and 0.05–0.10 m, with values of -18.3 and -17.4‰, respectively, while in the other layers the isotopic values decreased with the mixture between C of C3 and C4 plants. NV showed enrichment in the isotopic signals, in the layers from 0.25–0.30 m up to 0.40–0.45 m, with values between -21.74 and -21.54‰, respectively, which is characteristic of mixed vegetation of C3 and C4 plants. The values of δ15 N showed isotopic enrichment as depth increased, indicating greater mineralization of soil organic matter in both areas. The conversion of Cerrado into pasture and its consequent fragmentation causes negative impacts on the C and N sequestration and storage capacity, both in pasture and in natural vegetation.

Impact of the conversion of Brazilian woodland savanna (cerradão) to pasture and Eucalyptus plantations on soil nitrogen mineralization

The Brazilian savanna (Cerrado) has been extensively converted to croplands, pastures and forestry plantations, and the deforestation frontier continues expanding. Land conversion may cause critical changes in soil functioning, yet very little is still known about the impact of Cerrado conversion on nutrient cycling and soil fertility. Here, we addressed this knowledge gap by investigating the effects of the woodland cerrado (cerradão) conversion into pastures and Eucalyptus plantations on nitrogen availability and mineralization potential, considering a wide range of spatial and temporal variability due to soil depth, site conditions, and seasonal variation. For three sites in São Paulo state and each of the target land cover types, we assessed the total N and inorganic N (NH4-N and NO3-N) pools, potentially mineralizable nitrogen (PMN) and soil urease activity in the first 2 m of the soil profile. Cerrado conversion to either pastures or Eucalyptus plantations significantly reduced NH4-N, while NO3-N showed similar values in Cerrado and Eucalyptus and lower values in pastures. We found a consistent pattern of lower N mineralization in the uppermost soil layers associated to Cerrado conversion, with decreases in PMN rate and urease activity. The soil below 30 cm depth showed no relevant changes. Considering the first 30 cm of the soil profile, the reduction in the stocks of inorganic N (NH4-N + NO3-N) ranged from ~14% for the conversion to Eucalyptus to ∽20% for the conversion to pasture. The impact of land conversion on N cycling surpassed the influence of the spatial (between-site) and seasonal variation. Overall, the results indicate a decline in available N and overall soil fertility due to Cerrado conversion, which could further increase N limitation in the Cerrado region, increase fertilization needs for future exploitation, and compromise the recovery of Cerrado in case of land abandonment or restoration.

Soy expansion in Brazil's Cerrado

AbstractThe Cerrado biome is Brazil's breadbasket and a major provider of ecosystem services, though these dual roles are increasingly at odds, in part because there are few mechanisms to protect remaining vegetation from large‐scale agricultural expansion. We assessed Cerrado conversion to soy using over 580,000 property boundaries, covering 77% of the biome that is eligible for commercial land use, and using microwatersheds, to cover 100% of eligible areas. Soy expansion accounted for 22% of conversion during 2003–14. Only 15% of clearing exceeded restrictions on private properties under the Forest Code (FC). However, 51% of soy farms have violated the FC, five times the rate of other farms. As a leading cause of both Cerrado conversion and FC violations, the soy sector has environmental and economic incentives to shift production to already cleared land. We used suitability maps to identify potential pathways for soy expansion across both old and new cropland frontiers.

Effects of land-use change on chemical attributes of a Ferralsol in Brazilian Cerrado

The expansion of agriculture in the Brazilian Cerrado biome occurs at the expense of replacing native forest with pasture and/or crops. Negative environmental impacts, such as soil degradation, have been observed during this process. We aimed to evaluate the effect of different agricultural management systems on chemical attributes and soil organic matter fractions of a Ferralsol in an area of Cerrado, in the municipality of Hidrolândia, Goiás, Brazil. The following management systems were evaluated: (a) pasture (PAST), (b) no-tillage system (NT), organic cultivation (ORG) systems with different years of cultivation (2, 6, 8, and 10 years), and (c) a conventional management system (CS). Further, an area under native Cerrado forest (NF) was selected and used as a reference for steady state. Soil cores were collected at 0.0–0.10, 0.10–0.20, and 0.20–0.40 m depths. Macronutrients, total organic C (TOC), particulate organic C (POC), humic substances, and labile-C (Lab-C) were analyzed. The land-use change effect, driven by deforestation with subsequent pasture and/or crop, was evident by principal component (PC) analysis. In the 0.0–0.10 m soil layer, PC2 showed the isolation of NF from agricultural systems, whereas PC1 exhibited similar phenomena for the 0.10–0.20 and 0.20–0.40 m layers. In all cases, the agricultural systems showed weak correlation to TOC, POC, Lab-C and base saturation, suggesting loss of soil chemical fertility compared to NF. The ORG-8 area differed from other managed systems mainly due to high pH, P content, and base saturation. Soil cation exchange capacity was highly correlated to variables associated with soil organic matter, such as TOC, POC, and Lab-C. This result demonstrates that Cerrado soils are highly dependent on soil organic C dynamics. Conversion of Cerrado into agricultural land decreases soil chemical fertility. However, agroecosystems that reduce soil tillage and increase organic inputs, such as organic cultivation and no-tillage, seem to be suitable options for agricultural activity in Brazilian Cerrado.

Process-based modelling of the impacts of land use change on the water balance in the Cerrado Biome (Rio das Mortes, Brazil)

Since the 1980s, the state of Mato Grosso, Brazil, exhibits high rates of Cerrado conversion in favour of soybean expansion and cattle ranching. This conversion process becomes obvious in the upper Rio das Mortes macro-catchment. The objective of this study was to assess the influence of future land use changes on the discharge dynamics of the Rio das Mortes River. A single catchment approach was applied with the physically-based water balance simulation model WaSiM 8.5.0 (Schulla and jaSper 2007) to simulate land use scenarios. In Scenario 1, only small pasture sites (< 1 km²) were converted into the respective land use type surrounding them (i.e. cropland or Cerrado vegetation), whereas in Scenario 2 all pasture sites were converted into cropland and all Cerrado patches were then transformed into pastures. The WaSiM model was calibrated and validated based on discharge data measured at two gauging stations, achieving Nash-Sutcliffe coeffcients of 0.81 calibration) and 0.68 (validation). Main problems in modelling arise because of scarce spatial distributed data on subsurface parameter and vegetation parameter (Cerrado biome). Therefore, the use of the numerical groundwater model and manifold calibration runs were essential in this modelling approach to allow the simulation of the high levels of baseflow during the dry season and the transition from the dry to the wet season. The immediate rise of the baseflow in response to the increasing precipitation at beginning of the rainy season is a result of high soil hydraulic conductivity and groundwater recharge. These soil characteristics apparently persist on newly-created pasture and cropland sites, which still exhibit high ksat values after deforestation. Simulated evapotranspiration is comparable to literature values (Eddy flux measurements, MODIS-EVI calculation) and recently done paired micro-catchment studies in this catchment. The scenario analysis indicates that there are only small differences in runoff volume, which is directly related to the precipitation changes. In the scenario 2, groundwater recharge and base flow increase, whereas surface runoff does not. Therefore, the ongoing land use intensification with pasture conversion to cropland, remaining high infiltration and slight increase of evapotranspiration may not change runoff volume and discharge characteristics.

Soil, land use time, and sustainable intensification of agriculture in the Brazilian Cerrado region.

The Brazilian Cerrado area is in rapid decline because of the expansion of modern agriculture. In this study, we used extensive field data and a 30-year chronosequence of Landsat images (1980-2010) to assess the effects of time since conversion of Cerrado into agriculture upon soil chemical attributes and soybean/corn yield in the Alto do Rio Verde watershed. We determined the rates of vegetation conversion into agriculture, the agricultural land use time since conversion, and the temporal changes in topsoil (0-20cm soil depth) and subsurface (20-40cm) chemical attributes of the soils. In addition, we investigated possible associations between fertilization/over-fertilization and land use history detected from the satellites. The results showed that 61.8% of the native vegetation in the Alto do Rio Verde watershed was already converted into agriculture with 31% of soils being used in agriculture for more than 30years. While other fertilizers in cultivated soils (e.g., Ca+2, Mg+2, and P) have been compensated over time by soil management practices to keep crop yield high, large reductions in C org (38%) and N tot (29%) were observed in old cultivated areas. Furthermore, soybean and cornfields having more than 10years of farming presented higher values of P and Mg+2 than the ideal levels necessary for plant development. Therefore, increased risks of over-fertilization of the soils and environmental contamination with these macronutrients were associated with soybean and cornfields having more than 10years of farming, especially those with more than 30years of agricultural land use.

Understanding patterns of land-cover change in the Brazilian Cerrado from 2000 to 2015.

Clearing tropical vegetation impacts biodiversity, the provision of ecosystem services, and thus ultimately human welfare. We quantified changes in land cover from 2000 to 2015 across the Cerrado biome of northern Minas Gerais state, Brazil. We assessed the potential biophysical and socio-economic drivers of the loss of Cerrado, natural regeneration and net cover change at the municipality level. Further, we evaluated correlations between these land change variables and indicators of human welfare. We detected extensive land-cover changes in the study area, with the conversion of 23 446 km(2) and the natural regeneration of 13 926 km(2), resulting in a net loss of 9520 km(2) The annual net loss (-1.2% per year) of the cover of Cerrado is higher than that reported for the whole biome in similar periods. We argue that environmental and economic variables interact to underpin rates of conversion of Cerrado, most severely affecting more humid Cerrado lowlands. While rates of Cerrado regeneration are important for conservation strategies of the remaining biome, their integrity must be investigated given the likelihood of encroachment. Given the high frequency of land abandonment in tropical regions, secondary vegetation is fundamental to maintain biodiversity and ecosystem services. Finally, the impacts of Cerrado conversion on human welfare likely vary from local to regional scales, making it difficult to elaborate land-use policies based solely on socio-economic indicators.This article is part of the themed issue 'Tropical grassy biomes: linking ecology, human use and conservation'.

Dinâmica da matéria orgânica de um neossolo quartzarênico de cerrado convertido para cultivo em sucessão de soja e milheto

O uso e o manejo de Neossolos Quartzarênicos podem influenciar a matéria orgânica do solo (MOS), mas a magnitude dessas alterações ainda é pouco pesquisada nas condições de Cerrado. O objetivo deste trabalho foi estudar as variações que ocorrem na MOS em um Neossolo Quartzarênico, por consequência da conversão da vegetação original para o uso agrícola e cultivo sequencial de soja e milheto em sucessão. Em uma área de cultivo comercial em Alto Garças, MT, foram coletadas amostras de solo nas profundidades de 0-5, 0-10, 0-20 e 0-40 cm, em talhões que estavam sob sucessão soja-milheto durante 1, 2, 6, 8 e 10 anos e, como referência da vegetação original, amostras foram tomadas em área adjacente sob Cerrado nativo. Foram determinados os teores de carbono orgânico total (COT), carbono e nitrogênio total e o teor de carbono nas frações ácidos húmicos, ácidos fúlvicos e na matéria orgânica leve (MOL), além da relação isotópica do carbono na MOS. A conversão do Cerrado para cultivo agrícola elevou o teor de COT do solo, sobretudo em razão do aporte de MOL e fragmentos de carvão. O manejo desse solo com a sucessão soja-milheto, mesmo com o uso de gradagens pesadas, não causou reduções nos teores de COT, ao longo do tempo. Contudo, observou-se variação na distribuição do carbono nas diferentes frações da MOS ao longo do tempo de cultivo, indicando alterações significativas na qualidade da MOS. Notou-se aumento no percentual de carbono na forma de MOL e redução dos teores de carbono na forma de ácidos fúlvicos ao longo do tempo de cultivo, sugerindo a perda seletiva dos compostos mais solúveis. A relação isotópica do carbono do solo aumentou com o tempo de cultivo, indicando maior contribuição do carbono derivado do milheto para a manutenção dos teores de MOS. Os atributos da MOS relativos à camada de 0-20 cm foram mais sensíveis às variações em razão do tempo de cultivo do que os mesmos atributos avaliados nas demais camadas estudadas. As variáveis relacionadas ao fracionamento da MOS evidenciaram-se mais sensíveis às variações por causa do tempo de cultivo do que simplesmente do teor de COT do solo, apresentando o potencial de uso dessas variáveis como indicadores de qualidade do solo.

Modelling potential landscape sediment delivery due to projected soybean expansion: A scenario study of the Balsas sub-basin, Cerrado, Maranhão state, Brazil

In Brazil, agriculture expansion is taking place primarily in the Cerrado ecosystems. With the aim of supporting policy development and protecting the natural environment at relevant hotspots, a scenario study was conducted that concerned not only land-use change, but also the resulting effects on erosion and deposition. This coupled approach helped to evaluate potential landscape impacts of the land-use scenarios. In the study area, the Balsas sub-basin in Maranhão State, a model chain was used to model plausible future soybean expansion locations (CLUE-S model) and resulting sediment mobilization patterns (LAPSUS model) for a business-as-usual scenario. In the scenario, more erosion occurred in areas where the conversion of natural vegetation into soybean cultivation is likely to take place, but the generated sediments tended to accumulate mainly within the conversion areas, thus limiting the offsite effects of the increased erosion. These results indicated that when agricultural expansion is kept away from rivers, Cerrado conversion will have only a limited impact on the sediment loads of local rivers. Where land-use changes are most concentrated are coincident with areas where more new sediments are generated (higher erosion) and where more sediments are re-deposited.

Variações nos teores do C total e isotópico do solo após substituição do Cerrado em sistemas agrícolas no Triângulo Mineiro

Os solos do Cerrado sofrem impactos resultantes da substituição da vegetação original em sistemas agrícolas traduzidos na forma de desequilíbrios nos estoques e natureza do carbono. A região do Triângulo Mineiro vem sendo intensamente desmatada por ser uma área pioneira de expansão do agronegócio e apresenta sérios problemas relacionados à erosão do solo. Esta pesquisa teve como objetivo avaliar as mudanças na quantidade (Ctotal) na natureza (δ13C) do carbono do solo após conversão do cerrado denso em áreas com diferentes usos agrícolas (pastagem, soja e rotação soja/milho), manejos (sistemas convencionais e plantio direto). Os resultados mostraram que as mudanças nos valores relacionados ao uso e manejo são determinados também pelas características texturais dos solos formados pela alteração de litotipos distintos. Dentre os diferentes usos e manejo, o maior enriquecimento da taxa de carbono foi determinado na área com soja/milho no sistema de plantio direto em solo argiloso e o maior empobrecimento em pastagens não manejadas em solos desenvolvidos da alteração do arenito das Formações Adamantina e Marília. Estes estudos são úteis para serem usados como indicadores de qualidade para a conservação ambiental.

Access Regimes and Regional Land Change in the Brazilian Cerrado, 1972–2002

We examine how access regimes, defined by a set of interrelated institutions and organizations, facilitated the flow of production resources and benefits that resulted in patterns of land change in the Brazilian Cerrado. We analyzed remotely sensed data (Landsat MSS, TM, +ETM) for three time periods (1972/1973–1986, 1986–1992, 1992–2002) with qualitative and archival data for eastern Mato Grosso state. Overall we found that land privately colonized was cleared more rapidly and extensively than lands under no colonization scheme. We also identified significant spatial variability in Cerrado conversion within and outside colonization areas and variability of annual rates of Cerrado conversion during each period. We explain that farmers in the Cerrado engaged in land-leasing and production contracts and worked through cooperatives and firms to marshal resources, including credit, technology, and inputs, which, in turn, influenced land-use decisions and regional patterns of land-cover change. We conclude that a mesoscale analytical framework that examines how land managers access natural and productive resources provides useful insights to explain the processes that cause patterns of high-input agricultural expansion.

Conversion of cerrado into agricultural land in the south-western Amazon: carbon stocks and soil fertility

Land use change and land management practices can modify soil carbon (C) dynamics and soil fertility. This study evaluated the effect of tillage systems (no-tillage - NT and conventional tillage - CT) on soil C and nutrient stocks in an Oxisol from an Amazonian cerrado following land use change. The study also identified relationships between these stocks and other soil attributes. Carbon, P, K, Ca and Mg stocks, adjusted to the equivalent soil mass in the cerrado (CE), were higher under NT. After adoption of all but one of the NT treatments, C stocks were higher than they were in the other areas we considered. Correlations between C and nutrient stocks showed positive correlations with Ca and Mg under NT due to continuous liming, higher crop residue inputs and lack of soil disturbance, associated with positive correlations with cation exchange capacity (CEC), base saturation and pH. The positive correlation (r = 0.91, p &lt; 0.05) between C stocks and CEC in the CE indicates the important contribution of soil organic matter (SOM) to CEC in tropical soils, although the exchange sites are - under natural conditions - mainly occupied by H and Al. Phosphorus and K stocks showed positive correlations (0.81 and 0.82, respectively) with C stocks in the CE, indicating the direct relationship of P and K with SOM in natural ecosystems. The high spatial variability of P and K fertilizer application may be obscuring these soil nutrient stocks. In this study, the main source of P and K was fertilizer rather than SOM.

Carbon sequestration in agricultural soils in the Cerrado region of the Brazilian Amazon

The introduction of crop management practices after conversion of Amazon Cerrado into cropland influences soil C stocks and has direct and indirect consequences on greenhouse gases (GHG) emissions. The aim of this study was to quantify soil C sequestration, through the evaluation of the changes in C stocks, as well as the GHG fluxes (N 2O and CH 4) during the process of conversion of Cerrado into agricultural land in the southwestern Amazon region, comparing no-tillage (NT) and conventional tillage (CT) systems. We collected samples from soils and made gas flux measurements in July 2004 (the dry season) and in January 2005 (the wet season) at six areas: Cerrado, CT cultivated with rice for 1 year (1CT) and 2 years (2CT), and NT cultivated with soybean for 1 year (1NT), 2 years (2NT) and 3 years (3NT), in each case after a 2-year period of rice under CT. Soil samples were analyzed in both seasons for total organic C and bulk density. The soil C stocks, corrected for a mass of soil equivalent to the 0–30-cm layer under Cerrado, indicated that soils under NT had generally higher C storage compared to native Cerrado and CT soils. The annual C accumulation rate in the conversion of rice under CT into soybean under NT was 0.38 Mg ha −1 year −1. Although CO 2 emissions were not used in the C sequestration estimates to avoid double counting, we did include the fluxes of this gas in our discussion. In the wet season, CO 2 emissions were twice as high as in the dry season and the highest N 2O emissions occurred under the NT system. There were no CH 4 emissions to the atmosphere (negative fluxes) and there were no significant seasonal variations. When N 2O and CH 4 emissions in C-equivalent were subtracted (assuming that the measurements made on 4 days were representative of the whole year), the soil C sequestration rate of the conversion of rice under CT into soybean under NT was 0.23 Mg ha −1 year −1. Although there were positive soil C sequestration rates, our results do not present data regarding the full C balance in soil management changes in the Amazon Cerrado.

Stream‐valley systems of the Brazilian Cerrado: impact assessment and conservation scheme

1. The Cerrado, a seasonal savanna vegetation, is one of the largest biomes in the Neotropics. Conversion of Cerrado into agroecosystems has caused severe alterations in the species composition, functioning and habitat structure of streams and rivers. 2. As a case study for the Cerrado, the environmental quality of stream-valley systems was investigated in the catchment of the Tenente Amaral River near the city of Jaciara, Mato Grosso, Brazil. 3. Interpreting a Landsat-7 image of the area, and using a rapid assessment protocol with airborne and field observations, 481 first-order streams were identified in the catchment area (875.36 km2), equivalent to an average of 0.55 springs per square kilometre. The total stream density was 0.83 km km−2. 4. Only the uppermost headwater zones of the streams were unimpaired (8.5% of the stream channels). The largest part of the studied stream sectors were moderately (59.3%) or strongly (32.2%) impaired. 5. The greatest impact was caused by erosion. Sediments released by gully erosion alone were calculated as 2.6 × 106 m3 of sediments in the upper zone of one tributary of the Tenente Amaral River. The sediments had deleterious effects on fauna and flora. 6. The highly erosion-prone stream valleys in the Cerrado require full protection. In the transition area between agroecosystems and hillslopes, buffer zones consisting of a replanted interfluvial Cerrado tree vegetation and a vegetated buffer strip should be planted. Apart from erosion protection, these strips can provide valuable income for the farmers through selling non-wood products. 7. The legal situation providing the baseline for the protection of the Cerrado streams is reviewed, including the efforts of the Brazilian states and collaboration of UNESCO. 8. We suggest that it is possible to transfer this management strategy to similar biomes in the seasonal tropics provided that the tree species lists are carefully adapted to the regional flora. Copyright © 2006 John Wiley & Sons, Ltd.

Agricultural land-use change in Brazilian Amazônia between 1980 and 1995: Evidence from integrated satellite and census data

As cropland and pasture have replaced forest and cerrado in Brazilian Amazônia, concern has mounted over the effects of changing the biogeochemical and hydrological properties of one of the world's great storehouses of biomass and biodiversity. Although much recent effort has focused on the location, effects, and causes of deforestation and cerrado conversion, much less is known about the basin-wide spatial distribution and density of the land use following conversion for crops or pasture. In this paper, we use census and satellite records to develop maps of the distribution and abundance of major agricultural land uses across 4.5×10 8 ha of Brazilian Amazônia in 1980 and 1995. Results indicate an overall expansion of 7.0×10 6 ha in total agricultural area in Brazilian Amazônia between 1980 and 1995. The net change during this period is estimated for three different land-use types: croplands (an increase of 0.8×10 6 ha), natural pastures (a decrease of 8.4×10 6 ha), and planted pastures (an increase of 14.7×10 6 ha). These estimates, the first spatially explicit quantifications of agricultural land-use activities in 1980 and 1995 across Brazilian Amazônia, are shown to be consistent with the results of applying a land use change and secondary regrowth model to published deforestation rates for the period. The resulting time slices, presented for each land-use category at 5-min (∼9 km) spatial resolution, allow for the quantification of land-use changes in this region for biogeochemical, demographic and economic models. Several foci of agricultural change existed within Brazilian Amazônia during this period: in the state of Pará, cropland was lost and planted pasture increased markedly; in Mato Grosso, both cropland and planted pasture increased; in Rondônia, planted pasture replacing forest was the primary route to agricultural expansion.