Conversion Of Native Vegetation Research Articles

The challenge of commodity-centric governance in sacrifice frontiers: Evidence from the Brazilian Cerrado's soy sector

Conservation governance is increasingly globalized, particularly supply chain polices implemented by multinational corporations. However, the ways that local elite narratives and power networks influence the design and implementation of policies is poorly understood. We examine the role that local agribusiness narratives have on producers’ resistance to supply chain policies through the concept of the “sacrifice frontier”. We theorize sacrifice frontiers are regions where reinforcing perceptions that conversion of native vegetation has high economic potential and low conservation importance combine with rapid processes of wealth and power consolidation by agribusiness interests. We posit that these dimensions of a sacrifice frontier make rapid land use change and ongoing social and ecological harm especially probable as they reinforce constraints on sustainability governance. Here, we build on existing theories of environmental sacrifice through the case of the Cerrado biome, Brazil’s most active deforestation frontier. We argue that in the Cerrado, and other sacrifice frontiers like it, interventions that seek to reduce native vegetation loss cannot rely on supply-chain led policies, but instead need to foster more territorial multi-sectoral and multi-stakeholder discussions to alter the narrative of sociocultural and biodiversity sacrifice locally. We suggest this can be achieved by paying attention to local needs in a manner that is inclusive to all land users present within a targeted landscape.

Simulation of groundwater-flow dynamics in the U.S. Northern High Plains driven by multi-model estimates of surficial aquifer recharge

There is growing interest in incorporating higher-resolution groundwater modeling within the framework of large-scale land surface models (LSMs), including processes such as three-dimensional flow, variable soil saturation, and surface water/groundwater interactions. Conversely, complex groundwater models (e.g., the U.S. Geological Survey Groundwater-Flow Model, MODFLOW) often use simpler representations of land surface dynamics (e.g., surface vegetation, evapotranspiration, recharge) and may benefit from higher process fidelity and temporal resolutions in these inputs. This study investigates the potential of improving groundwater representation in LSMs and land surface dynamics in MODFLOW through forcing MODFLOW with recharge from LSMs. Groundwater simulations build on an existing and well-calibrated MODFLOW model of the U.S. Northern High Plains aquifer, a hydrologically complex basin under the dual impacts of conversion of native vegetation to intense irrigated agricultural fields and climate change. Simulated groundwater recharge from four different land models are used to drive MODFLOW groundwater simulations. Results show relatively large discrepancies between recharge estimates among simulations. Forcing MODFLOW using recharge simulated by some of the LSMs in place of a simple water balance model marginally improves MODFLOW groundwater simulation. Further, our results support the efficacy of coupling LSMs to a sophisticated groundwater model such as MODFLOW. The coupling results in notable improvements in matching the historical groundwater levels through reduction of the skewness coefficient in percent bias histogram (from 1.50 and 1.41 in original LSMs to 0.44 and 0.27, respectively, when MODFLOW is forced by groundwater recharge from LSMs) and reduction of bias. This modeling effort seeks to identify the best compromise between comprehensive land surface processes from global LSMs and advanced representation of groundwater from regional models.

Changes in Soil Organic Carbon Stocks Due to Land Use Changes in the Extended São Francisco River Basin

As the largest carbon reservoir in terrestrial ecosystems, soils play a critical role in food production, mitigation and adaption to climate change, and sustainability of agroecosystems. In this context, the aim of this study is to estimate variations in soil carbon stocks resulting from land use and management changes in different biomes that compose the Bacia Estendida do Rio São Francisco (BESF - Extended São Francisco River Basin), between 1985 and 2017. For this, remote sensing data and information from the IBGE agriculture and livestock census were used, in addition to emission factors to estimate soil organic carbon (SOC) changes. The results indicate that BESF had about 5.70 million ha degraded in the analyzed period, in addition to an increase of 0.72 Tg C year-1 in SOC stocks. The sub-medium São Francisco River basin recorded the highest SOC gain, with an increase of 0.54 Tg C ha-1; on the other hand, the sub-medium São Francisco River sub-basin had the greatest SOC losses, with an estimated reduction of 0.07 Tg C year-1. In short, this study provides important evidence on changes in SOC stocks in the region, emphasizing the importance of native vegetation conversion to agriculture and livestock systems under sustainable soil management for mitigating greenhouse gas emissions and maintaining soil quality.

From forest to pastures and silvopastoral systems: Soil carbon and nitrogen stocks changes in northeast Amazônia

The Cerrado-Amazon ecotone has been under intense pressure over the years from agricultural and urban expansion, both of which are land uses that directly affect soil quality. The objective of this work was to evaluate the responses of soil carbon and nitrogen stocks, soil organic matter (SOM) quality, carbon isotopic composition (13C) from C3 and C4 plants and carbon sequestration and emission to silvopastoral systems, natural vegetation (NV), fallow pasture (FP), and intensive management pasture (IMP). Silvopastoral systems had different shading levels: 25 % (SP25), 50 % (SP50) and 75 % (SP75). The grass cultivated in all treatments was Megathyrsus maximus cv. Mombaça. The experimental design consisted of four replicates, and collection sites were distributed in strips throughout the study areas at different soil layers (0.00–0.05; 0.05–0.15; 0.15–0.30; 0.30–0.60 and 0.60–1.0 m deep). The conversion of natural vegetation in FP areas and silvopastoral systems (SP25 and SP75) led to increases in total C and N stocks (up to 1.0 m) when compared to other land use systems (SP50, IMP, and NV), which did not occur with total labile-C and C-POM. FP, SP25 and SP75 significantly increased labile C stocks in MAOM found in the 0.30–0.60 m layer. A greater enrichment of 13C in MAOM was observed with increasing depth for silvopastoral systems (SP25, SP50 and SP75) and NV. C-MAOM stocks derived from C3 plants were higher in soils under SP25 and SP75 and from C4 plants under FP. C-POM stocks were higher in all silvopastoral systems under study. IMP and FP affected δ13C values in MAOM and POM, especially in the 0.00–0.05 m layer. C sequestration increased under FP and SP25, with greater contributions from C4 and C3 plants, respectively. Of the silvopastoral systems, SP25 had the highest C stock in soil and contributed to the sequestration of 1.67 Mg C ha−1 yr−1.

Environmental Changes in a Key Region of the Pampa: A Quantitative Analysis of Land use in the Ibirapuitã Environmental Protection area (Rio Grande do Sul) and Surroundings

Objective: To analyze land use patterns in the Environmental Protection Area (APA) of Ibirapuitã (Rio Grande do Sul, RS) and surrounding municipalities between 1985 and 2022. Theoretical framework: Although the South Brazilian Pampa biome is traditionally associated with low-impact agriculture, there is a recent advance in the conversion of natural vegetation in areas of remnants of native fields such as southwestern RS. This region is home to the Ibirapuitã APA, the largest conservation unit in the Pampa biome in RS (more than 300,000 ha). Methods: Based on land use maps obtained from the MapBiomas platform, the areas of each land use class were extracted and quantified using geoprocessing techniques. We then compared the annual trajectories of land use classes in the internal perimeter of the APA and the surrounding area using descriptive statistics. Results: During the analyzed period, the areas of natural land use classes (native grassland and forest) remained stable within the APA, while in the surrounding municipalities the areas of native grasslands were markedly reduced and mostly replaced by agriculture and urbanization. Implications: The Ibirapuitã APA proved to be strategic for the conservation of native fields in this region of the southern Brazilian Pampas. Novelty: By comparing land use trajectories in the internal perimeter and surroundings of the conservation unit, this study provides the first assessment of the effectiveness of the Ibirapuitã APA in maintaining the natural vegetation of the South-Brazilian Pampa biome.

Land use change analysis and modeling of its future trajectories in Morogoro Region, Tanzania: Implication for conservation

In Sub-Saharan Africa, where people's livelihoods depend largely on natural resources, understanding land use change dynamics and its implications for the sustainability of social-ecological systems is critical. This study analyzed both historic land use and land cover (LULC) change and trajectories for future change in the Morogoro Region, Tanzania. We mapped LULC in the study area for 1994, 2007 and 2020 using Random Forest in Google Earth Engine and projected future LULC in 2033 using Land Change Modeler. Results revealed that conversion of natural vegetation and wetlands has occurred at a high rate due to cropland expansion and will likely continue over the next decade. Conversion to cropland occurred on the edges of protected areas, in remnant forests and near existing cropland, and was associated with slope, elevation, proximity to settlements and variation in annual precipitation. In landscapes where wildlife shares areas with humans, converting natural vegetation into crop production increases tension and human-wildlife conflicts. Given compounding impacts of a growing human population in Tanzania, and reduced crop yields due to unpredictable rains and prolonged droughts, both human wellbeing and biodiversity conservation require understanding the resulting pressure on land and ecosystems.

Impact of Land Cover Changes on Soil Type Mapping in Plain Areas: Evidence from Tongzhou District of Beijing, China

The flat terrain in the plain areas of Beijing, China makes the land easily accessible for cultivation and farming, providing vast opportunities for agricultural development. Meanwhile, these areas are also crucial for urban construction and economic growth. Soil type mapping plays a key role in understanding soil characteristics and guiding land management practices. However, accurately mapping soil types in plain regions can be challenging due to their low spatial variability and diverse land use types. Although land cover changes due to phenomena such as urbanization, agricultural expansion, and conversion of natural vegetation can significantly affect soil properties and distribution patterns, their impacts on soil type mapping remain unclear. This study investigated the impacts of land cover changes in plain areas on the accuracy of soil type mapping, hoping to provide effective assistance for soil type mapping in plain areas by analyzing their coupling relationship. Focusing on the 20 year land cover changes in Tongzhou District, this study utilizes a unified approach that combines expert knowledge, mixed sampling methods, and RF mapping techniques, while incorporating environmental covariates that have minimal period influence and synergistically using NDVI and land cover data from the same year. Transition matrices are used to reveal land cover changes, confusion matrices, and their derived indicators to analyze changes in soil type mapping accuracy, and coupling analysis is conducted between soil type change areas and land cover change areas. The results show that Tongzhou District has experienced rapid development over the past 20 years, with the area of construction land nearly doubling. Additionally, 29% of arable land has been converted into construction land, resulting in an increase in the accuracy of the soil map from 58.99% to 66.91% over the 20 year period. The soil type change area during this period accounts for 16.5% of the total area, with 51.9% of the changed areas overlapping with land cover change areas. These overlapping regions are predominantly influenced by human activities. In terms of cultivated land types in the study area, the quantity of arable land has decreased by approximately 29% over 20 years, while the proportion of Sandy loam calcareous fluvo-aquic soil and Light loam calcareous fluvo-aquic soil, which constitute nearly half of the soil type, has increased. These data demonstrate the coupling relationship between land cover changes and soil type variations. It is evident that improving the extent of land use in plain areas enhances the credibility of soil type mapping. Meanwhile, human activities impact land cover, which, in turn, affects and reflects changes in the soil type.

Long-term impact of conventional management on soil carbon and nitrogen stocks in the semi-arid region of Brazil: A meta-analysis

The conversion of native vegetation to agricultural systems has impacted soil carbon and nitrogen stocks in tropical regions, with their maintenance, increase and losss depending on several factors, such as climate, cultivation time, management, depth and classe of soil. Our aim, therefore, was to evaluate the impact of converting areas under Caatinga vegetation to conventional agricultural systems (cropland and pasture) on stocks of carbon (soil organic carbon - SOC; labile carbon - CL and non-labile carbon - CnL) and nitrogen by means of a meta-analysis. In the present research, seven studies were used, with a total of 76 paired comparisons on 14 farms distributed over seven municipalities in three states in the semi-arid region of Brazil were identified from the literature. A dataset of 44 paired comparisons was formed: 14 from areas of native Caatinga vegetation (references), 25 with annual crops, and five under pasture, which came from. The effect of converting Caatinga to conventional systems in the semi-arid region was markedly negative, generating average losses of 10.78%, 9.51%, 23.53% and 15.36% for SOC, nitrogen, CL and CnL, respectively. The loss of nitrogen and carbon stocks (SOC, CL and CnL) decreases with soil depth. The most sensitive soil classes to a change in land use in the semi-arid region of Brazil were the Alfisols, Aridisols and Ultisols, while the Inceptisols showed gains in SOC and CnL.

Beach morphodynamics modulate the effects of multidirectional habitat loss on population density and size structure of the Atlantic ghost crab Ocypode quadrata

Sandy beaches are land-sea transitional habitats experiencing ‘multidirectional’ habitat loss due to coastal developments (e.g. armoring and/or conversion of natural vegetation into manmade structures) and beach erosion. This ‘coastal squeeze’ is a chronic and progressive process; however, its impacts on beach biodiversity across morphodynamic gradients are still to be unveiled. We hypothesized that the effects of multidirectional habitat loss would be more severe on dissipative than on reflective beaches, due to the higher elevation, amount of built up sediment, and width of the backshore compartment of the latter. We, thus, examined the effects of coastal developments and erosion on density and size structure of the Atlantic ghost crab, Ocypode quadrata, on beaches with different morphodynamics. Given that the living area of ghost crabs spans all cross-shore compartments and the whole dissipative-to-reflective morphodynamic gradient, they are appropriate organisms to access the synergic effects of coastal developments and beach erosion under different morphodynamic regimes. On dissipative beaches, density and mean crab size increased with moderate erosion, attributed to the effects of space loss, which might increase territorial competition, favoring the remaining larger individuals. However, mean size and density decreased with high erosion given the more intense reduction in the abundance of large-sized crabs living in up-shore habitats. Mean crab size also decreased in the presence of coastal development while crab density did not vary with loss of backshore habitats occupied by larger individuals. On reflective beaches, both density and crab size decreased with coastal development; the crab size decrease recorded under moderate erosion was more evident in the presence of coastal development. Under high erosion, mean crab sizes declined, reflecting those under low erosion conditions. Overall, populations on reflective beaches appeared more resilient to extreme erosion. Notwithstanding, coastal developments affected population structure across all beach types, and especially in areas subjected to high erosion, exhibiting a synergic effect. We predict that, in combination, these stressors may lead to functionally extinct populations where conditions necessary for individuals to reach sexual maturity (i.e. occurrence of only small-sized and immature individuals) are not met. Thus, the connectivity between water, beach compartments and dunes/coastal plain, on both local and regional scales, may be essential to maintain viable and connected populations of ghost crabs. Further, our results strongly suggest that both size and density (complemented with crab abundance) must be considered equally important and in combination in future efforts to assess anthropogenic stressors on ghost crab populations and when guiding conservation strategies and policies to prevent their local and regional extinctions.

Severe simplification of the structure of dung beetle assemblages in neotropical soybean croplands regardless of the native vegetation domain

The conversion of native vegetation into agricultural areas is arguably the key driver of biodiversity declines globally. We assessed the responses of dung beetle assemblages (Coleoptera: Scarabaeidae: Scarabaeinae) to the effects of native vegetation conversion into soybean monoculture in different vegetation domains (Amazonian forest, scrubland savannahs and transitional vegetation) in the world’s largest tropical soybean (Glycine max L.) agricultural frontier. We also assessed the effects of landscape variables (amount of native habitat and amount of pasture) and land use history (time of land use change including soybean cultivation and cattle pastures). We sampled dung beetles at 100 study landscapes throughout the state of Mato Grosso, Brazil, within a region encompassing Amazonian forests, the drier Cerrado savannahs, and transitional vegetation domain between these biomes. In total, we recorded 71,043 individuals of 165 species, with 39,090 individuals (155 species) sampled in native vegetation and 31,953 individuals (75 species) in soybean monoculture areas, 30 species of which could persist in croplands. We found differences in species composition, and lower species richness, overall abundance and biomass in monoculture areas, compared to adjacent native habitat. Time since land-use change into pasture was the main determinant of species richness and species compositional similarity in monocultures, while none of the landscape and land use history variables were informative in explaining overall abundance. We provide clear evidence that the conversion of native vegetation into soybean monoculture negatively affects dung beetle assemblages. Furthermore, croplands harboured their own unique dung beetle assemblages containing species typical of open-habitats and pasturelands, which are likely tracking the historical advance of the agricultural frontier. However, species typical of forest environments were most detrimentally affected and were largely missing in cropland areas.

Effects of land use/land cover changes on soil properties in Rib watershed, Ethiopia

Conversion of natural vegetation into farm land and grazing land causes soil quality loss. Soil properties response to land use/land cover changes (LULC) shows both spatial and temporal variations. This study was aimed at assessing the effects of LULC changes on physical and chemical properties of soil in Rib watershed. To assess physical and chemical properties of the soil among LULC, soil samples were taken over natural forest, grazing and cultivated lands in two agro-ecological belts of Dega and High Dega. Multivariate analysis of variance (MANOVA) and Pearson’s correlation were computed. The study revealed that LULC and agro-ecology have affected physical and chemical properties of the soil in the study watershed. Significant difference in distribution of soil texture, BD, OC, TN and pH among LULC were observed. Soils of Natural forest had higher OC, OC stock and TN. For instance, soils of natural forest had higher OC stock (188.32 Mg/ha) as compared to soils of cultivated lands(72.75 Mg/ha). Soil pH was slightly higher in natural forests and lower in the soils of grazing and cultivated lands. Significant difference (P < 0.05) among the two agro-ecologies were also observed in OC, Ca2+, and contents of clay and silt. In general, LULC change has affected the concentration of TN, OC, pH and BD which in turn can affect soil productivity. Therefore, the study suggests the implementation of an integrated soil fertility management practices and conservation based production systems with the collaboration of regional, local authority and farming community.

Shifting agriculture and a depleting aquifer: implications of row-crop farming on mule deer population performance

Context Conversion of native vegetation to cropland is one of the most widespread anthropogenic landscape alterations, particularly in the Great Plains region of the United States. Mule deer occur throughout the Great Plains; however, it is the south-eastern edge of their geographical distribution, and few populations coincide with dense cropland. The rapidly depleting Ogallala Aquifer supplies irrigation to row-crops throughout the region, which will likely shift towards dryland agricultural practices in the near future. Aims We sought to understand how cropland use influences morphology, body condition indices, reproductive output, and survival of free-ranging mule deer. Methods We accumulated a multi-year, longitudinal dataset of movement and morphology for 146 mule deer in the Texas Panhandle. We linked seasonal cropland use with observed morphology, body condition metrics, and reproductive output via linear mixed-effect modelling and assessed the influence of cropland on annual survival by using Cox proportional hazard models. Key results Mule deer that did not use cropland at any time during the year exhibited morphological and nutritional indices similar to those that did; except body-fat percentage being greater for mature (≥4-year-old) males that used cropland. Further, cropland use did not predict survival probability. Analyses of cropland use during seasons defined by life-stage showed context-dependent nutritional benefits. Use of cropland during winter following reproduction demonstrated an increase in young (≤3-year-old) male antler size and body mass and summer crop use increased body condition for all males. Female mule deer that utilised cropland before pregnancy had increased probability of successful reproduction, demonstrating a potential capital investment strategy in reproduction. Conclusions Cropland does not limit morphology or survival of mule deer; however, additive use of row-crops can provide a nutritional buffer and enhanced reproductive output for individuals that choose to utilise it. Implications Our study demonstrates important population-level interactions with the environment for a species near the extent of their geographical distribution. Conversion of row-crop farming from aquifer depletion or climate shifts may not diminish mule deer populations, but these changes may alter specific habitat-nutritional health relationships that can influence population performance and future conservation efforts.

Diversity Loss of Epigeic Collembola after Grassland Conversion into Eucalyptus Forestry in Brazilian Pampa Domain

The Brazilian Pampa is a rich domain mainly represented by grasslands. Conversion of native vegetation into Eucalyptus plantation leads to soil degradation and losses on local fauna and flora. The objectives of this study were to compare the taxonomic structure and abundance of epigeic springtails (Collembola) in two different types of land-use in the Brazilian Pampa, native grassland and Eucalyptus plantation, as well as to understand the processes that may cause species loss after grassland afforestation. Specimens were sampled in 10 paired plots of grasslands and Eucalyptus in southern Brazil. After sampling, all specimens were sorted, counted and identified. We evaluated the taxonomic composition, alpha and beta diversity, and used Random Forest Analysis to understand the influence of environmental factors on the structure and composition of Collembola communities. We sampled 1249 specimens in 26 morphospecies, and our data support there are significant losses in native Collembola communities after the conversion of grasslands into Eucalyptus plantations regarding abundance, species composition, richness, and alpha diversity. Species turnover better explained the beta diversity, and plant richness and dominance were the main environmental factors driving the Collembola diversity. These results deepen the knowledge of the impacts of native grassland conversion on soil fauna.

Potential of no-till agriculture as a nature-based solution for climate-change mitigation in Brazil

Despite increasing efforts to combat climate change, greenhouse gas (GHG) emissions continued to grow. In this context, conservationist agricultural systems such as no-till (NT) can play an important role. However, the potential of this system to mitigate GHG emissions has been questioned more recently. Brazil is the second country with the largest NT area, representing around 18% of the global area under NT. Here, we examined the effects of the adoption of NT from the conversion of native vegetation, conventional tillage (CT), and pasture in layers 0–30 and 0–50 cm of the soil. We used a total of 124 comparison pairs to analyze changes in soil organic carbon (SOC) using two approaches (deriving SOC change factors and the adjustment of empirical equations on SOC temporal dynamics). Our results showed that the adoption of NT in NV areas reduces SOC stocks by between 4% and 8%. However, in areas previously managed by CT systems or pasture, NT is a potential alternative for promoting carbon sequestration in agricultural soils in Brazil's different regions. The results showed that the SOC accumulation is not restricted to superficial layers of the soil (0–30 cm) but was also effective up to 50 cm in depth, with gains varying between 9% and 25%. Thus, our results consistently demonstrate that for Brazilian conditions, NT when compared to CT systems or pastures, predominantly result in SOC gains, and represent an alternative to promote sustainable agriculture, which can contribute to the mitigation of GHG emissions and food security.

Spatial patterns of soil salinity in the central Argentinean Dry Chaco

The Dry Chaco is a semi-arid ecoregion in South America that hosts one of the largest dry forests in the world, but expansion of dryland agriculture and cattle ranching led to gradual conversion of native vegetation to anthropogenic land cover. The potential impact of these newly established agricultural lands on the surrounding environment is of great concern. Local studies have shown that deforestation leads to changes in the soil-water balance, and can expedite groundwater rise and mobilization of water-soluble salts to the surface affecting plant growth and crop productivity. This study is a regional assessment of soil salinity and salinization processes in the central Argentinean Dry Chaco. It is based on extensive dataset of 492 surface and 142 subsurface samples taken along east-west transects across the Dry Chaco. Soil electrical conductivity (EC) was used as an indicator of salinity, and supplementary information on salt crusts was derived from Google Earth imagery. Subsurface salinity (i.e., measured at 100 cm depth) showed clear regional patterns in natural soil salinity that are related to the annual water budget and topography. Besides primary salinization due to arrested drainage and landscape stagnation, anthropogenic activities increased secondary salinization, especially in the agricultural areas with shallow groundwater tables and irrigated croplands. In addition, the study demonstrated that remotely-sensed vegetation indices such as the seasonal variation in the density of green vegetation are particularly suitable to monitor regional variation in soil salinity. Our results show that the extent of future dryland salinization in the Dry Chaco will mainly depend on whether areas prone to natural soil salinity are further protected from deforestation, and the magnitude and rate of groundwater rise after deforestation as conditioned by local climate and geomorphology. This better understanding of soil salinity patterns and how they are affected as a result of anthropogenic activities is important for the implementation of appropriate and effective measures to prevent severe salinization.

The role of different governance regimes in reducing native vegetation conversion and promoting regrowth in the Brazilian Amazon

Area-based conservation measures, including protected areas (PA) and other effective area-based conservation measures (OECM), play an important role in biodiversity conservation. In the Brazilian Amazon, even though Conservation Units and Indigenous Lands have been shown to reduce deforestation, few studies have addressed Quilombola Territories, and none of the above-mentioned areas were evaluated according to their role in promoting native vegetation regrowth. Here, we used a matching analysis to show that Brazilian Amazon Indigenous Lands, Quilombola Territories, and two types of protected areas (Conservation Units of Restrict Use and Sustainable Use) contribute to reduced native vegetation conversion, when compared to their control areas. Indigenous Lands and Conservation Units of Restrict Use lost respectively 17 and five times less native vegetation cover than their unprotected control areas, between the years of 2005–2012. Similarly, Quilombola Territories had native vegetation loss rates 5.6 times lower than in matched controls. Importantly, our results demonstrate for the first time that between 2012 and 2017 Indigenous Lands and Quilombola Territories contributed two and three times more to native vegetation regrowth – a critical process for safeguarding biodiversity in many, if not all, parts of the world. Our results underscore the importance of areas beyond the formal protected areas system in conserving biodiversity and promoting forest regrowth.

Conversion of Brazilian savannah to agricultural land affects quantity and quality of labile soil organic matter

Most studies assessing land-use change (LUC) and management impacts on the soil organic carbon (SOC) budget mainly focused on total soil organic matter (SOM), neglecting its functional fractions such as water-extractable organic matter (WEOM). This may limit a better understanding of SOC dynamics along the soil profile as WEOM plays a key role in several soil and microbial processes. Here, we aimed to obtain a quantitative and qualitative assessment of WEOM dynamics to 1 m depth in areas after native vegetation conversion to long-term agriculture in Brazil. For this purpose, cropland areas under no-tillage (NT; ∼ 23 years old) and native vegetation (NV; i.e., Cerrado vegetation) were evaluated across a transect of 1000 km within Brazil’s new agricultural frontier – the so-called MATOPIBA region. We combined spectroscopic analyses (UV–Vis and DRIFT spectroscopies), C and nitrogen (N) determination in different SOM pools (i.e., bulk SOM, WEOM, and microbial biomass), and microbial measurements [e.g., microbial biomass C (MBC) and N (MBN), and β-glucosidase activity] to better understand changes in WEOM dynamics induced by LUC. We observed that although SOC decreased along the soil profile after NV (4.2–20.7 g kg−1) conversion to NT (3.8–14.2 g kg−1), water-extractable organic C levels (3.6–79.3 mg L−1) were similar between land uses. On the other hand, an increase in water-extractable total N was observed after NV (0.4–4.6 mg L−1) conversion to NT (0.5–19.3 mg L−1). Although MBC and MBN levels decreased for most study sites, β-glucosidase activity increased after LUC indicating intensive microbial processing of SOM. As a result, WEOM had lower aromaticity and molecular weight (i.e., low values of SUVA254 and A2/A3) in NT than NV; and a relative decomposition of aliphatic and polysaccharides over aromatic and amine/amide was observed after LUC through DRIFT spectroscopy. Our study indicates that LUC had stronger impacts on WEOM quality than its quantity, with agricultural areas having more biochemical changes in WEOM than NV.

Climate change forecasts suggest that the conservation area network in the Cerrado-Amazon transition zone needs to be expanded

Climate change impacts are important in shaping large ecotones, such as the transition zone between the Cerrado and Amazon rainforest (CAT) biogeographical domains. The accelerating rate of conversion of native vegetation, the most important factor for biodiversity loss in the Anthropocene, compounded by projected climate change impacts, requires a review of the effectiveness of existing designated protected areas (PA) and indigenous land (IL), where low-intensity and low-impact land use prevails. We identified priority tree species for conservation and quantified changes in their projected spatial distribution in future climate scenarios to estimate the conservation effectiveness of the current network of PA and IL in the CAT. Applying niche-based models to compare the geographical range of species in current and future climates, we estimated the displacement of species from their current distribution owing to projected climate change. We used four different IPCC emission scenarios for 2050 and quantified the losses or gains in species richness in PA and IL. All species were projected to suffer a reduction of climatically suitable area and a consequent range reduction. Inside both PA and IL there was a projected decrease in richness of the target species under climate change. The current PA network and designated IL in the CAT do not appear to safeguard future conservation of the species they currently contain. The future ‘climate refugia’ that our work identified could form the basis of plans to expand the protected area network in a region that remains under ever increasing pressure of deforestation in Brazil.

Lack of protected areas and future habitat loss threaten the Hyacinth Macaw (Anodorhynchus hyacinthinus) and its main food and nesting resources

Habitat loss is a major reason for population declines and thus increases extinction risk, particularly for endemic or specialist species. Protected areas are an important biodiversity conservation strategy in the face of native vegetation conversion, but local and regional factors such as anthropogenic pressure can jeopardize their effectiveness. The Pantanal biome is one of the largest inland wetlands in the world. Currently, only 11% of the Pantanal is protected, 7% with full protection and 4% under sustainable use. However, 14% of the natural vegetation of the biome was lost between 2002 and 2014, negatively affecting its biodiversity. Here, we analyse how the availability of protected areas and habitat loss affects the conservation of the Hyacinth Macaw Anodorhynchus hyacinthinus, as well as the Acuri Palm Attalea phalerata and the Manduvi Tree Sterculia apetala, its two main resources for food and nesting, respectively. We modelled potential distributions to assess the spatio‐temporal patterns of habitat loss due to the conversion of native vegetation and to evaluate to what degree currently protected areas contribute to the conservation of these three species in the Pantanal. We found that, on average, 11.8% of the suitable habitat had been converted and that 10.6% of habitat predicted as suitable is currently protected. In addition, our results indicated important areas for the three species, which are of high priority for conservation and restoration. We also identified priorities for protection and restoration to maintain native vegetation, such as the creation of corridors. We believe that the high conversion rate and the low protection of suitable areas are related to the fact that these species are associated with areas that are rarely or never flooded. In the Pantanal, these areas are more prone to the conversion of native vegetation and are poorly protected given their higher economic value compared with areas with a high frequency of flooding. These facts, and the inadequate management of these areas, such as inappropriate fire regimens, threaten the persistence of these iconic species in the Pantanal.

Soil carbon stock estimations: methods and a case study of the Maranhão State, Brazil

Soils feature significant variations in soil carbon stocks through land-use changes, management practices, and intrinsic characteristics. The aim of this study was to estimate the changes in soil carbon stock under different scenarios of land use and agricultural management in the Maranhao State, Brazil, considering the conversion from the conventional agriculture into conservationist management systems. Changes in soil carbon stocks were estimated from the scenario t0 to the current scenario (2010), followed by the adoption of a conservationist scenario by the year 2030. Soils under pasturelands presented the highest average of carbon stocks (62.19 Mg ha−1), followed by forestry lands (61.60 Mg ha−1) and agricultural lands (38.28 Mg ha−1). The conversion of native vegetation into an intensive agricultural use contributed to soil carbon losses of 1.57 Mt C, with pasturelands accounting for 1.36 Mt C and agricultural lands for 0.21 Mt C by 2010. The replacement of intensive agricultural systems into conservationist systems in the current areas has a technical potential for soil carbon sequestration of 0.6 Mt by 2030, with livestock and agricultural lands accounting for 0.54 and 0.03 Mt C, respectively.