Michael T. Coe

Land use has generally been considered a local environmental issue, but it is becoming a force of global importance. Worldwide changes to forests, farmlands, waterways, and air are being driven by the need to provide food, fiber, water, and shelter to more than six billion people. Global croplands, pastures, plantations, and urban areas have expanded in recent decades, accompanied by large increases in energy, water, and fertilizer consumption, along with considerable losses of biodiversity. Such changes in land use have enabled humans to appropriate an increasing share of the planet's resources, but they also potentially undermine the capacity of ecosystems to sustain food production, maintain freshwater and forest resources, regulate climate and air quality, and ameliorate infectious diseases. We face the challenge of managing trade-offs between immediate human needs and maintaining the capacity of the biosphere to provide goods and services in the long term.

Brazil's controversial new Forest Code grants amnesty to illegal deforesters, but creates new mechanisms for forest conservation.

While a new class of Dynamic Global Ecosystem Models (DGEMs) has emerged in the past few years as an important tool for describing global biogeochemical cycles and atmosphere‐biosphere interactions, these models are still largely untested. Here we analyze the behavior of a new DGEM and compare the results to global‐scale observations of water balance, carbon balance, and vegetation structure. In this study, we use version 2 of the Integrated Biosphere Simulator (IBIS), which includes several major improvements and additions to the prototype model developed by Foley et al. [1996]. IBIS is designed to be a comprehensive model of the terrestrial biosphere; the model represents a wide range of processes, including land surface physics, canopy physiology, plant phenology, vegetation dynamics and competition, and carbon and nutrient cycling. The model generates global simulations of the surface water balance (e.g., runoff), the terrestrial carbon balance (e.g., net primary production, net ecosystem exchange, soil carbon, aboveground and belowground litter, and soil CO 2 fluxes), and vegetation structure (e.g., biomass, leaf area index, and vegetation composition). In order to test the performance of the model, we have assembled a wide range of continental and global‐scale data, including measurements of river discharge, net primary production, vegetation structure, root biomass, soil carbon, litter carbon, and soil CO 2 flux. Using these field data and model results for the contemporary biosphere (1965–1994), our evaluation shows that simulated patterns of runoff, NPP, biomass, leaf area index, soil carbon, and total soil CO 2 flux agree reasonably well with measurements that have been compiled from numerous ecosystems. These results also compare favorably to other global model results.

Interactions between climate and land-use change may drive widespread degradation of Amazonian forests. High-intensity fires associated with extreme weather events could accelerate this degradation by abruptly increasing tree mortality, but this process remains poorly understood. Here we present, to our knowledge, the first field-based evidence of a tipping point in Amazon forests due to altered fire regimes. Based on results of a large-scale, long-term experiment with annual and triennial burn regimes (B1yr and B3yr, respectively) in the Amazon, we found abrupt increases in fire-induced tree mortality (226 and 462%) during a severe drought event, when fuel loads and air temperatures were substantially higher and relative humidity was lower than long-term averages. This threshold mortality response had a cascading effect, causing sharp declines in canopy cover (23 and 31%) and aboveground live biomass (12 and 30%) and favoring widespread invasion by flammable grasses across the forest edge area (80 and 63%), where fires were most intense (e.g., 220 and 820 kW ⋅ m(-1)). During the droughts of 2007 and 2010, regional forest fires burned 12 and 5% of southeastern Amazon forests, respectively, compared with <1% in nondrought years. These results show that a few extreme drought events, coupled with forest fragmentation and anthropogenic ignition sources, are already causing widespread fire-induced tree mortality and forest degradation across southeastern Amazon forests. Future projections of vegetation responses to climate change across drier portions of the Amazon require more than simulation of global climate forcing alone and must also include interactions of extreme weather events, fire, and land-use change.

The Amazon Basin is one of the world's most important bioregions, harboring a rich array of plant and animal species and offering a wealth of goods and services to society. For years, ecological science has shown how large-scale forest clearings cause declines in biodiversity and the availability of forest products. Yet some important changes in the rainforests, and in the ecosystem services they provide, have been underappreciated until recently. Emerging research indicates that land use in the Amazon goes far beyond clearing large areas of forest; selective logging and other canopy damage is much more pervasive than once believed. Deforestation causes collateral damage to the surrounding forests – through enhanced drying of the forest floor, increased frequency of fires, and lowered productivity. The loss of healthy forests can degrade key ecosystem services, such as carbon storage in biomass and soils, the regulation of water balance and river flow, the modulation of regional climate patterns, and the amelioration of infectious diseases. We review these newly revealed changes in the Amazon rainforests and the ecosystem services that they provide.

We present a model of the dust cycle that successfully predicts dust emissions as determined by land surface properties, monthly vegetation and snow cover, and 6‐hourly surface wind speeds for the years 1982–1993. The model takes account of the role of dry lake beds as preferential source areas for dust emission. The occurrence of these preferential sources is determined by a water routing and storage model. The dust source scheme also explicitly takes into account the role of vegetation type as well as monthly vegetation cover. Dust transport is computed using assimilated winds for the years 1987–1990. Deposition of dust occurs through dry and wet deposition, where subcloud scavenging is calculated using assimilated precipitation fields. Comparison of simulated patterns of atmospheric dust loading with the Total Ozone Mapping Spectrometer satellite absorbing aerosol index shows that the model produces realistic results from daily to interannual timescales. The magnitude of dust deposition agrees well with sediment flux data from marine sites. Emission of submicron dust from preferential source areas are required for the computation of a realistic dust optical thickness. Sensitivity studies show that Asian dust source strengths are particularly sensitive to the seasonality of vegetation cover.

Abstract The hydrological connectivity of freshwater ecosystems in the Amazon basin makes them highly sensitive to a broad range of anthropogenic activities occurring in aquatic and terrestrial systems at local and distant locations. Amazon freshwater ecosystems are suffering escalating impacts caused by expansions in deforestation, pollution, construction of dams and waterways, and overharvesting of animal and plant species. The natural functions of these ecosystems are changing, and their capacity to provide historically important goods and services is declining. Existing management policies—including national water resources legislation, community‐based natural resource management schemes, and the protected area network that now epitomizes the Amazon conservation paradigm—cannot adequately curb most impacts. Such management strategies are intended to conserve terrestrial ecosystems, have design and implementation deficiencies, or fail to account for the hydrologic connectivity of freshwater ecosystems. There is an urgent need to shift the Amazon conservation paradigm, broadening its current forest‐centric focus to encompass the freshwater ecosystems that are vital components of the basin. This is possible by developing a river catchment‐based conservation framework for the whole basin that protects both aquatic and terrestrial ecosystems.

Abstract Historically, conservation‐oriented research and policy in Brazil have focused on Amazon deforestation, but a majority of Brazil's deforestation and agricultural expansion has occurred in the neighboring Cerrado biome, a biodiversity hotspot comprised of dry forests, woodland savannas, and grasslands. Resilience of rainfed agriculture in both biomes likely depends on water recycling in undisturbed Cerrado vegetation; yet little is known about how changes in land‐use and land‐cover affect regional climate feedbacks in the Cerrado. We used remote sensing techniques to map land‐use change across the Cerrado from 2003 to 2013. During this period, cropland agriculture more than doubled in area from 1.2 to 2.5 million ha, with 74% of new croplands sourced from previously intact Cerrado vegetation. We find that these changes have decreased the amount of water recycled to the atmosphere via evapotranspiration (ET) each year. In 2013 alone, cropland areas recycled 14 km 3 less (−3%) water than if the land cover had been native Cerrado vegetation. ET from single‐cropping systems (e.g., soybeans) is less than from natural vegetation in all years, except in the months of January and February, the height of the growing season. In double‐cropping systems (e.g., soybeans followed by corn), ET is similar to or greater than natural vegetation throughout a majority of the wet season (December–May). As intensification and extensification of agricultural production continue in the region, the impacts on the water cycle and opportunities for mitigation warrant consideration. For example, if an environmental goal is to minimize impacts on the water cycle, double cropping (intensification) might be emphasized over extensification to maintain a landscape that behaves more akin to the natural system.

In this study, results from two sets of numerical simulations are evaluated and presented; one with the land surface model IBIS forced with prescribed climate and another with the fully coupled atmospheric general circulation and land surface model CCM3-IBIS. The results illustrate the influence of historical and potential future deforestation on local evapotranspiration and discharge of the Amazon River system with and without atmospheric feedbacks and clarify a few important points about the impact of deforestation on the Amazon River. In the absence of a continental scale precipitation change, large-scale deforestation can have a significant impact on large river systems and appears to have already done so in the Tocantins and Araguaia Rivers, where discharge has increased 25% with little change in precipitation. However, with extensive deforestation (e.g. >30% of the Amazon basin) atmospheric feedbacks, brought about by differences in the physical structure of the crops and pasture replacing natural vegetation, cause water balance changes of the same order of magnitude as the changes due to local land surface processes, but of opposite sign. Additionally, changes in the water balance caused by atmospheric feedbacks are not limited to those basins where deforestation has occurred but are spread unevenly throughout the entire Amazon by atmospheric circulation. As a result, changes to discharge and aquatic environments with future deforestation of the Amazon will likely be significant and a complex function of how much vegetation has been removed from that particular watershed and how much has been removed from the entire Amazon Basin.

Abstract Large‐scale wildfires are expected to accelerate forest dieback in Amazônia, but the fire vulnerability of tree species remains uncertain, in part due to the lack of studies relating fire‐induced mortality to both fire behavior and plant traits. To address this gap, we established two sets of experiments in southern Amazonia. First, we tested which bark traits best predict heat transfer rates ( R ) through bark during experimental bole heating. Second, using data from a large‐scale fire experiment, we tested the effects of tree wood density ( WD ), size, and estimated R (inverse of cambium insulation) on tree mortality after one to five fires. In the first experiment, bark thickness explained 82% of the variance in R , while the presence of water in the bark reduced the difference in temperature between the heat source and the vascular cambium, perhaps because of high latent heat of vaporization. This novel finding provides an important insight for improving mechanistic models of fire‐induced cambium damage from tropical to temperate regions. In the second experiment, tree mortality increased with increasing fire intensity (i.e. as indicated by bark char height on tree boles), which was higher along the forest edge, during the 2007 drought, and when the fire return interval was 3 years instead of one. Contrary to other tropical studies, the relationship between mortality and fire intensity was strongest in the year following the fires, but continued for 3 years afterwards. Tree mortality was low (≤20%) for thick‐barked individuals (≥18 mm) subjected to medium‐intensity fires, and significantly decreased as a function of increasing tree diameter, height and wood density. Hence, fire‐induced tree mortality was influenced not only by cambium insulation but also by other traits that reduce the indirect effects of fire. These results can be used to improve assessments of fire vulnerability of tropical forests.

Tropical rainforest regions have large hydropower generation potential that figures prominently in many nations' energy growth strategies. Feasibility studies of hydropower plants typically ignore the effect of future deforestation or assume that deforestation will have a positive effect on river discharge and energy generation resulting from declines in evapotranspiration (ET) associated with forest conversion. Forest loss can also reduce river discharge, however, by inhibiting rainfall. We used land use, hydrological, and climate models to examine the local "direct" effects (through changes in ET within the watershed) and the potential regional "indirect" effects (through changes in rainfall) of deforestation on river discharge and energy generation potential for the Belo Monte energy complex, one of the world's largest hydropower plants that is currently under construction on the Xingu River in the eastern Amazon. In the absence of indirect effects of deforestation, simulated deforestation of 20% and 40% within the Xingu River basin increased discharge by 4-8% and 10-12%, with similar increases in energy generation. When indirect effects were considered, deforestation of the Amazon region inhibited rainfall within the Xingu Basin, counterbalancing declines in ET and decreasing discharge by 6-36%. Under business-as-usual projections of forest loss for 2050 (40%), simulated power generation declined to only 25% of maximum plant output and 60% of the industry's own projections. Like other energy sources, hydropower plants present large social and environmental costs. Their reliability as energy sources, however, must take into account their dependence on forests.

Upper Xingu River Basin, southeastern Amazonia. This study assessed the influence of land cover changes on evapotranspiration and streamflow in small catchments in the Upper Xingu River Basin (Mato Grosso state, Brazil). Streamflow was measured in catchments with uniform land use for September 1, 2008 to August 31, 2010. We used models to simulate evapotranspiration and streamflow for the four most common land cover types found in the Upper Xingu: tropical forest, cerrado (savanna), pasture, and soybean croplands. We used INLAND to perform single point simulations considering tropical rainforest, cerrado and pasturelands, and AgroIBIS for croplands. Converting natural vegetation to agriculture substantially modifies evapotranspiration and streamflow in small catchments. Measured mean streamflow in soy catchments was about three times greater than that of forest catchments, while the mean annual amplitude of flow in soy catchments was more than twice that of forest catchments. Simulated mean annual evapotranspiration was 39% lower in agricultural ecosystems (pasture and soybean cropland) than in natural ecosystems (tropical rainforest and cerrado). Observed and simulated mean annual streamflows in agricultural ecosystems were more than 100% higher than in natural ecosystems. The accuracy of the simulations was improved by using field-measured soil hydraulic properties. The inclusion of local measurements of key soil parameters is likely to improve hydrological simulations in other tropical regions.

Amazon wildfires could emit 17.0 Pg of CO 2 by 2050, and avoiding new deforestation could cut associated net emissions by half.

Tropical woody plants store ∼230 petagrams of carbon (PgC) in their aboveground living biomass. This review suggests that these stocks are currently growing in primary forests at rates that have decreased in recent decades. Droughts are an important mechanism in reducing forest C uptake and stocks by decreasing photosynthesis, elevating tree mortality, increasing autotrophic respiration, and promoting wildfires. Tropical forests were a C source to the atmosphere during the 2015–2016 El Niño–related drought, with some estimates suggesting that up to 2.3 PgC were released. With continued climate change, the intensity and frequency of droughts and fires will likely increase. It is unclear at what point the impacts of severe, repeated disturbances by drought and fires could exceed tropical forests’ capacity to recover. Although specific threshold conditions beyond which ecosystem properties could lead to alternative stable states are largely unknown, the growing body of scientific evidence points to such threshold conditions becoming more likely as climate and land use change across the tropics. ▪ Droughts have reduced forest carbon uptake and stocks by elevating tree mortality, increasing autotrophic respiration, and promoting wildfires. ▪ Threshold conditions beyond which tropical forests are pushed into alternative stable states are becoming more likely as effects of droughts intensify.

Brazil has become an agricultural powerhouse, producing roughly 30 % of the world's soy and 15 % of its beef by 2013 – yet historically much of that growth has come at the expense of its native ecosystems. Since 1985, pastures and croplands have replaced nearly 65 Mha of forests and savannas in the legal Amazon. A growing body of work suggests that this paradigm of horizontal expansion of agriculture over ecosystems is outdated and brings negative social and environmental outcomes. Here we propose four strategies that can reduce deforestation, while increasing production and social wellbeing. First, eliminate land grabbing and land speculation through designation of public forests. This would clarify land tenure and limit the pool of land available for uncontrolled expansion of agriculture and ranching. Second, reduce deforestation on private properties by implementing existing mechanisms in Brazil's Forest Code to facilitate payments for environmental services, with support from market initiatives for sustainable sourcing of agricultural products. Third, incentivize increased productivity on medium and large properties through targeted investments. By stimulating adoption of proven technologies for sustainable intensification, this would help meet Brazil's production targets and growing international demand for agricultural products, without expanding into new production areas. Finally, foster economic, environmental and social improvements through technical assistance to small farmers. Small farmers occupy a large swath of the Amazon and often lack access to technical assistance, production technology, and markets. Providing quality technical assistance to small farmers could help them better align production practices with local opportunities; increase household income and improve livelihoods; and reduce deforestation pressure. By implementing these four strategies in a coordinated effort between public and private agents, Brazil can show the world how to reduce deforestation while increasing agricultural output, reestablishing its leadership in managing natural resources and mitigating climate change.

Climate policy has thus far focused solely on carbon stocks and sequestration to evaluate the potential of forests to mitigate global warming. These factors are used to assess the impacts of different drivers of deforestation and forest degradation as well as alternative forest management. However, when forest cover, structure and composition change, shifts in biophysical processes (the water and energy balances) may enhance or diminish the climate effects of carbon released from forest aboveground biomass. The net climate impact of carbon effects and biophysical effects determines outcomes for forest and agricultural species as well as the humans who depend on them. Evaluating the net impact is complicated by the disparate spatio-temporal scales at which they operate. Here we review the biophysical mechanisms by which forests influence climate and synthesize recent work on the biophysical climate forcing of forests across latitudes. We then combine published data on the biophysical effects of deforestation on climate by latitude with a new analysis of the climate impact of the CO 2 in forest aboveground biomass by latitude to quantitatively assess how these processes combine to shape local and global climate. We find that tropical deforestation leads to strong net global warming as a result of both CO 2 and biophysical effects. From the tropics to a point between 30°N and 40°N, biophysical cooling by standing forests is both local and global, adding to the global cooling effect of CO 2 sequestered by forests. In the mid-latitudes up to 50°N, deforestation leads to modest net global warming as warming from released forest carbon outweighs a small opposing biophysical cooling. Beyond 50°N large scale deforestation leads to a net global cooling due to the dominance of biophysical processes (particularly increased albedo) over warming from CO 2 released. Locally at all latitudes, forest biophysical impacts far outweigh CO 2 effects, promoting local climate stability by reducing extreme temperatures in all seasons and times of day. The importance of forests for both global climate change mitigation and local adaptation by human and non-human species is not adequately captured by current carbon-centric metrics, particularly in the context of future climate warming.

An integrated biosphere model (IBIS) and a hydrological routing algorithm (HYDRA) are used in conjunction with long time‐series climate data to investigate the response of the Lake Chad drainage basin of northern Africa to climate variability and water use practices over the last 43 years. The simulated discharge, lake level, and lake area of the drainage basin for the period 1953–1979 are in good agreement with the observations. For example, the correlation coefficient ( r 2 ) between the simulated and the observed level of Lake Chad for the 288 months of available observations is 0.93. Although irrigation is only a modest portion of the hydrology in the period 1953–1979; representing only 5 of the 30% decrease in simulated lake area for the decade 1966–1975, the simulated lake level and area are in better agreement with the observations when irrigation is included. For the period 1983–1994 the observed water use for irrigation increased fourfold compared to 1953–1979. A comparison of the simulated surface water area, with and without irrigation, suggests that climate variability still controls the interannual fluctuations of the water inflow but that human water use accounts for roughly 50% of the observed decrease in lake area since the 1960s and 1970s.

Numerical simulations of idealized deforestation and overgrazing are performed for the Niger and Lake Chad basins of West Africa with a terrestrial ecosystem model IBIS (integrated biosphere simulator) and an aquatic transport model THMB (terrestrial hydrology model with biogeochemistry). The study reveals how land use changes affect hydrological regimes at the watershed scale. The results show that tropical forests, due to being situated in the regions of highest rainfall and exerting strong influence on evapotranspiration, have a disproportionately large impact on the water balance of the entire basin. Total deforestation (clearcutting) increases the simulated runoff ratio from 0.15 to 0.44, and the annual streamflow by 35–65%, depending on location in the basin, although forests occupy only a small portion (<5%) of the total basin area. Complete removal of grassland and savanna, which occupy much greater areas of the basins, result in an increase in simulated annual streamflow by 33–91%. The numerical simulations indicate that the hydrological response to progressive land cover change is non-linear and exhibits a threshold effect. There is no significant impact on the water yield and river discharge when the deforestation (thinning) percentage is below 50% or the overgrazing percentage below 70% for savanna and 80% for grassland areas; however, the water yield is increased dramatically when land cover change exceeds these thresholds. This threshold effect is a combined result of the non-linearity of the separate response of transpiration and soil and canopy evaporation to the imposed land cover changes.

Abstract The United Nations climate treaty may soon include a mechanism for compensating tropical nations that succeed in reducing carbon emissions from deforestation and forest degradation, source of nearly one fifth of global carbon emissions. We review the potential for this mechanism [reducing emissions from deforestation and degradation (REDD)] to provoke ecological damages and promote ecological cobenefits. Nations could potentially participate in REDD by slowing clear‐cutting of mature tropical forest, slowing or decreasing the impact of selective logging, promoting forest regeneration and restoration, and expanding tree plantations. REDD could also foster efforts to reduce the incidence of forest fire. Potential ecological costs include the accelerated loss (through displaced agricultural expansion) of low‐biomass, high‐conservation‐value ecosystems, and substitution of low‐biomass vegetation by monoculture tree plantations. These costs could be avoided through measures that protect low‐biomass native ecosystems. Substantial ecological cobenefits should be conferred under most circumstances, and include the maintenance or restoration of (1) watershed functions, (2) local and regional climate regimes, (3) soils and biogeochemical processes, (4) water quality and aquatic habitat, and (5) terrestrial habitat. Some tools already being developed to monitor, report and verify (MRV) carbon emissions performance can also be used to measure other elements of ecosystem function, making development of MRV systems for ecological cobenefits a concrete possibility. Analysis of possible REDD program interventions in a large‐scale Amazon landscape indicates that even modest flows of forest carbon funding can provide substantial cobenefits for aquatic ecosystems, but that the functional integrity of the landscape's myriad small watersheds would be best protected under a more even spatial distribution of forests. Because of its focus on an ecosystem service with global benefits, REDD could access a large pool of global stakeholders willing to pay to maintain carbon in forests, thereby providing a potential cascade of ecosystem services to local stakeholders who would otherwise be unable to afford them.

The El Niño–Southern Oscillation (ENSO) phenomenon is one of the dominant drivers of environmental variability in the tropics. In this study, we examine the connections between ENSO and the climate, ecosystem carbon balance, surface water balance, and river hydrology of the Amazon and Tocantins river basins in South America. First we examine the climatic variability associated with ENSO. We analyze long‐term historical climate records to document the “average” climatic signature of the El Niño and La Niña phases of the ENSO cycle. Generally speaking, the “average El Niño” is drier and warmer than normal in Amazonia, while the “average La Niña” is wetter and cooler. While temperature changes are mostly uniform through the whole year and are spatially homogeneous, precipitation changes are stronger during the wet season (January‐February‐March) and are concentrated in the northern and southeastern portions of the basin. Next we use a land surface/ecosystem model (IBIS), coupled to a hydrological routing algorithm (HYDRA), to examine how ENSO affects land surface water and carbon fluxes, as well as changes in river discharge and flooding. The model results suggest several responses to ENSO: (1) During the average El Niño, there is an anomalous source of CO 2 from terrestrial ecosystems, mainly due to a decreased net primary production (NPP) in the north of the basin. There is also a decrease in river discharge along many of the rivers in the basin, which causes a decrease in flooded area along the main stem of the Amazon. (2) During the average La Niña, there is an anomalous sink of CO 2 into terrestrial ecosystems, largely due to an increase in NPP in the northern portion of the basin. In addition, there is a large increase in river discharge in the Amazon basin, especially from the northern and western tributaries. There is a corresponding increase in flooded area, largely in the northern rivers. These results illustrate that changes in water and carbon balance associated with ENSO have complex, spatially heterogeneous features across the basin. This underscores the need for comprehensive analyses, using long‐term observational data and model simulations, of regional environmental systems and their response to climatic variability.

Abstract This paper describes the impacts of new river geomorphic and flow parameterizations on the simulated surface waters dynamics of the Amazon River basin. Three major improvements to a hydrologic model are presented: (1) the river flow velocity equation is expanded to be dependent on river sinuosity and friction in addition to gradient forces; (2) equations defining the morphological characteristics of the river, such as river height, width and bankfull volume, are derived from 31 622 measurements of river morphology and applied within the model; (3) 1 km resolution topographic data from the Shuttle Radar Topography Mission (SRTM) are used to provide physically based fractional flooding of grid cells from a statistical representation of sub‐grid‐scale floodplain morphology. The discharge and floodplain inundation of the Amazon River is simulated for the period 1968–1998, validated against observations, and compared with results from a previous version of the model. These modifications result in considerable improvement in the simulations of the hydrological features of the Amazon River system. The major impact is that the average wet‐season flooded area on the Amazon mainstem for the period 1983–1988 is now within 5% of satellite‐derived estimates of flooded area, whereas the previous model overestimates the flooded area by about 80%. The improvements are a consequence of the new empirical river geomorphologic functions and the SRTM topography. The new formulation of the flow velocity equation results in increased river velocity on the mainstem and major tributaries and a better correlation between the mean monthly simulated and observed discharge. Copyright © 2007 John Wiley &amp; Sons, Ltd.

A mosaic of protected areas, including indigenous lands, sustainable-use production forests and reserves and strictly protected forests is the cornerstone of conservation in the Amazon, with almost 50 per cent of the region now protected. However, recent research indicates that isolation from direct deforestation or degradation may not be sufficient to maintain the ecological integrity of Amazon forests over the next several decades. Large-scale changes in fire and drought regimes occurring as a result of deforestation and greenhouse gas increases may result in forest degradation, regardless of protected status. How severe or widespread these feedbacks will be is uncertain, but the arc of deforestation in south-southeastern Amazonia appears to be particularly vulnerable owing to high current deforestation rates and ecological sensitivity to climate change. Maintaining forest ecosystem integrity may require significant strengthening of forest conservation on private property, which can in part be accomplished by leveraging existing policy mechanisms.

Fires in tropical forests release globally significant amounts of carbon to the atmosphere and may increase in importance as a result of climate change. Despite the striking impacts of fire on tropical ecosystems, the paucity of robust spatial models of forest fire still hampers our ability to simulate tropical forest fire regimes today and in the future. Here we present a probabilistic model of human-induced fire occurrence for the Amazon that integrates the effects of a series of anthropogenic factors with climatic conditions described by vapor pressure deficit. The model was calibrated using NOAA-12 night satellite hot pixels for 2003 and validated for the years 2002, 2004, and 2005. Assessment of the fire risk map yielded fitness values >85% for all months from 2002 to 2005. Simulated fires exhibited high overlap with NOAA-12 hot pixels regarding both spatial and temporal distributions, showing a spatial fit of 50% within a radius of 11 km and a maximum yearly frequency deviation of 15%. We applied this model to simulate fire regimes in the Amazon until 2050 using IPCC's A2 scenario climate data from the Hadley Centre model and a business-as-usual (BAU) scenario of deforestation and road expansion from SimAmazonia. Results show that the combination of these scenarios may double forest fire occurrence outside protected areas (PAs) in years of extreme drought, expanding the risk of fire even to the northwestern Amazon by midcentury. In particular, forest fires may increase substantially across southern and southwestern Amazon, especially along the highways slated for paving and in agricultural zones. Committed emissions from Amazon forest fires and deforestation under a scenario of global warming and uncurbed deforestation may amount to 21 ± 4 Pg of carbon by 2050. BAU deforestation may increase fires occurrence outside PAs by 19% over the next four decades, while climate change alone may account for a 12% increase. In turn, the combination of climate change and deforestation would boost fire occurrence outside PAs by half during this period. Our modeling results, therefore, confirm the synergy between the two Ds of REDD (Reducing Emissions from Deforestation and Forest Degradation in Developing Countries).

Tropical deforestation changes the surface energy balance and water cycle, but how much change occurs strongly depends on the land uses that follow deforestation. Here, we quantify how recent (2000–2010) transitions among widespread land uses (i.e., forests, croplands, and pastures) altered the water and energy balance in the Xingu region of southeast Amazonia. Spatial-temporal analyses of multiple satellite data sets revealed that forest-to-crop and forest-to-pasture transitions decreased the net surface radiation (by 18% and 12%, respectively) and latent heat flux (32% and 24%), while increasing sensible heat flux (6% and 9%). Land use transitions during the 2000s reduced contemporaneous evapotranspiration (ET) in the Xingu region by 35 km3 and warmed the land surface temperature (LST) by 0.3 °C. Forest-to-pasture and forest-to-crop transitions accounted for most of the observed ET reduction (25.5 km3 and 7 km3, respectively) and LST increase (0.2 °C and 0.07 °C). Pasture-to-crop transitions reduced ET by an additional 2.5 km3 and increased LST by 0.03 °C. If land use had changed at a similar rate within the region’s protected areas, ET would have decreased by another 4.7 km3 and the surface would have warmed an additional 0.5 °C. Forests thus play a key role in regulating regional climate in Amazonia, with protected areas able to attenuate regional climate change caused by land use changes. Our findings show how a major non-GHG forcing, in this case agricultural expansion, has significantly altered regional climate in southeastern Amazonia and how protected forests can mitigate such changes.

Large-scale cattle and crop production are the primary drivers of deforestation in the Amazon today. Such land-use changes can degrade stream ecosystems by reducing connectivity, changing light and nutrient inputs, and altering the quantity and quality of streamwater. This study integrates field data from 12 catchments with satellite-derived information for the 176,000 km(2) upper Xingu watershed (Mato Grosso, Brazil). We quantify recent land-use transitions and evaluate the influence of land management on streamwater temperature, an important determinant of habitat quality in small streams. By 2010, over 40 per cent of catchments outside protected areas were dominated (greater than 60% of area) by agriculture, with an estimated 10,000 impoundments in the upper Xingu. Streams in pasture and soya bean watersheds were significantly warmer than those in forested watersheds, with average daily maxima over 4°C higher in pasture and 3°C higher in soya bean. The upstream density of impoundments and riparian forest cover accounted for 43 per cent of the variation in temperature. Scaling up, our model suggests that management practices associated with recent agricultural expansion may have already increased headwater stream temperatures across the Xingu. Although increased temperatures could negatively impact stream biota, conserving or restoring riparian buffers could reduce predicted warming by as much as fivefold.

Forests, through the regulation of regional water balances, provide a number of ecosystem services, including water for agriculture, hydroelectric power generation, navigation, industry, fisheries, and human consumption. Large-scale deforestation triggers complex non-linear interactions between the atmosphere and biosphere, which may impair such important ecosystem services. This is the case for the Southwestern Amazon, where three important river basins (Juruá, Purus, and Madeira) are undergoing significant land-use changes. Here, we investigate the potential impacts of deforestation throughout the Amazon on the seasonal and annual water balances of these river basins using coupled climatic and hydrologic models under several deforestation scenarios. Simulations without climate response to deforestation show an increase in river discharge proportional to the area deforested in each basin, whereas those with climate response produce progressive reductions in mean annual precipitation over all three basins. In this case, deforestation decreases the mean annual discharge of the Juruá and Purus rivers, but increases that of the Madeira, because the deforestation-induced reduction in evapotranspiration is large enough to increase runoff and thus offset the reduction in precipitation. The effects of Amazon deforestation on river discharge are scale-dependent and vary across and within river basins. Reduction in precipitation due to deforestation is most severe at the end of the dry season. As a result, deforestation increases the dry-season length and the seasonal amplitude of water flow. These effects may aggravate the economic losses from large droughts and floods, such as those experienced in recent years (2005, 2010 and 2009, 2012, respectively).

Abstract There is considerable interest in understanding the fate of the Amazon over the coming century in the face of climate change, rising atmospheric CO 2 levels, ongoing land transformation, and changing fire regimes within the region. In this analysis, we explore the fate of Amazonian ecosystems under the combined impact of these four environmental forcings using three terrestrial biosphere models ( ED 2, IBIS , and JULES ) forced by three bias‐corrected IPCC AR 4 climate projections ( PCM 1, CCSM 3, and Had CM 3) under two land‐use change scenarios. We assess the relative roles of climate change, CO 2 fertilization, land‐use change, and fire in driving the projected changes in Amazonian biomass and forest extent. Our results indicate that the impacts of climate change are primarily determined by the direction and severity of projected changes in regional precipitation: under the driest climate projection, climate change alone is predicted to reduce Amazonian forest cover by an average of 14%. However, the models predict that CO 2 fertilization will enhance vegetation productivity and alleviate climate‐induced increases in plant water stress, and, as a result, sustain high biomass forests, even under the driest climate scenario. Land‐use change and climate‐driven changes in fire frequency are predicted to cause additional aboveground biomass loss and reductions in forest extent. The relative impact of land use and fire dynamics compared to climate and CO 2 impacts varies considerably, depending on both the climate and land‐use scenario, and on the terrestrial biosphere model used, highlighting the importance of improved quantitative understanding of all four factors – climate change, CO 2 fertilization effects, fire, and land use – to the fate of the Amazon over the coming century.

Brazil faces an enormous challenge to implement its revised Forest Code. Despite big losses for the environment, the law introduces new mechanisms to facilitate compliance and foster payment for ecosystem services (PES). The most promising of these is a market for trading forest certificates (CRAs) that allows landowners to offset their restoration obligations by paying for maintaining native vegetation elsewhere. We analyzed the economic potential for the emerging CRA market in Brazil and its implications for PES programs. Results indicate a potential market for trading 4.2 Mha of CRAs with a gross value of US$ 9.2±2.4 billion, with main regional markets forming in the states of Mato Grosso and São Paulo. This would be the largest market for trading forests in the world. Overall, the potential supply of CRAs in Brazilian states exceeds demand, creating an opportunity for additional PES programs to use the CRA market. This expanded market could provide not only monetary incentives to conserve native vegetation, but also environmental co-benefits by fostering PES programs focused on biodiversity, water conservation, and climate regulation. Effective implementation of the Forest Code will be vital to the success of this market and this hurdle brings uncertainty into the market. Long-term commitment, both within Brazil and abroad, will be essential to overcome the many challenges ahead.

Using simplified climate and land-use models, we evaluated primary forests' carbon storage and soybean and pasture productivity in the Brazilian Legal Amazon under several scenarios of deforestation and increased CO2. The four scenarios for the year 2050 that we analyzed consider (1) radiative effects of increased CO2, (2) radiative and physiological effects of increased CO2, (3) effects of land-use changes on the regional climate and (4) radiative and physiological effects of increased CO2 plus land-use climate feedbacks. Under current conditions, means for aboveground forest live biomass (AGB), soybean yield and pasture yield are 179 Mg-C ha−1, 2.7 Mg-grains ha−1 and 16.2 Mg-dry mass ha−1 yr−1, respectively. Our results indicate that expansion of agriculture in Amazonia may be a no-win scenario: in addition to reductions in carbon storage due to deforestation, total agriculture output may either increase much less than proportionally to the potential expansion in agricultural area, or even decrease, as a consequence of climate feedbacks from changes in land use. These climate feedbacks, usually ignored in previous studies, impose a reduction in precipitation that would lead agriculture expansion in Amazonia to become self-defeating: the more agriculture expands, the less productive it becomes.

Deforestation reduced forest cover in Brazil's Xingu River Basin (XB; area: 510,000 km2) from 90% of the basin in the 1970s to 75% in the 2000s. Such large-scale land cover changes can substantially alter regional water budgets, but their influence can be difficult to isolate from that of natural climate variability. In this study, we estimate changes to the XB water balance from the 1970s to the 2000s due to climate variations and deforestation, using a combination of long-term observations of rainfall and discharge; satellite-based estimates of evapotranspiration (MODIS) and surface water storage (GRACE); and numerical modeling estimates (IBIS) of water budget components (evapotranspiration, soil moisture, and discharge). Model simulations over this period suggest that climate variations alone accounted for a −82 mm decrease (mean per unit area) in annual discharge (−14%, from 8190 m3 s−1 to 7806 m3 s−1), due to a −2% decrease in precipitation and +3% increase in evapotranspiration. Deforestation alone caused a +34 mm increase in annual discharge (+6%), as a result of a −3% decrease in evapotranspiration and +1% increase in soil moisture across the XB. Climate variability and land cover change thus had opposite effects on the XB water balance, with climate effects masking deforestation-induced changes to the water budget. Protected areas, which cover 55% of the basin, have helped to mitigate the effects of past deforestation on water recycling in the Xingu. However, our results suggest that continued deforestation outside protected areas could trigger changes of sufficient magnitude to offset climate variability.

The interaction between droughts and land-use fires threaten the carbon stocks, climate regulatory functions, and biodiversity of Amazon forests, particularly in the southeast, where deforestation and land-use ignitions are high. Repeated, severe, or combined fires and droughts result in tropical forest degradation via nonlinear dynamics and may lead to an alternate vegetation state. Here, we discuss the major insights from the longest (more than 10 years) and largest (150-hectare) experimental burn in Amazon forests. Despite initial forest resistance to low-intensity fires, repeated fire during drought killed the majority of trees, reduced canopy cover by half, and favored invasive grasses—but the persistence of this novel vegetation state is unknown. Forest edges, where drying, fire intensity and grass invasion are greatest, were most vulnerable. Crucial to advancing fire ecology in tropical forests, we need to scale these results to understand how flammability and resilience postfire varies across Amazon forest types.

The Amazon forest’s main protection against fire is its capacity to create a moist understory microclimate. Roads, deforestation, droughts, and climate change have made this natural firebreak less effective. The southern Amazon, in particular, has become more flammable and vulnerable to wildfires during recent droughts. The drought of 1997/98 first showed that fires could escape from agricultural fields and burn standing primary forests that were once considered impenetrable to fire. The spread of forest fires during other 21st-century droughts suggests that this pattern may well be the new normal. With the landscape becoming more flammable, reducing sources of ignition and the negative effects of deforestation is crucial for avoiding severe degradation of Amazon forests. Unfortunately, recent increases in deforestation suggest that Brazil is moving in the opposite direction. Keeping pace with the rapid changes in the region’s fire regimes would require innovation; cooperation across political boundaries; and interagency communication on a scale never seen before. While Brazil’s past success in reducing deforestation suggests that it could be an effective leader in this regard, its sluggish response to the 2019 fires tells quite a different story. But the fact remains that the future of the Amazon depends on decisive action now.

The Brazilian Cerrado is one of the most biodiverse savannas in the world, yet 46% of its original cover has been cleared to make way for crops and pastures. These extensive land-use transitions (LUTs) are expected to influence regional climate by reducing evapotranspiration (ET), increasing land surface temperature (LST), and ultimately reducing precipitation. Here, we quantify the impacts of LUTs on ET and LST in the Cerrado by combining MODIS satellite data with annual land use and land cover maps from 2006 to 2019. We performed regression analyses to quantify the effects of six common LUTs on ET and LST across the entire gradient of Cerrado landscapes. Results indicate that clearing forests for cropland or pasture increased average LST by ~3.5°C and reduced mean annual ET by 44% and 39%, respectively. Transitions from woody savannas to cropland or pasture increased average LST by 1.9°C and reduced mean annual ET by 27% and 21%, respectively. Converting native grasslands to cropland or pasture increased average LST by 0.9 and 0.6°C, respectively. Conversely, grassland-to-pasture transitions increased mean annual ET by 15%. To date, land changes have caused a 10% reduction in water recycled to the atmosphere annually and a 0.9°C increase in average LST across the biome, compared to the historic baseline under native vegetation. Global climate changes from increased atmospheric greenhouse gas concentrations will only exacerbate these effects. Considering potential future scenarios, we found that abandoning deforestation control policies or allowing legal deforestation to continue (at least 28.4 Mha) would further reduce yearly ET (by -9% and -3%, respectively) and increase average LST (by +0.7 and +0.3°C, respectively) by 2050. In contrast, policies encouraging zero deforestation and restoration of the 5.2 Mha of illegally deforested areas would partially offset the warming and drying impacts of land-use change.O Cerrado brasileiro é uma das savanas mais biodiversas do mundo. Apesar disso, 46% da sua cobertura original foi desmatada para dar lugar a cultivos agrícolas e pastos. Estas extensas transições de uso do solo (LUT) têm o potencial de influenciar o clima regional, reduzindo a evapotranspiração (ET), aumentando a temperatura da superfície terrestre (LST) e por fim reduzindo a precipitação. O objetivo deste estudo foi quantificar os impactos de LUTs sobre ET e LST no Cerrado, combinando dados do satélite MODIS com mapas anuais de uso e cobertura do solo de 2006-2019. Foram realizadas análises de regressão para quantificar os efeitos de seis LUTs usuais sobre ET e LST, ao longo de todo o gradiente de paisagens do Cerrado. Os resultados indicaram que a retirada de florestas para dar lugar à agricultura ou pastagem aumentou a LST média em ~3.5°C e reduziu a ET média anual em 44% e 39%, respectivamente. Transições de formações savânicas para agricultura ou pastagem aumentaram a LST média em 1.9°C e reduziram a ET média anual em 27% e 21%, respectivamente. A conversão de campos nativos para agricultura ou pastagem aumentou a LST média em 0.9 e 0.6°C, respectivamente. Em contrapartida, transições de formações campestres nativas para pastagens aumentaram a ET média anual em 15%. Até o momento, as mudanças de uso do solo causaram redução de 10% da água reciclada para a atmosfera anualmente e aumento de 0.9°C da LST média ao longo do bioma, em comparação com a linha de base histórica sob vegetação nativa. As mudanças climáticas globais decorrentes do aumento das concentrações atmosféricas de gases do efeito estufa irão exacerbar esses efeitos. Considerando potenciais cenários futuros, observou-se que o abandono das políticas de controle do desmatamento ou o avanço do desmatamento legal (ao menos 28.4 Mha) reduziriam a ET anual (em −9% e −3%, respectivamente) e aumentariam a LST média (em +0.7 e +0.3ºC, respectivamente) até 2050. Por outro lado, políticas que promovam desmatamento zero e restauração dos 5.2 Mha de áreas ilegalmente desmatadas compensariam parte dos impactos de aquecimento e seca causados por alterações de uso do solo.

A global hydrological routing algorithm (HYDRA) that simulates seasonal river discharge and changes in surface water level on a spatial resolution of 5′ long × 5′ lat is presented. The model is based on previous work by M. T. Coe and incorporates major improvements from that work including 1) the ability to simulate monthly and seasonal variations in discharge and lake and wetland level, and 2) direct representation of man-made dams and reservoirs. HYDRA requires as input daily or monthly mean averages of runoff, precipitation, and evaporation either from GCM output or observations. As an example of the utility of HYDRA in evaluating GCM simulations, the model is forced with monthly mean estimates of runoff from the National Centers for Environmental Prediction (NCEP) reanalysis dataset. The simulated river discharge clearly shows that although the NCEP runoff captures the large-scale features of the observed terrestrial hydrology, there are numerous differences in detail from observations. The simulated mean annual discharge is within ±20% at only 13 of 90 fluvial gauging stations compared. In general, the discharge is overestimated for most of the northern high latitudes, midcontinental North America, eastern Europe, central and eastern Asia, India, and northern Africa. Only in western Europe and eastern North America is the discharge consistently underestimated. Although there appears to be a need for improved simulation of land surface physics in the NCEP product and parameterization of flow velocities within HYDRA, the timing of the monthly mean discharge is in fair agreement with the observations. Including lakes within HYDRA reduces the amplitude of the seasonal cycle of discharge and the magnitude of the annual mean discharge of the St. Lawrence River system, in qualitative agreement with the observations. In addition, including the wetlands of the Sudd reduces the magnitude of the simulated annual discharge of the Nile River to values in better agreement with observations. Finally, the impact of man-made dams and their reservoirs on the magnitude of monthly mean discharge can be explicitly included within HYDRA. As an example, including dams and reservoirs on the Parana River improves the agreement of the simulated mean monthly discharge with observations by reducing the amplitude of the seasonal cycle to values in good agreement with the observations. The results of this study show that, although improvements can be obtained through better representations of flow velocities and more accurate digital elevation models, HYDRA can be a powerful tool for diagnosing simulated terrestrial hydrology and investigations of global climate change.

Alcohol expectancies are important in the mediation and prediction of alcohol use. Expectancies for the effects of other drugs, although less well delineated, appear equally important. Therefore, development and validation of expectancy measures for drugs other than alcohol is necessary for evaluating the importance of these constructs. We examined the factor structure, reliability, and validity of the Marijuana Effect Expectancy Questionnaire (MEEQ) and the Stimulant Effect Expectancy Questionnaire (SEEQ) in clinical and community samples of adolescents as they moved into young adulthood (N=279). Confirmatory factor analyses (CFAs) supported the a priori factors, and we found good reliability for most individual scales. Temporal stability and convergent and discriminant validity of drug effect expectancies were supported in this sample of adolescents and young adults. Drug effect expectancies were associated with drug preference and drug use patterns over 2 years. Use of these measures may aid our understanding of the etiology and course of marijuana and stimulant involvement during adolescence and young adulthood.

We ran a sequence of climate model experiments for 6000 years ago, with land‐surface conditions based on a realistic map of palaeovegetation, lakes and wetlands, to quantify the effects of land‐surface feedbacks in the Saharan region. Vegetation‐induced albedo and moisture flux changes produced year‐round warming, forced the monsoon to 17°–25°N two months earlier, and shifted the precipitation belt ≈300 km northwards compared to the effects of orbital forcing alone. The addition of lakes and wetlands produced localised changes in evaporation and precipitation, but caused no further extension of the monsoon belt. Diagnostic analyses with biome and continental hydrology models showed that the combined land‐surface feedbacks, although substantial, could neither maintain grassland as far north as observed (≈26°N) nor maintain Lake “MegaChad” (330,000 km²).

The export of nitrate by the Mississippi River to the Gulf of Mexico has tripled since the 1950s primarily due to an increase in agricultural fertilizer application and hydrological changes. Here we have adapted two physically based models, the Integrated Biosphere Simulator (IBIS) terrestrial ecosystem model and the Hydrological Routing Algorithm (HYDRA) hydrological transport model, to simulate the nitrate export in the Mississippi River system and isolate the role of hydrological processes in the observed increase and interannual variability in nitrate export. Using an empirical nitrate input algorithm based on constant land cover and variability in runoff, the modeling system is able to represent much of the spatial and interannual variability in aquatic nitrate export. The results indicate that about a quarter of the sharp increase in nitrate export from 1966 to 1994 was due to an increase in runoff across the basin. This illustrates the pivotal role of hydrology and climate in the balance between storage of nitrate in the terrestrial system and leaching.

A terrain‐based hydrologic model is developed to simulate rivers, lakes, and wetlands on the continental scale as a linked dynamical system. This surface water area model (SWAM) is an extension of earlier work [ Coe , 1997] and is based on a linear reservoir model. The model requires, as input, estimates of runoff, precipitation, and evaporation from either observations or climate simulations. The model develops its own river transport directions based on elevation. The river discharge is calculated at each grid cell as the accumulated flow of water across the land surface. Lake and wetland area and volume are calculated as a function of the local precipitation minus evaporation, the streamflow into and out of the grid cells, and the potential for storage of water on the surface as derived from 5′ × 5′ resolution digital terrain models. SWAM is applied on a 5′ × 5′ spatial resolution to simulate present‐day surface waters and river transport for all continents (except Antarctica and Greenland). The model simulates the discharge of the 27 major rivers of the world in fair agreement with the observations; 12 of the rivers have simulated discharge within ±20% of the observational estimates. The discharge from rivers in arid and semi‐arid climates is generally overestimated probably due to underestimated evaporation from wetlands, irrigated croplands, and reservoirs within the river basins. The modern simulated lake area (about 3% of the land area) is larger than the observed area (about 2% of the land area). Wetlands are poorly simulated by the model due to the coarse vertical and horizontal resolution of the digital terrain models. The model simulates the potential for increased surface water (up to 7.5% of the global land area) and river basin area in semi‐arid and arid regions where closed basins exist in the present day climate which illustrates the utility of SWAM for climate change experiments. While higher resolution and more accurate digital terrain models are needed to improve these surface water simulations (particularly for wetlands), these preliminary results indicate that current digital terrain models are adequate for including lakes and rivers as interactive components in the surface hydrology parameterizations of climate models and for studying feedbacks between lakes and climate.

The application of satellite radar altimetry to the determination of lake and river elevations has been used in numerous projects, and is well validated. Here we show that with the aid of ground‐based information, this technique can be extended to determine river discharge and predict downstream lake and marsh height. The Lake Chad basin provides an ideal case study due to its well‐known hydrology and complex lake and marsh morphology and because prediction of lake and marsh height has been identified as potentially useful to people living in the region. Altimetric stage measurements from the TOPEX/Poseidon satellite, at the Chari/Ouham confluence, estimate river discharge about 500 km downstream at N'Djamena 10 days in advance ( r 2 = 0.9562). Via simple linear correlation methods, the stage measurements successfully estimate the height of the permanent waters of the lake (600 km downstream) 39 days in advance ( r 2 = 0.9297). Predicting the water height on the western marshes of the lake bed is poorer ( r 2 = 0.7958) due to a change in response time of the local stage to the seasonal floods coincident with an observed increase in mean water level in the latter half of the 1990s. Before 1997 a 96‐day phase lag results in the best fit ( r 2 = 0.6463). After 1997 the best fit is obtained with a 66‐day phase lag ( r 2 = 0.8139). The excellent river discharge and lake height predictions show that altimetry is a useful tool where ground‐based data are difficult to obtain and where rapid water resource assessment is desirable.

To examine the relationship of adolescent alcohol and drug use over a 5-year period to cumulative health problems in late adolescence and young adulthood.We prospectively examined self-reported health problems in a sample of adolescents, some of whom received treatment for substance use disorders and had consistently poor substance use outcomes (n = 38), some of whom received treatment for substance use disorders and had positive substance use outcomes (n = 30), and a low alcohol and drug use community comparison group (n = 48). Data regarding health-related problems of these adolescents (mean, 15.9 years; 83% Caucasian; 56.5% female) were collected at 2, 4, and 6 years following initial assessments.Alcohol and/or drug involvement severe enough to warrant treatment during adolescence was associated with more cumulative health problems and severe health problems for girls and more cumulative health problems for boys. Protracted and continuous abuse of alcohol and drugs was associated with more cumulative and severe health problems for girls and more severe health problems for boys.These results suggest that significant health problems and concerns are related to both brief and protracted alcohol and drug abuse during adolescence. Health problems will likely become even more evident as early-onset, chronic substance abusers continue to age.

Summary 1. Lakes are a prominent feature of the Northern Highland Lake District (NHLD) of Wisconsin, covering 13% of the landscape. Summarising the physical, chemical, or biological nature of NHLD lakes at a regional scale requires a representative sample of the full size distributions of lakes. In this study, we selected at random 168 lakes from the full size distribution of lakes in the NHLD and sampled each lake for a broad suite of limnological variables. 2. Most lakes were small. The median lake area was 1.1 ha, however, half of the surface area of water was in a relatively small number of lakes larger than 162 ha. Smaller lakes tended to be low in dissolved inorganic carbon (DIC) and high in dissolved organic carbon (DOC). Inclusion of small lakes (&lt;4 ha) in the survey resulted in an acid neutralising capacity (ANC) median (76.5 μ Eq L −1 ) much lower than previous estimates, and a DOC median (10.1 mg L −1 ) about 50% higher than it would have been without the smaller lakes. Unlike DOC, total P tended to be evenly distributed across lake sizes. 3. The implications of these findings are that regional summaries of lake characteristics for the NHLD are influenced by the inclusion of small lakes in the sample, even though most of the water surface area is in lakes larger than 162 ha. Excluding small lakes introduces bias in the estimates of organic carbon and inorganic carbon values, for example. Similar biases may be introduced for lake characteristics at the global scale if small lakes are not sampled, because the size distribution of lakes globally is dominated in number by small lakes.

Global Change BiologyVolume 17, Issue 5 p. 1821-1833 Conversion to soy on the Amazonian agricultural frontier increases streamflow without affecting stormflow dynamics SHELBY J. HAYHOE, SHELBY J. HAYHOE Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543, USASearch for more papers by this authorCHRISTOPHER NEILL, CHRISTOPHER NEILL Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543, USASearch for more papers by this authorSTEPHEN PORDER, STEPHEN PORDER Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USASearch for more papers by this authorRICHARD MCHORNEY, RICHARD MCHORNEY The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543, USASearch for more papers by this authorPAUL LEFEBVRE, PAUL LEFEBVRE The Woods Hole Research Center, 149 Woods Hole Road, Falmouth, MA 02540, USASearch for more papers by this authorMICHAEL T. COE, MICHAEL T. COE The Woods Hole Research Center, 149 Woods Hole Road, Falmouth, MA 02540, USASearch for more papers by this authorHELMUT ELSENBEER, HELMUT ELSENBEER Institut für Erd- und Umweltwissenschaften, Universität Potsdam, Potsdam, GermanySearch for more papers by this authorALEX V. KRUSCHE, ALEX V. KRUSCHE Laboratório de Ecologia Isotópica, Centro de Energia na Agricultura, University of São Paulo, Piracicaba, SP, BrazilSearch for more papers by this author SHELBY J. HAYHOE, SHELBY J. HAYHOE Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543, USASearch for more papers by this authorCHRISTOPHER NEILL, CHRISTOPHER NEILL Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543, USASearch for more papers by this authorSTEPHEN PORDER, STEPHEN PORDER Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USASearch for more papers by this authorRICHARD MCHORNEY, RICHARD MCHORNEY The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543, USASearch for more papers by this authorPAUL LEFEBVRE, PAUL LEFEBVRE The Woods Hole Research Center, 149 Woods Hole Road, Falmouth, MA 02540, USASearch for more papers by this authorMICHAEL T. COE, MICHAEL T. COE The Woods Hole Research Center, 149 Woods Hole Road, Falmouth, MA 02540, USASearch for more papers by this authorHELMUT ELSENBEER, HELMUT ELSENBEER Institut für Erd- und Umweltwissenschaften, Universität Potsdam, Potsdam, GermanySearch for more papers by this authorALEX V. KRUSCHE, ALEX V. KRUSCHE Laboratório de Ecologia Isotópica, Centro de Energia na Agricultura, University of São Paulo, Piracicaba, SP, BrazilSearch for more papers by this author First published: 25 January 2011 https://doi.org/10.1111/j.1365-2486.2011.02392.xCitations: 84 Shelby Hayhoe, Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA, e-mail: [email protected] Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Abstract Large-scale soy agriculture in the southern Brazilian Amazon now rivals deforestation for pasture as the region's predominant form of land use change. Such landscape-level change can have substantial consequences for local and regional hydrology, but these effects remain relatively unstudied in this ecologically and economically important region. We examined how the conversion to soy agriculture influences water balances and stormflows using stream discharge (water yields) and the timing of discharge (stream hydrographs) in small (2.5–13.5 km2) forested and soy headwater watersheds in the Upper Xingu Watershed in the state of Mato Grosso, Brazil. We monitored water yield for 1 year in three forested and four soy watersheds. Mean daily water yields were approximately four times higher in soy than forested watersheds, and soy watersheds showed greater seasonal variability in discharge. 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The papers in this special issue address a major challenge facing our society: feeding a population that is simultaneously growing and increasing its per capita food consumption, while preventing widespread ecological and social impoverishment in the tropics. By focusing mostly on the Amazon's most dynamic agricultural frontier, Mato Grosso, they collectively clarify some key elements of achieving more sustainable agriculture. First, stakeholders in commodity-driven agricultural Amazonian frontiers respond rapidly to multiple forces, including global markets, international pressures for sustainably produced commodities and national-, state- and municipality-level policies. These forces can encourage or discourage deforestation rate changes within a short time-period. Second, agricultural frontiers are linked systems, land-use change is linked with regional climate, forest fires, water quality and stream discharge, which in turn are linked with the well-being of human populations. Thus, land-use practices at the farm level have ecological and social repercussions far removed from it. Third, policies need to consider the full socio-economic system to identify the efficacy and consequences of possible land management strategies. Monitoring to devise suitable management approaches depends not only on tracking land-use change, but also on monitoring the regional ecological and social consequences. Mato Grosso's achievements in reducing deforestation are impressive, yet they are also fragile. The ecological and social consequences and the successes and failures of management in this region can serve as an example of possible trajectories for other commodity-driven tropical agricultural frontiers.

We investigate the potential for closing the water balance purely from remote sensing (RS) sources and quantify the hydrological dynamic of the Pantanal (Brazil), the world's largest continuous wetland. We use 10-year time series of total water storage changes (ΔS) derived from GRACE and the balance between precipitation (P) derived from TRMM and evapotranspiration (ET) derived from MOD16, as well as the overall vegetation response (EVI2) to water availability. The GRACE-estimates of total water storage were consistent with in situ measurements from the Ladário gauge station. Despite the coarse spatial resolution of GRACE, its estimates were able not only to represent the hydrological regime of the entire basin but also its internal variability. The total water storage change estimates correlated well with precipitation (r = 0.87), evapotranspiration (r = 0.83), and vegetation greenness (r = 0.85), particularly when a two to three month time lag was considered. Likewise, the MODIS-derived vegetation greenness was consistent with variations in precipitation (r = 0.77) and evapotranspiration (r = 0.79). Nevertheless, we found that the water balance could not be closed with these data. Inferred runoff was greatly overestimated due mainly to an underestimation of ET. The uncertainty in the inputs and scarce validation data were limiting factors.

The expansion and intensification of soya bean agriculture in southeastern Amazonia can alter watershed hydrology and biogeochemistry by changing the land cover, water balance and nutrient inputs. Several new insights on the responses of watershed hydrology and biogeochemistry to deforestation in Mato Grosso have emerged from recent intensive field campaigns in this region. Because of reduced evapotranspiration, total water export increases threefold to fourfold in soya bean watersheds compared with forest. However, the deep and highly permeable soils on the broad plateaus on which much of the soya bean cultivation has expanded buffer small soya bean watersheds against increased stormflows. Concentrations of nitrate and phosphate do not differ between forest or soya bean watersheds because fixation of phosphorus fertilizer by iron and aluminium oxides and anion exchange of nitrate in deep soils restrict nutrient movement. Despite resistance to biogeochemical change, streams in soya bean watersheds have higher temperatures caused by impoundments and reduction of bordering riparian forest. In larger rivers, increased water flow, current velocities and sediment flux following deforestation can reshape stream morphology, suggesting that cumulative impacts of deforestation in small watersheds will occur at larger scales.

The Brazilian savanna (known as Cerrado) is an upland biome made up of various vegetation types from herbaceous to arboreal. In this paper, MODIS remote sensing vegetation greenness from the Enhanced Vegetation Index (EVI) and evapotranspiration (ET) data for the 2000–2012 period were analyzed to understand the differences in the net primary productivity (NPP-proxy), carbon, and the evaporative flux of the major Cerrado natural and anthropic landscapes. The understanding of the carbon and evaporative fluxes of the main natural and anthropic vegetation types is of fundamental importance in studies regarding the impacts of land cover and land use changes in the regional and global climate. The seasonal dynamics of EVI and ET of the main natural and anthropic vegetation types of the Cerrado biome were analyzed using a total of 35 satellite-based samples distributed over representative Cerrado landscapes. Carbon and water fluxes were estimated for different scenarios, such as, a hypothetical unconverted Cerrado, 2002 and 2050 scenarios based on values derived from literature and on the PROBIO land cover and land use map for the Cerrado. The total growing season biomass for 2002 in the Cerrado region was estimated to be 28 gigatons of carbon and the evapotranspiration was 1336 gigatons of water. The mean estimated growing season evapotranspiration and biomass for 2002 was 576 Gt of water and 12 Gt of carbon for pasture and croplands compared to 760 Gt of water and 15 Gt of carbon for the Cerrado natural vegetation. In a modeled future scenario for the year 2050, the ET flux from natural Cerrado vegetation was 394 Gt less than in 2002 and 991 Gt less than in an unconverted scenario, with only natural vegetation, while the carbon was 8 Gt less than in 2002 and 21 Gt less than in this hypothetical pre-conversion Cerrado. On the other hand, the sum of the pasture and cropland ET flux increased by 405 Gt in 2050 relative to 2002 and the carbon by 11 Gt of carbon. Given the increasing global demand for agricultural products and the insufficient protected areas in the Cerrado (with a significant area of remaining native vegetation in privately owned lands that may be legally deforested), our analyses suggest that potential future changes to the water and carbon balances are likely to be highly significant in the severely threatened Cerrado biome. On the other hand, our results also suggest that the recovery of degraded pastures can have a positive impact on climate, due to the higher rates of carbon sequestration and water transfer to the atmosphere.

Amazon droughts directly increase forest flammability by reducing forest understory air and fuel moisture. Droughts also increase forest flammability indirectly by decreasing soil moisture, triggering leaf shedding, branch loss, and tree mortality—all of which contribute to increased fuel loads. These direct and indirect effects can cause widespread forest fires that reduce forest carbon stocks in the Amazon, with potentially important consequences for the global carbon cycle. These processes are expected to become more widespread, common, and intense as global climate changes, yet the mechanisms linking droughts, wildfires, and associated changes in carbon stocks remain poorly understood. Here, we expanded the capabilities of a dynamic forest carbon model to better represent (1) drought effects on carbon and fuel dynamics and (2) understory fire behavior and severity. We used the refined model to quantify changes in Pan-Amazon live carbon stocks as a function of the maximum climatological water deficit (MCWD) and fire intensity, under both historical and future climate conditions. We found that the 2005 and 2010 droughts increased potential fire intensity by 226 kW m−1 and 494 kW m−1, respectively. These increases were due primarily to increased understory dryness (109 kW m−1 in 2005; 124 kW m−1 in 2010) and altered forest structure (117 kW m−1 in 2005; 370 kW m−1 in 2010) effects. Combined, these historic droughts drove total simulated reductions in live carbon stocks of 0.016 (2005) and 0.027 (2010) PgC across the Amazon Basin. Projected increases in future fire intensity increased simulated carbon losses by up to 90% per unit area burned, compared with modern climate. Increased air temperature was the primary driver of changes in simulated future fire intensity, while reduced precipitation was secondary, particularly in the eastern portion of the Basin. Our results show that fire-drought interactions strongly affect live carbon stocks and that future climate change, combined with the synergistic effects of drought on forest flammability, may strongly influence the stability of tropical forests in the future.

Abstract Agricultural intensification offers potential to grow more food while reducing the conversion of native ecosystems to croplands. However, intensification also risks environmental degradation through emissions of the greenhouse gas nitrous oxide (N 2 O) and nitrate leaching to ground and surface waters. Intensively-managed croplands and nitrogen (N) fertilizer use are expanding rapidly in tropical regions. We quantified fertilizer responses of maize yield, N 2 O emissions, and N leaching in an Amazon soybean-maize double-cropping system on deep, highly-weathered soils in Mato Grosso, Brazil. Application of N fertilizer above 80 kg N ha −1 yr −1 increased maize yield and N 2 O emissions only slightly. Unlike experiences in temperate regions, leached nitrate accumulated in deep soils with increased fertilizer and conversion to cropping at N fertilization rates &gt;80 kg N ha −1 , which exceeded maize demand. This raises new questions about the capacity of tropical agricultural soils to store nitrogen, which may determine when and how much nitrogen impacts surface waters.

The role of tropical forests in climate is most often expressed in terms of the carbon they keep out of the atmosphere if deforestation is avoided or the carbon they remove from the atmosphere as they grow. The direct role of forests, particularly in the tropics, in maintaining low surface temperatures and relatively high precipitation has been underappreciated. Recent studies in the Brazilian agricultural frontier indicate that tropical deforestation, for pasture and crop production, has led to significant regional climate change in the last 40 years of a scale much larger than that attributed to the carbon released from deforestation. Deforestation reduces net surface radiation and evapotranspiration, thus increasing sensible heat flux and land surface temperature. In Mato Grosso state, the temperature of the forested Xingu Indigenous Park is 3℃ cooler than the surrounding mosaic of pasturelands, croplands, and remaining forest fragments. In the neighboring state of Rondônia, rainfall has significantly decreased and the dry season lengthened as deforestation occurred. Numerical model studies strongly suggest that Brazil’s agricultural frontier will be much warmer and dryer in coming decades as greenhouse gas concentrations increase. Thus, in Brazil, it is becoming clear that, because of their capacity to moderate regional climate, preserving tropical forests will be a key component of mitigating exogenously driven future climate change.

Drought, fire, and windstorms can interact to degrade tropical forests and the ecosystem services they provide, but how these forests recover after catastrophic disturbance events remains relatively unknown. Here, we analyze multi-year measurements of vegetation dynamics and function (fluxes of CO2 and H2 O) in forests recovering from 7 years of controlled burns, followed by wind disturbance. Located in southeast Amazonia, the experimental forest consists of three 50-ha plots burned annually, triennially, or not at all from 2004 to 2010. During the subsequent 6-year recovery period, postfire tree survivorship and biomass sharply declined, with aboveground C stocks decreasing by 70%-94% along forest edges (0-200 m into the forest) and 36%-40% in the forest interior. Vegetation regrowth in the forest understory triggered partial canopy closure (70%-80%) from 2010 to 2015. The composition and spatial distribution of grasses invading degraded forest evolved rapidly, likely because of the delayed mortality. Four years after the experimental fires ended (2014), the burned plots assimilated 36% less carbon than the Control, but net CO2 exchange and evapotranspiration (ET) had fully recovered 7 years after the experimental fires ended (2017). Carbon uptake recovery occurred largely in response to increased light-use efficiency and reduced postfire respiration, whereas increased water use associated with postfire growth of new recruits and remaining trees explained the recovery in ET. Although the effects of interacting disturbances (e.g., fires, forest fragmentation, and blowdown events) on mortality and biomass persist over many years, the rapid recovery of carbon and water fluxes can help stabilize local climate.

Abstract The amplitude, duration, frequency, and predictability of runoff and inundation of aquatic habitats are key hydrological characteristics linked to aquatic ecosystem functioning and biodiversity, but they are seldom integrated into analyses of Amazon floodplain ecology. Remote sensing approaches, measurements and modelling of floodplain hydrology provide a basis for this integration. Effective legislation to protect floodplains and other wetlands depends on operational definitions that require application of hydrological data. Extent and changes of flooded areas are linked to fish diversity and to presence and growth of flooded forests and floating plants. Dam construction reduces river system connectivity and modifies the flood pulse, with major negative implications for floodplain ecosystems adapted to and dependent on a natural flood regime. Trends and variability in climate plus deforestation are altering the Amazon's hydrological cycle, causing changes in discharge and flooded area with concomitant ecological impacts.

The Amazon River basin harbors some of the world's largest wetland complexes, which are of major importance for biodiversity, the water cycle and climate, and human activities. Accurate estimates of inundation extent and its variations across spatial and temporal scales are therefore fundamental to understand and manage the basin's resources. More than fifty inundation estimates have been generated for this region, yet major differences exist among the datasets, and a comprehensive assessment of them is lacking. Here we present an intercomparison of 29 inundation datasets for the Amazon basin, based on remote sensing only, hydrological modeling, or multi-source datasets, with 18 covering the lowland Amazon basin (elevation <500 m, which includes most Amazon wetlands), and 11 covering individual wetland complexes (subregional datasets). Spatial resolutions range from 12.5 m to 25 km, and temporal resolution from static to monthly, spanning up to a few decades. Overall, 31% of the lowland basin is estimated as subject to inundation by at least one dataset. The long-term maximum inundated area across the lowland basin is estimated at 599,700 ± 81,800 km2 if considering the three higher quality SAR-based datasets, and 490,300 ± 204,800 km2 if considering all 18 datasets. However, even the highest resolution SAR-based dataset underestimates the maximum values for individual wetland complexes, suggesting a basin-scale underestimation of ~10%. The minimum inundation extent shows greater disagreements among datasets than the maximum extent: 139,300 ± 127,800 km2 for SAR-based ones and 112,392 ± 79,300 km2 for all datasets. Discrepancies arise from differences among sensors, time periods, dates of acquisition, spatial resolution, and data processing algorithms. The median total area subject to inundation in medium to large river floodplains (drainage area > 1000 km2) is 323,700 km2. The highest spatial agreement is observed for floodplains dominated by open water such as along the lower Amazon River, whereas intermediate agreement is found along major vegetated floodplains fringing larger rivers (e.g., Amazon mainstem floodplain). Especially large disagreements exist among estimates for interfluvial wetlands (Llanos de Moxos, Pacaya-Samiria, Negro, Roraima), where inundation tends to be shallower and more variable in time. Our data intercomparison helps identify the current major knowledge gaps regarding inundation mapping in the Amazon and their implications for multiple applications. In the context of forthcoming hydrology-oriented satellite missions, we make recommendations for future developments of inundation estimates in the Amazon and present a WebGIS application (https://amazon-inundation.herokuapp.com/) we developed to provide user-friendly visualization and data acquisition of current Amazon inundation datasets.

A terrestrial ecosystem model (integrated biosphere simulator (IBIS)) and a hydrological routing algorithm (HYDRA) are used in conjunction with long time series climate data to simulate the river discharge and flooded area of the Amazon/Tocantins River basin over the last 60 years. Evaluating the results of this modeling exercise over the entire basin yields three major results: (1) Observations at 121 stations throughout the basin show that discharge is well simulated for most tributaries originating in Brazil. However, the discharge is consistently underestimated, by greater than 20%, for tributaries draining regions outside of Brazil and the main stem of the Amazon. The discharge underestimation is most likely a result of underestimated precipitation in the data set used as model input. (2) A new flooding algorithm within HYDRA captures the magnitude and timing of the river height and flooded area in relatively good agreement with observations, particularly downstream of the confluence of the Negro and Solimões Rivers. (3) Climatic variability strongly impacts the hydrology of the basin. Specifically, we find that short (∼3–4 years) and long (∼28 years) modes of precipitation variability drive spatial and temporal variability in river discharge and flooded area throughout the Amazon/Tocantins River basins.

Observations indicate that the area of lakes and wetlands in northern Africa was considerably greater during the middle Holocene than at present. Simulations are designed to examine whether expanded surface waters may have had a significant impact on the strength of the summer monsoon of northern Africa. Three experiments with the National Center for Atmospheric Research community climate model (NCAR CCM3) are analyzed, a modern and two middle Holocene (6000 years before present) simulations, one with and one without prescribed expanded surface water. There is a significant increase in the strength of the summer monsoon in the middle Holocene simulation due to the enhanced seasonal insolation cycle. The addition of surface waters result in a June, July, and August mean increase in the net surface radiation (5%), an increase in the latent heat flux (30%), a decrease in the sensible heat flux (10%), and an increase in the near‐surface specific humidity (&gt;5%) compared to the middle Holocene simulation without surface water changes. The changes in these simulated climate variables are comparable in scale to changes due to orbital forcing alone. The expanded surface waters result in a cooling of the atmosphere and anticyclonic flow over the large water bodies in summer relative to the simulation without surface water changes. The combination of increased atmospheric moisture and altered circulation results in significant changes to the precipitation distribution in northern Africa including a small increase in the zonal mean July precipitation to the north of the lakes and a decrease to the south. The geographic distribution of the precipitation with surface water changes is qualitatively in better agreement with observations than the distribution with orbital forcing alone but still does not fully match the expansion implied by observations nor the expansion required to produce the simulated middle Holocene surface waters used in this study. The results of this study suggest that surface waters were an important factor in the climate of northern Africa during the middle and early Holocene and that they must be included for accurate simulation of this climate.

Abstract. Dynamic vegetation models forced with spatially homogeneous biophysical parameters are capable of producing average productivity and biomass values for the Amazon basin forest biome that are close to the observed estimates, but these models are unable to reproduce observed spatial variability. Recent observational studies have shown substantial regional spatial variability of above-ground productivity and biomass across the Amazon basin, which is believed to be primarily driven by a combination of soil physical and chemical properties. In this study, spatial heterogeneity of vegetation properties is added to the Integrated Biosphere Simulator (IBIS) land surface model, and the simulated productivity and biomass of the Amazon basin are compared to observations from undisturbed forest. The maximum RuBiCo carboxylation capacity (Vcmax) and the woody biomass residence time (τw) were found to be the most important properties determining the modeled spatial variation of above-ground woody net primary productivity and biomass, respectively. Spatial heterogeneity of these properties may lead to simulated spatial variability of 1.8 times in the woody net primary productivity (NPPw) and 2.8 times in the woody above-ground biomass (AGBw). The coefficient of correlation between the modeled and observed woody productivity improved from 0.10 with homogeneous parameters to 0.73 with spatially heterogeneous parameters, while the coefficient of correlation between the simulated and observed woody above-ground biomass improved from 0.33 to 0.88. The results from our analyses with the IBIS dynamic vegetation model demonstrated that using single values for key ecological parameters in the tropical forest biome severely limits simulation accuracy. Clearer understanding of the biophysical mechanisms that drive the spatial variability of carbon allocation, τw and Vcmax is necessary to achieve further improvements to simulation accuracy.

Abstract. The Amazon Basin is a region of global importance for the carbon and hydrological cycles, a biodiversity hotspot, and a potential centre for future economic development. The region is also a major source of water vapour recycled into continental precipitation through evapotranspiration processes. This review applies an ecohydrological approach to Amazonia's water cycle by looking at contributions of water resources in the context of future agricultural production. At present, agriculture in the region is primarily rain-fed and relies almost exclusively on green-water resources (soil moisture regenerated by precipitation). Future agricultural development, however, will likely follow pathways that include irrigation from blue-water sources (surface water and groundwater) as insurance from variability in precipitation. In this review, we first provide an updated summary of the green–blue ecohydrological framework before describing past trends in Amazonia's water resources within the context of land use and land cover change. We then describe green- and blue-water trade-offs in light of future agricultural production and potential irrigation to assess costs and benefits to terrestrial ecosystems, particularly land and biodiversity protection, and regional precipitation recycling. Management of green water is needed, particularly at the agricultural frontier located in the headwaters of major tributaries to the Amazon River, and home to key downstream blue-water users and ecosystem services, including domestic and industrial users, as well as aquatic ecosystems.

The study compared the perceptions of nurses who participated in the clinical education of students using traditional and dedicated education unit (DEU) models.In the traditional model, faculty are the primary clinical instructors for students. In a DEU, nurses provide clinical instruction with faculty support.This mixed-methods study used surveys and interviews.Compared to nurses on traditional units, DEU nurses were more likely to agree that their unit welcomed students, had a strong commitment to teaching, and received professional development from clinical faculty. The nurses rated the learning gains of students as greater on DEUs than traditional units and viewed the leadership of the nurse manager and the quality of patient care as similar.The study provides evidence that, from the nurses' perspective, the DEU faculty-nurse partnership provides students with superior clinical education experiences and may improve nurse work satisfaction.

The benefits nature provides to people, called ecosystem services, are increasingly recognized and accounted for in assessments of infrastructure development, agricultural management, conservation prioritization, and sustainable sourcing. These assessments are often limited by data, however, a gap with tremendous potential to be filled through Earth observations (EO), which produce a variety of data across spatial and temporal extents and resolutions. Despite widespread recognition of this potential, in practice few ecosystem service studies use EO. Here, we identify challenges and opportunities to using EO in ecosystem service modeling and assessment. Some challenges are technical, related to data awareness, processing, and access. These challenges require systematic investment in model platforms and data management. Other challenges are more conceptual but still systemic; they are byproducts of the structure of existing ecosystem service models and addressing them requires scientific investment in solutions and tools applicable to a wide range of models and approaches. We also highlight new ways in which EO can be leveraged for ecosystem service assessments, identifying promising new areas of research. More widespread use of EO for ecosystem service assessment will only be achieved if all of these types of challenges are addressed. This will require non-traditional funding and partnering opportunities from private and public agencies to promote data exploration, sharing, and archiving. Investing in this integration will be reflected in better and more accurate ecosystem service assessments worldwide.

In southern Amazonia, more than half of all cropland is devoted to the production of two rainfed crops per year, an agricultural practice known as “double cropping” ( DC ). Climate change, including feedbacks between changes in land use and the local climate, is shortening the extent of the historical rainy season in southern Amazonia, increasing the risk of future detrimental environmental conditions, and posing a threat to the intensive DC agriculture that is currently practiced in that region, with potential negative consequences at regional, national, and even global scales. We argue that the conservation of undeveloped forests and savannas in southern Amazonia is supported by socioeconomic justifications and is in the best interests of agribusiness, local governments, and the public.

Carbon losses from forest degradation and disturbances are significant and growing sources of emissions in the Brazilian Amazon. Between 2003 and 2019, degradation and disturbance accounted for 44% of forest carbon losses in the region, compared with 56% from deforestation (forest clearing). We found that land tenure played a decisive role in explaining these carbon losses, with Undesignated Public Forests and Other Lands (e.g., private properties) accounting for the majority (82%) of losses during the study period. Illegal deforestation and land grabbing in Undesignated Public Forests widespread and increasingly are important drivers of forest carbon emissions from the region. In contrast, indigenous Territories and Protected Natural Areas had the lowest emissions, demonstrating their effectiveness in preventing deforestation and maintaining carbon stocks. These trends underscore the urgent need to develop reliable systems for monitoring and reporting on carbon losses from forest degradation and disturbance. Together with improved governance, such actions will be crucial for Brazil to reduce pressure on standing forests; strengthen Indigenous land rights; and design effective climate mitigation strategies needed to achieve its national and international climate commitments.

The climatic effects of large‐scale deforestation in the Indonesian Archipelago are investigated using a fully coupled atmosphere‐ocean model— the Fast Ocean Atmosphere Model (FOAM). Extremely rapid rates of deforestation across the Archipelago motivate this study. We compare two simulations (one with fixed ocean temperatures, another where the ocean responds to changing atmospheric conditions), to investigate the potential for oceanic feedbacks on deforestation‐induced climate change. With fixed sea surface temperatures, evaporation decreases over land but increases over the surrounding oceans where the wind speeds increase. Regional deep convection is enhanced and precipitation increases over the islands. With an interactive ocean the initial decrease in evaporation over the deforested land reduces convergence and increases the easterlies in the Bay of Bengal. More intense equatorial upwelling cools the surface temperatures over that region and reduces ocean evaporation. Regional convection is less intense and precipitation drops by 9% over deforested land.

Exposure to familial alcoholism has been associated with many behavioral and emotional difficulties among offspring. However, few studies have examined environmental risks that often coexist with familial alcoholism, and which may influence the development of offspring psychosocial problems. This study examined potential additive and interactive effects of childhood exposure to family violence and childhood exposure to familial alcoholism on adolescent functioning. Three domains of adolescent functioning were examined in a high-risk community sample of 109 families: lifetime levels of substance use, conduct disorder behaviors, and self-esteem. Results indicated that both childhood exposure to familial alcoholism and childhood exposure to family violence were associated with psychosocial functioning of offspring during adolescence, although the relations differ according to domain of functioning and gender.

The land surface water balance of the continental United States is analyzed from 1963 to 1995 using a terrestrial biosphere model (IBIS), reanalysis data from NCEP/NCAR, a hydrologic routing model (HYDRA), and numerous observational data sets. Emphasis is placed on evaluating the performance of IBIS and the reanalysis, particularly over the central United States. IBIS is forced with daily climatic inputs from NCEP; an additional simulation is performed using observed precipitation. The NCEP reanalysis is found to have excessive precipitation and evapotranspiration over the central United States (particularly in the summertime), an exaggerated seasonal cycle of runoff, and low snow depths. The net surface water balance exhibits a dry bias that is corrected by nudging soil moisture toward climatology. Unfortunately, this correction term is large and appears to have a detrimental impact on other water balance components (particularly runoff). Fields that are reasonably well simulated in the reanalysis include fall and winter precipitation over the central United States, soil moisture in Illinois, and interannual variations in runoff. Results from the IBIS simulations show generally better agreement with observations than the NCEP reanalysis but continue to have nontrivial errors in certain fields. Over the central United States, these discrepancies include high winter/spring evapotranspiration (1 mm d −1 too high), low snow depth, and weak spring runoff (30–50% too low). The errors are at least partially caused by underestimated cloud cover and early spring green‐up. A spatial analysis of the U.S. water balance reveals that some of the strongest seasonal and interannual variations in precipitation, evapotranspiration, and soil moisture occur over the central United States.

Abstract A water stress–compensating root-water-uptake module was developed based upon a newly proposed water stress reduction function and an asymptotic root distribution function. The water stress reduction function takes into account both soil water pressure head and soil resistance to water flow. It requires only physically based parameters that eliminate the need for empirical calibration. The root-water-uptake module, incorporated into a complete Soil–Vegetation–Atmosphere Transfer (SVAT) simulation model, was tested for a variety of soil, crop, and climatic conditions across Canada. Both the proposed water stress reduction and the asymptotic root distribution function performed similarly to existing ones, with the maximum difference in normalized root-mean-square error (NRMSE) between the new and existing water stress reduction function being 0.6%, and between the asymptotic and an exponential root distribution function being 1.2%. The entire root-water-uptake module worked as well as, or better than, published ones. Because the new module uses fewer empirical parameters, it becomes particularly useful in large-scale modeling applications of land surface, hydrology, and terrestrial ecosystems where such parameters are usually not readily available.

Full Access Effects of Climatic Variability and Deforestation on Surface Water Regimes Marcos Heil Costa, Marcos Heil Costa Departamento de Engenharia Agrícola, Universidade Federal de ViçOsaviçosa, BrazilSearch for more papers by this authorMichael T. Coe, Michael T. Coe Woods Hole Research Center Falmouth, Massachusetts, USASearch for more papers by this authorJean Loup Guyot, Jean Loup Guyot LMTG, Institut de Recherche Pour le DéVeloppement Toulouse, FranceSearch for more papers by this author Marcos Heil Costa, Marcos Heil Costa Departamento de Engenharia Agrícola, Universidade Federal de ViçOsaviçosa, BrazilSearch for more papers by this authorMichael T. Coe, Michael T. Coe Woods Hole Research Center Falmouth, Massachusetts, USASearch for more papers by this authorJean Loup Guyot, Jean Loup Guyot LMTG, Institut de Recherche Pour le DéVeloppement Toulouse, FranceSearch for more papers by this author Book Editor(s):Michael Keller, Michael KellerSearch for more papers by this authorMichael Bustamante, Michael BustamanteSearch for more papers by this authorJohn Gash, John GashSearch for more papers by this authorPedro Silva Dias, Pedro Silva DiasSearch for more papers by this author First published: 01 January 2009 https://doi.org/10.1029/2008GM000721Citations: 43Book Series:Geophysical Monograph Series AboutPDFPDFView & download chapterView & download chapterView & download full book ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShareShare a linkShare onEmailFacebookTwitterLinkedInRedditWechat Summary This chapter contains sections titled: Introduction Effects of Climate Variability on River Flow in the Amazon Basin Effects of Climate Variability on Amazon Basin Floodplain Extension Effects of Changes in Land Cover on Amazon Basin Flow Conclusions References R. 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This chapter contains sections titled: Introduction The pan-Arctic watershed Observational data—historical to contemporary time series Projections of future fluxes Conclusions Acknowledgments References

An important measure of an innovation is the ease of replication and achievement of the same positive outcomes. The dedicated education unit (DEU) clinical education model uses a collaborative academic–service partnership to develop an optimal learning environment for students. The University of Portland adapted this model from Flinders University, Australia, to increase the teaching capacity and quality of nursing education. This article identifies DEU implementation essentials and reports on the outcomes of two replication sites that received consultation support from the University of Portland. Program operation information, including education requirements for clinician instructors, types of patient care units, and clinical faculty-to-student ratios is presented. Case studies of the three programs suggest the DEU model is adaptable to a range of different clinical settings and continues to show promise as one strategy for addressing the nurse faculty shortage and strengthening academic–clinical collaborations while maintaining quality clinical education for students. [ J Nurs Educ. 2013;52(5):259–267.]

AIM The study compared students’ perceptions of their clinical learning experiences in a dedicated education unit (DEU) with their experiences in traditional clinical education. BACKGROUND Unlike traditional academic-instructor models, expert nurses in the DEU provide clinical education to students with faculty support. METHOD This repeated measures design used student surveys, supplemented by focus group data. RESULTS Students were more likely to agree that their clinical learning experience was high quality and they had a consistent mentoring relationship during DEU rotations. Students also reported the quality of the unit’s learning environment, the leadership style of the nurse manager, and the nursing care on the unit was more favorable in DEUs than traditional units. Consistent with their changed role in DEUs, faculty members were less active in helping students integrate theory and practice. CONCLUSION These findings provide additional evidence of the value that the DEU model contributes to high-quality clinical education.

Global changes and associated droughts, heat waves, logging activities, and forest fragmentation may intensify fires in Amazonia by altering forest microclimate and fuel dynamics. To isolate the effects of fuel loads on fire behavior and fire-induced changes in forest carbon cycling, we manipulated fine fuel loads in a fire experiment located in southeast Amazonia. We predicted that a 50% increase in fine fuel loads would disproportionally increase fire intensity and severity (i.e., tree mortality and losses in carbon stocks) due to multiplicative effects of fine fuel loads on the rate of fire spread, fuel consumption, and burned area. The experiment followed a fully replicated randomized block design (N = 6) comprised of unburned control plots and burned plots that were treated with and without fine fuel additions. The fuel addition treatment significantly increased burned area (+22%) and consequently canopy openness (+10%), fine fuel combustion (+5%), and mortality of individuals ≥5 cm in diameter at breast height (dbh; +37%). Surprisingly, we observed nonsignificant effects of the fuel addition treatment on fireline intensity, and no significant differences among the three treatments for (i) mortality of large trees (≥30 cm dbh), (ii) aboveground forest carbon stocks, and (iii) soil respiration. It was also surprising that postfire tree growth and wood increment were higher in the burned plots treated with fuels than in the unburned control. These results suggest that (i) fine fuel load accumulation increases the likelihood of larger understory fires and (ii) single, low-intensity fires weakly influence carbon cycling of this primary neotropical forest, although delayed postfire mortality of large trees may lower carbon stocks over the long term. Overall, our findings indicate that increased fine fuel loads alone are unlikely to create threshold conditions for high-intensity, catastrophic fires during nondrought years.

Abstract The Amazon tropical evergreen forest is an important component of the global carbon budget. Its forest floristic composition, structure, and function are sensitive to changes in climate, atmospheric composition, and land use. In this study biomass and productivity simulated by three dynamic global vegetation models (Integrated Biosphere Simulator, Ecosystem Demography Biosphere Model, and Joint UK Land Environment Simulator) for the period 1970–2008 are compared with observations from forest plots (Rede Amazónica de Inventarios Forestales). The spatial variability in biomass and productivity simulated by the DGVMs is low in comparison to the field observations in part because of poor representation of the heterogeneity of vegetation traits within the models. We find that over the last four decades the CO 2 fertilization effect dominates a long‐term increase in simulated biomass in undisturbed Amazonian forests, while land use change in the south and southeastern Amazonia dominates a reduction in Amazon aboveground biomass, of similar magnitude to the CO 2 biomass gain. Climate extremes exert a strong effect on the observed biomass on short time scales, but the models are incapable of reproducing the observed impacts of extreme drought on forest biomass. We find that future improvements in the accuracy of DGVM predictions will require improved representation of four key elements: (1) spatially variable plant traits, (2) soil and nutrients mediated processes, (3) extreme event mortality, and (4) sensitivity to climatic variability. Finally, continued long‐term observations and ecosystem‐scale experiments (e.g. Free‐Air CO 2 Enrichment experiments) are essential for a better understanding of the changing dynamics of tropical forests.

The study region is the Amazon River Basin, which controls globally important water and energy fluxes. In the face of a changing climate and landscape, it is critical that we understand how, where, and why surface water resources are changing. Specifically, we must consider holistic changes to the water cycle to understand how water resources are affected by climate change and landscape alterations. In this study, we investigate changes to all major components of the water balance across the entire Amazon Basin. We seek to understand: 1) how changes to land cover and precipitation affect streamflow, 2) how these factors affect evapotranspiration and groundwater storage water balance components, and 3) how changes to the water balance partitioning may in turn alter streamflows. We find significant changes to streamflow of ±9.5 mm/yr on average across the Amazon Basin. Streamflow alterations show a spatially variable pattern, with increasing discharge in the northern and western portions of the basin, and decreasing discharge in the southern and eastern basin. We also observe significant changes in evapotranspiration of ±29 mm/yr and groundwater storage increases of 7.1 mm/yr. Together, these results indicate that studies of streamflow change in the Amazon should consider changes to the whole water budget, including understudied aspects of groundwater storage across the Basin.

Abstract Several studies in recent decades have warned that plant breeding capacity in U.S. institutions may be declining, placing our food system at risk. To further understand the status, trajectory, and needs of these programs, a national survey was conducted in 2018. Public‐sector plant breeding programs ( n = 278) in 44 U.S. states responded to questions about staffing levels, budgets, access to needed personnel, and access to technology for selective breeding. Almost half of program leaders were nearing retirement age. Programs reported significantly declining estimates of hours spent on program activities by program leaders and technical support staff. On average, programs reported devoting 2.78 full‐time equivalent (FTE) to plant breeding research in the most recent fiscal year (including all types of personnel); for germplasm enhancement activities and variety development, mean estimated hours per program totaled 1.58 and 2.20 FTE, respectively. The median annual operating budget in the most recent fiscal year was US$150,000; the mean (average) annual operating budget was US$266,562. Budget and FTE means are somewhat skewed toward higher figures because of a few unusually large programs; almost 80% of programs reported annual budgets of US$400,000 or less. Institutional funds, federal competitive grants, and commodity check‐off programs accounted for 67% of program budgets. Many programs reported that budget shortfalls or uncertainty “endangered or severely constrained” or seriously constrained their ability to support key personnel, infrastructure and operations, and access to current technology for collecting, analyzing, and applying knowledge from phenotype and genotype data on plant materials in their programs.

Lakes are low‐lying connectors of uplands and wetlands, surface water and groundwater, and though they are often studied as independent ecosystems, they function within complex landscapes. One such highly connected region is the Northern Highland Lake District (NHLD), where more than 7000 lakes and their watersheds cycle water and carbon through mixed forests, wetlands, and groundwater systems. Using a new spatially explicit simulation framework representing these coupled cycles, the Lake, Uplands, Wetlands Integrator (LUWI) model, we address basic regional questions in a 72‐lake simulation: (1) How do simulated water and carbon budgets compare with observations, and what are the implications for carbon stocks and fluxes? (2) How do the strength and spatial pattern of landscape connections vary among watersheds? (3) What is the role of interwatershed connections in lake carbon processing? Results closely coincide with observations at seasonal and annual scales and indicate that the connections among components and watersheds are critical to understanding the region. Carbon and water budgets vary widely, even among nearby lakes, and are not easily predictable using heuristics of lake or watershed size. Connections within and among watersheds exert a complex, varied influence on these processes: Whereas inorganic carbon budgets are strongly related to the number and nature of upstream connections, most organic lake carbon originates within the watershed surrounding each lake. This explicit incorporation of terrestrial and aquatic processes in surface and subsurface connection networks will aid our understanding of the relative roles of on‐land, in‐lake, and between‐lake processes in this lake‐rich region.

Remote sensing is undergoing a fundamental paradigm shift, in which approaches interpreting one or two images are giving way to a wide array of data-rich applications. These include assessing global forest loss, tracking water resources across Earth’s surface, determining disturbance frequency across decades, and many more. These advances have been greatly facilitated by Google Earth Engine, which provides both image access and a platform for advanced analysis techniques. Within the realm of land-use/land-cover (LULC) classifications, Earth Engine provides the ability to create new classifications and to access major existing data sets that have already been created, particularly at global extents. By overlaying global LULC classifications—the 300-m GlobCover 2009 LULC data set for example—with sharper images like those from Landsat, one can see the promise and limits of these global data sets and platforms to fuse them. Despite the promise in a global classification covering all of the terrestrial surface, GlobCover 2009 may be too coarse for some applications. We asked whether the LULC labeling provided by GlobCover 2009 could be combined with the spatial granularity of the Landsat platform to produce a hybrid classification having the best features of both resources with high accuracy. Here we apply an improvement of the Bayesian Updating of Land Cover (BULC) algorithm that fused unsupervised Landsat classifications to GlobCover 2009, sharpening the result from a 300-m to a 30-m classification. Working with four clear categories in Mato Grosso, Brazil, we refined the resolution of the LULC classification by an order of magnitude while improving the overall accuracy from 69.1 to 97.5%. This “BULC-U” mode, because it uses unsupervised classifications as inputs, demands less region-specific knowledge from analysts and may be significantly easier for non-specialists to use. This technique can provide new information to land managers and others interested in highly accurate classifications at finer scales.

We performed a Water Footprint Sustainability Assessment (WFSA) in the Xingu Basin of Mato Grosso (XBMT), Brazil, with the objectives of (1) tracking blue (as surface water) and green water (as soil moisture regenerated by precipitation) consumption in recent years (2000, 2014); and (2) evaluating agricultural intensification options for future years (2030, 2050) considering the effects of deforestation and climate change on water availability in the basin. The agricultural sector was the largest consumer of water in the basin despite there being almost no irrigation of cropland or pastures. In addition to water use by crops and pasture grass, water consumption attributed to cattle production included evaporation from roughly 9463 ha of small farm reservoirs used to provide drinking water for cattle in 2014. The WFSA showed that while blue and green water consumptive uses were within sustainable limits in 2014, deforestation, cattle confinement, and the use of irrigation to increase cropping frequency could drive water use to unsustainable levels in the future. While land management policies and practices should strive for protection of the remaining natural vegetation, increased agricultural production will require reservoir and irrigation water management to reduce the potential threat of blue water scarcity in the dry season. In addition to providing general guidance for future water allocation decisions in the basin, our study offers an interpretation of blue and green water scarcities with changes in land use and climate in a rapidly evolving agricultural frontier.

Abstract The availability of freshwater is a particularly important issue in Africa where large portions of the continent are arid or semiarid and climate is highly variable. Sustainable water resource management requires the assessment of hydrological variability in response to nature climate fluctuation. In this study, a land surface model, the Integrated Biosphere Simulator (IBIS), and a hydrological routing model, the Hydrological Routing Algorithm (HYDRA), are used to investigate the hydrological variability in two large basins, the Lake Chad basin (LCB) and the Niger River basin (NRB), located in West Africa, over the period from 1950 to 1995. The IBIS land surface hydrological module was calibrated and validated for arid and semiarid Africa, and major enhancements were made to the module, including the development of a dynamic root water–extraction formulation, the incorporation of a Green–Ampt infiltration parameterization, and modification to the prescribed root distribution, the runoff module, and weather generator. The results show that the hydrology in this area is highly variable over time and space. The coefficient of variance (CV) of annual rainfall ranges from 10%–15% in the southern portions of the basins to 30%–40% in the northern portions. The annual evapotranspiration (ET) varies with a slightly lower CV compared to the rainfall, but the runoff is extremely sensitive to the rainfall fluctuation, particularly in the central portions of the basins (8°–13°N in LCB and 12°–16°N in NRB) where the CVs in runoff are as high as 100%–200%. The annual river discharge varies largely in concert with the rainfall fluctuation, with the CV being 37% in LCB and 23%–63% in NRB. In terms of the whole basin, the relative hydrologic variability (rainfall, evapotranspiration, runoff, and river discharge) is significantly higher in the dry period than in the wet period, and the interannual variability in runoff is more than twice as high as compared to rainfall or ET.

Abstract Seasonally dry tropical forests (SDTFs) account for one-third of the interannual variability of global net primary productive (NPP). Large-scale shifts in dry tropical forest structure may thus significantly affect global CO 2 fluxes in ways that are not fully accounted for in current projections. This study quantifies how changing climate might reshape one of the largest SDTFs in the world, the Caatinga region of northeast Brazil. We combine historical data and future climate projections under different representative concentration pathways (RCPs), together with spatially explicit aboveground biomass estimates to establish relationships between climate and vegetation distribution. We find that physiognomies, aboveground biomass, and climate are closely related in the Caatinga—and that the region’s bioclimatic envelope is shifting rapidly. From 2008–2017, more than 90% of the region has shifted to a dryer climate space compared to the reference period 1950–1979. An ensemble of global climate models (based on IPCC AR5) indicates that by the end of the 21st century the driest Caatinga physiognomies (thorn woodlands to non-vegetated areas) could expand from 55% to 78% (RCP 2.6) or as much as 87% (RCP8.5) of the region. Those changes would correspond to a decrease of 30%–50% of the equilibrium aboveground biomass by the end of the century (RCP 2.6 and RCP8.5, respectively). Our results are consistent with historic vegetation shifts reported for other SDTFs. Projected changes for the Caatinga would have large-scale impacts on the region’s biomass and biodiversity, underscoring the importance of SDTFs for the global carbon budget. Understanding such changes as presented in this study will be useful for regional planning and could help mitigate their negative social impacts.

Droughts can exert a strong influence on the regional energy balance of the Amazon and Cerrado, as can the replacement of native vegetation by croplands. What remains unclear is how these two forcing factors interact and whether land cover changes fundamentally alter the sensitivity of the energy balance components to drought events. To fill this gap, we used remote sensing data to evaluate the impacts of drought on evapotranspiration (ET), land surface temperature (LST), and albedo on cultivated areas, savannas, and forests. Our results (for seasonal drought) indicate that increases in monthly dryness across Mato Grosso state (southern Amazonia and northern Cerrado) drive greater increases in LST and albedo in croplands than in forests. Furthermore, during the 2007 and 2010 droughts, croplands became hotter (0.1–0.8 °C) than savannas (0.3–0.6 °C) and forests (0.2–0.3 °C). However, forest ET was consistently higher than ET in all other land uses. This finding likely indicates that forests can access deeper soil water during droughts. Overall, our findings suggest that forest remnants can play a fundamental role in the mitigation of the negative impacts of extreme drought events, contributing to a higher ET and lower LST.

The Pervasive Sensing group at the University of Birmingham is exploring in-orbit conditional monitoring of satellites using inverse synthetic aperture radar (ISAR) as a technique for dedicated observation of high-value space-based assets. In this work, the feasibility of geostationary orbit (GEO) observation by optimising monitoring satellite orbital parameters for sub-THz ISAR data acquisition has been assessed. A proprietary propagation simulator, Gofod, has been used to devise the scenarios for which launch conditions, stability, periodicity and time of dwell on the target will deliver the best observation of key observed satellite features. Simulation results have been validated with commercial software.

Large-scale commercial cropping of soybeans expanded in the tropical Amazon and Cerrado biomes of Brazil after 1990. More recently, cropping intensified from single-cropping of soybeans to double-cropping of soybeans with corn or cotton. Cropland expansion and intensification, and the accompanying use of mineral fertilizers, raise concerns about whether nutrient runoff and impacts to surface waters will be similar to those experienced in commercial cropland regions at temperate latitudes. We quantified water infiltration through soils, water yield, and streamwater chemistry in watersheds draining native tropical forest and single- and double-cropped areas on the level, deep, highly weathered soils where cropland expansion and intensification typically occurs. Although water yield increased four-fold from croplands, streamwater chemistry remained largely unchanged. Soil characteristics exerted important control over the movement of nitrogen (N) and phosphorus (P) into streams. High soil infiltration rates prevented surface erosion and movement of particulate P, while P fixation in surface soils restricted P movement to deeper soil layers. Nitrogen retention in deep soils, likely by anion exchange, also appeared to limit N leaching and export in streamwater from both single- and double-cropped watersheds that received nitrogen fertilizer. These mechanisms led to lower streamwater P and N concentrations and lower watershed N and P export than would be expected, based on studies from temperate croplands with similar cropping and fertilizer application practices.

With the rise of commercial constellation implementation in low earth orbit (LEO), the near-Earth space environment is becoming increasingly challenging to monitor and protect. As well as carefully considered policy frameworks, new observational techniques and instrumentation are needed to ensure that safe operations can be maintained by all space users. The Pervasive Sensing group at the University of Birmingham is exploring in-orbit conditional monitoring of satellites using inverse synthetic aperture radar (ISAR) as a technique for dedicated observation of high-value space-based assets. Our previous concept and design results for fixed-beam dual freqency ISAR observations in circular orbits have been extended to a variety of scenarios. I will discuss some of our recent results from both experiments and simulation.&amp;#160;

A model (SWAM) to predict surface waters (lakes and wetlands) on the scale of atmospheric general circulation models is developed. SWAM is based on a linear reservoir hydrologic model and is driven by runoff, precipitation, evaporation, topography, and water transport directions. SWAM is applied to the modern climate using observed estimates of the hydrologic variables and a 5′ × 5′ digital terrain model to represent topography. It simulates the surface water area of northern Africa (about 1% of the land area) in reasonable agreement with observed estimates (0.65%). A middle Holocene (6000 yr BP) simulation using the results of the GENESIS atmospheric general circulation model (AGCM) illustrates the sensitivity of the simulated surface waters to climatic changes and the model’s utility as a diagnostic tool for AGCMs. SWAM and GENESIS capture the general pattern of climate change 6000 yr BP. There is an increase in the simulated surface water area from about 1% to about 3% of the land area, including an increase in the area of Lake Chad by about five times and extensive surface water throughout northern Mali, consistent with observed patterns of surface water change during the Holocene. Limitations in the modeling of surface waters appear to result from the relatively coarse resolution of global elevation data.

The Mississippi Basin is the third largest drainage basin in the world and is home to one of the most productive agricultural regions on Earth. Here we discuss how land use/land cover change and climatic variability may be affecting some key environmental processes across the Mississippi and how these, in turn, affect the flow of selected ecosystem goods and services in the region. Specifically, we consider the recent history of land use/land cover change, crop yields, basin river flow and hydrology, and large-scale water quality in the Mississippi Basin. We find that agricultural activities may have had a profound influence on the basin and may have shifted the flow of many ecosystem goods and services into agricultural commodities, at the expense of altering many of the important biogeochemical linkages between atmosphere, land, and water.

Abstract The Caspian Sea (CS) is the largest inland lake in the world. Large variations in sea level and surface area occurred in the past and are projected for the future. The potential impacts on regional and large‐scale hydroclimate are not well understood. Here, we examine the impact of CS area on climate within its catchment and across the northern hemisphere, for the first time with a fully coupled climate model. The Community Earth System Model (CESM1.2.2) is used to simulate the climate of four scenarios: (a) larger than present CS area, (b) current area, (c) smaller than present area, and (d) no‐CS scenario. The results reveal large changes in the regional atmospheric water budget. Evaporation (e) over the sea increases with increasing area, while precipitation (P) increases over the south‐west CS with increasing area. P‐E over the CS catchment decreases as CS surface area increases, indicating a dominant negative lake‐evaporation feedback. A larger CS reduces summer surface air temperatures and increases winter temperatures. The impacts extend eastwards, where summer precipitation is enhanced over central Asia and the north‐western Pacific experiences warming with reduced winter sea ice. Our results also indicate weakening of the 500‐hPa troughs over the northern Pacific with larger CS area. We find a thermal response triggers a southward shift of the upper troposphere jet stream during summer. Our findings establish that changing CS area results in climate impacts of such scope that CS area variations should be incorporated into climate model simulations, including palaeo and future scenarios.

We evaluated the performance of the Integrated BIosphere Simulator (IBIS) land surface model in the temperate forests of northern Wisconsin (46°N, 89°W) to determine whether model formulations, driven with daily historical precipitation, temperature, relative humidity, solar radiation, and wind speed data, were capable of simulating water flow and storage within a seasonally cold climate regime. We focused concurrently on understanding seasonal and interannual variations of both the water fluxes to the atmosphere and water partitioned into surface runoff and groundwater infiltration, with special attention to the transitions from cold‐dominated (snow, ice) to warm‐dominated (rain, liquid soil moisture) hydrology. Results showed when compared with a suite of field observations IBIS simulated water and energy cycling at daily to interannual timescales with reasonable accuracy. Because of errors associated with field observations, the accuracy with which we simulated each component of the water balance is not easily quantified. By investigating the complete land surface water balance, however, we increased the likelihood that all components were being captured. The modeled monthly energy balance, annual water balance, and drainage rates were generally within 5–15% of the observed values. Modeled and observed soil temperatures generally differed by less than 3°C and had r 2 values that were greater than 0.9. Soil moisture values were within 5–20%, and freeze and thaw timing was within a few days of observations. Modeled snow dynamics captured the observed snow arrival and departure (accumulation on the surface) within a few days of observations, but overestimated the average maximum depth by 86%. Because model formulations were subjected to varying soil conditions and water phases, this evaluation exercise enhanced our understanding of northern Wisconsin's water balance and increased model credibility for applications in seasonally cold climates.

ABSTRACT ABSTRACT National studies indicate that alcohol and drug involvement increases during transition from adolescence to young adulthood. The present study evaluated change in alcohol and drug use as youth move from living with their family of origin to independent living environments. Two samples of youth, those who had previously been treated for alcohol and drug problems (n = 102), and a sample of non-abusing youth (n = 70) with comparable socioeconomic backgrounds and family history of alcohol dependence, were compared as they transitioned into their first independent living environment. There was a 35% increase in the number of monthly drinking episodes across this transition to independent living, and a 46% increase in number of drinks per week. Drug involvement was less affected by this developmental transition, however a larger proportion of teens with a history of substance problems reported use of drugs (31% vs. 48%) following transition to independent living. Both level of exposure to substances in the new environment and peer substance use were significant predictors of post-transition substance involvement. Findings highlight significant changes in alcohol involvement in relation to this critical developmental transition of late adolescence and young adulthood. KEYWORDS: Transitionindependent livingsubstance abusehigh risk youth

Abstract Water distributed in deep soil reservoirs is an important factor determining the ecosystem structure of water-limited environments, such as the seasonal tropical savannas of South America. In this study a two-dimensional (2D) geoelectrical profiling technique was employed to estimate seasonal dynamics of soil water content to 10-m depth along transects of 275 m in savanna vegetation during the period between 2002 and 2006. Methods were developed to convert resistivity values along these 2D resistivity profiles into volumetric water content (VWC) by soil depth. The 2D resistivity profiles revealed the following soil and aquifer structure characterizing the underground environment: 0–4 m of permanently unsaturated and seasonally droughty soil, less severely dry unsaturated soil at about 4–7 m, nearly permanently saturated soil between 7 and 10 m, mostly impermeable saprolite interspaced with fresh bedrock of parent material at about 10–30 m, and a region of highly conductive water-saturated material at 30 m and below. Considerable spatial variation of these relative depths is clearly demonstrated along the transects. Temporal dynamics in VWC indicate that the active zone of water uptake is predominantly at 0–7 m, and follows the seasonal cycles of precipitation and evapotranspiration. Uptake from below 7 m may have been critical for a short period near the beginning of the rainy season, although the seasonal variations in VWC in the 7–10-m layer are relatively small and lag the surface water recharge for about 6 months. Calculations using a simple 1-box water balance model indicate that average total runoff was 15–25 mm month−1 in the wet season and about 6–9 mm month−1 in the dry season. Modeled ET was about 75–85 mm month−1 in the wet season and 20–25 mm month−1 in the dry season. Variation in basal area and tree density along one transect was positively correlated with VWC of the 0–3-m and 0–7-m soil depths, respectively, during the wettest months. These multitemporal measurements demonstrate that the along-transect spatial differences in soil moisture are quasi-permanent and influence vegetation structure at the scale of tens to hundreds of meters.

The Brazilian savanna biome, known locally as the Cerrado, with an area of about 2 million km2 and marked by a conspicuous seasonality, comprises a vertically structured mosaic of ecosystem types, ranging from grassland to tropical dry forests. The Cerrado is a major agricultural frontier in Brazil, with nearly 50% of its original vegetative cover already converted to pastures and crop fields. Such large-scale conversion has severely affected regional runoff, river discharge and the atmosphere water transfer from soil reservoirs through vegetation. In this study, we used multitemporal Earth Observing-1 (EO-1) Hyperion hyperspectral imagery to derive canopy water content (validated by ground truth measurements), whose estimates were regionally extrapolated, over the entire Cerrado biome, based on the normalized difference vegetation index (NDVI) Moderate Resolution Imaging Spectroradiometer (MODIS) product MOD13Q1. MODIS-based canopy-level equivalent water thickness (EWTC) values were significantly distinct for each of the major anthropogenic and natural Cerrado land-cover types, at both the beginning and end of the dry season, and were correlated with land surface temperatures (LSTs). This method provides reasonable estimates of precipitable canopy water. Potential applications of EWTC estimates based on moderate resolution imagery include early fire warnings and validation and constraining of regional hydrological models.

The Amazon basin is the planet's largest and most intense land-based centre of precipitation. This convective system is driven by high net surface radiation, which is dissipated via fluxes of latent heat and sensible heat. Over the long term (1 year or greater), incoming precipitation over the basin is balanced by evaporative fluxes of water to the atmosphere and discharge, which returns excess water to the oceans. The temporal variability of this cycle is largely controlled by oscillations of tropical Pacific and North Atlantic sea surface temperatures, while synergies between climate and forest structure and functioning control much of the observed spatial variability. Field observations and numerical models indicate that large-scale deforestation has decreased net surface radiation and evapotranspiration, increasing sensible heat flux, water yield, and stream discharge in many locations, particularly in the agricultural frontier of southeastern Amazonia. In the future, increasing atmospheric greenhouse gases are expected to increase temperatures, drought frequency, and drought intensity in the Amazon, causing further changes to the cycling of energy and water in the basin.