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Eiras-Barca J, Dominguez F, Yang Z, Chug D, Nieto R, Gimeno L, Miguez-Macho G. Changes in South American hydroclimate under projected Amazonian deforestation. Ann N Y Acad Sci 2020; 1472:104-122. [PMID: 32441831 DOI: 10.1111/nyas.14364] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 03/28/2020] [Accepted: 04/20/2020] [Indexed: 11/26/2022]
Abstract
Continued deforestation in the Amazon forest can alter the subsurface/surface and atmospheric branches of the hydrologic cycle. The sign and magnitude of these changes depend on the complex interactions between the water, energy, and momentum budgets. To understand these changes, we use the weather research and forecasting (WRF) model with improved representation of groundwater dynamics and the added feature of Amazonian moisture tracers. The control simulation uses moderate resolution imaging spectroradiometer (MODIS) based observations of land use, and the deforestation simulations use a "business-as-usual" scenario projected for 2040-2050. Our results show that deforestation leads to changes that are seasonally very different. During the dry season, deforestation results in increased albedo and less available net radiation. This change, together with reduced leaf area, results in decreased evapotranspiration (ET), less atmospheric moisture of Amazonian origin, and an increase in temperature. However, we find no changes in precipitation over the basin. Conversely, during the wet season, surface winds increase significantly due to decreased surface roughness. Vapor transport increases throughout the deforested region and leads to an increase in easterly moisture export, and significant decrease in precipitation within the deforested regions of Eastern Amazon. Contrary to expectations, the moisture tracers in WRF show no evidence that precipitation decreases are due to recycling or changes in stability.
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Affiliation(s)
- Jorge Eiras-Barca
- Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Environmental Physics Laboratory (EPhysLab), CIM-UVIGO, Universidade de Vigo, Ourense, Spain
| | - Francina Dominguez
- Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Zhao Yang
- Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Pacific Northwest National Laboratory, Richland, Washington
| | - Divyansh Chug
- Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Raquel Nieto
- Environmental Physics Laboratory (EPhysLab), CIM-UVIGO, Universidade de Vigo, Ourense, Spain
| | - Luis Gimeno
- Environmental Physics Laboratory (EPhysLab), CIM-UVIGO, Universidade de Vigo, Ourense, Spain
| | - Gonzalo Miguez-Macho
- Non-Linear Physics Group, Universidade de Santiago de Compostela, Galicia, Spain
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Laurance WF, Camargo JLC, Fearnside PM, Lovejoy TE, Williamson GB, Mesquita RCG, Meyer CFJ, Bobrowiec PED, Laurance SGW. An Amazonian rainforest and its fragments as a laboratory of global change. Biol Rev Camb Philos Soc 2017; 93:223-247. [PMID: 28560765 DOI: 10.1111/brv.12343] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 04/27/2017] [Accepted: 05/03/2017] [Indexed: 11/29/2022]
Abstract
We synthesize findings from one of the world's largest and longest-running experimental investigations, the Biological Dynamics of Forest Fragments Project (BDFFP). Spanning an area of ∼1000 km2 in central Amazonia, the BDFFP was initially designed to evaluate the effects of fragment area on rainforest biodiversity and ecological processes. However, over its 38-year history to date the project has far transcended its original mission, and now focuses more broadly on landscape dynamics, forest regeneration, regional- and global-change phenomena, and their potential interactions and implications for Amazonian forest conservation. The project has yielded a wealth of insights into the ecological and environmental changes in fragmented forests. For instance, many rainforest species are naturally rare and hence are either missing entirely from many fragments or so sparsely represented as to have little chance of long-term survival. Additionally, edge effects are a prominent driver of fragment dynamics, strongly affecting forest microclimate, tree mortality, carbon storage and a diversity of fauna. Even within our controlled study area, the landscape has been highly dynamic: for example, the matrix of vegetation surrounding fragments has changed markedly over time, succeeding from large cattle pastures or forest clearcuts to secondary regrowth forest. This, in turn, has influenced the dynamics of plant and animal communities and their trajectories of change over time. In general, fauna and flora have responded differently to fragmentation: the most locally extinction-prone animal species are those that have both large area requirements and low tolerance of the modified habitats surrounding fragments, whereas the most vulnerable plants are those that respond poorly to edge effects or chronic forest disturbances, and that rely on vulnerable animals for seed dispersal or pollination. Relative to intact forests, most fragments are hyperdynamic, with unstable or fluctuating populations of species in response to a variety of external vicissitudes. Rare weather events such as droughts, windstorms and floods have had strong impacts on fragments and left lasting legacies of change. Both forest fragments and the intact forests in our study area appear to be influenced by larger-scale environmental drivers operating at regional or global scales. These drivers are apparently increasing forest productivity and have led to concerted, widespread increases in forest dynamics and plant growth, shifts in tree-community composition, and increases in liana (woody vine) abundance. Such large-scale drivers are likely to interact synergistically with habitat fragmentation, exacerbating its effects for some species and ecological phenomena. Hence, the impacts of fragmentation on Amazonian biodiversity and ecosystem processes appear to be a consequence not only of local site features but also of broader changes occurring at landscape, regional and even global scales.
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Affiliation(s)
- William F Laurance
- Centre for Tropical Environmental and Sustainability Science (TESS) and College of Science and Engineering, James Cook University, Cairns, 4878, Australia.,Biological Dynamics of Forest Fragments Project, National Institute for Amazonian Research (INPA) and Smithsonian Tropical Research Institute, Manaus, 69067-375, Brazil
| | - José L C Camargo
- Biological Dynamics of Forest Fragments Project, National Institute for Amazonian Research (INPA) and Smithsonian Tropical Research Institute, Manaus, 69067-375, Brazil
| | - Philip M Fearnside
- Department of Environmental Dynamics, National Institute for Amazonian Research (INPA), Manaus, 69067-375, Brazil
| | - Thomas E Lovejoy
- Biological Dynamics of Forest Fragments Project, National Institute for Amazonian Research (INPA) and Smithsonian Tropical Research Institute, Manaus, 69067-375, Brazil.,Department of Environmental Science and Policy, George Mason University, Fairfax, VA, 22030, U.S.A
| | - G Bruce Williamson
- Biological Dynamics of Forest Fragments Project, National Institute for Amazonian Research (INPA) and Smithsonian Tropical Research Institute, Manaus, 69067-375, Brazil.,Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, U.S.A
| | - Rita C G Mesquita
- Biological Dynamics of Forest Fragments Project, National Institute for Amazonian Research (INPA) and Smithsonian Tropical Research Institute, Manaus, 69067-375, Brazil.,Department of Environmental Dynamics, National Institute for Amazonian Research (INPA), Manaus, 69067-375, Brazil
| | - Christoph F J Meyer
- Biological Dynamics of Forest Fragments Project, National Institute for Amazonian Research (INPA) and Smithsonian Tropical Research Institute, Manaus, 69067-375, Brazil.,Centre for Ecology, Evolution and Environmental Changes, University of Lisbon, 1749-016, Lisbon, Portugal.,School of Environment and Life Sciences, University of Salford, Salford, M5 4WT, U.K
| | - Paulo E D Bobrowiec
- Biodiversity Coordination, National Institute for Amazonian Research (INPA), Manaus, 69067-375, Brazil
| | - Susan G W Laurance
- Centre for Tropical Environmental and Sustainability Science (TESS) and College of Science and Engineering, James Cook University, Cairns, 4878, Australia.,Biological Dynamics of Forest Fragments Project, National Institute for Amazonian Research (INPA) and Smithsonian Tropical Research Institute, Manaus, 69067-375, Brazil
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Bala G, Caldeira K, Wickett M, Phillips TJ, Lobell DB, Delire C, Mirin A. Combined climate and carbon-cycle effects of large-scale deforestation. Proc Natl Acad Sci U S A 2007; 104:6550-5. [PMID: 17420463 PMCID: PMC1871823 DOI: 10.1073/pnas.0608998104] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The prevention of deforestation and promotion of afforestation have often been cited as strategies to slow global warming. Deforestation releases CO(2) to the atmosphere, which exerts a warming influence on Earth's climate. However, biophysical effects of deforestation, which include changes in land surface albedo, evapotranspiration, and cloud cover also affect climate. Here we present results from several large-scale deforestation experiments performed with a three-dimensional coupled global carbon-cycle and climate model. These simulations were performed by using a fully three-dimensional model representing physical and biogeochemical interactions among land, atmosphere, and ocean. We find that global-scale deforestation has a net cooling influence on Earth's climate, because the warming carbon-cycle effects of deforestation are overwhelmed by the net cooling associated with changes in albedo and evapotranspiration. Latitude-specific deforestation experiments indicate that afforestation projects in the tropics would be clearly beneficial in mitigating global-scale warming, but would be counterproductive if implemented at high latitudes and would offer only marginal benefits in temperate regions. Although these results question the efficacy of mid- and high-latitude afforestation projects for climate mitigation, forests remain environmentally valuable resources for many reasons unrelated to climate.
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Affiliation(s)
- G Bala
- Energy and Environment Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
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Laurance WF. Forest-climate interactions in fragmented tropical landscapes. Philos Trans R Soc Lond B Biol Sci 2004; 359:345-52. [PMID: 15212089 PMCID: PMC1693331 DOI: 10.1098/rstb.2003.1430] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In the tropics, habitat fragmentation alters forest-climate interactions in diverse ways. On a local scale (less than 1 km), elevated desiccation and wind disturbance near fragment margins lead to sharply increased tree mortality, thus altering canopy-gap dynamics, plant community composition, biomass dynamics and carbon storage. Fragmented forests are also highly vulnerable to edge-related fires, especially in regions with periodic droughts or strong dry seasons. At landscape to regional scales (10-1000 km), habitat fragmentation may have complex effects on forest-climate interactions, with important consequences for atmospheric circulation, water cycling and precipitation. Positive feedbacks among deforestation, regional climate change and fire could pose a serious threat for some tropical forests, but the details of such interactions are poorly understood.
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Affiliation(s)
- William F Laurance
- Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Republic of Panamá.
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