Vegetation‐modulated landscape evolution: Effects of vegetation on landscape processes, drainage density, and topography
Identifieur interne : 000C25 ( Istex/Corpus ); précédent : 000C24; suivant : 000C26Vegetation‐modulated landscape evolution: Effects of vegetation on landscape processes, drainage density, and topography
Auteurs : Erkan Istanbulluoglu ; Rafael L. BrasSource :
- Journal of Geophysical Research: Earth Surface [ 0148-0227 ] ; 2005-06.
Abstract
Topography acts as a template for numerous landscape processes that include hydrologic, ecologic, and biologic phenomena. These processes not only interact with each other but also contribute to shaping the landscape as they influence geomorphic processes. We have investigated the effects of vegetation on thresholds for channel initiation and landform evolution using both analytical and numerical approaches. Vegetation is assumed to form a uniform ground cover. Runoff erosion is modeled based on a power function of excess shear stress, in which shear stress efficiency is inversely proportional to vegetation cover. This approach is validated using data. Plant effect on slope stability is represented by additional cohesion provided by plant roots. Vegetation cover is assumed to reduce sediment transport rates due to physical creep processes (rainsplash, dry ravel, and expansion and contraction of sediments) according to a negative exponential relationship. Vegetation grows as a function of both available cover and unoccupied space by plants and is killed by geomorphic disturbances (runoff erosion and landsliding) and wildfires. Analytical results suggest that in an equilibrium basin with a fixed vegetation cover, plants may cause a transition in the dominant erosion process at the channel head. A runoff erosion–dominated landscape, under none or poor vegetation cover, may become landslide dominated under a denser vegetation cover. The sign of the predicted relationship between drainage density and vegetation cover depends on the relative influence of vegetation on different erosion phenomena. With model parameter values representative of the Oregon Coast Range (OCR), numerical experiments conducted using the Channel Hillslope Integrated Landscape Development (CHILD) model confirm the findings based on the analytical theory. A highly dissected fluvial landscape emerges when surface is assumed bare. When vegetation cover is modeled, landscape relief increases, resulting in hollow erosion dominated by landsliding. Interestingly, our simulations underscore the importance of vegetation disturbances by geomorphic events and wildfires on the landscape structure. Simulated landscapes resemble real‐world catchments in the OCR when such disturbances are considered.
Url:
DOI: 10.1029/2004JF000249
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These processes not only interact with each other but also contribute to shaping the landscape as they influence geomorphic processes. We have investigated the effects of vegetation on thresholds for channel initiation and landform evolution using both analytical and numerical approaches. Vegetation is assumed to form a uniform ground cover. Runoff erosion is modeled based on a power function of excess shear stress, in which shear stress efficiency is inversely proportional to vegetation cover. This approach is validated using data. Plant effect on slope stability is represented by additional cohesion provided by plant roots. Vegetation cover is assumed to reduce sediment transport rates due to physical creep processes (rainsplash, dry ravel, and expansion and contraction of sediments) according to a negative exponential relationship. Vegetation grows as a function of both available cover and unoccupied space by plants and is killed by geomorphic disturbances (runoff erosion and landsliding) and wildfires. Analytical results suggest that in an equilibrium basin with a fixed vegetation cover, plants may cause a transition in the dominant erosion process at the channel head. A runoff erosion–dominated landscape, under none or poor vegetation cover, may become landslide dominated under a denser vegetation cover. The sign of the predicted relationship between drainage density and vegetation cover depends on the relative influence of vegetation on different erosion phenomena. With model parameter values representative of the Oregon Coast Range (OCR), numerical experiments conducted using the Channel Hillslope Integrated Landscape Development (CHILD) model confirm the findings based on the analytical theory. A highly dissected fluvial landscape emerges when surface is assumed bare. When vegetation cover is modeled, landscape relief increases, resulting in hollow erosion dominated by landsliding. Interestingly, our simulations underscore the importance of vegetation disturbances by geomorphic events and wildfires on the landscape structure. Simulated landscapes resemble real‐world catchments in the OCR when such disturbances are considered.</div></front></TEI><istex><corpusName>wiley</corpusName><author><json:item><name>Erkan Istanbulluoglu</name><affiliations><json:string>Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Massachusetts, Cambridge, USA</json:string><json:string>E-mail: erkan@mit.edu</json:string></affiliations></json:item><json:item><name>Rafael L. 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Vegetation grows as a function of both available cover and unoccupied space by plants and is killed by geomorphic disturbances (runoff erosion and landsliding) and wildfires. Analytical results suggest that in an equilibrium basin with a fixed vegetation cover, plants may cause a transition in the dominant erosion process at the channel head. A runoff erosion–dominated landscape, under none or poor vegetation cover, may become landslide dominated under a denser vegetation cover. The sign of the predicted relationship between drainage density and vegetation cover depends on the relative influence of vegetation on different erosion phenomena. With model parameter values representative of the Oregon Coast Range (OCR), numerical experiments conducted using the Channel Hillslope Integrated Landscape Development (CHILD) model confirm the findings based on the analytical theory. A highly dissected fluvial landscape emerges when surface is assumed bare. When vegetation cover is modeled, landscape relief increases, resulting in hollow erosion dominated by landsliding. Interestingly, our simulations underscore the importance of vegetation disturbances by geomorphic events and wildfires on the landscape structure. 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Analytical results suggest that in an equilibrium basin with a fixed vegetation cover, plants may cause a transition in the dominant erosion process at the channel head. A runoff erosion–dominated landscape, under none or poor vegetation cover, may become landslide dominated under a denser vegetation cover. The sign of the predicted relationship between drainage density and vegetation cover depends on the relative influence of vegetation on different erosion phenomena. With model parameter values representative of the Oregon Coast Range (OCR), numerical experiments conducted using the Channel Hillslope Integrated Landscape Development (CHILD) model confirm the findings based on the analytical theory. A highly dissected fluvial landscape emerges when surface is assumed bare. When vegetation cover is modeled, landscape relief increases, resulting in hollow erosion dominated by landsliding. 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These processes not only interact with each other but also contribute to shaping the landscape as they influence geomorphic processes. We have investigated the effects of vegetation on thresholds for channel initiation and landform evolution using both analytical and numerical approaches. Vegetation is assumed to form a uniform ground cover. Runoff erosion is modeled based on a power function of excess shear stress, in which shear stress efficiency is inversely proportional to vegetation cover. This approach is validated using data. Plant effect on slope stability is represented by additional cohesion provided by plant roots. Vegetation cover is assumed to reduce sediment transport rates due to physical creep processes (rainsplash, dry ravel, and expansion and contraction of sediments) according to a negative exponential relationship. Vegetation grows as a function of both available cover and unoccupied space by plants and is killed by geomorphic disturbances (runoff erosion and landsliding) and wildfires. Analytical results suggest that in an equilibrium basin with a fixed vegetation cover, plants may cause a transition in the dominant erosion process at the channel head. A runoff erosion–dominated landscape, under none or poor vegetation cover, may become landslide dominated under a denser vegetation cover. The sign of the predicted relationship between drainage density and vegetation cover depends on the relative influence of vegetation on different erosion phenomena. With model parameter values representative of the Oregon Coast Range (OCR), numerical experiments conducted using the Channel Hillslope Integrated Landscape Development (CHILD) model confirm the findings based on the analytical theory. A highly dissected fluvial landscape emerges when surface is assumed bare. When vegetation cover is modeled, landscape relief increases, resulting in hollow erosion dominated by landsliding. Interestingly, our simulations underscore the importance of vegetation disturbances by geomorphic events and wildfires on the landscape structure. Simulated landscapes resemble real‐world catchments in the OCR when such disturbances are considered.</p></abstract></abstractGroup></contentMeta></header></component></istex:document></istex:metadataXml><mods version="3.6"><titleInfo lang="en"><title>Vegetation‐modulated landscape evolution: Effects of vegetation on landscape processes, drainage density, and topography</title></titleInfo><titleInfo type="abbreviated"><title>VEGETATION‐MODULATED LANDSCAPE EVOLUTION</title></titleInfo><titleInfo type="alternative" contentType="CDATA" lang="en"><title>Vegetation‐modulated landscape evolution: Effects of vegetation on landscape processes, drainage density, and topography</title></titleInfo><name type="personal"><namePart type="given">Erkan</namePart><namePart type="family">Istanbulluoglu</namePart><affiliation>Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Massachusetts, Cambridge, USA</affiliation><affiliation>E-mail: erkan@mit.edu</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Rafael L.</namePart><namePart type="family">Bras</namePart><affiliation>Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Massachusetts, Cambridge, USA</affiliation><role><roleTerm type="text">author</roleTerm></role></name><typeOfResource>text</typeOfResource><genre type="article" displayLabel="article"></genre><originInfo><publisher>Blackwell Publishing Ltd</publisher><dateIssued encoding="w3cdtf">2005-06</dateIssued><dateCaptured encoding="w3cdtf">2004-10-08</dateCaptured><dateValid encoding="w3cdtf">2005-02-28</dateValid><edition>Istanbulluoglu, E., and R. L. Bras (2005), Vegetation‐modulated landscape evolution: Effects of vegetation on landscape processes, drainage density, and topography, J. Geophys. Res., 110, F02012, doi:10.1029/2004JF000249.</edition><copyrightDate encoding="w3cdtf">2005</copyrightDate></originInfo><language><languageTerm type="code" authority="rfc3066">en</languageTerm><languageTerm type="code" authority="iso639-2b">eng</languageTerm></language><physicalDescription><internetMediaType>text/html</internetMediaType><extent unit="figures">11</extent><extent unit="tables">1</extent></physicalDescription><abstract>Topography acts as a template for numerous landscape processes that include hydrologic, ecologic, and biologic phenomena. These processes not only interact with each other but also contribute to shaping the landscape as they influence geomorphic processes. We have investigated the effects of vegetation on thresholds for channel initiation and landform evolution using both analytical and numerical approaches. Vegetation is assumed to form a uniform ground cover. Runoff erosion is modeled based on a power function of excess shear stress, in which shear stress efficiency is inversely proportional to vegetation cover. This approach is validated using data. Plant effect on slope stability is represented by additional cohesion provided by plant roots. Vegetation cover is assumed to reduce sediment transport rates due to physical creep processes (rainsplash, dry ravel, and expansion and contraction of sediments) according to a negative exponential relationship. Vegetation grows as a function of both available cover and unoccupied space by plants and is killed by geomorphic disturbances (runoff erosion and landsliding) and wildfires. Analytical results suggest that in an equilibrium basin with a fixed vegetation cover, plants may cause a transition in the dominant erosion process at the channel head. A runoff erosion–dominated landscape, under none or poor vegetation cover, may become landslide dominated under a denser vegetation cover. The sign of the predicted relationship between drainage density and vegetation cover depends on the relative influence of vegetation on different erosion phenomena. With model parameter values representative of the Oregon Coast Range (OCR), numerical experiments conducted using the Channel Hillslope Integrated Landscape Development (CHILD) model confirm the findings based on the analytical theory. A highly dissected fluvial landscape emerges when surface is assumed bare. When vegetation cover is modeled, landscape relief increases, resulting in hollow erosion dominated by landsliding. Interestingly, our simulations underscore the importance of vegetation disturbances by geomorphic events and wildfires on the landscape structure. Simulated landscapes resemble real‐world catchments in the OCR when such disturbances are considered.</abstract><note type="additional physical form">Tab‐delimited Table 1.</note><subject><genre>keywords</genre><topic>ecogeomorphology</topic><topic>drainage density</topic><topic>vegetation dynamics</topic><topic>landscape evolution</topic><topic>channel initiation</topic></subject><relatedItem type="host"><titleInfo><title>Journal of Geophysical Research: Earth Surface</title></titleInfo><titleInfo type="abbreviated"><title>J. Geophys. Res.</title></titleInfo><genre type="journal">journal</genre><subject><genre>index-terms</genre><topic authorityURI="http://psi.agu.org/taxonomy5/0400">BIOGEOSCIENCES</topic><topic authorityURI="http://psi.agu.org/taxonomy5/0476">Plant ecology</topic><topic authorityURI="http://psi.agu.org/taxonomy5/1600">GLOBAL CHANGE</topic><topic authorityURI="http://psi.agu.org/taxonomy5/1625">Geomorphology and weathering</topic><topic authorityURI="http://psi.agu.org/taxonomy5/1800">HYDROLOGY</topic><topic authorityURI="http://psi.agu.org/taxonomy5/1824">Geomorphology: general</topic><topic authorityURI="http://psi.agu.org/taxonomy5/1815">Erosion</topic><topic authorityURI="http://psi.agu.org/taxonomy5/1851">Plant ecology</topic><topic authorityURI="http://psi.agu.org/taxonomy5/4400">NONLINEAR GEOPHYSICS</topic><topic authorityURI="http://psi.agu.org/taxonomy5/4430">Complex systems</topic></subject><identifier type="ISSN">0148-0227</identifier><identifier type="eISSN">2156-2202</identifier><identifier type="DOI">10.1002/(ISSN)2156-2202f</identifier><identifier type="CODEN">JGREA2</identifier><identifier type="PublisherID">JGRF</identifier><part><date>2005</date><detail type="volume"><caption>vol.</caption><number>110</number></detail><detail type="issue"><caption>no.</caption><number>F2</number></detail><extent unit="pages"><start>n/a</start><end>n/a</end><total>19</total></extent></part></relatedItem><identifier type="istex">42F66A3AE6097610532C602767F36846BA88A9BD</identifier><identifier type="DOI">10.1029/2004JF000249</identifier><identifier type="ArticleID">2004JF000249</identifier><accessCondition type="use and reproduction" contentType="copyright">Copyright 2005 by the American Geophysical Union.</accessCondition><recordInfo><recordContentSource>WILEY</recordContentSource></recordInfo></mods></metadata><serie></serie></istex></record>Pour manipuler ce document sous Unix (Dilib)
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