Temporal trends of vegetation indices on Pampa grasslands in Brazil and Uruguay

Detalhes bibliográficos
Autor(a) principal: Wagner, Ana Paula Luz
Data de Publicação: 2013
Outros Autores: Fontana, Denise Cybis, Fraisse, Clyde, Weber, Eliseu Jose, Hasenack, Heinrich
Tipo de documento: Artigo
Idioma: por
Título da fonte: Pesquisa Agropecuária Brasileira (Online)
Texto Completo: https://seer.sct.embrapa.br/index.php/pab/article/view/16008
Resumo: The objective of this work was to evaluate the reduction in the vegetative vigor of Pampa vegetation cover in Brazil and Uruguay, by identifying negative trends in images time series. The following were used: time series of NDVI/EVI images from the Modis sensor, from 2000 to 2011; images from soil moisture indices from the climate forecast system reanalysis; and precipitation data from meteorological stations. The study quantified linear and nonlinear trends in the NDVI and EVI series in grassland areas. With the Mann-Kendall monotonic trend, at 5% probability, 81.9% of the total area studied was significant with NDVI, and 74.8% with EVI; however, EVI showed superior contrast in the estimation of parameters. The results showed: highest negative signal in the west, with average values of R2>0.15, r<-0.3, and τ<-0.15 in the tendency of the vegetation indices; and decreasing tendency for NDVI, EVI, and rainfall, with lower mean soil moisture values. The negative trend of the vegetation indices, related to the combination of drought occurrence in surface soils with excessive grazing, indicates changes in the pattern of Pampa vegetation cover, with reduction in vegetative vigor.
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spelling Temporal trends of vegetation indices on Pampa grasslands in Brazil and UruguayTendências temporais de índices de vegetação nos campos do Pampa do Brasil e do Uruguainatural grasslands; EVI; Modis; NDVI; time seriescampos nativos; EVI; Modis; NDVI; séries temporaisThe objective of this work was to evaluate the reduction in the vegetative vigor of Pampa vegetation cover in Brazil and Uruguay, by identifying negative trends in images time series. The following were used: time series of NDVI/EVI images from the Modis sensor, from 2000 to 2011; images from soil moisture indices from the climate forecast system reanalysis; and precipitation data from meteorological stations. The study quantified linear and nonlinear trends in the NDVI and EVI series in grassland areas. With the Mann-Kendall monotonic trend, at 5% probability, 81.9% of the total area studied was significant with NDVI, and 74.8% with EVI; however, EVI showed superior contrast in the estimation of parameters. The results showed: highest negative signal in the west, with average values of R2>0.15, r<-0.3, and τ<-0.15 in the tendency of the vegetation indices; and decreasing tendency for NDVI, EVI, and rainfall, with lower mean soil moisture values. The negative trend of the vegetation indices, related to the combination of drought occurrence in surface soils with excessive grazing, indicates changes in the pattern of Pampa vegetation cover, with reduction in vegetative vigor.O objetivo deste trabalho foi avaliar a redução do vigor vegetativo da cobertura vegetal do Pampa do Brasil e do Uruguai, por meio da identificação de tendências negativas em séries temporais de imagens. Utilizaram-se séries temporais de imagens de NDVI/EVI do sensor Modis, de 2000 a 2011; imagens de índices de umidade do solo do “climate forecast system reanalysis”; e dados de precipitação pluvial de estações meteorológicas. O estudo quantificou tendências lineares e não lineares nas séries de NDVI e EVI, em áreas de campos. Na tendência monotônica de Mann-Kendall, a 5% de probabilidade, 81,9% da área total estudada foi significativa com o NDVI, e 74,8%, com o EVI; no entanto, o EVI apresentou contraste superior na estimativa dos parâmetros. Os resultados mostraram maior sinal negativo a oeste, com valores médios de R2>0,15, r<-0,3 e τ<-0,15 na tendência dos índices de vegetação, e tendência decrescente para NDVI, EVI e precipitação pluvial, com menores valores médios de umidade do solo. A tendência negativa dos índices de vegetação, relacionada à combinação da ocorrência de deficit hídrico em solos rasos com o sobrepastoreio, indica alterações no padrão de cobertura vegetal do Pampa, com redução do vigor vegetativo.Pesquisa Agropecuaria BrasileiraPesquisa Agropecuária BrasileiraCAPESWagner, Ana Paula LuzFontana, Denise CybisFraisse, ClydeWeber, Eliseu JoseHasenack, Heinrich2013-12-02info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://seer.sct.embrapa.br/index.php/pab/article/view/16008Pesquisa Agropecuaria Brasileira; v.48, n.9, set. 2013; 1192-1200Pesquisa Agropecuária Brasileira; v.48, n.9, set. 2013; 1192-12001678-39210100-104xreponame:Pesquisa Agropecuária Brasileira (Online)instname:Empresa Brasileira de Pesquisa Agropecuária (Embrapa)instacron:EMBRAPAporhttps://seer.sct.embrapa.br/index.php/pab/article/view/16008/12414https://seer.sct.embrapa.br/index.php/pab/article/downloadSuppFile/16008/10116info:eu-repo/semantics/openAccess2013-12-04T12:06:13Zoai:ojs.seer.sct.embrapa.br:article/16008Revistahttp://seer.sct.embrapa.br/index.php/pabPRIhttps://old.scielo.br/oai/scielo-oai.phppab@sct.embrapa.br || sct.pab@embrapa.br1678-39210100-204Xopendoar:2013-12-04T12:06:13Pesquisa Agropecuária Brasileira (Online) - Empresa Brasileira de Pesquisa Agropecuária (Embrapa)false
dc.title.none.fl_str_mv Temporal trends of vegetation indices on Pampa grasslands in Brazil and Uruguay
Tendências temporais de índices de vegetação nos campos do Pampa do Brasil e do Uruguai
title Temporal trends of vegetation indices on Pampa grasslands in Brazil and Uruguay
spellingShingle Temporal trends of vegetation indices on Pampa grasslands in Brazil and Uruguay
Wagner, Ana Paula Luz
natural grasslands; EVI; Modis; NDVI; time series
campos nativos; EVI; Modis; NDVI; séries temporais
title_short Temporal trends of vegetation indices on Pampa grasslands in Brazil and Uruguay
title_full Temporal trends of vegetation indices on Pampa grasslands in Brazil and Uruguay
title_fullStr Temporal trends of vegetation indices on Pampa grasslands in Brazil and Uruguay
title_full_unstemmed Temporal trends of vegetation indices on Pampa grasslands in Brazil and Uruguay
title_sort Temporal trends of vegetation indices on Pampa grasslands in Brazil and Uruguay
author Wagner, Ana Paula Luz
author_facet Wagner, Ana Paula Luz
Fontana, Denise Cybis
Fraisse, Clyde
Weber, Eliseu Jose
Hasenack, Heinrich
author_role author
author2 Fontana, Denise Cybis
Fraisse, Clyde
Weber, Eliseu Jose
Hasenack, Heinrich
author2_role author
author
author
author
dc.contributor.none.fl_str_mv
CAPES
dc.contributor.author.fl_str_mv Wagner, Ana Paula Luz
Fontana, Denise Cybis
Fraisse, Clyde
Weber, Eliseu Jose
Hasenack, Heinrich
dc.subject.por.fl_str_mv natural grasslands; EVI; Modis; NDVI; time series
campos nativos; EVI; Modis; NDVI; séries temporais
topic natural grasslands; EVI; Modis; NDVI; time series
campos nativos; EVI; Modis; NDVI; séries temporais
description The objective of this work was to evaluate the reduction in the vegetative vigor of Pampa vegetation cover in Brazil and Uruguay, by identifying negative trends in images time series. The following were used: time series of NDVI/EVI images from the Modis sensor, from 2000 to 2011; images from soil moisture indices from the climate forecast system reanalysis; and precipitation data from meteorological stations. The study quantified linear and nonlinear trends in the NDVI and EVI series in grassland areas. With the Mann-Kendall monotonic trend, at 5% probability, 81.9% of the total area studied was significant with NDVI, and 74.8% with EVI; however, EVI showed superior contrast in the estimation of parameters. The results showed: highest negative signal in the west, with average values of R2>0.15, r<-0.3, and τ<-0.15 in the tendency of the vegetation indices; and decreasing tendency for NDVI, EVI, and rainfall, with lower mean soil moisture values. The negative trend of the vegetation indices, related to the combination of drought occurrence in surface soils with excessive grazing, indicates changes in the pattern of Pampa vegetation cover, with reduction in vegetative vigor.
publishDate 2013
dc.date.none.fl_str_mv 2013-12-02
dc.type.none.fl_str_mv
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv https://seer.sct.embrapa.br/index.php/pab/article/view/16008
url https://seer.sct.embrapa.br/index.php/pab/article/view/16008
dc.language.iso.fl_str_mv por
language por
dc.relation.none.fl_str_mv https://seer.sct.embrapa.br/index.php/pab/article/view/16008/12414
https://seer.sct.embrapa.br/index.php/pab/article/downloadSuppFile/16008/10116
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Pesquisa Agropecuaria Brasileira
Pesquisa Agropecuária Brasileira
publisher.none.fl_str_mv Pesquisa Agropecuaria Brasileira
Pesquisa Agropecuária Brasileira
dc.source.none.fl_str_mv Pesquisa Agropecuaria Brasileira; v.48, n.9, set. 2013; 1192-1200
Pesquisa Agropecuária Brasileira; v.48, n.9, set. 2013; 1192-1200
1678-3921
0100-104x
reponame:Pesquisa Agropecuária Brasileira (Online)
instname:Empresa Brasileira de Pesquisa Agropecuária (Embrapa)
instacron:EMBRAPA
instname_str Empresa Brasileira de Pesquisa Agropecuária (Embrapa)
instacron_str EMBRAPA
institution EMBRAPA
reponame_str Pesquisa Agropecuária Brasileira (Online)
collection Pesquisa Agropecuária Brasileira (Online)
repository.name.fl_str_mv Pesquisa Agropecuária Brasileira (Online) - Empresa Brasileira de Pesquisa Agropecuária (Embrapa)
repository.mail.fl_str_mv pab@sct.embrapa.br || sct.pab@embrapa.br
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