@InProceedings{PowellStil:2009:BiC3C4,
               author = "Powell, Rebecca L. and Still, Christopher J.",
          affiliation = "University of Denver, Colorado, USA and University of California, 
                         Santa Barbara, California, USA",
                title = "Biogeography of C3 and C4 vegetation in South America",
            booktitle = "Anais...",
                 year = "2009",
               editor = "Epiphanio, Jos{\'e} Carlos Neves and Galv{\~a}o, L{\^e}nio 
                         Soares",
                pages = "2935--2942",
         organization = "Simp{\'o}sio Brasileiro de Sensoriamento Remoto, 14. (SBSR)",
            publisher = "Instituto Nacional de Pesquisas Espaciais (INPE)",
              address = "S{\~a}o Jos{\'e} dos Campos",
             keywords = "remote sensing, C4 photosynthesis, biogeography, stable isotopes, 
                         MODIS continuous fields.",
             abstract = "The C3/C4 composition of vegetation is required for a diverse set 
                         of carbon cycle research, including inversion studies that use 
                         global CO2 and {\"a}13C atmospheric data, as well as work that 
                         requires the carbon isotope composition of biomass burning 
                         emissions. Here, we present continental maps of the abundance and 
                         distribution of C3 and C4 vegetation for South America. Our 
                         approach relies upon the near-universal restriction of C4 
                         photosynthesis to the herbaceous growth form and the differing 
                         performance of C3 and C4 plants in various temperature and 
                         radiation regimes. The MODIS Vegetation Continuous Fields (VCF) 
                         product provides detailed information on growth form composition 
                         (% tree, % herbaceous, and % bare) for each grid cell; 
                         precipitation and temperature variations are derived from station 
                         data climatologies; and crop type fractional coverage accounts for 
                         managed agro-ecosystems that may violate the natural climate 
                         constraints. A major limitation of the MODIS VCF product is that 
                         the vegetation layers do not directly correspond to the percent 
                         woody and percent herbaceous cover layers that are needed to 
                         accurately derive C3/C4 composition of vegetation cover. To 
                         address this issue, we develop a rules-based algorithm to separate 
                         shrubs and true herbaceous cover from the MODIS herbaceous (i.e., 
                         non-tree vegetation) layer using the Global Land Cover 2000 
                         dataset for South America. The {\"a}13C content of vegetation in 
                         South America is then estimated based on the C3/C4 composition in 
                         each land grid cell, assuming constant values of -27 and -12 for 
                         C3 and C4 plant biomass, respectively.",
  conference-location = "Natal",
      conference-year = "25-30 abr. 2009",
                 isbn = "978-85-17-00044-7",
             language = "en",
         organisation = "Instituto Nacional de Pesquisas Espaciais (INPE)",
                  ibi = "dpi.inpe.br/sbsr@80/2008/11.17.20.20",
                  url = "http://urlib.net/ibi/dpi.inpe.br/sbsr@80/2008/11.17.20.20",
           targetfile = "2935-2942.pdf",
                 type = "Floresta e Vegeta{\c{c}}{\~a}o",
        urlaccessdate = "01 maio 2024"
}