title: Human and environmental controls over aboveground carbon storage in Madagascar.
abstract: BACKGROUND
  Accurate, high-resolution mapping of aboveground carbon density (ACD, Mg C ha-1) could provide insight into human and environmental controls over ecosystem state and functioning, and could support conservation and climate policy development. However, mapping ACD has proven challenging, particularly in spatially complex regions harboring a mosaic of land use activities, or in remote montane areas that are difficult to access and poorly understood ecologically. Using a combination of field measurements, airborne Light Detection and Ranging (LiDAR) and satellite data, we present the first large-scale, high-resolution estimates of aboveground carbon stocks in Madagascar.
  
  
  RESULTS
  We found that elevation and the fraction of photosynthetic vegetation (PV) cover, analyzed throughout forests of widely varying structure and condition, account for 27-67% of the spatial variation in ACD. This finding facilitated spatial extrapolation of LiDAR-based carbon estimates to a total of 2,372,680 ha using satellite data. Remote, humid sub-montane forests harbored the highest carbon densities, while ACD was suppressed in dry spiny forests and in montane humid ecosystems, as well as in most lowland areas with heightened human activity. Independent of human activity, aboveground carbon stocks were subject to strong physiographic controls expressed through variation in tropical forest canopy structure measured using airborne LiDAR.
  
  
  CONCLUSIONS
  High-resolution mapping of carbon stocks is possible in remote regions, with or without human activity, and thus carbon monitoring can be brought to highly endangered Malagasy forests as a climate-change mitigation and biological conservation strategy.
authors.affiliation: Department of Global Ecology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA USA. gpa@stanford.edu.
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Asner
authors.forename: John K
authors.initials: JK
authors.lastname: Clark
authors.forename: Joseph
authors.initials: J
authors.lastname: Mascaro
authors.forename: Romuald
authors.initials: R
authors.lastname: Vaudry
authors.forename: K Dana
authors.initials: KD
authors.lastname: Chadwick
authors.forename: Ghislain
authors.initials: G
authors.lastname: Vieilledent
authors.forename: Maminiaina
authors.initials: M
authors.lastname: Rasamoelina
authors.forename: Aravindh
authors.initials: A
authors.lastname: Balaji
authors.forename: Ty
authors.initials: T
authors.lastname: Kennedy-Bowdoin
authors.forename: Léna
authors.initials: L
authors.lastname: Maatoug
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Colgan
authors.forename: David E
authors.initials: DE
authors.lastname: Knapp