Estimates of soil carbon concentration in tropical and temperate forest and woodland from available GIS data on three continents

LADD B.; LAFFAN S.W.; AMELUNG W.; PERI P.L.; SILVA L.C.R; GERVASSI P.; BONSER S.P.; NAVALL M.; SHEIL D.

Global Ecology and Biogeography

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2013 vol. 22 p. 461 - 469

1466-822X

1. Leaf area index (LAI), a measure of canopy density, is a key variable for modelling and understanding productivity, water use and various stand level processes in forest ecosystems.  Nevertheless LAI often varies considerably with phenology and disturbance patterns so alternative, complementary approaches to quantifying stand level processes should also be considered.  The carbon isotope composition of soil organic matter (ä13CSOM) provides a time-integrated, productivity-weighted measure of physiological processes, and reflects biomass deposition from annual to decadal time scales. 2. Our aim was to explore how well LAI correlates with ä13CSOM across biomes. 3. Using a global data set spanning tropical, temperate and boreal forest and woodland we assess the strength of the correlation between LAI and ä13CSOM as well as climatic variables derived from the WorldClim database.  4. We found that LAI is tightly correlated to ä13CSOM, solar radiation (Q) and mean temperature of the wettest quarter of the year (MTWQ).  5. Synthesis. Our results demonstrate that ä13CSOM values can provide spatially explicit and accurate estimates of LAI and therefore key aspects of ecosystem, i.e. productivity and water use at the ecosystem scale. While ä13CSOM has traditionally been used to reconstruct the relative abundance of C3 vs. C4 species, the results of this study demonstrate that within stable C3- or C4- dominated areas ä13CSOM can provide additional insights into ecosystem functioning.  The fact that LAI is strongly correlated to ä13CSOM may allow for a more nuanced interpretation of paleosol 13C values that will enhance our capacity to ecologically interpret the fossil record.