Linking modern pollen accumulation rates to biomass: Quantitative vegetation reconstruction in the western Klamath Mountains, NW California, USA

Quantitative reconstructions of vegetation abundance from sediment-derived pollen systems provide unique insights into past ecological conditions. Recently, the use accumulation rates (PAR, grains cm ?2 year ?1 ) has shown promise as a bioproxy for plant abundance. However, successfully reconstructing region-specific dynamics using PAR requires that accurate assessments deposition processes be quantitatively linked to spatially-explicit measures Our study addressed these methodological challenges. Modern and data were obtained seven lakes in western Klamath Mountains, California. To determine how best calibrate our PAR-biomass model, we first calculated spatial area where composition patterning is recorded by changes signal two metrics. These metrics an assemblage-level relevant source (aRSAP) derived extended R-value analysis ( sensu Sugita, 1993) taxon-specific (tRSAP) regression Jackson, 1990). knowledge, aRSAP tRSAP have not been directly compared. We found estimated smaller some taxa (e.g. circular with 225 m radius Pinus) than (a 625 radius). fit linear models relate values modern lake sediments empirical, distance-weighted estimates aboveground live biomass (AGL dw both distances. In cases, PARs major tree – Pseudotsuga, Pinus, Notholithocarpus, TCT (Taxodiaceae, Cupressaceae, Taxaceae families) statistically significant reasonably precise estimators contemporary AGL . predictions weighted distance defined tended more precise. The relative root-mean squared error was 9% compared 12% tRSAP. results demonstrate calibrated relationships robust method infer biomass.