Modeling potential distribution and carbon dynamics of natural terrestrial ecosystems: A case study of Turkey

We derived a simple model that relates the classification of biogeoclimate zones, (co) existence and fractional coverage of plant functional types (PFTs), and patterns of ecosystem carbon (C) stocks to long-term average values of biogeoclimatic indices in a time-and space-varying fashion from climate-vegetation equilibrium models. Proposed Dynamic Ecosystem Classification and Productivity (DECP) model is based on the spatial interpolation of annual biogeoclimatic variables through multiple linear regression (MLR) models and inverse distance weighting (IDW) and was applied to the entire Turkey of 780,595 km(2) on a 500 m x 500 m grid resolution. Estimated total net primary production (TNPP) values of mutually exclusive PFTs ranged from 108 +/- 26 to 891 +/- 207 Tg C yr(-1) under the optimal conditions and from 16 +/- 7 to 58 +/- 23 Tg C yr(-1) under the growthlimiting conditions for all the natural ecosystems in Turkey. Total NPP values of coexisting PFTs ranged from 178 +/- 36 to 1231 +/- 253 Tg C yr(-1) under the optimal conditions and from 23 +/- 8 to 92 +/- 31 Tg C yr(-1) under the growth-limiting conditions. The national steady state soil organic carbon (SOC) storage in the surface one meter of soil was estimated to range from 7.5 +/- 1.8 to 36.7 +/- 7.8 Pg C yr(-1) under the optimal conditions and from 1.3 +/- 0.7 to 5.8 +/- 2.6 Pg C yr(-1) under the limiting conditions, with the national range of 1.3 to 36.7 Pg C elucidating 0.1% and 2.8% of the global SOC value (1272.4 Pg C), respectively. Our comparisons with literature compilations indicate that estimated patterns of biogeoclimate zones, PFTs, TNPP and SOC storage by the DECP model agree reasonably well with measurements from field and remotely sensed data.