Coupling of remote sensing, field campaign, and mechanistic and empirical modeling to monitor spatiotemporal carbon dynamics of a Mediterranean watershed in a changing regional climate

The aim of this study was to simulate impacts of regional climate change in the 2070s on carbon (C) cycle of a Mediterranean watershed combining field measurements, Envisat MERIS and IKONOS data, and the Carnegie Ames Stanford Approach model. Simulation results indicated that the present total C sink status (1.36 Mt C year −1 ) of Mediterranean evergreen needleleaf forest, grassland and cropland ecosystems is expected to weaken by 7.6 % in response to the climate change in the 2070s (Mt = 10 12 g). This decreasing trend was mirrored in soil respiration ( R H ), aboveground and belowground net primary production (NPP), NEP, and net biome production (NBP). The decrease in NEP in the 2070s was the highest (21.9 %) for mixed forest where the smallest present C sink of 0.03 Mt C year −1 was estimated. The average present net ecosystem production (NEP) values were estimated at 110 ± 15, 75 ± 19, and 41 ± 25 g C m −2 years −1 in forest, grassland, and cropland, respectively, with a watershed-scale mean of 95 ± 30 g C m −2 years −1 . The largest present C sink was in grassland, with a total C pool of 0.55 Mt C year −1 , through its greater spatial extent.