Decrease of terrestrial net primary production (NPP) in Southern Patagonia (Argentina) during the period 2000-2012

MARTÍNEZ PASTUR, G; DÍAZ DELGADO, R; LENCINAS, MV; KREPS, G; GUILLOZET, K; ANDERSON, CB; PERI, P

Congreso; IUFRO World Congress; 2015

Terrestrial net primaryproduction (NPP) is fixed as biomass and it has been directly influenced byclimate change during the last decades. This change did not present a cleartrend in southern Patagonia, and some authorsreported a decline in the global warming influence for the last decade. We usedsatellite data to estimate NPP (2000-2012) in seven forested and non-forestedecosystems, and compare them with the sea water temperature (SWT) obtained alsofrom satellite data (MODIS). NPP greatly changed with the vegetation ecosystems(mountain grasslands 320 grC.m2.yr-1, grasslands 390-450grC.m2.yr-1, and Nothofagusforests 500-820 grC.m2.yr-1), being systematicallylower during the studied period than 2000 (mountain grasslands -11%, grasslands-15% to -20%, forests -13% to -15%). SWT were related to NPP, where annual meantemperature presented r2=0.79, and also SWT is related to themultivariate ENSO index during summer with r2=0.58. The decrease in NPPcan trigger many ecosystem disturbances, changing the natural dynamics and decreasingcarbon uptake. A regional monitoring of NPP, both at field in long-term plotsand using satellite data, are essential to track changes in forest andgrassland productivity under the detected changing climate scenarios.