Decreasing of terrestrial net primary production (NPP) in Southern Patagonia (Argentina) during the period 2000-2013.

G MARTÍNEZ PASTUR; R DIAZ DELGADO; MV LENCINAS; PL PERI

Tartu

Conferencia; IUFRO Landscape Ecology Conference; 2015

Tartu University

Terrestrial Net Primary Production (NPP) is fixed as biomass and it is directly influenced by climate change during the last decades. However, such trends in southern Patagonia are not clear, and some authors reported a decline in this region´s temperature in the last decade. We used NPP data product derived from MODIS satellite images from 2000 to 2013 in seven forested and non-forested ecosystems, and regressed them with the sea surface temperature (SST), obtained also from MODIS images. NPP was different between vegetation types (mountain grasslands 320 grC.m2.yr-1, grasslands 390-450 grC.m2.yr-1, and Nothofagus forests 500-820 grC.m2.yr-1), and decreased over the studied period compared to year 2000 (mountain grasslands -11%, grasslands -15% to -20%, forests -13% to -15%). SST, measured as annual mean temperate, was highly related to NPP (r2=0.79), and also SST is related to the multivariate ENSO index during summer (r2=0.58). The decrease in NPP could trigger many ecosystem alterations, changing natural dynamics and decreasing carbon uptake. Regional monitoring of NPP, both in long-term field plots and with satellite data, is essential to track changes in forest and grassland productivity under the novel climate change scenarios detected here for Tierra del Fuego.