Resumo

BALDASSINI, Pablo; VOLANTE, José N; CALIFANO, Laura M  e  PARUELO, José M. Regional characterization of the structure and productivity of the vegetation of the Puna using MODIS images. Ecol. austral [online]. 2012, vol.22, n.1, pp.22-32. ISSN 1667-782X.

The Puna is a semi-arid region located over 3300 m.a.s.l. in the northwestern portion of Argentina. Previous regional studies in Puna focused on the description of the floristic heterogeneity of relatively small portions of the territory. No integrative descriptions of the phisiognomy and functioning of the Puna ecosystems, two keys aspects for development of management actions, have been produced. In this article we generated a map of physonogmic types and we characterized above-ground net primary production (ANPP) of the different classes defined over an area of 69210 km2. The methodology to characterize vegetation structure (physiognomic units) combines remotely sensed data from MODIS sensor with field observations. Further, we applied biophysical models and satellite information to estimate ANPP. Among the classes with more than 5% of plant cover, shrub steppes (both sparse and dense) occuppied most of the area (45%). Dense grass steppes covered less than 1%. Bare soil covered most that 30% of the area, followed by Salt flats (8.15%). The most productive physiognomic type was the dense grass steppe (ANPP = 3900 kg DM.ha^-1.year^-1), while the sparse shrub steppe unit presented the lowest values (ANPP = 472 kg DM.ha^-1.year^-1). The remaining physiogmomic types presented ANPP values lower than 1000 kg DM.ha^-1.year^-1.

Palavras-chave : Ecoregions; Spectral indixes; Remote sensing; Forage resources; Ecosystem functioning.

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