The heterogeneity of the vegetation in arid and semiarid Patagonia: an analysis using AVHRR/NOAA Satellite Imagery

AGUIAR, M.R.; PARUELO, J. M.; GOLLUSCIO, R.A.; LEÓN, R.J.C.; BURKART, S.E.; PUJOL, G.

Annali di botanica

Universidad Sapienza de Roma

Lugar: Roma; Año: 1988 vol. 46 p. 103 - 114

0365-0812

Arid and semiarid Patagonia occupies a large portion of Argentina between 40º and 55º S approximately. Its floristic districts were defined in 1956, but only in the last decade have studies on a smaller scale been carried out. The present paper shows the results of an objective analysis of the heterogeneity of a 230.000 km2 area, which includes the principal Patagonian vegetation units, using AVHRR/NOAA imagery. Available spectral data was used to calculate the normalized difference vegetation index (NDVI), a measure of existing green biomass. A polar ordination was carried out based on NDVI values for 6 datasets, from 127 locations of the study area. The results of the ordination confirmed some of the already described floristic boundaries, while they allowed to postulate a new subdivision in one of these units. The NDVI allowed to analyse the seasonal dinamics of green biomass in the various vegetation units. Results showed two patterns of variation of NDVI values related to rainfall distribution along the year.