IMASL   20939
INSTITUTO DE MATEMATICA APLICADA DE SAN LUIS "PROF. EZIO MARCHI"
Unidad Ejecutora - UE
artículos
Título:
Variations in Anarthrophyllum rigidum radial growth, NDVI and ecosystem productivity in the Patagonian shrubby steppes
Autor/es:
SRUR, A.M.; VILLALBA, R.
Revista:
PLANT ECOLOGY
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2011 vol. 212 p. 1841 - 1854
ISSN:
1385-0237
Resumen:
The lack of long-term records of productivity
is a critical limitation to the study of ecosystem
dynamics. Annual rings, a measure of growth in
woody species, are a useful tool to document
ecosystem dynamics. Time series of the Normalized
Difference Vegetation Index (NDVI) provide estimates
of ecosystem productivity through satellitederived
data on the fraction of photosynthetic active
radiation absorbed by vegetation. In the Patagonian
steppes, we relate changes in NDVI to interannual
variations in the radial growth of the shrub Anarthrophyllum
rigidum. A widely distributed network of
15 ring-width chronologies of A. rigidum was used to
estimate changes in NDVI across the Patagonia
steppe (35?50S). In most sites, interannual variations
in shrub growth and NDVI are regulated by
winter precipitation. The water accumulated in the
soil during winter is used by A. rigidum during the
growing season, concurrent with the maximum NDVI
values. At 10 from the 15 selected sites, variations in
the radial growth of A. rigidum explained between 23
and 62% of the total variance in seasonal NDVI,
suggesting that the A. rigidum growth at some sites
provides good estimates of productivity in the
Patagonian shrubby steppes during the growing
season. However, we were unable to determine clear
relationships between radial growth and NDVI at
high-elevation mountainous sites or where intensive
grazing by sheep masked the effect of climate
variability on shrub growth. We conclude that
dendrochronological methods can complement other
estimates to reconstruct variations of productivity,
supplementing and extending the few short records
available in the Patagonian steppe.