Abstract:
"We used a soil water simulation model and remotely sensed data to
study the long-term dynamics of transpiration, evaporation, drainage and net
primary production across a precipitation gradient in Northwestern Patagonia
(Argentina). The proportion of precipitation transpired, the precipitation use
efficiency and the transpiration use efficiency were constant across the
gradient that covered a
... range of 150 to 600 mm. The proportion of water
evaporated was higher than the proportion drained at the driest extreme of the
gradient. The opposite relationship was observed at the wet extreme. Two
important characteristics of arid-semiarid systems dominated by winter
precipitation emerged from our analyses: the importance of drainage losses and
the asynchrony between evaporation and transpiration fluxes. These
characteristics of the water dynamics influence the relative abundance of plant
functional types and are crucial to generate heterogeneity at the landscape
level. The coefficient of variation (CV) of transpiration, evaporation and ANPP
was, in general, lower than the CV of annual precipitation. This pattern
suggests a buffering capacity of the ecosystem. The ecosystem would be able to
damp at the functional level inter-annual changes in the availability of
resources". To read the full article, access http://www.kluweronline.com and in
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