Six years of solar UV-B manipulations affect growth of Sphagnum and vascular plants in a Tierra del Fuego peatland

ROBSON, M.; VERONICA ANDREA PANCOTTO; BALLARÉ, C. A.; SALA, O. E.; SCOPEL, A. L.; CALDWELL, M. M.

NEW PHYTOLOGIST

WILEY-BLACKWELL PUBLISHING, INC

Año: 2003 vol. 160 p. 379 - 389

0028-646X

? Tierra del Fuego is subject to increases in solar UV-B radiation in the austral spring and summer due to ozone depletion. ? Plastic films were used to filter solar UV-B radiation over peatland plots through six field seasons, resulting in near-ambient ( c . 90%) and reduced ( c . 17%) solar UV-B treatments. ? As in the first three field seasons of treatments, near-ambient UV-B caused reduced height growth but had no effect on biomass production of the moss Sphagnum magellanicum. It reduced leaf and rhizome growth of Tetroncium magellanicum . Height growth and morphology of Empetrum rubrum and Nothofagus antarctica were only affected by solar UV-B during the fourth to sixth field seasons. There was also a decrease in Tetroncium leaf nitrogen under near-ambient UV-B. ? Growth of Sphagnum was less affected than that of most emergent vascular plants. This enabled the Sphagnum mat to engulf more Nothofagus , and limit the escape of Empetrum under near-ambient UV-B. Yet, differences in the response of species to solar UV-B were not expressed as changes in plant community composition.