IMBIV   05474
INSTITUTO MULTIDISCIPLINARIO DE BIOLOGIA VEGETAL
Unidad Ejecutora - UE
artículos
Título:
Late Holocene shift in C4 species range in central Argentina.
Autor/es:
SILVA, L.C.R; GIORGIS, M.A.; ANAND, M.; ENRICO, L.; PÉREZ-HARGUINDEGUY, N.; FALCZUK, V.; TIESZEN, L.; CABIDO, M.R.
Revista:
PLANT AND SOIL
Editorial:
SPRINGER
Referencias:
Año: 2011 vol. 349 p. 261 - 279
ISSN:
0032-079X
Resumen:
Aim Millennial-scale biogeographic changes arewell understood in many parts of the world, butlittle is known about long-term vegetation dynamicsin subtropical regions. Here we investigate shifts inC3/C4 plant abundance occurred in central Argentinaduring the past few millenniaMethods We determined present day soil organicmatter δ13C signatures of grasslands, shrublands andwoodlands, containing different mixtures of C3 andC4 plants. We measured past changes in the relativecover of C3/C4 plants by comparing δ13C values in soil profiles with present day δ13C signatures. Weanalyzed 14C activity in soil depths that showed majorchanges in vegetation.Results Present day relative cover of C3/C4 plantsdetermines whole ecosystem δ13C signatures integratedas litter and superficial soil organic matter (R2=0.78; p<0.01). Deeper soils show a consistent shift inδ13C, indicating a continuous replacement of C4 byC3 plants since 3,870 (±210) YBP. During this period,the relative abundance of C3 plants increased 32%(average across sites) with significant changes beingobserved in all studied ecosystems.Conclusions Our results show that C4 species were moreabundant in the past, but C3 species became dominantduring the late Holocene. We identified increases in therelative C3/C4 cover in grasslands, shrublands andwoodlands, suggesting a physiological basis for changesin vegetation. The replacement of C4 by C3 plantscoincided with changes in climate towards colder andwetter conditions and could represent a climaticallydriven shift in the C4 species optimum range.