MACNBR   00242
MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
artículos
Título:
Nurse logs: an ecological strategy in a Late Paleozoic forest from the southern Andean region
Autor/es:
CÉSARI, S. N.; BUSQUEST, P.; COLOMBO, F.; MÉNDEZ BEDIA, I.; LIMARINO, C. O.
Revista:
GEOLOGY
Editorial:
GEOLOGICAL SOC AMER, INC
Referencias:
Año: 2010 vol. 38 p. 295 - 298
ISSN:
0091-7613
Resumen:
Decaying logs on the forest fl oor can act as nurse logs for new
seedlings, helping with the regeneration of the vegetation. Fossil evidence
of this ecological strategy is exceptionally well preserved in
the Argentinean Andes, where an ~300 m.y. old permineralized forest
was found at 3000 m elevation in San Juan Province. The fossil
trunks, some of them in life position, are intercalated between volcanic
rocks and sediments deposited in fl ooded environments (probably
coastal lagoons). More than 100 specimens studied allow us to suggest
the dominance of only one tree species in the forest. The fi rst issue
of the research was to determine the means used by the vegetation
to survive in such adverse environmental conditions. Fossil evidence
supports the hypothesis of regeneration via nurse logs. Little rootlets
preserved inside the wood of several specimens indicate that seedlings
developed on these logs. Important additional information provided
by the fossils is the presence of aerenchymatic tissue in the rootlets.
Aerenchyma tissue is a common feature developed in plants living
in fl ooded environments; therefore its recognition in the fossil forest
helps in the ecological interpretation.