INVESTIGADORES
VILLALBA Ricardo
artículos
Título:
Precipitation variability and landslide occurrence in a subtropical mountain ecosystem of NW Argentina
Autor/es:
PAOLINI, L.; VILLALBA, R.; GRAU, H.R.
Revista:
Dendrochronologia
Editorial:
Elsevier
Referencias:
Lugar: Amsterdam; Año: 2005 vol. 22 p. 175 - 180
ISSN:
1125-7865
Resumen:
Landslides are common on the steep slopes of the
subtropical montane forests in Northwestern (NW) Argentina (Yungas).
Instrumental and tree-ring records from this region indicate that rainfall has
increased during the second half of the 20th century and there has also been an
increase in landslide events.We used dendroecological techniques to date the
occurrence of landslides during the past 50 years and examine the relationships
with regional precipitation trends. Alnus
acuminata H.B.K. is the dominant species in the upper montane forest and
colonizes the bare areas exposed by landslides. Landslide dating was based on
the identification of suppression-release patterns in ring-width series from
trees growing along the landslide scarps, in combination with age determination
of trees growing on the landslide failure or depositional surfaces. We cored A. acuminata in three areas that span
the latitudinal range of the montane forest in NW Argentina: Los Sosa (27°S),
Hualinchay (26°S) and Yala (24°S). The results show that landslide occurrence
(and therefore probability) is more frequent during summers with abundant
rainfall. As General Circulation Models for subtropical South America predict
an increase in summer precipitation during the 21st century, increased precipitation
could induce changes in landslide regime that would lead to important
environmental changes in these montane ecosystems.