Dendroecology of Nothofagus on flooded lakeshores caused by Perito Moreno Glacier, Patagonia, Argentina

GUERRIDO, CLAUDIA; AMOROSO, MARIANO; RODRÍGUEZ CATÓN, MILAGROS; VILLALBA, RICARDO

Conferencia; Third American Dendrochronology Conference ? AmeriDendro2016; 2016

Perito Moreno Glacier obstructed the Canal de Los Témpanos causing flooding of Lago Argentino since 1936. These floods could be considered large-scale events, according to stand dynamic theory, removing vegetation and periodically altering forest succession. While forest recruitment is well documented for avalanches, landslides, fires, etc. it is not the same in the case of floods. The aim of this study was to document through dendrochronology and spatial statistics, forest recolonization of the flooded shores of Lago Argentino. A total of 780 seedlings were sampled in 10 plots. Species and individual position were marked in each plot. Height and diameter in the base (DAB) were measured. Samples were taken from seedlings with > 5 cm DAB using increment borer. Smaller samples were removed and cut transversely between root and stem. Samples were processed using conventional techniques in dendrochronology. Dates were visually established. Three years after the flood of 1988, Embothrium coccineum, and three Nothofagus were present. Maximum age of saplings recruited was 17 years (average 5-10 years), considering 2004 as unified sampling date for all plots. Seedlings were detected with a clustered spatial pattern in 100% of the plots, using univariate L function. Applying the same function per species, 100%-clustered patterns were also detected. Using Lcross bivariate function, significant interaction between species occurred in 100% of the plots, where at least two species were present. In conclusion, the age of recruitment coincided with the last large-scale flooding of 1988. There are 6 species of trees in the area, 4 of them colonized the shore. Clustering patterns could be determined by soil and site conditions.