ABSTRACT
Diversity and dynamics of a high sub-Andean forest from Northern Andes, Colombia. The sub-Andean forests are characterized by a high biodiversity, but little is known about their natural dynamics. In order to generate new information, this study assessed two permanent plots of one hectare each, in the Northern Andean area of the Western Cordillera, Colombia. Methodology included the evaluation of diversity patterns, above ground biomass (AGB) dynamics, and mortality and recruitment rates. Besides, we used the Fisher´s Alpha index to calculate species diversity. Forest dynamics and AGB were evaluated in both plots by means of three censuses carried out within a nine years period. In total, we found 1 664 individuals with diameter at breast height (DBH)≥10cm belonging to 222 species, 113 genera and 60 families. Mean species richness was of 156 species/ha and a mean Fisher´s Alpha index of 56.2/ha. The mortality rate was 0.88% and recruitment was 1.16%, which did not allow to lay any external effect of global warming or climate change on individual forest dynamics. However, the mean AGB was 243.44±9.82t/ha, with an annual average increase of 2.9t/ha, a higher value than the one reported in other studies of high sub-Andean forests, which suggests that equilibrium in terms of the AGB have not yet been reached. Besides, according to field observations, a recovery process, from a disturbance that occurred in the past, might be on his way. Rev. Biol. Trop. 60 (2): 943-952. Epub 2012 June 01.
Los bosques sub-Andinos poseen alta diversidad biológica, de los cuales poco se conoce sobre su dinámica natural. Se evaluaron patrones de diversidad y biomasa, tasas de mortalidad y reclutamiento en dos parcelas permanentes de una hectárea cada una, establecidas en bosques en altitudes entre los 2 000-2 200msnm, en la vertiente Oriental de la cordillera Occidental del norte de los Andes en Colombia. Se determino diversidad de especies mediante el índice alpha de Fisher, la dinámica del bosque se evaluó mediante tres censos durante nueve anos. En total, se hallaron 1 964 individuos con un diámetro a la altura del pecho DAP≥10cm. pertenecientes a 222 especies, 113 géneros y 60 familias. La riqueza media de especies fue de 156 especies por hectárea y un índice alpha medio de Fisher de 56.2/h. Las tasas de mortalidad y reclutamiento fueron de 0.88% y 1.16% respectivamente, lo cual no indica que se presente un efecto externo proveniente del calentamiento global sobre la dinámica del bosque. La biomasa aérea promedio fue de 243.44±9.82tn/ha con un incremento anual promedio de 2.9ton/ha, valor superior a los reportados, lo cual sugiere que el equilibrio para este bosque no se ha alcanzado. De acuerdo con las observaciones de campo, este bosque parece estar recuperándose de una alteración pasada.