Abstract

GIRALDO MENDOZA, Alfredo  and  ARELLANO CRUZ, Germán. Resiliencia de la Comunidad Epígea de Coleoptera en las Lomas De Lachay después del Evento El Niño 1997-98. Ecol. apl. [online]. 2003, vol.2, n.1, pp.59-68. ISSN 1726-2216.

The present study describes the resilience of a epigeic beetle assemblage inhabiting in a lomas formations in the face of the changes caused by the occurrence of the El Niño 1997-98. The beetle assemblage was evaluated 17 times since 1998 until 2002 using pitfall traps that were systematically distributed in a mixed area of herbaceous lomas and type park lomas in the Lachay National Reserve. For detecting the manifestations of the resilience across the time, the following measures were employed: abundance, richness, diversity, composition and relative abundance of the morphospecies, relative abundance of the guilds, carabidae:tenebrionidae proportion (C:T) and a percentage index to measure seasonality (I.P.). The most important manifestations of the resilience were detected comparing the evaluations carried out in the 1st and 2nd sampling of every year. For the 1st sampling evaluations, progressive tendencies of decrease of the diversity, increase of the relative abundance of detritivores and increase of the relative abundance of darkling beetles were observed. For the 2nd sampling, marked differences were observed between the 1998´s evaluation and the evaluations of later years, these were a marked decrease in the diversity, an increase in the relative abundance of omnivores and an increase in the relative abundance of ground beetles. The abundance and the richness lacked clear patterns of resilience. Also, the resilience meant a progressive increase of the seasonality, as it was indicated by the I.P. values calculated with the diversity and the C:T proportion. The most effective measure of resilience was the C:T proportion, for that reason the use of this kind of proportions is recommended for the evaluation of perturbations.

Keywords : Beetle epigeic assemblage; resilience; El Niño 1997-98; lomas formations; Lachay National Reserve.

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