Succession of ground-dwelling beetle assemblages after fire in three habitat types in the Andean forest of NW Patagonia, Argentina

SASAL, YAMILA; RAFFAELE, ESTELA; FARJI-BRENER, ALEJANDRO GUSTAVO

JOURNAL OF INSECT SCIENCE

University of Wisconsin Digital Collections Center and the UW-Madison Libraries' Office of Scholarly Communication and Publishing

Lugar: Wisconsin; Año: 2010 vol. 10 p. 1 - 17

1536-2442

Wildfires are one of the major disturbances in the dynamics of forests and shrublands. However,little is known about their effects on insect communities that contribute to faunal biodiversity andplay key roles in the ecosystem's dynamics. An intense and widespread fire occurred in 1999 inthe Nahuel Huapi National Park in the Andean forest in northern Patagonia, Argentina. This fireaffected adjacent, but different, habitat types. After the fire, beetle abundance, species richnessand assemblage composition were compared among three habitats that were structurally differentbefore the fire. These habitats were: 1) evergreen forest dominated by Nothofagus dombeyi(Mirb.) Oerst. (Fagales: Nothofagaceae), 2) a mixed forest of the evergreen conifer Austrocedrus chilensis (D. Don) Pic. Serm. and Bizzarri (Pinales: Cupressaceae) and N. dombeyi and 3) a shrubland with a diverse community of shrub species. The relationship between beetle diversity and vegetation structure was investigated over three consecutive years. Ground beetles were collected by pitfall traps, and plant species richness, vegetation cover, and height were measured. Beetle communities varied more over years between habitats during the early regeneration after fire. There was a shift in beetle assemblage composition with time after the fire in all habitat types, probably due to similar colonization rates and microclimatic conditions. Therefore, beetle succession was more influenced by recolonization and survivorship, accompanied by climatic conditions and recovery rate of plant communities over time, than it was influenced by pre-fire habitat conditions. These results suggest that in NW Patagonia, wildfire can have a substantial, short-term impact on beetle abundance and species composition. The pre-fire conditions of each habitat type determined the structure of post-fire communities of plants but not beetle assemblages. Wildfires produce simplification and homogenization of habitat types, and this was reflected by beetle diversity.