Resumen

RICHARDSON, BARRY J  y  ARIAS-BOHART, ELIZABETH T. Why so many apparently rare beetles in Chilean temperate rainforests?. Rev. chil. hist. nat. [online]. 2011, vol.84, n.3, pp. 419-432. ISSN 0716-078X.  doi: 10.4067/S0716-078X2011000300009.

Species abundance curves were calculated from data sets collected by fogging 52 trees in Nothofagus forest (~46000 specimens) and 24 trees in Araucaria forest (~15000 specimens) in Chile. Neither data set fitted the standard species abundance models. Like similar data sets collected from tropical forests, there were too many species represented by single specimens. The proposal that these were vagrants normally found on other tree species was not supported as, unlike tropical forests, Nothofagus forests are not diverse, often consisting of single species stands. Examination of three assumptions of the most parsimonious equilibrium models showed them to be false. Between them the observations of undersampling bias, community disequilibria and combining data from different feeding guilds with different species abundance curves are likely to be sufficient to explain the divergence of data for large speciose beetle communities from the predictions of any of the equilibrium models. Until these three factors can be fully accounted for and residual divergence detected, there is no necessity to propose further, more complex, mechanisms to explain such data sets. Estimated values of alpha and Simpson D were shown to be strongly sample size dependent, affecting their value as estimators of biological diversity.

Palabras clave : species abundance curves; biodiversity estimation; body size and density.