Abstract

MOMO, Fernando R.  and  FALCO, Liliana B.. Spatio-temporal dynamics of a multi-specific earthworm population in an oak woodland. Acta Zool. Mex [online]. 2010, vol.26, n.spe2, pp.203-2010. ISSN 2448-8445.

We studied the spatial dynamics of endogeic earthworms in a Quercus robur forest. Samples were taken using a 30 point grid every three months during a year plus a summer. Growth rates were estimated for each point based on abundance data. Abundances appeared to be correlated in the direction NW-SE showing a net movement of the organisms to the SE region of the studied field. The migration speed of earthworms was 1.2 m month^-1. We fitted the spatial dynamics to several growth mathematical models; the most accurate models were the logistic model of Smith, that is a model with physiological constraints, and the non-symmetric logistic equation, that considers inter-specific competition. The models revealed a significant non-hierarchic diffuse competition and a low rate of individual resource consumption. Moreover, growth rates were high at low population densities but remained roughly constant at densities above 20 individuals m^-2.

Keywords : Oligochaetes; spatial and temporal dynamics; correlation; growth models.

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