Earthworm communities of tropical agroecosystems : origin, structure and influence of management practices

Data of 145 and 69 earthworm communities from managed and natural ecosystems, respectively, of four continents and 15 tropical countries were analysed. The aim of the study was to separate the influence of phylogenetic, environmental and agricultural factors on the structure of earthworm communities in agroecosystems, and to evaluate their relative importance in the whole soil macrofauna community. Earthworms comprise 40-90% of macrofaunal biomass in most ecosystems except for annually cropped systems. Three major conclusions were drawn from the analysis of community structure (regional analysis): (i) crops were, independently of region, characterized by a loss of native species and by the dominance ofexotic endogeics; (ii) pastures were highly heterogenous in terms of native or exotic species dominance; (iii) native species survived better in management ecosystems ofIndia and Africa than in Mexico-Central America.