The peregrine earthworm Pontoscolex corethrurus in the East coast of Costa RicaThe 7th international symposium on earthworm ecology · Cardiff · Wales · 2002

Abstract

Summary Sampling of earthworm communities was performed in the Caribbean coast of Costa Rica at 8 sites to assess the distribution of the peregrine pantropical species Pontoscolex corethrurus and its relationships with native species depending on the type of land use. P. corethrurus was largely dominant at each site and in almost all habitat types. Density was in the range of 143 to 182 ind.m−2. P. corethrurus was absent from only one primary forest site where only native species could be found. In banana plantations, the density reached maximum of ca. 361 ind.m−2. In all sites, an increase of this species corresponds significantly with a reduction of the rest of the earthworm fauna except for Dichogaster sp. Where P. corethrurus was absent, density of other species reached 34.4 ind.m−2. In southern Costa Rica, human immigration and sustained activities probably favoured the establishment of P. corethrurus. This species became dominant, even in remaining plots of primary forests. In contrast, the species has not yet penetrated the large primary forest of the north-east of the country.