Résumé
Little information is available on earthworm distribution and diversity in the State of Parana, southern Brazil. Earthworm abundance and species diversity was evaluated in four land use systems near Jaguapita, (Parana); where pastures are being converted to soybean and sugarcane. Samples were taken during the rainy and dry seasons of 2004 and 2005 in eight sites: two old degraded pastures, an old pasture being converted to row cropping, two grain crop fields, two sugarcane fields and a native forest fragment. Twenty-five 25 x 25 cm soil blocks were taken at each site, 20 of them to 10 cm and five to 30 cm depth. Earthworms were manually sorted from the soil and preserved in formaldehyde. Earthworm species found were: the exotics Pontoscolex corethrurus (Glossoscolecidae), Dichogaster affinis, D. bolani and D. saliens (Acanthodrilidae), Eukerria saltensis, E. eiseniana and Ocnerodrilus occidentalis (Ocnerodrilidae), and Amynthas sp. (Megascolecidae); the native species Glossoscolex n. sp. and Fimoscolex n. sp. (Glossoscolecidae), Belladrilus n. sp.1 and an unidentifiable Ocnerodrilidae n. sp.1 (probably Belladrilus); and two unidentified Eukerria spp. (of unknown origin) (Ocnerodrilidae). Pasture conversion to row crops had a negative effect on earthworm abundance and diversity: fewer individuals and species were found in the cropping systems than the pastures. The forest was not a suitable reference site, having low earthworm populations and diversity. Exotic species tended to predominate in the land use systems near Jaguapita, but native earthworm species still survived, even in degraded pastures and row crops, many years after deforestation.