The population dynamics of nematode communities were studied during a rice
cropping season in 22 fields in the humid forest zone of Cote d'Ivoire. Rai
nfed upland, hydromorphic, and lowland rice fields were examined during the
1996 growing season and compared to nematode communities in adjacent undis
turbed forest and vegetation. Forest clearance and burning had little immed
iate influence on nematode species diversity. Thirty days after the introdu
ction of rice, nematode species diversity across ecosystems was reduced by
57% to seventeen species. At harvest, species diversity was 55% lower than
in adjacent forest and vegetation. With progression of the season, a small
percentage of nematode genera became numerically dominant, while the greate
r proportion of nematode genera were present at low mean intensity. At harv
est Meloidogyne spp. were numerically dominant in upland rice and Hemicycli
ophora oostenbrinki numerically dominant in hydromorphic rice, accounting f
or 74 and 75% of total mean intensity in upland and hydromorphic ecosystems
, respectively. Lowland rice communities were characterised by low nematode
intensity and low species diversity. Dominant species at harvest were Heli
cotylenchus spp. (52% of total mean intensity) which were undetected at sow
ing. Other nematodes which persisted under rice at low mean intensity in va
rious ecosystems were Trichodorus eburneus, Xiphinema hygrophilum and Praty
lenchus brachyurus.