From 1990 through 1992, nematodes were extracted from soil samples tak
en from the rhizosphere of native species of grapes from four areas of
northern California and two areas of southern California. For compari
son, samples from domestic grapes as well as a putative hybrid of Viti
s californica and V. vinifera were also taken. Rhizosoil from Californ
ia native grapevine contained many more species of nematodes than did
soil obtained from cultivated forms of V. vinifera. Taxonomic and trop
hic diversity was much higher in nematodes from sampling sites from na
tive grapes than in those from grapes maintained in vineyard situation
s. Ordination methods using correspondence analysis showed both simila
rities and differences in the faunal assemblages of nematodes from the
different sampling sites, based on indexes of species and trophic gro
ups. Collected data indicate that nematode communities with high troph
ic and taxonomic diversity have a lower numerical density of plant par
asites.