SOIL NEMATODES AS INDICATORS OF THE EFFECT OF MANAGEMENT ON GRASSLANDS IN THE NEW-ENGLAND TABLELANDS (NSW) - COMPARISON OF NATIVE AND IMPROVED GRASSLANDS

Winter samples from 0-30 cm soil depth in ungrazed native and improved grasslands gave soil nematode population estimates of 2,637,000 and 1 0,418,000 m(-2) respectively. Some 60 nematode taxa were distinguished , and there were marked changes in the taxonomic composition of the fa una. The absence of cultivation and mammalian grazing reduced possibil ities for invasion by new nematode taxa. While loss of plant-feeding s pecies and marked increase in microbial-feeding species significantly decreased species richness (SR = 4.27-3.03 and 3.30-2.48 in 0-10 and 1 0-20 cm soil, respectively), there were no significant changes in dive rsity (H') of the nematode fauna following pasture improvement. Change s in the composition of the nematode fauna were reflected in declines in the maturity index (Sigma MI); this supports a close relationship b etween nematode activity and nutrient cycling.