The long term effect of forest logging on the macroinvertebrates in a Fijian stream

The species richness and abundance of macroinvertebrates were assessed in t wo adjacent similar streams, the Nabukavesi and Wainikovu creeks (Viti Levu , Fiji) at intervals of 2 months for 3 years. Previous logging of rain fore st in the Nabukavesi catchment had subjected it to suspended sediment loads and to sediment and grit deposition on its substrate, In contrast the fore st in the Wainikovu catchment had not been logged. Species richness was sig nificantly higher (11-18 species; total 38 spp.) in the unlogged Wainikovu Creek than in the Nabukavesi Creek (eight to 15 species; total 34 spp.) ove r the 3-year period. Diversity indices confirmed greater species diversity in the Wainikovu creek. The total abundance of invertebrates varied conside rably within streams, but not significantly between them over 3 years. The most abundant species in both streams were the caddis fly, Abacaria fijiana , mayflies, Cloeon spp. and Pseudocloeon sp. and atyid shrimps, Caridina sp p.