Effect of Pinus radiata logging on stream invertebrate communities in Hawke's Bay, New Zealand

Abstract

Invertebrate communities and associated environmental characteristics were monitored at three Pinus radiata and three pasture stream sites in the Pakuratahi and Tamingimingi Stream catchments, New Zealand, respectively, at nine irregular intervals between December 1996 and April 2001. The Pakuratahi sites were logged between May 1998 and September 1999. Following logging the Pakuratahi Stream invertebrate communities changed from being dominated by a diversity of mayfly species to communities dominated by a high abundance of Chironomidae, Aoteapsyche sp., Elmidae, Ostra‐coda, and Potamopygrus antipodarum. Invertebrate communities that developed following the pine forest harvesting closely resembled those at pasture stream sites in the adjoining Tamingimingi catchment. Invertebrate communities at the pasture stream sites were dominated throughout the study by the same taxa as in the post‐harvest pine sites, except immediately following a storm in July 1997 when mayflies became proportionally more abundant. Biotic indices of water quality, such as the Macroinvertebrate Community Index and Quantitative Macroinvertebrate Community Index, reflected the change in invertebrate communities at the Pakuratahi sites after harvesting, shifting from impact “sensitive” taxa to more “tolerant” taxa. In April 2001 (1.5–2.5 years after harvesting) invertebrate communities had not recovered to their pre‐harvest structure. Recovery of invertebrate communities from a natural disturbance, a major storm in July 1997, was much more rapid (5 months) than the recovery observed from forest harvesting, however. An increase in streambed fine sediment may have been primarily responsible for the changes to invertebrate communities following forest harvesting.