Corrigendum to “Role of wood in pumice-bed streams II: Breakdown and colonisation”: [For. Ecol. Manage. 177 (2003) 261–276

Abstract

We measured: (i) decay rates, respiration and invertebrate colonisation of wood blocks, cones, twigs and needles from Pinus radiata in two spring-fed, pumice-bed streams in the central North Island of New Zealand, and (ii) feeding and growth rates of a detritivorous stonefly on wood at different stages of decay, to investigate interactions among decay state, microbial activity and macroinvertebrate utilisation of small wood and associated organic material. Exponential decay coefficients indicated that, overall, needles broke down 19 times faster than twigs, 61 times faster than blocks, and 239 times faster than cones over 1243 days. Respiration rates were low for blocks and cones, and no temporal pattern was evident across the two sites, whereas rates on twigs were an order of magnitude higher than for cones or wood. Similarly, rates on needles were an order of magnitude higher than for twigs; respiration on both twigs and needles increased at both sites from 28 to 84 days. On average, 2.5% of mass loss from cones was attributable to microbial breakdown, compared to 6.7 and 44.3% for blocks and twigs, respectively, and 43.0% for needles. Densities of invertebrates were markedly higher per unit area of twig than for other substrate types on most dates, and were highly and positively correlated with respiration rates when all woody substrates were considered together. Community composition on inorganic substrates differed from woody substrates. Rates of fine particulate organic matter (FPOM) production by stonefly nymphs were significantly higher on highly decayed wood compared to low or moderately decayed wood. However, wood decay state did not have a significant measurable effect on changes in nymphal growth rates. Our study demonstrates that inputs of pine slash to streams can result in a range of organic matter types with varying levels of microbial activity and persistence. The range of small wood types entering streams following harvesting potentially provides a structurally complex and temporally variable array of habitats that influence invertebrate community composition.