THE DEGRADATION OF PINE NEEDLES IN A MEDITERRANEAN STREAM

The aim of this study was to investigate the decay of Pinus pinaster n eedles in a Mediterranean stream and the role of macroinvertebrates in this process. Fine and coarse mesh bags containing pine needles or pl astic strips were exposed in the stream and retrieved periodically to determine weight loss of the needles and the numbers and biomass of th e macroinvertebrates associated with these substrates. Degradation rat es of needles were low when compared with other leaf types but in the range of values reported for related species (k = -0.0039 to -0026/day ). Higher rates were obtained in coarse mesh bags than in fine mesh ba gs. Colonization of pine needles was delayed when compared to plastic strips.