Leaf breakdown along an altitudinal stream gradient
Fabre, Eric; Chauvet, Eric
Archiv für Hydrobiologie Volume 141 Number 2 (1998), p. 167 - 179
published: Feb 19, 1998
ArtNo. ESP141014102008, Price: 29.00 €
Breakdown of alder (Alnus glutinosa) leaf litter was followed in fourteen sampling stations along a 1400 m altitudinal gradient of a 1st to 3rd-order undisturbed stream. Altitudinal patterns of leaf mass loss, nitrogen concentration in the leaves, fungal biomass determined as ergosterol content, and numbers and biomass of shredders and total macroinvertebrates associated with the decomposing leaf litter were analysed using rank and linear correlations. The breakdown rate (0.020-0.041 d-1) almost doubled from the upper to the lower sites and exhibited a significant correlation with altitude. The abundance of shredders, which largely dominated invertebrate assemblages on leaf litter, was negatively correlated both with altitude and percentage of leaf mass remaining after 13 days. Similarly, fungal biomass on leaf litter showed a negative linear correlation with altitude after 37 days. These results, which contrast with those of other studies, suggest that the increasing role of shredders and microfungi as one goes downstream can explain the altitudinal pattern of leaf litter breakdown in streams.