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Breakdown and Invertebrate Colonization of Leaf Litter in Two Contrasting Streams: Significance of Oligochaetes in a large River

Chauvet, Eric and Giani, Narcisse and Gessner, Mark O. Breakdown and Invertebrate Colonization of Leaf Litter in Two Contrasting Streams: Significance of Oligochaetes in a large River. (1993) Canadian Journal of Fisheries and Aquatic Sciences (CJFAS), 50 (3). 488-495. ISSN 1205-7533

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Official URL: http://dx.doi.org/10.1139/f93-057


The breakdown of willow (Salix alba) and beech (Fagus silvatica) leaves and their colonization by invertebrates were studied in a third-order mountain stream (breakdown rate k = 0.0147 and 0.0052· d-1, respectively) and a seventh-order lowland river (k = 0.0094 and 0.0027·d-1). Willow leaves broke down three times faster than beech leaves; this difference was twice that between streams. Total invertebrate densities and biomass and the proportion of shredders were higher in the large river; therefore, differences in breakdown capacities between streams cannot be attributed to differences in invertebrate community structure. Instead, microbial processing and abiotic fragmentation are suggested as factors controlling breakdown rates. Owing to the abundance of naidids, up to 2000 invertebrates per leaf bag were recorded in the large river. These oligochaetes appeared to use litter accumulations as a microhabitat that provided shelter and a rich supply of food in the form of fine particulate organic matter. Tubificid oligochaetes accounted for 55% of total biomass on partly degraded leaves at this site. Their abundance and regular occurrence inside willow leaves suggest that tubificids enhance leaf fragmentation and possibly mediate the incorporation of organic matter in river sediments once the plant tissue is sufficiently macerated.

Item Type:Article
Additional Information:Thanks to NRC Research Press editor. The definitive version is available at http://www.nrcresearchpress.com/doi/abs/10.1139/f93-057?journalCode=cjfas#.UvH-cvtavxU
Audience (journal):International peer-reviewed journal
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Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
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Deposited On:05 Feb 2014 09:36

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