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  • 2000-2004  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    Oxford UK : Blackwell Science Ltd
    Freshwater biology 46 (2001), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. Traps for litterfall and for lateral transport of organic matter were sampled over a 1-year period along longitudinal and lateral transects in a glacial stream system (Val Roseg, Swiss Alps), which is characterized by single-thread reaches and a large subalpine floodplain.2. Allochthonous inputs to the glacier stream were low close to the glacier terminus but increased as woody riparian vegetation and forests develop. Annual inputs varied from 0.4 g ash free dry matter (AFDM) m–2 year–1 (direct input) and 0.7 g AFDM m–2 year–1 (lateral input) in the proglacial area to 23.0 g AFDM m–2 year–1 (direct input) and 10.7 g AFDM m–2 year–1 (lateral input) in the lowest reach with adjacent subalpine forests.3. Direct inputs of organic matter decreased exponentially from forests at the floodplain edge to the floodplain centre, while lateral inputs of organic matter correlated linearly with distance to trees. Direct litterfall dominated litter input close to the forest, while lateral transport was the major pathway for channels more than 20 m away from the forest.4. A conceptual framework is developed illustrating the influence of terrestrial vegetation and fluvial morphology on organic matter input along the continuum of glacial streams.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford UK : Blackwell Science Ltd
    Freshwater biology 46 (2001), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. Food sources and trophic structure of the macroinvertebrate community along a longitudinal gradient were examined in a glacier stream of the Swiss Alps (Val Roseg). Analysis of multiple stable isotopes (δ13C and δ15N) and measurement of C : N ratios were used to differentiate between allochthonous and autochthonous organic matter.2. Although isotopic signatures of algae varied widely among sites and dates, it was possible to discriminate between allochthonous and autochthonous food sources using a site-specific approach.3. Dominant food sources of herbivorous invertebrates in all main channel sites were epilithic diatoms and the filamentous gold alga Hydrurus foetidus. Allochthonous organic matter was of some importance only in a groundwater-fed stream close to the floodplain margin.4. Seasonal changes in the δ13C signature of the macroinvertebrates corresponded with seasonal changes in δ13C of the gold alga H. foetidus. This indicated that the energy base remains autochthonous throughout the year.5. Because of limited food sources, feeding plasticity of the invertebrate community was high. Both grazers and shredders fed predominantly on algae, whereas gatherer-collectors seemed to be omnivorous.6. The overall enrichment of δ15N was 2.25‰ (r2=0.99) per trophic level. On a gradient from the glacier site to a downstream forested site trophic enrichment was constant but variation in δ15N within trophic levels decreased.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
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