2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/21/2018 | 11:30 AM - 11:45 AM | WINTER BASEFLOW CRITIAL FOR STREAM FOOD WEB PRODUCTIVITY IN APLINE STREAMS | 420 A
WINTER BASEFLOW CRITIAL FOR STREAM FOOD WEB PRODUCTIVITY IN APLINE STREAMS
Stream basal resource availability, both autochthonous (i.e., within-system; e.g., biofilm) and allochthonous (i.e., external; e.g., coarse benthic organic matter [CBOM]), depends on catchment and stream characteristics (e.g., terrestrial vegetation, hydrological regime) and likely determines food web structure and function. We studied biofilm, CBOM, and macroinvertebrates in three catchments with differing degrees of glacial runoff, and thus hydrological regime, and vegetation cover (alpine prairie to subalpine forest). Biofilm chlorophyll-a (chla) was highest in winter months (Dec-Apr; monthly mean 0.54-1.38 mg/m2) with a secondary peak in September for snowmelt-dominated streams (1.87 mg/m2) while other streams and months had generally low chla (mean <0.32 mg/m2). CBOM was higher in the snowmelt-dominated streams compared to the glacial-fed streams (mean 8.6 vs 4.0 g/m2) without seasonal patterns. Macroinvertebrates consisted mainly of Diptera, Plecoptera and Ephemeroptera with compositions shifting with season and dependent on stream. For example, Baetidae were abundant Mai-July in all streams while high densities of very small Plecoptera coincided with the high chla found in September in snowmelt-dominated streams. Results suggest that hydrological regime drives patterns in food webs with the winter baseflow representing a critical period of high productivity in Alpine streams.
- Biofilm
- Allochthonous
- Temporal
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Presenters/Authors
Janine Rüegg
(), University of Lausanne, janine.ruegg@unil.ch;
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Tom Battin
(), Ecole Polytechnique Fédérale de Lausanne, tom.battin@epfl.ch;
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