Do fall additions of salmon carcasses benefit food webs in experimental streams?

• Published in: Hydrobiologia Vol. 675; no. 1; pp. 197 - 209
• Main Authors: Cram, Jeremy M., Kiffney, Peter M., Klett, Ryan, Edmonds, Robert L.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.10.2011; Springer; Springer Nature B.V
• Subjects: Animal and plant ecology; Animal populations; Animal, plant and microbial ecology; Autumn; Biological and medical sciences; Biomedical and Life Sciences; Creeks & streams; Ecology; Ecosystems; Fishes; Floodplains; Food chains; Food chains (Ecology); Food webs; Fresh water ecosystems; Freshwater & Marine Ecology; Freshwater ecology; Fundamental and applied biological sciences. Psychology; General aspects; Life Sciences; Load distribution; Primary Research Paper; Salmon; Salmonidae; Spawning; Streams; Summer; Synecology; Zoology; INE, USA, Pacific Northwest; Salmon carcasses; Experimental streams; Recolonization; Aquatic food web; Salmon-derived nutrients; Salmonidae; Salmon; Experimental study; Water vapor; Carcass; Aquatic environment; Vertebrata; Food web; Experimental steams; Hydrobiology; Pisces; Nutrient; Stream
• DOI: 10.1007/s10750-011-0819-9
• ISSN: 0018-8158

Research showing that salmon carcasses support the productivity and biodiversity of aquatic and riparian ecosystems has been conducted over a variety of spatial and temporal scales. In some studies, carcasses were manipulated in a single pulse or loading rate or manipulations occurred during summer and early fall, rather than simulating the natural dynamic of an extended spawning period, a gradient of loading rates, or testing carcass effects in late fall-early winter when some salmon stocks in the US Pacific Northwest spawn. To address these discrepancies, we manipulated salmon carcass biomass in 16 experimental channels located in the sunlit floodplain of the Cedar River, WA, USA between mid-September and mid-December, 2006. Total carcass loads ranged from 0–4.0 kg/m 2 (0, 0.001, 0.01, 0.1, 0.5, 1.0, 2.0 and 4.0 kg/m 2 , n  = 2 per treatment) and were added to mimic the temporal dynamic of an extended spawning period. We found little evidence that carcasses influenced primary producer biomass or fish growth; however, nutrients and some primary consumer populations increased with loading rate. These effects varied through time, however. We hypothesize that the variable effects of carcasses were a result of ambient abiotic condition, such as light, temperature and disturbance that constrained trophic response. There was some evidence to suggest peak responses for primary producers and consumers occurred at a loading rate of ~1.0–2.0 kg/m 2 , which was similar to other experimental studies conducted during summer.