Macroinvertebrate response to salmon carcass analogue treatments: exploring the relative influence of nutrient enrichment, stream foodweb, and environmental variables

Nutrient Enrichment with Salmon Carcass Analogs in the Columbia River Basin, USA: A Stream Food Web Analysis

“…In southeast Alaska, Wipfli et al (2004) found that SCA enhanced the growth of juvenile salmonids in mesocosms and in a natural stream comparable to salmon carcass inputs. In central Idaho streams of the upper Salmon River, Kohler et al (2008) reported that periphyton chlorophyll a, ash-free dry mass, and macroinvertebrate biomass were significantly higher in stream reaches treated with SCA, and Kohler and Taki (2010) observed spatial ordination shifts in macroinvertebrate communities associated with increased relative abundances following SCA treatments in the same streams. These studies represent evaluations at different trophic levels and across diverse landscapes, providing preliminary evaluations of the efficacy of SCA as a management tool.…”

“…In addition, simply measuring changes in density may obscure potential risks associated with nutrient enrichment, such as those described by Davis et al (2010) where long-term dissolved, inorganic nutrient enrichment decoupled predator and prey production within macroinvertebrate communities in southern Appalachian streams. Alternatively, an evaluation of macroinvertebrate community composition and structure before and after SCA additions by Kohler and Taki (2010) did not reveal obvious negative responses, although this study was limited, used a different form of nutrient treatment (i.e., SCA), and did not represent a long-term data set. Long-term and large-scale studies evaluating the significance of these differences relative to the goals and objectives of alternative nutrient enrichment strategies like SCA will help inform scientists and natural resource managers.…”

“…Research investigating the potential utility of SCA has been limited to short-term responses by using experimental stream channels ) and small-scale natural stream experiments, usually focusing on lower trophic levels (Kohler et al 2008;Kohler and Taki 2010; but see Wipfli et al 2004). In southeast Alaska, Wipfli et al (2004) found that SCA enhanced the growth of juvenile salmonids in mesocosms and in a natural stream comparable to salmon carcass inputs.…”

Effects of nutrient replacement on benthic macroinvertebrates in an ultraoligotrophic reach of the Kootenai River, 2003–2010

“…Macroinvertebrates simultaneously support higher trophic level production and consume lowertrophic level organisms (Huryn and Wallace 2000). The intermediate positions of this group of organisms in freshwater food webs has enabled researchers and managers to characterize lotic ecosystems and evaluate responses to largescale alteration, habitat restoration, and nutrient enhancement by monitoring benthic macroinvertebrates (Quamme and Slaney 2003, Allan and Castillo 2007, Kohler and Taki 2010, Kohler et al 2012, Bellmore et al 2013, Cross et al 2013.…”

Water quality, chlorophyll, and periphyton responses to nutrient addition in the Kootenai River, Idaho

“…N and P additions in aquatic systems can increase periphyton biomass, chlorophyll accrual rate, and the abundance and biomass of plankton and invertebrate communities (Kohler et al 2008, Kohler andTaki 2010). Investigators also have reported significant increases in salmon production following nutrient addition in nutrient-depleted lakes and streams in British Columbia, Idaho, and Alaska (Johnson et al 1990, Stockner 2003.…”