Contribution
Carcass deposition to suppress invasive lake trout causes differential mortality of two common benthic invertebrates in Yellowstone Lake
Briggs, Michelle A.; Albertson, Lindsey K.; Lujan, Dominique R.; Tronstad, Lusha M.; Glassic, Hayley C.; Guy, Christopher S.; Koel, Todd M.
Fundamental and Applied Limnology Volume 194 Nr. 4 (2021), p. 285 - 295
50 références bibliographiques
publié: Feb 25, 2021
publication en ligne: Nov 18, 2020
manuscrit accepté: Oct 29, 2020
révision final du manuscrit reçu: Oct 29, 2020
révision du manuscrit demandée: Oct 13, 2020
manuscrit reçu: Jul 13, 2020
ArtNo. ESP141019404000, Prix: 29.00 €
Abstract
Invasive species require management to mitigate their harmful effects on native biodiversity and ecosystem processes. However, such management can also have negative, unintended consequences on non-target taxa, ecosystem processes, and food web dynamics. In Yellowstone Lake, invasive lake trout (Salvelinus namaycush) have caused a decline in the native Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) population. To suppress the invader, lake trout carcasses are deposited on the species’ spawning sites, causing embryo mortality by reducing dissolved oxygen as they decay. The non-target effects of carcass deposition are unknown, but benthic invertebrates may be sensitive to reductions in dissolved oxygen. Benthic invertebrate taxa have varying hypoxia tolerances; caddisflies of the family Limnephilidae are hypoxia sensitive whereas the amphipods Gammarus lacustris and Hyalella azteca are hypoxia tolerant. Both taxa are widespread and abundant in Yellowstone Lake and comprise a large proportion of fish diets, and changes in their abundances could therefore alter food web dynamics. We conducted an in situ experiment to determine if carcass deposition causes mortality in these two benthic invertebrate taxa. The probability of mortality for caddisflies was 3.15 times higher in carcass treatments compared to controls, while amphipod mortality did not change in response to carcass treatment. Amphipods, which contribute most significantly to fish diets, are unlikely to be reduced in response to carcass deposition, which is confined to a small fraction of the lake where lake trout spawn, limiting the possibility for lake-wide effects. We conclude that carcass deposition is unlikely to alter the availability of invertebrates as a food source for fish in Yellowstone Lake.
Mots-clefs
Amphipoda • anoxic • caddisfly • fish carcass • hypoxic • invasive species management • non-target taxa • Trichoptera