10.5061/DRYAD.6M905QG38
Glassic, Hayley
0000-0001-6839-1026
United States Geological Survey
Guy, Christopher
United States Geological Survey
Lujan, Dominique
University of Wyoming
Tronstad, Lusha
University of Wyoming
Briggs, Michelle
Montana State University
Albertson, Lindsey
Montana State University
Koel, Todd
National Park Service
Invasive predator diet plasticity has implications for native fish
conservation & invasive species suppression
Dryad
dataset
2022
FOS: Agriculture, forestry, and fisheries
National Park Service
https://ror.org/044zqqy65
P16AC00948
2022-12-12T00:00:00Z
2022-12-12T00:00:00Z
en
403025 bytes
6
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Diet plasticity is a common behavior exhibited by piscivores to sustain
predator biomass when preferred prey biomass is reduced. Invasive
piscivore diet plasticity could complicate suppression success; thus,
understanding invasive predator consumption is insightful to meeting
conservation targets. Here, we determine if diet plasticity exists in an
invasive apex piscivore and how plasticity could influence native species
recovery benchmarks and invasive species suppression goals. We compared
diet and stable isotope signatures of invasive lake trout and native
Yellowstone cutthroat trout (cutthroat trout) from Yellowstone Lake,
Wyoming, U.S.A. as a function of no, low-, moderate-, and high-lake trout
density states. Lake trout exhibited plasticity in relation to their
density; consumption of cutthroat trout decreased 5-fold (diet proportion
from 0.89 to 0.18) from low- to high-density state. During the
high-density state, lake trout switched to amphipods, which were also
consumed by cutthroat trout, resulting in high diet overlap (Schoener’s
index value, D = 0.68) between the species. As suppression reduced lake
trout densities, more cutthroat trout (moderate-density state proportion
of cutthroat trout = 0.42) were consumed, and diet overlap was released
between the species (D = 0.30). A shift in lake trout δ13C signatures from
the high- to the moderate-density state also corroborated increased
consumption of cutthroat trout and lake trout diet plasticity. Observed
declines in lake trout are not commensurate with expected cutthroat trout
recovery due to lake trout diet plasticity. The abundance of the native
species in need of conservation may take longer to recover due to the diet
plasticity of the invasive species. The changes observed in diet, diet
overlap, and isotopes associated with predator suppression provide more
insight into conservation and suppression dynamics than using predator and
prey biomass alone. By understanding these dynamics, we can better prepare
conservation programs for potential feedbacks caused by invasive species
suppression.