Individual specialists within a generalist niche: variable diet of stoats and implications for conservation

McAulay, Jamie; Monks, Joanne M.; Wilson, Deborah; Seddon, Philip J.

doi:10.20417/nzjecol.45.29

Cited by 3 publications

(3 citation statements)

References 64 publications

(90 reference statements)

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“…Additional wolverine diet studies in the RMA are thus necessary to assess if the current generalist population is composed of a few individuals that specialize on reindeer, i.e. specific individuals taking a disproportionate reindeer toll, or if the majority of wolverines are generalists (Mcaulay et al, 2021).…”

Section: Implications For Wolverine Conservationmentioning

confidence: 99%

Long-term dietary shifts in a generalist predator, the wolverine (Gulo gulo)

Massé,

Hiltunen,

Lansink

et al. 2023

Front. Ecol. Evol.

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Over the last hundred years, many large carnivore species have suffered range contractions, population losses, and habitat alterations that may be influencing their dietary preferences. To identify shifting isotopic niches and reconstruct past and present diets from species of high conservation concern, stable isotope analysis (SIA) of δ13C and δ15N values of tissue from museum collections and ongoing non-invasive monitoring programs offers an effective approach. Here, we assessed the long-term alterations in the trophic structure of a generalist large carnivore over a time of population loss and recovery. Wolverine stable carbon (δ13C) and nitrogen (δ15N) isotopes were measured in hair samples collected from 44 individuals in Finland for the period 1905–2020, and potential dietary were quantified using isotopic niche metrics shifts in two study areas. We provide evidence of a long-term diet shift in Finnish wolverines, with a temporal depletion of hair’s δ13C (β = −0.016‰, R² = 0.46, p < 0.001). Correspondingly, there was a shift in the isotopic niches of the Historical population (before the year 2000) and Recent population (after 2000), with the niche overlap between the Historical and Recent periods being only 33% throughout Finland, and even lower in the two study areas (22% to 24%). The breadth of the isotopic niche, however, did not significantly differ between the two periods, suggesting that despite a change in diet composition, wolverines did not specialize more. The trophic level of wolverines in Finland was stable throughout the study period, with no significant change in δ15N with time (β = 0.0055‰, R² = 0.043, p = 0.17). In summary: A) the strong trophic resilience of this top predator was shown by the stability of its niche breadth and trophic level feeding regime during periods of population decline and recovery as well as during a period of major anthropogenic alterations in their environment; B) the use of SIA methods on historical and recent hairs provided a unique tool to unravel long-term changes in wolverine feeding strategies.

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Section: Implications For Wolverine Conservationmentioning

confidence: 99%

Long-term dietary shifts in a generalist predator, the wolverine (Gulo gulo)

Massé,

Hiltunen,

Lansink

et al. 2023

Front. Ecol. Evol.

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“…Additionally, while research in California has documented declines in the native hairy shore crab (Hemigrapsus oregonensis) attributable to green crab [20,21], and the two species frequently co-occur in green crab traps in Washington State [24][25][26], no baseline data exist to robustly evaluate local green crab impacts to H. oregonensis populations. Since feeding behavior of generalist invasive predators can vary substantially across their global range [27,28], local, habitat-specific diet analyses are needed to assess the context-dependence of green crab diets and consequent community impacts.…”

Section: Introductionmentioning

confidence: 99%

Invasive European green crab (Carcinus maenas) predation in a Washington State estuary revealed with DNA metabarcoding

Fisher,

Grason,

Stote

et al. 2024

PLoS ONE

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Predation by invasive species can threaten local ecosystems and economies. The European green crab (Carcinus maenas), one of the most widespread marine invasive species, is an effective predator associated with clam and crab population declines outside of its native range. In the U.S. Pacific Northwest, green crab has recently increased in abundance and expanded its distribution, generating concern for estuarine ecosystems and associated aquaculture production. However, regionally-specific information on the trophic impacts of invasive green crab is very limited. We compared the stomach contents of green crabs collected on clam aquaculture beds versus intertidal sloughs in Willapa Bay, Washington, to provide the first in-depth description of European green crab diet at a particularly crucial time for regional management. We first identified putative prey items using DNA metabarcoding of stomach content samples. We compared diet composition across sites using prey presence/absence and an index of species-specific relative abundance. For eight prey species, we also calibrated metabarcoding data to quantitatively compare DNA abundance between prey taxa, and to describe an ‘average’ green crab diet at an intertidal slough versus a clam aquaculture bed. From the stomach contents of 61 green crabs, we identified 54 unique taxa belonging to nine phyla. The stomach contents of crabs collected from clam aquaculture beds were significantly different from the stomach contents of crabs collected at intertidal sloughs. Across all sites, arthropods were the most frequently detected prey, with the native hairy shore crab (Hemigrapsus oregonensis) the single most common prey item. Of the eight species calibrated with a quantitative model, two ecologically-important native species–the sand shrimp (Crangon franciscorum) and the Pacific staghorn sculpin (Leptocottus armatus)–had the highest average DNA abundance when detected in a stomach content sample. In addition to providing timely information on green crab diet, our research demonstrates the novel application of a recently developed model for more quantitative DNA metabarcoding. This represents another step in the ongoing evolution of DNA-based diet analysis towards producing the quantitative data necessary for modeling invasive species impacts.

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“…Additionally, while previous research has documented declines in the native hairy shore crab ( Hemigrapsus oregonensis ) attributable to green crab in California (Grosholz et al, 2000; de Rivera et al, 2011), and the two species overlap extensively in Washington (WSG Crab Team), no baseline data exist to robustly evaluate local green crab impacts to H. oregonensis populations. Yet, feeding behavior of generalist invasive predators can vary substantially across their global range (Glassic et al, 2023; McAulay et al, 2021). Thus, local, habitat-specific diet analyses are needed to assess the variability and context dependence of diets and consequent community impacts.…”

Section: Introductionmentioning

confidence: 99%

Invasive European green crab (Carcinus maenas) predation revealed with quantitative DNA metabarcoding

Fisher,

Grason,

Stote

et al. 2023

Preprint

View full text Add to dashboard Cite

Predation by invasive species can threaten local ecosystems and economies. The European green crab (Carcinus maenas), one of the most widespread marine invasive species, is an effective predator associated with clam and crab population declines outside of its native range. In the U.S. Pacific Northwest, green crab have recently experienced increases in abundance and expanding distributions, generating concern for estuarine ecosystems and associated aquaculture production. However, regionally-specific information on the trophic impacts of invasive green crab is highly limited. We compared the stomach contents of green crabs collected on aquaculture beds versus natural intertidal sloughs in Willapa Bay, Washington, to provide the first in-depth description of European green crab diet at a particularly crucial time for regional management. We first identified putative prey items using DNA metabarcoding. For key prey species, we also applied a quantitative model to calculate the true abundance of each species in stomach content DNA samples. From the stomach contents of 62 green crabs, we identified 56 unique taxa belonging to nine phyla. The stomach contents of crabs collected from aquaculture beds were significantly different from the stomach contents of crabs collected at natural intertidal sloughs. Across all sites, arthropods were the most frequently detected prey, with the native hairy shore crab (Hemigrapsus oregonensis) the single most common prey item. Of the eight species included in the quantitative model, two ecologically-important native species – the sand shrimp (Crangon franciscorum)and the Pacific staghorn sculpin (Leptocottus armatus) – were the most abundant in crab stomach contents, when present. In addition to providing timely information on green crab diet, our research demonstrates the novel application of a recently developed model for quantitative DNA metabarcoding. This represents another step in the ongoing evolution of DNA-based diet analysis towards producing the quantitative data necessary for modeling invasive species impacts.

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Individual specialists within a generalist niche: variable diet of stoats and implications for conservation

Cited by 3 publications

References 64 publications

Long-term dietary shifts in a generalist predator, the wolverine (Gulo gulo)

Long-term dietary shifts in a generalist predator, the wolverine (Gulo gulo)

Invasive European green crab (Carcinus maenas) predation in a Washington State estuary revealed with DNA metabarcoding

Invasive European green crab (Carcinus maenas) predation revealed with quantitative DNA metabarcoding

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