Dietary Niche Variation in an Invasive Omnivore: The Effects of Habitat on Feral Pig Resource Use in Hawai‘i

ABSTRACT Invasive omnivores may have profound impacts on ecological communities through diet selection, particularly when their functional roles differ from those in their native range. While the threat of feral pigs (Sus scrofa) to native plant communities in Hawai‘i is well known, their trophic dy...

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Main Authors: Michael S. Peyton, Kealohanuiopuna M. Kinney, Sarah Knox, Grace Tredennick, Sara Hotchkiss
Format: Article
Language:English
Published: Wiley 2024-10-01
Series:Ecology and Evolution
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Online Access:https://doi.org/10.1002/ece3.70417
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author Michael S. Peyton
Kealohanuiopuna M. Kinney
Sarah Knox
Grace Tredennick
Sara Hotchkiss
author_facet Michael S. Peyton
Kealohanuiopuna M. Kinney
Sarah Knox
Grace Tredennick
Sara Hotchkiss
author_sort Michael S. Peyton
collection DOAJ
description ABSTRACT Invasive omnivores may have profound impacts on ecological communities through diet selection, particularly when their functional roles differ from those in their native range. While the threat of feral pigs (Sus scrofa) to native plant communities in Hawai‘i is well known, their trophic dynamics and the drivers of variation in their diet remain understudied. We investigated the feral pig trophic niche on Hawai‘i Island using stable isotopes (13C and 15N) and Bayesian mixing models to identify drivers of variation in resource use. We also reconstructed intra‐individual variability for six subsampled individuals to understand temporal variation in resource use and individual diet specialization. Our results revealed that feral pigs on Hawai‘i Island exhibit a broad trophic niche characterized by diverse diets, with substantial overlap in resource use across districts and habitats. Differences in dietary composition in the transition from forest to open habitat were driven primarily by a decline in invertebrates and an increasing reliance on resources enriched in 15N, which may reflect a shift in protein sources with habitat. Pigs in forested areas exhibited a smaller trophic niche than those in open habitats, largely driven by differences in feeding strategies and resource availability. Diets for subsampled individuals varied little, suggesting feral pig resource‐use strategies in Hawai‘i tend to be relatively stable through time. Individual niche width was relatively narrow compared to that of feral pigs in Hawai‘i at large, indicating the relatively wide feral pig dietary niche is characterized by substantial intraspecific diet specialization, likely as a result of strong intraspecific competition. Understanding the drivers of feral pig resource use offers key information for management strategies aimed at mitigating their ecological impacts in imperiled systems like Hawai‘i.
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spelling doaj-art-cf65cb88ca774c69a09a35abe4921ae32025-08-20T02:32:14ZengWileyEcology and Evolution2045-77582024-10-011410n/an/a10.1002/ece3.70417Dietary Niche Variation in an Invasive Omnivore: The Effects of Habitat on Feral Pig Resource Use in Hawai‘iMichael S. Peyton0Kealohanuiopuna M. Kinney1Sarah Knox2Grace Tredennick3Sara Hotchkiss4University of Wisconsin‐Madison, Botany Madison Wisconsin USAInstitute for Pacific Islands Forestry United States Forest Service Hilo Hawaii USAInstitute for Pacific Islands Forestry United States Forest Service Hilo Hawaii USAInstitute for Pacific Islands Forestry United States Forest Service Hilo Hawaii USAUniversity of Wisconsin‐Madison, Botany Madison Wisconsin USAABSTRACT Invasive omnivores may have profound impacts on ecological communities through diet selection, particularly when their functional roles differ from those in their native range. While the threat of feral pigs (Sus scrofa) to native plant communities in Hawai‘i is well known, their trophic dynamics and the drivers of variation in their diet remain understudied. We investigated the feral pig trophic niche on Hawai‘i Island using stable isotopes (13C and 15N) and Bayesian mixing models to identify drivers of variation in resource use. We also reconstructed intra‐individual variability for six subsampled individuals to understand temporal variation in resource use and individual diet specialization. Our results revealed that feral pigs on Hawai‘i Island exhibit a broad trophic niche characterized by diverse diets, with substantial overlap in resource use across districts and habitats. Differences in dietary composition in the transition from forest to open habitat were driven primarily by a decline in invertebrates and an increasing reliance on resources enriched in 15N, which may reflect a shift in protein sources with habitat. Pigs in forested areas exhibited a smaller trophic niche than those in open habitats, largely driven by differences in feeding strategies and resource availability. Diets for subsampled individuals varied little, suggesting feral pig resource‐use strategies in Hawai‘i tend to be relatively stable through time. Individual niche width was relatively narrow compared to that of feral pigs in Hawai‘i at large, indicating the relatively wide feral pig dietary niche is characterized by substantial intraspecific diet specialization, likely as a result of strong intraspecific competition. Understanding the drivers of feral pig resource use offers key information for management strategies aimed at mitigating their ecological impacts in imperiled systems like Hawai‘i.https://doi.org/10.1002/ece3.70417dietdietary nicheferal pigHawaiiomnivorespecialization
spellingShingle Michael S. Peyton
Kealohanuiopuna M. Kinney
Sarah Knox
Grace Tredennick
Sara Hotchkiss
Dietary Niche Variation in an Invasive Omnivore: The Effects of Habitat on Feral Pig Resource Use in Hawai‘i
Ecology and Evolution
diet
dietary niche
feral pig
Hawaii
omnivore
specialization
title Dietary Niche Variation in an Invasive Omnivore: The Effects of Habitat on Feral Pig Resource Use in Hawai‘i
title_full Dietary Niche Variation in an Invasive Omnivore: The Effects of Habitat on Feral Pig Resource Use in Hawai‘i
title_fullStr Dietary Niche Variation in an Invasive Omnivore: The Effects of Habitat on Feral Pig Resource Use in Hawai‘i
title_full_unstemmed Dietary Niche Variation in an Invasive Omnivore: The Effects of Habitat on Feral Pig Resource Use in Hawai‘i
title_short Dietary Niche Variation in an Invasive Omnivore: The Effects of Habitat on Feral Pig Resource Use in Hawai‘i
title_sort dietary niche variation in an invasive omnivore the effects of habitat on feral pig resource use in hawai i
topic diet
dietary niche
feral pig
Hawaii
omnivore
specialization
url https://doi.org/10.1002/ece3.70417
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