@article{298072dbd5bb4e8ebcaf295f6f3b1230,
title = "Biogeographic features mediate marine subsidies to island food webs",
abstract = "Although marine subsidies often enrich terrestrial ecosystems, their influence is known to be context-dependent. Additionally, the multitrophic impact of marine subsidies has not been traced through food webs across physically diverse islands. Here, we test predictions about how island characteristics can affect marine enrichment of food web constituents and how nutrients flow through island food webs. To evaluate enrichment and trace marine nutrients across food webs, we used stable isotopes of soil, flora, and fauna (n = 4752 samples) collected from 97 islands in British Columbia, Canada. Island area was the strongest predictor of enrichment across taxa; we found that samples were more 15N-rich on smaller islands. Enrichment declined with distance from shore but less so on small islands, implying a higher per-unit-area subsidy effect. These area and distance-to-shore effects were taxon-specific, and nearly twice as strong in basal food web groups. We also found that increases in δ15N correlated with increases in %N in basal trophic groups, as well as in songbirds, implying biologically relevant uptake of a potentially limiting nutrient. Path analysis demonstrated that subsidies in soil flow through plants and detritivores, and into upper-level consumers. Our results reveal an interplay between island biogeography and marine subsidies in shaping island food webs through bottom-up processes.",
keywords = "cross-boundary nutrient transfers, food webs, island biogeography, marine-derived nutrients, meta-ecosystem, spatial subsidies, stable isotopes, trophic ecology",
author = "Obrist, {Debora S.} and Hanly, {Patrick J.} and Brown, {Norah E.M.} and Ernst, {Christopher M.} and Wickham, {Sara B.} and Fitzpatrick, {Owen T.} and Kennedy, {Jeremiah C.} and Wiebe Nijland and Reshitnyk, {Luba Y.} and Darimont, {Chris T.} and Starzomski, {Brian M.} and Reynolds, {John D.}",
note = "Funding Information: We are grateful to the Ha{\'i}ɫzaqv and Wuikinuxv First Nations for their support in conducting this research. We also thank all the 100 island field and laboratory technicians for their hard work on this project, the Hakai Institute for field and laboratory support, and Carl Humchitt for his guidance and knowledge. In addition, we would like to thank Jane Pendray for guidance with field season planning, Allison Dennert for sharing plant expertise, and several other members of the Reynolds Lab and the Earth to Ocean Research Group for statistical advice. This work was supported by the Tula Foundation at the Hakai Institute, MITACS, and NSERC Discovery Grants to John D. Reynolds, Brian M. Starzomski, and Chris T. Darimont. Funding Information: We are grateful to the Ha{\'i}ɫzaqv and Wuikinuxv First Nations for their support in conducting this research. We also thank all the 100 island field and laboratory technicians for their hard work on this project, the Hakai Institute for field and laboratory support, and Carl Humchitt for his guidance and knowledge. In addition, we would like to thank Jane Pendray for guidance with field season planning, Allison Dennert for sharing plant expertise, and several other members of the Reynolds Lab and the Earth to Ocean Research Group for statistical advice. This work was supported by the Tula Foundation at the Hakai Institute, MITACS, and NSERC Discovery Grants to John D. Reynolds, Brian M. Starzomski, and Chris T. Darimont. Publisher Copyright: {\textcopyright} 2022 The Authors. Ecosphere published by Wiley Periodicals LLC on behalf of The Ecological Society of America.",
year = "2022",
month = jul,
doi = "10.1002/ecs2.4171",
language = "English",
volume = "13",
journal = "Ecosphere",
issn = "2150-8925",
publisher = "Wiley-Blackwell",
number = "7",
}