Open AccessStable isotope mixing models demonstrate the role of an invasive plant in wetland songbird food webs
Author(s) -
Wigginton Rachel D.,
Van Grootheest Chloe,
Spautz Hildie,
Grenier J. Letitia,
Whitcraft Christine R.
Publication year - 2022
Publication title -
applications in plant sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 23
ISSN - 2168-0450
DOI - 10.1002/aps3.11486
Subject(s) - trophic level , biology , sparrow , ecology , food web , isotope analysis , wetland , omnivore , ecosystem , songbird , abundance (ecology) , predation
Premise Invasive plants in wetlands are often ecosystem engineers, mediating changes in ecosystem functions like trophic support. We documented the impacts of Lepidium latifolium , an invasive plant, on the food web of omnivorous birds (Suisun song sparrows, Melospiza melodia maxillaris ) in a tidal wetland of northern California, USA. Methods We used analysis of natural abundance stable isotopes of 13 C and 15 N in song sparrow blood, invertebrate food sources, L. latifolium seeds, and other marsh plant seeds to inform Bayesian, concentration‐dependent mixing models that predicted average song sparrow diets. Results Season and plant phenology influenced food source incorporation and isotopic signatures. Song sparrows showed higher isotopic variability in the summer. The observed changes in song sparrow diets were driven by altered invertebrate communities related to seasonal L. latifolium presence and by shifts from seeds to consumption of invertebrate food sources during the breeding season in the spring and summer. Discussion This study used stable isotope tools and modeling to demonstrate two mechanisms of isotopic influence by L. latifolium on omnivorous song sparrows. This study can inform site‐ and species‐specific management strategies by demonstrating how changes to the plant community can impact entire trophic systems.