Oecologia

, Volume 178, Issue 1, pp 5–16 | Cite as

Factors affecting individual foraging specialization and temporal diet stability across the range of a large “generalist” apex predator

  • Adam E. Rosenblatt
  • James C. Nifong
  • Michael R. Heithaus
  • Frank J. Mazzotti
  • Michael S. Cherkiss
  • Brian M. Jeffery
  • Ruth M. Elsey
  • Rachel A. Decker
  • Brian R. Silliman
  • Louis J. GuilletteJr.
  • Russell H. Lowers
  • Justin C. Larson
Special Topic: Individual-level niche specialization

Abstract

Individual niche specialization (INS) is increasingly recognized as an important component of ecological and evolutionary dynamics. However, most studies that have investigated INS have focused on the effects of niche width and inter- and intraspecific competition on INS in small-bodied species for short time periods, with less attention paid to INS in large-bodied reptilian predators and the effects of available prey types on INS. We investigated the prevalence, causes, and consequences of INS in foraging behaviors across different populations of American alligators (Alligator mississippiensis), the dominant aquatic apex predator across the southeast US, using stomach contents and stable isotopes. Gut contents revealed that, over the short term, although alligator populations occupied wide ranges of the INS spectrum, general patterns were apparent. Alligator populations inhabiting lakes exhibited lower INS than coastal populations, likely driven by variation in habitat type and available prey types. Stable isotopes revealed that over longer time spans alligators exhibited remarkably consistent use of variable mixtures of carbon pools (e.g., marine and freshwater food webs). We conclude that INS in large-bodied reptilian predator populations is likely affected by variation in available prey types and habitat heterogeneity, and that INS should be incorporated into management strategies to efficiently meet intended goals. Also, ecological models, which typically do not consider behavioral variability, should include INS to increase model realism and applicability.

Keywords

American alligator Alligator mississippiensis Stomach content analysis Stable isotope analysis Food web 

Supplementary material

442_2014_3201_MOESM1_ESM.docx (46 kb)
Supplementary material 1 (DOCX 46 kb)

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Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Adam E. Rosenblatt
    • 1
  • James C. Nifong
    • 2
  • Michael R. Heithaus
    • 1
    • 3
  • Frank J. Mazzotti
    • 4
  • Michael S. Cherkiss
    • 5
  • Brian M. Jeffery
    • 4
  • Ruth M. Elsey
    • 6
  • Rachel A. Decker
    • 1
  • Brian R. Silliman
    • 2
  • Louis J. GuilletteJr.
    • 7
  • Russell H. Lowers
    • 8
  • Justin C. Larson
    • 2
  1. 1.Department of Biologica Sciences, Marine Sciences ProgramFlorida International UniversityNorth MiamiUSA
  2. 2.Department of BiologyUniversity of FloridaGainesvilleUSA
  3. 3.School of Environment, Arts, and SocietyFlorida International UniversityNorth MiamiUSA
  4. 4.Fort Lauderdale Research and Education CenterUniversity of FloridaDavieUSA
  5. 5.U.S. Geological Survey, Southeast Ecological Science CenterDavieUSA
  6. 6.Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife RefugeGrand ChenierUSA
  7. 7.Hollings Marine Laboratory, Department of Obstetrics and GynecologyMedical University of South CarolinaCharlestonUSA
  8. 8.InoMedic Health Applications, Kennedy Space CenterCape CanaveralUSA

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