Oecologia

, Volume 173, Issue 3, pp 767–777

Temporal consistency and individual specialization in resource use by green turtles in successive life stages

  • Hannah B. Vander Zanden
  • Karen A. Bjorndal
  • Alan B. Bolten
Behavioral Ecology - Original Research

DOI: 10.1007/s00442-013-2655-2

Cite this article as:
Vander Zanden, H.B., Bjorndal, K.A. & Bolten, A.B. Oecologia (2013) 173: 767. doi:10.1007/s00442-013-2655-2

Abstract

Not all individuals in a population use the same subset of dietary and habitat resources. Patterns of individual specialization have been documented in an increasing number of organisms, but often without an associated time scale over which niche specialization was observed. We examined the patterns in individual resource use through time and in relation to the population with metrics of temporal consistency and degree of individual specialization. We used stable isotope analysis of carbon and nitrogen in successive subsections of scute tissue from the carapace to compare foraging patterns in three successive life stages of the green turtle (Chelonia mydas). Temporal consistency was measured as the mean within-individual variation in stable isotope values through time, whereas the degree of individual specialization was a ratio of the individual variation to that of the population. The distinction between these two parameters is important, as the metric of temporal consistency quantifies the regularity of individual resource use, and the degree of individual specialization indicates what proportion of the population niche an average individual uses. The scute record retains a chronological history of resource use and was estimated to represent a minimum 0.8 years in juveniles to a maximum of 6.5 years in adults. Both temporal consistency and individual specialization varied significantly among life stages. Adults were highly consistent in resource use through time and formed a generalist population with individual specialists maintaining long-term patterns in resource use. Oceanic and neritic juvenile life stages exhibited less temporal consistency in resource use with less individual specialization than adults. These observations are important when considering the ecological roles filled by green turtles in each life stage; also, individual differences in resource use may result in differential fitness consequences.

Keywords

Isotopic niche Foraging patterns Chelonia mydas Ontogeny Scute 

Supplementary material

442_2013_2655_MOESM1_ESM.docx (592 kb)
Supplementary material (DOCX 591 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Hannah B. Vander Zanden
    • 1
  • Karen A. Bjorndal
    • 1
  • Alan B. Bolten
    • 1
  1. 1.Archie Carr Center for Sea Turtle Research and Department of BiologyUniversity of FloridaGainesvilleUSA

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