Interpopulation resource partitioning of Lesser Frigatebirds and the influence of environmental context

Rowan Mott, Ashley Herrod, Rohan Clarke

Research output: Contribution to journalArticleResearchpeer-review

5 Citations (Scopus)

Abstract

Conspecific individuals inhabiting nearby breeding colonies are expected to compete strongly for food resources owing to the constraints imposed by shared morphology, physiology, and behavior on foraging strategy. Consequently, colony-specific foraging patterns that effectively partition the available resources may be displayed. This study aimed to determine whether intraspecific resource partitioning occurs in two nearby colonies of Lesser Frigatebirds (Fregata ariel). A combination of stable isotope analysis and GPS tracking was used to assess dietary and spatial partitioning of foraging resources during the 2013 and 2014 breeding seasons. These results were compared to vessel-derived estimates of prey availability, local primary productivity, and estimates of reproductive output to suggest potential drivers and implications of any observed partitioning. Isotopic data indicated a more neritic source of provisioned resources for near-fledged chicks at an inshore colony, whereas their offshore counterparts were provisioned with resources with a more pelagic signal. Deep pelagic waters (>200 m) had higher availability of a preferred prey type despite a trend for lower primary productivity. Differences in foraging ecology between the two populations may have contributed to markedly different reproductive outputs. These findings suggest environmental context influences dietary and spatial aspects of foraging ecology. Furthermore, the effect of colony-specific foraging patterns on population demography warrants further research.

Original languageEnglish
Pages (from-to)8583-8594
Number of pages12
JournalEcology and Evolution
Volume6
Issue number23
DOIs
Publication statusPublished - 1 Dec 2016

Keywords

  • competition
  • demography
  • foraging conditions
  • intraspecific partitioning
  • population ecology
  • prey availability

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