Intercohort size structure dynamics of fire salamander larvae in ephemeral habitats: a mesocosm experiment

Asaf Sadeh, Antonina Polevikov, Marc Mangel, Leon Blaustein

Research output: Contribution to journalArticlepeer-review

Abstract

The size structure of a larval population facilitates interaction asymmetries that, in turn, influence the dynamics of size-structure. In species that exhibit conspicuous aggressive interactions, the competitive effects of the smaller individuals may be overlooked. We manipulated initial size differences between two larval cohorts and young-cohort density of Salamandra infraimmaculata in mesocosms to determine: (1) whether young individuals function primarily as prey or as competitors of older and larger individuals; (2) the resulting dynamics of size variation; and (3) recruitment to the postmetamorph population. Intercohort size differences generally remained constant over time at low young-cohort densities, but reduced over time at high densities due to retardation of the old-cohort growth rate. This suggests a competitive advantage to the young cohort that outweighs the interference advantage of older cohorts previously documented in this species. The increase in mortality from desiccation due to high young-cohort density was an order of magnitude greater in the old cohort than in the young-cohort, further indicating size-dependent vulnerability to competition. However, the conditions least favorable to most of the old-cohort larvae (large size difference and high young-cohort density) promoted cannibalism. Among cannibals, mortality and time to metamorphosis decreased and sizes at metamorphosis increased substantially. Thus, a balance between the competitive advantage to young cohorts, and the interference and cannibalism advantage to old cohorts shapes larval size-structure dynamics. Larval densities and individual expression of cannibalism can shift this balance in opposite directions and alter relative recruitment rates from different cohorts.

Original languageEnglish
Pages (from-to)425-433
Number of pages9
JournalOecologia
Volume179
Issue number2
DOIs
StatePublished - 22 Oct 2015

Bibliographical note

Funding Information:
Many thanks to Arik Kershenbaum, Lior Blank, Michal Segoli, Orr Spiegel, and Tobin Northfield for their feedback on the manuscript. This study was funded by Israel Science Foundation grant (961-2008) awarded to LB, and by Postdoctoral Award No. FI-457-2011 from BARD, The United States-Israel Binational Agricultural Research and Development Fund, awarded to AS. The study was carried out in accordance with the Israeli Nature and Parks Authority permit 2010/37885, and with the University of Haifa Animal Experimentation Ethics Committee permit 212/11.

Publisher Copyright:
© 2015, Springer-Verlag Berlin Heidelberg.

Keywords

  • Amphibians
  • Exploitative competition
  • Fire salamander
  • Niche shifts
  • Priority effects

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

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