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Using drilled-undrilled shell damage analysis to estimate crushing predation frequencies in modern marine gastropod assemblages

  • Author / Creator
    Stafford, Emily S.
  • Predation is a frequently studied subject, but estimating crushing predation in mollusk communities is challenging. Shells record successful attacks, but it is not always possible to identify attacks on an individual basis. Repair scar frequency is a common proxy for crushing mortality, but shell repair does not directly measure mortality, so results are ambiguous. Borrowing a technique from Vermeij (1982), crushing mortality frequencies were estimated in a recent shell assemblage. Because crushing damage can be confused with taphonomy, a taphonomic baseline was established: the cause of death of drilled shells is known, so additional damage is postmortem. The frequencies of several damage types were tallied for drilled shells to estimate a taphonomic baseline for the assemblage. The same frequencies were calculated for undrilled shells (cause of death unknown). In many cases, undrilled shells had significantly higher frequencies than drilled shells. The differences in damage frequencies likely are caused by crushing predation.

  • Subjects / Keywords
  • Graduation date
    2010-06
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/R3VB1F
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
    English
  • Institution
    University of Alberta
  • Degree level
    Master's
  • Department
    • Department of Earth and Atmospheric Sciences
  • Supervisor / co-supervisor and their department(s)
    • Leighton, Lindsey R. (Earth and Atmospheric Sciences)
  • Examining committee members and their departments
    • Palmer, A. Richard (Biological Sciences)
    • Gingras, Murray K. (Earth and Atmospheric Sciences)