Biodiversity and Conservation

, Volume 18, Issue 12, pp 3325–3336

Coral mortality versus structural collapse as drivers of corallivorous butterflyfish decline

  • N. A. J. Graham
  • S. K. Wilson
  • M. S. Pratchett
  • N. V. C. Polunin
  • M. D. Spalding
Brief communication

DOI: 10.1007/s10531-009-9633-3

Cite this article as:
Graham, N.A.J., Wilson, S.K., Pratchett, M.S. et al. Biodivers Conserv (2009) 18: 3325. doi:10.1007/s10531-009-9633-3

Abstract

As climate change increasingly threatens biodiversity, identifying specific drivers of species loss as well as the attributes of species most vulnerable to climatic disturbances is a key challenge to ecologists and conservationists. Here we assess the effects of coral loss versus declines in structural complexity on obligate and facultative coral feeding butterflyfishes on coral reefs in the central and western Indian Ocean. In the inner Seychelles, the abundance of the obligate coral feeding group declined markedly in response to live coral mortality (r2 = 0.48), but showed no further decline with respect to erosion of the physical matrix of the reef. Conversely, the facultative feeding group showed no decline in response to live coral loss, reflecting their feeding versatility; however they did decline in response to structural erosion of the reef framework (r2 = 0.26). There were no significant changes in either obligate or facultative corallivore abundances at a reference location (Chagos archipelago), highlighting that butterflyfish populations are stable in the absence of habitat disturbance. While specialised coral dependant fishes are highly vulnerable to coral loss caused by climate-induced coral bleaching, the structural collapse of dead coral colonies may have significant, but more variable, impacts across a wide range of fishes. If conservation and mitigation planning are to be effective, there is a clear need to better understand the mechanisms of reef structural collapse and the dynamics of system recovery following large-scale disturbance.

Keywords

Coral reef fishes Ecological versatility Specialisation Erosion Coral reef ecology Coral bleaching Seychelles 

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • N. A. J. Graham
    • 1
    • 2
  • S. K. Wilson
    • 1
    • 2
  • M. S. Pratchett
    • 2
  • N. V. C. Polunin
    • 1
  • M. D. Spalding
    • 3
  1. 1.School of Marine Science & TechnologyNewcastle UniversityNewcastle-upon-TyneUK
  2. 2.ARC Centre of Excellence for Coral Reef StudiesJames Cook UniversityTownsvilleAustralia
  3. 3.Global Marine Team, The Nature Conservancy and Conservation Science GroupDepartment of Zoology, University of CambridgeCambridgeUK