Oecologia

, Volume 182, Issue 2, pp 611–623

Ranavirus could facilitate local extinction of rare amphibian species

  • Julia E. Earl
  • Jordan C. Chaney
  • William B. Sutton
  • Carson E. Lillard
  • Andrew J. Kouba
  • Cecilia Langhorne
  • Jessi Krebs
  • Rebecca P. Wilkes
  • Rachel D. Hill
  • Debra L. Miller
  • Matthew J. Gray
Conservation ecology – original research

DOI: 10.1007/s00442-016-3682-6

Cite this article as:
Earl, J.E., Chaney, J.C., Sutton, W.B. et al. Oecologia (2016) 182: 611. doi:10.1007/s00442-016-3682-6

Abstract

There is growing evidence that pathogens play a role in population declines and species extinctions. For small populations, disease-induced extinction may be especially probable. We estimated the susceptibility of two amphibian species of conservation concern (the dusky gopher frog [Lithobates sevosus] and boreal toad [Anaxyrus boreas boreas]) to an emerging pathogen (ranavirus) using laboratory challenge experiments, and combined these data with published demographic parameter estimates to simulate the potential effects of ranavirus exposure on extinction risk. We included effects of life stage during pathogen exposure, pathogen exposure interval, hydroperiod of breeding habitat, population carrying capacity, and immigration in simulations. We found that both species were highly susceptible to ranavirus when exposed to the pathogen in water at environmentally relevant concentrations. Dusky gopher frogs experienced 100 % mortality in four of six life stages tested. Boreal toads experienced 100 % mortality when exposed as tadpoles or metamorphs, which were the only life stages tested. Simulations showed population declines, greater extinction probability, and faster times to extinction with ranavirus exposure. These effects were more evident with more frequent pathogen exposure intervals and lower carrying capacity. Immigration at natural rates did little to mitigate effects of ranavirus exposure unless immigration occurred every 2 years. Our results demonstrate that disease-induced extinction by emerging pathogens, such as ranavirus, is possible, and that threat may be especially high for species with small population sizes. For the species in this study, conservation organizations should incorporate ranavirus surveillance into monitoring programs and devise intervention strategies in the event that disease outbreaks occur.

Keywords

Amphibian declinesAnaxyrus boreas boreasEndangered speciesIridoviridaeLithobates sevosusMatrix model

Supplementary material

442_2016_3682_MOESM1_ESM.docx (568 kb)
Supplementary Information (DOCX 567 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Julia E. Earl
    • 1
  • Jordan C. Chaney
    • 2
  • William B. Sutton
    • 3
  • Carson E. Lillard
    • 2
  • Andrew J. Kouba
    • 4
    • 8
  • Cecilia Langhorne
    • 5
  • Jessi Krebs
    • 6
  • Rebecca P. Wilkes
    • 7
  • Rachel D. Hill
    • 2
  • Debra L. Miller
    • 2
    • 7
  • Matthew J. Gray
    • 2
  1. 1.Department of Natural Resource Ecology and ManagementOklahoma State UniversityStillwaterUSA
  2. 2.Center for Wildlife Health, Department of Forestry, Wildlife and FisheriesUniversity of TennesseeKnoxvilleUSA
  3. 3.Department of Agricultural and Environmental SciencesTennessee State UniversityNashvilleUSA
  4. 4.Conservation and Research DepartmentMemphis Zoological SocietyMemphisUSA
  5. 5.Department of Biochemistry and Molecular BiologyMississippi State UniversityStarkvilleUSA
  6. 6.Omaha’s Henry Doorly Zoo and AquariumOmahaUSA
  7. 7.Department of Biomedical and Diagnostic Sciences, University of Tennessee College of Veterinary MedicineUniversity of TennesseeKnoxvilleUSA
  8. 8.Department of Wildlife, Fisheries, and AquacultureMississippi State UniversityStarkvilleUSA