High adult mortality in disease-challenged frog populations increases vulnerability to drought

Ben C. Scheele, David A. Hunter, Sam C. Banks, Jennifer C. Pierson, Lee F. Skerratt, Rebecca Webb, Don A. Driscoll

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Pathogen emergence can drive major changes in host population demography, with implications for population dynamics and sensitivity to environmental fluctuations. The amphibian disease chytridiomycosis, caused by infection with the fungal pathogen Batrachochytrium dendrobatidis (Bd), is implicated in the severe decline of over 200 amphibian species. In species that have declined but not become extinct, Bd persists and can cause substantial ongoing mortality. High rates of mortality associated with Bd may drive major changes in host demography, but this process is poorly understood.

Here, we compared population age structure of Bd-infected populations, Bd-free populations and museum specimens collected prior to Bd emergence for the endangered Australian frog, Litoria verreauxii alpina (alpine tree frog). We then used population simulations to investigate how pathogen-associated demographic shifts affect the ability of populations to persist in stochastic environments.

We found that Bd-infected populations have a severely truncated age structure associated with very high rates of annual adult mortality. Near-complete annual adult turnover in Bd-infected populations means that individuals breed once, compared with Bd-free populations where adults may breed across multiple years.

Our simulations showed that truncated age structure erodes the capacity of populations to withstand periodic recruitment failure; a common challenge for species reproducing in uncertain environments.

We document previously undescribed demographic shifts associated with a globally emerging pathogen and demonstrate how these shifts alter host ecology. Truncation of age structure associated with Bd effectively reduces host niche width and can help explain the contraction of L.�v.�alpina to perennial waterbodies where the risk of drought-induced recruitment failure is low. Reduced capacity to tolerate other sources of mortality may explain variation in decline severity among other chytridiomycosis-challenged species and highlights the potential to mitigate disease impacts through minimizing other sources of mortality.

Original languageEnglish
Pages (from-to)1453-1460
Number of pages8
JournalJournal of Animal Ecology
Volume85
Issue number6
DOIs
Publication statusPublished - 1 Nov 2016
Externally publishedYes

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frog
frogs
population growth
vulnerability
age structure
drought
mortality
pathogen
demography
amphibian
pathogens
contraction
museum
simulation
amphibians
niche
population dynamics
turnover
demographic statistics
ecology

Cite this

Scheele, B. C., Hunter, D. A., Banks, S. C., Pierson, J. C., Skerratt, L. F., Webb, R., & Driscoll, D. A. (2016). High adult mortality in disease-challenged frog populations increases vulnerability to drought. Journal of Animal Ecology, 85(6), 1453-1460. https://doi.org/10.1111/1365-2656.12569
Scheele, Ben C. ; Hunter, David A. ; Banks, Sam C. ; Pierson, Jennifer C. ; Skerratt, Lee F. ; Webb, Rebecca ; Driscoll, Don A. / High adult mortality in disease-challenged frog populations increases vulnerability to drought. In: Journal of Animal Ecology. 2016 ; Vol. 85, No. 6. pp. 1453-1460.
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Scheele, BC, Hunter, DA, Banks, SC, Pierson, JC, Skerratt, LF, Webb, R & Driscoll, DA 2016, 'High adult mortality in disease-challenged frog populations increases vulnerability to drought', Journal of Animal Ecology, vol. 85, no. 6, pp. 1453-1460. https://doi.org/10.1111/1365-2656.12569

High adult mortality in disease-challenged frog populations increases vulnerability to drought. / Scheele, Ben C.; Hunter, David A.; Banks, Sam C.; Pierson, Jennifer C.; Skerratt, Lee F.; Webb, Rebecca; Driscoll, Don A.

In: Journal of Animal Ecology, Vol. 85, No. 6, 01.11.2016, p. 1453-1460.

Research output: Contribution to journalArticleResearchpeer-review

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