Age truncation due to disease shrinks metapopulation viability for amphibians.

Autor: Heard GW; Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia.; Centre for Biodiversity and Conservation Science, The University of Queensland, St Lucia, Queensland, Australia.; Terrestrial Ecosystem Research Network, The University of Queensland, Long Pocket, Queensland, Australia., Scroggie MP; Department of Energy, Environment and Climate Action, Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria, Australia., Hollanders M; Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia.; Quantecol, Ballina, New South Wales, Australia., Scheele BC; Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia.
Jazyk: angličtina
Zdroj: The Journal of animal ecology [J Anim Ecol] 2024 Nov; Vol. 93 (11), pp. 1670-1683. Date of Electronic Publication: 2024 Sep 17.
DOI: 10.1111/1365-2656.14177
Abstrakt: Metapopulations often exist in a fragile balance between local extinctions and (re)colonisations, in which case emerging threats that alter species vital rates may drastically increase metapopulation extinction risk. We combined empirical data with metapopulation simulations to examine how demographic shifts associated with amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) have altered metapopulation viability for threatened amphibians in Australia. Comparing the ages of museum specimens collected before Bd emerged in Australia with individuals from geographically matched remnant populations revealed significant truncation of age structures post-Bd, with a halving of annual adult survival probabilities. Spatially realistic metapopulation modelling demonstrated that reduced adult survival led to major reductions in the parameter space over which persistence was possible for the focal species, with contractions to landscapes with higher landscape connectivity, lower environmental stochasticity and considerably higher recruitment rates. Metapopulation persistence post-Bd required greater landscape connectivity than pre-Bd. This arises from a landscape-level analogue of compensatory recruitment at the population level, in which higher (re)colonisation rates can offset more frequent local extinctions, enabling persistence of amphibians susceptible to Bd. Interactions between recruitment rate, environmental stochasticity and landscape connectivity were also more important for metapopulation persistence post-Bd. Higher recruitment was required to mitigate the impacts of environmental stochasticity, and higher landscape connectivity was required to mitigate the impacts of environmental stochasticity and poor recruitment. Increased reliance on these interdependencies shrunk the parameter space over which metapopulations could persist post-Bd. Our study demonstrates that emerging threats that alter species vital rates can drastically reduce the capacity of certain environments to support metapopulations. For our focal species, reductions in adult survival rates due to Bd produced major reductions in the conditions under which persistence was possible, providing a mechanistic insight into the processes underpinning observed range and niche contractions of amphibians impacted by this pathogen. More broadly, our study illustrates how environmentally mediated host resilience can enable persistence following the emergence of novel pathogens. This pathway to persistence is worthy of greater attention on both conceptual and applied grounds.
(© 2024 The Author(s). Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.)
Databáze: MEDLINE
Externí odkaz: