1. The fungal disease white-nose syndrome (WNS) has caused mass mortality in some species of North American bats during hibernation.

2. We use population viability models to test if a hypothetical WNS treatment or management action could facilitate the recovery of WNS-affected little brown myotis (Myotis lucifugus) populations. We modelled scenarios altering three parameters: (1) WNS severity (population growth rate of WNS-affected populations; λ_WNS); (2) proportion of population treated; and (3) treatment improvement in winter survival (TIWS).

3. Our models predict that a treatment or management action that targets an entire population with a TIWS of 40% (the average TIWS in bat trials to date) will cause a population to stabilize or increase if WNS causes an annual decline of less than 70% (i.e. λ_WNS>=0.30). However, for severe WNS (λ_WNS=0.10), the TIWS must be at least 54% to cause the population to stabilize or increase. Where only a proportion of a WNS-affected population is treated, population stability is much harder to achieve unless the impact of WNS attenuates over time.

4. Our models suggest that a treatment or management action only facilitates the recovery of WNS-affected populations if WNS is mild, a large proportion of bats can be treated, TIWS is high, and/or WNS severity attenuates over time.

5. Synthesis and applications. We modelled the predicted abundance trajectory of white-nose syndrome (WNS)-affected little brown myotis (Myotis lucifugus) populations in response to hypothetical treatment or management actions. Our two types of models incorporate the complete range of possible scenarios varying three parameters: (1) population growth rate of the WNS-affected population, (2) the improvement in winter survival associated with the treatment or management action, and (3) the proportion of the population treated. We suggest that our models, which can be explored using online Shiny applications, should be used in the planning phase of treatment or management action programs for WNS.

We have provided annotated R script (wns_modelling_script.R) for models 1, 2a, and 2b, and their associated Shiny apps.