Environmental pathogen reservoirs exist for many globally important diseases and can fuel epidemics, influence pathogen evolution, and increase the threat of host extinction. Species composition can be an important factor that shapes reservoir dynamics and ultimately determines the outcome of a disease outbreak. However, disease‐induced mortality can change species communities, indicating that species responsible for environmental reservoir maintenance may change over time. Here we examine reservoir dynamics of Pseudogymnoascus destructans, the fungal pathogen that causes white‐nose syndrome in bats. We quantified changes in pathogen shedding, infection prevalence and intensity, host abundance, and the subsequent propagule pressure imposed by each species over time. We find that highly shedding species are important during pathogen invasion, but contribute less over time to environmental contamination as they also suffer the greatest declines. Less infected species remain more abundant, resulting in equivalent or higher propagule pressure. More broadly, we demonstrate that high infection intensity and subsequent mortality during disease progression can reduce the contributions of high shedding species to long‐term pathogen maintenance.This article is protected by copyright. All rights reserved.

Environmental pathogen reservoirs exist for many globally important diseases and can fuel disease outbreaks, affect pathogen evolution, and increase the threat of host extinction. Differences in pathogen shedding among hosts can create mosaics of infection risk across landscapes by increasing pathogen contamination in high use areas. However, how the environmental reservoir establishes in multi-host communities and the importance of factors like host-specific infection and abundance in environmental contamination and transmission remain important outstanding questions. Here we examine how Pseudogymnoascus destructans, the fungal pathogen that causes white-nose syndrome in bats, invades and establishes in the environment. We quantified dynamic changes in pathogen shedding, infection intensities, host abundance, and the subsequent propagule pressure imposed by each species within the community. We find that the initial establishment of the pathogen reservoir is driven by different species within the community than those that are responsible for maintaining the reservoir over time. Our results also show that highly shedding species do not always contribute the most to pathogen reservoirs. More broadly, we demonstrate how individual host shedding rates scale to influence landscape-level pathogen contamination.

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Understanding host persistence with emerging pathogens is essential for conserving populations. Hosts may initially survive pathogen invasions through pre-adaptive mechanisms. However, whether pre-adaptive traits are directionally selected to increase in frequency depends on the heritability and environmental dependence of the trait and the costs of trait maintenance. Body condition is likely an important pre-adaptive mechanism aiding in host survival, although can be seasonally variable in wildlife hosts. We used data collected over seven years on bat body mass, infection, and survival to determine the role of host body condition during the invasion and establishment of the emerging disease, white-nose syndrome. We found that when the pathogen first invaded, bats with higher body mass were more likely to survive, but this effect dissipated following the initial epizootic. We also found that heavier bats lost more weight overwinter, but fat budgeting depended on infection severity. Lastly, we found little support that bat mass increased in the population after pathogen arrival, and there was high annual plasticity in individual bat masses. Overall, our results suggest that factors that contribute to host survival during pathogen invasion may diminish over time, and are potentially replaced by other host adaptations.