Quantitative support for the benefits of proactive management for wildlife disease control

Finding effective pathogen mitigation strategies is one of the biggest challenges humans face today. In the context of wildlife, emerging infectious diseases have repeatedly caused widespread host morbidity and population declines of numerous taxa. In areas yet unaffected by a pathogen, a proactive management approach has the potential to minimize or prevent host mortality. However, we typically lack critical information on the disease dynamics in a novel host system, have limited empirical evidence on efficacy of management interventions, and lack validated predictive models. As such, quantitative support for identifying effective management interventions is largely absent, and the opportunity for proactive management is often missed. Here, we consider the potential invasion of the chytrid fungus, Batrachochytrium salamandrivorans, whose expected emergence in North America poses a severe threat to hundreds of salamander species in this global salamander biodiversity hotspot. We developed and parameterized a dynamic multi-state occupancy model to forecast host and pathogen occurrence, following expected emergence of the pathogen, and evaluated the response of salamander populations to different management scenarios. Our model forecasts that taking no action is expected to be catastrophic to salamander populations. We also show that proactive action is expected to maximize host occupancy outcomes compared to ‘wait and see’ reactive management, thus providing quantitative support for proactive management opportunities. Additionally, we found that Bsal eradication is unlikely under any evaluated management options. Contrary to our expectations, even early pathogen detection had little effect on Bsal or host occupancy outcomes. Our analysis provides quantitative support that proactive management is the optimal strategy for promoting persistence of disease-threatened salamander populations. Our approach fills a critical gap by defining a framework for evaluating management options prior to pathogen invasion and can thus serve as a template for addressing novel disease threats that jeopardize wildlife and human health.

Methods
USGS Disclaimer

Unless otherwise stated, all data, metadata, and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty.

Data Description

These data consist of the raw estimates and confidence values that were collected by expert elicitation from 35 experts to provide estimates for 158 model parameters of our develop multi-state occupancy model considering no management, 10 proactive actions and 10 reactive actions.