From flames to inflammation: how wildfires affect patterns of wildlife disease

Abstract

Background Fire strongly affects animals’ behavior, population dynamics, and environmental surroundings, which in turn are likely to affect their immune systems and exposure to pathogens. However, little work has yet been conducted on the effects of wildfires on wildlife disease. This research gap is rapidly growing in importance because wildfires are becoming globally more common and more severe, with unknown impacts on wildlife disease and unclear implications for livestock and human health in the future. Results Here, we discussed how wildfires could influence susceptibility and exposure to infection in wild animals, and the potential consequences for ecology and public health. In our framework, we outlined how habitat loss and degradation caused by fire affect animals’ immune defenses, and how behavioral and demographic responses to fire affect pathogen exposure, spread, and maintenance. We identified relative unknowns that might influence disease dynamics in unpredictable ways (e.g., through altered community composition and effects on free-living parasites). Finally, we discussed avenues for future investigations of fire-disease links. Conclusions We hope that this review will stimulate much-needed research on the role of wildfire in influencing wildlife disease, providing an important source of information on disease dynamics in the wake of future wildfires and other natural disasters, and encouraging further integration of the fields of fire and disease ecology.

Short‐term impact of a wildfire on the homeostasis of Tropidurus oreadicus lizards

“…Habitat disturbance is often the first and most severe of fire's effects. Depending on the type, severity, and extent of the fire, it may burn vegetation widely, reducing access to shade and shelter such that surviving individuals have fewer opportunities to eat, nest, thermoregulate, and hide from predators (Albery et al, 2021; Block et al, 2016; Wan et al, 2020). In fire‐prone environments reptile homeostasis must be adapted modulating energy allocation to locomotor performance, foraging behavior, growth rate, and sexual ornamentation, among other individual factors (Brisson et al, 2003; Howey et al, 2016; Weiss & Brower, 2021; Wild & Gienger, 2018).…”

“…These could directly affect animal immune systems (Becker et al, 2020) or other physiological systems, such as the ability to thermoregulate, with additional indirect impacts on immunity and infection prevalence (Bower et al, 2019; Zimmerman, 2020). Diseases are, therefore, a potential contributor to reduced fitness in fire‐altered landscapes that deserve further investigation (Albery et al, 2021; Scasta, 2015).…”

Messaging Should Reflect the Nuanced Relationship between Land Change and Zoonotic Disease Risk

“…But some differences in risk are intuitive. Burning vegetation, for example, involves minimal human–wildlife contact and decreases the abundance of some pathogens (Albery et al 2021 ), although smoke may help to spread others (Kobziar and Thompson 2020 ). Logging, on the other hand, more predictably exposes people to wildlife and their pathogens and for longer (Faust et al 2018 ).…”

Pre‐fire grazing and herbicide treatments can affect post‐fire vegetation in a Great Basin rangeland

“…Reid et al, 2016; Xu et al, 2020). The environmental effects of fire are also profound and can include an increase in erosion, pollution of local water sources, and changes in wildlife disease dynamics (Albery et al, 2021; Smith et al, 2011). In arid rangeland systems lacking a historical fire regime characterized by frequent fires, wildfire has been particularly detrimental to biodiversity due to its enhancement of aggressive invasive plant species, resulting in a cascade of negative effects on extant native plant communities and the wildlife that depend on them (Balch et al, 2013).…”