Welcome to the Pyrocene: Animal survival in the age of megafire

Abstract

Planet Earth is entering the age of megafire, pushing ecosystems to their limits and beyond. While fire causes mortality of animals across vast portions of the globe, scientists are only beginning to consider fire as an evolutionary force in animal ecology. Here, we generate a series of hypotheses regarding animal responses to fire by adopting insights from the predator–prey literature. Fire is a lethal threat; thus, there is likely strong selection for animals to recognize the olfactory, auditory, and visual cues of fire, and deploy fire avoidance behaviours that maximize survival probability. If fire defences are costly, it follows that intraspecific variation in fire avoidance behaviours should correspond with variation in fire behaviour and regimes. Species and populations inhabiting ecosystems that rarely experience fire may lack these traits, placing ‘fire naive’ populations and species at enhanced extinction risk as the distribution of fire extends into new ecosystem types. We outline a research agenda to understand behavioural responses to fire and to identify conservation interventions that could be used to overcome fire naivety.

A review of the effects of wildfire smoke on the health and behavior of wildlife

“…Wildlife across taxa, including insects, reptiles, and mammals, rely on smoke as a cue to engage in fire avoidance behaviors (Nimmo et al 2021). Insects may relocate after detecting smoke to evade fires.…”

“…In fact, animal models, including mice, rats, rabbits, sheep, and monkeys, are often used to study the onset and progression of human disease following exposure to the toxic gases and aerosols found in smoke (David et al 2009). Although many animals in fire-prone habitats are able to detect and avoid wildfires, fires still pose direct threats to wildlife (Engstrom 2010, Nimmo et al 2021), including exposure to extreme heat and smoke. Yet, the impacts of wildfire smoke on the health and behavior of wildlife are largely unknown (Hovick et al 2017, Lee et al 2017, Erb et al 2018, Geiser et al 2018.…”

“…ecology, physiology, animal behavior, veterinary medicine, etc); as such, ecologists, wildlife managers, and other stakeholders may be challenged to identify relevant studies. To date, review papers have synthesized findings on firstorder effects of fire on animals, including injury, morbidity, and mortality (Engstrom 2010), considered behavioral responses of mammals to fire, specifically torpor (Geiser et al 2018), and discussed fire as an evolutionary force driving animal behavior and survival (Nimmo et al 2021), but none have focused specifically on the effects of smoke from wildfires on the health and behavior of wildlife.…”

Transcending the disaster paradigm: Understanding persistence of animal populations in fire‐prone environments

“…Trait variability is also critical to persistence and adaptation under shifting fire regimes as climate change rapidly unfolds (Kelly et al, 2020). Nimmo et al (2021) identify several productive areas for future inquiry, including how behavioural responses to fire cues vary among individuals, populations and species, the drivers of this variability, and whether different cues elicit different behavioural responses. As well as improving understanding of survival through fire events, behavioural traits of animals are likely to provide important insights into other mechanisms that govern persistence under different fire regimes (Santos et al, in review).…”

“…The extension of predator-prey theory to fire responses (Nimmo et al, 2021) addresses a large and longstanding gap in understanding the diversity of ecological mechanisms that enable persistence and proliferation of some species and not others under particular fire regimes. Like perspectives of fire as a global herbivore (Bond & Keeley, 2005), it should help to transcend the disaster paradigm, produce new insights on ecology and evolution of flammable ecosystems, and improve our ability to predict and reduce fire-related extinction risks of animals in a changing climate.…”