Wildfires are a large-scale phenomenon that affects ecosystems around the world. Although wildfires can have destructive impacts on habitats and the biota they support, wildfires also enable many ecosystem services and are frequently prescribed to benefit biodiversity.
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The Role of Wildfires and their Extent in the Modern World
Whether it is human-caused or natural, wildfires have always been a major concern around the world. Recent studies have also shown that areas affected by wildfires are increasing. In 2020 alone, the amount of burnt area worldwide has increased by 376% compared to the annual average between 2003–2019.
Moreover, nearly half of that area (43%; over 17,200 km2) had not been burnt from 2003–2019, showing that fires are affecting new areas. Already in 2021, unprecedented wildfires have occurred in California, Australia, and Greece, impacting ecosystems and humans. The increased rates of occurrence are associated with increased global temperatures, heatwaves, and droughts, as well as intensive agricultural land use and insufficient budgets supplying fire management services.
In a 2021 review, Haque et al. discussed the impacts of the 2020 wildfires in Australia, and the hazardous effects of these bushfires on human society and the environment, particularly how these unparalleled fires impacted areas previously unaffected by wildfires. The review compiled data on strategies to mitigate such fires and highlighted how bushfires are 'necessary evils' that can benefit the environment. Indeed, although wildfires are known to cause extensive economic and environmental consequences, wildfires are also important natural phenomena.
Solving the Biodiversity Crisis
The Ecosystem Services and Impacts Associated with Wildfires
In a 2019 review by Pausas and Keeley, the authors describe how the use of fire has greatly benefited human societies throughout history. From cooking to the provision of heat and light, fire was rapidly seen as a benefit for early humans. From the onset of agricultural lifestyles, fire was also used as a tool for deforestation to create farmland, but in the last century, it has also been used as a strategy to manage forests.
Although the perception of wildfires is overwhelmingly negative, authors of the study group the ecosystem services derived from wildfires into four categories. Specifically, wildfires support, provision, regulate, and provide cultural services.
Firstly, wildfires generate open habitats for a diversity of light-loving plants and animals; these species offer a range of goods and services (food, fiber, pollination, tourism, hunting) to humans. Secondly, there are many provisioning, regulating, and cultural services that people obtain from wildfires, and prescribed fires and wildfire management are tools for mimicking the ancestral role of wildfires in an increasingly populated world. Finally, wildfires help control pests and prevent larger catastrophic fires, hence contributing to the regulation of biogeochemical cycles, and can benefit plants adapting to novel climates.
Indeed, prescribed fires can sometimes be used to replace the original role of wildfires. This is of growing importance given the rise of global temperatures and the increase in heatwaves' frequency, severity, and duration. However, the effect of prescribed fires on biodiversity is not straightforward.
Finer scale effects on ecosystems and the species they encompass were examined by Pastro et al., 2011. The study considered the hypothesis that small-scale prescribed fires maximize biodiversity by creating heterogeneous mixes of early-, mid-, and late-successional habitats across the landscape. From data on Australian grassland habitats, the authors used diversity indices to assess the effects of prescribed fires before and after.
Authors found that fires of differing spatial scales and heterogeneity affected diversity in different ways and that the effects were species-dependent. Findings demonstrated that prescribed fires did not increase diversity considerably, as the initial hypothesis suggested, but increased diversity was noted with stochastic events such as rainfalls that occurred after fires.
Nevertheless, despite little utility for conservation, authors did iterate that prescribed fires may help create fire breaks that serve to protect the habitats of fire-sensitive species from the effects of broadscale wildfire. Harnessing the power of wildfires should therefore be done with caution, and although wildfires can be associated with some benefits, human-induced fires, even when prescribed, may be less beneficial than expected.
Fires can kindle biodiversity, sparking new approaches to conservation
Wildfires in an Era of Climate Change
Looking into the future, the effects of wildfires are of particular concern due to global climate change. Specifically, rising temperatures will increase aridity, the severity, and frequency of heatwaves which can induce large-scale droughts, increasing the probability and severity of fires. Managing the risk and severity of fires is therefore becoming increasingly important.
This was discussed in further detail in a 2021 study by Rakhmatulina et al., who modeled the impacts of prescribed fires under projected future climates. The authors considered the effects of prescribed fires on vegetation trajectories post-fires and the effects on water flow. Findings showed more prescribed fires increased water flow under various climate projections, demonstrating that increased fire frequency speeds up hydrologic changes.
Understanding the future effects of wildfires and prescribed fires is of key importance to managing areas susceptible to large-scale fires. Further research on post-fire effects, such as the one by Rakhmatulina et al. could also provide insights into the benefits of fires in certain areas, which can then be used to mitigate some of the effects of anthropogenic activities on ecosystems. Ultimately, better management of wildfires will prevent economic and ecological disasters often associated with wildfires, which could then lead to changes in public perception that could reveal the benefits of fires.
Sources:
- Garcia, L. C., Szabo, J. K., de Oliveira Roque, F., de Matos Martins Pereira, A., Nunes Da Cunha, C., Damasceno-Júnior, G. A., Morato, R. G., Tomas, W. M., Libonati, R., & Ribeiro, D. B. (2021). Record-breaking wildfires in the world's largest continuous tropical wetland: Integrative fire management is urgently needed for both biodiversity and humans. Journal of Environmental Management, 293, 112870. https://doi.org/10.1016/j.jenvman.2021.112870
- Haque, M. K., Azad, M. A. K., Hossain, M. Y., Ahmed, T., Uddin, M., & Hossain, M. M. (2021). Wildfire in Australia during 2019–2020, Its Impact on Health, Biodiversity and Environment with Some Proposals for Risk Management: A Review. Journal of Environmental Protection, 12(06), 391–414. https://doi.org/10.4236/jep.2021.126024
- Pastro, L. A., Dickman, C. R., & Letnic, M. (2011). Burning for biodiversity or burning biodiversity? Prescribed burn vs. wildfire impacts on plants, lizards, and mammals. Ecological Applications, 21(8), 3238–3253. https://doi.org/10.1890/10-2351.1
- Pausas, J. G., & Keeley, J. E. (2019). Wildfires as an ecosystem service. Frontiers in Ecology and the Environment, 17(5), 289–295. https://doi.org/10.1002/fee.2044
- Rakhmatulina, E., Boisramé, G., Stephens, S. L., & Thompson, S. (2021). Hydrological benefits of restoring wildfire regimes in the Sierra Nevada persist in a warming climate. Journal of Hydrology, 593, 125808. https://doi.org/10.1016/j.jhydrol.2020.125808
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