Landscape fires disproportionally affect areas of conservation priority but only under low moisture conditions

Author(s): Kirkland, M., Atkinson, P.W., Pearce-Higgins, J.W., De Jong, M., Dowling, T.P.F., Grummoe, D., Critchley, M. & Ashton-Butt, A.

Published: May 2023

Journal: Science of The Total Environment Volume: 884

Article No.: 163849

Digital Identifier No. (DOI): 10.1016/j.scitotenv.2023.163849

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In this study, BTO scientists mapped large fires that occurred over a 19-year period in Polesia, a region containing some of Europe’s last pristine peatlands and lowland forests in Eastern Europe. Fires are of great concern to policymakers in the region due to the economic and health costs, and a lot of resources are used to suppress fires during hot and dry years. There are potentially natural solutions to fires, however, that could also benefit birds, biodiversity and climate issues. These ‘nature-based’ solutions include restoring drained wetlands. In this study, freely-available satellite data were used to explore the prevalence of large fires and the factors causing them. This allowed researchers to explore whether restoring the landscape’s wetlands could reduce the increasing risk of large, damaging fires as the climate changes.

This study identified five fires reaching more than 100 km², a threshold often used to classify ‘megafires’. Frequent spring and summer fires predominantly started in agricultural areas, where farmers burn the land to clear it, both before planting and following the harvest. However, these fires often spread into neighbouring peatlands and floodplain meadows, endangering threatened wildlife, such as the Greater Spotted Eagle and Aquatic Warbler, and damaging a globally important carbon sink. The largest fires burned in native deciduous forests, threatening protected old-growth oak and beech forests, which are more vulnerable and less likely to recover than more fire-adapted trees. Overall, more than one fifth of protected land burned. This is compared with 8% of unprotected land. One fire reached 97 km² and burned significant areas of the Chernobyl Exclusion Zone, where radioactive contamination from the Chernobyl 1986 disaster is highest, and where the impacts of large fires on human health may be particularly severe.

The results of the study suggest that landscape restoration in Polesia’s wetlands would help to limit the spread and intensity of unnaturally large, damaging fires, while reinstating natural, periodic low-intensity fires, providing ecosystem benefits and supporting long-term carbon storage. Throughout Europe, including in Polesia, years of drainage for agriculture and commercial forestry has created overgrown, drier landscapes that are more susceptible to fires. This study showed that open peatlands, meadows, and deciduous forests were far more likely to burn when moisture conditions in the soil and litter were low. In contrast, peatlands were very unlikely to burn under high moisture conditions. Preserving and restoring large, intact, well-hydrated peatlands would help to create natural barriers to large, severe fires, while reinstating periodic low-intensity fires. Doing so would provide ecosystem and conservation benefits, support long-term carbon storage and help tackle climate change, and protect human lives.

Abstract

Landscape fires are a natural component of the Earth System. However, they are of growing global concern due to climate change exacerbating their multiple impacts on biodiversity, ecosystems, carbon storage, human health, economies, and wider society. Temperate regions are predicted to be at greatest risk of increasing fire activity due to climate change, where fires can seriously impact important ecosystems for biodiversity and carbon storage, such as peatlands and forests. There is insufficient literature on the background prevalence, distribution, and drivers of fires in these regions, especially within Europe, to assess and mitigate their risks. Using a global database of fire patches based on the MODIS FireCCI51 product, we address this knowledge gap by quantifying the current prevalence and size of fires in Polesia, a 150,000 km² area comprising a mosaic of peatland, forest, and agricultural habitats in northern Ukraine and southern Belarus. Between 2001 and 2019, fires burned 31,062 km² of land, and were most frequent in spring and autumn. Although most fires started in agricultural land, fires disproportionately affected natural and semi-natural land cover types, particularly in protected areas. Over one fifth of protected land burned. Coniferous forests were the most common land cover type in protected areas, but fires mostly occurred in meadows, open peatlands (especially fen and transition mires), and native deciduous forests. These land cover types were highly susceptible to fires under low soil moisture conditions, but the risk of fire was low under average or higher soil moisture conditions. Restoring and maintaining natural hydrological regimes could be an effective nature-based solution to increase the resilience of fire-vulnerable ecosystems and support global biodiversity and carbon storage commitments under the United Nations Framework Conventions on Climate Change and Convention on Biological Diversity.

Notes

The authors acknowledge support from BTO and the Endangered Landscapes Programme (ELP). ELP is managed by the Cambridge Conservation Initiative and is funded by Arcadia, a charitable fund of LisbetRausing and Peter Baldwin. Thanks to Wentao Chen and Florent Mouillot of Le Centre National de la Recherche Scientifique. Their input was invaluable in the acquiring and preparation of the fire data. Thanks to Neil Wilyman and Susana Baena for their technical input.

Staff Author(s)