No abstract

Wildfires are a naturally rare phenomenon in subarctic tundra ecosystems. Climate change triggers feedback loops that probably increase fire frequency and extent in those regions. Fire can change ecosystem properties of the Arctic tundra. However, long-term effects of fire on vegetation dynamics are still poorly understood.We studied soil and vegetation patterns of three fire scars (>44, 28 and 12 years old), situated at the northern border of the forest tundra ecozone within the Yamalo-Nenets Autonomous Okrug in Western Siberia, Russia.Lichen cover was lower on burnt compared with unburnt plots, while bryophyte and shrub cover was higher. Those effects were still apparent more than four decades after fire.Betula nana showed enhanced growth of individual plants after burning, indicating increased vitality and growth potential, due to modified ecosystem processes after fire: While the active layer and soil temperatures returned to levels comparable with unburned plots after 44 years, shrub growth was still enhanced. This reveals a strong fire legacy effect and can reinforce shrub encroachment with far reaching impacts on the ecosystem.

No abstract

Fire is an important ecological and evolutionary force that has shaped the world's terrestrial ecosystems for millennia, strongly influencing biodiversity patterns in fire-prone landscapes (He et al., 2019); however, fire regimes are being altered by anthropogenic drivers, leading to modifications in ecosystem composition (Kelly et al., 2020). Arctic and subarctic ecosystems experience wildfire events less often than other biomes (Archibald et al., 2013;Viereck & Schandelmeier, 1980), but climate change is expected to increase fire frequency and extent at high latitudes (Hu et al., 2015;Moskovchenko et al., 2020).