Fire and vegetation dynamics in North-West Siberia during the last 60 years based on high-resolution remote sensing

Abstract

Abstract. Rapidly warming Arctic undergoes transitions that can influence global carbon balance. One of the key processes is the shift towards plant species with higher biomass underlining a stronger carbon sink. The shift is predicted by the models based on abiotic climatic factors but it is not always confirmed with observations. Here we use high-resolution remote sensing to study the process of transition of tundra into forest on the 20 000 km2 area in North-West Siberia. Overall, 40 % of the study area was burned during 60-yr period. Three quarters of the burned areas were dry tundra. Ca 10 % of the study area experienced 2–3 fires with an interval of 15–60 years, suggesting a shorter fire return interval than that reported earlier for the northern areas of Central Siberia (130–350 years). Based on our results, the shift in vegetation (within the 60-years period) occurred in 40–85 % of the territories that experienced fires, suggesting a strong role of disturbances for the tree advance. All fire-affected territories were flat, therefore no effect of topography was detected. Oppositely, in the undisturbed areas, tundra-forest transition was observed only in 6–15 % of the territories, characterized by a steeper topographic slope. Our results show that the fires often originated near the centers of anthropogenic activity, which is continuously increasing due to the economic importance of the region. This might explain larger frequency of major fires in the northern territories of West Siberia compared to Central Siberia.

Experience in application and adaptation of the land degradation neutrality concept in the Russian Federation

“…Even for grasslands, a period of 15–20 years is not sufficient for baseline considering the full restoration of natural capital and ecosystem services. In steppe, natural ecosystem regeneration takes at least 50–60 years (Kust et al, 2019), and restoration of natural plant communities and soil cover in disturbed tundra ecosystems takes 40–100 years (Sizov et al, 2020). Regeneration of once disturbed ecosystems is often inhibited by other constant and prolonged disturbances, such as forest and grassland fires, pest invasion, etc.…”

“…Considering that the peak of the negative dynamics of the LDN indicators falls on 0–3 years after clearcutting, and the sustainable recovery of forest stand and biodiversity begins 10–15 years after felling, the periods for establishing LDN baseline indicators are estimated as follows: for carbon flux 15 years, for productivity and biomass stock ‐ up to 100 years, for species diversity and ecosystem >200 years (Figure 6). For tundra, vegetation impacted by wildfires in North‐Western Siberia the minimum period for baseline is determined by a 60‐year cycle (Sizov et al, 2020).…”

“…For the studied PAs themselves, the baseline period of 15 years is sufficient to assess their dynamics in the absence of extreme impacts (Kust et al, 2021). (Lobkovskiy et al 2020b) drew attention to the fact that, in addition to the temporal and ecosystem factors of baseline setting, the duration of baseline period also depends on the spatial and scale fac- by a 60-year cycle (Sizov et al, 2020).…”

“…Studies of LDN dynamics of managed forests in the Russian North (RSF, 2020) estimate that despite NDVI changes in forest land becoming noticeable within 15-20 years after felling and fires, especially in pine forests, full restoration of forests occurs only after 100-150 years, and restoration of ecosystem and species diversity requires at least 200-300 years or more (Figures 7, 8).Even for grasslands, a period of 15-20 years is not sufficient for baseline considering the full restoration of natural capital and ecosystem services. In steppe, natural ecosystem regeneration takes at least 50-60 years(Kust et al, 2019), and restoration of natural plant communities and soil cover in disturbed tundra ecosystems takes 40-100 years(Sizov et al, 2020). Regeneration of once disturbed ecosystems is often inhibited by other constant and prolonged disturbances, such as forest and grassland fires, pest invasion, etc.…”