Siberian tundra ecosystem vegetation and carbon stocks four decades after wildfire

Abstract

Tundra ecosystem fire regimes are intensifying with important implications for regional and global carbon (C) and energy dynamics. Although a substantial portion of the tundra biome is located in Russia, the vast majority of accessible studies describe North American tundra fires. Here we use field observations and high-resolution satellite remote sensing observations to describe the effects of wildfire on ecosystem C pools and vegetation communities four decades after fire for a tundra ecosystem in northeastern Siberia. Our analyses reveal no differences between soil physical properties and C pools in burned and unburned tundra, which we attribute to low combustion of organic soil associated with low-severity fire. Field and remote sensing data show no differences in aboveground C pools and vegetation communities indicating recovery to prefire conditions. These results are comparable to observations of ecosystem recovery in North American tundra. An assessment of literature data indicate that the average annual area burned in Russian tundra is an order of magnitude larger than that of Alaskan tundra, highlighting a crucial need to assess Russian tundra fire regimes in order to understand the current and future role of the biome wide fire regime in regional and global C and energy dynamics.

Remote Sensing of Landscape Change in Permafrost Regions

“…Loranty et al . () found that while some of the best‐documented tundra fires are located in Alaska, a large proportion of global tundra fires actually happen in Russia, with an average annual area burned of 331 200 ha/yr in Russia versus 21 400 ha/yr in Alaska for 1950–2011. Beck et al .…”

“…Severe fire seasons in Alaska in 2004 (2.7 M ha burn area) and 2015 (2.1 M ha), in Canada in 2015 (4.0 M ha), and in 2012 in Russia (30 M ha) have led to concern of increased fire frequency in response to climate warming (Kasischke et al, 2010). Loranty et al (2014) found that while some of the bestdocumented tundra fires are located in Alaska, a large proportion of global tundra fires actually happen in Russia, with an average annual area burned of 331 200 ha/yr in Russia versus 21 400 ha/yr in Alaska for 1950-2011. used MODIS imagery to calculate the deciduous fraction of burn scars and normalised burn ratio, along with maps of burned areas, albedo and forest biomass, to conclude that more severely burned areas in interior Alaska since the 1950s have shifted toward greater deciduous biomass. An assessment of vegetation succession along the century-scale chronosequence of tundra fire disturbances from 1880 to 2007 manually interpreted using satellite imagery from arctic Alaska found that tundra fires facilitated shrub expansion (Jones et al, 2013b).…”

Spatial variation in vegetation productivity trends, fire disturbance, and soil carbon across arctic-boreal permafrost ecosystems

“…At the same time, loss of labile carbon coupled with microbial community and abiotic changes may limit decomposition following fire (Taş et al 2014). Recovery of vegetation and soil accumulation after fire can promote permafrost aggradation enabling recovery of active layer depths to pre-fire conditions (Mackay 1995, Viereck et al 2008, Rocha et al 2012, Loranty et al 2014. In the discontinuous zone, permafrost is often thermally protected by denser vegetation canopies and deeper soil organic layers, meaning disturbance that removes these insulating layers may lead to greater thawing of permafrost (Jorgenson et al 2010).…”

Circumpolar spatio-temporal patterns and contributing climatic factors of wildfire activity in the Arctic tundra from 2001–2015

“…Also, fire events in the boreal forest have been studied more rigorously than tundra fires, partly due to the tundra's extreme environmental conditions . However, with the recent availability of observational data of global fire disturbances, tundra fires have started to receive considerable attention , Liu et al 2014, Loboda et al 2013, Loranty et al 2014, as these fires can play a significant role in global positive climate feedback mechanisms (Bret-harte et al 2013) and perturbations to ecosystem processes . Despite this, existing studies of tundra fires suffer from spatially restricted paleofire records as well as short observational fire records (Stocks et al 1998(Stocks et al , 2003, which limit a comprehensive understanding of the spatial variability of tundra wildfire characteristics (i.e.…”