In:
Biogeosciences, Copernicus GmbH, Vol. 18, No. 13 ( 2021-07-14), p. 4185-4209
Abstract:
Abstract. Wildfires, as a key disturbance in forest ecosystems, are
shaping the world's boreal landscapes. Changes in fire regimes are closely
linked to a wide array of environmental factors, such as vegetation
composition, climate change, and human activity. Arctic and boreal regions
and, in particular, Siberian boreal forests are experiencing rising air and
ground temperatures with the subsequent degradation of permafrost soils
leading to shifts in tree cover and species composition. Compared to the
boreal zones of North America or Europe, little is known about how such
environmental changes might influence long-term fire regimes in Russia. The
larch-dominated eastern Siberian deciduous boreal forests differ markedly
from the composition of other boreal forests, yet data about past fire
regimes remain sparse. Here, we present a high-resolution macroscopic
charcoal record from lacustrine sediments of Lake Khamra (south-west Yakutia,
Siberia) spanning the last ca. 2200 years, including information about
charcoal particle sizes and morphotypes. Our results reveal a phase of
increased charcoal accumulation between 600 and 900 CE, indicative of
relatively high amounts of burnt biomass and high fire frequencies. This is
followed by an almost 900-year-long period of low charcoal accumulation
without significant peaks likely corresponding to cooler climate
conditions. After 1750 CE fire frequencies and the relative amount of
biomass burnt start to increase again, coinciding with a warming climate and
increased anthropogenic land development after Russian colonization. In the
20th century, total charcoal accumulation decreases again to very low
levels despite higher fire frequency, potentially reflecting a change in
fire management strategies and/or a shift of the fire regime towards more
frequent but smaller fires. A similar pattern for different charcoal
morphotypes and comparison to a pollen and non-pollen palynomorph (NPP) record
from the same sediment core indicate that broad-scale changes in vegetation
composition were probably not a major driver of recorded fire regime
changes. Instead, the fire regime of the last two millennia at Lake Khamra
seems to be controlled mainly by a combination of short-term climate
variability and anthropogenic fire ignition and suppression.
Type of Medium:
Online Resource
ISSN:
1726-4189
DOI:
10.5194/bg-18-4185-2021
DOI:
10.5194/bg-18-4185-2021-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2021
detail.hit.zdb_id:
2158181-2
