Eurasian Taiga Research Articles

Landscape structure of the territory of the Kilemarsky section of the projected National Park Nizhegorodskoe Zavolzh'e (Nizhny Novgorod Region, Russia)

The article presents the results of landscape differentiation of the territory of the Kilemarsky section of the projected National Park Nizhegorodskoe Zavolzh'e, performed at the hierarchical level of landscape types. The territory of the Kilemarsky section of the projected national park lies in the Eurasian taiga (coniferous forest) botanico-geographical area, in the subzone of the southern taiga. According to the botanico-geographical zoning of the European part of Russia, its territory belongs to the Kama-Pechera-West Ural subprovincion of the Ural-West Siberian taiga province. The specifics of the national park's operating mode require functional zoning of the territory, taking into account the vulnerability of natural complexes, permissible recreational pressure and areas of propagation of rare plant and animal species, which determines the high demand for landscape zoning schemes, necessary for the effective organization of environmental and recreational activities. The article presents a scheme of landscape zoning of the territory of one of the five sections of the projected National Park Nizhegorodskoe Zavolzh'e – Kilemarsky. The work was carried out on the basis of field and desk researches, conducted in 2022. During the research seven landscapes were identified and briefly characterized.

An Early Neolithic Sanctuary in the Eastern Irtysh Basin

We describe the findings of excavations at an unusual sanctuary in the Baraba forest-steppe. It is a structure consisting of a ditch encircling the presumed sacral space, and a system of pits containing non-utilitarian artifacts. Pits in the bottom of the ditch indicate wooden structures, which are not preserved. Descriptions of the features are provided. Artifacts are related to household, manufacturing, and ritual. On the basis of stratigraphy and radiocarbon analysis, relative and absolute chronology is assessed. The site dates to the 7th–6th millennia BC and is associated with the Barabinskaya culture. Parallels with Mesolithic and Neolithic sanctuaries and ritual sites in the Eurasian taiga zone are listed.

A nearly complete database on the records and ecology of the rarest boreal tiger moth from 1840s to 2020

Global environmental changes may cause dramatic insect declines but over century-long time series of certain species’ records are rarely available for scientific research. The Menetries’ Tiger Moth (Arctia menetriesii) appears to be the most enigmatic example among boreal insects. Although it occurs throughout the entire Eurasian taiga biome, it is so rare that less than 100 specimens were recorded since its original description in 1846. Here, we present the database, which contains nearly all available information on the species’ records collected from 1840s to 2020. The data on A. menetriesii records (N = 78) through geographic regions, environments, and different timeframes are compiled and unified. The database may serve as the basis for a wide array of future research such as the distribution modeling and predictions of range shifts under climate changes. It represents a unique example of a more than century-long dataset of distributional, ecological, and phenological data designed for an exceptionally rare but widespread boreal insect, which primarily occurs in hard-to-reach, uninhabited areas of Eurasia.

Genetic Structure and Geographical Differentiation of Larix sibirica Ledeb. in the Urals

The Ural Mountains and the West Eurasian Taiga forests are one of the most important centers of genetic diversity for Larix sibirica Ledeb. Forest fragmentation negatively impacts forest ecosystems, especially due to the impact of their intensive use on the effects of climate change. For the preservation and rational use of forest genetic resources, it is necessary to carefully investigate the genetic diversity of the main forest-forming plant species. The Larix genus species are among the most widespread woody plants in the world. The Siberian larch (Larix sibirica, Pinaceae) is found in the forest, forest-tundra, tundra (Southern part), and forest-steppe zones of the North, Northeast, and partly East of the European part of Russia and in Western and Eastern Siberia; in the Urals, the Siberian larch is distributed fragmentarily. In this study, eight pairs of simple sequence repeat (SSR) primers were used to analyse the genetic diversity and population structure of 15 Siberian larch populations in the Urals. Natural populations in the Urals exhibit indicators of genetic diversity comparable to those of Siberia populations (expected heterozygosity, He = 0.623; expected number of alleles, Ne = 4017; observed heterozygosity, Ho = 0.461). Genetic structure analysis revealed that the examined populations are relatively highly differentiated (Fst = 0.089). Using various algorithms for determining the spatial genetic structure, the examined populations formed three groups according to geographical location. The data obtained are required for the development of species conservation and restoration programs, which are especially important in the Middle Urals, which is the region with strong forest fragmentation.

Carbon balance of a Finnish bog: temporal variability and limiting factors based on 6 years of eddy-covariance data

Abstract. Pristine boreal mires are known as substantial sinks of carbon dioxide (CO2) and net emitters of methane (CH4). Bogs constitute a major fraction of pristine boreal mires. However, the bog CO2 and CH4 balances are poorly known, having been largely estimated based on discrete and short-term measurements by manual chambers and seldom using the eddy-covariance (EC) technique. Eddy-covariance (EC) measurements of CO2 and CH4 exchange were conducted in the Siikaneva mire complex in southern Finland in 2011–2016. The site is a patterned bog having a moss–sedge–shrub vegetation typical of southern Eurasian taiga, with several ponds near the EC tower. The study presents a complete series of CO2 and CH4 EC flux (FCH4) measurements and identifies the environmental factors controlling the ecosystem–atmosphere CO2 and CH4 exchange. A 6-year average growing season (May–September) cumulative CO2 exchange of −61 ± 24 g C m−2 was observed, which partitions into mean total respiration (Re) of 167 ± 33 (interannual range 146–197) g C m−2 and mean gross primary production (GPP) of 228 ± 46 (interannual range 193–257) g C m−2, while the corresponding FCH4 amounts to 7.1 ± 0.7 (interannual range 6.4–8.4) g C m−2. The contribution of October–December CO2 and CH4 fluxes to the cumulative sums was not negligible based on the measurements during one winter. GPP, Re and FCH4 increased with temperature. GPP and FCH4 did not show any significant decline even after a substantial water table drawdown in 2011. Instead, GPP, Re and FCH4 were limited in the cool, cloudy and wet growing season of 2012. May–September cumulative net ecosystem exchange (NEE) of 2013–2016 averaged at about −73 g C m−2, in contrast with the hot and dry year 2011 and the wet and cool year 2012. Suboptimal weather likely reduced the net sink by about 25 g C m−2 in 2011 due to elevated Re, and by about 40 g C m−2 in 2012 due to limited GPP. The cumulative growing season sums of GPP and CH4 emission showed a strong positive relationship. The EC source area was found to be comprised of eight distinct surface types. However, footprint analyses revealed that contributions of different surface types varied only within 10 %–20 % with respect to wind direction and stability conditions. Consequently, no clear link between CO2 and CH4 fluxes and the EC footprint composition was found despite the apparent variation in fluxes with wind direction.

Biogenic volatile organic compound ambient mixing ratios and emission rates in the Alaskan Arctic tundra.

Rapid Arctic warming, a lengthening growing season, and the increasing abundance of biogenic volatile-organic-compound-emitting shrubs are all anticipated to increase atmospheric biogenic volatile organic compounds (BVOCs) in the Arctic atmosphere, with implications for atmospheric oxidation processes and climate feedbacks. Quantifying these changes requires an accurate understanding of the underlying processes driving BVOC emissions in the Arctic. While boreal ecosystems have been widely studied, little attention has been paid to Arctic tundra environments. Here, we report terpenoid (isoprene, monoterpenes, and sesquiterpenes) ambient mixing ratios and emission rates from key dominant vegetation species at Toolik Field Station (TFS; 68°38′ N, 149°36′ W) in northern Alaska during two back-to-back field campaigns (summers of 2018 and 2019) covering the entire growing season. Isoprene ambient mixing ratios observed at TFS fell within the range of values reported in the Eurasian taiga (0–500 parts per trillion by volume – pptv), while monoterpene and sesquiterpene ambient mixing ratios were respectively close to and below the instrumental quantification limit (~ 2 pptv). Isoprene surface emission rates ranged from 0.2 to 2250 μgC m−2 h−1 (mean of 85 μgC m−2 h−1) and monoterpene emission rates remained, on average, below 1 μgC m−2 h−1 over the course of the study. We further quantified the temperature dependence of isoprene emissions from local vegetation, including Salix spp. (a known isoprene emitter), and compared the results to predictions from the Model of Emissions of Gases and Aerosols from Nature version 2.1 (MEGAN2.1). Our observations suggest a 180 %–215 % emission increase in response to a 3–4°C warming, and the MEGAN2.1 temperature algorithm exhibits a close fit with observations for enclosure temperatures in the 0–30°C range. The data presented here provide a baseline for investigating future changes in the BVOC emission potential of the under-studied Arctic tundra environment.

The genetic history of admixture across inner Eurasia.

The indigenous populations of inner Eurasia, a huge geographic region covering the central Eurasian steppe and the northern Eurasian taiga and tundra, harbor tremendous diversity in their genes, cultures and languages. In this study, we report novel genome-wide data for 763 individuals from Armenia, Georgia, Kazakhstan, Moldova, Mongolia, Russia, Tajikistan, Ukraine, and Uzbekistan. We furthermore report additional damage-reduced genome-wide data of two previously published individuals from the Eneolithic Botai culture in Kazakhstan (~5,400 BP). We find that present-day inner Eurasian populations are structured into three distinct admixture clines stretching between various western and eastern Eurasian ancestries, mirroring geography. The Botai and more recent ancient genomes from Siberia show a decrease in contribution from so-called “ancient North Eurasian” ancestry over time, detectable only in the northern-most “forest-tundra” cline. The intermediate “steppe-forest” cline descends from the Late Bronze Age steppe ancestries, while the “southern steppe” cline further to the South shows a strong West/South Asian influence. Ancient genomes suggest a northward spread of the southern steppe cline in Central Asia during the first millennium BC. Finally, the genetic structure of Caucasus populations highlights a role of the Caucasus Mountains as a barrier to gene flow and suggests a post-Neolithic gene flow into North Caucasus populations from the steppe.

High genetic diversity and distinct origin of recently fragmented Scots pine (Pinus sylvestris L.) populations along the Carpathians and the Pannonian Basin

Historical evolutionary events highly affect the modern-day genetic structure of natural populations. Scots pine (Pinus sylvestris L.), as a dominant tree species of the Eurasian taiga communities following the glacial cycles of the Pleistocene, has survived in small, scattered populations at the range limits of its south-eastern European distribution. In this study, we examined genetic relationships, genetic divergence and demographic history of peripheral populations from central-eastern Europe, the Carpathian Mountains and the Pannonian Basin. Four hundred twenty-one individuals from 20 populations were sampled and characterized with both nuclear and chloroplast simple sequence repeat (SSR) markers. Standard population genetic indices, the degree of genetic differentiation and spatial genetic structure were analysed. Our results revealed that peripheral Scots pine populations retained high genetic diversity despite the recently ongoing fragmentation and isolation of the persisting relict populations. Analysis of molecular variance (AMOVA) showed 7% among-population genetic differentiation, and there was no isolation by distance among the island-like occurrences. Genetic discontinuities with strong barriers (99–100% bootstrap support) were identified in the Carpathians. Based on both marker types, populations of the Western Carpathians were delimited from those inhabiting the Eastern Carpathians, and two main genetic lineages were traced that most probably originate from two main refugia. One refugium presumably existed in the region of the Eastern Alps with the Hungarian Plain, while the other was probably found in the Eastern Carpathians. These findings are supported by recent palynological records. The strongest genetic structure was revealed within the Romanian Carpathians on the basis of both marker types. With only some exceptions, no signs of recent bottlenecks or inbreeding were detected. However, Carpathian natural populations of Scots pine are highly fragmented and have a small census size, though they have not yet been affected by genetic erosion induced by isolation.

Heterogeneous response of circumboreal wildfire risk to climate change since the early 1900s

AbstractWe investigated changes in wildfire risk over the 1901−2002 (ad) period with an analysis of broad‐scale patterns of July monthly drought code (MDC) variability on 28 forested ecoregions of the North American and Eurasian continents. The MDC is an estimate of the net effect of changes in evapotranspiration and precipitation on cumulative moisture depletion in soils, and is well correlated with annual fire statistics across the circumboreal (explaining 25–61% of the variance in regional area burned). We used linear trend and regime shift analyses to investigate (multi‐) decadal changes in MDC and percentage area affected by drought, and kernel function for analysis of temporal changes in the occurrence rates of extreme drought years. Our analyses did not reveal widespread patterns of linear increases in dryness through time as a response to rising Northern Hemisphere land temperatures. Instead, we found heterogeneous patterns of drought severity changes that were inherent to the nonuniformly distributed impacts of climate change on dryness. Notably, significant trends toward increasing summer moisture in southeastern and southwestern boreal Canada were detected. The diminishing wildfire risk in these regions is coherent with widely reported decreases in area burned since about 1850, as reconstructed by dendrochronological dating of forest stands. Conversely, we found evidence for increasing percentage area affected by extreme droughts in Eurasia (+0.57% per decade;P<0.05) and occurrence rates of extreme drought years in Eurasian taiga (centered principally on the Okhotsk–Manchurian taiga,P=0.07). Although not statistically significant, temporal changes in occurrence rates are sufficiently important spatially to be paid further attention. The absence of a linear trend in MDC severity, in conjunction with the presence of an increase in the occurrence rate of extreme drought years, suggest that fire disturbance regimes in the Eurasian taiga could be shifting toward being increasingly pulse dependent.

Comparative phylogeography and demographic history of the wood lemming (Myopus schisticolor): implications for late Quaternary history of the taiga species in Eurasia

The association between demographic history, genealogy and geographical distribution of mitochondrial DNA cytochrome b haplotypes was studied in the wood lemming (Myopus schisticolor), a species that is closely associated with the boreal forest of the Eurasian taiga zone from Scandinavia to the Pacific coast. Except for a major phylogeographic discontinuity (0.9% nucleotide divergence) in southeastern Siberia, only shallow regional genetic structure was detected across northern Eurasia. Genetic signs of demographic expansions imply that successive range contractions and expansions on different spatial scales represented the primary historical events that shaped geographical patterns of genetic variation. Comparison of phylogeographic structure across a taxonomically diverse array of other species that are ecologically associated with the taiga forest revealed similar patterns and identified two general aspects. First, the major south-north phylogeographic discontinuity observed in five out of six species studied in southeastern Siberia and the Far East implies vicariant separation in two different refugial areas. The limited distribution range of the southeastern lineages provides no evidence of the importance of the putative southeastern refugial area for postglacial colonization of northern Eurasia by boreal forest species. Second, the lack of phylogeographic structure associated with significant reciprocal monophyly and genetic signatures of demographic expansion in all nine boreal forest animal species studied to date across most of northern Eurasia imply contraction of each species to a single refugial area during the late Pleistocene followed by range expansion on a continental scale. Similar phylogeographic patterns observed in this taxonomically diverse set of organisms with different life histories and dispersal potentials reflect the historical dynamics of their shared environment, the taiga forest in northern Eurasia.

Spring phenology in boreal Eurasia over a nearly century time scale

AbstractIt has been widely reported that tree leaves have tended to appear earlier in many regions of the northern hemisphere in the last few decades, reflecting climate warming. Satellite observations revealed an 8‐day advance in leaf appearance date between 1982 and 1991 in northern latitudes. In situ observations show that leaf appearance dates in Europe have advanced by an average of 6.3 days from 1959 to 1996. Modelling of leaf appearance on the basis of temperature also shows a marked advance in temperate and boreal regions from 1955 to 2002. However, before 1955, reported studies of phenological variations are restricted to local scale. Modelling, ground observations and satellite observations are here combined to analyse phenological variations in Eurasian taiga over nearly a century. The trend observed by remote sensing consists mainly in a shift at the end of the 1980s, reflecting a shift in winter and spring temperature. In western boreal Eurasia, a trend to earlier leaf appearance is evident since the mid‐1930s, although it is discontinuous. In contrast, the strong advance in leaf appearance detected over Central Siberia using satellite data in 1982–1991 is strengthened by late springs in 1983–1984; moreover, in this region the green‐up timing has displayed successive trends with opposite signs since 1920. Thus, such strong trend is not unusual if considered locally. However, the recent advance is unique in simultaneously affecting most of the Eurasian taiga, the leaf appearance dates after 1990 being the earliest in nearly a century in most of the area.

Isolation and cross-species amplification of microsatellite loci in the Siberian jay (Perisoreus infaustus).

Microsatellites are superior compared to other genetical markers for parentage determination, because they can be analysed from tiny and partially degraded DNA-samples extracted from e.g. hairs or bird feathers (ELLEGREN 1992). However, bird genomes contain relatively few microsatellite loci (LONGMIRE et al. 1999; PRIMMER et al. 1997b). It is therefore a tedious process to isolate a set of markers that is sufficient for conclusive parentage analyses. Here we report on nine microsatellite markers that are polymorphic in the Siberian jay (Perisoreus infaustus), a resident family dwelling species occurring throughout the Eurasian taiga (HELLE and LILLANDT 1997). The markers were found using two methods; (1) isolating new microsatellite sequences from a size-selected Siberian jay genomic library, and (2) exploring 64 heterologous microsatellite markers isolated in other mostly passerine species, and modifying primer sequences if necessary. This set of nine partly unpublished markers have previously been used for parentage testing on 298 juvenile Siberian jays from which feather or blood samples were collected during a long-term study in Finland 1976–1998. Methods for data analysis and parentage determinations were described in LIL-