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Article

The Bogs in a Forest–Steppe Region of Western Siberia: Plant Biomass and Net Primary Production (NPP)

1
Institute of Soil Science and Agrochemistry, Siberian Branch of the Russian Academy of Sciences (ISSA SB RAS), 8/2, Pr. Akademika Lavrentyeva, Novosibirsk 630090, Russia
2
Komarov Botanical Institute of the Russian Academy of Sciences, 2, Pr. Popova, Saint-Petersburg 197022, Russia
3
Tobolsk Complex Scientific Station of Ural Branch of the Russian Academy of Sciences, 15, Akademika Yu. Osipova, Tobolsk 626152, Russia
4
Tuvinian Institute for Exploration of Natural Resources, Siberian Branch of the Russian Academy of Sciences (TIENR SB RAS), 117A, Internacional, Kyzyl 667007, Russia
5
Science Partners, 42 Quai de Jemmapes, 75010 Paris, France
*
Authors to whom correspondence should be addressed.
Water 2023, 15(20), 3526; https://doi.org/10.3390/w15203526
Submission received: 30 August 2023 / Revised: 6 October 2023 / Accepted: 8 October 2023 / Published: 10 October 2023
(This article belongs to the Section Water and Climate Change)

Abstract

:
Hereby, we report the new experimental data of plant biomass and biological productivity (net primary production, NPP) of wetland/peatland plant communities of oligotrophic bogs located on the same latitude, but at a distance of 1300 km west-east in the forest–steppe region of Western Siberia. The data were collected by implementing direct in situ measurements based on a unique methodology developed by authors. The study revealed that the values of net primary production (NPP) are basically constrained by the live fraction of plant biomass (or phytomass). It also revealed that the dead fraction of plant biomass (mortmass), along with the live fraction of biomass (phytomass) and net primary production (NPP), all major components of the carbon cycle, differ significantly at the two study sites. The values of dead biomass (mortmass), live biomass (phytomass) and net primary production (NPP) were found at significantly higher values in bog ecosystems studied in western regions than in those of the eastern regions.

1. Introduction

The natural peatlands (the term “peatlands” refers to peat–accumulating wetlands) are well known as great pool of atmospheric carbon. Globally, peatlands contain some 600 ± 100 Gt of carbon in their peat deposits [1,2,3], i.e., 30% of the global soil carbon is found on only 3% of the global land [4,5]. This makes peatlands one of the most important long-term carbon stores in the terrestrial biosphere.
In peatlands, the peat accumulation and carbon sequestration result from the imbalance between gains (by annual increment of biomass via net primary production, or NPP, and photosynthesis), and losses (primarily by decay) of organic material. The accumulation rate differs strongly from place to place, depending on climate, hydrology and hydrochemistry. In general, peat accumulation increases from nutrient-rich to nutrient-poor, from polar to equatorial, and from continental to oceanic conditions [6]. The pool of organic matter, i.e., the live and dead biomass (or mortmass), and NPP represent a couple of major components of the carbon cycle in terrestrial ecosystems.
Quantitative assessments of the carbon cycle in natural peatlands remain far from being fully accomplished. The task is especially challenging for the peatlands in Western Siberia, with its large spatial coverage and very high ecosystem diversity [7,8,9].
In the forest–steppe region of Western Siberia, the peatlands currently exist at the southern climatic limit of their distribution, and the pine–dwarf shrub–Sphagnum raised bogs are one of the most common regional types. They occupy the lower landscape elements and topographical depressions, often of round shape, and they create boundary areas of large wetland massifs. The term “oligotrophic raised bog, or ryam” refers to peatland that exists in specific conditions of water and mineral supply; its “domed” shape of the land surface is formed at a certain stage of peat bog development [10,11,12,13]. In this region, the development of peat-accumulating wetlands is largely constrained by lack of moisture, but we still tend to consider them as part of boreal peatlands, which perform an important ecosystem function as a pool of atmospheric carbon [1]. Its state as a carbon sink is at risk of reversing dramatically at some “critical” point, as the result of abrupt climate change [14,15].
At present, in current climatic conditions, the areal coverage of peatlands is not large; it accounts for just 7 to 15% of the total area, but makes a significant contribution to the biological cycle at least at the regional scale [16]. The bogs (ryams) do not form very large bodies, but they rather represent small islands, so that they are also vulnerable to frequent land-surface fires. Therefore, the estimation of their biomass pool and biological productivity is a question of great scientific and practical importance in the current context of climate change and under anthropogenic pressure.
Productivity is the main feature of natural ecosystem functions. It can be described by three major parameters: live biomass (phytomass, g/m2), dead biomass (mortmass, g/m2) and net primary production (NPP, g/m2/yr), where NPP refers to the amount of organic matter produced by plant communities in a time unit (year) per area unit (m2) [17].
Overall, ongoing changes in climate and water balance lead to changes in productivity of wetland ecosystems, in which the production of the same plant species increases from north to south, as found out in Western Siberia [9,17,18] and in other regions around the world [19,20,21,22,23,24,25]. A certain change gradient of productivity values was found from west to east in the middle boreal (taiga) region in Western Siberia by our earlier studies [26]. The rate of exchange processes depends on ecosystem type, climate conditions and the latitude–longitude gradient [27]. So far, there were relatively few direct measurements of biomass storage and productivity of plant communities in wetland ecosystems of Western Siberia, especially in its forest–steppe region [28,29,30]. Also, there are a number of studies made in the south boreal (taiga) region [31,32,33,34,35,36] and in other regions of Western Siberia [9,37,38,39].
The aim of this study is to assess the values of biomass and productivity (net primary production (NPP) in oligotrophic (ryam-type) peat bogs in one bioclimatic forest–steppe region of Western Siberia using direct in situ measurements. The new data are going to bring more insights to the features of the carbon cycle in natural peatlands. Direct in situ measurements of carbon cycle components will provide a solid background for a range of modeling studies, where they are required as input data for training the models and verifying the model outputs. Overall, the study is going to have various implications for regional and global assessments of the impact of climate change on natural ecosystems and their potential for carbon sequestration.

2. Materials and Methods

Numerical assessment of biomass (phytomass) stock in the ryam ecosystems was made with reference to species composition of plant communities at different meso- and microtopographies, climatic conditions, and different geographical locations.
The study sites were located in the forest–steppe region, in the south of the West Siberian lowland, within the Kurgan and Novosibirsk administrative districts at a distance of 1300 km west–east from one another (Figure 1). Their location on the same latitude is going to provide a research framework that will us evaluate the spatial variability of carbon cycle components at different geographical locations. The studied ecosystems were the pine–dwarf shrub–Sphagnum bogs, co-called “ryam” communities.
The first (western) study site is “Kurganskoye” bog (KR) in the vicinity of Salomatovo village (at the border of the Chelyabinsk and Kurgan administrative districts), centered at 55°39′26.5″ N and 62°33′40.5″ E. This bog site is surrounded by eutrophic grass-dominated mires. The wood tier is formed with Pinus sylvestris in the ryam center with heights up to 16–18 m and a diameter of 13 ± 1.2 cm. On the periphery, the pine trunk diameter decreases to 12.2 ± 0.7 cm and the height decreases to 12 m. Crown density is 0.4. Total projective cover (pc) of the shrub tier does not exceed 30% and its height is about 40–50 cm. The dominant species are: Ledum palustre (10% pc), Chamaedaphne calyculata (10% pc) and Vaccinium vitis-idaea (10% pc). The bog is dry, so there is very little contribution of species common in ryam-type plant communities, such as Andromeda polifolia and Oxycoccus palustris. Rubus chamaemorus has a projective cover of 1%. Overall, the total projective cover of mosses does not exceed 10%. The mosses are in a very dry state and they often form small clumps at the bare land surface. The dominant species are Sphagnum (S. capillifolium—5% pc, S. angustifolium—5% pc), and green mosses: Pleurosium schreberi, Polytrichum strictum and Dicranum polysetum Sw. The depth of peat deposits is up to 4 m in the central part of the bog massif.
The second (eastern) study site is Nikolayevskiy ryam (NR) in the Ubinskiy area (Novosibirsk administrative district), centered at 55°09′ N and 79°02′ E. The bog is a very similar kind of pine–dwarf shrub–Sphagnum plant community, dominated by Pinus sylvestris, Eriophorum vaginatum, Chamaedaphne calyculata, Ledum palustre, Sphagnum angustifolium and S. magellanicum). The wood tier is formed with Pinus sylvestris, up to 12–14 m high and up to 10–16 cm in diameter. There is also Betula pubescens. Crown density is 0.1. The microtopography is represented by hummocks, which are 30–40 cm in height and are formed with mosses and shrubs; the hummocks create the highest areal coverage of the ryam and no more than 20% of the remaining area lies among them. The total projective cover of the shrubs is 60% and their heights are up to 40–50 cm. The dominant species are Ledum palustre (20–30% pc) and Chamaedaphne calyculata (20–30% pc). Among the shrubs, the most common is Vaccinium vitis-idaea (10% pc). The grasses (up to 10% pc) are represented by Rubus chamaemorus and Eriophorum vaginatum. The mosses have 90–100% pc, with the presence of Sphagnum fuscum—60% pc, S. capillifolium—30% pc, S. magellanicum Brid. and Sphagnum angustifolium—9% pc and Polytrichum strictum—1% pc. The depth of peat deposits is up to 4.25 m in the central part of the bog massif.
To assess the stocks of phytomass, mortmass and net primary production (NPP), the plant organic materials were collected during field campaigns. The measurements of above- and below-ground fractions of plant biomass were taken based on the methods developed by A.A. Titlyanova [40,41,42]. For our study, the samples were taken at 12 test plots of the size of 40 × 40 for above-ground fractions of plant organic matter, together with geobotanical descriptions. The Latin names are given according to S.K. Cherepanov [43]. A more even distribution of below-ground and “land-surface” (or moss) fractions was assured by taking small-size (10 × 10 cm) samples. In this way, 48 samples, each 10 × 10 cm, from the land surface to the depth of 30-cm, were taken at different positions of microtopography in the bog landscape. The sampling was conducted in the period of plant maximum growth, i.e., at the end of August. The plant organic matter was further divided into green biomass (phytomass) and mortmass in fresh (not dried) samples. The below-ground biomass was divided into a few fractions: tillering nodes, rhizomes, a large fraction of a size more than 2 mm, a medium-sized fraction of 2 to 0.5 mm, and a fraction of plant materials sized less than 0.5 mm. All fractions of plant organic matter were dried to an air-dry state at a temperature of 60 °C and weighed. Moss core samples were taken near each test plot with simultaneous measuring of linear growth in one-species clumps. Moss growing on elevated topographical elements, where mosses grow straight up as dense turf, was assessed with three–four ‘brush wire’ marks [44]. At the lower topographical elements, the linear growth was measured with ‘brush wire’ and ‘individual tags’ methods [26,45]. As a whole, 80 samples of different kinds were taken from all the studied test plots, and the linear growth was measured 190 times. The organic materials of mosses were divided into several fractions such as apical tops, the upper 3 cm of stems and photosynthetic (or live) parts of Sphagnum mosses; then, the NPP was counted as annual linear growth (mm) multiplied by the weight of 1 mm moss stems taken from 1 dm2 plots in grams. The stocks of all components (and fractions) of plant organic matter were then recalculated in grams per square meter.

3. Results

The biomass in bog ecosystems is formed with pine, evergreen heather shrubs and grasses, which consist of live biomass stocks (photosynthetic leaves of different age and shoots) and mortmass (deadwood, standing dead residues and litter of vascular plants). After the life cycle, the organic matter of Sphagnum mosses is exposed to decomposition and further contributes to peat deposits.

3.1. Dead Biomass (Mortmass)

The dead biomass (mortmass) of different fractions is presented in Table 1. The total mortmass (of trees, shrubs and mosses) in the uppermost 30-cm depth accounts for 7059 ± 1881, as found in the bog ecosystems of the eastern (NR) study site, and up to 20,077 ± 3666 g/m2 as found in the west of the forest–steppe (study site KR).
In the structure of mortmass, the fraction of Sphagnum mosses makes the most notable contribution at both study sites. The contribution of litter was found to be 2.5 times less in the ecosystems of eastern bogs (NR). The high level of the water table and good aeration of the active layer led to rapid decomposition of the roots of trees and shrubs, which turned into non-identified remains of vascular plants.
The wooden fraction of mortmass (dead roots of pine trees, needles and branches) makes a significant contribution to the total mortmass in the west (KR), but this fraction accounts for zero in the east. In the bog sites of KR, the upper 10-cm depth consisted of forest litter, also with some wooden residues penetrating to deep layers in a soil profile. The layers of peat with inclusions of wooden remains can be found quite often in the peat deposits at about a 20-cm depth. Dry conditions in the western bogs suggest slow rates of decomposition, so that the dead roots of pine trees and shrubs make a significant contribution to the mortmass: 314 ± 203 and 516 ± 336 g/m2, respectively. Those kinds of residues are well distinguished in the mortmass despite high heterogeneity in distribution. The dead fraction of Sphagnum mosses in the west (KR) is 2 times higher than that in the east (NR). Furthermore, in the uppermost 30-cm depth, the organic matter of mosses was found at minor decomposition rates in the eastern (NR) ecosystems, with the majority of moss residues retaining the structure of ‘tow’, whereas the organic matter was found strongly decomposed and compacted to peat deposits in the western (KR) ecosystems.

3.2. Live Biomass

Overall, the study revealed large differences in live biomass (phytomass) values between the two study sites: 8964 ± 195 g/m2 at the western study site (KR), but 2.4 times less (3701 ± 281 g/m2) at the eastern study site (NR); all values included the biomass of pine trees (the data are presented in Table 2). At the same time, the live biomass accounts for 940 ± 291 and 2297 ± 220 g/m2 for the KR and NR study sites, respectively, when the woody layer is excluded. At the western study site (KR), the live biomass of pine trees accounted for 8024 ± 164 g/m2 (that is, 89.5% of the total live biomass); among these values, 6550 ± 782 g/m2 is contributed by above-ground and 1474 ± 142 g/m2 is contributed by below-ground wooden fractions (see Table 2 for details). At the eastern study site (NR), the live biomass of pine trees accounted for 1404 ± 35 g/m2 (that is, 37.9% of the total live biomass), among them 995 ± 141 g/m2 of above-ground and 409 ± 95 g/m2 of below-ground wooden fractions. That is 5.7 times less than the value found at the western study site (KR). Within the wooden fraction, the ratio of above- to below-ground fractions of live biomass is 4:1 found at the KR study site, and 2:1 at the NR study site. The phytomass of mosses was found to be much (i.e., 3 times) higher at the NR, but with almost the same phytomass of grasses in its above-ground fraction. The above-ground fraction of shrubs is 3.9 times higher at the NR site than at the KR study site.
In both study sites, three kinds of heather shrubs dominate in land cover: Ledum palustre, Chamaedaphne calyculata and Vaccinium vitis-idaea. In addition, there is some minor contribution of Andromeda polifolia and Oxycoccus palustris in the land cover of the western ryam, while Andromeda polifolia contributes up to 42 g/m2 and Oxycoccus palustris 8 g/m2 in the ecosystem of the eastern ryam. The stocks of Chamaedaphne calyculata can increase by 7 times, to contribute 216.8 g/m2. The maximum biomass refers to Ledum palustre, at 222.6 g/m2, while Vaccinium vitis-idaea has the value of 8.6 g/m2. The biomass of shrubs was found to be much lower in western bogs: Chamaedaphne calyculata—39 g/m2, Ledum palustre—31.3 g/m2 and Vaccinium vitis-idaea—41 g/m2 (Table 3).
The live biomass at the KR increases twice from the center to the periphery of the bog ecosystem, from 111 to 217 g/m2. The same shrubs grow better under more humid conditions. Myrtle domination increases by 4 times, Ledum by 2 times and only the less competitive shrubs of lingonberry lose their dominating position and decrease by 2.5 times.
Perennial parts contribute more than half of the live biomass at the western (KR) study site, whereas the same contribution was made by photosynthetic (green) organs at the eastern (NR) study site.
The above-ground fraction of live biomass largely depends on the structure of the ecosystem plant community. In the direction from west to east, the values of wooden biomass and mortmass decrease, while the values of shrub photosynthetic phytomass increase. In the live biomass, there is a constant distribution of plant groups in dependence on their ratio in the plant community structure; for instance, it is observed for evergreen shrubs in the grass–shrub tier. In the western ryams, the values of live phytomass of shrubs ranged from 110 g/m2 to 220 g/m2, while the values go up to 460 g/m2 in the eastern ryams. The contribution of grasses is minor in all studied ecosystems and accounts for only 1–3%.
The moss cover was considered as a separate tier that has its own structure, density and annual linear growth; the combination of these factors characterizes moss production. The features of Sphagnum moss cover at study sites are presented in Figure 2.
The mosses at the KR study site have a dense core structure (Sphagnum fuscum) and a density of up to 480–650 pieces per 1 dm2. We found their linear growth was not high (3.5–6.2 mm) and their production is 0.4–0.9 g/dm2/yr (Figure 2). The density of Sphagnum fuscum at the eastern (NR) bog was in a range of 250–600 pieces per 1 dm2, and its linear growth was higher than that at the western (KR) bog (26–28 mm/yr). Such a combination leads to a high production of 1.4–1.9 g/dm2/yr.
At the western (KR) site, the density of Sphagnum magellanicum, S. angustifolium, S. capillifolium accounts for 210 to 440 pieces per 1 dm2 and the linear growth of Sphagnum magellanicum is 5.5–10.5 mm/yr, that of S. angustifolium is 11.3–19 mm and that of S. capillifolium 12.1–20 mm/yr. At the eastern (NR) bog site, the density accounts for 140 to 380 pieces per 1 dm2 and the linear growth of Sphagnum magellanicum is 22–27 mm/yr, that of S. angustifolium is 37–54 mm/yr and that of S. capillifolium is about 29 mm/yr. Production of mosses ranges from 0.7 to 1.8 g/dm2/yr. Mosses of S. riparium and S. fallax have the highest production; Sphagnum riparium moss has the highest production (up to 3.5 g/dm2/yr) and has the highest linear growth among all the mosses at the eastern ryam (35 mm). Moss of S. fallax gives a production of 1.6–1.8 g/dm2/yr and its linear growth is 18.7 mm/yr. At the eastern bog sites, S. fallax grows up to 46–52 mm/yr, with a core density of 180–300 pieces per 1 dm2. Its production amounts 3.2–3.6 g/dm2/yr. The maximum values of linear growth are shown by Sphagnum riparium (160–180 mm); its production amounts to 8.6 g/dm2/yr.
Thus, the study revealed both the stable parameters that constrain the growth of each kind of Sphagnum moss (the density and relative value of linear growth) and variable parameters, such as the geographical location of the study site, that also constrain linear growth and production. At the western bog site, lower production and linear growth were observed in a very sparse moss projective cover. And at the western bog site, such a combination makes Sphagnum moss play a less edaphic role compared to that at the eastern (NR) ryam.
Overall, we suggest the most important fraction of the plant biomass affecting bog ecosystem functioning is the live phytomass in all plant communities (ecosystems). The below-ground fraction of biomass contributes more than half the total. There is also significant contribution made by Sphagnum mosses, which is especially notable in the humid conditions of the eastern ryam.

3.3. Net Primary Production (NPP)

The study revealed the Net Primary Production (NPP) is 745 ± 152 g/m2/yr in the bog ecosystems of the western study site (KR) and 572 ± 111 g/m2/yr in the bog ecosystems of the eastern study site (NR), when all fractions of NPP are included (Table 4). The structure of NPP is also presented in Figure 3.
Within the total NPP, 20% and 57% are contributed by above-ground fractions (ANP) in the bog ecosystems at the KR and NR study sites, respectively. We also found the highest NPP is contributed by the below-ground component of the wood tier (BNP of pine trees) in the bog ecosystems at KR (56% of the NPP); but there was no major component eventually found in bog ecosystems at NR. In the western bogs (KR study site), 12% is contributed by the below-ground fraction of shrubs and about 7% of NPP is contributed by Sphagnum mosses. Among absolute values, both the above- and below-ground fractions of shrubs display higher values in the eastern bogs (NR study site) compared to the western bogs. The above-ground fraction of grasses corresponds to a minor contribution at both study sites. Also, we note the above-ground fraction of pine trees at almost the same values among the studied ecosystems, regardless of geographical location. Overall, the total ANP was found to have higher values in the eastern bog ecosystems than in the western bog ecosystems, but for the BNP it is vice versa.
When we exclude the wooden tier, the values of NPP (which account for both the above- and below-ground fractions, NPP = ANP + BNP) are 243 and 467 g/m2/yr of green biomass, for the western (KR) and the eastern (NR) bog ecosystems, respectively. Furthermore, the study revealed that the ecosystems of the eastern study site (NR) produce more biomass per year (NPP), in both the above- and below-ground sectors. The total ANP in the eastern bogs was found to be 79% higher than that in the west, and the total BNP was found to be 33% higher.

4. Discussion

Despite relatively the same structure of pine–shrub–Sphagnum oligotrophic bogs located at the same latitude but at a great distance from each other (1300 km west–east), there are certain differences in the values of live and dead biomass and net primary production at two study sites in the forest–steppe region of Western Siberia.
Overall, we suspect the main drivers of biomass and net primary production (NPP) in the same kind of oligotrophic bogs are some (even minor) differences in the soil mineral supply, along with differences in climatic conditions, that manifest first of all in different developments of the wooden tier. The better-developed wooden tier of Pinus sylvestris (with higher trees, larger litter stock and below-ground biomass) was found in the western variant of the bog ecosystems. In general, the wood tier could be at different stages of development in oligotrophic pine–shrub–Sphagnum bog ecosystems [7,8], which in turn is reflected in the characteristics of natural cycles [9]. The shrub tier is represented by only three species: Ledum palustre, Chamaedaphne calyculata and Vaccinium vitis-idaea. The grasses make a minor contribution in both ecosystems, in terms of biomass stock and NPP. Overall, the species diversity is limited to 7–10 varieties in the western variant of the bogs, whereas it is up to 15–18 species in the eastern variant of the bogs, mainly due to the diversity of shrubs.
In this study, the values of live biomass were in a range of from 3701 ± 281 g/m2 found in the eastern bogs to 8964 ± 195 g/m2 found in the western bogs; the western values exceed the eastern when we consider all biomass components, including the wooden tier. In the case that we exclude the wooden tier, in contrast, the eastern values exceed the western values, at 2297 ± 220 and 940 ± 291 g/m2, respectively.
The total mortmass is 3 times lower and the litter 4 times lower in the eastern bogs than in their western versions, which also implies a higher rate of mineralization in the upper peat layers in the east.
The below-ground fraction of biomass was found to create about 70% of the total NPP, with a great contribution of shrub roots. Such ratios are specific to pine–shrub–Sphagnum communities in other Western Siberian regions [26]. An average below-ground production 2–3 times larger than above-ground production was also found by N.I. Bazilevich [17].
When we consider all fractions of net primary production (NPP), including the wooden tier, it accounts for 745 ± 152 g/m2/yr in the western bogs, whereas it accounts for 572 ± 111 g/m2/yr in the eastern bogs—the western exceed the eastern. In contrast, when we exclude the wooden tier from our assessments, the NPP accounts for 243 ± 57 g/m2/yr in the western bogs and 467 ± 59 g/m2/yr in the eastern bogs—the eastern exceed the western. In previous studies across bog-type ecosystems, the NPP stays in a range of 560–800 g/m2/yr [39,46]. In the bogs of Southern Sweden, the NPP accounts for 800 g/m2/yr, with a contribution of the below-ground fraction of more than 70% [47]. As for the bogs in boreal Western Siberia, the contribution of the below-ground fraction accounted for 60% on average [48]. Overall, the values of net primary production (NPP) in bogs developed under oligotrophic conditions are comparable with those of zonal forest ecosystems [9,17].
The results of our study can be compared to those of biomass stock and net primary production (NPP) obtained for bog ecosystems in Canada [19], in Sweden [49], in Finland [50], and is also confirmed by our earlier studies in Western Siberia [18]. According to these reports, the net primary production in oligotrophic bogs remains in a wide range of from 350 to 1940 g/m2/yr, and it tends to increase from north to south. In Finland, the NPP was found to be in a range of from 150 to 336 g/m2/yr in grass-dominated peatlands [51], where 25% was contributed by above-ground and 75% was contributed by below-ground fractions (the Carex roots were found to produce up to 870 g/m2/yr). According to [21], mesotrophic bogs are the most productive in the middle boreal region (890 g/m2/yr), where an equal share of 40% is contributed by the grass-dominated below-ground fraction and the fraction of mosses, and the remaining 20% is contributed by the above-ground fraction of grasses and shrubs.
Under current climatic conditions in the forest–steppe region, in its western part, the moss cover is getting sparse and shrub cover is reducing the area. At the same time, climatic conditions greatly favour the development of the wood tier that in turn increases the NPP of ecosystems. Due to the low projective cover of mosses, their contribution to the carbon cycle (both the live biomass/phytomass and NPP) was found to be about 3 times less in western bogs than in eastern bogs. Climatic conditions at the eastern study sites stimulate the growth of shrubs, so that their biomass increases by 2.5 times compared with western study sites, and those of below-ground parts increases twice. The trees grow with difficulty because of overgrowing shrub and moss tiers in the eastern part of the forest–steppe region.
The distance of 1300 km from west to east (along 17° E) led to drastic changes in production processes: (i) the biomass decreased to a large extent (mainly via the wood tier), (ii) the net primary production (NPP) decreased by 23%; and (iii) the biomass of mosses and the below-ground fraction of shrubs increased, in the same direction.

5. Conclusions

In the pine–dwarf shrub–Sphagnum bog/ryam ecosystems in Western Siberia, the values of biomass and net primary production (NPP) vary significantly at different geographical locations at the same latitude. Due to the increase in climate severity (continentality) from west to east, the height, diameter of tree trunks, and the wooden (pine tree) fractions of above-ground and below-ground biomass decrease. Among all studied ecosystems, the above-ground wooden (pine tree) biomass accounts for 6550 ± 782 and 995 ± 141 g/m2 in the western and in the eastern bogs, respectively. The below-ground biomass of pine trees accounts for 1474 ± 142 and 409 ± 95 g/m2 in the western and in the eastern bogs, respectively. In the same direction, the contribution of shrubs increases from 747 ± 79 to 1846 ± 367 g/m2, and the contribution of mosses increases from 135 ± 17 to 419 ± 69 g/m2. We suspect this change is also driven by the rise of water tables in peat deposits at the eastern study site in the forest–steppe region of Western Siberia.
In the west of the forest–steppe region, with heterogeneous and often sporadic moss cover, the study revealed somewhat low linear growth and production due to strong drainage of peat deposits. It also caused high values of litter biomass (461 ± 194 g/m2), which is 2.5 times that of the eastern part of the forest–steppe region (175 ± 32 g/m2). In the east of the forest steppe, a high water table observed in peat deposits leads to higher linear growth and higher production of Sphagnum mosses. The highest ratio of dead biomass (mortmass) compared to live biomass was observed in the western part of the forest–steppe region, where its absolute values account for 20,077 ± 3666 g/m2, whereas it accounts for 7059 ± 1881 g/m2 in the eastern part of the region.
Overall, across the forest–steppe region in Western Siberia, a certain change of climatic conditions eastward towards greater severity is leading to an increase in the water table in peat deposits, following by a decrease in the wooden fraction of biomass. In turn, these conditions lead to an increase in the above-ground fraction of biomass of dwarf shrubs and mosses and to a decrease in the below-ground biomass of roots. In the same direction, the contribution of above-ground net primary production (NPP) increases from 150 to 324 g/m2/yr, and below-ground net primary production (NPP) decreases from 595 to 248 g/m2/yr.

Author Contributions

Conceptualization, N.P.K., T.G.I. and N.G.K.; methodology, N.P.K. and N.P.M.-T.; software, N.P.K.; formal analysis, E.K.V., N.P.K., N.G.K. and S.S.K.; investigation, N.P.K. and A.M.P.; writing—original draft preparation, N.P.K.; writing—review and editing, N.P.K. and A.M.P.; visualization, N.P.K. and N.G.K. All authors have read and agreed to the published version of the manuscript.

Funding

The work of Natalia P. Kosykh, Natalia G. Koronatova, Nina P. Mironycheva-Tokareva and Evgenia K. Vishnyakova was carried out according to the state order of the Institute of Soil Science and Agrochemistry, Siberian Branch of the Russian Academy of Sciences (ISSA SB RAS), with the financial support of the Ministry of Science and Higher Education of the Russian Federation. The work of Tatiana G. Ivchenko was carried out within the framework of the planned topics: of the Komarov Botanical Institute of the Russian Academy of Sciences “Vegetation of European Russia and Northern Asia: diversity, dynamics, principles of organization” (№ 121032500047-1); and of the Tobolsk Complex Scientific Station of Ural Branch of the Russian Academy of Sciences “Biodiversity of wetland ecosystems in the south of Western Siberia” (№ AAAA-A19-119011190112-5).

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Gorham, E. Northern peatlands: Role in carbon cycle and probable responses to climatic warming. Ecol. Appl. 1991, 1, 182–195. [Google Scholar] [CrossRef] [PubMed]
  2. Vompersky, S.E.; Ivanova, A.I.; Tsyganova, O.P.; Valiaeva, N.A.; Glukhova, T.V.; Dubinin, F.I.; Markelova, L.G. Wet soils and mires in Russia and their carbon pool. Pochvovedenie 1994, 12, 17–25. (In Russian) [Google Scholar]
  3. Yu, Z.; Joos, F.; Bauska, T.K.; Stocker, B.D.; Fischer, H.; Loisel, J.; Brovkin, V.; Hugelius, G.; Nehrbass-Ahles, C.; Kleinen, T.; et al. No support for carbon storage of >1000 GtC in northern peatlands. Earth arXiv 2019, reprints. [Google Scholar] [CrossRef]
  4. Scharlemann, J.P.W.; Tanner, E.V.J.; Hiederer, R.; Kapos, V. Global soil carbon: Understanding and managing the largest terrestrial carbon pool. Carbon Manag. 2014, 5, 81–91. [Google Scholar] [CrossRef]
  5. Kirpotin, S.N.; Antoshkina, O.A.; Berezin, A.E.; Elshehawi, S.; Feurdean, A.; Lapshina, E.D.; Pokrovsky, O.S.; Peregon, A.; Semenova, N.M.; Tanneberger, F.; et al. Great Vasyugan Mire: How the World’s largest peatland helps addressing the World’s largest problems. Ambio 2021, 50, 2038–2049. [Google Scholar] [CrossRef]
  6. Botch, M.S.; Kobak, K.I.; Vinson, T.S.; Kolchugina, T.P. Carbon pools and accumulation in peatlands of the former Soviet Union. Global Biogeochem. Cycles 1995, 9, 37–46. [Google Scholar] [CrossRef]
  7. Lapshina, E. Spatial structure of the vegetation cover in the Vasyugan Mire. In Mires from Siberia to Tierra del Fuego; Steiner, G.M., Ed.; Stapfia; OÖ Landes-Kultur GmbH: Linz, Austria, 2005; Volume 85, pp. 296–304. [Google Scholar]
  8. Lapshina, E.D.; Pologova, N.N.; Muldiyarov, Y.Y. Mires of watershed plains in the south of the boreal region in Western Siberia. Krylovia 2000, 2, 38–43. (In Russian) [Google Scholar]
  9. Peregon, A.; Maksyutov, S.; Kosykh, N.; Mironysheva-Tokareva, N. Map based inventory of the wetland biomass and NPP in western Siberia. J. Geophys. Res. 2008, 113, G01007. [Google Scholar] [CrossRef]
  10. Bronzov, A.Y. Raised bogs of the Narymski Krai (Vasyugan Basin). Proc. Peat Inst. 1930, 3, 1–99. (In Russian) [Google Scholar]
  11. Romanova, E.T. Bog of Western Siberia; Gidrometeoisdat: Leningrad, Russia, 1976; pp. 25–33. (In Russian) [Google Scholar]
  12. Romanova, E.A. Mire Vegetation. The Land-Cover of the West Siberian Plain; Nauka: Novosibirsk, Russia, 1985; pp. 138–161. (In Russian) [Google Scholar]
  13. Liss, O.L.; Abramova, L.I.; Avertov, N.A.; Berezina, N.A.; Inisheva, L.I.; Kournikova, T.V.; Sluka, Z.A.; Tolpysheva, T.Y.; Shvedchikova, N.K. Bog Systems of Western Siberia and Their Environmental Significance; Grif and K°.: Tula, Russia, 2001; 584p. [Google Scholar]
  14. Leifeld, J.; Wüst-Galley, C.; Page, S. Intact and managed peatland soils as a source and sink of GHGs from 1850 to 2100. Nat. Clim. Chang. 2019, 9, 945–947. [Google Scholar] [CrossRef]
  15. Mikhalchuk, A.; Kharanzhevskaya, Y.; Burnashova, E.; Nekhoda, E.; Gammerschmidt, I.; Akerman, E.; Kirpotin, S.; Nikitkin, V.; Khovalyg, A.; Vorobyev, S. Soil Water Regime, Air Temperature, and Precipitation as the Main Drivers of the Future Greenhouse Gas Emissions from West Siberian Peatlands. Water 2023, 15, 3056. [Google Scholar] [CrossRef]
  16. Valutsky, V.I. Vegetation of forest-steppe ryams in East Baraba. Turczaninowia 2011, 14, 109–119. [Google Scholar]
  17. Bazilevich, N.I. Biological Productivity of Ecosystems of Northern Eurasia; Nauka: Moscow, Russia, 1993; 293p. (In Russian) [Google Scholar]
  18. Naumov, A.V.; Kosykh, N.P.; Mironycheva-Tokareva, N.P. Network environment analysis of a model of carbon flows in a peat bog and fen. Mires and Peat 2020, 26, 1–18. [Google Scholar]
  19. Reader, R.J.; Stewart, J.M. The relationship between net primary production and accumulation for a peatland in southern-eastern Manitoba. Ecology 1972, 53, 1024–1037. [Google Scholar] [CrossRef]
  20. Vitt, D.H. Growth and production dynamics of boreal mosses over climatic, chemical and topographic gradients. Bot. J. Linn. Soc. 1990, 104, 35–59. [Google Scholar] [CrossRef]
  21. Moore, T.R.; Bubier, J.L.; Frolking, S.E.; Lafleur, P.M.; Roulet, N.T. Plant biomass and production and CO2 exchange in an ombrotrophic bog. J. Ecol. 2002, 90, 25–36. [Google Scholar] [CrossRef]
  22. Thormann, M.N.; Bayley, S.E. Aboveground net primary production along a bog–fen–marsh gradient in southern boreal Alberta, Canada. Ecoscience 1997, 4, 374–384. [Google Scholar] [CrossRef]
  23. Szumigalski, A.R.; Bayley, S.E. Net aboveground primary production along a peatland gradient in central Alberta in relation to environmental factors. Ecoscience 1997, 4, 385–393. [Google Scholar] [CrossRef]
  24. Campbell, C.; Vitt, D.H.; Halsey, L.A.; Campbell, I.D.; Thormann, M.N.; Bayley, S.E. Net Primary Production and Standing Biomass in Northern Continental Wetlands; Canadian Forestry Service Information Report NOR-X-369; Canadian Forestry Service: Edmonton, AB, Canada, 2000. [Google Scholar]
  25. Backéus, I. Production and depth distribution of fine roots in a boreal open bog. Ann. Bot. Fenn. 1990, 27, 261–265. [Google Scholar]
  26. Kosykh, N.P.; Koronatova, N.G.; Naumova, N.B.; Titlyanova, A.A. Above- and below-ground phytomass and net primary production in boreal mire ecosystems of Western Siberia. Wetl. Ecol. Manag. 2008, 16, 139–153. [Google Scholar] [CrossRef]
  27. Bazilevich, N.I.; Titlyanova, A.A. Biotic Cycle on Five Continents; SB RAS: Novosibirsk, Russia, 2008; 380p. (In Russian) [Google Scholar]
  28. Vagina, T.A.; Shatochina, N.G. Productivity of plant communities and the influence of soil and weather conditions. In Structure, Functioning and Evolution of the System of Biogecenoses of Baraba; Nauka SB: Novosibirsk, Russia, 1976; pp. 217–359. (In Russian) [Google Scholar]
  29. Naumov, A.V.; Kosykh, N.P.; Parshina, E.K.; Artymuk, S.Y. Raised bogs of the forest-steppe zone, their condition and monitoring. Sib. J. Ecol. 2009, 2, 251–259. [Google Scholar]
  30. Kosykh, N.P. Biological productivity of mire in the forest-steppe zone. Bull. TGPU 2009, 3, 87–91. [Google Scholar]
  31. Bazilevich, N.I. Productivity and biological circulation in the moss swamps of Southern Vasyugan. Plant Resour. 1967, 3, 567–589. (In Russian) [Google Scholar]
  32. Valutskiy, V.I.; Khramov, A.A. Structure and net primary production of ryams in the south-eastern Vasyugan region. In Theory and Practice of Forest Swamp Management and Hydroforestry Reclamation; ILiD SO AN USSR: Krasnoyarsk, Russia, 1976; pp. 59–82. (In Russian) [Google Scholar]
  33. Efremov, S.P.; Efremova, T.T.; Bleuten, V. Biological productivity and carbon pool of phytomass in forested wetlands in Western Siberia. Sib. J. Ecol. 2005, 1, 29–44. (In Russian) [Google Scholar]
  34. Golovatskaya, E.A. Biological productivity of oligotrophic and eutrophic mires in the Southern Taiga of Western Siberia. J. Sib. Fed. Uni. Biol. 2009, 2, 38–53. (In Russian) [Google Scholar]
  35. Golovatskaya, E.A. Biomass and productivity of the wooden tier in pine-dwarf shrubs-Sphagnum bogs in south taiga of Western Siberia. Forestry 2017, 2, 102–110. (In Russian) [Google Scholar]
  36. Inisheva, L.I.; Golovatskaya, E.A. Elements of the carbon balance of oligotrophic bogs at the edges of the Vasyugan mires. Ecology 2002, 4, 242–249. (In Russian) [Google Scholar]
  37. Piyavchenko, N.I. Biological productivity and flow of matter in paludified forests in Western Siberia. Forestry 1967, 3, 32–43. (In Russian) [Google Scholar]
  38. Piyavchenko, N.I. On the productivity of wetlands in Western Siberia. Plant Resour. 1967, III, 523–533. (In Russian) [Google Scholar]
  39. Titlyanova, A.A. Net primary production of grasslands and wetland ecosystems. Sib. J. Ecol. 2007, 5, 763–770. (In Russian) [Google Scholar]
  40. Titlyanova, A.A.; Mironycheva-Tokareva, N.P. Vegetation succession and biological turnover on coal mining spoil. J. Veget. Sci. 1990, 14, 643–652. [Google Scholar] [CrossRef]
  41. Titlyanova, A.A.; Kosykh, N.P.; Mironycheva-Tokareva, N.P. Dynamics of below-ground plants organs in grasslands. In Root Demographics and Their Efficiencies in Sustainable Agriculture, Grasslands and Forest Ecosystems; Kluwer Acad. Publishers: Dordrecht, The Netherlands, 1998; pp. 247–265. [Google Scholar]
  42. Kosykh, N.P.; Mironycheva-Tokareva, N.P.; Peregon, A.M.; Parshina, E.K. Net primary production in peatlands of middle taiga region in western Siberia. Russ. J. Ecol. 2008, 39, 466–474. [Google Scholar] [CrossRef]
  43. Cherepanov, S.K. Vascular Plants of Russia and Neighboring Countries; SPb: St. Petersburg, Russia, 1995; 992p. (In Russian) [Google Scholar]
  44. Bengtsson, F.; Granath, G.; Rydin, H. Photosynthesis, growth, and decay traits in Sphagnum—A multispecies comparison. Ecol. Evol. 2016, 6, 3325–3341. [Google Scholar] [CrossRef] [PubMed]
  45. Kosykh, N.P.; Koronatova, N.G.; Granath, G. Effect of Temperature and Precipitation on Linear Increment of Sphagnum fuscum and S. magellanicum in Western Siberia. Russ. J. Ecol. 2017, 48, 173–181. [Google Scholar]
  46. Bazilevich, N.I.; Grebenshchikov, O.S.; Tishkov, A.A. Geographical Patterns of Structure and Functioning of Ecosystems; Nauka: Moscow, Russia, 1986; 297p. (In Russian) [Google Scholar]
  47. Wallen, B. Above and below-ground dry mass of the three main vascular plants on hummocks on a subarctic peat bog. Oikos 1986, 46, 51–56. [Google Scholar] [CrossRef]
  48. Kopoteva, T.A.; Kosykh, N.P. Comparative characteristics of the structure of phytomass and productivity of mesotrophic shrub-Sphagnum bogs in the boreal region. Sib. J. Ecol. 2011, 2, 301–307. [Google Scholar]
  49. Wallen, B. Methods for studing below-ground production in mire ecosystems. Suo 1992, 43, 155–162. [Google Scholar]
  50. Murphy, M.T.; McKinley, A.; Moore, T.R. Variation in above-and below-ground vascular plant biomass and water table on a temperate ombrotrophic peatland. Botany 2009, 87, 845–853. [Google Scholar] [CrossRef]
  51. Saarinen, T. Vascular Plants as Input of Carbon in Boreal Sedge Fens: Control of Production and Partitioning of Biomass; Publications in Botany, University of Helsinki: Yliopistopaino, Finland, 1999; 66p. [Google Scholar]
Figure 1. Location of study sites (at the Google maps view, available at https://www.google.com/maps/, accessed 5 October 2023), where KR is the western study site—“Kurganskoye bog” (55°39′26.5″ N; 62°33′40.5″ E), and NR is the eastern study site—“Nikolaevskiy ryam” (55°09’ N; 79°02’ E), both located in a forest steppe region of Western Siberia.
Figure 1. Location of study sites (at the Google maps view, available at https://www.google.com/maps/, accessed 5 October 2023), where KR is the western study site—“Kurganskoye bog” (55°39′26.5″ N; 62°33′40.5″ E), and NR is the eastern study site—“Nikolaevskiy ryam” (55°09’ N; 79°02’ E), both located in a forest steppe region of Western Siberia.
Water 15 03526 g001
Figure 2. Sphagnum moss quantity characteristics studied at two bog sites. 1—western study site (KR), 2—eastern study site (NR). S. fus.—Sphagnum fuscum, S. mag.—S. magellanicum, S. ang.—S. angustifolium, S. cap.—S. capillifolium, S. fal.—S. fallax, S. rip.—S. riparium, S. pap.—S.papillosum. The ranges on tops of bar plots correspond to standard deviation (SD).
Figure 2. Sphagnum moss quantity characteristics studied at two bog sites. 1—western study site (KR), 2—eastern study site (NR). S. fus.—Sphagnum fuscum, S. mag.—S. magellanicum, S. ang.—S. angustifolium, S. cap.—S. capillifolium, S. fal.—S. fallax, S. rip.—S. riparium, S. pap.—S.papillosum. The ranges on tops of bar plots correspond to standard deviation (SD).
Water 15 03526 g002
Figure 3. Net Primary Production (NPP) in bog ecosystems investigated at two study sites, western (KR) and eastern (NR). Note: ANP—above-ground fraction of NPP, BNP—below-ground fraction of NPP. The ranges on the bar plots correspond to standard deviation (SD).
Figure 3. Net Primary Production (NPP) in bog ecosystems investigated at two study sites, western (KR) and eastern (NR). Note: ANP—above-ground fraction of NPP, BNP—below-ground fraction of NPP. The ranges on the bar plots correspond to standard deviation (SD).
Water 15 03526 g003
Table 1. Structure of mortmass in the uppermost 30-cm depth of peat deposits (g/m2) as measured at western (KR) and eastern (NR) study sites.
Table 1. Structure of mortmass in the uppermost 30-cm depth of peat deposits (g/m2) as measured at western (KR) and eastern (NR) study sites.
Fractions of Dead Biomass (Mortmass)KRNR
Litter and above-ground residues461 ± 168187 ± 29
Wooden residues (pine trees)7584 ± 23760
Vascular plants660 ± 272856 ± 468
Sphagnum mosses11,373 ± 31566016 ± 1391
Total20,077 ± 36667059 ± 1881
Table 2. Different fractions of live biomass (phytomass) in bog/ryam ecosystems (g/m2) as measured at western (KR) and eastern (NR) study sites.
Table 2. Different fractions of live biomass (phytomass) in bog/ryam ecosystems (g/m2) as measured at western (KR) and eastern (NR) study sites.
Fractions of Live BiomassKRNR
Pine above-ground phytomass6550 ± 782995 ± 141
Pine roots (0–30 cm)1474 ± 142409 ± 95
Moss phytomass135 ± 17419 ± 69
Above-ground phytomass of grasses 5 ± 24 ± 1
Above-ground phytomass of shrubs 118 ± 7460 ± 112
Below-ground phytomass of grasses (incl. sedges) 53 ± 228 ± 5
Below-ground parts of shrubs 629 ± 101386 ± 127
Total (except wooden fractions)940 ± 2912297 ± 220
Total (incl. wooden fractions/pine trees)8964 ± 1953701 ± 281
Table 3. Above-ground live biomass of shrubs at two study sites, g/m2.
Table 3. Above-ground live biomass of shrubs at two study sites, g/m2.
Chamaedaphne calyculataLedum palustreVaccinium vitis-idaea
Study siteGreenShootsGreenShootsGreenShoots
KR9.329.77.224.119.621.4
NR37.2179.650.5172.15.72.9
Table 4. Different fractions of Net Primary Production (NPP) in bog/ryam ecosystems (g/m2) as measured at western (KR) and eastern (NR) study sites.
Table 4. Different fractions of Net Primary Production (NPP) in bog/ryam ecosystems (g/m2) as measured at western (KR) and eastern (NR) study sites.
Net Primary Production (NPP) KRNR
ANP 1 of pine trees51 ± 348 ± 5
ANP of grasses5 ± 14 ± 1
ANP of shrubs39 ± 7116 ± 22
ANP of Sphagnum mosses55 ± 8156 ± 30
BNP 2 of grasses48 ± 934 ± 7
BNP of shrubs96 ± 20157 ± 30
BNP of pine trees451 ± 8057 ± 10
Total ANP (except wooden fractions)99 ± 5276 ± 43
Total BNP (except wooden fractions)144 ± 42191 ± 40
Total NPP (ANP + BNP, except wooden fractions)243 ± 57467 ± 59
Total ANP150 ± 26324 ± 43
Total BNP595 ± 98248 ± 85
Total NPP (ANP + BNP)745 ± 152572 ± 111
Notes: 1 ANP is above-ground fraction of Net Primary Production (NPP). 2 BNP is below-ground fraction of NPP.
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Kosykh, N.P.; Koronatova, N.G.; Mironycheva-Tokareva, N.P.; Vishnyakova, E.K.; Ivchenko, T.G.; Kurbatskaya, S.S.; Peregon, A.M. The Bogs in a Forest–Steppe Region of Western Siberia: Plant Biomass and Net Primary Production (NPP). Water 2023, 15, 3526. https://doi.org/10.3390/w15203526

AMA Style

Kosykh NP, Koronatova NG, Mironycheva-Tokareva NP, Vishnyakova EK, Ivchenko TG, Kurbatskaya SS, Peregon AM. The Bogs in a Forest–Steppe Region of Western Siberia: Plant Biomass and Net Primary Production (NPP). Water. 2023; 15(20):3526. https://doi.org/10.3390/w15203526

Chicago/Turabian Style

Kosykh, Natalia P., Natalia G. Koronatova, Nina P. Mironycheva-Tokareva, Evgenia K. Vishnyakova, Tatiana G. Ivchenko, Svetlana S. Kurbatskaya, and Anna M. Peregon. 2023. "The Bogs in a Forest–Steppe Region of Western Siberia: Plant Biomass and Net Primary Production (NPP)" Water 15, no. 20: 3526. https://doi.org/10.3390/w15203526

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