Highly Productive Boreal Ecosystem Chernevaya Taiga - Unique Rainforest in Siberia (original) (raw)
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Highly Productive Boreal Ecosystem Chernevaya
2020
Boreal forests are one of the largest stores of carbon on Earth, and two-thirds of them are 16 located in Siberia. Despite the fact that these forests have a significant influence on the global 17 climate, they continue to remain understudied. Chernevaya taiga is a unique example of a highly 18 productive Siberian boreal ecosystem. This type of forest is characterized by a series of unique 19 ecological traits, the most notable of which are the gigantism of the perennial herbaceous plants and 20 bushes, complete lack of moss cover on soil surface, and the type of soil it grows on, notable for its 21 particularly high rate of decomposition of vegetative remains and low humic acid content. 22 Abundant rainfall actively washes out nutrients from the top layers of the soil, but its fertility level 23 remains very high. In fact, based on the existing data, it is twice as high as that of fertilized 24 agricultural lands. In some ways the conditions within this type of forest closely resem...
Long-term forest composition and its drivers in taiga forest in NW Russia
Vegetation History and Archaeobotany, 2015
Understanding the processes behind long-term boreal forest dynamics can provide information that assists in predicting future boreal vegetation under changing environmental conditions. Here, we examine Holocene stand-scale vegetation dynamics and its drivers at the western boundary of the Russian taiga forest in NW Russia. Fossil pollen and conifer stomata records from four small hollow sites and two lake sites are used to reconstruct local vegetation dynamics during the Holocene. Variation partitioning is used to assess the relative importance of the potential drivers (temperature, forest fires and growing site wetness) to the long-term stand-scale dynamics in taiga forest. All the main tree taxa, including the boreal keystone species Picea abies (Norway spruce) and Larix sibirica (Siberian larch), have been locally present since 10,000 cal yr BP. The constant Holocene presence of L. sibirica at three small hollow sites suggests a fast postglacial immigration of the species in northern Europe. Picea was present but not dominant at all study sites until its expansion between 8,000 and 7,000 cal yr BP markedly changed the forest structure through the suppression of Betula (birch), Pinus (pine) and Larix. Our results demonstrate that in general, the Holocene forest dynamics in our study region have been driven by temperature, but during short intervals the role of local factors, especially forest fires, has been prominent. The comparison between sites reveals the importance of local factors in stand-scale dynamics in taiga forests. Therefore, the future responses of taiga forest to climate change will be predominantly modulated by the local characteristics at the site. Keywords Variation partitioning Á Holocene Á Standscale dynamics Á Boreal biome Á Larix sibirica Á Picea abies Communicated by M.-J. Gaillard.
Aleinikov A.A., Smirnov N.S., Smirnova O.V. Tall-Herb Boreal Forests on North Ural // Russian Journal of Ecosystem Ecology, 2016, Vol. 1 (3), pp. 1-13., 2016
One of the pressing aims of today’s natural resource management is its re-orientation to preserving and restoring ecological functions of ecosystems, among which the function of biodiversity maintenanceplays an indicator role. The majority of today’s forests have not retained their natural appearance as the result of long-standing human impact. In this connection, refugia studies are becoming particularly interesting, as they give us an insight into the natural appearance of forests. Materials and methods. Studies were performed in dark conifer forests of the Pechora–Ilych reserve, in the lower reaches of the Bol’shaya Porozhnyaya River in 2013 yr. Vegetation data sampling was done at 50 temporary square plots of a fixed size (100 m2) randomly placed within a forest type. A list of plant species with species abundance was made for each forest layer. The overstorey (or tree canopy layer) was denoted by the Latin letter A. The understorey layer (indicated by the letter B) included tree undergrowth and tall shrubs. Ground vegetation was subdivided into the layers C and D. Layer C (field layer) comprised the herbaceous species (herbs, grasses, sedges) and dwarf shrubs together with low shrubs, tree and shrub seedlings. The height of the field layer was defined by the maximal height of the herbaceous species, ferns, and dwarf shrubs; the height varied from several cm to more than 200 cm in the ‘tall-herb’ forest types. Layer D (bottom layer) included cryptogamic species (bryophytes and lichens). Species abundance in the each layer was usually assessed using the Braun-Blanquet cover scale (Braun-Blanquet 1928). The nomenclature used follows Cherepanov’s (1995) for vascular plants, and Ignatov & Afonina’s (1992). Results. The present article contains descriptions of unique tall-herb boreal forests of European Russia preserved in certain refugia which did not experience prolonged anthropogenic impact or any other catastrophes. Comparative research into species and ecological diversity of typical (anthropogenically transformed) and unique (tall-herb) boreal forests has been conducted. On the basis of the collected field data, a map of the diffuse area for tall-herb boreal forests has been compiled and a set of species characteristic for these forests has been determined. The obtained data fundamentally change our notions of potential vegetation in boreal forests. Conclusions. Considerable species- and ecological diversity of tall-herb forest flora fundamentally changes our notion of the appearance of European boreal forests and determines their unique role in maintaining the highest possible level of biodiversity. The presence of tall-herb forests in various parts of eastern European taiga together with Eurasian habitats of most tall-herb species lead us to a suggestion that it is exactly this type of forests that represented the prehistoric boreal forests. In this connection, further research into still preserved fragments of tall-herb forests within the boundaries of northern Eurasia acquires huge significance. This research will help put forward systems of forest management aimed at restoring potential biodiversity of boreal forests in general
Phytomass (live biomass) and carbon of Siberian forests
Biomass and Bioenergy, 1998
AbstractÐThe results of the phytomass (live biomass) estimates inventory for the Siberian forests are presented. These results are based on the following: (i) models estimating basic phytomass fractions for eight main forest-forming species (pine, spruce, ®r, larch, Russian cedar, birch, aspen, oak); (ii) an ecoregional division of the territory into 63 ecological regions; and (iii) data from the State Forest Account (SFA) of 1993. The models are in the form of multidimensional regression equations for the ratio R fr =M fr /GS, where M fr is the mass of a phytomass fraction in teragrams (Tg), and GS is (green) growing stock in cubic meters (m 3 ). The independent variables used are age, site index and relative stocking of stands. The fractions evaluated are wood and bark of the stems, bark, wood and bark of branches, foliage, stump and roots, understorey and green forest¯oor. The ®nal results are presented by 18 administrative units and three economic regions. The total phytomass of the vegetation of forest ecosystems of the total forested areas in Siberia is estimated to be 48 253.8 Tg of dry organic matter, of which 59.2% are stems, 18.4% stump and roots, 8.4% branches, 5.6% green forest cover, 3.4% foliage, 2.1% understorey and an additional 2.9% of the total phytomass is in the form of shrubbery areas. Due to Russian forest terminology, forested areas, i.e. closed forests, include forests generated by: (i) so-called main forest-forming species combined in three groups (coniferous, hard-leaved deciduous and softleaved deciduous); (ii) other species (rare, valuable and introduced species) with small area; (iii) shrubbery areas, considered as forested areas for territories where forests are not able to grow due to severe climatic conditions (zonal and altitudinal tree lines). The average density of phytomass (as an average of the total forested areas) is 4.04 kg of carbon (C) per square meter and varies from 2.0 kg C/m 2 (in ecoregions of the forest tundra) to 5.7±5.9 kg C/m 2 (in southern taiga and mixed broadleaved coniferous forests in the Far East). The C dynamics over time that have been estimated based on ocial forest inventory data for 1961±1993 reveal that during this period the Siberian forests were, on average, a small source of C emissions (about 20 Tg C/year). For`reconstructed' dynamics of the growing stock, which take into account systematic errors in the forest inventory data, the Siberian forests were estimated on average to sequester carbon (51 Tg C/year). Both approaches provide the conclusion that during the 10 years between 1983 and 1992 the Siberian forests have been a net source of atmospheric carbon (between 81 and 123 Tg C/year). #
Net CO2 exchange rates in three different successional stages of the "Dark Taiga" of central Siberia
Tellus B, 2002
The net ecosystem exchange (NEE) of successional stages of the Abies-dominated dark taiga was measured in central Siberia (61 • N 90 • E) during the growing season of the year 2000 using the eddy covariance technique. Measurements started before snow melt and canopy activity in spring on day of year (DOY) 99 and lasted until a permanent snow cover had developed and respiration had ceased in autumn DOY 299. Three stands growing in close vicinity were investigated: 50 yr-old Betula pubescens ("Betula stand", an early successional stage after fire), 250 yr-old mixed boreal forest, representing the transition from Betula-dominated to Abies-dominated canopies, and 200-yr-old Abies sibirica ("Abies stand", representing a late successional stage following the mixed boreal forest). The mixed boreal forest had a multi-layered canopy with dense understory and trees of variable height and age below the main canopy, which was dominated by Abies sibirica, Picea obovata and few old Betula pubescens and Populus tremula trees. The Abies stand had a uniform canopy dominated by Abies sibirica. This stand appears to have established not after fire but after wind break or insect damage in a later successional stage. The stands differed with respect to the number of days with net CO 2 uptake (Betula stand 89 days, mixed boreal forest 109 days, and Abies stand 135 days), maximum measured LAI (Betula 2.6 m 2 m −2 , mixed boreal forest 3.5 m 2 m −2 and Abies stand 4.1 m 2 m −2 ) and basal area (Betula stand 30.2 m 2 ha −1 , mixed boreal forest 35.7 m 2 ha −1 , and Abies stand 46.5 m 2 ha −1 ). In the mixed boreal forest, many days with net daytime CO 2 release were observed in summer. Both other sites were almost permanent sinks in summer. Mean daytime CO 2 exchange rates in July were −8.45 µmol m −2 s −1 in the Betula stand, −4.65 µmol m −2 s −1 in the mixed boreal forest and −6.31 µmol m −2 s −1 in the Abies stand. Measured uptake for the growing season was −247.2 g C m −2 in the Betula stand, −99.7 g C m −2 in the mixed boreal forest and −269.9 g C m −2 in the Abies stand. The total annual carbon uptake might be slightly lower (i.e. less negative) due to some soil respiration under snow in winter. The study for the first time demonstrates that old forests in the "Dark Taiga" are carbon sinks and that sink activity is very similar in late and early successional stages. Canopy and crown structure with associated self-shading and available radiation are suggested as possible causes for the observed differences.
Carbon balance of a southern taiga spruce stand in European Russia
Tellus B, 2002
We present results from nearly three years of net ecosystem flux measurements above a boreal spruce stand growing in European Russia. Fluxes were measured by eddy covariance using conventional techniques. In all years examined (1998)(1999)(2000), the forest was a significant source of carbon to the atmosphere. However, the magnitude of this inferred source depended upon assumptions regarding the degree of "flux loss" under conditions of low turbulence, such as typically occur at night. When corrections were not made, the forest was calculated to be only a modest source of C to the atmosphere (3-5 mol C m −2 yr −1 ). However, when the corrections were included, the apparent source was much larger (20-30 mol C m −2 yr −1 ). Using a simple model to describe the temperature dependencies of ecosystem respiration on air and soil temperatures, about 80% of the night-time flux was inferred to be from soil respiration, with the remainder being attributable to foliage, branches and boles. We used reasonable assumptions to estimate the rate of ecosystem respiration during the day, allowing an estimation of canopy photosynthetic rates and hence the annual Gross Primary Productivity of the ecosystem. For the two full years examined (1999 and 2000), this was estimated at 122 and 130 mol C m −2 yr −1 , respectively. This value is similar to estimates for boreal forests in Scandinavia, but substantially higher than has been reported for Canadian or Siberian boreal forests. There was a clear tendency for canopy photosynthetic rates to increase with both light and temperature, but the slope of the temperature response of photosynthesis was less steep that that of ecosystem respiration. Thus, on most warm days in summer the forest was a substantial source of carbon to the atmosphere; with the forest usually being a net sink only on high insolation days where the average daily air temperatures were below about 18 • C. These data, along with other studies on the current balance of boreal ecosystems, suggests that at the current time many boreal forests might be releasing substantial amounts of carbon dioxide to the atmosphere. This observed temperature sensitivity of this ecosystem suggests that this might be a consequence of substantially higher than average temperatures over recent years.
Oecologia, 2006
To investigate the variability of primary production of boreal forest ecosystems under the current climatic changes, we compared the dynamics of annual increments and productivity of the main components of plant community (trees, shrubs, mosses) at three sites in the north of Siberia (Russia). Annual radial growth of trees and shrubs was mostly defined by summer temperature regime (positive correlation), but climatic response of woody plants was species specific and depends on local conditions. Dynamics of annual increments of mosses were opposite to tree growth. The difference in climatic response of the different vegetation components of the forest ecosystems indicates that these components seem to be adapted to use climatic conditions during the short and severe northern summer, and decreasing in annual production of one component is usually combined with the increase of other component productivity. Average productivity in the northern forest ecosystems varies from 0.05 to 0.14 ...
Functional Ecology, 2000
In central Siberia Pinus sylvestris forests and bogs are common elements of the landscape and they show different functional behaviour in terms of energy and carbon exchanges. 2. The two ecosystems show a remarkable difference in energy dissipation, with average Bowen ratios of 0·6 and 2·9, respectively. 3. The alternation of bogs and forests with different energy partition at the surface could affect rainfall distribution and the disturbance regimes (lightening and fires) and drive the ecology of such a complex landscape. 4. During summer, water shortage and poor nutrient conditions in the soil heavily affect carbon exchange rates of the regenerating forest (-7·7 mmol m -2 day -1 ). Consequently the bog becomes a significant dominant carbon sequestration element of this particular landscape with higher rates of carbon uptake (-104·2 mmol m -2 day -1 ).
Carbon deposition by Russian forests on the example of taiga and forest-steppe zones
Ecological Questions
Due to the global warming of the climate, the assessment of the carbon cycle in forest ecosystems has become particularly important. One method for determining deposited carbon is based on the use of biomass expansion factors (BEF) and State Forest Inventory (SFI) data. By combining BEF models with SFI data in two ecoregions of Russia-taiga and forest-steppe-it was found that over a 20-25-year period, accumulating the carbon deposition in the taiga zone is significantly less (5%) compared to the forest-steppe zone (39%). Comparable results were obtained by the same method in different ecoregions of the planet (from 8% in 5 years in China to 68% in 50 years in Japan). A comparison of the results obtained by the proposed method and the IIASA method showed a minimal discrepancy (3 %), which gives reason to consider the above estimates of carbon deposition close to reality. However, uncertainties remain related to the quality of the SFI data and the carbon deposition in the soil.