Below-ground Phytomass Research Articles

Phytomass carbon pool dynamics in the reference fir stands of the taiga zone

The present study resulted in quantitative estimation of phytomass carbon dynamics in fir-dominated stands based on growth rate table built for reference stands. The study area covered fir-dominated stands of the third bonitet class (mid-productivity stands). Studied stands belong to feather moss and herb-rich forest types and grow in taiga zone (Yeniseiskoe Forestry, Krasnoyarsk Krai, Russia). Mathematical models of changes in stands characteristics in reference fir stands are presented. Carbon pool in above-ground and below-ground phytomass fractions were assessed at different age classes using conversion-volume method. The results are important when assessing the role of fir stands of a certain age in the overall carbon budget at the regional level. Moreover, the results may be used in continuous or periodic assessment of the amount of greenhouse gas absorbed by forest ecosystems and in other types of environmental monitoring.

Annual Carbon Budget of Biogenic Greenhouse Gases under Mixed Land Use: Lgov District as a Model Object of the Central Chernozem Zone, Russia

A comprehensive study of the net carbon balance of Lgov administrative district (Kursk oblast) in the Chernozem zone of the European part of Russia is carried out. The data sources included field estimates of carbon dioxide and methane exchange between soil and atmosphere, above- and below-ground phytomass stocks, simulation models parameterized on these data, official statistical and meteorological information, and published scientific data. Watered filtration fields of waste disposal sites of sugar industry are responsible for 26% of CH4 emissions from the territory of the district, although they occupy only 0.04% of its area. The maximum of CO2 emission is found at volumetric soil moisture of 30%, whereas, with exceeding this value, methane emission begins to rise linearly, reaching a maximum on the open surface of water reservoirs, and among them – on watered filtration fields. Another significant local source of methane is compost storages (22%). However, water reservoirs and ponds are the largest source of CH4 (43%). Amongst the net sources of CO2 the combustion of fossil fuels by transport and agriculture machinery predominates (22.3%). In contrast to methane, which emission is mainly determined by powerful point sources, the input of net fluxes of CO2 positively correlates with their area. Currently observed low rate net CO2 flux in the district area (–6.4 g C m–2 per year), is decisively overlapped by local methane sources (+95 g C (CO2-eq.) m–2 per year). The influence of the types of land use and methods of calculation on the C-balance of the territory in study, and a way of its transformation into a carbon-neutral state are discussed.

Response of soil hydrothermal processes within the active layer to variable alpine vegetation conditions on the Qinghai‒Tibet Plateau

Alpine vegetation plays an important role in the thermal stability of the permafrost under a warming climate, as it affects ground hydrothermal dynamics. The response of soil hydrothermal dynamics in the active layer to permafrost degradation under different alpine grassland types is unclear on the Qinghai‒Tibet Plateau. In this study, long-term soil temperature and soil water content in the active layer were monitored in situ from October 2010 to December 2018 at five sites in the Kaixinling permafrost region on the interior Qinghai‒Tibet Plateau along the Qinghai–Tibet Railway. The sites included an alpine steppe (AS), three alpine meadows (AM) with different degrees of degraded vegetation, and an alpine swamp meadow (ASM). Based on field-monitored data, the variations in soil temperature, soil water content, and freeze–thaw processes were examined in the active layer. The response characteristics of the soil hydrothermal processes to climate change were analysed under the different alpine grasslands. The results showed that the duration of the thawing and freezing stages of the active layer of the AMs was shorter than that of the ASM and the AS. The average mean annual soil temperature (MAST) in the active layer of the AM ((−1.25 ± 0.50) °C) was lower than those in the AS ((−0.71 ± 0.39) °C) and ASM ((−0.45 ± 0.57) °C), while the AM had the highest rate of soil temperature increase ((0.2 ± 0.06) °C per year). The annual amplitude of ground temperature in the active layer increased with the transition direction of the alpine vegetation type from ASM to AM to AS. The small surface offset (SO) and thermal offset (TO) (absolute values) indicated that the ground thermal state of the AM was more unstable, as it was more sensitive to the increase in air temperature than the ASM or the AS. Soil properties controlled the distribution of soil water content within the active layer, but vegetation improved the shallow soil structure by producing more belowground phytomass, thus, enhancing soil water content in the 0–30 cm layer. The average soil water content at depths of 0–30 cm was directly proportional (p < 0.05) to the phytomass. Soil water contents at depths of 0–30 cm in the ASM ((37.7 ± 5.3)%) and the AM ((40.8 ± 5.9)%) were significantly higher than those in the AS ((22.7 ± 3.2)%). These results provide valuable insight into the hydrothermal interactions between the degradation of permafrost and alpine vegetation under a warming climate.

Field-Layer Vegetation and Water Table Level as a Proxy of CO2 Exchange in the West Siberian Boreal Bog

The Mukhrino field station has participated in the national project on the inventory of carbon fluxes and pools in the terrestrial ecosystems of Russia since 2022. The development of a network of measurements of CO2 fluxes and phytomass covered six types of bog ecosystems typical to Western Siberia. The gross ecosystem exchange (GEE) of the field-layer vegetation (medians for the period from the end of May to the end of July, mgC m−2 h−1; see errors in Results section) decreased in series: Sphagnum bog with sparse low pine trees (“Open bog”), ridges in ridge-hollow patterned bogs (“Ridge”), pine-dwarf shrub-Sphagnum bog (“Tall ryam”), hollows in patterned bogs (“S.hollow”, “E.hollow”) and pine-dwarf shrub-Sphagnum bog (“Ryam”): −220, −200, −125, −120, −109 and −86, respectively. Ecosystem respiration (Reco) here was 106, 106, 182, 55, 97 and 136. The aboveground and belowground phytomass of mosses in this series varied between 368 ± 106–472 ± 184 and 2484 ± 517–6041 ± 2079 g/m2, respectively: the aboveground phytomass of vascular plants and plant litter—15 ± 7–128 ± 95 and 10 ± 6–128 ± 43, respectively. According to the results of mathematical modeling, the best proxy for GEE, in addition to photosynthetically active radiation and soil surface temperature, was the aboveground phytomass of vascular plants (PhV), and for Reco—PhV and the mass of the plant litter of vascular plants.

Root systems reserve under humid conditions of floodplain meadows of the Ob River in the subzone of the southern taiga

The results of the study of the underground phytomass of the floodplain meadow communities in the Middle Ob obtained from three permanent sample plots in the area of the Kaibasovo research station of Tomsk University (Kri-vosheinsky district of the Tomsk region) are presented. The functioning and productivity of grassland ecosystems should be carefully studied, especially in the light of ongoing climate change, as they are actively involved in the carbon cycle. However, the belowground phytomass is given much less attention in the literature than the aboveground part, despite the fact that they are equally important for the study of the cycle. The study of vegetation cover in order to analyze the biological cycle of flood-plain ecosystems, the production and destruction of plant matter in this area was practically not carried out. The goal was to assess the structure and stock of root phytomass in the meadows of the Ob floodplain. In the course of the work, the hydro-climatic conditions of the growing season of the current and previous years were characterized in order to assess their impact on root development. The reserves of underground organs in the 0-20 cm soil layer were determined, the limits of fluctuations of the total reserves of roots in the 0-20 cm layer between the sampling periods in June and August were established.&#x0D; Key words. Belowground biomass, flood, floodplain meadows, productivity, roots, Western Siberia.

Effects of land use and climate on carbon and nitrogen pool partitioning in European mountain grasslands

European mountain grasslands are increasingly affected by land-use changes and climate, which have been suggested to exert important controls on grassland carbon (C) and nitrogen (N) pools. However, so far there has been no synthetic study on whether and how land-use changes and climate interactively affect the partitioning of these pools amongst the different grassland compartments. We analyzed the partitioning of C and N pools of 36 European mountain grasslands differing in land-use and climate with respect to above- and belowground phytomass, litter and topsoil (top 23 cm). We found that a reduction of management intensity and the abandonment of hay meadows and pastures increased above-ground phytomass, root mass and litter as well as their respective C and N pools, concurrently decreasing the fractional contribution of the topsoil to the total organic carbon pool. These changes were strongly driven by the cessation of cutting and grazing, a shift in plant functional groups and a related reduction in litter quality. Across all grasslands studied, variation in the impact of land management on the topsoil N pool and C/N-ratio were mainly explained by soil clay content combined with pH. Across the grasslands, below-ground phytomass as well as phytomass- and litter C concentrations were inversely related to the mean annual temperature; furthermore, C/N-ratios of phytomass and litter increased with decreasing mean annual precipitation. Within the topsoil compartment, C concentrations decreased from colder to warmer sites, and increased with increasing precipitation. Climate generally influenced effects of land use on C and N pools mainly through mean annual temperature and less through mean annual precipitation. We conclude that site-specific conditions need to be considered for understanding the effects of land use and of current and future climate changes on grassland C and N pools.

. Productivity changes of wetland and grassland ecosystems along a latitudal gradient

The aim of the study. Analysis of changes in the productivity of dwarf shrub-moss-lichen, pine-dwarf shrub-sphagnum and sedge-sphagnum and grass ecosystems along the latitudinal gradient. Methodology. For a number of bog and grass ecosystems located along a latitudinal gradient from 65 to 50° N in the range of longitudes from 63 to 95° E the stocks of live and dead, aboveground and belowground phytomass, as well as the values of aboveground (ANP), belowground (BNP) and total production (NPP) were analyzed. The data are given for 45 ecosystems grouped into 12 types from forest-tundra mires to desert steppes. The vegetation of ecosystems is represented by bog one (mosses, shrubs and grasses) to the steppe (mesoxerophytic and xerophytic grasses). Since the spread of data on stocks and production for individual ecosystems is large, we present averaged data for ecosystem types. Main results. The largest stock of green phytomass was obtained for floodplain meadows (7 t/ha), the smallest stock was found in the desert steppes (0.8 t/ha). The stock of dead aboveground phytomass was maximal in the fens of the forest-steppe zone (10 t/ha) and minimal in the oligotrophic hollows of boreal bogs (0.3 t/ha). The stock of living belowground organs decreases along a latitudinal gradient from 20 (true steppes) to 3 t/ha (desert steppes), whereas the stock of dead belowground organs decreased from 79 (fens of the forest-steppe zone) to 4 t/ha (in the ryams of the middle taiga and desert steppes). Above-ground production was estimated as highest in the fens of the forest-steppe zone (12), decreasing along the latitudinal gradient down to the desert steppes (1 t/ha per year). Belowground production in all types of ecosystems studied was higher than the above-ground one, ranging from 45 (fens of the forest-steppe zone) to 3 t/ha per year (mires in the forest-tundra). The NPP value in some of the studied ecosystems varied from 57 (fens of the forest-steppe zone) to 5 t/ha per year (mires in the forest-tundra). The BNP/ANP ratio averaged over ecosystem types was maximal in the desert steppes (5.9) and minimal in floodplain meadows (1.9). In the range of latitudes 56-52°N, where steppe meadows, meadow steppes and true steppes located, the NPP, averaged over these ecosystems, varied from 22 to 24 t/ha per year. These ecosystems the most fertile soils of the region, i.e. meadow chernozem and ordinary chernozem (Phaeozems) were developed. To the north and south of this area, the NPP value decreases: to the north due to the lack of heat, and to the south due to lack of moisture. Conclusions. In the biotic cycle in mires differs from that in meadows and steppes by the annual sequestration of a part of the carbon influx in the forming peat. This amount of carbon sequestration is about 10% of the NPP of the wetland ecosystem. In the climax grass ecosystems, the carbon influx is equal to its outflux. These ecosystems are acting as gas exchangers between plants, soil and atmosphere. In contrast to grasslands, wetlands are acting as carbon accumulators that lower the CO2 in the air.

The effect of temperature fields on soil and plant cover formation in arid ecosystems of the Uvs Nuur basin

Introduction of remote and automated methods into the practice of soil and ecological studies urges for development of the methodological basis for combined analyses of surface and satellite data. The aim of the study was to explore the possibility to identify and typologise the structural and functional borders of soil cover using temperature fields, obtained by combined analysis of the temperature time series obtained by field and remote temperature monitoring. The functional relationships that are expressed within geosystems as the flux of energy and matter are reflected in soil temperature regimes, hydrophysical soil properties and plant cover biological productivity, which were studied in the arid ecosystems of the Uvs Nuur depression in Tuva, Russia. The quantitative characteristic of the temperature fields of the psammophytic soils were obtained, and the effect of hydrothermal conditions and soil hydrophysical properties on above- and belowground phytomass stocks of the sand massif Zuger-Els revealed and discussed.

Effects of fire on production and destruction processes in steppe phytocenoses of Burtinskaya Steppe, Orenburg Nature Reserve

The paper deals with the production and destruction process in burned and unburned (control) steppe phytocenoses. The fire occurred in August 2014, after which a monitoring network consisting of 6 sites was laid out. During two vegetation seasons (2015 – 2016), we surveyed above-ground and below-ground phytomass stocks and on their basis production and destruction amounts in phytocenoses were calculated. Comparative analysis of control and burned communities revealed higher production and destruction of above-ground phytomass components in both years. With the general tendency for most phytocenoses to reduce above-ground production and increase litter in the second year of the survey, the first process was more intense in burned phytocenoses that were exposed to anthropogenic load in the past, and the second process occurred in almost all burned communities. In the below-ground sphere, mineralization processes were more intense during the entire survey period on control sites, and an increase in the mass of living and dead below-ground organs was more determined by the phytocenoses specifics, rather than their damage by fire.

Changes in Soil Features and Phytomass during Vegetation Succession in Sandy Areas

This research was conducted on an area of inland sands characterised by various degrees of overgrowth by vegetation and soil stabilisation. This landscape’s origin is not natural but is connected to human industrial activities dating from early medieval times, which created a powerful centre for mining and metallurgy. This study aims to identify the changes in the above- and belowground phytomass in the initial stages of succession and their influence on the chemical properties and morphology of the soil. It was found that Salix arenaria dominated in primary phytomass production in all plots tested. The amounts of this species found in each community were as follows: 8.55 kg/400 m2 (algae–mosses), 188.97 kg/400 m2 (sand grassland–willow), 123.44 kg/400 m2 (pine–willow–mosses), 14.63 kg/400 m2 (sand grassland–mosses–willow), and 196.55 kg/400 m2 (willow–pine–sand grassland). A notable share of Koeleria glauca was found in the phytomass production of Plots IV (45.73 kg) and V (86.16 kg). Basic soil properties (pH, Corg, Nt), available plant elements (P), and plant nutrients (Ca, Mg, K, P, Fe) beneath the dominant plant species were examined. Soil acidity (pH) varied greatly, ranging from acidic (pH = 3.2) to weakly acidic (pH = 6.3). The content of organic carbon (Corg) in individual plots beneath the dominant species in the humus horizon ranged from 0.28% to 1.42%. The maximum contents of organic carbon and total nitrogen were found in organic (O) and organic-humus (OA) horizons. The highest Pavail content was found in organic and organic-humus horizons, ranging from 10.41 to 65.23 mg/kg, and in mineral horizons under K. glauca (24.10 mg/kg) and Salix acutifola (25.11 mg/kg). The soil features and phytomass were varied differently across individual sites, representing different stages of succession.

The effect of grazing and weather conditions on the productivity of Tyva dry steppes, Russia

The aim of the study. To investigate specifics of plant production process in steppe pastures in Tyva. Location and place of the study. The study was performed in 1998-2000 and 2008-2010 in five pasture ecosystems in the Ubsu-Nur depression in Tyva, Russia. Methodology. Field and laboratory work was carried out to assess the biological productivity of pasture ecosystems employing conventional geobotanical, botanical and ecological methods. Main results. The study showed that all characteristics of production process change with grazing pressure and weather conditions of the year. The highest grazing pressure was observed at the Erzin pasture, whereas the lowest pressure was found at the Yamaalyg one. The green phytomass stock (G) at the Erzin pasture during all years varied within 0.3–0.6 Mg ha-1, whereas the living belowground stock (R) during six years ranged 4.5–11.5 Mg ha-1. The Yamaalyg pasture had the lowest and the highest G of 0.5 and 1.1 Mg ha-1, respectively, with the minimal and maximal R estimates of 7.8 and 20.1 Mg ha-1, respectively. Therefore it was concluded that both under the highest (Erzin) and lowest (Yamaalyg) grazing pressure the between-years dynamics (over six years) may change as much as 2–3 times. Phytomass production was shown to vary much more. The aboveground production (ANP) at Erzin pasture was found to change from 0.4 to 1.2 Mg ha-1yr-1, i.e.3-fold. At the Yamaalyg pasture ANP changed 1.2 to 2.0 Mg ha-1yr-1. The belowground phytomass production (BNP) was shown to vary much more as compared with the aboveground production: from 2.7 to 24.5 Mg ha-1yr-1. Some production characteristics were shown to be weather-associated. At one and the same pasture (Onchalaan), depending on the weather conditions, ANP and BNP were found to vary 4 times, i.e. from 0.9 to 3.7 Mg ha-1yr-1 and from 4 to 18 Mg ha-1yr-1, respectively. The highest grazing pressure resulted in less yearly variation, as ANP ranged 0.4–0.8 Mg ha-1yr-1, and BNP ranged 5–8 Mg ha-1yr-1. Such lesser variation was apparently due to the higher resilience of the dominating herbs and grasses to grazing. Analysis of the influence of weather conditions showed that abundant summer precipitation resulted in the highest ANP estimates. No correlation was revealed between BNP and weather conditions. Overall seasonal hydrothermal conditions, such as warm and wet autumn of the preceeding year and rainy summer of the current year) were beneficial for the aboveground plant production. Conclusion. The phytomass stock the in grazed dry steppes of Tyva was found to vary more as compared with phytomass production. Belowground production showed especially drastic changes from year to year. Increased ANP almost always results in decreased belowground living phytomass stock and often in decreased BNP due to modified nitrogen turnover under grazing. The BNP estimate is extremely volatile and does not follow the aboveground phytomass dynamics.The highest BNP in 2008 could not be attributed only to weather conditions, being most likely due to the increased solar radiation. Spatial and temporal dynamics of the phytomass production showed that the maximal green phytomass and dead belowground phytomass stocks, as well as ANP, displayed greater spatial variation as compared with the temporal one. Overall we conclude that despite different methods to study phytomass production, its spatial and temporal variation is about the same.

Productivity of grassland ecosystems in the Tyva Republic, Russia

The aim of the study. The aim of the study was to estimate biological productivity of Tyva grasslands. Location and time of the study. The living and dead above- and belowground phytomass, as well as net primary production, were estimated in the montane ecosystems and depressions of the Tyva Republic, Russia. Methodology. Field and laboratory studies of the biological production by grasslands were conducted using botanical, geobotanical and ecological methods. Main results. In the montane ecosystems the aboveground phytomass production was shown to range from 1.3 to 3.6 Mg ha-1 yr-1, whereas the belowground production was evaluated as ranging 10-65 Mg ha-1 yr-1. The belowground production was found to vary widely, being associated with location of mountain ridges, slope geomorphology and grazing, but no association was found with the altitude. In depressions the average green phytomass stock changed from 0.7 to 1.9 Mg ha-1, living belowground phytomass varied 3.4 to 19.3 Mg ha-1. From the meadow steppes to the deserted ones the living above- and belowground stocks decreased 2.7 and 5.7 fold, respectively, whereas the above- and belowground production was estimated to decrease 3 and 4 times, respectively. Several indices to characterize the growth and development, hence the productivity, of herbaceous plants was proposed. The values of the indices calculated for the Tyva grasslands suggested high photosynthetic activity: all studied steppes had the same share of belowground production in the total ecosystem production, i.e. 90%. The turnover rate of the living belowground phytomass was estimated to increase from meadow steppes to the deserted ones, whereas green phytomass increment, as related to its stock, slightly decreased. Conclusions. The living belowground phytomass stock was found to exceed the green phytomass stock by 5-8 times, both in montane ecosystems and depressions. Preservation of living belowground organs during hot dry summers and cold winters, when soil freezes through, is apparently indispensable for grassland survival under any climatic conditions.

ВЛИЯНИЕ ПОЖАРА НА ДИНАМИКУ ПОДЗЕМНОЙ ФИТОМАССЫ СТЕПНЫХ ФИТОЦЕНОЗОВ НА УЧАСТКЕ «БУРТИНСКАЯ СТЕПЬ» ОРЕНБУРГСКОГО ЗАПОВЕДНИКА

Steppe ecosystems are the most vulnerable to the influence of the pyrogenic factor. The study of the regularities of the vegetation cover restoration in the burnt steppe phytocenoses is urgent, as it is connected with the wide spread of fires in the steppe zone at present time. The increasing frequency and area of fires indicate a tendency of fires intensification, which ultimately can lead to significant environmental consequences. The authors studied the effect of pyrogenic factors on the dynamics of below-ground phytomass stocks of steppe phytocenoses on the territory of the sector “Burtinskaya Steppe” in Orenburg Reserve. The research area is located in the steppe zone of the Zavolzhsk-Ural region. The total area of the sector is 45 km². In August 2014, more than 20 km² of protected steppe burned on the site. After the fire two monitoring plots were laid, each plot included a control (B) and a burnt (A) plot. The research was conducted in 2015–2016. The geobotanical descriptions, registration of the above-ground and below-ground phytomass were conducted in spring, summer and autumn periods for each community. The obtained samples of below-ground phytomass were washed, dried at 105 °C and weighed. All above-ground phytomass was dried to air-dry state. The comparison of unburned and fire-damaged plots at all sites did not reveal statistically significant differences according to the nonparametric Mann-Whitney U-test (α &lt;0.05) in the total stocks of below-ground phytomass and stocks of living below-ground phytomass. Differences in the stocks of dead below-ground phytomass were revealed by the second year of the study at one plot.

Land-use Changes Alter Energy and Water Balances on an African BrachiariaPasture Replacing a Native Savanna in the Orinoco llanos

The seasonal changes in the energy balance after the substitution of a herbaceous savanna by a Brachiaria field located in the Orinoco lowlands were assessed over an entire year using the eddy covariance technique. Simultaneously, an herbaceous savanna was monitored as a control. This work provides evidence that the vegetation replacement lead to different patterns of energy and water balance. The seasonal trends of the latent heat flux (λE) to available energy (Ra) ratio tended to decrease as senescence increased due to seasonal influence of air humidity mole fraction deficit and soil water content on leaf area index (LAI) and surface conductance (gs). Therefore, the partitioning of the available energy depended on both climatological (i.e., solar radiation, volumetric soil water content and air humidity mole fraction deficit) and biological variables (i.e., conductance behavior and LAI) which were stress-induced. For the wet season, the seasonally averaged daily λE in the Brachiaria field (i.e., 0.8 ± 0.1 mm d-1) was 1.3-fold higher than that in the herbaceous savanna (i.e., 0.6 ± 0.1 mm d-1) (Mann-Whitney U-test). For the dry season, the value was 2.7 ± 0.6 and 2.2 ± 0.4 mm d-1, respectively, these means values were not significantly different. In the Brachiaria and herbaceous savanna stands, the annual evapotranspiration was 731 and 594 mm year-1, respectively, and the annual ratio of evapotranspiration to precipitation was 0.52 to 0.42 respectively. In Brachiaria field, the deep drainage was relatively lower (43% of total precipitation) than that in the herbaceous savanna stand (53%) leaving a similar amount of water to increase soil storage. The current shift in land cover decrease deep drainage and increased λE by water uptake from a pasture with high belowground phytomass and LAI.

Productivity of mire complexes of Western Siberian cryolithozone

New quantitative characteristics of ecosystem productivity in mire complexes of the Western Siberian cryolithozone are obtained. Standing crop of living above-ground and below-ground phytomass (up to 30-sm depth) in palsa complexes varied from 130 to 230 t · ha-1. Mortmass stock contributes 70% of the total plant mass. Primary production of palsa complexes in the region is about 5 t · ha-1 · year-1, that is two times lower in comparison with the production of ombrothrophic bogs in the middle taiga sobzone of Western Siberia.

ПОСЛЕПОЖАРНАЯ СУКЦЕССИЯ В ЛЕСОБОЛОТНЫХ КОМПЛЕКСАХ

The article is devoted to the study of post-pyrogenic successional changes of plant matter in the forest-mire complexes in the eastern branches of the Great Vasyugan Mire. The aim of the study was to obtain and analyze the data characterizing the post-fire dynamics of plant matter for an objective environmental assessment of the current state of forest-mire landscapes. The objects of the study were ryam communities situated between the Iksa and Bakchar rivers of the Tomsk Region and characterized by varying degrees of post-fire disturbance, which were exposed to catastrophic pyrogenic impact. Studies on the dynamics of vegetation community and plant matter at sites with varying degree of peat fire intensity were carried out for ten years. At sites with a low fire intensity, the degree of disturbance of vegetation cover was 40 – 50 %. At a mire which was exposed to the pyrogenic influence of a moderate degree, small islands with individual specimens of shrubs (Ericaceae) and small islands of Sphagnum mosses have been preserved. Mire ecosystems that have undergone a fire of the greatest intensity, are represented by burned to mineral soil depressions with islands of burnt peat. After ten years of succession in the most disturbed mire ecosystems, the percentage ratio of the above-ground phytomass to that in control sites varied within 10 % of the control phytomass. The amount of live below-ground plant matter increased very slowly, and by the tenth year of recovery, it was only 3.5 % of the stock of control underground living phytomass. The living plant matter stock at sites with moderate fire disturbance was 50 % of the control stock both in above-ground and below-ground areas. At sites of low fire intensity by the tenth year of succession, the amount of live plant matter ranged from 70–80 % of the above-ground control phytomass, and as for below-ground phytomass, the amount of living roots and rhizomes exceeded the control ones by 11 %.

The effect of decreasing permafrost stability on ecosystem carbon in the northeastern margin of the Qinghai\u2013Tibet Plateau

The objective of this study is to investigate the effect of decreased permafrost stability on carbon storage of the alpine ecosystems in the northeastern margin of the Qinghai–Tibet Plateau. During July and August 2013, we selected 18 sites in five types of permafrost (stable, substable, transitional, unstable, and extremely unstable) regions. We measured aboveground phytomass carbon (APC) and soil respiration (SR), soil inorganic carbon (SIC), soil organic carbon (SOC), belowground phytomass carbon, and soil properties down to 50 cm at same types of soils and grasslands. The results indicated that ecosystem carbon in cold calcic soils first decreased and then increased as the permafrost stability declined. Overall, decreasing permafrost stability was expected to reduce ecosystem carbon in meadows, but it was not obvious in swamp meadows and steppes. APC decreased significantly, but SIC and SOC in steppes first decreased and then increased with declining permafrost stability. Soil clay fraction and soil moisture were the controls for site variations of ecosystem carbon. The spatial variations in SR were possibly controlled by soil moisture and precipitation. This meant that alpine ecosystems carbon reduction was strongly affected by permafrost degradation in meadows, but the effects were complex in swamp meadows and steppes.

Stocks of phytomass and organic carbon in tundra ecosystems of northern Fennoscandia

This article considers carbon stocks in the tundra ecosystems of northern Fennoscandia with different meso- and macrorelief features in relation with the value and structure of the phytomass of these ecosystems and their volume weight of fine-grained soil. The basic stocks of ecosystem carbon (60–97%) are concentrated in shallow soils. The value of the soil pool of carbon is influenced not only by its concentration but also by the thickness and level of stoniness of soil horizons. Phytomass is the second most significant carbon pool. It was established that most of the tundra ecosystems have stocks of this element largely in belowground phytomass, which, on the whole, reflects the correlation between its aboveground and belowground parts. The carbon stocks in the mortmass of tundra ecosystems are comparable with or slightly exceed the carbon stocks in the live phytomass.

Linking floral biodiversity with nitrogen and carbon translocations in semi-natural grasslands in Lithuani

Abstract The aim of the present study is to evaluate the long-term effects of long-term piggery effluent application on semi-natural grassland ecotop-phytotop changes (above- and below-ground phytomass production, and carbon and nitrogen allocation in grassland communities) in relation to changes (or variability) in topsoil properties. Analysis of phytomass distribution in piggery effluent irrigated grassland communities showed that dry biomass yield varied from 1.7−5.3 t ha-1. Variability in soil and plant cover created a unique and highly unpredictable site specific system, where long-term anthropogenic influences established successor communities with specific characteristics of above- and below-ground biomass distribution. These characteristics depend more on grassland communities than on soil chemical properties. Families of grasses (Poaceae) dominated the surveyed communities and accumulated most carbon and least nitrogen, while legumes accumulated most nitrogen and lignin and least carbon. Carbon concentrations in above-ground biomass had minor variations, while accumulation of nitrogen was strongly influenced by species diversity (r = 0.94, n = 10, p &lt;0.001) and production of above-ground biomass

Micromosaic structure and phytomass of ground vegetation in main types of dark conifer forests in the Pechora-Ilych state nature reserve

The micromosaic structure of plant communities in dark conifer forests of dwarf shrub-true moss, boreal small herb-true moss, tall fern, and boreal tall herb subsections was studied in the Pechora-Ilych reserve. A typological scheme of microsites was constructed and the alpha-diversity of plants was assessed in microsites of different types; dominant and high-constancy species were identified. The proportions of area occupied by different microsites in test plots were calculated, and amounts of aboveground and belowground phytomass were estimated for every vascular plant species, dominant moss species, and the moss synusia as a whole in microsites of each type.