Aggregated Estimation of the Basic Parameters of Biological Production and the Carbon Budget of Russian Terrestrial Ecosystems: 1. Stocks of Plant Organic Mass

The data presented were obtained at the first stage (1993–1999) of studies on evaluating the basic parameters of biological production in Russian terrestrial ecosystems in order to provide information for assessing and modeling the carbon budget of the entire terrestrial biota of the country. Stocks of phytomass (by fractions), coarse woody debris, and dead roots (underground necromass) were calculated by two independent methods, which yielded close results. The total amount of phytomass in Russian terrestrial ecosystems was estimated at 81800 Tg (=10¹² g = million t) dry matter, or 39989 Tg carbon. Forest ecosystems comprise a greater part (82.1%) of live plant organic matter (here and below, comparisons are made with respect to the carbon content); natural grasslands and brushwoods account for 8.8%; the phytomass of wetlands (bogs and swamps), for 6.6%; and the phytomass of farmlands, for only 2.5%. Aboveground wood contains approximately two-thirds of the plant carbon (63.8%), and green parts contain 9.9%. For all classes of ecosystems, the proportion of underground phytomass averages 26.7% of the total amount, varying from 22.0% in forests to 57.1% in grasslands and brushwoods. The average phytomass density on lands covered with vegetation (1629.9 million hectares in Russia) is 5.02 kg/m² dry matter, or 2.45 kg C/m². The total amount of carbon in coarse woody debris is 4955 Tg C, and 9180 Tg C are in the underground necromass. In total, the vegetation of Russian terrestrial ecosystems (without litter) contains 54124 Tg carbon.     

Dynamics of carbon balance components in fallow arable lands on the Valdai Upland

The dynamics of carbon pools in the live phytomass, necromass, and soil reservoirs have been analyzed in fallow arable lands of Novgorod oblast. The results show that the amounts of above- and belowground necromass increase with the age of fallows, while the dynamics of live phytomass have no distinct trend. Comparisons with archival data show that the stocks of soil organic carbon in the studied ecosystems have decreased by 1.39 t C/ha since 1983, which is equivalent to an annual loss of 0.03 t C/ha. The main factors accounting for changes in the carbon stocks of fallow soils are the initial organic carbon contents in topsoil, the intensity of agromeliorative measures taken during the period of agricultural land use, and carbon contents in soils of meadow communities typical for a given region (zone).     

Aggregated Estimation of Basic Parameters of Biological Production and the Carbon Budget of Russian Terrestrial Ecosystems: 2. Net Primary Production

The estimated net primary production (NPP) of Russian terrestrial ecosystems (annual average over the period from 1988 to 1992) is 9544 Tg of dry matter, or 4353 Tg of carbon. Of the total amount, forests account for approximately 39.2% (here and below, comparisons are made with respect to carbon content); natural grasslands and brushwoods, for 27.6%; farmlands (arable land and cultivated pastures), for 22.0%; and wetlands, for 11.2%. The average NPP density on lands covered with vegetation (1629.8 million hectares in Russia) is 267 g C/m²per year. The highest value (498 g C/m²per year) is characteristic of arable lands. Other land-use/land-cover (LULC) classes have the following NPP densities (in areas covered with vegetation): grasslands and brushwoods, 278 g C/m²; forests, 224 g C/m²; and wetlands, 219 g C/m²per year. In general, Russian terrestrial ecosystems accumulate 59.7% of the total NPP in the aboveground phytomass (47.8% in green parts and 11.9% in wood) and 40.3% in the underground phytomass. The latter parameter differs significantly in different LULC classes and bioclimatic zones. According to calculations, the uncertainty in estimating the total NPP is 11% (a priori confidential probability 0.9).     

Dynamics of Carbon Pools and Fluxes in Russia's Forest Lands

The state and results of studies on the carbon cycle of forests on lands of the Russian forest fund (total area 1172 × 10⁶ ha) are analyzed at the federal level. Consideration is given to changes in the areas of different categories of forest lands, the age structure of stands, the pool and deposition of carbon in the phytomass, and the organic carbon pool of soils over the period from 1966 to 1998; the dynamics of activity in the forest industry by years and the extent of pyrogenic transformation of the forest cover between 1990 and 2001; and carbon fluxes associated with forest exploitation, including carbon emission resulting from fires.     

Sources and sinks of carbon dioxide in terrestrial ecosystems: Is the land's carbon budget balanced under the influence of man?

This contribution deals with the controversy between certain scientists on the role of terrestrial vegetation and soils in the global carbon cycle. The hypothesis of a significant net release from the vegetation, is rejected by geochemists because of the limited capacity of the ocean to take up this excess carbon dioxide. As for the man-influenced tropics, a comparison of the figures for the potential and the current phytomass, as well as plausible demographic arguments, support the assertion put forward by ecologists that the carbon budget of this zone cannot be balanced. The tropics lose about 1.7-3.9 × 10¹⁵ g/yr of carbon to the atmosphere; however, for several reasons, 0.5-2.8 × 10¹⁵ g/yr may be returned to land ecosystem, mostly in other climatic zones. Thus, a balance is achieved on combining low estimates for the losses with high estimates for the gains. From an ecological perspective, this solution is not a very probable one; nevertheless, it cannot conclusively be eliminated.     

Effect of fires on the functioning of phytocenoses of peat bogs in the Middle-Amur lowland

The dynamics and structure of the phytomass and production of an undisturbed mesotrophic dwarf shrub–sphagnum phytocenosis and one burned by fire have been compared. The net primary production (NPP) of both sites of phytocenoses in the postpyrogenic period is estimated by direct field determination of the productivity parameters, and C emission from the fire is assessed. The obtained data on emission (0.7 kg/m²) differ from the results obtained in the peatlands of western Canada (3.2 kg/m²).     

The Carbon Cycle in the Ecosystems of Thermal Springs in the Chukchi Peninsula as a Natural Model of Warming

Comparative studies on the ecosystems in the vicinity of thermal springs and in the typical tundra were performed in the southeastern Chukchi Peninsula in July and August 1997. Biogenic carbon fluxes during the greater part of the growing season were determined, the aboveground phytomass structure was studied, and the carbon reserve in the soil was estimated. It was demonstrated that the gross primary production and soil carbon in thermal ecosystems are greater than in similar permafrost ecosystems. The structural and ecophysiological changes leading to an increase in the gross production of plant communities were analyzed.     

Carbon cycle in spruce ecosystems of the northern Taiga subzone

The main components of the carbon balance have been determined in old spruce-bilberry forests of the northern taiga subzone. Annual carbon deposition in live phytomass and necromass has been determined by the weight method. Photosynthetic carbon binding has been calculated using the chlorophyll index, and the daily carbon balance has been estimated on the basis of direct measurements of CO₂ exchange. The results have shown that photosynthetic carbon binding by the phytocenosis amounts to 3.5–4 t/ha per year. Taking into consideration the litter yearly deposition decreased up to 1 t C/ha per year. With more than 70% of carbon accumulated in the organic mass being oxidized within the phytocenosis and returned to the atmosphere in the form of CO₂. Spruce ecosystems serve as a sink for 0.2–0.3 t C/ha per year.     

Organic carbon fluxes in the system soil-phytocenosis of bilberry-sphagnum spruce forest in the middle taiga zone of the Komi republic

Quantitative characteristics of organic carbon stock and distribution in the main ecosystem blocks and production-destruction processes in the soil-phytocenosis system have been evaluated in wet oldgrowth bilberry-sphagnum forest. It has been shown that equivalent amounts of carbon are accumulated in the soil and plant reservoirs of the ecosystem and that atmospheric carbon fixation for phytomass production prevails over carbon release in the course of necromass decomposition.     

Biological productivity of bogs in the middle taiga subzone of Western Siberia

New experimental data on biological productivity of plant communities in oligotrophic and mesotrophic bogs of the middle taiga subzone over the past five years are presented. The relationship between net primary production and the stock of live phytomass is estimated. The stock of necromass in oligotrophic bog ecosystems increases from west to east, while the stock of live phytomass and net primary production decrease.     

General analysis of forest vegetation in the south of the Far East with regard to the feeding of wild ruminants (Artiodactyla, Ruminantia)

Vegetation in the main types of forest landscapes in the south of the Far East has been analyzed with regard to the dependence of population density and spatial distribution of five wild ruminant species on the main parameters of phytomass. The results have shown that the majority of ruminant species at their current population density never suffer from insufficient food supply. A high population density of the sika deer (Cervus nippon) is the only factor that may cause degradation of vegetation in the study region. The present-day population density of ruminants in their habitats does not depend on the amount of phytomass and species diversity of forage plants. Conversely, there is a strong relationship between the highest population density of ruminants recorded during the past 50 years and the phytomass stock of forage plants in their habitats.     

Changes in the structure and phytomass of tree stands at the upper limit of their growth in the Southern Urals

Relationships between stem diameter and phytomass of trees and their parts (single- and multistemmed growth forms) have been studied at different altitudinal levels of the present-day upper treeline ecotone on the Iremel’ Massif, the Southern Urals. The time course of changes in the structure and phytomass of birch–spruce stands during the past centuries has been reconstructed. It is shown that the expansion of forests to the mountains in this period has occurred against the background of rise in summer and winter temperatures and increase in the amount of solid precipitation in the Southern Urals.     

Assessment of phytomass changes in an alpine <Emphasis Type="Italic">Geranium-Hedysarum</Emphasis> meadow after the removal of dominants: The results of a ten-year experiment

Changes in the aboveground phytomass of a Geranium-Hedysarum meadow community and its constituent species after the removal of dominants, Geranium gymnocaulon and Hedysarum caucasicum, over ten years have been studied in the Northwestern Caucasus. Responses of individual species to this intervention have been revealed. It has been shown that the phytomass of nondominant species increases under such conditions, but this cannot fully counterbalance the loss of phytomass resulting from the removal of dominants. Dominant species of Geranium-Hedysarum meadows exert different influences on the community structure and also compete with each other. However, this competition is fairly weak, which is probably due to considerable divergence of these species with respect to resource consumption.     

Characteristics of Carbon Storage and Density in Different Layers of Forest Ecosystems

Characteristics of carbon storage and density in different layers of forest ecosystems should be studied comprehensively and in more detail. Using forest inventory data in combination with field survey data, we explored the characteristics of carbon storage and density in different layers of forest ecosystems in Liaoning Province of China. Results showed that total carbon storage was 813.034 Tg C. The carbon storage of soil layer accounted for 81.0% of the total storage with 658.783 Tg C, followed by those of arbor, litter and shrub layers with 128.403 Tg C (15.8%), 22.723 Tg C (2.8%) and 3.125 Tg C (0.4%), respectively. The average carbon density for the forest ecosystems were 183.571 Mg C ha^–1, with soil layer (148.744 Mg C ha^–1) being the highest one, followed by arbor layer (28.992 Mg C ha^–1), litter layer (5.131 Mg C ha^–1) and shrub-grass layer (0.706 Mg C ha^–1). Carbon storage in different forest ecosystems varied from 1.595 to 319.161 Tg C, while C density ranged from 165.067 to 235.947Mg C ha^–1, with the highest and lowest values being observed in soil layer and shrub-grass layers, respectively, implying that soil is the main body of forest carbon storage. Young-aged forests accounted for a greater proportion of forests in the Province than forests in other age classes; and proper management of forests could increase the carbon sequestration in the forest ecosystems. The comparison with previous estimations of carbon storage for forest ecosystem implied that methods and data used for forest carbon storage estimation affected the results of estimates obviously.     

Changes in the structure of chortobiont invertebrate community exposed to emissions from a copper smelter

The aboveground phytomass of meadow plants and the density of chortobiont invertebrates in secondary upland meadows were estimated using a biocenometer in three areas differing in the level of pollution with emissions from the Middle Ural Copper Smelter (Revda, Sverdlovsk oblast) in 2006 and 2007. As the smelter is approached, the total amount of phytomass (dry weight) decreases by a factor of 1.3–1.9, with the proportion of grasses reaching 100%; the total abundance of invertebrates increases two-to threefold due to sucking phytophages, which account for up to 80% of the invertebrate community. The abundance of gnawing phytophages near the smelter is reduced, with some taxa entirely missing (e.g., mollusks and phalangiid harvestmen). Rearrangements in chortobiont community structure are attributable to changes in the physiological state of plants and in the species diversity and architecture of the herbaceous layer, with consequent modification of hydrothermal conditions in it, as well as by the direct toxic effect of heavy metals.     

Variations in bottom sediment nutrient and metal concentrations in the Genesee River watershed,New York

Variations in nutrient and metal concentrations of fluvial sediment may be due to varying combinations of natural and man-made factors: basin geology, surface erosion, riverbank erosion, industrial or other cultural contamination, the presence of minerals rich in trace elements (e.g. chromite), sediment ion-exchange capacity, sediment organic content, and the presence of metallic oxides. The data reported here were obtained in a study in New York State of sediment transport from the Genesee River watershed to Lake Ontario (6,500 km²; 2,400 sq.mi.). One hundred bottom sediment samples collected over a period of a year were chemically analyzed for aluminium, chromium, copper, iron, manganese, nickel, lead, zinc, total carbon, total organic carbon, total nitrogen, and phosphorus. The metal concentrations (arithmetic means ±S.D., in μg/g) were: Al, 6,660±2,620; Cr, 14±9; Cu, 18±7; Fe, 15,060±7,312; Mn, 424±212; Ni, 23±13; Pb, 40±67; and Zn, 69±37. For the major nutrients the results (mean ±1 S.D. in %) were: total carbon, 2.06 ± 1.68; total organic carbon, 1.37 ± 1.28; total nitrogen, 0.105 ± 0.098; and phosphorus, 0.0560 ± 0.014.     

Biocenotic self-regulation of productivity and quality of mixed agrocenoses with broadleaf herbs

Specific features of biocenotic self-regulation of productivity and phytomass quality in mixed agrocenoses with perennial broadleaf herbs in the mountain zone were analyzed experimentally. The dynamics of phytomass accumulation and decomposition and the course of succession were determined in an agrocenosis constructed on the model of plant communities typical for the mountain and piedmont zones of the Central Northern Caucasus.     

Aboveground phytomass and rate of plant debris decomposition in herbaceous communities exposed to soil pollution with heavy metals

Consideration is given to production and decomposition processes in herbaceous communities exposed to chemical pollution with heavy metals in the Middle Urals. High variation in the aboveground phytomass of agrobotanical groups (legumes, forbs, grasses) is due to spatial heterogeneity of soil pollution levels and consequent changes in the species composition of plant communities in the areas studied. Therefore, nonparametric statistical methods have been used (Kruskal–Wallis test with subsequent pairwise comparisons by Wilcoxon–Mann–Whitney with Bonferroni correction for multiple comparisons). The phytomass of legumes remains unchanged in the increasing pollution gradient, while the contribution of forbs to the total phytomass decreases and that of grasses increases. Soils rich in nutrient elements can maintain a high rate of plant debris decomposition, counterbalancing the adverse effect of increased heavy metal concentrations on relevant processes. The balance between production and mineralization processes provides for the sustainable, long-term existence of herbaceous communities under conditions of intense pollution of the natural environment.     

Agricultural GHG emission and calorie intake nexus among different socioeconomic households of rural eastern India

A study was conducted to examine the interrelationships among socioeconomic factors, household consumption patterns, calorie intake and greenhouse gas emissions factors in rural eastern India based on household survey data. Findings indicated that higher monthly per capita incomes (12.1–80.1$) were associated with greater average calorie intakes (2021–2525 kcal d^?1). As estimated by the FEEDME model, in total 17.2% of the population was calorie malnourished with a regional disparity of 29.4–18.2% malnourishment. Greenhouse gas (GHG) emissions were calculated only on the basis of crop and livestock production and consumption. Rice accounted for the highest share of total GHG emissions, on average 82.6% on a production basis, which varied from 58.1% to 94.9% in regional basis. Rice contributed the greatest share (~?65% and 66.2%) in terms of both calories and GHG emissions (CO₂ eq y^?1), respectively, on a consumption basis. We conclude that extensive rice farming and increasing animal product consumption are dominant factors in the higher carbon footprint in this region and are likely to further increase with increase in per capita income. This study provides useful information to help for better crop planning and for fine-tuning food access policy, to reduce carbon footprint and calorie malnutrition.