gesjGEOGRAPHY, ENVIRONMENT, SUSTAINABILITYGEOGRAPHY, ENVIRONMENT, SUSTAINABILITY2071-93882542-1565Russian Geographical Society10.24057/2071-9388-2024-3091gesj-3493Research ArticleRESEARCH PAPERСтатьиA regional-scale estimate of the soil organic carbon isotopic composition (δ13С) and its environmental drivers: case study of the Baikal regionGolubtsovViktor A.

Ulan-Batorskaya 1, Irkutsk, 664033 

tea_88@inbox.ruVanteevaYulia V.

Ulan-Batorskaya 1, Irkutsk, 664033 

CherkashinaAnna A.

Ulan-Batorskaya 1, Irkutsk, 664033 

V.B. Sochava Institute of Geography, Siberian Branch of Russian Academy of SciencesRussian Federation2024050720241727893Copyright © Golubtsov V., Vanteeva Y.V., Cherkashina A.A., 20242024Golubtsov V., Vanteeva Y.V., Cherkashina A.A.Golubtsov V., Vanteeva Y.V., Cherkashina A.A.Данная работа распространяется под лицензией Creative Commons Attribution 4.0.This work is licensed under a Creative Commons Attribution 4.0 License.https://ges.rgo.ru/jour/article/view/3493

Modern plants and surface soil δ13С values from 95 sites in the Baikal region were obtained for the first time and were used to establish relationships with regional environmental factors. Studied sites were distributed along the elevation gradient from 403 to 2315 m, which defined a strong landscape and climatic gradients encompassing mountain tundra, subalpine grasslands, mountain taiga, subtaiga, and steppe. δ13С values of soil organic matter (SOM) varied from –29.50 to –22.98‰. This result showed that the stable C isotopic composition of the surface soils was mainly determined by δ13С values of C3 plants (vary from –33.0 to –24.5‰) and C isotope fractionation during stabilization of plant-derived C into SOM. The δ13С values of modern plants and surface soils were negatively correlated with mean annual and growing season precipitation (p<0.05), confirming that precipitation is the primary factor determining SOM’s stable C isotopic composition in the Baikal region. A distinct increase in the δ13С values with decreasing mean annual and growing season precipitation was found with a slope of –0.42‰/100 mm and –0.97‰/100 mm, respectively. Temperature had no significant effect on the spatial distribution of SOM δ13С values at the regional scale but played an important role in the severe environments of mountain tundra (the coldest and wettest) and steppes (the warmest and driest). Such conditions strongly impacted SOM δ13С values by influencing plant species composition and soil microbiological activity. As a result, the organic matter of these soils is characterized by the highest δ13С values. The SOM of taiga soils formed under a favorable combination of temperature and precipitation was characterized by the lowest δ13С values

carbonδ13СC3 plantsclimatic conditionsmountain areasSoutheastern SiberiaThe work was supported by the state assignment АААА-А21-121012190055-7 (FWEM-2021-0002), АААА-А21-121012190056-4. We are grateful to E.P. Zazovskaya and S.M. Turchinskaya, who kindly organized the laboratory work and stable isotopic measurements. Further special thanks to N.N. Voropay, E.A. Dukarev, M.Yu. Opekunova, M.A. Bronnikova, and T.I. Znamenskaya, who valuably supported us during the fieldwork.ReferencesAbasheeva N.E. (1992). Agrochemistry of soils of Transbaikalia. Nowosibirsk: Nauka (in Russian).Abasheeva N.E. (1992). Agrochemistry of soils of Transbaikalia. Nowosibirsk: Nauka (in Russian).Andreeva D.B., Balsanova L.D., Lavrent’eva I.N., Gonchikov B.N., Tsybikdorzhiev V.Ts., Glaser B. and Zech W. (2022). Variations in carbon and nitrogen isotopes in soils along the Barguzinsky Ridge, Eastern Baikal Region, Russia. Moscow Univ. Soil Sci. Bull, 77, 277–283, DOI: 10.3103/S0147687422040020.Andreeva D.B., Balsanova L.D., Lavrent’eva I.N., Gonchikov B.N., Tsybikdorzhiev V.Ts., Glaser B. and Zech W. (2022). Variations in carbon and nitrogen isotopes in soils along the Barguzinsky Ridge, Eastern Baikal Region, Russia. Moscow Univ. Soil Sci. Bull, 77, 277–283, DOI: 10.3103/S0147687422040020.Andreeva D., Zech M., Glaser B., Erbajeva M., Chimitdorgieva G., Ermakova O. and Zech W. (2013). Stable isotope (δ13C, δ15N, δ18O) record of soils in Buryatia, southern Siberia: Implications for biogeochemical and paleoclimatic interpretations. Quaternary International, 290–291, 82–94, DOI: 10.1016/j.quaint.2012.10.054.Andreeva D., Zech M., Glaser B., Erbajeva M., Chimitdorgieva G., Ermakova O. and Zech W. (2013). Stable isotope (δ13C, δ15N, δ18O) record of soils in Buryatia, southern Siberia: Implications for biogeochemical and paleoclimatic interpretations. Quaternary International, 290–291, 82–94, DOI: 10.1016/j.quaint.2012.10.054.Belov A.V., Bezrukova E.V. and Sokolova L.P. (2018). The evolutionary-genetic basis of structural-cenotic diversity of modern vegetation in Prebaikalia. Geography and Natural Resources, 39(1), 46–54, DOI: 10.1134/S1875372818010079.Belov A.V., Bezrukova E.V. and Sokolova L.P. (2018). The evolutionary-genetic basis of structural-cenotic diversity of modern vegetation in Prebaikalia. Geography and Natural Resources, 39(1), 46–54, DOI: 10.1134/S1875372818010079.Budyko M.I. (1971). Climate and life. Leningrad: Gidrometeoizdat (in Russian).Budyko M.I. (1971). Climate and life. Leningrad: Gidrometeoizdat (in Russian).Byazrov L.G., Gongalsky K.B., Pelgunova L.A. and Tiunov A.V. (2010). Carbon isotope composition (δ13C) of lichen thalli in forests near the Chernobyl nuclear power plant. Radiation Biology. Radioecology, 50 (1), 98-105 (in Russian).Byazrov L.G., Gongalsky K.B., Pelgunova L.A. and Tiunov A.V. (2010). Carbon isotope composition (δ13C) of lichen thalli in forests near the Chernobyl nuclear power plant. Radiation Biology. Radioecology, 50 (1), 98-105 (in Russian).Cernusak L.A., Ubierna N., Winter K., Holtum J.A., Marshall J.D. and Farquhar G.D. (2013). Environmental and physiological determinants of carbon isotope discrimination in terrestrial plants. New Phytol, 200, 950–965, DOI: 10.1111/nph.12423.Cernusak L.A., Ubierna N., Winter K., Holtum J.A., Marshall J.D. and Farquhar G.D. (2013). Environmental and physiological determinants of carbon isotope discrimination in terrestrial plants. New Phytol, 200, 950–965, DOI: 10.1111/nph.12423.Chen Y., Lu H., Zhang E., Zhang H., Xu Z., Yi S. and Wu S.-E. (2015). Test stable carbon isotopic composition of soil organic matters as a proxy indicator of past precipitation: Study of the and fields in northern China. Quaternary International, 372, 79–86, DOI: 10.1016/j.quaint.2014.10.062.Chen Y., Lu H., Zhang E., Zhang H., Xu Z., Yi S. and Wu S.-E. (2015). Test stable carbon isotopic composition of soil organic matters as a proxy indicator of past precipitation: Study of the and fields in northern China. Quaternary International, 372, 79–86, DOI: 10.1016/j.quaint.2014.10.062.Chimitdorzhieva G.D. (2016). Organic matter of cold soils. Ulan-Ude: Buryat Scientific Centre SB RAS (in Russian).Chimitdorzhieva G.D. (2016). Organic matter of cold soils. Ulan-Ude: Buryat Scientific Centre SB RAS (in Russian).Cornwell W.K., Wright I.J., Turner J., Maire V., Barbour M.M., Cernusak L.A., Dawson T., Ellsworth D., Farquhar G.D., Griffiths H., Keitel C., Knohl A., Reich P.B., Williams D.G., Bhaskar R., Cornelissen J.H.C., Richards A., Schmidt S., Valladares F., Körner C., Schulze E.-D., Buchmann N. and Santiago L.S. (2018). Climate and soils together regulate photosynthetic carbon isotope discrimination within C3 plants worldwide. Global Ecol. Biogeogr, 27, 1056-1067, DOI: 10.1111/geb.12764.Cornwell W.K., Wright I.J., Turner J., Maire V., Barbour M.M., Cernusak L.A., Dawson T., Ellsworth D., Farquhar G.D., Griffiths H., Keitel C., Knohl A., Reich P.B., Williams D.G., Bhaskar R., Cornelissen J.H.C., Richards A., Schmidt S., Valladares F., Körner C., Schulze E.-D., Buchmann N. and Santiago L.S. (2018). Climate and soils together regulate photosynthetic carbon isotope discrimination within C3 plants worldwide. Global Ecol. Biogeogr, 27, 1056-1067, DOI: 10.1111/geb.12764.Dawson T.E., Mambelli S., Plamboeck A.H., Templer P.H. and Tu K.P. (2002). Stable isotopes in plant ecology. Annual Reviews of Ecology and Systematics, 33, 507–559, DOI: 10.1146/annurev.ecolsys.33.020602.095451.Dawson T.E., Mambelli S., Plamboeck A.H., Templer P.H. and Tu K.P. (2002). Stable isotopes in plant ecology. Annual Reviews of Ecology and Systematics, 33, 507–559, DOI: 10.1146/annurev.ecolsys.33.020602.095451.Diefendorf A.F., Mueller K.E., Wing S.L., Koch P.L. and Freeman K.H. (2010). Global patterns in leaf 13C discrimination and implications for studies of past and future climate. PNAS, 107, 5738–5743, DOI: 10.1073/pnas.0910513107.Diefendorf A.F., Mueller K.E., Wing S.L., Koch P.L. and Freeman K.H. (2010). Global patterns in leaf 13C discrimination and implications for studies of past and future climate. PNAS, 107, 5738–5743, DOI: 10.1073/pnas.0910513107.Ehleringer J.R. (2005). The influence of atmospheric CO2, temperature, and water on the abundance of C3/C4 taxa. In: I. Baldwin, ed., A history of atmospheric CO2 and its effects on plants, animals and ecosystems. Ecological Studies. New York: Springer, 214-231, DOI: 10.1007/0-387-27048-5_10.Ehleringer J.R. (2005). The influence of atmospheric CO2, temperature, and water on the abundance of C3/C4 taxa. In: I. Baldwin, ed., A history of atmospheric CO2 and its effects on plants, animals and ecosystems. Ecological Studies. New York: Springer, 214-231, DOI: 10.1007/0-387-27048-5_10.Farquhar G.D., Ehleringer J.R. and Hubick K.T. (1989). Carbon isotope discrimination and photosynthesis. Ann. Rev. Plant Physiol. Plant Molecul. Biol, 40, 503–537.Farquhar G.D., Ehleringer J.R. and Hubick K.T. (1989). Carbon isotope discrimination and photosynthesis. Ann. Rev. Plant Physiol. Plant Molecul. Biol, 40, 503–537.Feng Z.D., Wang L.X., Ji Y.H., Guo L.L., Lee X.Q. and Dworkin S.I. (2008). Climatic dependency of soil organic carbon isotopic composition along the S-N Transect from 34°N to 52°N in central-east Asia. Palaeogeography Palaeoclimatology Palaeoecology, 257, 335–343, DOI: 10.1016/j.palaeo.2007.10.026.Feng Z.D., Wang L.X., Ji Y.H., Guo L.L., Lee X.Q. and Dworkin S.I. (2008). Climatic dependency of soil organic carbon isotopic composition along the S-N Transect from 34°N to 52°N in central-east Asia. Palaeogeography Palaeoclimatology Palaeoecology, 257, 335–343, DOI: 10.1016/j.palaeo.2007.10.026.Fick S.E. and Hijmans R.J. (2017). WorldClim 2: New 1-km spatial resolution climate surfaces for global land areas. International Journal of Climatology, 37(2), DOI: 10.1002/joc.5086.Fick S.E. and Hijmans R.J. (2017). WorldClim 2: New 1-km spatial resolution climate surfaces for global land areas. International Journal of Climatology, 37(2), DOI: 10.1002/joc.5086.Golubtsov V.A. (2020). Stable carbon isotopic composition of organic matter of the Late Pleistocene and Holocene soils of the Baikal Region. Eurasian Soil Science, 53(6), 724-738, DOI: 10.1134/S1064229320060046.Golubtsov V.A. (2020). Stable carbon isotopic composition of organic matter of the Late Pleistocene and Holocene soils of the Baikal Region. Eurasian Soil Science, 53(6), 724-738, DOI: 10.1134/S1064229320060046.Golubtsov V.A., Cherkashina A.A., Vanteeva Yu.V., Voropai N.N. and Turchinskaya S.M. (2023b). Variations in stable carbon isotopic composition of soil organic matter in mountain depressions of the Cis-Baikal region. Contemporary problems of ecology, 16(6), 776-789. DOI: 10.1134/S1995425523060094.Golubtsov V.A., Cherkashina A.A., Vanteeva Yu.V., Voropai N.N. and Turchinskaya S.M. (2023b). Variations in stable carbon isotopic composition of soil organic matter in mountain depressions of the Cis-Baikal region. Contemporary problems of ecology, 16(6), 776-789. DOI: 10.1134/S1995425523060094.Golubtsov V.A., Vanteeva Yu.V., Bronnikova M.A., Cherkashina A.A. and Znamenskaya T.I. (2023a). Composition of stable carbon isotopes in organic matter of Cambisols of the Eastern Sayan foothills. Eurasian Soil Science, 56(2), 184-202, DOI: 10.1134/S1064229322602049.Golubtsov V.A., Vanteeva Yu.V., Bronnikova M.A., Cherkashina A.A. and Znamenskaya T.I. (2023a). Composition of stable carbon isotopes in organic matter of Cambisols of the Eastern Sayan foothills. Eurasian Soil Science, 56(2), 184-202, DOI: 10.1134/S1064229322602049.Golubtsov V.A., Vanteeva Yu.V. and Voropay N.N. (2021). Effect of humidity on the stable carbon isotopic composition of soil organic matter in the Baikal region. Eurasian Soil Science, 54(10), 1463-1474, DOI: 10.1134/S1064229321100069.Golubtsov V.A., Vanteeva Yu.V. and Voropay N.N. (2021). Effect of humidity on the stable carbon isotopic composition of soil organic matter in the Baikal region. Eurasian Soil Science, 54(10), 1463-1474, DOI: 10.1134/S1064229321100069.Golubtsov V.A., Vanteeva Yu.V., Voropai N.N., Vasilenko O.V., Cherkashina A.A. and Zazovskaya E.P. (2022). Stable carbon isotopic composition (δ13C) as a proxy of organic matter dynamics in soils on the western shore of Lake Baikal. Eurasian Soil Science, 55(12), 1688- 1701, DOI: 10.1134/S1064229322700041.Golubtsov V.A., Vanteeva Yu.V., Voropai N.N., Vasilenko O.V., Cherkashina A.A. and Zazovskaya E.P. (2022). Stable carbon isotopic composition (δ13C) as a proxy of organic matter dynamics in soils on the western shore of Lake Baikal. Eurasian Soil Science, 55(12), 1688- 1701, DOI: 10.1134/S1064229322700041.Hammer O., Harper D.A. and Ryan P.D. (2001). Past: Paleontological Statistics Software Package for Education and Data Analysis. Palaeontologia Electronica, 4(1), 4.Hammer O., Harper D.A. and Ryan P.D. (2001). Past: Paleontological Statistics Software Package for Education and Data Analysis. Palaeontologia Electronica, 4(1), 4.Highlands of the Fore-Baikal region and Transbaikalia (1974). Moscow: Nauka (in Russian).Highlands of the Fore-Baikal region and Transbaikalia (1974). Moscow: Nauka (in Russian).IUSS Working Group WRB. World Reference Base for Soil Resources, 2015. International soil classification system for naming soils and creating legends for soil maps. World Soil Resources Reports. № 106. Rome.IUSS Working Group WRB. World Reference Base for Soil Resources, 2015. International soil classification system for naming soils and creating legends for soil maps. World Soil Resources Reports. № 106. Rome.Ivanova L.I., Ivanov L.A., Ronzhina D.A., Yudina P.K., Migalina S.V., Shinehuu T., Tserenkhand G., Voronin P.Yu., Anenkhonov O.A., Bazha S.N. and Gunin P.D. (2019). Leaf traits of C3- and C4-plants indicating climatic adaptation along latitudinal gradient in Southern Siberia and Mongolia. Flora, 254, 122-134, DOI: 10.1016/j.flora.2018.10.008.Ivanova L.I., Ivanov L.A., Ronzhina D.A., Yudina P.K., Migalina S.V., Shinehuu T., Tserenkhand G., Voronin P.Yu., Anenkhonov O.A., Bazha S.N. and Gunin P.D. (2019). Leaf traits of C3- and C4-plants indicating climatic adaptation along latitudinal gradient in Southern Siberia and Mongolia. Flora, 254, 122-134, DOI: 10.1016/j.flora.2018.10.008.Jia Y., Wang G., Tan Q. and Chen Z. (2016). Temperature exerts no influence on organic matter δ13C of surface soil along the 400mm isopleth of mean annual precipitation in China. Biogeosciences, 13, 5057–5064, DOI: 10.5194/bg-13-5057-2016.Jia Y., Wang G., Tan Q. and Chen Z. (2016). Temperature exerts no influence on organic matter δ13C of surface soil along the 400mm isopleth of mean annual precipitation in China. Biogeosciences, 13, 5057–5064, DOI: 10.5194/bg-13-5057-2016.Kohn M.J. (2010). Carbon isotope compositions of terrestrial C3 plants as indicators of (paleo)ecology and (paleo)climate. PNAS, 107, 19691–19695, DOI: 10.1073/pnas.1004933107.Kohn M.J. (2010). Carbon isotope compositions of terrestrial C3 plants as indicators of (paleo)ecology and (paleo)climate. PNAS, 107, 19691–19695, DOI: 10.1073/pnas.1004933107.Koposov G.F. (1983). Genesis of mountain soils of Cisbaikalia. Nowosibirsk: Nauka (in Russian).Koposov G.F. (1983). Genesis of mountain soils of Cisbaikalia. Nowosibirsk: Nauka (in Russian).Kudeyarov V.N., Zavarzin G.A., Blagodatsky S.A., Borisov A.V., Voronin P.Yu., Demkin V.A., Demkina T.S., Evdokimov I.V., Zamolodchikov D.G., Karelin D.V., Komarov A.S., Kurganova I.N., Larionova A.A., Lopes de Gereny V.O., Utkin A.I. and Chertov O.G. (2007). Carbon pools and fluxes in terrestrial ecosystems of Russia. Moscow: Nauka (in Russian).Kudeyarov V.N., Zavarzin G.A., Blagodatsky S.A., Borisov A.V., Voronin P.Yu., Demkin V.A., Demkina T.S., Evdokimov I.V., Zamolodchikov D.G., Karelin D.V., Komarov A.S., Kurganova I.N., Larionova A.A., Lopes de Gereny V.O., Utkin A.I. and Chertov O.G. (2007). Carbon pools and fluxes in terrestrial ecosystems of Russia. Moscow: Nauka (in Russian).Kuz’min V.A. (1988). Soils of Cisbaikalia and Northern Transbaikalia. Nowosibirsk: Nauka (in Russian).Kuz’min V.A. (1988). Soils of Cisbaikalia and Northern Transbaikalia. Nowosibirsk: Nauka (in Russian).Kuznetsova A.O., Ivanova A.A., Slagoda E.A. and Tikhonravova Ya.V. (2020). Stable carbon isotopes in modern plants of the tracts of the key area of Marre-Sale (Western Yamal). Arctic and Antarctic, 1, 57-74, DOI: 10.7256/2453-8922.2020.1.32204 (in Russian).Kuznetsova A.O., Ivanova A.A., Slagoda E.A. and Tikhonravova Ya.V. (2020). Stable carbon isotopes in modern plants of the tracts of the key area of Marre-Sale (Western Yamal). Arctic and Antarctic, 1, 57-74, DOI: 10.7256/2453-8922.2020.1.32204 (in Russian).Lee X., Feng Z., Guo L., Wang L., Jin L., Huang Y., Chopping M., Huang D., Jiang W., Jiang Q. and Cheng H. (2005). Carbon isotope of bulk organic matter: A proxy for precipitation in the arid and semiarid central East Asia. Global Biochem. Cycles, 19, GB4010, DOI: 10.1029/2004GB002303.Lee X., Feng Z., Guo L., Wang L., Jin L., Huang Y., Chopping M., Huang D., Jiang W., Jiang Q. and Cheng H. (2005). Carbon isotope of bulk organic matter: A proxy for precipitation in the arid and semiarid central East Asia. Global Biochem. Cycles, 19, GB4010, DOI: 10.1029/2004GB002303.Mackay A.W., Seddon A., Leng M.J., Heumann G., Morley D.W., Piotrowska N., Rioual P., Roberts S. and Swann G. (2016). Holocene carbon dynamics at the forest–steppe ecotone of southern Siberia. Global Change Biology, 23(5), DOI: 10.1111/gcb.13583.Mackay A.W., Seddon A., Leng M.J., Heumann G., Morley D.W., Piotrowska N., Rioual P., Roberts S. and Swann G. (2016). Holocene carbon dynamics at the forest–steppe ecotone of southern Siberia. Global Change Biology, 23(5), DOI: 10.1111/gcb.13583.Menyailo O.V. and Hungate B.A. (2006). Carbon and nitrogen stable isotopes in forest soils of Siberia. Doklady Earth Sciences, 409(5), 747–749, DOI: 10.1134/S1028334X06050151.Menyailo O.V. and Hungate B.A. (2006). Carbon and nitrogen stable isotopes in forest soils of Siberia. Doklady Earth Sciences, 409(5), 747–749, DOI: 10.1134/S1028334X06050151.Mikheev V.S. and Ryashin V.A. (1977). Landscapes of the south of Eastern Siberia. Moscow: GUGK (in Russian).Mikheev V.S. and Ryashin V.A. (1977). Landscapes of the south of Eastern Siberia. Moscow: GUGK (in Russian).Muñoz Sabater J. (2019). ERA5-Land hourly data from 1981 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS), DOI: 10.24381/cds.e2161bac.Muñoz Sabater J. (2019). ERA5-Land hourly data from 1981 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS), DOI: 10.24381/cds.e2161bac.O’Leary M.H. (1988). Carbon isotope in photosynthesis. Bioscience, 38, 328-336.O’Leary M.H. (1988). Carbon isotope in photosynthesis. Bioscience, 38, 328-336.Pepin N.C. and Lundquist J.D. (2008). Temperature trends at high elevations: patterns across the globe. Geophys. Res. Lett, 35(14), L14701, DOI: 10.1029/2008GL034026.Pepin N.C. and Lundquist J.D. (2008). Temperature trends at high elevations: patterns across the globe. Geophys. Res. Lett, 35(14), L14701, DOI: 10.1029/2008GL034026.Plateaus and lowlands of Eastern Siberia (1971). Moscow: Nauka (in Russian).Plateaus and lowlands of Eastern Siberia (1971). Moscow: Nauka (in Russian).Plyusnin V.M., Bilichenko I.N. and Sedykh S.A. (2018). Spatio-temporal organization of mountain taiga geosystems of the Baikal natural territory. Geography and natural resources, 39, 130-139, DOI: 10.1134/S1875372818020051.Plyusnin V.M., Bilichenko I.N. and Sedykh S.A. (2018). Spatio-temporal organization of mountain taiga geosystems of the Baikal natural territory. Geography and natural resources, 39, 130-139, DOI: 10.1134/S1875372818020051.Rao Z., Guo W., Cao J., Shi F., Jiang H. and Li C. (2017). Relationship between the stable carbon isotopic composition of modern plants and surface soils and climate: A global review. Earth-Science Reviews, 165, 110–119, DOI: 10.1016/j.earscirev.2016.12.007.Rao Z., Guo W., Cao J., Shi F., Jiang H. and Li C. (2017). Relationship between the stable carbon isotopic composition of modern plants and surface soils and climate: A global review. Earth-Science Reviews, 165, 110–119, DOI: 10.1016/j.earscirev.2016.12.007.Sage R.F. (2005). Atmospheric CO2, environmental stress and the evolution of C4 photosynthesis. In: I. Baldwin, ed., A history of atmospheric CO2 and its effects on plants, animals and ecosystems. Ecological Studies. 177. New York: Springer, 185-213, DOI: 10.1007/0-387-27048-5_9.Sage R.F. (2005). Atmospheric CO2, environmental stress and the evolution of C4 photosynthesis. In: I. Baldwin, ed., A history of atmospheric CO2 and its effects on plants, animals and ecosystems. Ecological Studies. 177. New York: Springer, 185-213, DOI: 10.1007/0-387-27048-5_9.Schepaschenko D.G., Shvidenko A.Z., Mukhortova L.V. and Vedrova E.F. (2013). The pool of organic carbon in the soils of Russia. Eurasian Soil Science, 46(2), 107-116, DOI: 10.1134/S1064229313020129.Schepaschenko D.G., Shvidenko A.Z., Mukhortova L.V. and Vedrova E.F. (2013). The pool of organic carbon in the soils of Russia. Eurasian Soil Science, 46(2), 107-116, DOI: 10.1134/S1064229313020129.Scientific and applied handbook on the climate of the USSR (1989). Long-term data. Series 3. Part 1-6. Issue 23. Buryat ASSR, Chita region. Leningrad: Gidrometeoizdat (in Russian).Scientific and applied handbook on the climate of the USSR (1989). Long-term data. Series 3. Part 1-6. Issue 23. Buryat ASSR, Chita region. Leningrad: Gidrometeoizdat (in Russian).Scientific and applied handbook on the climate of the USSR (1991). Long-term data. Series 3. Part 1-6. Issue 22. Irkutsk region and western part of Buryat ASSR. Leningrad: Gidrometeoizdat (in Russian).Scientific and applied handbook on the climate of the USSR (1991). Long-term data. Series 3. Part 1-6. Issue 22. Irkutsk region and western part of Buryat ASSR. Leningrad: Gidrometeoizdat (in Russian).Shimaraev M.N., Kuimova K.N., Sinyukovich V.N. and Tsekhanovskii V.V. (2002). Manifestation of global climatic changes in Lake Baikal during the 20th century. Doklady Earth Sciences, 383(3), 288-291.Shimaraev M.N., Kuimova K.N., Sinyukovich V.N. and Tsekhanovskii V.V. (2002). Manifestation of global climatic changes in Lake Baikal during the 20th century. Doklady Earth Sciences, 383(3), 288-291.Tiunov A.V. (2007). Stable isotopes of carbon and nitrogen in soil ecological studies. Biology bulletin, 34 (4), 395-407. DOI: 10.1134/S1062359007040127.Tiunov A.V. (2007). Stable isotopes of carbon and nitrogen in soil ecological studies. Biology bulletin, 34 (4), 395-407. DOI: 10.1134/S1062359007040127.Trofimova I.E., Osipova O.P. and Balybina A.A. (2019). Approaches to evaluating climate and ecological resources of Siberia. Contemporary problems of Ecology, 12(5), 444-452. DOI: 10.1134/S1995425519050111.Trofimova I.E., Osipova O.P. and Balybina A.A. (2019). Approaches to evaluating climate and ecological resources of Siberia. Contemporary problems of Ecology, 12(5), 444-452. DOI: 10.1134/S1995425519050111.Tsybenov Y.B., Chimitdorzhieva G.D., Egorova R.A. and Gongal’skii K.B. (2016). The pool of organic carbon and its isotopic composition in cryomorphic quasi-gley chernozems of the Transbaikal region. Eurasian Soil Science, 49(1), 8-14, DOI: 10.1134/S106422931507011X.Tsybenov Y.B., Chimitdorzhieva G.D., Egorova R.A. and Gongal’skii K.B. (2016). The pool of organic carbon and its isotopic composition in cryomorphic quasi-gley chernozems of the Transbaikal region. Eurasian Soil Science, 49(1), 8-14, DOI: 10.1134/S106422931507011X.Tsybenov Y.B., Chimitdorzhieva G.D., Egorova R.A. and Milkheev E.Yu. (2022). Isotope composition of carbon of plants and organic matter in Burozems of the southern Vitim Plateau. Moscow Univ. Soil Sci. Bull, 77, 266-270, DOI: 10.3103/S0147687422040135.Tsybenov Y.B., Chimitdorzhieva G.D., Egorova R.A. and Milkheev E.Yu. (2022). Isotope composition of carbon of plants and organic matter in Burozems of the southern Vitim Plateau. Moscow Univ. Soil Sci. Bull, 77, 266-270, DOI: 10.3103/S0147687422040135.Volkovintser V.I. (1978). Steppe cryoaridic soils. Nowosibirsk: Nauka (in Russian).Volkovintser V.I. (1978). Steppe cryoaridic soils. Nowosibirsk: Nauka (in Russian).Wang G.A., Li J.Z., Liu X.Z. and Li X.Y. (2013). Variations in carbon isotope ratios of plants across a temperature gradient along the 400 mm isoline of mean annual precipitation in north China and their relevance to paleovegetation reconstruction. Quaternary Science Reviews, 63, 83-90, DOI: 10.1016/j.quascirev.2012.12.004.Wang G.A., Li J.Z., Liu X.Z. and Li X.Y. (2013). Variations in carbon isotope ratios of plants across a temperature gradient along the 400 mm isoline of mean annual precipitation in north China and their relevance to paleovegetation reconstruction. Quaternary Science Reviews, 63, 83-90, DOI: 10.1016/j.quascirev.2012.12.004.Xu M., Wang G., Li X., Cai X., Li X., Christie P. and Zhang J. (2015). The key factor limiting plant growth in cold and humid alpine areas also plays a dominant role in plant carbon isotope discrimination. Frontiers in Plant Science, 6, 961, DOI: 10.3389/fpls.2015.00961.Xu M., Wang G., Li X., Cai X., Li X., Christie P. and Zhang J. (2015). The key factor limiting plant growth in cold and humid alpine areas also plays a dominant role in plant carbon isotope discrimination. Frontiers in Plant Science, 6, 961, DOI: 10.3389/fpls.2015.00961.Zhang D., Yang Y. and Ran M. (2020). Variations of surface soil δ13Corg in the different climatic regions of China and paleoclimatic implication. Quaternary International, 536, 92–102, DOI: 10.1016/j.quaint.2019.12.015.Zhang D., Yang Y. and Ran M. (2020). Variations of surface soil δ13Corg in the different climatic regions of China and paleoclimatic implication. Quaternary International, 536, 92–102, DOI: 10.1016/j.quaint.2019.12.015.Zhao Y., Wu F., Fang X. and Yang Y. (2017). Altitudinal variations in the bulk organic carbon isotopic composition of topsoil in the Qilian Mountains area, NE Tibetan Plateau, and its environmental significance. Quaternary International, 454, 45-55, DOI: 10.1016/ j.quaint.2017.08.045.Zhao Y., Wu F., Fang X. and Yang Y. (2017). Altitudinal variations in the bulk organic carbon isotopic composition of topsoil in the Qilian Mountains area, NE Tibetan Plateau, and its environmental significance. Quaternary International, 454, 45-55, DOI: 10.1016/ j.quaint.2017.08.045.Zhukov V.M. (1965). Climate. In: I.P. Gerasimov, ed., Fore-Baikal region and Transbaikalia. Moscow: Nauka, 91-127 (in Russian).Zhukov V.M. (1965). Climate. In: I.P. Gerasimov, ed., Fore-Baikal region and Transbaikalia. Moscow: Nauka, 91-127 (in Russian).

The authors declare that there are no conflicts of interest present.