Key periods of peatland development and environmental changes in the middle taiga zone of Western Siberia during the Holocene

AMBIO ◽  
2021 ◽  
Author(s):  
Andrey N. Tsyganov ◽  
Evgeny A. Zarov ◽  
Yuri A. Mazei ◽  
Mikhail G. Kulkov ◽  
Kirill V. Babeshko ◽  
...  
The Holocene ◽  
2021 ◽  
pp. 095968362097279
Author(s):  
Kirill V Babeshko ◽  
Anna Shkurko ◽  
Andrey N Tsyganov ◽  
Elena E Severova ◽  
Mariusz Gałka ◽  
...  

A better understanding of past long-term environmental changes in the subarctic region is crucial for mitigation of the possible negative effects of climate warming in this vulnerable region. This study provides a new multi-proxy reconstruction of regional vegetation changes and peatland development for north-eastern Fennoscandia (Russia) during most of the Holocene. To that purpose, we performed plant macrofossil, pollen, testate amoebae, peat humification, loss on ignition and radiocarbon analyses of the peat deposits from a mire around Vodoprovodnoe Lake (the Kindo Peninsula, the Republic of Karelia). Our data indicate that the peat deposits started accumulating before 9147 ± 182 cal. yr. BP. The vegetation cover in the area was mainly typical for the northern taiga zone, except for the period ~7800–5600 cal. yr. BP, when it generally resembled the middle taiga zone. The vegetation cover and peatland were greatly affected by reoccurring fires, which can be partly related to human activity. These events were associated with an increased proportion of birch in the vegetation cover (as a pioneer species) and/or water level decreases. By 600 cal. yr. BP, the peatland and the surrounding vegetation reached its current state and only minor changes had been recorded since that time. Overall, our results suggest a considerable and unexpected role of fires in the postglacial dynamics of subarctic peatlands.


2021 ◽  
Author(s):  
Alina Kurasova ◽  
Alexandr Konstantinov ◽  
Sergey Loiko ◽  
Sergey Kulizhskiy

<p>The activities of ancient population strongly affected the development of landscapes and soils in Western Siberia during the late Holocene. It should be noted that studies devoted to the processes of natural and anthropogenic evolution within this vast territory are extremely irregular. Thus, the significant proportion of the materials on the dynamic of Siberian landscapes in the Holocene, related to the studies of various natural archives and archeological monuments, falls on the southern part of region. On the one hand, this situation is due to the relatively recent development of Western Siberia in relation to the development of hydrocarbon deposits, on the other hand, on the peculiarities of the relief and landscapes prevailing in the central and northern parts of the West Siberian Plain. A significant part of the territory under consideration is characterized by low, poorly dissected relief, which largely contributes to its bogging and widespread distribution of organogenic peat soils. It is not surprising that the deposits of lakes and peat bogs are the main natural archives that provide information on the dynamics of the natural environment within the central parts of Western Siberia and, first of all, the taiga zone, while the potential of mineral soils and sediments from this point of view is insignificant, compared to other regions. At the same time the boreal zone of Western Siberia is very large and includes regions with more complex geomorphological conditions.</p><p>To assess the possibility of using buried soils and colluvial layers in the middle taiga of Western Siberia for reconstruction of the Holocene landscape’s dynamics, we carried out research on two key sites with rather contrast relief and high frequency of archeological sites: in the middle Yugan River Basin and in the North of the Kondinskaya Lowland. Buried soils and colluvial sediments in a number of sections characterizing foots of the steep slopes on the border with peat bogs were selected as objects for our study. Based on the obtained radiocarbon dates it is possible to preliminarily identify several stages of the activation of erosional processes. For the north of the Kondinskaya lowland three remarkable phases of erosional activity were identified, while for the Yugan River Basin the number of phases was larger - 6. It is interesting to note that the obtained results make it possible to correlate these two regions. The presence of a larger number of recorded erosion-pyrogenic events for the Yugan River basin reflects a longer permanent human presence in the area under consideration, which is also consistent with archaeological data.</p><p>The study was funded by the Ministry of Science and Higher Education of the Russian Federation and was performed as a part of project FEWZ-2020-0007 “Fundamentals of the natural environment history of the south of Western Siberia and Turgay in the Cenozoic: sequence sedimentology, abiotic geological events and the evolution of the Paleobiosphere“. The studies were carried out using the equipment of the Center for Collective Use "Bioinert Systems of the Cryosphere", Tyumen Scientific Center, SB RAS and RFBR, project number 20-04-00836.</p>


Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 824
Author(s):  
Egor Dyukarev ◽  
Evgeny Zarov ◽  
Pavel Alekseychik ◽  
Jelmer Nijp ◽  
Nina Filippova ◽  
...  

The peatlands of the West Siberian Lowlands, comprising the largest pristine peatland area of the world, have not previously been covered by continuous measurement and monitoring programs. The response of peatlands to climate change occurs over several decades. This paper summarizes the results of peatland carbon balance studies collected over ten years at the Mukhrino field station (Mukhrino FS, MFS) operating in the Middle Taiga Zone of Western Siberia. A multiscale approach was applied for the investigations of peatland carbon cycling. Carbon dioxide fluxes at the local scale studied using the chamber method showed net accumulation with rates from 110, to 57.8 gC m−2 at the Sphagnum hollow site. Net CO2 fluxes at the pine-dwarf shrubs-Sphagnum ridge varied from negative (−32.1 gC m−2 in 2019) to positive (13.4 gC m−2 in 2017). The cumulative May-August net ecosystem exchange (NEE) from eddy-covariance (EC) measurements at the ecosystem scale was −202 gC m−2 in 2015, due to the impact of photosynthesis of pine trees which was not registered by the chamber method. The net annual accumulation of carbon in the live part of mosses was estimated at 24–190 gC m−2 depending on the Sphagnum moss species. Long-term carbon accumulation rates obtained by radiocarbon analysis ranged from 28.5 to 57.2 gC m−2 yr−1, with local extremes of up to 176.2 gC m−2 yr−1. The obtained estimates of various carbon fluxes using EC and chamber methods, the accounting for Sphagnum growth and decomposition, and long-term peat accumulation provided information about the functioning of the peatland ecosystems at different spatial and temporal scales. Multiscale carbon flux monitoring reveals useful new information for forecasting the response of northern peatland carbon cycles to climatic changes.


Author(s):  
А.В. Данчева

Приведены данные исследований естественного лесовозобновления гари в условиях Западно-Сибирского среднетаежного равнинного лесного района таежной лесорастительной зоны (на примере Урайского лесничества, расположенного в юго-западной части Ханты-Мансийского автоном- ного округа – Югры на территории кондинского административного района). Оценка лесовозобновле- ния проведена по методу учетных лент, заложенных на расстоянии 50 и 100 м от стены леса. Данные исследований показали непрерывность лесовосстановительного процесса на гари. Отмечается наличие всходов, самосева и подроста высотных категорий «мелкий», «средний» и «крупный». лесовозобновле- ние гари происходит двумя древесными породами – сосной и березой. По существующим нормативам возобновление сосны оценивается как хорошее. По количеству всходов и подроста преобладает сосна. При удалении от стены леса на 100 м происходит уменьшение количества всходов и подроста всех кате- горий крупности в 2–3 раза в сравнении с аналогичными показателями на расстоянии 50 м от стены леса независимо от вида древесной породы. Во всех высотных категориях отмечается преобладание жизне- способного подроста сосны – до 90–100 %, что является основным показателем успешности лесовос- становления исследуемой гари на данном этапе развития. береза в большинстве случаев представлена сомнительными по жизнеспособности экземплярами. В качестве лесохозяйственных мероприятий мож- но предложить проведение мониторинга за состоянием подроста и уходные мероприятия за подростом. The results of features formations of post-fire pine undergrowth on burnt area of the middle taiga zone of Western Siberia (for example, Uraisk forestry department) in location of the Khanty-Mansi Autonomous Area. Undergrowth was studied on tapes laid out parallel to the forest edges at a distance of 50 and 100. According to studies it is observed of reafforestation continuity of burned areas. The presence of sprouting and undergrowth of the high- elevation categories «small», «medium» and «large» is noted. The burned areas reforestation with two tree species – pine and birch proceed. According to current specification, the pine natural regeneration is assessed as «normal». The amount of pine undergrowth is greater than the amount of birch undergrowth. To be at 100 m from forest edges the number of seedlings and undergrowth decreases by 2–3 times in comparison with the same indicators at 50 m from the forest edges. There is a predominance of vital pine undergrowth – up to 90–100 %. This is evidence of the successful reforestation of burned areas at this stage of development.


The Holocene ◽  
2021 ◽  
pp. 095968362110032
Author(s):  
Halinka Di Lorenzo ◽  
Pietro Aucelli ◽  
Giuseppe Corrado ◽  
Mario De Iorio ◽  
Marcello Schiattarella ◽  
...  

The Garigliano alluvial-coastal plain, at the Latium-Campania border (Italy), witnessed a long-lasting history of human-environment interactions, as demonstrated by the rich archaeological knowledge. With the aim of reconstructing the evolution of the landscape and its interaction with human activity during the last millennia, new pollen results from the coastal sector of the Garigliano Plain were compared with the available pollen data from other nearby sites. The use of pollen data from both the coastal and marine environment allowed integrating the local vegetation dynamics within a wider regional context spanning the last 8000 years. The new pollen data presented in this study derive from the analysis of a core, drilled in the coastal sector, which intercepted the lagoon-marshy environments that occurred in the plain as a response to the Holocene transgression and subsequent coastal progradation. Three radiocarbon ages indicate that the chronology of the analyzed core interval ranges from c. 7200 to c. 2000 cal yr BP. The whole data indicate that a dense forest cover characterized the landscape all along the Prehistoric period, when a few signs of human activity are recorded in the spectra, such as cereal crops, pasture activity and fires. The main environmental changes, forced by natural processes (coastal progradation) but probably enhanced by reclamation works, started from the Graeco-Roman period and led to the reduction of swampy areas that favoured the colonisation of the outer plain.


The Holocene ◽  
2018 ◽  
Vol 29 (1) ◽  
pp. 26-44 ◽  
Author(s):  
Manel Leira ◽  
Maria C Freitas ◽  
Tania Ferreira ◽  
Anabela Cruces ◽  
Simon Connor ◽  
...  

We examine the Holocene environmental changes in a wet dune slack of the Portuguese coast, Poço do Barbarroxa de Baixo. Lithology, organic matter, biological proxies and high-resolution chronology provide estimations of sediment accumulation rates and changes in environmental conditions in relation to sea-level change and climate variability during the Holocene. Results show that the wet dune slack was formed 7.5 cal. ka BP, contemporaneous with the last stages of the rapid sea-level rise. This depositional environment formed under frequent freshwater flooding and water ponding that allowed the development and post-mortem accumulation of abundant plant remains. The wetland evolved into mostly palustrine conditions over the next 2000 years, until a phase of stabilization in relative sea-level rise, when sedimentation rates slowed down to 0.04 mm yr−1, between 5.3 and 2.5 cal. ka BP. Later, about 0.8 cal. ka BP, high-energy events, likely due to enhanced storminess and more frequent onshore winds, caused the collapse of the foredune above the wetlands’ seaward margin. The delicate balance between hydrology (controlled by sea-level rise and climate change), sediment supply and storminess modulates the habitat’s resilience and ecological stability. This underpins the relevance of integrating past records in coastal wet dune slacks management in a scenario of constant adaptation processes.


2021 ◽  
Vol 9 ◽  
Author(s):  
Shengli Yang ◽  
Xiaojing Liu ◽  
Ting Cheng ◽  
Yuanlong Luo ◽  
Qiong Li ◽  
...  

Aeolian sediments hold key information on aeolian history and past environmental changes. Aeolian desertification and extensive land degradation have seriously affected the eco-environment in the Gannan region on the eastern Tibetan Plateau. Understanding the history of aeolian activities can deepen our understanding of the impacts of climatic changes on aeolian activities in the future. This study uses a detailed chronology and multiple proxy analyses of a typical aeolian section in Maqu to reconstruct aeolian activities in the region during the Holocene. Our results showed that aeolian activities have occurred in the eastern Tibetan Plateau since the early Holocene. Magnetic susceptibility, grain size records, and paleosols formation indicated a trend of stepwise weakening in aeolian activities from the early Holocene to the present. The weakening of aeolian activities was divided into three stages: ∼10.0–8.0 ka BP, ∼8.0–4.0 ka BP, and ∼4.0 ka BP to the present. Paleosols were primarily formed after ∼8.0 ka BP, and episodically interrupted aeolian activities processes in the Gannan region. Aeolian activity may increase in the Gannan region as the climate gradually warms. Climatic changes and local hydrological conditions have jointly affected the history of aeolian activities in this region.


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