Olga Borisova

Prof. Olga Borisova

Institute of Geography Russian Academy of Sciences

Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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10 November 2023 in Science Advances
Verified
Journal Article
Closed access
EPElena A. Pearce
Elena A. Pearce
Mazier FlorenceMazier Florence
Mazier Florence
SNSigne Normand
Signe Normand
RFRalph McKinlay Fyfe
Ralph McKinlay Fyfe
VAValérie Andrieu
Valérie Andrieu
Jens-Christian SvenningJens-Christian Svenning
Jens-Christian Svenning
The extent of vegetation openness in past European landscapes is widely debated. In particular, the temperate forest biome has traditionally been defined as dense, closed-canopy forest; however, some argue that large herbivores maintained greater openness or even wood-pasture conditions. Here, we address this question for the Last Interglacial period (129,000–116,000 years ago), before Homo sapiens –linked megafauna declines and anthropogenic landscape transformation. We applied the vegetation reconstruction method REVEALS to 96 Last Interglacial pollen records. We found that light woodland and open vegetation represented, on average, more than 50% cover during this period. The degree of openness was highly variable and only partially linked to climatic factors, indicating the importance of natural disturbance regimes. Our results show that the temperate forest biome was historically heterogeneous rather than uniformly dense, which is consistent with the dependency of much of contemporary European biodiversity on open vegetation and light woodland.

29 April 2023 in Land
Verified
Journal Article
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MSMaria Antonia Serge
Maria Antonia Serge
Mazier FlorenceMazier Florence
Mazier Florence
RFRalph McKinlay Fyfe
Ralph McKinlay Fyfe
Marie-Jose GaillardMarie-Jose Gaillard
Marie-Jose Gaillard
TKT. Klein
T. Klein
VZV. P. Zernitskaya
V. P. Zernitskaya
Reliable quantitative vegetation reconstructions for Europe during the Holocene are crucial to improving our understanding of landscape dynamics, making it possible to assess the past effects of environmental variables and land-use change on ecosystems and biodiversity, and mitigating their effects in the future. We present here the most spatially extensive and temporally continuous pollen-based reconstructions of plant cover in Europe (at a spatial resolution of 1° × 1°) over the Holocene (last 11.7 ka BP) using the ‘Regional Estimates of VEgetation Abundance from Large Sites’ (REVEALS) model. This study has three main aims. First, to present the most accurate and reliable generation of REVEALS reconstructions across Europe so far. This has been achieved by including a larger number of pollen records compared to former analyses, in particular from the Mediterranean area. Second, to discuss methodological issues in the quantification of past land cover by using alternative datasets of relative pollen productivities (RPPs), one of the key input parameters of REVEALS, to test model sensitivity. Finally, to validate our reconstructions with the global forest change dataset. The results suggest that the RPPs.st1 (31 taxa) dataset is best suited to producing regional vegetation cover estimates for Europe. These reconstructions offer a long-term perspective providing unique possibilities to explore spatial-temporal changes in past land cover and biodiversity.

4 April 2015
Verified
Book Chapter
Open access
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IBIrena Borzenkova
Irena Borzenkova
EZEduardo Zorita
Eduardo Zorita
Olga BorisovaOlga Borisova
Olga Borisova
LKLaimdota Kalniņa
Laimdota Kalniņa
DKDalia Kisielienė
Dalia Kisielienė
DSDimitry Subetto
Dimitry Subetto
This chapter summarises the climatic and environmental information that can be inferred from proxy archives over the past 12,000 years. The proxy archives from continental and lake sediments include pollen, insect remnants and isotopic data. Over the Holocene, the Baltic Sea area underwent major changes due to two interrelated factors—melting of the Fennoscandian ice sheet (causing interplay between global sea-level rise due to the meltwater and regional isostatic rebound of the earth’s crust causing a drop in relative sea level ) and changes in the orbital configuration of the Earth (triggering the glacial to interglacial transition and affecting incoming solar radiation and so controlling the regional energy balance). The Holocene climate history showed three stages of natural climate oscillations in the Baltic Sea region: short-term cold episodes related to deglaciation during a stable positive temperature trend (11,000–8000 cal year BP); a warm and stable climate with air temperature 1.0–3.5 °C above modern levels (8000–4500 cal year BP), a decreasing temperature trend; and increased climatic instability (last 5000–4500 years). The climatic variation during the Lateglacial and Holocene is reflected in the changing lake levels and vegetation , and in the formation of a complex hydrographical network that set the stage for the Medieval Warm Period and the Little Ice Age of the past millennium.

1 August 2017 in Doklady Earth Sciences
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Journal Article
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AVA. A. Velichko
A. A. Velichko
Olga BorisovaOlga Borisova
Olga Borisova
YKYu. M. Kononov
Yu. M. Kononov
EKEvgeny Konstantinov
Evgeny Konstantinov
RKR. N. Kurbanov
R. N. Kurbanov
PFP. D. Frolov
P. D. Frolov
An integrated study of the loess–soil sequence in the coastal exposure near the settlement of Beglitsa (Rostov oblast) allowed us, for the first time, to reconstruct the landscape-climatic changes that occurred in the eastern Azov region over the course of the Late Pleistocene. In the south of the periglacial zone, considerable differences between intensity of the loess accumulation in the Early and Late Valdai Cryochrons were revealed. In the Early Valdai Epoch, which corresponds roughly to the end of Marine Isotope Stage (MIS) 5 and MIS 4, loess accumulation occurred after completion of development of the Mezin pedocomplex and before the beginning of the Bryansk stage of soil development, i.e., over more than 20 000 years. In the much shorter Late Valdai Cryochron MIS 2 (10 000–12 000 years), loess accumulation reached 5 m. The data evaluation shows that the loess accumulation rates in the Early Valdai Epoch (~0.07 mm/year) and the Late Valdai Epoch (~0.5 mm/year) differ from each other by an order of magnitude.

19 November 2021 in Water Resources
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Journal Article
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Olga BorisovaOlga Borisova
Olga Borisova
Analysis of the modern geographic distribution of species of a specific fossil flora makes it possible to identify its closest modern region-analogue. Using the paleofloristic method, the modern region-analogues were determined for 22 radiocarbon-dated fossil floras. According to modern conditions within the centres of present concentration of the fossil floras, the changes in the main climatic indexes in the central East European Plain have been reconstructed for the interval from 24 to 8 thousand calibrated years BP. During the maximum phase of the Last Glaciation, the average annual air temperature was –6°C, the summer temperature was the lowest for the entire period of reconstruction, and continuous permafrost existed in the region. The first significant warming with an increase in the annual air temperature to 0°C took place 17–18 kyr BP. The sharpest short-term climate fluctuations were reconstructed for the Late Glacial when the differences in the annual air temperature between successive cold and warm phases were 7–10°C. In the studied interval, two stages of a significant increase in atmospheric precipitation are distinguished: 17–19 kyr BP (the Late Pleniglacial) and 13–14.5 kyr BP (the Bølling and Allerød interstadials). At the first stage, the predominance of a continental climate with annual temperature amplitude of ~30°C with continuous permafrost and rapid snow melting could lead to a significant increase in water discharge and runoff during spring floods, with relatively warm and dry summers. At the second stage, an increase in annual temperature to +1–2°С was accompanied by the degradation of permafrost and the rapid spread of forest vegetation with its stabilizing effect on the intra-annual runoff distribution. In this regard, the increase in precipitation in the Bølling and Allerød had little effect on the fluvial paleorelief compare to the stage of high water discharge in rivers at the end of the Late Pleniglacial.

13 November 2020 in Quaternary
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Journal Article
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APAndrei Panin
Andrei Panin
Olga BorisovaOlga Borisova
Olga Borisova
EKEvgeny Konstantinov
Evgeny Konstantinov
YBYury Belyaev
Yury Belyaev
EEEkaterina Andreevna Eremenko
Ekaterina Andreevna Eremenko
Aleksey SidorchukAleksey Sidorchuk
Aleksey Sidorchuk
Networks of dry valleys (or balkas) and hollows in the upper reaches of fluvial basins in extraglacial areas in the Penultimate Glaciation (Marine Isotope Stage 6—MIS 6) regions of the East European Plain demonstrate clear incision/aggradation rhythms corresponding to global glacial/interglacial climate cycles. The first phase of each incision/aggradation rhythm began after the global glacial maximum and was characterized by a cool and humid climate, permafrost and sparse vegetation, when high surface runoff and active linear erosion formed a dense network of gullies. The second phase occurred at the glacial–interglacial transition and the subsequent interglacial period with its warm and humid climate and dense vegetation. This phase was distinguished by the partial filling of fluvial forms with slopewash deposits, the transformation of gullies into dry valleys (balkas) and the subsequent stabilization of fluvial forms marked by the formation of mature soils on the sides and bottoms of balkas. The third phase of the rapid accumulation of balkas developed during the cold and dry part of the next glacial epoch, resulting in the balkas becoming shallow hollows filled in with sediments. The last full incision/aggradation rhythm occurred in the late MIS 6 to mid-MIS 2. The erosion network formed during the late MIS 6 was almost completely filled by mid-MIS 2, and its manifestation in the modern topography is limited to a network of shallow hollows in the upper parts of the fluvial systems. The modern (incomplete) incision/aggradation rhythm began in the late MIS 2 and caused the formation of the modern erosion landscape in the upper reaches of fluvial systems. This rhythm is now in the stabilization phase, and the main accumulation phase of this rhythm is still far in the future.