Jan Kavan
@uwr.edu.pl/en
Alfred Jahn Cold Regions Research Centre
University of Wroclaw
EDUCATION
2020: PhD in Physical Geography, Masaryk University in Brno, Czechia
RESEARCH INTERESTS
polar regions; glacier dynamics; paraglacial processes
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Christopher D. Stringer, John F. Boyle, Filip Hrbáček, Kamil Láska, Ondřej Nedělčev, Jan Kavan, Michaela Kňažková, Jonathan L. Carrivick, Duncan J. Quincey, and Daniel Nývlt
Elsevier BV
Jan Kavan, Radim Stuchlík, Jonathan L. Carrivick, Martin Hanáček, Christopher D. Stringer, Matěj Roman, Jakub Holuša, Pavla Dagsson‐Waldhauserová, Kamil Láska, and Daniel Nývlt
Wiley
AbstractThe termini of Icelandic glaciers are highly dynamic environments. Pronounced changes in frontal ablation in recent years have consequently changed ice dynamics. In this study, we reveal the inter‐seasonal dynamics of the Kvíárjökull ablation zone and proglacial zone using ArcticDEM and Sentinel‐2 images acquired between 2011 and 2021 and intra‐seasonal dynamics with repeated UAV surveys during summer 2021. Average glacier surface velocity in the ablation zone ranged from 51 m year−1 in 2015 up to 199 m year−1 in 2018, with maxima within the axial zone of the glacier and minima on the glacier edges. Coincidentally, and in accordance with glacier retreat/advance, the ice‐marginal proglacial lake fluctuated in its area, and we interpret that it was also a key factor in the development of the glacier terminus morphology. A complex spatial pattern of glacier surface elevation changes, including thickening in the frontal true left margin of the terminus, is interpreted to be due to variable subglacial topography, relatively fast ice flow from the accumulation zone and an insulating effect of glacier surface debris cover. In contrast, the true right (southern) part of the glacier terminus experienced thinning and retreat/disintegration also during the 2021 summer season, which we attribute to enhanced frontal ablation connected to the intrusion of lake water into the crevassed glacier terminus. Overall, this study suggests that where glaciers are developing ice‐marginal lakes complex patterns of glacier dynamics and mass loss can be expected, which will confound understanding of the short‐term evolution of these environments.
Zbyněk Engel, Kamil Láska, Jana Smolíková, and Jan Kavan
Cambridge University Press (CUP)
Abstract Glaciers cover 132 900 km2 around the Antarctic Ice Sheet, but few are subject to annual mass-balance measurements. Lookalike Glacier and Davies Dome on James Ross Island have been monitored since 2009, providing the third longest mass-balance record for the northern Antarctic Peninsula. These glaciers had a balanced mass budget over the period 2009/10–2014/15 but started to lose their mass thereafter. Between 2014/15 and 2020/21, mass change rates were −0.15 ± 0.13 and −0.26 ± 0.11 m w.e. a−1 for Lookalike Glacier and Davies Dome, respectively. The mean equilibrium-line altitudes over this period at Lookalike Glacier (362 ± 18 m a.s.l.) and Davies Dome (>427 ± 22 m a.s.l.) are 51 and >34 m higher compared to the previous 6-year period. The mean accumulation area ratio values determined for the period 2014/15–2020/21 are lower than the balanced-budget ratio indicating that glaciers are out of balance with the current climate. The data confirm the transition from positive to negative mass-balance periods around 2014/15, which is attributed to the change in air temperature trends. The mean summer temperature increased by 0.9°C between the periods 2009/10–2014/15 and 2015/16–2020/21 and melt-season temperatures became predominantly positive.
Jan Kollár, Kateřina Kopalová, Jan Kavan, Kristýna Vrbická, Daniel Nývlt, Linda Nedbalová, Marek Stibal, and Tyler J Kohler
Oxford University Press (OUP)
Abstract Glacier recession is creating new water bodies in proglacial forelands worldwide, including Antarctica. Yet, it is unknown how microbial communities of recently formed “young” waterbodies (originating decades to a few centuries ago) compare with established “old” counterparts (millennia ago). Here, we compared benthic microbial communities of different lake types on James Ross Island, Antarctic Peninsula, using 16S rDNA metabarcoding and light microscopy to explore bacterial and diatom communities, respectively. We found that the older lakes host significantly more diverse bacterial and diatom communities compared to the young ones. To identify potential mechanisms for these differences, linear models and dbRDA analyses suggested combinations of water temperature, pH, and conductivity to be the most important factors for diversity and community structuring, while differences in geomorphological and hydrological stability, though more difficult to quantify, are likely also influential. These results, along with an indicator species analysis, suggest that physical and chemical constraints associated with individual lakes histories are likely more influential to the assembly of the benthic microbial communities than lake age alone. Collectively, these results improve our understanding of microbial community drivers in Antarctic freshwaters, and help predict how the microbial landscape may shift with future habitat creation within a changing environment.
Jan Kavan and Mateusz C. Strzelecki
Wiley
Zbyněk Engel, Kamil Láska, Jan Kavan, and Jana Smolíková
Cambridge University Press (CUP)
AbstractThe retreat rates of Triangular Glacier since 1979 and its mass changes during the period 2014/15–2019/20 indicate the sensitive response of small ice masses on the eastern side of the Antarctic Peninsula to air temperature evolution. This cirque glacier in the northern part of James Ross Island receded rapidly during the period of regional warming in the late 20th century, losing 30.8% of its surface area between 1979 and 2006 (−1.7% a−1). The retreat rate then dropped to −0.3% a−1 following the regional cooling trend, but started to accelerate again (−0.8 to −2.3% a−1) with increasing air temperature since the summer 2014/15. Since the glaciological year 2015/16, Triangular Glacier has experienced enhanced snow melt, wind scour and permanent mass loss with annual mass balance ranging from −0.08 ± 0.35 to −0.56 ± 0.25 m w.e. The largest mass loss was observed in the glaciological year 2019/20, which included the warmest summer of the observation period. The cumulative mass balance of −1.66 ± 0.83 m w.e. over the years 2014/15–2019/20 is consistent with the termination of the positive mass-balance period that occurred in the north-eastern Antarctic Peninsula from 2009/10 to 2014/15.
Jan Kavan, Petra Luláková, Jakub Małecki, and Mateusz Czesław Strzelecki
Cambridge University Press (CUP)
Abstract Svalbard has experienced a dramatic increase in air temperature and glacier retreat since the end of the Little Ice Age. In many cases, this retreat has resulted in glaciers transitioning from being marine-terminating to land-terminating. Nordenskiöldbreen is an excellent contemporary example of this transition. A set of historical observations of glacier front positions was used to assess Nordenskiöldbreen's retreat rate and we found that the southern portion of the glacier front retreated by ~3500 m, since records began in 1896. The general retreat rate corresponds well with the air temperature trend during most of the 20th century. However, the average retreat rate has slowed since the 1990s despite increasing air temperatures. We show that this discrepancy between air temperature and retreat rate marks the transition from marine-terminating towards a land-terminating glacier, as the glacier's bedrock topography started to play an essential role in the glacier margin geometry, ice flow and retreat dynamics.
Jan Kavan, Filip Hrbáček, and Christopher D. Stringer
Informa UK Limited
Outi Meinander, Pavla Dagsson-Waldhauserova, Pavel Amosov, Elena Aseyeva, Cliff Atkins, Alexander Baklanov, Clarissa Baldo, Sarah L. Barr, Barbara Barzycka, Liane G. Benning,et al.
Copernicus GmbH
Abstract. Dust particles from high latitudes have a potentially large local, regional, and global significance to climate and the environment as short-lived climate forcers, air pollutants, and nutrient sources. Identifying the locations of local dust sources and their emission, transport, and deposition processes is important for understanding the multiple impacts of high-latitude dust (HLD) on the Earth's systems. Here, we identify, describe, and quantify the source intensity (SI) values, which show the potential of soil surfaces for dust emission scaled to values 0 to 1 concerning globally best productive sources, using the Global Sand and Dust Storms Source Base Map (G-SDS-SBM). This includes 64 HLD sources in our collection for the northern (Alaska, Canada, Denmark, Greenland, Iceland, Svalbard, Sweden, and Russia) and southern (Antarctica and Patagonia) high latitudes. Activity from most of these HLD sources shows seasonal character. It is estimated that high-latitude land areas with higher (SI ≥0.5), very high (SI ≥0.7), and the highest potential (SI ≥0.9) for dust emission cover >1 670 000 km2, >560 000 km2, and >240 000 km2, respectively. In the Arctic HLD region (≥60∘ N), land area with SI ≥0.5 is 5.5 % (1 035 059 km2), area with SI ≥0.7 is 2.3 % (440 804 km2), and area with SI ≥0.9 is 1.1 % (208 701 km2). Minimum SI values in the northern HLD region are about 3 orders of magnitude smaller, indicating that the dust sources of this region greatly depend on weather conditions. Our spatial dust source distribution analysis modeling results showed evidence supporting a northern HLD belt, defined as the area north of 50∘ N, with a “transitional HLD-source area” extending at latitudes 50–58∘ N in Eurasia and 50–55∘ N in Canada and a “cold HLD-source area” including areas north of 60∘ N in Eurasia and north of 58∘ N in Canada, with currently “no dust source” area between the HLD and low-latitude dust (LLD) dust belt, except for British Columbia. Using the global atmospheric transport model SILAM, we estimated that 1.0 % of the global dust emission originated from the high-latitude regions. About 57 % of the dust deposition in snow- and ice-covered Arctic regions was from HLD sources. In the southern HLD region, soil surface conditions are favorable for dust emission during the whole year. Climate change can cause a decrease in the duration of snow cover, retreat of glaciers, and an increase in drought, heatwave intensity, and frequency, leading to the increasing frequency of topsoil conditions favorable for dust emission, which increases the probability of dust storms. Our study provides a step forward to improve the representation of HLD in models and to monitor, quantify, and assess the environmental and climate significance of HLD.
Jan Kavan, Iwo Wieczorek, Guy D. Tallentire, Mihail Demidionov, Jakub Uher, and Mateusz C. Strzelecki
MDPI AG
Glacier-fed hydrological systems in high latitude regions experience high seasonal variation in meltwater runoff. The peak in runoff usually coincides with the highest air temperatures which drive meltwater production. This process is often accompanied by the release of sediments from within the glacier system that are transported and suspended in high concentrations as they reach the proglacial realm. Sediment-laden meltwater is later transported to the marine environment and is expressed on the surface of fjords and coastal waters as sediment plumes. Direct monitoring of these processes requires complex and time-intensive fieldwork, meaning studies of these processes are rare. This paper demonstrates the seasonal dynamics of the Trebrevatnet lake complex and evolution of suspended sediment in the lake and sediment plumes in the adjacent Ekmanfjorden. We use the Normalized Difference Suspended Sediment Index (NDSSI) derived from multi-temporal Sentinel-2 images for the period between 2016–2021. We propose a new SSL index combining the areal extent of the sediment plume with the NDSSI for quantification of the sediment influx to the marine environment. The largest observed sediment plume was recorded on 30 July 2018 and extended to more than 40 km2 and a SSL index of 10.4. We identified the greatest sediment concentrations in the lake in the beginning of August, whereas the highest activity of the sediment plumes is concentrated at the end of July. The temporal pattern of these processes stays relatively stable throughout all ablation seasons studied. Sediment plumes observed with the use of optical satellite remote sensing data may be used as a proxy for meltwater runoff from the glacier-fed Trebrevatnet system. We have shown that remote-sensing-derived suspended sediment indexes can (after proper in situ calibration) serve for large scale quantification of sediment flux to fjord and coastal environments.
Jan Kavan and Barbora Halašková
Cambridge University Press (CUP)
Abstract Climate change has become significantly pronounced in the Arctic over recent decades. In addition to these climate effects, the environment has experienced severe anthropogenic pressure connected to increased human activities, including the exploitation of natural resources and tourism. The opportunity to exploit some of the natural riches of Svalbard was promptly grasped by the Soviet Union well before the 1940s. In this paper, we present the story of Pyramiden, a mining settlement in central Svalbard. The Soviet town experienced its golden age in the 1970–1980s but fell into decline in the late 1990s which corresponds well with the overall economic and geopolitical situation of the Soviet Union. The impacts of past mining activities and related urban infrastructure development are illustrated with the use of historic aerial photographs. The most pronounced changes in the terrain configuration were connected to adjustments of the river network, construction of roads, water reservoirs, and obviously mining-related activities. The natural processes overwhelmed the city infrastructure rather quickly after the abandonment of the town in 1998, though some traces of human activities may persist for decades or centuries. Nowadays, Russia has been attempting to recover the settlement especially through support of tourism and research activities.
Jan Kavan, Guy D. Tallentire, Mihail Demidionov, Justyna Dudek, and Mateusz C. Strzelecki
MDPI AG
Tidewater glaciers on the east coast of Svalbard were examined for surface elevation changes and retreat rate. An archival digital elevation model (DEM) from 1970 (generated from aerial images by the Norwegian Polar Institute) in combination with recent ArcticDEM were used to compare the surface elevation changes of eleven glaciers. This approach was complemented by a retreat rate estimation based on the analysis of Landsat and Sentinel-2 images. In total, four of the 11 tidewater glaciers became land-based due to the retreat of their termini. The remaining tidewater glaciers retreated at an average annual retreat rate of 48 m year−1, and with range between 10–150 m year−1. All the glaciers studied experienced thinning in their frontal zones with maximum surface elevation loss exceeding 100 m in the ablation areas of three glaciers. In contrast to the massive retreat and thinning of the frontal zones, a minor increase in ice thickness was recorded in some accumulation areas of the glaciers, exceeding 10 m on three glaciers. The change in glacier geometry suggests an important shift in glacier dynamics over the last 50 years, which very likely reflects the overall trend of increasing air temperatures. Such changes in glacier geometry are common at surging glaciers in their quiescent phase. Surging was detected on two glaciers studied, and was documented by the glacier front readvance and massive surface thinning in high elevated areas.
Jan Kavan
Informa UK Limited
ABSTRACT
With the ongoing climate change and the prolongation of the summer melting season and increasing air temperature that this entails, fluvial transport is likely to become a more important process shaping the deglaciated areas of Antarctica. Quantification of suspended sediment transport in the deglaciated catchment of the Bohemian Stream is presented in this study. It was shown that a large amount of fine-grained material is being transported even in the relatively small catchment during the short period of the Antarctic summer. The average calculated suspended sediment concentration during the 2018 austral summer reached 274.6 mg l−1, which corresponded to an average suspended sediment load of 3662 kg day−1 and suspended sediment yield of 68 t km−2 year−1 when considering the flow season to be approximately 4 months per year. Such values are considerably higher than those reported from continental Antarctica; however, they are lower compared to most of the Arctic catchments.
Jan Kavan and Vincent Haagmans
Cambridge University Press (CUP)
AbstractThe dynamics of seasonal snow ablation on six glaciers in central Spitsbergen (Dicksonland) were assessed by examining a set of Sentinel-2 satellite images covering the summer ablation season for the period 2016–19. All glaciers lost 80% or more of their surface snow cover during the studied ablation seasons. This bolsters the recently observed trend of local glacier thinning, even at higher altitudes. Snow ablation dynamics are highly dependent on the glaciers altitudes, their position relative to the prevailing wind direction and the exposure to insolation. The accumulation areas of the studied glaciers were delimited based on the overlap of the minimum extent of snow-covered areas in the four consecutive studied summer seasons. The high temporal and spatial resolutions of available images enabled a detailed description of the seasonal snow ablation dynamics. Moreover, an estimate of the average number of days with below threshold glacier snow cover was made. This study contributes to our understanding of recent processes and might further support the modelling of glacier melt and subsequent runoff.
Jan Kavan, Linda Nedbalová, Daniel Nývlt, Tomáš Čejka, and Juan Manuel Lirio
Cambridge University Press (CUP)
AbstractClimate change affects various components of the polar environment, including lacustrine systems in many regions of the Antarctic Peninsula. However, the recent status of these life-preserving habitats remains poorly known. We performed field geomorphological mapping and limnological characterization of lakes distributed across Devil's Bay in the northern area of Vega Island, James Ross Archipelago, and described some significant changes in their physical and chemical properties during the 2013 summer season. Fifty lakes were described in the area, even though the area is relatively small (~12 km2). Six major lake types were distinguished based on their geomorphological settings and their origins, and their hydrochemical properties were compared with the neighbouring lake districts. The geomorphic characteristics of the lakes range from stable lakes on till plains (21 out of 50 lakes), to kettle lakes on fresh moraines with an unstable shoreline, to very dynamic ice-contact lakes with fluctuating water levels and inundated areas. The ice-contact lake dynamics were observed using ‘Lake Payer’ as an example. At the interface between hydrology and geosciences, this study provides new and original data from a yet largely unexplored region and emphasizes the importance of cross-disciplinary research in polar sciences.
Jan Kavan, Kamil Láska, Adam Nawrot, and Tomasz Wawrzyniak
MDPI AG
High Latitude Dust (HLD) deposition in the surface snow layer in two distant locations in Svalbard (Hornsund and Pyramiden) were collected during the June/July 2019 field campaign and examined in the laboratory. Despite the differences in their climate and topography, both locations are characterised by very similar spatial patterns of the deposition. On the one hand, strong linear negative relationship between the altitude of the sample taken and its concentration was found in low altitude (below 300 m a.s.l.), suggesting a strong influence of local HLD sources. On the other hand, almost constant concentrations were found at higher elevated sampling sites (above 300 m a.s.l.). This suggests a predominantly long-range transport in high altitude areas. The importance of local sources in the lower altitude corresponds well with the generally higher concentrations of HLD in the Pyramiden area. This region has a drier, continental climate and more deglaciated bare land surfaces, which favour more sediment to be uplifted in comparison with the more maritime climate of Hornsund area in the southern part of Svalbard. The spatial division between the local and long-range transport is supported by the proportion of certain lithophile elements in the altitude gradient.
Jan Kavan, Daniel Nývlt, Kamil Láska, Zbyněk Engel, and Michaela Kňažková
Wiley
High‐latitude dust (HLD) depositions on four glaciers of James Ross Island (the Ulu Peninsula) were analysed. The deposition rate on the selected glaciers varies from 11.8 to 64.0 g m−2, which is one order of magnitude higher compared to the glaciers in Antarctica or elsewhere in the world. A strong negative relationship between the sediment amount and altitude of a sampling site was found. This is most likely caused by the higher availability of aeolian material in the atmospheric boundary layer. General southerly and south‐westerly wind directions over the Ulu Peninsula – with exceptions based on local terrain configuration – help to explain the significantly lower level of sediment deposition on San Jose Glacier and the high level on Triangular Glacier. X‐ray fluorescence (XRF) spectrophotometry was used to estimate the relative proportions of the main and trace (lithophile) elements in the sediment samples. Both the sediment amount and the XRF results are analysed in a depth profile at each locality and compared among the glaciers, suggesting long‐range transport of fine mineral material from outside James Ross Island. The distribution of aeolian sediment among the glaciers corresponds well with the prevailing wind direction on the Ulu Peninsula. © 2020 John Wiley & Sons, Ltd.
Jan Kavan
Informa UK Limited
Abstract Changes in the position of the shore in the vicinity of Kapp Napier in central Svalbard was described. The overall advance of the shore was probably related to high input of the sediment material originating from erosion of the coastal areas south of the Kapp Napier locality and high input of material from adjacent glacifluvial system of Nordenskiöld glacier with its marginal water streams. Fast evolution of glacier retreat related processes after the Little Ice Age was a secondary driver of the dynamic changes in the central Svalbard coastal areas especially in the first half of the 20th century. The highly dynamic longshore currents in the area altogether with still ongoing glacio-isostatic uplift played an important role in the process as well. The most active parts of the shore experienced advance of almost 100 m since 1908 to 2009. On the other hand, a small part of the coast retreated of about 20 m. Most of the study area experienced aggradation (65%), 30% of the coast was stable and about 5% of the coast has undergone minor retreat. The maximum aggradation rate of 0.96 m/year corresponds well with similar sites in the vicinity. Graphical Abstract
Marie Bulínová, Tyler J. Kohler, Jan Kavan, Bart Van de Vijver, Daniel Nývlt, Linda Nedbalová, Silvia H. Coria, Juan M. Lirio, and Kateřina Kopalová
MDPI AG
Diatoms are useful ecological and paleolimnological indicators routinely used to reconstruct past conditions and monitor environmental change. Despite this, diatom assemblages from lake sediment cores are often difficult to interpret due to a limited knowledge of the ecology of some species, some of which may originate from the adjacent limno-terrestrial landscape. Here, we compare diatom assemblages from two recently published Antarctic lake sediment cores collected from the northeast and southwest sides of Vega Island, Antarctic Peninsula. We further compare the sediment core assemblages with adjacent modern communities inhabiting four different limno-terrestrial habitat types to gauge the importance of landscape connectivity in determining paleo-assemblage structure. We found that diatom assemblage composition was significantly different between the two cores, and our survey of modern habitats further revealed habitat type to be an important factor determining the composition of limno-terrestrial samples. Differences in modern habitats were driven primarily by Chamaepinnularia krookiformis in mosses, Nitzschia paleacea in ponds, and Fistulifera pelliculosa in streams. When modern communities were compared with paleo-assemblages through ordination, the cored lake from the northeast side, which exhibited greater hydrological connectivity with its surroundings, clustered more closely with the adjacent modern samples. Meanwhile, the cored lake from the southwest side, which was more hydrologically isolated, formed a distinct cluster separate from the others. Overall, species richness and diversity were greater on the southwest side of the island than the northeast, and the known distributions of diatom taxa supported the notion that Vega Island was a transitional zone between the Maritime and Continental Antarctic bioregions. These results collectively suggested that while environmental and spatial controls may be influential in determining diatom community composition, the unique hydrogeological setting of individual waterbodies was an important consideration for determining the assemblage structure of lake cores. This paper furthermore expanded ongoing research of diatom diversity and distributions on maritime Antarctic islands, which will improve diatom-based interpretations for regional ecological monitoring and paleolimnology in the future.
Klára Ambrožová, Kamil Láska, and Jan Kavan
Wiley
The influence of synoptic‐scale circulation on air temperature variation in the ice‐free and glaciated areas on the eastern side of the Antarctic Peninsula (AP) has been analysed. For this purpose, a new classification of atmospheric circulation with 15 synoptic patterns in the AP region was developed using the self‐organizing maps technique. The synoptic patterns were compared with air temperature observations from coastal and glacial sites on James Ross Island, northeastern AP, in the period 2005–2015. The most frequent synoptic pattern with a frequency of 13.7% was dominated by a low‐pressure centre in the northwestern Bellingshausen Sea, which extended over the AP to the Weddell Sea. On the other hand, the largest inter‐annual variability was observed for a synoptic pattern with a low‐pressure centre in the southern Bellingshausen Sea. This synoptic pattern also had the highest air temperature anomalies at both investigated sites year‐round. Air temperature anomalies at the lower lying site (Mendel station) were the lowest during a high‐pressure ridge dominating the AP region due to a combination of local and synoptic‐scale processes. At Davies Dome, the glacial site, southerly barrier winds advecting cold air from the ice‐covered Weddell Sea during a strong low‐pressure system in the Weddell Sea ensured the coldest air temperature anomalies.
Jan Kavan
Informa UK Limited
ABSTRACT Glaciers in central Svalbard are retreating since their Little Ice Age maximum, dated in the area to around 1900. Past areal extent of glaciers can confidently be reconstructed based on end moraine position. However, reconstructions of thickness and volume of glaciers remain relatively more complicated and uncertain. In this study, past changes in thickness and volume of the Ferdinand Glacier was reconstructed based on Structure-from-Motion techniques and field dGPS measurements in combination with analysis of historic photos from 1908 and aerial photos from 1938. According to the comparison of the historic and recent photograph, the 1908 glacier front height was estimated to 50 m and the glacier volume to 91.5 mil m3 and the 1938 glacier volume estimated to 76.1 mil m3, in comparison to 6.29 mil m3 in 2014. This means more than 90% loss of volume since 1938. Melting of the glacier in the first half of the twentieth century resulted in thinning and lowering of the glacier surface together with substantial ice volume loss, whereas the areal extent was almost not affected. Considering the 2014 mean ice thickness, together with ongoing climate warming, it is likely that the Ferdinand Glacier will completely disappear within the next 30 years.
M. Kňažková, F. Hrbáček, J. Kavan, and D. Nývlt
Universidad de la Rioja
In this study we aim to describe the processes leading to the creation of a specific periglacial and aeolian landsystem, which evolves around the hyaloclastite breccia boulders on James Ross Island, north-eastern Antarctic Peninsula. These boulders were deposited as a result of the Late Holocene advance of Whisky Glacier, forming a well-developed boulder train approximately 5-km long, stretching from Whisky Glacier moraine to Brandy Bay. The combination of ground temperature monitoring, snow cover measurements, grain size analysis and field survey were used to quantify and understand the interplay of periglacial and aeolian processes leading to the formation of the specific meso-scale landsystem around the boulders. The ground temperature probes were installed during January 2017 in the vicinity of two selected boulders. The two study sites, at Monolith Lake (large boulder) and Keller Stream (smaller boulder), were also fitted with snow stakes and trail cameras. An automatic weather station (AWS) on the Abernethy Flats, located approximately two kilometres to the north-west, was used as a reference site for ground temperature and snow cover thickness. The hyaloclastite breccia boulders act as obstacles to wind and trap wind-blown snow, resulting in the formation of snow accumulations on their windward and lee sides. These accumulations affect ground thermal regime and lead to the transport of fine particles by meltwater from the snow during the summer season. The snow cover also traps wind-blown fine sand resulting in the formation of fine-grained rims on the windward and lee sides of the boulders after the snow has melted. Furthermore, the meltwater affects ground moisture content, creating favourable, but spatially limited conditions for colonisation by mosses and lichens.
Jan Kavan and Veronika Anděrová
Masaryk University Press
The increasing number of visitors in polar regions and demand for outdoor extreme activities create a pressure on local fragile ecosystems. Two examples of mechanical disturbances of the glacier forefields are presented in this study to demonstrate the impacts of different frequencies of visits on the local environment. Foxfonna study site experience only minor disturbances in comparison with the Langjökull study site on Iceland. This is due to the number of tourists visiting the two localities and also the means of transportation used for reaching the ice caps. It is likely that with still ongoing increase of number of tourists coming to these localities, the anthropogenic pressure will continue to grow. The combination of human pressure and ongoing climate change can have irreversible effects on sensitive local environment especially in places easily accessible for tourists.
Tomáš Čejka, Daniel Nývlt, Kateřina Kopalová, Marie Bulínová, Jan Kavan, Juan M. Lirio, Silvia H. Coria, and Bart van de Vijver
Elsevier BV
Jan Kavan and Veronika Anděrová
Walter de Gruyter GmbH
Abstract A new non-invasive method based on picture analysis was used to estimate the conditions in Svalbard reindeer populations. The well-being of an individual subject is often expressed through visual indices. Two distinct reindeer populations were compared based on their antler parameters. Relative antler size and number of tines are variables supposed to reflect correspondingly the environmental conditions of sedentary populations within the growing season. The occurrence areas of two studied populations are distinctly isolated – separated with high mountain ridges, glaciers and fjords. The population in Petuniabukta occupies a sparsely vegetated region with harsh climatic conditions, whereas Skansbukta represents an area with continuous tundra vegetation cover, milder climatic conditions and, consequently, also a longer vegetation season. These environmental factors probably caused significant differences in the relative antler size and number of tines in the studied species. The Skansbukta population exhibited a larger relative antler size and higher number of tines than the population in Petuniabukta (both parameters differed significantly, p < 0.01). This difference reflects concisely the different environmental conditions of both locations. A comparison of Skansbukta population antler characteristics between years 2017 and 2018 did not reveal significant changes, most probably due to very similar atmospheric conditions in these two years (in terms of air temperature).