Tundra Communities Research Articles

The changing biodiversity of the Arctic flora in the Anthropocene.

The plants of the circumpolar Arctic occupy a dynamic system that has been shaped by glacial cycles and climate change on evolutionary timescales. Yet rapid climatic change can compromise the floristic diversity of the tundra, and the ecological and evolutionary changes in the Arctic from anthropogenic forces remain understudied. In this review, we synthesize knowledge of Arctic floral biodiversity across the entirety of the region within the context of its climatic history. We present critical gaps and challenges in modeling and documenting the consequences of anthropogenic changes for Arctic flora, informed by data from the Late Quaternary (~20 ka). We found that previous forecasts of Arctic plant responses to climate change indicate widespread reductions in habitable area with increasing shrub growth and abundance as a function of annual temperature increase. Such shifts in the distribution and composition of extant Arctic flora will likely increase with global climate through changes to the carbon cycle, necessitating a unified global effort in conserving these plants. More data and research on the continuity of tundra communities are needed to firmly assess the risk climate change poses to the Arctic.

Greening of Svalbard in the twentieth century driven by sea ice loss and glaciers retreat

The greening of previously barren landscapes in the Arctic is one of the most relevant responses of terrestrial ecosystem to climate change. Analyses of satellite data (available since ~1980) have revealed a widespread tundra advance consistent with recent global warming, but the length is insufficient to resolve the long-term variability and the precise timing of the greening onset. Here, we measured plant-derived biomarkers from an Arctic fjord sediment core as proxies for reconstructing past changes in tundra vegetation during the transition from the Little Ice Age to modern warming. Our findings revealed a rapid expansion of the tundra since the beginning of the twentieth century, largely coinciding with the decline of summer sea ice extent and glacier retreat. The greening trend inferred from biomarker analysis peaked significantly in the late 1990s, along with a shift in the tundra community towards a more mature successional stage. Most of these signals were consistent with the biomolecular fingerprints of vascular plant species that are more adapted to warmer conditions and have widely expanded in proglacial areas during recent decades. Our results suggest that the greening of Arctic fjords may have occurred earlier than previously thought, improving our mechanistic understanding of vegetation-climate-cryosphere interactions that will shape tundra vegetation under future warming projections.

Permafrost Degradation and Vegetation Growth Beyond the Polar Circle in Siberia

Permafrost thawing is potentially a crucial but poorly investigated factor that influences vegetation dynamics in the Arctic. We studied the permafrost thaw rate beyond the Polar Circle in Siberia. We analyzed its influence on the larch (Larix spp.) growth and Arctic vegetation (sparse larch forests, tundra, and forest–tundra communities) productivity (NPP). We checked the following hypotheses: (1) satellite gravimetry is valid for permafrost thawing analysis; (2) meltwater runoff stimulated trees’ growth and NPP. We used satellite (GRACE, Terra/MODIS) and field data, and larch tree radial growth index measurements. We found a continuous negative trend in the terrestrial water content (r2 = 0.67) caused by permafrost thawing beyond the Polar Circle. Runoff is maximal in West and Mid Siberia (9.7 ± 2.9 kg/m2/y) and decreases in the eastward direction with minimal values in the Chukotka Peninsula sector (−2.9 ± 3.2 kg/m2/y). We found that the growth increment of larch trees positively correlated with meltwater runoff (0.5…0.6), whereas the correlation with soil water content was negative (−0.55…−0.85). Permafrost thawing leads to an increase in the Arctic vegetation productivity. We found a positive trend in NPP throughout the Siberian Arctic (r2 = 0.30). NPP negatively correlated with soil water content (r = −0.55) and positively with meltwater runoff (West Siberia, r = 0.7). An increase in VPD (vapor pressure deficit) and air and soil temperatures stimulated the larch growth and vegetation NPP (r = 0.5…0.9 and r = 0.6…0.9, respectively). Generally, permafrost degradation leads to improved hydrothermal conditions for trees and vegetation growth and contributes to the preservation of the Arctic as a carbon sink despite the increase in burning rate.

Traditional polar transportation seen from within the culture

This paper explores cultural narratives and oral histories related to two examples of traditional northern transport—long seal hunting journeys in the Baltic region and nomadic reindeer travel in northeastern Siberia. Ample material has been collected and reviewed regarding means of nonmotorised transport in the polar regions. However, scientific literature concerning the experiences and perspectives of the Indigenous and traditional community members who took part in these journeys remains scarce. This article explores the recorded narratives of two people involved in the journeys described. It assesses how these long-distance travels form significance, meaning, observations, and belonging to landscapes for these people. This analysis reveals that, rather than inhabiting northern ice and tundra scapes that are often described as barren and devoid of life, seal hunters and reindeer herders live in story-scapes rich in meaning. The sacred places, surrender to ice flow dynamics, and ways of living “inside” northern habitats that emerge from these testimonies offer a skeleton key for re-reading the misunderstood homelands of Arctic and tundra communities.

Greening of Svalbard

Svalbard, located between 76°30′N and 80°50′N, is among the regions in the world with the most rapid temperature increase. We processed a cloud-free time-series of MODIS-NDVI for Svalbard. The dataset is interpolated to daily data during the 2000–2022 period with 232 m pixel resolution. The onset of growth, with a clear phenological definition, has been mapped each year. Then the integrated NDVI from the onset (O) of growth each year to the time of average (2000–2022) peak (P) of growth (OP NDVI) have been calculated. OP NDVI has previously shown high correlation with field-based tundra productivity. Daily mean temperature data from 11 meteorological stations are compared with the NDVI data. The OP NDVI values show very high and significant correlation with growing degree days computed from onset to time of peak of growth for all the meteorological stations used. On average for the entire Svalbard, the year 2016 first had the highest greening (OP NDVI values) recorded since the year 2000, then the greening in 2018 surpassed 2016, then 2020 surpassed 2018, and finally 2022 was the year with the overall highest greening by far for the whole 2000–2022 period. This shows a rapid recent greening of Svalbard very strongly linked to temperature increase, although there are regional differences: the eastern parts of Svalbard show the largest variability between years, most likely due to variability in the timing of sea-ice break-up in adjacent areas. Finally, we find that areas dominated by manured moss-tundra in the polar desert zone require new methodologies, as moss does not share the seasonal NDVI dynamics of tundra communities.

Influence of tundra fire severity on vegetation recovery in the Northwest Territories

Anthropogenic climate change has driven an increase in the frequency, size, and severity of fires at high latitudes. Recent research shows that increasing fire severity in the subarctic is altering the trajectories of forest succession, but to date, research on the effect of fire severity on tundra succession has been limited. In this study, we investigated short-term recovery of shrub tundra communities following fire in the Tuktoyaktuk Coastal Plain and Anderson River Plain ecoregions of the Northwest Territories. To understand the effects of fire severity, we documented vegetation and permafrost recovery within moderately burned, severely burned, and unburned portions of six tundra fires that burned in 2012. We found that vegetation structure at moderately and severely burnt sites recovered rapidly toward pre-fire levels, but that differences in community composition, characterized by a decrease in shrub and lichen cover as well as an increase in abundance of ruderals and graminoids, persisted at severely burned sites. The persistence of thermal changes and increased thaw depth indicate that while biotic recovery can occur promptly, severe fire may have long-term impacts on belowground conditions.

Summer drought weakens land surface cooling of tundra vegetation

Siberia experienced a prolonged heatwave in the spring of 2020, resulting in extreme summer drought and major wildfires in the North-Eastern Siberian lowland tundra. In the Arctic tundra, plants play a key role in regulating the summer land surface energy budget by contributing to land surface cooling through evapotranspiration. Yet we know little about how drought conditions impact land surface cooling by tundra plant communities, potentially contributing to high air temperatures through a positive plant-mediated feedback. Here we used high-resolution land surface temperature and vegetation maps based on drone imagery to determine the impact of an extreme summer drought on land surface cooling in the lowland tundra of North-Eastern Siberia. We found that land surface cooling differed strongly among plant communities between the drought year 2020 and the reference year 2021. Further, we observed a decrease in the normalized land surface cooling (measured as water deficit index) in the drought year 2020 across all plant communities. This indicates a shift towards an energy budget dominated by sensible heat fluxes, contributing to land surface warming. Overall, our findings suggest significant variation in land surface cooling among common Arctic plant communities in the North-Eastern Siberian lowland tundra and a pronounced effect of drought on all community types. Based on our results, we suggest discriminating between functional tundra plant communities when predicting the drought impacts on energy flux related processes such as land surface cooling, permafrost thaw and wildfires.

Bacterial and fungal communities in sub-Arctic tundra heaths are shaped by contrasting snow accumulation and nutrient availability.

Climate change is affecting winter snow conditions significantly in northern ecosystems but the effects of the changing conditions for soil microbial communities are not well-understood. We utilized naturally occurring differences in snow accumulation to understand how the wintertime subnivean conditions shape bacterial and fungal communities in dwarf shrub-dominated sub-Arctic Fennoscandian tundra sampled in mid-winter, early, and late growing season. Phospholipid fatty acid (PLFA) and quantitative PCR analyses indicated that fungal abundance was higher in windswept tundra heaths with low snow accumulation and lower nutrient availability. This was associated with clear differences in the microbial community structure throughout the season. Members of Clavaria spp. and Sebacinales were especially dominant in the windswept heaths. Bacterial biomass proxies were higher in the snow-accumulating tundra heaths in the late growing season but there were only minor differences in the biomass or community structure in winter. Bacterial communities were dominated by members of Alphaproteobacteria, Actinomycetota, and Acidobacteriota and were less affected by the snow conditions than the fungal communities. The results suggest that small-scale spatial patterns in snow accumulation leading to a mosaic of differing tundra heath vegetation shapes bacterial and fungal communities as well as soil carbon and nutrient availability.

The Enmynveem mammoth and vegetation changes in arctic Chukotka during the Late Quaternary

Abstract Mining operations in the Enmynveem valley, northeastern Siberia, exposed a well-preserved right hind leg of Mammuthus primigenius (woolly mammoth), dated to ca. 37,500 cal yr BP. The leg had a fracture that crosscut the midsections of the tibia and fibula. Additional skeletal and soft tissue remains, including two mummified adults (Berezovka, ca. 47,200 cal yr BP; Bolshoi Lyakhovsky, ca. 37,000 cal yr BP), document the presence of mammoths in interior mountain valleys and across both northern and southern coasts of far northeastern Siberia during Marine Isotope Stage (MIS) 3. A mosaic of herb-dominated tundra communities characterized the vegetation of the Enmynveem site during late to middle MIS 3 and MIS 2 (ca. 37,000–17,000 cal yr BP). Shrubs were limited to Salix during the late Pleistocene, whereas Betula also may have been present in sheltered sites during MIS 3. Herb communities remained dominant during the late Pleistocene–Early Holocene transition, although shrub Betula increased during this interval. By ca. 10,200 cal yr BP, the vegetation was Betula–Alnus shrub tundra. Larix and Pinus pumila were established in the valley by ca. 8700 cal yr BP and ca. 5700 cal yr BP, respectively.

On stable and quasi-chaotic regimes in a one-dimensional unimodal mapping obtained by modeling the dynamics of a biological population

The paper considers the properties of the difference equation describing the dynamics of the animal population, obtained earlier in the framework of studies of tundra communities. We have considered a special case in which the model is represented by a one-parameter difference equation that defines a one-dimensional unimodal mapping of a segment into itself, similar to the well-known triangular (tent) mapping, supplemented by a region with a constant value. A change in the mapping parameter generates a bifurcation scenario, in which stability zones arise, characterized by orbits of a constant period, interspersed with zones with more complicated, “quasi-chaotic” regimes. Based on the properties of the n-iterated triangular mapping, a necessary and sufficient condition for the localization of cyclic orbits in the considered type of unimodal mappings is formulated, which makes it possible to identify stability regions for any given period n. On the basis of this condition an algorithm for detecting stability zones is proposed. The main subject of the study is the fractal properties of the set, which is the complement of the obtained set of stability regions to the entire domain of mapping definition. The dynamics of the DH (n) value is obtained, the limit of which at n → ∞ is equal to the fractal dimension dH . It is shown that in the studied range of n (2 ≤ n ≤ 22), the DH (n) < 0.9, which suggest that dH < 1. If so, then according to the definition of a fractal set, its topological dimension is dT = 0, which means that the complement of the set of stability regions consists of isolated points.

Holocene vegetation dynamics of the Yamal Peninsula based on palaeobotanical data from relict peat bog deposits

We have performed a comprehensive paleoecological study of the peat bog deposits from six localities of the Seyakha, Yuribey and Khadytayakha rivers in the subarctic tundra zone on the Yamal Peninsula. Radiocarbon dating, as well as pollen and plant macrofossil analyses were used to track the chronological changes of the plant communities on the peninsula along the North-South transect in the Late Glacial and Postglacial periods. It was found that open woodland with tree birch and spruce existed in the Yuribey river valley during the Bölling-Allerød interstadial (between 14.7 and 12.7 cal. ka BP). Shrub tundra with Betula nana was widespread in this area during the Younger Dryas, between 12.6 and 11.7 cal. ka BP, under climatic conditions similar to modern ones. The spread of arboreal species (Betula sect. Betula, Picea obovata, Larix sibirica) and associated boreal herbaceous plants began later (between 10.2 and 9.7 cal. ka BP) as climatic conditions improved. The most favorable conditions for tree birch and larch existed in the Seyakha river valley between 10.2 and 8.7 cal. ka BP, whereas the best conditions for the same species and spruce in the Yuribey river valley were observed between 10.2 and 4.4 cal. ka BP. It was much warmer than it is today, and open woodland or even closed forests were widespread. Forest degradation and spread of open landscapes with tundra communities occurred in the Seyakha river valley after 8.7–8.5 cal. ka BP and in the Yuribey river valley after 4.7–4.3 cal. ka BP. Climatic conditions became similar to modern ones. Today, arboreal species grow in the Khadytayakha river valley, forming extrazonal forest communities in the subarctic tundra zones.

Cascading effects of earthworm invasion increase graminoid density and rodent grazing intensities.

Human-mediated dispersal of non-native earthworms can cause substantial changes to the functioning and composition of ecosystems previously earthworm-free. Some of these earthworm species have the potential to "geoengineer" soils and increase plant nitrogen (N) uptake. Yet the possible consequences of increased plant N concentrations on rodent grazing remains poorly understood. In this study, we present findings from a common garden experiment with two tundra communities, meadow (forb dominated) and heath (shrub dominated), half of them subjected to 4 years of earthworm presence (Lumbricus spp. and Aporrectodea spp.). Within four summers, our earthworm treatment changed plant community composition by increasing graminoid density by, on average, 94% in the heath vegetation and by 49% in the meadow. Rodent winter grazing was more intense on plants growing in soils with earthworms, an effect that coincided with higher N concentrations in plants, indicating a higher palatability. Even though earthworms reduced soil moisture, plant community productivity, as indicated by vegetation greenness (normalized difference vegetation index), was not negatively impacted. We conclude that earthworm-induced changes in plant composition and trophic interactions may fundamentally alter the functioning of tundra ecosystems.

Dynamics of development of juvenile plants in the mountain-tundra belt of the Khibiny Mountains

Germination of seeds and survival of seedlings are important characteristics of the functioning of communities. There are few observations in the literature on the dynamics of seed germination in untouched alpine communities. Severe abiotic environmental factors characteristic of high mountains make it difficult for juvenile plants to take root, and they show high mortality in the first year of life. For 9 years (2011-2019), all juvenile plants were recorded on 5 m2 of the mountain-tundra community of the Khibiny Mountains and their further life was traced. For most plants of the alpine tundra community, low germination and high mortality of juvenile plants in the first year of life were confirmed. Seeds of some species of undisturbed plots, did not germinate during the observation period, most of the rest they did not survive. In species of slightly disturbed places, the number of seedlings was proportional to the number of species in the community, with the exception of species that do not have vegetative propagation. In the latter, seed germination was higher. A surge in the number of seedlings was observed in 2016 and 2019. The surviving individuals did not pass into the generative age state for 7-9 years of observations, which confirms the duration of the life cycle of alpine species.

Changing the Reserves of Green and Lichen Forage Stocks in the Southern Tundra Communities of Yamal from the 1930s to 2017–2019

Changing the Reserves of Green and Lichen Forage Stocks in the Southern Tundra Communities of Yamal from the 1930s to 2017–2019

Changing the Reserves of Green and Lichen Forage Stocks in the Southern Tundra Communities of Yamal from the 1930s to 2017–2019

We compared the reindeer forage stocks at two landfills in the southern part of the Yamal Peninsula for the period from the early 1930s to 2017–2019. Data from [30] was used to characterize the feedstock in the 1930s. Feedstocks in the 1930s and 2017–2019 in plant communities in the basins of the the Erkatayakha and Baidaratayakha rivers were compared in the following vegetation divisions: lichen and shrub tundras; moss and grass tundras; shrub tundra; meadow communities; and bogs. The following hypotheses were tested: (1) the total supply of feed in Yamal decreased since the 1930s; (2) the decrease in stocks affected the lichen component to the greatest extent. Both hypotheses were confirmed. The general changes in the stocks and structure of food in the plant communities of South Yamal over the 85–87 years include delichenization, a decrease in the mass of lichens and the proportion of lichen food. The average stock of lichen fodder from the 1930s to 2017–2019 decreased by 5 times in the communities at the Erkatayakha test site and by 2 times at the Baidaratayakha test site. The mass of green fodder for 85–87 years has not changed. Thus, the change in the masses of economically important components of tundra vegetation over a uniquely long period, almost 90 years, has been characterized.

Carici arctisibiricae–Hylocomietea alaskani – a new class of zonal tundra vegetation

A new class, Carici arctisibiricae–Hylocomietea alaskani class nov. is described for vegetation of the tundra zone on a circumpolar scale. This higher unit in the system of Braun-Blanquet floristic (= floristic-sociological) classification unites the zonal vegetation in the intermediate habitats with respect to the substrate moisture, pH and texture, the snow cover thickness and duration, the depth of seasonal frozen ground thawing, and the growing season length on the interfluves (upland surfaces) within the tundra zone (CAVM subzones B, C, D, E = arctic, typical and southern tundra subzones in Russian zonal subdivision). Communities of the class are distributed on plains north of the tree line on two continents (Eurasia and North America), as well as on the archipelagos (Spitsbergen, Novaya Zemlya, New Siberian Islands, the Canadian Arctic Archipelago) and the large and small islands (Kolguev, Dolgy, Vaygach, Bely, Bolshoy Begichev, Ayon, Wrangel, Greenland) in the Arctic Ocean. The class comprises 3 new orders and 6 alliances. The diagnoses of higher rank units are given. Difficulties in describing and classifying zonal communities due to the specificity of their species composition and horizontal and vertical structure are discussed. The criteria distinguishing the new class from the known ones in the Europe and Asia mountains, in which zonal tundra communities are being placed until now, are presented.

Alpine and Arctic tundra shrub populations show similar ontogenetic growth trends but differing absolute growth rates and lifespan

The majority of terrestrial primary production is performed by plants, the ontogenetic growth trends of which significantly influence biomass and carbon dynamics. Here, we present a study of ontogenetic trends in primary (apical) and secondary (stem thickening) growth of plants in Arctic (Svalbard, Norway) and alpine (Krkonoše, Czechia) populations of the black crowberry (Empetrum nigrum), the dominant plant species of certain tundra communities. The environmental conditions in alpine areas are more favourable for plant growth than those in the High Arctic, where temperatures are lower, there is less precipitation and soils are shallower, among other differences. These differences were clearly reflected in significant distinctions in absolute growth rates and shrub age between the populations under study. However, we found almost no divergence in ontogenetic growth trends between the populations (based on ring width measurements made from the base to the top of plants, known as serial sectioning). In both populations, primary and secondary stem base growth decrease over the course of ontogeny whereas secondary stem top growth and basal area increment increase. No significant differences in the slope of the trends were found in either primary or secondary stem base growth. Trends of the growth ratio between basal area increment and primary growth revealed neither absolute nor relative differences between the populations. Ontogenetic trends in the shrubs analysed were surprisingly stable despite the prominently dissimilar environmental conditions. Empetrum plants have adapted to the different environments by altering their absolute growth rate only. This adaptation has probably also resulted in the different longevity of plants constituting the study populations, confirming the theory that slower-growing plants live longer. Primary growth and secondary stem base growth seem to be more basic characteristics of plant growth compared to basal area increment and secondary growth at the apex because the latter two seem to be dependent on the absolute growth rate.

Predation patterns on the tundra—genetic barcoding of scats from two sympatric fox species

In the Arctic tundra, climate-induced emergence of the red fox ( Vulpes vulpes (Linnaeus, 1758)), a competitor to the Arctic fox ( Vulpes lagopus (Linnaeus, 1758)), is predicted to influence predation patterns of both fox mesopredators. In this study, we (i) identified predator species from scats through an established barcoding approach and (ii) explored the use of a cheap, quick barcoding method of fox feces ( n = 103). We investigated differences in diet between the red fox (predicted generalist predator) and Arctic fox (predicted specialist predator) over 2 years with varying prey abundance. We amplified short DNA fragments (&lt;200 bp) from small rodents, birds and hares. For both predators, there was a high frequency of occurrence of rodents (38%–69%) identifying them as primary prey species and birds as secondary prey species (13%–31%). This demonstrates the strength of a straightforward DNA barcoding method for dietary analyses in sympatric fox predators, with species-level resolution of prey. Barcoding is a promising tool for future dietary studies; however, a few methodological improvements, along with extended sampling, are needed for a more complete assessment of fox predation patterns. Integrating high-resolution dietary analyses have great potential to enhance our understanding of predation patterns in Arctic tundra communities.

Enduring legacy of coal mining on the fungal community in a High Arctic soil after five decades

Mineral extraction is known to affect soil fungi in polar environments, but it is unknown how long these effects persist. Here, by amplifying the internal transcribed spacer regions of rRNA genes in soil fungi, we compared soil fungal community in intact natural tundra with that in a nearby former coal mining area, abandoned 52 years previously, on Svalbard in the High Arctic. Compared with those in intact tundra, soils in the former mining area were more acidic and had lower plant coverage. Despite of similar diversity in the two areas, the fungal community was dominated by Basidiomycota in the intact tundra, but by Ascomycota in the former mining area. Ectomycorrhizal genera formed a major part of the tundra community, but were notably less abundant in the mining area. The principal variation among samples was soil pH. Surprisingly, network connectivity analysis indicated that the fungal community in the former mining area had greater network connectivity than that in the tundra area. Overall, the ecosystem in the former mining area has made only limited recovery towards the natural tundra state even after more than five decades. It is unclear whether the recovery of the fungal community is limited more by the low primary productivity, slow migration of fungi and plants, or slow changes in soil parameters. Our findings emphasize the susceptibility of polar ecosystems to disturbance, given their particularly slow recovery back towards the natural state.

Limited decadal growth of mountain birch saplings has minor impact on surrounding tundra vegetation.

Temperatures over the Arctic region are increasing at three times the rate of the global average. Consequently, Arctic vegetation is changing and trees are encroaching into the tundra. In this study, we examine the establishment and growth of mountain birch (Betula pubescens ssp. tortuosa), which forms the treeline in subarctic Europe, and its impact on community composition across the treeline ecotone nearby Abisko, Sweden. Birch advancement along elevational gradients was studied by comparing data collected in 2016 with data collected 10 and 15 years previously. Species identity, cover, and phylogenetic relatedness were used to assess the impact of birch encroachment on community composition. Our results show that birch occurrence above the treeline did not affect plant community composition, probably owing to the observed lack of significant growth due to herbivore browsing, nitrogen limitation, or a reduction in snow cover. Independent of birch performance, the tundra community structure shifted toward a novel community dissimilar from the forest plant community found below the treeline. Taken together, our findings are explained by species‐specific responses to climate change, rather than by a linear forest advance. Future treeline advancements are likely more restricted than previously expected.