FEATURES OF THE RADIAL GROWTH OF SHRUBS BETULA NANA AND SALIX LANATA ON VARIOUS LANDSCAPE ELEMENTS IN THE SOUTHERN TUNDRA OF YAMAL

Tundra communities are widespread in the northern part of Russia, in particular on the Yamal Peninsula in the registration of Siberia, where research was carried out. For the study, we used plants of the species Betula nana and Salix lanata, these species are among the most common in the southern tundra of Yamal. Sampling sites were located on various morphological elements of the relief with the identification of patterns in the distribution of natural resources that determine the radial growth of the trunks of Betula nana and Salix lanata. At each site, at least 30 samples of each species were taken to obtain a sufficient sample. The sampling sites were located on different morpholog-ical parts of the relief. In the course of the study, general growth trends are highlighted, as well as absolute values of growth for 5 years. This age corresponds to the minimum age of the selected plants. As a result, data were obtained on the distribution and growth characteristics of Betula nana and Salix lanata shrubs along the relief profile; the most and least favourable areas of the profile for the growth of shrubs were identified. To compare the general trends of radial growth, a faster slowdown in growth was found in Betula nana. In addition, it was found that the species Salix lanata has a stronger effect on mechanical impact (winter road).

Genetic diversity of Betula nana in Sweden and conservation implications for protection of relict Polish populations

The natural range of the dwarf birch (Betula nana L.) includes the boreal, subarctic and arctic regions of Europe, Asia and North America, where it is relatively common. In Poland, it is a relict species occurring in fragmented populations. Using the random amplification of polymorphic DNA (RAPD) technique, we investigated the genetic diversity of the four Swedish populations representing a part of the continuous range of dwarf birch. With the knowledge of the level of genetic diversity of a population from a continuous distribution, we can assess the genetic status of polish populations and answer the question if habitat fragmentation and a decrease in population size lead to a loss in genetic diversity. Knowledge of genetic diversity is important for species conservation, especially to predict their ability to respond to environmental pressures. We found that the populations Abisko, Malbo, Gällivare and Storlien, which are located at the edge of the natural range of B. nana and occupy different habitats, are genetically diverse to varying degrees. The northern populations from Abisko and Gällivare showed a lower level of genetic polymorphism than the population from Malbo, the southernmost site of dwarf birch in Sweden. The data presented indicate higher genetic diversity existed within populations, whereas genetic differentiation between populations was lower. The high level of genetic differentiation within B. nana populations that were analysed in the present study may be explained by a limited capacity for dispersal among populations via both pollen and seeds. We found that the level of genetic diversity in one of the Polish populations of B. nana is comparable to that in areas in Scandinavia where populations are large and continuous. Based on these studies, we conclude that the “Linje” population has sufficient genetic resources.

Effects of experimental warming on Betula nana epidermal cell growth tested over its maximum climatological growth range

Numerous long-term, free-air plant growth facilities currently explore vegetation responses to the ongoing climate change in northern latitudes. Open top chamber (OTC) experiments as well as the experimental set-ups with active warming focus on many facets of plant growth and performance, but information on morphological alterations of plant cells is still scarce. Here we compare the effects of in-situ warming on leaf epidermal cell expansion in dwarf birch, Betula nana in Finland, Greenland, and Poland. The localities of the three in-situ warming experiments represent contrasting regions of B. nana distribution, with the sites in Finland and Greenland representing the current main distribution in low and high Arctic, respectively, and the continental site in Poland as a B. nana relict Holocene microrefugium. We quantified the epidermal cell lateral expansion by microscopic analysis of B. nana leaf cuticles. The leaves were produced in paired experimental treatment plots with either artificial warming or ambient temperature. At all localities, the leaves were collected in two years at the end of the growing season to facilitate between-site and within-site comparison. The measured parameters included the epidermal cell area and circumference, and using these, the degree of cell wall undulation was calculated as an Undulation Index (UI). We found enhanced leaf epidermal cell expansion under experimental warming, except for the extremely low temperature Greenland site where no significant difference occurred between the treatments. These results demonstrate a strong response of leaf growth at individual cell level to growing season temperature, but also suggest that in harsh conditions other environmental factors may limit this response. Our results provide evidence of the relevance of climate warming for plant leaf maturation and underpin the importance of studies covering large geographical scales.

Lichens buffer tundra microclimate more than the expanding shrub Betula nana

Background and Aims In tundra systems, soil-borne lichens are often the dominant groundcover organisms, and act to buffer microclimate extremes within or at the surface of the soil. However, shrubs are currently expanding across tundra systems, potentially causing major shifts in the microclimate landscape. Methods Here, we compared soil temperature and moisture underneath the dwarf birch Betula nana and seven abundant lichen species in subalpine Norway. We also examined mixtures of lichens and dwarf birch, an intermediate phase of shrubification, and measured several functional traits relating to microclimate. Key Results We found that all lichen species strongly buffered the daily temperature range, on average reducing maximum temperatures by 6.9 °C (± 0.7 SD) and increasing minimum temperatures by 1.0 °C (± 0.2 SD) during summer. The dwarf birch had a much weaker effect (maximum reduced by 2.4 °C ± 5.0 SD and minimum raised by 0.2 °C ± 0.9 SD). In species mixtures, the lichen effect predominated, affecting temperature extremes by more than would be expected from their abundance. Lichens also tended to reduce soil moisture, which could be explained by their ability to intercept rainfall. Our trait measurements under laboratory conditions suggest that, on average, lichens can completely absorb a 4.09 mm (± 1.81 SD) rainfall event, which might be an underappreciated part of lichen-vascular plant competition in areas where summer rainfall events are small. Conclusions In the context of shrubification across tundra systems, our findings suggest that lichens will continue to have a large effect on microclimate until they are fully excluded, at which point microclimate extremes will increase greatly.

Lateglacial and Holocene floras and faunas from the Salpetermosen area, north-east Sjælland, Denmark

The Salpetermosen area in north-east Sjælland, Denmark, was deglaciated about 18 000 to 17 000 years ago. Melting of bodies of stagnant glacier ice led to the for-mation of kettle holes, which contain Lateglacial and Holocene sediments with remains of plants and animals that provide information on the past flora and fauna of the area. During the Allerød period, open forests with Betula pubescens (downy birch) characterised the area, the flora included light-demanding species such as Arctostaphylos uva-ursi (bearberry), Empetrum nigrum (crowberry) and rare Populus tremula (aspen), Betula nana (dwarf birch) and Rubus saxatilis (stone bramble), as well as the thermophilous swamp plant Oenanthe aquatica (fine-leaved water dropwort). During the Younger Dryas, the vegetation was characterised by dwarf-shrub heaths dominated by Betula nana, but including Dryas octopetala (mountain avens), Salix herbacea (least willow), Arctostaphylos alpina (alpine bearberry,) and rare Betula pube-scens, as well as the thermophilous plants Urtica dioeca (stinging nettle) and Lychnis flos-cuculi (ragged robin). The Early Holocene forests were dominated by Betula pubescens, Populus tremula and Pinus sylvestris (scots pine), but included rare Betula nana. Alnus glutinosa (alder) arrived at c. 10 000 cal. years BP. The calciphilous sedge Cladium mariscus (fen-sedge) and the macrolimnophyte Najas marina (spiny naiad) were common. The Late Holocene flora included the acidophilous plant Scheuchzeria palustris (rannoch-rush).

Види рослин і лишайників Кий-острова в Гербарії Національного лісотехнічного університету України (LWFU)

Кий-острів, що розташований в Онезькій затоці Білого моря (географічні координати 64°00′ п. ш., 37°53′ с. д.) – це виступ гранітної плити, яка залягає на незначній глибині і виходить на поверхню моря у вигляді скель. Геоморфологічні та кліматичні особливості острова, близькість до Північного полярного кола та Арктичної області, зумовили формування на ньому своєрідних природних комплексів, де переважають соснові ліси. Виконані в липні 1984 р. серії описів лісових біоценозів острова дали змогу встановити як основні типи цих лісів (сосняк лишайниковый скальный, сосняк лишайниковый каменистый, сосняк лишайниковый багульниково-вересковый на вершинах сельг [Kucherov, Zverev, 2012; Rupestrian landscapes…, 2008; Rysin, 1975]), так і відповідні їм типи асоціацій (Pinetum cladinosum petraeum, Myrtillus-Calluna-Cladina-Typ, Pinetum uliginosi-vaccinioso-ledosum). Наведений перелік домінантних видів рослин і лишайників нижніх ярусів лісових біоценозів демонструє наявність у їх складі характерних представників бореальної та гіпоарктичної флори. Найбільша частина з них – це класичні бореальні види: Andromeda polifolia L., Arctostaphylos uva-ursi (L.) Spreng., Chamaedaphne calyculata (L.) Moench, Ledum palustre L., Linnaea borealis L., Nardus stricta L. та інші. На другій позиції знаходяться гіпоарктичні види, серед яких Betula nana L., Rubus arcticus L., Rubus chamaemorus L., Cornus suecica L. На поверхнях скель високу частку складають представники відділу Lichenomycota – характерні елементи північних та південних лишайникових тундр, а саме: Cladonia stellaris (Opiz) Pouzar & Vězda, Cladonia sylvatica (L.) Hoffm., Cladonia rangiferina (L.) Weber ex F.H.Wigg., Cetraria islandica (L.) Ach., Peltigera aphthosa (L.) Willd. Зібраний гербарний матеріал (45 зразків 16-ти таксонів) достатньою мірою відображає найбільш характерні риси біоти скельних сосняків Кий-острова та являє собою єдину колекцію видів з північної тайги європейської частини Росії в Гербарії Національного лісотехнічного університету України, який офіційно зареєстрований в міжнародних базах даних під акронімом LWFU.

Current palynological pattern of steppe-tundra at the Altai highland depressions

<p>The landscape and climate research in Altai highlands were carried out in 2018 – 2019. The results of our investigation at the Khindiktig-Khol’ Lake Basin (Mongun-Taiga massif, Tuvan Republic) and Bertek depression (plateau Ukok, Altai Republic) are presented. In frame of study 75 samples (56 – subfossil, 13 flower buds, 6 recent) were collected for pollen analysis. Two key questions are to define the possible steppe-tundra palynological pattern based on project BIOME 6000 relying on steppe and tundra data and to compare palynological pattern with the subfossil data from Altai expeditions (2018-2019). The study was financially supported by Russian Foundation for Basic Research (RFBR) (Grant 18-05-00860).</p><p>Within international investigation project BIOME 6000 the palynological patterns of tundra and steppe vegetation were composed (Bigelow et al., 2003). Tundra is characterized by several biomes, such as low- and high-shrub tundra (SHRU; <em>Alnus fruticosa</em>, <em>Betula nana</em>, <em>Salix vestita</em>, <em>Eriophorum</em>, <em>Sphagnum</em>), erect dwarf-shrub tundra (DWAR; <em>Betula nana</em>, <em>Salix herbacea</em>, <em>Cassiope</em>, <em>Empetrum</em>, <em>Vaccinium</em>, Poaceae, Cyperaceae), prostrate dwarf-shrub tundra (PROS; <em>Salix herbacea</em>, <em>Dryas</em>, <em>Pedicularis</em>, Asteraceae, Caryophyllaceae, Poaceae, true mosses), cushion-forb tundra (CUSH; <em>Draba</em>, <em>Papaver</em>, Caryophyllaceae, Saxifragaceae, lichens, true mosses) and graminoid and forb tundra (DRYT; <em>Artemisia</em>, <em>Kobresia</em>, Asteraceae, Brassicaceae, Caryophyllaceae, Poaceae, true mosses). Steppe is described by two biomes: temperate grassland (STEP; Asteraceae, Chenopodiaceae, Liliaceae, grasses) and temperate xerophytic shrubland (STEP; <em>Artemisia</em>, <em>Chrysothamnus</em>, <em>Hippophae</em>, <em>Purshia</em>, grasses). In spite of the absence of steppe-tundra palynological pattern, it may include the pollen data both from steppe (<em>Artemisia</em>, <em>Chrisotamnus</em>, <em>Hippophae</em>, <em>Kobresia</em>, <em>Purshia</em>, Brassicaceae, Chenopodiaceae) and tundra (<em>Alnus fruticosa</em>, <em>Betula nana</em>, <em>Salix herbacea</em>, <em>Cassiope</em>, <em>Draba</em>, <em>Dryas</em>, <em>Empetrum</em>, <em>Eriophorum</em>, <em>Papaver</em>, <em>Pedicularis</em>, <em>Vaccinium</em>, Cyperaceae, Saxifragaceae, <em>Sphagnum</em>, lichens) patterns.</p><p>In pollen spectra of western Mongun-Taiga trees mean values vary from 36.4% to 45.4%. The predominance of dwarf birch (<em>Betula nana</em>) dust with the average number 28.7% is identified. As for the Bertek depression, the values change from 36.4% in Muzdy-Bulak to 59.3% in Argamdzhi (2019). Data from subfossil samples in 2018 show the dominance of Betula nana pollen (23.0%), whereas in 2019 it is indicated the significant and constant wind drift of <em>Betula sect. Albae</em> particles (average number – 36.7%) through the massif valleys to the region of sample collection.</p><p>In pollen spectra of herbs in Mongun-Taiga region mean value equals 57.9%, whereas at the Bertek depression the values differ from 62.8% (2018) to 37.3% (2019). Those spectra mostly consist of dust samples, such as <em>Carex</em>, Cyperaceae and Poaceae. Asteraceae, Caryophyllaceae, Chenopodiaceae and Fabaceae are also present in both regions.</p><p><em>Artemisia</em> and Chenopodiaceae are the prime indicators of steppe conditions. The vegetation description of the landscapes, where the subfossil samples were collected, proves those conditions. Both vegetation and pollen data are also correlated with the DRYT and STEP biomes from project BIOME 6000. The only difference is that <em>Artemisia</em> prevails at the steppe sites of central and eastern part of Bertek depression, whereas Chenopodiaceae is mostly found within the coexistence of tundra and steppe cenoses in Khindiktig-Khol’ area and western part of Bertek depression.</p>

Microrefugia - limiting factors and unique synergy of environment

<p>Peatlands are a very important ecosystem which are characterized by distinctive vegetation, hydrology, and local climate. In the last decades, much effort was made a better understanding of microrefugia and their importance. Nevertheless, we still have little knowledge about the histories of the refugia. In the day of rapid climate change and increasing anthropogenic pressure, knowledge about the history of sites that represent a refugium of flora or fauna is a key aspect. The aim of this study is reconstructing the history of the glacial relict Betula nana in northern Poland located far from the southern range of its natural distribution. We suppose that the persistence of Betula nana is driven by a) the morphology and geology of the catchment, b) the maintenance of open vegetation on the peatland surface and c) exceptional microclimatic and hydrological conditions. Here, based on recent eco-hydrological monitoring and long-term palaeoecological proxy we try to be understated postglacial refugia of Betula nana from Central Europe (Linje mire). Detailed research was carried out on the peat profile using pollen analysis, to reconstruct the presence of open habitat on the mire during the Holocene. Pollen and macrofossils analysis revealed a continuous presence of Betula nana in the postglacial history of the peatland. Palaeoecological results show the variable situation of the Betula nana population in the peatland over the past 12 ka, indicating a strong relationship between paleohydrology and changes in the occurrence of this species. Our results of 12 years of local monitoring indicated that the mire is characterized by specific local climate and diverse water table depth. A synergy of local relief, microclimates, hydrology, and geology of the catchment affects the Betula nana population during the post-glacial history.</p>