Dominance of coniferous and broadleaved trees drives bacterial associations with boreal feather mosses

The composition of ecologically important moss-associated bacterial communities seems to be mainly driven by host species, but may also be shaped by environmental conditions related with tree-canopy dominance. The moss phyllosphere has been studied in coniferous forests while broadleaf forests remain understudied. To determine if host species or environmental conditions defined by tree-canopy dominance drives the bacterial diversity in the moss phyllosphere, we used 16S rRNA gene amplicon sequencing to quantify changes in bacterial communities as a function of host species (Pleurozium schreberi and Ptilium crista-castrensis) and forest type (coniferous black spruce versus deciduous broadleaf trembling aspen) in eastern Canada. Forest type, not host species, was the main factor affecting moss phyllosphere bacterial community composition, though the interaction of both variables was significant. Bacterial α-diversity was highest in spruce forests, while there was greater turnover (β-diversity) and higher γ-diversity in aspen forests. Unexpectedly, Cyanobacteria were much more relatively abundant in aspen than in spruce forests, with the bacterial family Nostocaceae (Cyanobacteria) differing the most between both forest types. Our results suggest that the increasing change in dominance from coniferous to broadleaf trees due to natural and anthropic disturbances is likely to affect the composition of moss-associated bacteria in boreal forests.

SUCCESSION DYNAMICS OF NATIVE SPRUCE FORESTS OF DIFFERENT AGES IN EUROPEAN RUSSIA

Relevance. The article discusses various options for assigning forest biogeocenoses to a certain dynamic position in the successional field of their development. The proposed method for dynamic assessment of the position of forest creates the possibility of assessing the total movement of tree volumes in the age generations of the age range of the forest biogeocenosis the possibility of analyzing the past changes in the age structure of the biogeocenosis and predicting its future development for a very distant future. Material and methods. The objects of research are native virgin spruce biogeocenoses of different ages in the northern taiga of the Kandalaksha forestry enterprise of the Nyamozersky forestry of the Murmansk region, the Severodvinsky forestry enterprise of the Arkhangelsk region; middle taiga spruce forests of the Vepssky forest reserve, Leningrad region. and the tract “Atleka” of the Andomsky forestry of the Vologda region; southern taiga spruce forests of the Kologrivsky forest reserve Kostroma region and the Central Forest Biosphere Reserve in the Tver region. The author studied the features of the structures of the age series of spruce forests, the most typical and productive types of growing conditions for spruce. Results and conclusions. All represented forest communities have different ratios of the number and volume of trees in the age generations of the age series and, as a consequence, different positions in the successional dynamics of development. Wood-destroying fungi of the biotrophic complex, as an endogenous structure of the forest community, actively participates in the dynamic processes of its development at all stages of its successional movement. The infection of trees by fungi of this complex increases from the last generations to the first to the maximum values in the oldest trees of the first generation. The dynamic position of the indigenous virgin forest community of different ages can be described with a wider range of assessments of the dynamics of its development in retrospect and perspective in terms of the ratio of quantitative and volumetric indicators of age generations of age series than in terms of the current structure of the age series. When assessing the successional stage of the forest community, it is necessary to take into account the quantity (volumes) and structure of the deadwood.

Phytocoenotical behaviour of boreal plant species in broadleaved-forest zone communities

Phytocoenotic behaviour of 11 species of boreal vascular plants and mosses is analyzed within the broadleaved-forest zone in comparison with that in different subzones of the boreal-forest zone, based upon the set of 1417 relevés made in European Russia in 1996–2017. The significance of differences in species cover is estimated by means of the one-way ANOVA. The cover of species like Vaccinium myrtillus, V. vitis-idaea, andHylocomium splendens in broadleaved / spruce forests of zonal types is constantly decreasing southwards. On the contrary, the cover of Luzula pilosain Scots pine forests and Pleurozium schreberi and Dicranum polysetum in paludified Norway spruce forests is subject to southward increase. Finally, Oxalis acetosella and Equisetum sylvaticum demonstrate maximae of their cover in forests of zonal types in the southern-boreal and hemiboreal subzones. The dark-coniferous boreal forest “cortege” of species is breaking down into several different floristic elements in the broadleaved-forest zone. These are: “vaccinietal” species p. p. sensu Yu. D. Kleopov (like Vaccinium myrtillus), “quasi-boreal” species sensu V. B. Sochava (Oxalis acetosella, Maianthemum bifolium, Trientalis europaea), hygromesophytes with aged areas (Equisetum sylvaticum), associated species with European-Ancient-Mediterranean nemoral (Luzula pilosa) or East-Asian boreal-montane (Rubus saxatilis) origins. Phytocoenotical behaviour of species is not always different in the intrazonal and the zonal community types but is rather similar in many cases like those of Vaccinium vitis-idaea and Equisetum sylvaticum. The more distinct differences in species positions are found in the extrazonal communities. The statistically proved differences are lacking in phytocoenotical behaviour of Maianthemum bifolium and Trientalis europaea in different zones and subzones due to either florogenetical, or purely methodical reasons, the latter connected with low abundance but high constancy of these species. Disintegration of vegetation “corteges” and individualization of coenotic patterns of species previously growing together are usually observed at the climatically determined (zonal / subzonal or altitudinal) distribution limits.

Diversity of lichens, mosses and vascular plants in the paludified herb-rich spruce forests of the Pinego-Mezen watershed (Arkhangelsk Region)

The paludified herb-rich spruce forests of the Pinego-Mezen watershed are characterized by a high speciesand coenotical diversity. The habitat type (floodplain, stream valley, mire margin) is the main compositional gradientfor vascular plant and moss diversity. The density, basal area and proportion of spruce and deciduous species in thetree stand are less significant. The main compositional gradient of the lichen diversity is the tree stand structure, whichprovides the availability and quality of the substrate for the epiphytic and epixilic lichens that prevail in such communities.The gradient of paludified herb-rich spruce forests from floodplain habitat to mire margins is less significant for thecomposition of lichen flora.

Importance of lichen and moss litters to soil carbon storage in black spruce forests on permafrost

Aims Climate warming is predicted to increase permafrost degradation and soil carbon (C) loss, while changes in microrelief and vegetation cover can also influence soil C storage at local scale. Black spruce forests develop lichen/moss-covered organic mounds on permafrost. Recalcitrance of lichen and moss litters, as well as cold climate, is hypothesized to increase C storage in hummocky soils. Methods We compared the decomposition rates of lichen and moss litters, spruce root litter, and cellulose at hummocky clayey soils, non-hummocky clayey soils, and non-hummocky sandy soils in northwest Canadian subarctic. Results Lichen/moss-covered hummocky clayey soils display greater C stocks than non-hummocky clayey and sandy soils. Lichen and moss litters decomposed more slowly than did spruce root litter and cellulose. Recalcitrant litter inputs of lichen and moss contribute to greater C stocks of hummocky clayey soils, compared to non-hummocky clayey and sandy soils. Lower temperature dependency of lichen and moss litter decomposition, compared to vascular plant litter, suggests stronger resistance of lichen and moss litters to decomposition. Conclusion Permafrost degradation by climate warming would reduce hummocky microrelief covered by lichen and moss, major contributors to soil C, and decrease the high potential for C storage of black spruce forests on permafrost.

The Impact of Local Climate Change on Radial Picea abies Growth: A Case Study in Natural Mountain Spruce Stand and Low-Lying Spruce Monoculture

Picea abies L. Karst is undeniably one of the most important tree species growing in Slovakia. In addition to natural mountain spruce forests, monocultures planted in lower areas are also quite common. In this article, we analyze the climate–growth response differences between these two types of spruce stands in the context of local climate change consequences. The study area representing natural mountain spruce forests is located under Osobitá Mt. (Tatra Mountains, Slovakia), while the analyzed low-lying planted monoculture is situated near Biely kríž (Malé Karpaty Mountains, Slovakia). Temporal variation of the dendroclimatological relationships was expressed by the running Spearman correlation coefficient during the observed period 1961–2018. The results showed crucial differences in the dendroclimatological relationships between the selected study areas. For the natural mountain spruce stand, consistent, weak, and positive correlations to the temperature variables were typical, with negative relationships to precipitation during the growing season. In this case, the negative impact of a recent temperature rise was limited. In contrast, the monoculture reacted to the temperature variation during the growing season with fluctuations, while in the case of precipitation, almost no dependence was found. Such incoherency may be a consequence of worsened health conditions, as well as insufficient resiliency to climate-driven stress. The importance of this paper is in its wide applicability, mainly in forestry.