Treeline Research Articles

Decomposing niche components reveals simultaneous effects of opposite deterministic processes structuring alpine small mammal assembly

IntroductionSpecies distribution in alpine areas is constrained by multiple abiotic and biotic stressors. This leads to discrepant assembly patterns between different locations and study objects as opposite niche-based processes—limiting similarity and habitat filtering—simultaneously structure communities, masking overall patterns. We aimed to address how these processes structure small mammal communities in the alpine tree line transition zone, one of the most distinct vegetation transitions between alpine and montane habitats.MethodsWe compiled a dataset of species checklist, phylogeny, and functional traits from field collection and published sources spanning 18 mountains in southwest China. We first examined hypothetical niche-based processes with frequently used phylogenetic and trait approaches using this dataset. The species traits were decomposed into different niche components to explore the respective effects of specific stressors. Indices representing evolutionary history, trait space, and pairwise species distance were estimated and compared with null model expectations. Linear mixed-effect models were used to assess the association patterns between diversity indices and elevation.ResultsThe results indicated that phylogenetic and functional richness were positively correlated with species richness. In contrast, distance-based indices were either negatively or weakly positively correlated with species richness. Null model analyses suggested no evidence of non-random phylogenetic or overall trait patterns. However, the resource acquisition niche tended to be more overdispersed (positive slopes), while the habitat affinity niche tended to be more clustered (negative slopes) beyond the high elevation tree line.DiscussionThese findings show that opposite niche-based processes simultaneously structure small mammal communities in alpine areas. Overall, the present study provides vital insights into the complexity of assembly processes in these habitats. It also highlights the importance of relating relevant traits to distinguish the influences of specific abiotic and biotic stressors.

Timberline and treeline dynamics: Pinus sibirica trees move

In the context of climate change, one of the important issues in assessing the state of mountain forest ecosystems is the study of the upward movement of the tree line (tree line) and forest line (timberline). To determine the potential of a particular species when moving up the slope, the functional characteristics of the needles are of great importance. This paper considers changes in the pigment composition of needles and the depth of winter dormancy of two coniferous species Pinus sibirica and Abies sibirica growing in the area of the Ergaki Ridge of the Western Sayan.

Редкие сообщества асс. Molinio caeruleae–Trollietum europaei ass. nov. в Хибинских горах (Кольский полуостров)

Mountain tundra meadows with dominance of Molinia caerulea were found in the Khibiny Mountains (Kola Peninsula) (Fig. 1) and described based on the Braun-Blanquet approach. Ass. Molinio caeruleae–Trollietum europaei ass. nov. (Fig. 2, Table, holotypus — relevé 7, 67.611327° N, 33.61316° E; 530 m a. s. l.) is ascribed to the alliance Potentillo–Polygonion vivipari Nordh. 1937, order Epilobio lactiflori–Geranietalia sylvatici Michl, Dengler et Huck 2010, and class Mulgedio-Aconitetea Hadač et Klika in Klika et Hadač 1944. The diagnostic species are Achillea apiculata, Dianthus superbus, Festuca ovina, Geranium sylvaticum, Melica nutans, Molinia caerulea, Trollius europaeus, Vaccinium myrtillus. The undergrowth layer is sparse and composed with Betula nana, Cotoneaster cinnabarinus, Juniperus sibirica. In the upper layer (about 0.5–0.8 m high) most abundant are tall herbs (Molinia caerulea, Dianthus superbus, Geranium sylvaticum, Trollius europaeus and Cirsium heterophyllum). Lower layer (0.1–0.3 m high) is composed with low herbs (Anthoxanthum alpinum, Bistorta vivipara, Epilobium lactiflorum, E. hornemannii, Festuca ovina, Veronica alpina, Viola biflora, V. canina subsp. montana) and dwarf shrubs (Empetrum hermaphroditum, V. uliginosum, V. myrtillus). Ground layer is prostrate and consists of Sciuro-hypnum starkei, S. reflexum, Sanionia uncinata, Bryum spp. and Polytrichum spp. Association comunities occupy rather large areas and are located above the tree line and in the lower part of the mountain-tundra belt, at 410–540 m a. s. l., on well-moistened steep (45–50°) rocky slopes, exposed to southwest and southeast, near groundwater outlets or in places of late snowmelt. Probably the association is of relic nature and marks the tree line of the warmest Holocene period. Rich of species, including Red Data Book Cotoneaster cinnabarinus, Epilobium lactiflorum, Veronica fruticans, it is a value habitat type «E2.3 Mountain hay meadow» in the Kola Peninsula.

Distribution, population status, habitats, and conservation of Lesser Spotted Eagle in Bulgaria

The Lesser Spotted Eagle (Aquila [Clanga] pomarina) is a territorial raptor, distributed from Baltic region to Anatolia and Caucasus. Bulgaria is a part of the southern limit of the species distribution range. Since 2014, intensive field research in Eastern and Central Bulgaria identified an abundant and stable population of the species. For the period 2014–2023, 167 different active nests were found, and more than 450 occupied territories were mapped in Eastern and Central Bulgaria. Thus, the current population estimate is at least 1,000 breeding pairs. About 60% of the breeding population of the Lesser Spotted Eagle was situated in SPAs, but only 2.3% was located within Nature reserves, indicating insufficient protection of the species. The increasing anthropogenic pressure, mainly in terms of dramatic alteration of the species foraging and breeding habitats, and the lack of efficient legal protection pose a serious risk to the future of the Lesser Spotted Eagle in this part of the species distribution range. Most of the nests were situated at the edge of a forest, 19% were found in tree lines along the rivers, and only 2% were situated in single trees. The habitats varied from small forests and grasslands and significant percent of arable land to forests, small patches of arable land, and shrubs (less than 1%), as well as typical mosaic landscape with patches of cultivated crops, grasslands, and forest areas. The major threats to the habitats include plowing of grasslands, overgrowth of grasslands, forest management gaps, disturbance, construction of wind farms and solar parks, natural fires. Analysis of prey (n=523) from collected food remains (n=45 nests) shows that the main prey is Voles (Arvicolinae), accounting for 42.64% of all prey, followed by the Northern White-breasted Hedgehog (Erinaceus roumanicus), 13%. A parallel survey of the diet using photo traps (n=24 nests) and examining 141,985 photographs identified 1,357 different prey items. The results demonstrate again the dominant role of Voles (36%) as a main food resource, but followed by lizards (Lacertidae), 30%. The main conservation activities undertaken for the species in Bulgaria include appling biodiversity-friendly forest practices, improving breeding and foraging habitats, satellite tracking, restoration of breeding habitats through forest planting, insulation of hazardous electric poles, implementation of educational programs with children and local communities.

The Kriviches: Etymology, Localization, and Type of Identity

The article analyzes the data from a set of written sources on the early medieval community of Kriviches. These data unequivocally indicate that the Kriviches were the carriers of the Slavic language. Their place of habitation is specified — within the limits of the Oka forest, it is shown that they originally inhabited the cities of Smolensk and Polotsk. The time when their community existed — from the middle of the 10th century to the beginning of the 12th century — is also specified. It is concluded that the Kriviches were one of the Slavic communities, evidently serving (guides and boatmen on drag) the system of trade and communication routes between the upper reaches of the Volga, Dnieper and Western Dvina rivers. There are also arguments in favour of the fact that the inhabitants of the Polotsk land continued to be considered Kriviches in the 12th century, and perhaps even later — until the beginning of the 14th century.

Efeito do desbaste das árvores de eucalipto sobre rendimento da soja em sistemas de integração lavoura-pecuária-floresta

ABSTRACT: The aim of the study was to evaluate the effects of integrated crop-livestock-forestry (ICLF) systems and the thinning of eucalyptus trees on the agronomical performance of soybean. Treatments consisted of cultivation under: crops under full sunlight (CFS) conditions; ICLF with triple-row tree configuration (ICLFT) in which trees were submitted to selective thinning in the fifth year after planting through removal of 50% of trees while maintaining triple-row bands; and ICLF with single-row tree band configuration (ICLFS) in which the lateral rows of the triple-row tree bands were subjected to systematic thinning at the fourth year after planting. The physiological and agronomical variables of the soybean crop were evaluated at the R5 and R8 reproductive stages during the eighth harvesting season (2018/2019). Soybean sampling was carried out at five random positions in the CFS and in four transects at distances of 3, 6, 10 and 15 m from the tree bands in both the north and south faces of the ICLF systems. There were no differences between soybean grown under the ICLF and CFS systems with respect to specific leaf area, plant density, lodging index and mass of a thousand grains. However, the ICLF increased dry leaf mass and leaf area index and reduced soybean plant heights. Soybean productivity was reduced by 26% in ICLF-T and 14% in ICLF-S, that is, a 12% reduction in the productivity loss with systematic thinning. It is concluded that ICLF reduces soybean productivity in the effective grain production area of the system, regardless of the degree of thinning, although systematic thinning by removing the lateral tree lines to conversion of triple-rows into single-rows minimizes the loss of soybean grain yield.

Procena biotičke ugroženosti gradskog zelenila - studija slučaja u parku Stromovka, Češke Budejovice

Urban greenery, consisting of tree lines, parks and park forests, plays an important role in improving the aesthetics and general well-being of the urban environment. This study focuses on Stromovka Park in České Budejovice and examines the health status of various tree species. The research spans the period from 2021 to 2022 and uses the route method to monitor the occurrence of biotic pests and pathogens, especially mites and insects. Several economically important organisms were identified in the study, including Aceria fraxiniflora (Felt, 1906), Byctiscus betulae (Linnaeus, 1758), Curculio glandium Marsham, 1802, Eriophyes inangulis Nalepa, 1919, Fomes fomentarius (L.) Fr. 1849, Halyomorpha halys (Stål, 1855), Ips typographus (Linnaeus, 1758), Lymantria dispar (Linnaeus, 1758), Loranthus europaeus Jacq., Oxycarenus lavaterae (Fabricius, 1787), Pemphigus spyrothecae Passerini, 1856, Phyllonorycter issikii (Kumata, 1963), Polygraphus poligraphus (Linnaeus, 1758), Prociphilus fraxini (Fabricius, 1777), Rhytisma acerinum Schwein., (1832), Sacchiphantes viridis (Ratzeburg, 1843) and Tetraneura ulmi (Linnaeus, 1758). While most of these organisms showed normal, natural abundance values, increased values were observed in A. fraxiniflora, E. inangulis and O. lavaterae. The application of holistic plant protection principles, from proper cultivation and species selection to monitoring and control measures, remains crucial for maintaining the vitality and longevity of urban green spaces exposed to various biotic and abiotic stress factors.

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.

Vegetational parameters and timing of capsule ripening of a high altitude Rhododendron (R. campanulatum) in Central Himalaya

R.campanulatum forms krummholz close to the tree line in alpine areas. In the present study it is considered as a tree species and we concentrated our attention on capsule maturation timing and documentation of phenological events of this species which is expanding and regenerating at high altitudes. This species is relatively less studied in relation to its phenology, seed physical parameters and germination. The study was concentrated in a 5 ha area located between 3200 and 3450 m elevation in two consecutive years (2016- 2017). The overhead forest canopy was dominated by Quercus semecarpifolia towards the upper side and by Aesculus indica on the lower side. In R. campanulatum flowering started from 2nd and 3rd week of April and maximum flowering was observed between 1st and 4th week of June. Capsule formation started from 3rd and 4th week of June to 4th week of July and maturity of capsule was in the month of December to January. The colour of capsules was initially green and finally turned brown. The capsules of R. campanulatum were collected at ten days interval from the month of December up to the availability of capsules from selected sites. The number of seeds per capsule varied between 1012 and 1136. Germination was counted when visible radical had developed. The germination was maximum 42.5 ± 4.2 % at 26.3 ± 2 % moisture content. Fresh weight of capsule correlated positively with date of collection (r = 0.827; P<0.01).

The effects of biophysical and anthropogenic factors on the recent upper forest‐cover upward shift in the Romanian Carpathians

AbstractAimTo estimate the effects of environmental and human drivers on upper forest‐cover upward shift over the period 1945–2018.LocationRomanian Carpathians.MethodsUsing historical topographic maps and high‐resolution Sentinel‐2A satellite images, we delineated the location of the upper forest‐cover limit in 1945 and 2018 to obtain a binary raster with the “forest gains” and “no‐forest gains” for 1945–2018. The maps were overlapped over 12 independent variables to estimate how they affected the recent upper forest‐cover upward shift, and to predict its probability of expansion in the near future. To achieve this, logistic regression models were applied and then integrated into the GIS spatial analysis.ResultsForest gains of almost 35,000 ha have been detected at the upper forest limit in the study sites, leading to an average upward movement of 30 m (0.5 m per year), mainly at the altitudinal bands between 1,400 and 1,800 m a.s.l. (72%); only 9.7% of the gain was detected above the estimated potential climatic limit. The process was significantly inversely related to elevation (−17.3 ≤ β ≤ −5.7, p < 0.01), slope aspect (−1.5 ≤ β ≤ −0.4, p < 0.01), sheepfold numbers (−18.1 ≤ β ≤ −0.7, p < 0.01), and sheep (−18.3 ≤ β ≤ −0.6, p < 0.01) and cattle (−16.4 ≤ β ≤ −0.8, p < 0.01) populations. Strong direct effects were found for the slope angle (1.3 ≤ β ≤ 10.6, p < 0.01) and distance to sheepfolds (0.5 ≤ β ≤ 12.8, p < 0.01). A low contribution was indicated for the trend in mean air temperature (−1.1 ≤ β ≤ 4.3, p < 0.01), growing season length (−2.1 ≤ β ≤ 5.1, p < 0.01) and protective measures (−1.1 ≤ β ≤ 2.4, p < 0.01, for national parks; −1.8 ≤ β ≤ 1.2, p < 0.01, for natural parks).ConclusionsThe analysis demonstrated that decreased land‐use intensity and, in particular, declining traditional practices were the foremost mechanisms of the recent upper forest‐cover upward shift, whereas the effect of climate warming remains not so obvious.

Find of a Bronze Macehead from the Kraków-Częstochowa Upland in Poland

The Upper Silesian Museum in Bytom houses an interesting find of a macehead discovered in the Michałowiec nature reserve (commonly known as the Michałowiec/Michałówka Forest). The reserve is located on the northern slope of a large rise of terrain of the Kraków-Częstochowa Upland (Polish: Jura Krakowsko-Częstochowska) that shelves toward the River Biała Przemsza valley. Regrettably, the exact coordinates of the find location are not known, and only very imprecisely defined forest limits where the discovery was made were indicated. The artefact in question is a reasonably well-preserved macehead of the so-called star-shaped type. The macehead was cast in a pre-prepared mould using a non-ferrous metal alloy with a dominant share of Cu, Pb, and Sb. A comparative analysis of maceheads with finds from the territory of Hungary and south-eastern Europe, as well as a concentration of such finds along the southern and the eastern borders of Poland allow for a supposition that such artefacts could also come from this direction. On the other hand, it cannot be excluded that the find is of local manufacture. Concerning its chronology, on the basis of analogies a wide time frame between the 12th and the first half of the 14th century can be proposed. The territory of the Kraków-Częstochowa Upland is a landscape that since the early 14th century has been marked by numerous works of military architecture. These were the background of the defensive system of the border of the Kingdom of Poland. Therefore, a high number of warriors could be at least temporarily stationed in this area. This can perhaps offer grounds to rather accept a later (that is, the 14th century) chronology of the artefact. Such a date can also be implied by its chemical composition.

Assessing the upper elevational limits of vegetation growth in global high-mountains

The upper elevational limits of vegetation growth in global high-mountains have been the focus for monitoring and assessment of climate change impacts on terrestrial ecosystems. However, existing studies have relied on field surveys that do not allow for large-scale analysis. Although remote sensing data have been used for local and regional monitoring of the vegetation upper boundaries, a global synthesis of the treeline and vegetation line (the upper altitudinal threshold for the existence of trees and the transition line from vegetation to bare land or permanent snow cover, respectively) in high-mountain ecosystems is still missing. To fill this gap, we developed two independent methods based on (1) the relationship between a Sentinel-2 vegetation index and elevation and (2) the European Space Agency's 10 m resolution land cover dataset (WorldCover), respectively, to automatically identify the upper elevational limits of treeline and vegetation line for each one-quarter degree grid across the global high-mountain areas. We obtained highly consistent results from the two methods, both of which are spatially consistent with ground surveyed treeline elevations. Our results are in line with the current understanding of the global distributions of tree and vegetation lines, which are observed at the highest elevations in the Tibetan plateau and decreasing for increasing latitudes. We find that the tree and vegetation lines are aspect-dependent, reaching higher elevations on the equatorial-facing slopes than on the polar-facing slopes in high latitudes, and the opposite in the middle latitudes. Our analysis shows that mountain height is the dominant factor in determining the upper elevational limits of tree and vegetation lines across the globe, while climatic conditions and soil properties also play important roles at regional scales. Our study provides a framework for monitoring the tree and vegetation lines in global high-mountains and provides an important benchmark for further examining their long-term changes in response to climate change.

The landscape impact of agricultural sheds in rural UNESCO site: Public preferences and mitigation solutions

The mitigation process of agricultural sheds into the landscape is crucial for aesthetic quality of its landscape and architectural integrity. The evaluation of how residents perceive these elements and identifying preferred solutions is crucial for landscape planning. For identifying sets of preferred mitigation solutions and defining shared criteria for landscape planning a representative sample of the population was investigated. We have estimated the willingness to pay for integrating contemporary agricultural sheds in a UNESCO landscape. Data were collected in six Core Zones of “Vineyard Landscape of Piedmont: Langhe-Roero and Monferrato” (North-West Italy). Preferences toward different mitigation measures of the agricultural sheds were investigated using a Discrete Choice Experiment (DCE) method. The DCE survey was carried out through face-to-face interviews involving 400 residents. The set of mitigation attributes (colour of the walls, colour of the roof, green barriers and plant green walls) was selected by means of a landscape analysis and presented to respondents using a set of images (close and distant views). Our study shows that the presence of green barriers (formal hedge and tree line) and the colour of the wall (green) are considered positive mitigation solutions. These attributes have a positive effect both in the close and the distant view. Our results confirmed that the distance may affect the visual impact of these buildings. Most of the respondents agree with the need to implement mitigation solutions for agricultural sheds, guaranteeing a better aesthetic enjoyment.

Soil microbial resource limitation along a subarctic ecotone from birch forest to tundra heath

Soil microorganisms regulate the decomposition of organic matter. However, microbial activities can also be rate-limited by the resource in lowest supply. Arctic ecosystems are being exposed to pronounced climate warming, with arctic greening, treeline advance and shrubification resulting in increased plant-derived carbon (C) inputs to soils, and faster rates of decomposition releasing mineral nutrients, potentially shifting the limiting factor for microbial growth. Here we used a “space-for-time” approach across a subarctic ecotone (birch forest, tree line, shrub and tundra sites). N and P fertilization treatments were also applied in the field, to test whether changes in resource limitation could be induced through nutrient loading of soils. In these soils, we measured the responses of bacterial and fungal growth as well as soil respiration to full factorial additions of C, nitrogen (N) and phosphorus (P) (“limiting factor assays”: LFA) to infer how the limiting factor for microbial growth would be affected by future climate change. We found that bacteria were triple-limited by C, N and P, while fungi were co-limited by C and N, with no shift in the limiting factor for bacterial or fungal growth across the ecotone. However, bacterial responses to the LFA were stronger in the tundra, showing 9-fold stronger increases in response to LFA-CNP addition compared to that in the forest. In contrast, fungal responses to the LFA were stronger in the forest, showing a 120% higher growth in response to LFA-CN addition, with no detectable response to LFA-CN addition in the tundra. These contrasting results suggested competitive interactions for resources between the two decomposer groups. Fertilization in the field shifted the bacterial resource limitation, but had no effect on the limiting factor for fungal growth. Together, our findings suggest that resource limitations for soil microorganisms will not change due to future warming, but rather affect degrees of fungal-to-bacterial dominance.

Impacts of Ecological Shading by Roadside Trees on Tea Foliar Nutritional and Bioactive Components, Community Diversity of Insects and Soil Microbes in Tea Plantation.

Roadside trees not only add aesthetic appeal to tea plantations, but also serve important ecological purposes for the shaded tea plants. In this study, we selected tea orchards with two access roads, from east to west (EW-road) and from south to north (SN-road), and the roadside trees formed three types of ecological shading of the adjoining tea plants; i.e., south shading (SS) by the roadside trees on the EW-road, and east shading and west shading (ES and WS) by the roadside trees on the SN-road. We studied the impacts of ecological shading by roadside trees on the tea plants, insects, and soil microbes in the tea plantation, by measuring the contents of soluble nutrients, bioactive compounds in the tea, and tea quality indices; and by investigating the population occurrence of key species of insects and calculating insect community indexes, while simultaneously assaying the soil microbiome. The results vividly demonstrated that the shading formed by roadside tree lines on the surrounding tea plantation (SS, ES, and WS) had adverse effects on the concentration of tea soluble sugars but enhanced the foliar contents of bioactive components and improved the overall tea quality, in contrast to the no-shading control tea plants. In addition, the roadside tree lines seemed to be beneficial for the tea plantation, as they reduced pest occurrence, and ES shading enhanced the microbial soil diversity in the rhizosphere of the tea plants.

Assessment of Past Decadal Dynamics of Tree Stands in Forest–Tundra Transition Zone on the Polar Ural Mountains Calibrated Using Historical and Modern Field Measurements

Altitudinal forest limits are typically climatically dependent, such that increasing temperatures connected to global warming are causing upslope shifts in treeline ecotones worldwide. However, at the local and regional levels, the degree of such a response is dependent on differences in climate, topography and soil features. In recent decades, attempts have been undertaken to estimate tree stand dynamics with remote sensing methods, but their resolution is still too coarse for a precise assessment of stand structural changes, and requires ground-truthing, which is not possible without historical data collected on a single-tree level. We used aerial photos (1962) and satellite images (2021) in combination with historical inventory data to investigate changes in open forest positions at different spatial scales at the eastern macroslope of the Polar Urals over the past 60 years. Additionally, obtained remote sensing data were validated on a single-slope level using tree crown size estimations. Our investigations showed that since 1960 up to present day, the total crown coverage increased from 6.9 to 22.1% within the test polygon. A highly spatially variable upslope advance in an open forest boundary was identified from 1.7 up to 7.1 m in altitude per decade. We revealed that the rate of tree stand transformations was to a great extent depended on the stand density in the 1960s, soil substrate type, moisture regime, slope aspect and inclination. Our results highlighted the necessity to consider the abovementioned factors when trying to predict climate-induced tree distributional responses in subarctic mountain regions.

Visual Analysis of Multisource Heterogeneous Data Based on Improved DPCA Algorithm

This paper proposes a multiview collaborative visual analysis system of network security based on a DPCA (clustering by fast search and find of density peaks) clustering algorithm called DPCANETVis, with network security analysis requirements for multisource heterogeneous data. Firstly, the system proposes an improved DPCA clustering algorithm based on the hierarchical relationship of mail sending and receiving to achieve the purpose of accurate classification. Secondly, a three-layer visual layout is designed to display relevant information such as data hierarchy, node relationship, behavior model, and other relevant information, by mixing a variety of interactive visual analysis methods such as tree diagram, word cloud, line diagram, subject river, and parallel coordinate. Lastly, based on the exploration of events, all suspicious nodes and their abnormal behaviors can be displayed in the system. Finally, the prototype system is used to analyze the network security log data set provided by the ChinaVis 2018, and the feasibility of the multilevel interactive visual analysis method for network security is verified through many experiments and discussions.

Effect of Industrial Airborne Pollution on the Chemical Composition of Pine Needle Litterfall at the Northern Distribution Limit of Pine Forests

Effect of Industrial Airborne Pollution on the Chemical Composition of Pine Needle Litterfall at the Northern Distribution Limit of Pine Forests

Response of rove-beetle (Staphylinidae) assemblages to the cumulative effect of wildfire and linear footprint in boreal treed peatlands.

Cumulative effects of anthropogenic and natural disturbances have become increasingly relevant in the context of biodiversity conservation. Oil and gas (OG) exploration and extraction activities have created thousands of kilometers of linear footprints in boreal ecosystems of Alberta, Canada. Among these disturbances, seismic lines (narrow corridors cut through the forest) are one of the most common footprints and have become a significant landscape feature influencing the maintenance of forest interior habitats and biodiversity. Wildfire is a common stand-replacing natural disturbance in the boreal forest, and as such, it is hypothesized that its effects can mitigate the linear footprint associated with OG exploration, but only a few studies have examined its effectiveness. We studied the short-term (1year post-fire) response of rove-beetle assemblages to the combined effects of wildfire and linear footprint in forest, edge, and seismic line habitats at burned and unburned peatlands along the southwest perimeter of the 2016 Horse River wildfire (Fort McMurray). While rove-beetle species richness was higher in seismic lines in both the burned and unburned habitats compared with the adjacent peatland, diversity was greater only in seismic lines of burned areas. Abundance was lower in the burned adjacent peatland but similarly higher in the remaining habitats. Assemblage composition on seismic lines was significantly different from that in the adjacent forest and edge habitats within both burned and unburned sites. Moreover, species composition in burned seismic lines was different from either unburned lines or burned forest and edge. Euaesthethus laeviusculus and Gabrius picipennis were indicator species of burned line habitats, are sensitive to post-fire landscapes and can occupy wet habitats with moss cover more efficiently than when these habitats are surrounded by unburned forest. Although these results are based on short-term responses, they suggest that wildfire did not reduce the linear footprint, and instead, the cumulative effect of these two disturbances had a more complex influence on rove-beetle recovery at the landscape level than for other invertebrates. Therefore, continued monitoring of these sites can become useful to evaluate changes over time and to better understand longer-term biodiversity responses to the cumulative effects of wildfire and linear disturbances in boreal treed peatlands, given the long-lasting effect of such disturbances.

Pollution-Induced Changes in the Composition of Atmospheric Deposition and Soil Waters in Coniferous Forests at the Northern Tree Line

This study examines the dynamics of the composition of atmospheric precipitation and soil water in coniferous forests under the influence of atmospheric emissions from the Severonickel Copper–Nickel Smelter in Russia’s Murmansk region. We studied dwarf shrub-green moss spruce forests and lichen-shrub pine forests, the most common in the boreal zone. Our results showed a significant intra- (below and between the crowns) and inter-biogeocenotic (spruce and pine forests) variation in the composition of atmospheric precipitation and soil water in forests exposed to air pollution. The concentrations of main pollutants in atmospheric fallout and soil water are tens (sulfates) and hundreds (heavy metals) times higher than in the background areas and typically higher below the crowns. The long-term dynamics (between 1999 and 2020) of the composition of atmospheric fallout and soil water in coniferous forests in the background areas and defoliating forests demonstrates a significant increase in nickel concentrations in recent years. This may be due to an increase in nickel concentrations in aerosols propagating over considerable distances. In pollution-induced sparse forests, a trend was found toward a decrease in the concentration of pollutants, which may indicate a decrease in the fallout of pollutants in the composition of larger particles close to the smelter.