Soil development and spatial differentiation in a glacial river valley under cold and extremely arid climate of East Pamir Mountains.

Melting glaciers release new ground surfaces, which may be either a source of greenhouse gas emissions or a sink for carbon dioxide. Studies carried out in subpolar and alpine ecosystems confirm the relatively rapid soil development and increase of carbon and nitrogen pools. However, observations from high-mountain glacier forelands in cold and dry climate are very scarce. This study analyses the impact of major environmental factors related to climate, topography, and vegetation, over a time-scale, on soil development and spatial soil differentiation in the foreland of Uisu Glacier, East Pamir Mountains. Moreover, the usefulness of the World Reference Base (WRB) and Soil Taxonomy in the classification of poorly developed soils in the ultracontinental climate was assessed. Geomorphological, pedological, and botanical surveys covered a sequence of terraces, alluvial fans, and end-moraines. Typical characteristics of the soils in the glacier foreland were: very high stoniness, coarse texture, high content of calcium carbonate, alkaline reaction, and low salinity. Soil development has extremely low intensity and was manifested in (a) soil organic carbon pools being among the lowest reported in the world (up to 1.4 kg m-2 in the layer 0-50 cm), and (b) the presence of cambic/calcic horizons only on landforms older than of Mid-Holocene age (estimated). It was concluded that both the extremely cold and extremely dry climate conditions in the Uisu Glacier foreland limit the water flux and availability, suppress vegetation density and variability, and slow down the rate of soil development. Both WRB and Soil Taxonomy were able to reflect the advances in soil development and spatial soil differentiation (Calcaric Hyperskeletic Leptosols - Calcaric Cambisols - Cambic Calcisols, and Gelifluvents - Haplocambids - Haplocalcids, respectively); however, highlighting different features developed under an extremely cold and dry climate conditions of the East Pamir Mountains.

Smouldering fire in a nutrient-limited wetland ecosystem: Long-lasting changes in water and soil chemistry facilitate shrub expansion into a drained burned fen.

Wildfires are natural phenomena which regulate functioning and stability of fire-adapted ecosystems. However, their occurrence may impair the functioning of fire-susceptible ecosystems by disturbing nutrient cycling and biodiversity. This work aimed to identify environmental factors shaping post-fire patterns of shrub expansion in a drained, burned peatland. This research was conducted in a fire-susceptible drained rich fen, located in Biebrza National Park (Poland), which was subjected to a large-scale smouldering fire in 2002. In 2014, water and soil chemistry were studied alongside with foliar nitrogen (N), phosphorus (P) and potassium (K) contents of a native shrub (Salix cinerea) in four vegetation types present after the fire. Unburned areas were dominated by herbaceous plants. Willows present were sparse and low, with chloroses and necroses. Their foliar nutrient content indicated strong K limitation. Moderately burned areas were dominated either by willows or nitrophilous plants. Willows in moderately burned areas had high chlorophyll content in leaves and their foliar nutrient content indicated a lack of evident nutrient limitation. In the moderately burned areas, relatively high contents of phosphates (P-PO43-) were recorded in soil and water. In areas with high fire severity, willows were withdrawing and their foliar nutrient content indicated N limitation. Decreased content of P-PO43- and ammonium (N-NH4+) in soil and water was also observed there. Thus, fire-induced changes in fen geochemistry were recorded twelve years after a disturbance which shaped the long-term dynamics of shrub expansion. The fire ceased K limitation in burned areas and increased P availability. Strong K limitation, which is typical in degraded fens, appeared to be critical for keeping unmanaged fen meadows with low shrub cover. The occurrence of strong K limitation in drained fen ecosystems may reduce the need for investment in conservation practices used to restrict shrub expansion (e.g. regular mowing or shrub removal).

Plant response to N availability in permafrost-affected alpine wetlands in arid and semi-arid climate zones.

Nutrient cycling in alpine permafrost-affected wetlands remains insufficiently studied, as it is influenced by a complex network of interrelated climatic and environmental factors, at both regional and local scale. Therefore, we applied mathematical models to examine relationship between environmental factors and plant functional traits reflecting N availability in wetland communities developed under locally variable conditions in a geographic and climatic gradient of high-altitude habitats. Moreover, we assessed impact of local differences in soil chemistry on plant fractionation of N isotopes as a response to N availability. Based on environmental data and chemistry of biomass from 192 study sites from the Pamir Mountains (Tajikistan) and Khangai and Khentei Mountains (Mongolia), a matrix of rank correlations was prepared for regional and local factors and community level plant functional traits. For the traits that were highly correlated either with regional or with local drivers (that is plant N:P ratio and plant δ15N), linear models were built, with a limited set of predictors selected according to the Risk Inflation Criterion and the SOS algorithm. The models were fitted for each of the studied regions. Presented regional models indicated significant influence of soil NH4+ and/or PO43- content on plant N:P ratio, which showed increase with altitude and lowering precipitation. Thus, its values clearly distinguished between the Pamir Mountains (high N:P) and the Mongolian ranges (low N:P). Models for plant δ15N showed its strong positive correlations with soil δ15N and soil salinity. Average values of plant δ15N were comparable for both study areas. The studied plant functional traits showed different response to regional and local drivers. Plant N:P ratio was controlled by regional drivers via their influence on soil NH4+ content. Contrastingly, plant δ15N was significantly affected by local factors, namely soil δ15N and soil salinity expressed as Na:EC.

Potential eolian dust contribution to accumulation of selected heavy metals and rare earth elements in the aboveground biomass of Tamarix spp. from saline soils in Kazakhstan.

In arid and semi-arid zones, atmospheric dust of different origins influences soil chemistry and plant biomass composition. Thus, studies on plant accumulation of heavy metals and rare earth elements (RREs) should include some assessments of potential eolian deposition. Here, we proposed the use of fractionation of metals in soils as an indirect method to assess potential atmospheric dust input to metal content in plant biomass. Our research was performed on individuals of Tamarix spp. growing on saline automorphic and hydromorphic soils in Kazakhstan. Studied soils could be, in general, classified as polluted, especially in industrial areas of Karaganda and Chromtau. However, concentrations of heavy metals and RREs in biomass remained low, as most of the studied elements were present in plant-inaccessible forms. Nevertheless, we recorded a high accumulation of Cd in biomass (70% of this element present in soils as plant-inaccessible fractions), which indicates the impact of Cd atmospheric deposition.

Nature's patchwork: How water sources and soil salinity determine the distribution and structure of halophytic plant communities in arid environments of the Eastern Pamir.

The eastern part of the Pamir Mountains, located in Central Asia, is characterized by great climatic continentality and aridity. Wetlands developed in this hostile region are restricted to spring areas, terraces of shallow lakes or floodplains along rivers, and provide diversified ecosystem services e.g. as water reservoirs, refugia for rare species and pastures for domestic cattle. These ecosystems are particularly susceptible to climate changes, that in the Pamir Mountains result in increased temperatures, intense permafrost/glacial melt and alterations of precipitation patterns. Climatic changes affect pasture management in the mountains, causing overutilization of sites located at lower elevations. Thus, both climate and man-induced disturbances may violate the existing ecological equilibrium in high-mountain wetlands of the Eastern Pamir, posing a serious risk to their biodiversity and to food security of the local population. In this context, we sought to assess how environmental drivers (with special focus on soil features and potential water sources) shape the distribution and diversity of halophytic plant communities developed in valleys in the Eastern Pamir. This task was completed by means of a vegetation survey and comprehensive analyses of habitat conditions. The lake terraces and floodplains studied were covered by a repetitive mosaic of plant communities determined by differences in soil moisture and salinity. On lower, wetter sites, this patchwork was formed by Blysmus rufus dominated salt marshes, saline small sedge meadows and saline meadows with Kobresia royleana and Primula pamirica; and on drier, elevated sites, by endemic grasslands with Hordeum brevisubulatum and Puccinellia species and patches of xerohalophytic vegetation. Continuous instability of water sources and summer droughts occurring in the Pamir Mountains may lead to significant structural and functional transformations of described wetland ecosystems. Species more tolerant to decreased soil moisture and/or increased soil salinity will expand, leading to alterations of ecosystem services provided by the Pamirs' wetlands. The described research will help to assess the current state of the wetlands and to predict directions of their future changes.

Interspecific differences in foliar 1 PAHs load between Scots pine, birch, and wild rosemary from three polish peat bogs.

Pine needles are one of the most commonly used bioindicators of polycyclic aromatic hydrocarbons (PAHs) in the environment. Therefore, the main objective of the current research was the assessment of PAHs accumulation potential of Scots pine (Pinus sylvestris L.) needles in comparison to wild rosemary (Rhododendron tomentosum Harmaja) and birch (Betula spp.) leaves. Our study was carried out on three peat bogs subjected to different degree of anthropopression, which gave us also the opportunity to identify local emission sources. Pine needles had the lowest accumulation potential from all the studied species. The highest accumulation potential, and hence carcinogenic potential, was observed for wild rosemary leaves. As far as emission sources are concerned, the most pronounced influence on atmospheric PAHs loads had traditional charcoal production, resulting in great influx of heavy PAHs. Observed seasonal changes in PAHs concentrations followed the pattern of winter increase, caused mainly by heating season, and summer decrease, caused mainly by volatilization of light PAHs.

The diversity of endophytic fungi in the above-ground tissue of two Lycopodium species in Poland.

Endophytes are a large and diverse group of fungi that colonize healthy plant tissues without causing any symptoms. The majority of studies have focused on angiosperm and conifer hosts and few have examined the endophytes of lycophytes. In the present study, we characterized culturable endophytic fungi in two closely related Lycopodium species (L. annotinum and L. clavatum) from pine, beech, oak and spruce forests across Poland. More than 400 strains were isolated but only 18 Ascomycete species were identified. Members of the Dothideomycetes dominated the fungal endophyte communities in Lycopodium. The most abundant taxa cultured were Phoma brasiliensis (from L. clavatum) and Paraconiothyrium lycopodinum (from L. annotinum). Five taxa were isolated exclusively from L. annotinum, but only two of them (Paraconiothyrium lycopodinum and Mycosphaerella sp.) were relatively abundant. Two taxa were only found in L. clavatum, namely: Stagonospora pseudovitensis and an unidentified Dothideomycete. The taxon assigned as Ascomycota 2 (SH219457.06FU) was isolated only from strobili of both host species. Direct PCR and cloning from L. annotinum shoots revealed a substantially greater endophyte richness compared with the results from culturing.