Subalpine Grasslands Research Articles

Encroachment of shrubs into subalpine grasslands in the Pyrenees modifies the structure of soil fungal communities and soil properties.

The encroachment of shrubs into grasslands is common in terrestrial ecosystems dominated by grass. Land abandonment and favourable climatic trends in recent decades have favoured the expansion of shrubs into subalpine grasslands in many mountainous regions across Europe. The advance of the succession from grassland to shrubland is expected to have a major impact on ecosystem functioning. We used DNA metabarcoding to assess whether the structure of soil fungal communities varied along the succession from subalpine grassland to shrubland in the Pyrenees, and investigated whether shrub encroachment was associated with changes in soil properties. The expansion of shrubs increased the soil C:N ratio and/or reduced the N, P or K contents. Plant-driven changes in soil properties were strongly associated with the compositional turnover of fungi, including arbuscular mycorrhizal, ectomycorrhizal, ericoid, root endophytic, saprotrophic, lichenised and pathogenic fungi. Total richness and the richness of most functional groups were correlated with soil P, N and the C:N or N:P ratios. We show that the interplay between abiotic factors (changes in soil properties) and biotic factors (occurrence and identity of shrubs) played a key role in the structure and uniqueness of soil fungal communities along the succession.

Horse Activity is Associated with Degraded Subalpine Grassland Structure and Reduced Habitat for a Threatened Rodent

Feral (wild) horses present significant challenges for landscape managers. A major effect of horses is trampling, which erodes soil and alters vegetation cover, which is often critical habitat for threatened animals. We examined the direct and indirect impacts of horses, kangaroos, and rabbits on the broad-toothed rat (Mastacomys fuscus), a threatened rodent in subalpine grasslands in Kosciusko National Park, which contains a large wild horse population. Our objective was to examine the relationship between the activity of different herbivores and 1) structural attributes of the vegetation (cover and density of different plant groups) and 2) length of broad-toothed rat runways and the presence of scat along these runways as proxies of broad-toothed rat activity. We assessed herbivore activity and measured vegetation cover, structure, and richness and total length of runways used by broad-toothed rats as a measure of activity. We used structural equation modeling to test the hypothesis that horse activity would lead to reductions in rat habitat directly, by increasing disturbance, and indirectly, by altering vegetation structure. Quadrats showing no evidence of horse activity had longer broad-toothed rat runways, taller but fewer grasses, double the shrub cover, and lower plant richness than quadrats showing evidence of horse activity. Structural equation modeling showed that there were no significant direct associations between horse activity and rat activity. However, increasing horse activity was associated with an indirect negative effect on broad-toothed rat activity by suppressing the positive relationship between grass height and rat activity. There were no significant effects of rabbits on any environmental variables, and kangaroo grazing was associated with an increase in shrub cover only. Disturbance by horses likely alters vegetation structure, by reducing grass height, making it less suitable for broad-toothed rats, thereby reducing their populations. Horses should be restricted from accessing critical broad-toothed rat habitat.

Pits, mounds, and vernal ponds in a Tasmanian subalpine grassland

AbstractFalling trees commonly turbate soils in primary forest, creating characteristic edaphic patterns related to pit and mound topography. Vernal ponds with associated mounds were observed in mineral soils on a treeless plain in subalpine Tasmania, Australia. The hypothesis that paired ponds and mounds on the plain originated as pit and mound features in forests that were later destroyed by fire was tested by comparing the soils and landforms caused by recent tree falls in adjacent forest with those on the plain. The soil characteristics, orientations, and dimensions of the ponds and mounds were consistent with a tree fall origin, although rare secondary ponds on the tops of mounds may derive from the burrowing activities of the medium‐sized marsupial, Vombatus ursinus (common wombat). The characteristics of pond and mound soils suggested that most were hundreds to thousands of years old, with the ponds persisting because of differences in deflation, deposition, and organic matter formation between themselves and adjacent persistently dry land.

Recovery of subalpine grasslands 15 years after landscape level fires

As conditions warm, previously rare landscape level fires are more likely to affect vegetation in the Australian Alps including in subalpine grasslands. The recovery of this community was assessed using paired unburnt and burnt plots (30 × 20 m) at 10 sites 15 years after largescale fires that burnt >70% of the subalpine zone in Kosciuszko National Park. There were few significant differences found: higher cover of shrubs (17.8% burnt vs 11.3% unburnt plots), and taller vegetation (22.6 vs 19 cm). However, vegetation cover (97%), species richness (38 taxa), composition and limited presence of invasive plants (10 species, 8.5% cover) were not significantly different. This differs from results six weeks and one year post-fire, when there were clear differences in the cover and composition of vegetation. These results indicate that subalpine grasslands recover from single fires, but with warmer and drier conditions becoming more common, and repeat fires in some areas, the distribution, structure and composition of this and other communities in the Australian Alps will change.

The dynamics of rush circles in subalpine grassland

Geometric patterning in vegetation is often the result of cyclic succession, although circular forms sometimes result from the clonal growth of individual plants. We investigated whether cyclic succession or clonal growth created patterns in Poa subalpine grassland with rush (Empodisma minus) circles on the Central Plateau of Tasmania, Australia. We mapped change in the number, size and reflectance of the rush circles from 1953 to 2011 using aerial photographs, tested whether the circles occurred in distinct microenvironments, and whether the circles were likely to be individuals and determined whether the smallest circles were associated with disturbance. The number and area of circles increased with time. As circles became larger they became more reflective, evenly across their extent. The circles were associated with flatter patches in the plain. Surface soil characteristics did not differ between an exemplar circle and adjacent grassland. The Empodisma foliage in each circle tended to have colour consistently distinct from that of other circles in its vicinity, indicating that the circular form was a product of vegetative expansion of a single individual at a much more rapid velocity than the expansion of woody plant rings. The smaller circles were sometimes associated with frost-damaged Astelia alpina mounds, although far from confined to them. We did not find any instances of Empodisma circles <0.1 m in diameter. We deduced that the probability of establishment of new individuals of Empodisma in the grassland was extremely low, or depended on an infrequent disturbance. Although the increasing reflectance of circles with size and the lack of differentiation of soils between circle and grassland indicated the possibility of cyclic succession, the area covered by circles increased at the decadal time scale. The increases in circle coverage and number may have resulted from changes in climate and grazing regimes on the eastern Central Plateau since the 1940s.

Effects of snow pack reduction and drought on litter decomposition in subalpine grassland communities

In subalpine grasslands, litter decomposition controls soil nutrient availability and is highly sensitive to increasing intensity and frequency of extreme climate events, potentially impacting grasslands diversity and functioning. Here, we assessed the effects of early snowmelt and summer drought on decomposition, and how these were modulated by agricultural management. In a common garden, conservative and exploitative assembled communities were submitted for two years to combined snow removal and drought, and to cutting and fertilization. We measured decomposition rates of standard and native leaf material from each plant communities on their respective soils. We observed relatively weak climatic stress effects on decomposition rates. Management increased decomposition rates and remaining litter N contents through leaf quality improvement rather than changed soil biotic activity. Climate events impacted the decomposer community and limited litter N immobilization in conservative communities. Less recalcitrant litter of exploitative species facilitated decomposition and counterbalanced the negative effects of climate stress. Our results suggest that drought and earlier snowmelt could decrease N availability in subalpine grasslands due to reduced litter biomass and decomposition. In the long-term climate change may shift subalpine grasslands towards more conservative plant composition and lower soil fertility.

Decomposition processes interacting with microtopography maintain ecosystem heterogeneity in a subalpine grassland

Grasslands are among the largest ecosystems in the world and store up to 30% of the global reserves of carbon. Decomposition processes have a crucial role in maintaining carbon balance, but few studies have investigated the heterogeneity of this process at small scale, especially in alpine ecosystems. We aimed at investigating the interactions between decomposition and environmental heterogeneity at microscale (i.e. elevation gradient <1 m) in a subalpine grassland on the western Italian Alps characterised by the presence of parallel hummock and hollow areas. In the study area we monitored microenvironmental drivers (soil temperature and soil water content), plant distribution and decomposition. The latter was studied through a litter bags approach followed by elemental analysis, 13C NMR and FT-IR spectroscopies. Microtopography exerted a direct and indirect control over litter decomposition by affecting plant species distribution and microclimatic conditions. The different elemental and biochemical properties of plants, interacting with microtopography, led to a higher decomposition rate of forb than grass litter, and in hollow than in hummock areas. The observed differences were both quanti- and qualitative. Decomposition processes bridge the gap between plant community structure and ecosystem functioning, determining a feedback mechanism that maintains ecosystem heterogeneity at the microscale.

Subalpine vegetation in Giresun Mountains (Turkey)

AbstractIn this study, the subalpine vegetation in the Giresun Mountains of northern Turkey was investigated. The study area included north- and south-facing slopes at altitudes ranging betweenc.2000 and 2500 meters. For vegetation classification and for describing the relationships between vegetation and environment, traditional Braun-Blanquet methods and multivariate analysis techniques were used. The vegetation mainly consisted of subalpine grasslands and coniferous cushion scrubs.Caricetea curvulaeandAstragalo microcephali-Brometea tomentelliwere found to be dominant syntaxa in the vegetation of the study area. Land topography, soil physical and chemical factors and species richness have important impacts on the development of subalpine vegetation according to the results of multivariate analysis. Three associations and two subassociations were newly determined and classified. Hemicryptophytes, chamaephytes and geophytes participated in the floristic composition of these syntaxa. EUNIS habitat code and names for described syntaxa were also proposed.

Taxonomic and functional facets of the resilience to management of mown subalpine grasslands

AbstractQuestionsSustaining ecosystem services for society in the face of global change is a major challenge. Resilience, an ecosystem's ability to absorb disturbance and return to its initial functioning, is critical for this. We assessed the resilience of mown subalpine grasslands following restoration management. Using a novel multi‐indicator approach, we asked how different taxonomic and functional facets of biodiversity influence resilience mechanisms. We demonstrated this approach for a case study in subalpine grasslands, asking: how resilient are grasslands dominated by Patzkea paniculata and their agronomic services to changing mowing regimes?LocationVillar d'Arène, Hautes‐Alpes, Provence‐Alpes‐Côte d'Azur, France. Boundary area of Ecrins National Park.MethodsA manipulative experiment tested the reciprocal effects of mowing cessation and mowing resumption for 10 years. We analysed floristic composition data following four steps. First, we used the Community Structure Integrity Index (CSII; Jaunatre et al., ) to obtain qualitative and quantitative summaries of taxonomic responses. The second step focused on taxonomic biodiversity using species richness, Simpson and Pielou indices, and responsive species identified in the first step. Third, we analysed functional diversity responses using functional groups and community weighted mean (CWM) of vegetative plant traits. Finally, we quantified ecosystem services impacts by estimating fodder quantity and quality using trait‐based models.ResultsThe mowing manipulation demonstrated the high resilience of P. paniculata grasslands and revealed reversibility of transitions between mown and unmown states. By reducing the abundance of P. paniculata, the resumption of mowing restored forage quality. Supported by a complementary case study on post‐disturbance re‐sowing in hay meadows, this study demonstrates the resilience of mown subalpine grasslands to management change and explores underlying belowground mechanisms of vegetative regeneration and belowground reserves.ConclusionOur novel multi‐indicator approach provides multifaceted mechanistic understanding necessary to anticipate impacts of socio‐ecological changes and to maintain the multiple benefits of mountain grasslands. Addressing the different facets of biodiversity from abundance data that are systematically collected in impact or monitoring assessment, this approach provides a common framework, widely applicable to different types of restoration or management interventions, across regions and biota.

Seasonality alters drivers of soil enzyme activity in subalpine grassland soil undergoing climate change

In mountain ecosystems with marked seasonality, climate change can affect various processes in soils, potentially modifying long-term key soil services via change in soil organic carbon (C) storage. Based on a four-year soil transplantation experiment in Swiss subalpine grasslands, we investigated how imposed climate warming and reduced precipitation modified the drivers of soil carbon enzyme potential activities across winter and summer seasons. Specifically, we used structural equation models (SEMs) to identify biotic (microbial community structure, abundance and activity) and abiotic (quantity and quality of organic matter resources) drivers of soil C-enzymes (hydrolase and oxidase) in two seasons under two different climate scenarios. We found contrasting impacts of the climate manipulation on the drivers of C-enzymes between winter and summer. In winter, no direct effect of climate manipulation (reduced rainfall and warming) on enzyme activity was observed. Yet, climate indirectly down-regulated enzyme activity through a decrease in the availability of water extractable organic carbon (WEOC) labile resources. During summer, reduced soil moisture –induced by the climate manipulation– directly reduced soil microbial biomass, which led to a decrease in C-enzyme activity. In general, across both seasons, neither microbial community structure, nor organic matter quality were strong determinants of enzymatic activity. In particular organic matter recalcitrance (aromaticity) was not found as a general driver of either hydrolase or oxidase C-enzyme potential activities, though we did observe higher C-enzyme activities led to an increase of particulate organic matter recalcitrance in the summer season. Overall, our results highlight the seasonality of climate change effects on soil organic matter enzymatic decomposition, providing a comprehensive picture of seasonal potential cause and effect relationships governing C mineralization in subalpine grasslands.

El Pirineo Aragonés como paisaje cultural

Los paisajes culturales se han construido a lo largo de siglos o milenios como consecuencia de la adaptación de diferentes culturas a la heterogeneidad de los sistemas naturales. Son el resultado de una serie de iniciativas, generalmente colectivas, que dan lugar a la superposición de diferentes elementos que corresponden a distintos momentos históricos. En ambientes de montaña los factores más influyentes en la construcción de paisajes culturales son el escalonamiento altitudinal de los pisos geoecológicos, la diversidad topográfica y topoclimática, el crecimiento demográfico, los acontecimientos históricos (incluyendo la superposición de culturas) y la influencia de los mercados. El éxito de las sociedades montanas dependió de su conocimiento del medio y, especialmente, de la importancia de la gravedad en un ambiente de alta energía, con el fin de controlar la escorrentía y la erosión del suelo. Por eso, las áreas de montaña necesitan una organización social y territorial compleja, para hacer frente a la adversidad provocada por la rudeza del clima y la explotación de laderas pendientes. Naturalmente, este esfuerzo implica un gran gasto de energía en la conservación del paisaje, que puede desmoronarse de manera irreversible por muchas razones, entre ellas la despoblación y el abandono de tierras de cultivo, que conducen a lo que podemos llamar una deconstrucción del paisaje. Esta última representa la pérdida de un patrimonio cultural que, estudiado a fondo, nos enseña mucho acerca de la forma óptima de aprovechar los recursos naturales y también de los errores que se han cometido en el pasado. A pesar de los cambios recientes, quedan aún muchos restos de los paisajes culturales pirenaicos: campos cercados que representan una creciente individualización en la gestión del territorio, laderas aterrazadas, panares en el límite superior del piso montano, y los extensos pastos subalpinos, que representan la eliminación de un espacio forestal para favorecer los movimientos trashumantes.

13C isotopic signature and C concentration of soil density fractions illustrate reduced C allocation to subalpine grassland soil under high atmospheric N deposition

We followed soil C fluxes in a subalpine grassland system exposed to experimentally increased atmospheric N deposition for 7 years. Earlier we found that, different from the plant productivity response, the bulk soil C stock increase was highest at the medium, not the high N input as hypothesized. This implies that a smaller N-deposition rate has a greater potential to favor the biological greenhouse gas-sink. To help elucidate the mechanisms controlling those changes in SOC in response to N deposition, we produced four soil density fractions and analyzed soil organic C concentration [SOC], as well as δ13C signatures (δ13CSOC) of SOC components. Soil respired CO2 (δ13CCO2) was analyzed to better distinguish seasonal short term dynamics from N-deposition effects and to identify the predominant substrate of soil respiration.Both at the start of the experiment and after 7 years we found a strong, negative correlation between [SOC] and δ13CSOC of the soil density fractions in the control treatment, consistent with an advanced stage of microbial processing of SOC in fractions of higher density. During the experiment the [SOC] increased in the two lighter density fractions, but decreased in the two heavier fractions, suggesting a possible priming effect that accelerated decomposition of formerly recalcitrant (heavy) organic matter pools. The seasonal pattern of soil δ13CCO2 was affected by weather and canopy development, and δ13CCO2 values for the different N treatment levels indicated that soil respiration originated primarily from the lightest density fractions.Surprisingly, [SOC] increases were significantly higher under medium N deposition in the <1.8 fraction and in bulk soil, compared to the high N treatment. Analogously, the depletion of δ13CSOC was significantly higher in the medium compared to the high N treatment in the three lighter fractions. Thus, medium N deposition favored the highest C sequestration potential, compared to the low N control and the high N treatment.Clearly, our results show that it is inappropriate to use plant productivity N response as an indicator for shifts in SOC content in grassland ecosystems. Here, isotopic techniques illustrated why atmospheric N deposition of 14 kg N ha−1 yr−1 is below, and 54 kg N ha−1 yr−1 is above a threshold that tips the balance between new, assimilative gains and respiratory losses towards a net loss of [SOC] for certain soil fractions in the subalpine grassland.

Effects of prescribed burning for pasture reclamation on soil chemical properties in subalpine shrublands of the Central Pyrenees (NE-Spain)

The abandonment of the traditional pastoral activities in the subalpine grasslands of the Central Pyrenees (NE-Spain) has resulted in shrub encroachment processes that are dominated by species such as the Echinospartum horridum. Therefore, prescribed burning has been recently readopted in this region as a management tool to stop the spread of shrubs and recover grasslands. We aimed to assess the effect that this practice may have on soil chemical properties such as SOC, N, pH, EC, water-extractable and exchangeable cations (Ca2+, Mg2+ and K+), cation exchange capacity, inorganic N forms (N-NH4+ and N-NO3−) and available P. We studied two prescribed burnings conducted at the subalpine level of the Central Pyrenees in the municipalities of Tella-Sin (April 2015) and Buisán (November 2015). At each site, the topsoil was sampled in triplicate at soil depths of 0–1, 1–2 and 2–3 cm immediately before (U), immediately after (B0) and one year after (B12) burning, and litter and/or ashes were removed prior to sampling. The results indicate that in the B0 samples, burning significantly reduced the SOC and N contents as well as the exchangeable Ca2+ and Mg2+ at 0–1 cm, whereas the rest of the studied properties remained virtually unchanged. However, in the B12 samples we detected a decrease of nutrient content that was probably related to leaching and/or erosion processes.

Ammonia Emissions from Subalpine Forest and Mountain Grassland Soils in Rocky Mountain National Park.

Atmospheric deposition of NH and NH contributes to eutrophication within sensitive subalpine ecosystems of Rocky Mountain National Park (RMNP) in the United States. However, little is known about the local contribution of NH from soils within the park. Thus, the goal of this study was to quantify and compare NH emissions from intact soil cores sampled from a subalpine grassland and forest within RMNP. Cores were collected at 2-wk intervals from 20 June 2011 to 12 Sept. 2011 and transferred to a laboratory chamber system for NH flux measurements. Additionally, N wet deposition was monitored at the sampling location to investigate possible impacts on NH soil emissions. The average quantifiable NH emissions (with SDs) from intact soil cores analyzed in the laboratory (23°C) were 0.42 ± 0.30 mg NH-N m d for grassland soil and 0.21 ± 0.03 mg NH-N m d for forest soil ( < 0.001). A mechanistic model was developed to estimate the impact of temperature on soil emissions using the chamber data and field-site air temperatures. Average estimated NH emissions from the field site over the study period were 0.21 and 0.082 mg NH-N m d for grasslands and forests, respectively. Ammonium wet deposition was not correlated to short term reemission of NH based on N isotope analysis. This work provides new information on the magnitude of NH emissions from native subalpine soils, indicating that natural emissions are not likely major sources of NH in the RMNP airshed.

A prognostic phenology model for alpine meadows on the Qinghai–Tibetan Plateau

Phenology models are useful tools to study phenology shifts and their responses to climate change. Multiple factors including temperature, precipitation, photoperiod, insolation, and snow can affect the phenology of alpine grasslands on the Qinghai–Tibetan Plateau (QTP), but most models applied on the QTP have only considered the influences of temperature or temperature and precipitation. This study presents a multi-factor-driven phenology model, the Alpine Meadow Prognostic Phenology (AMPP) model, based on the Growing Season Index (GSI), to predict both leaf onset and offset dates of QTP alpine meadows at the community scale. Five factors including daily minimum air temperature, precipitation averaged over the previous month, photoperiod, global solar radiation, and snowfall were combined into an integrated index, the Alpine Meadow Growing Season Index, to quantify climatic limitations on foliar development of QTP alpine meadows. A case study was conducted using the observed leaf onset and offset dates of dominant species in QTP Kobresia meadows from 1989 to 2016. The root-mean-square errors (RMSEs) of modeled leaf onset and offset dates from the AMPP model were 6.9 d and 11.0 d, respectively, decreasing by 13.8%–48.9% and 7.6%–47.1% compared with the null model and seven other phenology models. The correlation coefficients between the predicted and observed leaf onset and offset dates were 0.75 and 0.34, respectively, higher than the 0.50–0.68 and −0.22–0.11 from other models. The RMSE ranges of predicted leaf onset and offset dates among three different sites were 2.9 d and 1.1 d, respectively, lower than or equal to the 3.6–12.4 d and the 1.1–6.9 d from other models. Results indicated that the AMPP model clearly improved the prediction accuracy and simulation of the interannual variability of leaf onset and offset dates and showed more robust simulations at different sites. Moreover, this model can be easily embedded into most ecosystem process models and applied to other alpine or subalpine grasslands once it has been adapted to their requirements.

Progressively excluding mammals of different body size affects community and trait structure of ground beetles

Mammalian grazing induces changes in vegetation properties in grasslands, which can affect a wide variety of other animals including many arthropods. However, the impacts may depend on the type and body size of these mammals. Furthermore, how mammals influence functional trait syndromes of arthropod communities is not well known.We progressively excluded large (e.g. red deer, chamois), medium (e.g. alpine marmot, mountain hare), and small (e.g. mice) mammals using size‐selective fences in two vegetation types (short‐ and tall‐grass vegetation) of subalpine grasslands. We then assessed how these exclusions affected the community composition and functional traits of ground beetles (Coleoptera, Carabidae), and which vegetation characteristic mediated the observed effects.Total carabid biomass, the activity densities of carabids with specific traits (i.e. small eyes, short wings), the richness of small‐eyed species and the richness of herbivorous species were significantly higher when certain mammals were excluded compared to when all mammals had access, regardless of vegetation type. Excluding large and medium mammals increased the activity density of herbivorous carabid species, but only in short‐grass vegetation. Similarly, excluding large mammals (ungulates) altered carabid species composition in the short‐, but not in the tall‐grass vegetation. All these responses were related to aboveground plant biomass, but not to plant Shannon diversity or vegetation structural heterogeneity.Our results indicate that changes in aboveground plant biomass are key drivers of mammalian grazers’ influence on carabids, suggesting that bottom–up forces are important in subalpine grassland systems. The exclusion of ungulates provoked the strongest carabid response. Our results, however, also highlight the ecological significance of smaller herbivorous mammals. Our study furthermore shows that mammalian grazing not only altered carabid community composition, but also caused community‐wide functional trait shifts, which could potentially have a wider impact on species interactions and ecosystem functioning.

Automating analysis of vegetation with computer vision: Cover estimates and classification.

This study develops an approach to automating the process of vegetation cover estimates using computer vision and pattern recognition algorithms. Visual cover estimation is a key tool for many ecological studies, yet quadrat‐based analyses are known to suffer from issues of consistency between people as well as across sites (spatially) and time (temporally). Previous efforts to estimate cover from photograps require considerable manual work. We demonstrate that an automated system can be used to estimate vegetation cover and the type of vegetation cover present using top–down photographs of 1 m by 1 m quadrats. Vegetation cover is estimated by modelling the distribution of color using a multivariate Gaussian. The type of vegetation cover is then classified, using illumination robust local binary pattern features, into two broad groups: graminoids (grasses) and forbs. This system is evaluated on two datasets from the globally distributed experiment, the Nutrient Network (NutNet). These NutNet sites were selected for analyses because repeat photographs were taken over time and these sites are representative of very different grassland ecosystems—a low stature subalpine grassland in an alpine region of Australia and a higher stature and more productive lowland grassland in the Pacific Northwest of the USA. We find that estimates of treatment effects on grass and forb cover did not differ between field and automated estimates for eight of nine experimental treatments. Conclusions about total vegetation cover did not correspond quite as strongly, particularly at the more productive site. A limitation with this automated system is that the total vegetation cover is given as a percentage of pixels considered to contain vegetation, but ecologists can distinguish species with overlapping coverage and thus can estimate total coverage to exceed 100%. Automated approaches such as this offer techniques for estimating vegetation cover that are repeatable, cheaper to use, and likely more reliable for quantifying changes in vegetation over the long‐term. These approaches would also enable ecologists to increase the spatial and temporal depth of their coverage estimates with methods that allow for vegetation sampling over large spatial scales quickly.

Woody encroachment and soil carbon stocks in subalpine areas in the Central Spanish Pyrenees

Woody encroachment has been an ongoing process in the subalpine belt of Mediterranean mountains, after land abandonment, the disappearance of the transhumant system and the decrease of the livestock number. The main objectives of this study were: (i) to identify land use/land cover (LULC) changes from 1956 to 2015, and (ii) to investigate the effects of LULC changes in physical and chemical soil properties and soil organic carbon (SOC) and nitrogen (N) stocks. It is hypothesized that woody encroachment in the subalpine belt may lead to significant changes in soil properties, and will generate an increase in the SOC stocks. A land use gradient was identified in the subalpine belt of the Central Spanish Pyrenees: (i) subalpine grasslands, (ii) shrublands, (iii) young forests, and (iv) old forests. Mineral soil samples were collected every 10 cm, down to 40 cm, at three points per each LULC and a total of 48 samples were analyzed. The results showed that (i) woody encroachment has occurred from 1956 to 2015 due to the expansion of coniferous forests and shrublands (at the expense of grasslands), (ii) land cover and soil depth had significant effects on soil properties (except for pH), being larger in the uppermost 0–10 cm depth, (iii) SOC and N contents and stocks were higher in the grassland sites, and (iv) the woody encroachment process initially produced a decrease in the SOC stocks (shrublands), but no differences were observed considering the complete soil profile between grasslands and young and old forests. Further studies, describing SOC stabilization and quantifying above-ground carbon (shrub and tree biomass) are required.

The ophiolitic communities of Shebenik-Jablanice National Park (Albania)

The Shebenik-Jablanice National Park is located in east central Albania which is characterized by one of the most important outcrops of the Mirdita ophiolitic formation. Ophiolites are often serpentinized and rich in metals, and present therefore a specialized flora and vegetation, which has attracted much research, but which is still incompletely known. In this paper we present the main communities of this vegetation, which encompasses subalpine grasslands, scrub and dry grasslands. Six associations are presented as new (Stachyo scardicae-Buxertum sempervirentis, Daphno oleoidi-Ericetum herbaceae, Carici sempervirentis-Seslerietum coerulantis, Carici macrolepidis-Genistetum hassertianae, Alysso bertolonii subsp. scutarinum-Euphorbietum glabriflorae, Sedo serpentini-Festucopsietum serpentini) and a few others are presented without a formal description (Bornmuellera baldaccii community, Astragalus angustifolius community, Viola magellensis scree vegetation). Serpentinicolous dry grassland vegetation of the Shebenik mountains is compared to other communities of serpentines in Italy, Balkans and Greece and a new alliance is described for this community, Festucopsion serpentini (Halacsyetalia sendtneri) vicariant of the Centaureo-Bromion fibrosi which occurs in northern Albania and Kosovo. The alliance is characterized by a set of species which do not occur or are rare further north and by a relatively dry climate with Mediterranean affinity. We also present a thorny cushion vegetation with Astragalus angustifolius, which grows on limestone but is vicariant to the analogous community with Genista hassertiana. Finally, considering the rarity of these communities at continental scale, and their richness of endemic and rare species, we present the description of a new habitat for future inclusion in the Annex I of the Habitat Directive.

Habitat conditions, stage structure and vegetation associations of geographically isolated subalpine populations of Salix lapponum L. (Salicaceae) in the Krkonoše Mts (Czech Republic)

Shrub communities are important components of the subalpine vegetation. We focused on habitat conditions and stage structure (flowering and non-reproducing individuals) of stands of the endangered Salix lapponum in the Krkonose Mts, Czech Republic. Habitat conditions were determined using soil sample analyses and Ellenberg indicator values (EIVs) derived from fine-scale (1 × 1 m) vegetation plots. The fine-scale plots were compared with coarse-scale releves with the occurrence of S. lapponum acquired from the Czech National Phytosociological Database. We found that S. lapponum grows on nutrient-poor, acidic soils with high relative water contents, high amounts of total nitrogen, low amounts of phosphorus, moderate amounts of magnesium and low to moderate amounts of calcium. The overall proportion of non-reproducing individuals was 35.2%, but strong variations were observed among populations (0–100%). Co-occurring species and EIVs data indicated that flowering individuals are relatively more common in humid, nutrient-rich and warmer microhabitats than non-reproducing ones. Well-developed (“typical”) stands of S. lapponum with a dominance of flowering individuals occur along alpine springs, streams and in glacial cirques (= association Salicetum lapponum Zlatnik 1928), but S. lapponum also grows along transitional mires and peat bogs and in subalpine grasslands. Coarse-scale releves were similar to “typical” stands of S. lapponum at the fine scale but were differentiated from them by high frequencies of several, mainly broad-leaved forbs and herbs typical of moist to wet and fertile soils. Threats to S. lapponum and the future prospects of its stands in the Krkonose Mts are briefly discussed.