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The alpine vegetation of Europe and the Caucasus has experienced substantial changes due to climate warming and reduced grazing. Exposed ridge communities, such as alpine heaths, are presumed to be less vulnerable to such processes. Herein, we analyze long-term dynamics (over 37 years) of an alpine lichen heath in the Teberda State Biosphere Reserve, Karachaevo-Cherkessian Republic, Russia. We counted the shoots of all vascular plants present on permanent plots. Autocorrelated linear regressions, a non-metric multidimensional scaling ordination, and a fourth-corner analysis were applied to characterize the relationships between shoot numbers, climate variables (temperatures and precipitation), functional traits, and species strategies. Nine species, including dominant Festuca ovina L. and Antennaria dioica (L.) Gaertn., increased their abundances, whereas Carex spp. were observed to decrease. The overall dynamics were mainly driven by increasing mean temperatures during the growing season (July and August). None of the changes observed in the selected traits were correlated with increasing or decreasing numbers of species; however, some traits (plant height, specific root length, specific leaf area, and leaf carbon content) were potentially associated with climate variables. The observed dynamics suggested an overall increase in the abundance of herbaceous plants. Generally, our results support “greening” effects in tundra and alpine biomes.

Widespread ecological succession occurs in abandoned temperate semi-natural meadows, but the process is still not fully understood. In the Central Forest Reserve, located in the Tver Oblast of nort...

The rate of plant litter decomposition depends on two simultaneous processes: the decomposition and stabilization of organic matter. To compare the rates of these processes in various ecosystems now a Tea Bag Index (TBI) is widely used. The samples of standard material (green tea and rooibos) were buried into soil at the depth of 8 cm in four herbaceous plant communities of Central Forest State Nature Biosphere Reserve (CFSNBR) and seven communities of the Moscow river floodplain near the MSU Zvenigorod biological station (ZBS). Considering the mass losses of samples during the incubation time we calculated the values of decomposition constant and stabilization factor according to the protocol by J. A. Keuskamp et al. (2013) and estimated the links of these parameters with Ellenberg’s ecological indicator values. The stabilization factor values ranged from 0.122 g/g in Filipendula community of CFSNBR to 0.379 g/g at the natural levee of the Moscow river, and the decomposition constant values ranged from 0.0089 g/g/day in Filipendula community of CFSNBR to 0.0308 g/g/day at the slope of the high floodplain. The mean values of these parameters were significantly positively correlated. The decomposition rate was lower in the communities of CFSNBR and was positively correlated with the soil pH Ellenberg’s indicator values. The stabilization factor values did not depend on the region and decreased with the increase in soil moisture and nitrogen. The mainland meadows of CFSNBR and the meadows of the high floodplain of the Moscow river, belonging to Cynosurion cristati alliance, had the most similar parameters of decomposition.

Diversity patterns of tropical alpine vegetation is poorly studied. We estimated vascular plant floristic richness for two typical afro-alpine communities in Mount Kenya using a series of nested plots sized from 25 to 100 m2. The α-diversity was low for all plot sizes (4.8–7.8 and 12.8 species per one and 100 m2, respectively). Comparative analysis of α-, β- and γ-diversity across 22 plant communities from five Mountain regions (Mount Kenya, European Alps, Caucasus, Tibet, New Zealand Alps) revealed that area of mountain system was the only significant variable shaping the local richness; this effect became stronger with increasing spatial scale. Beta-diversity, by contrast, showed neither latitudinal trends nor significant correlation with other geographical or climatic variables. We conclude that the total area of mountain system is one of the main factors determining the regional species pool and, ultimately, the local diversity of alpine plant communities (the “echo-effect”). Small area and isolation of Mt. Kenya are considered as the main reasons for low local richness of its afro-alpine vegetation.

Numerous studies of terrestrial orchids have demonstrated widespread partial mycoheterotrophy, particularly the possibility of obtaining organic matter from surrounding trees through a common fungal network. Fungi are also widespread in epiphytic orchid roots, but there have been no attempts to determine if epiphytes accept organic matter from the living stems of their phorophytes. We hypothesise that such transfer does not exist because epiphytes and phorophytes harbour different fungal communities. To test this hypothesis, we tagged three short Randia sp. trees with 13C-enriched CO2 and examined 13C transfer from the phorophyte into the epiphytic orchids Grosourdya appendiculata, Dendrobium oligophyllum and Gastrochilus sp. in Cat Tien National Park, (South Vietnam, Cat Tien National Park, plot size approx. 1 ha). The coincidence of fungal sequences in the orchid roots and in the branches on which they grew was also examined. We did not detect 13C label moving from phorophytes to epiphytes. Using Illumina sequencing, 162 fungal operational taxonomic units (OTUs) were detected. The fungal communities were significantly different between the roots of epiphytes and branches of phorophytes, although no strict fungal specificity at the species level was found in either epiphytes or phorophytes.

Alpine lichen heaths are polydominant, low-productive communities where lichens and, at some localities, the dwarf shrub Vaccinium vitis-idaea prevail. To analyse the role of herbaceous dominants in the structure of alpine heaths, we established a removal experiment. We tested (1) whether dominant graminoids and forbs differ in their effects on species richness, phytomass, and abundance of individual species; and (2) which remaining species are able to replace the removed dominants. Permanent plots were established in 1996 in the Teberda Reserve (the Northwestern Caucasus, Russia) at 2750 m a.s.l. with four treatments: (1) control, (2) forb removal, (3) graminoid removal, (4) graminoid and forb removal. Target species were clipped every year to avoid regrowth. We counted the shoot numbers of all vascular plants yearly from 1996 to 2009. In 2010, we harvested the aboveground phytomass. We used mixed-effects models to assess the responses of the remaining species and phytomass fractions to the removal. The biomass of the removed dominants was almost compensated for by the remaining species, but due to diffuse competition none of the subordinate species became a new dominant. Graminoid removal reduced community weighted mean leaf dry matter content and litter accumulation. Species number per plot completely recovered after graminoid, not forb removal. Shoot numbers of Antennaria dioica, Arenaria lychnidea, Campanula tridentata, Ranunculus oreophilus, and Trifolium polyphyllum showed positive responses to graminoid removal. Anemone speciosa shoot numbers decreased after graminoid removal. In alpine heath, graminoid dominants contribute more to community structure than forb dominants.

Questions Festuca varia grasslands occupy extensive areas in the alpine belt of the Caucasus. In the Teberda Reserve the dominant, narrow-leaved grasses Festuca varia and Nardus stricta contribute up to 56% and 22%, respectively, to the total biomass of the community. How does community composition and structure change after removal of the dominant, and is any species able to replace dominants in abundance and function? Location Teberda State Biosphere Reserve, northwestern Caucasus, Russia. Methods We experimentally removed F. varia and N. stricta (as single dominants and both together). After 20 yr of treatment we compared the expected increase in species richness per plot, above-ground phytomass, community biomass-weighted mean SLA and leaf DMC, as well as the inter-annual dynamics of functional groups and the most abundant species. Results Dominant removal led to a decrease in litter after removal of F. varia and of both dominants, and a decrease in total phytomass after removal of both dominants. Biomass of dominants did not respond to the treatments, however N. stricta increased shoot number after F. varia removal. Non-dominant narrow-leaved grasses increased in all the treatments, both in biomass and shoot number. Community biomass-weighted SLA increased in all the treatments, and leaf DMC decreased. Conclusions Dominants play a key role in alpine F. varia grasslands and determine the functional structure and composition of the community. Species from other functional groups and, remarkably, species from the same group, are not able to completely replace them. Traits of F. varia, as the main dominant, control community-weighted leaf traits and litter accumulation.

Intraspecific variability of the traits is usually less than interspecific, but directions of inter-and intraspecific variation along environmental gradients are not well studied. For 17 alpine species we test a hypothesis that the direction of intraspecific variation in leaf traits among different communities along an environmental gradient coincides consistently with community weighted mean (CWM) trait variation at the community level along the same gradient. We obtained two groups of leaf traits according to their response to CWM and topographic (snow depth and snow melt) gradients. For leaf mass and area intraspecific variation corresponded to CWM variation among communities. SLA, water content and leaf thickness patterns within species changed directly among communities according to the toposequence (snowmelt gradient). These results are well expressed for forbs, but mostly they were not significant for graminoids. For leaf area we obtained opposite response of forbs and graminoids to snowmelt gradient. Forbs increased, but graminoids decreased leaf area when snow depth increased. Intraspecific trait variation across natural gradients does not necessarily follow that for interspecific or community-level variation.

Predicting climate change impact on ecosystem structure and services is one of the most important challenges in ecology. Until now, plant species response to climate change has been described at the level of fixed plant functional types, an approach limited by its inflexibility as there is much interspecific functional variation within plant functional types. Considering a plant species as a set of functional traits greatly increases our possibilities for analysis of ecosystem functioning and carbon and nutrient fluxes associated therewith. Moreover, recently assembled large-scale databases hold comprehensive per-species data on plant functional traits, allowing a detailed functional description of many plant communities on Earth. Here, we show that plant functional traits can be used as predictors of vegetation response to climate warming, accounting in our test ecosystem (the species-rich alpine belt of Caucasus mountains, Russia) for 59% of variability in the per-species abundance relation to temperature. In this mountain belt, traits that promote conservative leaf water economy (higher leaf mass per area, thicker leaves) and large investments in belowground reserves to support next year's shoot buds (root carbon content) were the best predictors of the species increase in abundance along with temperature increase. This finding demonstrates that plant functional traits constitute a highly useful concept for forecasting changes in plant communities, and their associated ecosystem services, in response to climate change.

Temperature is increasing at unprecedented rates across most of the tundra biome. Remote-sensing data indicate that contemporary climate warming has already resulted in increased productivity over much of the Arctic, but plot-based evidence for vegetation transformation is not widespread. We analysed change in tundra vegetation surveyed between 1980 and 2010 in 158 plant communities spread across 46 locations. We found biome-wide trends of increased height of the plant canopy and maximum observed plant height for most vascular growth forms; increased abundance of litter; increased abundance of evergreen, low-growing and tall shrubs; and decreased abundance of bare ground. Intersite comparisons indicated an association between the degree of summer warming and change in vascular plant abundance, with shrubs, forbs and rushes increasing with warming. However, the association was dependent on the climate zone, the moisture regime and the presence of permafrost. Our data provide plot-scale evidence linking changes in vascular plant abundance to local summer warming in widely dispersed tundra locations across the globe. © 2012 Macmillan Publishers Limited. All rights reserved.

Questions: What are the water economy strategies of the dominant subarcticbryophytes in terms of colony and shoot traits? Can colony water retentioncapacity be predicted from morphological traits of both colonies and separateshoots? Are suites of water retention traits consistently related to bryophytehabitat and phylogenetic position?Location: Abisko Research Station, North Sweden.Methods: We screened 22 abundant subarctic bryophyte species from diversehabitats for water economy traits of shoots and colonies, including desiccationrates, water content at field capacity, volume and density (mgcm 3 )ofwater-saturated and oven-dried patches, evaporation rate (g 1m 2 s )andcellwallthickness.Therelationshipsbetweenthesetraitsandshootandcolonydesiccationrates were analysed with Spearman rank correlations. Subsequent multivariate(cluster followed by PCA) analyses were based on turf density, turf and shootdesiccation rate, cell wall thickness and amount of external and internal water.Results:Individualshootproperties,i.e.leafcellwallproperties,waterretentioncapacity and desiccation rate, did not correspond with colony water retentioncapacity. Colony desiccation rate depended on density of water-saturatedcolonies, and was marginally significantly negatively correlated with speciesindividual shoot desiccation rate but not related to any other shoot or colonytrait. Multivariate analyses based on traitsassumed to determine colony desicca-tion rate revealed six distinct species groups reflecting habitat choice andphylogenetic relationships.Conclusions: General relationships between shoot and colony traits as deter-minants of water economy will help to predict and upscale changes inhydrological function of bryophyte-dominated peatlands undergoing climate-induced shifts in species abundance, and feedbacks of such species shifts onpermafrost insulation and carbon sequestration functions.IntroductionBryophytesareimportantcomponentsofmany ecosystems.Their relative abundance often exceeds that of vascularplants and Sphagnum species in particular create a specificenvironment in extensive peatland areas (Longton 1997;Vitt 2000; Rydin & Jeglum 2006; Cornelissen et al. 2007).When abundant, bryophytes contribute considerably toforest evapotranspiration (Heijmans et al. 2004) and regula-tion of ecosystem hydrology (Clymo & Hayward 1982;Beringer et al. 2001), control carbon regulation (Goulden C Bisbee et al. 2001; Bergeron et al. 2009), modifysoilprocessesandmicrobialactivity(Gornalletal.2007)andcreate a microenvironment for vascular plant germination(Serpe et al. 2006) and growth (Groeneveld et al. 2007).

Questions: Mycorrhizae may be a key element of plant nutritional strategies and of carbon and nutrient cycling. Recent research suggests that in natural conditions, intensity of mycorrhizal colonization should be considered an important plant feature. How are inter-specific variations in mycorrhizal colonization rate, plant relative growth rate (RGR) and leaf litter decomposability related? Is (arbuscular) mycorrhizal colonization linked to the dominance of plant species in nutrient-stressed ecosystems? Location: Teberda State Biosphere Reserve, northwest Caucasus, Russia. Methods: We measured plant RGR under mycorrhizal limitation and under natural nutrition conditions, together with leaf litter decomposability and field intensity of mycorrhizal colonization across a wide range of plant species, typical for alpine communities of European mountains. We applied regression analysis to test whether the intensity of mycorrhizal colonization is a good predictor of RGR and decomposition rate, and tested how these traits predict plant dominance in communities. Results: Forb species with a high level of field mycorrhizal colonization had lower RGR under nutritional and mycorrhizal limitation, while grasses were unaffected. Litter decomposition rate was not related to the intensity of mycorrhizal colonization. Dominant species mostly had a higher level of mycorrhizal colonization and lower RGR without mycorrhizal colonization than subordinate species, implying that they were more dependent on mycorrhizal symbionts. There were no differences in litter decomposability. Conclusions: In alpine herbaceous plant communities dominated by arbuscular mycorrhizae, nutrient dynamics are to a large extent controlled by mycorrhizal symbiosis. Intensity of mycorrhizal colonization is a negative predictor for whole plant RGR. Our study highlights the importance of mycorrhizal colonization as a key trait underpinning the role of plant species in carbon and nutrient dynamics in nutrient-limited herbaceous plant communities.

We studied long-term (25-31 years) dynamics of alpine communities at the Teberda Reserve, NW Caucasus, Russia, to test the following hypotheses: (1) lower altitude species increase and high altitude species decrease their abundance as a consequence of climate warming; (2) such changes in abundance are more significant in communities with short growth season (due to persistent snow cover) compared to exposed communities; (3) species with similar changes in abundance have similar functional traits. Four alpine communities with different positions in relief were considered in order of winter snow cover: alpine lichen heaths (ALH), Festuca varia grasslands (FVG), Geranium-Hedysarum meadows (GHM), and snowbed communities (SBC). The altitudinal distribution of species significantly predicted the direction and degree of changes in species abundance in GHM (p < 0.001), SBC (p < 0.02) and FVG (p < 0.05) with high altitude species decreasing and low altitude species increasing their abundance. Mean altitudes of significantly decreasing species exceeded that of increasing species by ca. 100-130 m in FVG, GHM and SBC. There were no species traits or trait combinations that consistently predicted their changing abundance in ALH, FVG and SBC. In GHM increasing species tended to have leaves with higher SLA (i.e. softer leaves) and lower root nitrogen content. The observed dynamic processes may be caused partly by recent climate warming, although slow recovery from historic grazing pressure may also play a role. Regardless of the causes driving the plant species' upward shift, communities experiencing high snow accumulation (SBC, GHM) seem to be more vulnerable to changes in structure and composition. © 2013 Swiss Botanical Society.

We compared aboveground phytomass structure and community weighed mean leaf traits (leaf area and specific leaf area) in alpine plant communities of Tibet (alpine shrub meadows and alpine bogs, grazed and fenced) and the Caucasus (al­pine lichen heaths, Festuca varia grasslands, Geranium ­ Hedysarum meadows, alpine snowbeds and alpine fens). We tested, if (1) the communities at least partly show functional convergence, (2) the mean community biomass weighed traits vary in accordance with position along a catena, and (3) grazing influences community functional structure. To reveal the pattern of functional structure we run Detren­ded Correspondence Analysis with the biomass of functional groups as variables and plots as cases. Position along a catena was the main driver, and the alpine fens of both Tibet and the Caucasus were the most similar in functional structure. Community biomass weighed specific leaf area increased with water availability and from grass­dominated to frequently disturbed forb­dominated communities.