Alpine Heath Research Articles

COVERater-A Free Application for Training Researchers to Accurately Estimate Species Cover in Terrestrial and Aquatic Ecosystems.

Visual estimates of cover are widely used among ecologists, from describing vegetation communities to tracking and monitoring species' abundance. However, despite the known bias associated with visual estimates, no standardised training is available to improve these measurements. We developed a free online training tool, the COVERater, that effectively teaches users to visually estimate the percent cover of species in a variety of ecosystems (including alpine heath, arid lands, coral reefs, temperate reefs and wetlands). Prior to training, users with prior professional experience estimated species cover to an average inaccuracy of 5.2%, while users with no experience estimated cover to an average inaccuracy of 7.6%. COVERater training took an average of 31 min and 68 images, and reduced the estimate inaccuracy of users with no prior experience to 5.2%. There was no significant loss of estimate accuracy over 100 days following training. The COVERater can be used anywhere in the world, by data collectors of all experience levels, for projects spanning all spatial scales. By providing researchers with standardised training, our application can reduce variation in cover estimates that arise from human biases, allowing for comparable estimates across global collaborative projects and data syntheses. We encourage all relevant scientists to include COVERater training in their protocols to quantify cover with greater accuracy, improve the veracity of their results and make better inferences about our biosphere.

Seventy-five years of vegetation change after fire in Tasmanian alpine heathland

Context Alpine ecosystems are threatened by warming and an associated increase in fire frequency. There is a gap in our knowledge of succession in Tasmanian alpine heath more than 50 years after fire. The literature suggests that the alpine successional progression usually involves decreasing rates of change, decreasing differences among fire ages, ongoing transitions among shrub species, ongoing transitions from some lifeforms/species to others, and that warming results in increases in species richness. Aims We test for these tendencies up to 75 years from fire in alpine vegetation on kunanyi/Mount Wellington, Tasmania, Australia. Methods We documented the changes in vegetation structure and composition between 1998 and 2022 in plots on either side of an alpine fire boundary in the alpine heathland and used earlier data and observations to extend the record of change after fire to 75 years. We put these changes in the context of the only area of alpine vegetation that was not burnt in 1947 or later. Key results The area last burnt in 1947 exhibited declines in all lifeform covers between 1998 and 2022. All lifeforms except tall shrubs and mat shrubs declined in cover in the area last burnt in 1962. By 2022, shrub cover in the 1962-burnt area had not attained equivalence with the area last burnt in 1947. Herbs had the most dramatic decline in both fire-age classes. There were few shrub seedlings in 2022. All but six taxa, three being exotic, were observed in both the plots and previous broader surveys. Increases in species richness caused by the upward migration of lower-elevation species were not observed. The long-unburnt patch lacked the major dominant of the 1947-burnt plots, namely Orites acicularis, and was dominated by a gymnosperm absent from most of the mountain. Conclusions Succession follows the initial floristic composition model. The differences in trajectories from the 1947 and 1962 fires could possibly be due to desiccation or abrasion damage from increasing wind speeds and temperatures. There are strong indications of further potential change in the absence of fire. Implications The slow rate of recovery and its on-going nature emphasise the importance of keeping fire out of this vegetation type.

Chemical composition of plant leaves as a functional sign of the formation of alpine plant communities

The content of C, N, P and the N:P and C:N ratios in plant leaves were studied in four alpine phytocenoses of the northwestern Caucasus to find out 1) how much the species found in them differ in chemical composition from random samples from the local flora; 2) how important the values of these characteristics are for dominance; 3) how phylogenetically conservative they are. The leaves of plants of alpine heaths and variegated fescue meadows contain less, and leaves of geranium-kopec meadows and alpine carpets contain more nitrogen compared to a random sample. Dominants of productive geranium-penny meadows contain more nitrogen than non-dominant species; for other communities, the opposite dependence is noted. Components of all communities, except alpine carpets, contain less phosphorus in their leaves compared to a random sample. The dominant species of alpine heaths contain less, and geranium-penny meadows contain more phosphorus in their leaves compared to non-dominant species. The C:N ratio in leaves is higher than random in species of alpine heaths and variegated fescue meadows and lower in other communities. The dominant species have higher C:N ratios compared to the others in all communities, except for geranium-penny meadows. The N:P ratio was higher than random in species of all communities except variegated fescue meadows. All characters except the C:N ratio have significant phylogenetic signal.

South American mountain ecosystems and global change – a case study for integrating theory and field observations for land surface modelling and ecosystem management

ABSTRACT Background Plot-based monitoring has yielded much information on the taxonomic diversity and carbon (C) storage in tropical lowland forests of the Amazon basin. This has resulted in an improved understanding of the relationship between lowland forest biomass dynamics and global change drivers, such as climate change and atmospheric CO2 concentration. Much less attention has been paid to the mountain ecosystems of South America that comprise montane forests and alpine vegetation (páramo, puna, high Andean grasslands, wetlands, and alpine heath). This vegetation complex provides a variety of ecosystem services and forms a natural laboratory along various physiographic, geological and evolutionary history/biogeography, and land use history gradients. Aims Here, we review existing empirical understanding and model-based approaches to quantify the contribution of mountain ecosystems to ecosystem service provision in the rapidly changing socioecological setting of the South American mountains. The objective of this paper is to outline a broad road map for the implementation of mountain vegetation into dynamic global vegetation models (DGVM) for use in Earth System Models (ESM), based on our current understanding of their structure and function and of their responsiveness to global change drivers. We also identify treeline processes, critical in mountain ecosystems, as key missing elements in DGVMs/ESMs, and thus explore in addition a treeline model. Methods Stocktaking of the availability of empirical data was undertaken from eight research sites along the Andes and in south-eastern Brazil. Out of eight sites, two (one each in Venezuela and Brazil) had some climate, ecological and ecophysiological data potentially suitable to parametrise a DGVM. Tree biomass data were available for six sites. A preliminary assessment of the Joint UK Land Environment Simulator (JULES) DGVM was made to identify gaps in available data and their impacts on model parametrisation and calibration. Additionally, the potential climate-determined elevation of the treeline was modelled to check the DGVM for its ability to identify the transition between the montane forest and alpine vegetation. Results Outcomes of the evaluation of the JULES land surface model identified the following key processes in montane forests: temperature-related decrease in net primary production, respiration, and allocation to above-ground biomass and increase in soil C stocks with elevation. There was a variable agreement between simulated biomass and those derived from field measurements via allometric equations. Conclusions We identified major gaps between data availability and the needs for process-based modelling of South American mountain vegetation and its dynamics in DGVMs. To bridge this gap, we propose a transdisciplinary network, composed of members of the theoretical/modelling and empirical scientific communities, to study the natural dynamics of mountain ecosystems and their responses to global change drivers locally, regionally and at the continental scale, within a social-ecological system framework. The work presented here forms the basis for the design of data collection from field measurements and instrumental monitoring stations to parametrise and verify DGVMs. The network is designed to collaborate with and complement existing long-term research initiatives in the region and will adopt existing standard field protocols. Complementary protocols will ensure compatibility between field data collection and data needed for process-based and empirical models.

Impact of ambient temperature, precipitation and seven years of experimental warming and nutrient addition on fruit production in an alpine heath and meadow community

Alpine and polar regions are predicted to be among the most vulnerable to changes in temperature, precipitation, and nutrient availability. We carried out a seven-year factorial experiment with warming and nutrient addition in two alpine vegetation communities. We analyzed the relationship between fruit production and monthly mean, maximum, and min temperatures during the fall of the pre-fruiting year, the fruiting summer, and the whole fruit production period, and measured the effects of precipitation and growing and thawing degree days (GDD & TDD) on fruit production. Nutrient addition (heath: 27.88 ± 3.19 fold change at the end of the experiment; meadow: 18.02 ± 4.07) and combined nutrient addition and warming (heath: 20.63 ± 29.34 fold change at the end of the experiment; meadow: 18.21 ± 16.28) increased total fruit production and fruit production of graminoids. Fruit production of evergreen and deciduous shrubs fluctuated among the treatments and years in both the heath and meadow. Pre-maximum temperatures had a negative effect on fruit production in both communities, while current year maximum temperatures had a positive impact on fruit production in the meadow. Pre-minimum, pre-mean, current mean, total minimum, and total mean temperatures were all positively correlated with fruit production in the meadow. The current year and total precipitation had a negative effect on the fruit production of deciduous shrubs in the heath. GDD had a positive effect on fruit production in both communities, while TDD only impacted fruit production in the meadow. Increased nutrient availability increased fruit production over time in the high alpine plant communities, while experimental warming had either no effect or a negative effect. Deciduous shrubs were the most sensitive to climate parameters in both communities, and the meadow was more sensitive than the heath. The difference in importance of TDD for fruit production may be due to differences in snow cover in the two communities.

Changes in plant composition and diversity in an alpine heath and meadow after 18 years of experimental warming

Changes in plant composition and diversity in an alpine heath and meadow after 18 years of experimental warming

Long-term natural dynamics of an alpine lichen heath in the Teberda State Biosphere Reserve, northwestern Caucasus

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.

Visitors off the trail: Impacts on the dominant plant, bryophyte and lichen species in alpine heath vegetation in sub-arctic Sweden

Alpine ecosystems are under increasing pressure due to tourism and recreational activities. When leaving designated trails as is frequently observed, visitors can cause unintentional damage to vegetation. This study investigated the effect of human trampling on the dominant species of vascular plants, bryophytes and lichens along an infrequently used hiking trail in an alpine ecosystem in sub-arctic Sweden. The hypothesis tested was that proximity to the trail (as an effect of more people leaving the trail for a short distance compared to a longer distance) causes a decrease in species with low resistance to trampling. With a greater decrease in taller forbs and shrubs than in graminoids and prostrate plants, a greater decrease in lichen than in bryophyte species, and a change in vegetation composition. The results showed that proximity to the trail did not cause a decrease in the majority of dominant species, with none of the eight most dominant vascular plants showing any significant effects of proximity to the trail. One bryophyte species (Dicranum elongatum) among the six most commonly found decreased with proximity to the trail. Three lichen species (Cladonia arbuscula, Cladonia uncinalis, Ochrolechia frigida) among the eight most common species decreased with proximity to the trail. There was no evidence that taller species decreased with proximity to the trail, although the deciduous shrub Betula nana showed a tendency for a decrease. Proximity to the trail caused a greater decrease in lichen species than in bryophyte species. Multivariate analyses showed that distance from trail and transect direction had significant effects on overall vegetation composition. The level of low-intensity trampling recorded indicates that current numbers of hikers at the site can be sustained for longer periods with minimum impact on vascular plant species, but to get a more general understanding of the impact of low-intensity trampling data from additional sites are needed.

Impact of Ambient Temperature, Precipitation and Seven Years of Experimental Warming and Nutrient Addition on Fruit Production in an Alpine Heath and Meadow Community

Impact of Ambient Temperature, Precipitation and Seven Years of Experimental Warming and Nutrient Addition on Fruit Production in an Alpine Heath and Meadow Community

Bryophyte cover and richness decline after 18 years of experimental warming in alpine Sweden.

Climate change is expected to affect alpine and Arctic tundra communities. Most previous long-term studies have focused on impacts on vascular plants, this study examined impacts of long-term warming on bryophyte communities. Experimental warming with open-top chambers (OTCs) was applied for 18 years to a mesic meadow and a dry heath alpine plant community. Species abundance was measured in 1995, 1999, 2001 and 2013. Species composition changed significantly from original communities in the heath, but remained similar in mesic meadow. Experimental warming increased beta diversity in the heath. Bryophyte cover and species richness both declined with long-term warming, while Simpson diversity showed no significant responses. Over the 18-year period, bryophyte cover in warmed plots decreased from 43 % to 11 % in heath and from 68 % to 35 % in meadow (75 % and 48 % decline, respectively, in original cover), while richness declined by 39 % and 26 %, respectively. Importantly, the decline in cover and richness first emerged after 7 years. Warming caused significant increase in litter in both plant communities. Deciduous shrub and litter cover had negative impact on bryophyte cover. We show that bryophyte species do not respond similarly to climate change. Total bryophyte cover declined in both heath and mesic meadow under experimental long-term warming (by 1.5–3 °C), driven by general declines in many species. Principal response curve, cover and richness results suggested that bryophytes in alpine heath are more susceptible to warming than in meadow, supporting the suggestion that bryophytes may be less resistant in drier environments than in wetter habitats. Species loss was slower than the decline in bryophyte abundance, and diversity remained similar in both communities. Increased deciduous shrub and litter cover led to decline in bryophyte cover. The non-linear response to warming over time underlines the importance of long-term experiments and monitoring.

Seed bank as a persistent problem in matrix population models: From uncertainty to certain bounds

Errors in the construction of matrix population models may lead to erroneous conclusions from modeling case studies, and neglecting the seed bank as a stage in the stage-structured model is a kind of ‘persistent problem’ common to many models of plant species. The problem arises due to uncertainties in the seed-related parameters that cannot be reliably estimated from empirical data. We investigate the consequences that including a seed bank into the underlying life cycle graph may have on λ1, the dominant eigenvalue of the calibrated matrix in the “no-seeds” model. Vital rates of that model were calibrated on a time series of data of the 'identified individuals’ type gained in our former, 11-year case study on a local population of Androsace albana, a short-lived perennial inhabiting alpine heaths. The calibration has resulted in 10 successive population projection matrices expressed in rational numbers, with a variety of λ1s distant from 1 by various amounts in both directions. To include the seed bank, we propose an integer-valued formalism with the following three unknown S-related parameters: S(t), the number of dormant seeds able to germinate at the current year of observation, t; Sp(t), the number of seeds produced this year, and Sm(t), the total number of seeds lost this year for various reasons. These preserve the rational form of all the other vital rates and holding the calibration equations true in the integer numbers, too. Some observable traits of A. albana plants help establish certain finite ranges of the three S-related parameters, and they enable finding the ensuing ranges of model outcomes by merely enumerating all the feasible triples. In this way, we get answers to pertinent questions about the λ1 of the seed model vs. its “no-seeds” counterpart and give a mathematical explanation of what we have obtained. An important conclusion is that the seed bank can principally not change the population growth into decline, nor vice versa, within the feasible ranges of parameters.

Resource Regulation of the Regrow Capacity of Plants in Alpine Heaths: Factorial Experiment

The regrowth of the aboveground biomass of certain plant species after complete or partial defoliation in highlands can depend on competition with neighboring plants, as well as on the level of availability of soil resources, primarily mineral nutrients (especially N and P). A 3-year full-factorial experiment on the effect of three defoliation regimes (control and single and double mowing at the soil level per season), enrichment of soil with N and P, and removal of neighboring plants (competition reduction) on the shoot number and aboveground biomass of three plant species (Anemone speciosa, Festuca ovina, and Oxytropis kubanensis) in alpine heaths was carried out (in total, 12 variants in 10 replications). It is shown that the removal of competing vegetation in low-productive communities of alpine heaths does not contribute to the biomass recovery after defoliation, unlike the addition of NP fertilizers. The regrow of a nitrogen-fixing legume did not depend on the availability of soil resources.

Functional Diversity of Alpine Plant Communities: A Case Study of Plant Height

The parameters of functional diversity are studied on the example of plant height for four alpine communities (alpine lichen heaths, Festuca varia grasslands Hedysarum-Geranium meadows, and alpine snowbed communities) in Teberda Reserve of the northwestern Caucasus. The work tests the hypothesis that, when plants that use different volumes of air, a low volume of the environment is used more evenly than a high volume. It was assumed that the divergence in plant height is more pronounced in meadow communities, where the competitive relationship is stronger and the level of production is higher. For the four main types of phytocenoses (alpine heaths, Festuca varia grasslands Hedysarum-Geranium meadows, alpine snowbeds), data were obtained on the average height of the plant species forming them, the biomass of individual species, and the weighted average plant height in the communities. The indices of functional richness, evenness, and divergence were calculated based on these data. It is shown that taking into account the abundance of species in the community significantly affects the values of average height and indices of functional diversity. Contrary the a priori hypothesis, it was found that the value of evenness is significantly lower at a low air volume occupied by the community (alpine snowbeds) than for a high volume (Festuca varia grasslands). The functional divergence in alpine snowbed communities with low productivity is higher than that in the more productive meadow phytocenoses, e.g. Festuca varia grasslands. The aboveground production positively correlated with functional richness in the aggregate analysis of all data, but this correlation is not detected within communities. Functional evenness is not related to community production. An unimodal relationship between the index of functional-divergence and aboveground biomass was shown only for the Festuca varia grasslands (the maximal divergence is observed on plots with average biomass).

Геоботанические исследования на Кавказе: обзор материалов Международной конференции «Флора и заповедное дело на Кавказе: история и современное состояние изученности» (Пятигорск, 22–25 мая 2019 г.)

The International conference “Flora and conservation in the Caucasus: history and current state of knowledge” dedicated to the 130-year anniversary of the Perkalsky Arboretum took place at 22–25 of May 2019 in Pyatigorsk (Stavropol Territory) on the base of the Pyatigorsk Museum of local lore and natural history. The participants were from 11 cities of Russia and 7 Republics of the Caucasus and represented 14 institutions. Proceedings of the conference were published by the beginning of the meeting the book of abstracts includes 49 papers on the study of vascular plants, bryophytes, lichens and fungi, plant communities, as well as the protection of rare and endangered species, unique plant communities, and ecological problems in the Caucasus. The following geobotanical topics were highlighted in 13 papers: forest communities (3 reports), meadow and steppe vegetation (2), xeric open forests (2), communities of ecotone areas (1), structure of populations of rare plant species (3), as well as the history and current status of nature protected areas (2). The great emphasis has been focused on the study of floristic composition and plant populations. Thus, the conference showed that very few studies от vegetation are currently carried out in the Caucasus, and a lot of districts are not affected by the research. The greatest attention is paid to forest vegetation while meadow, steppe, alpine heath and xerophytic communities are studied rather poorly. Besides, there are “white spots” — mire, floodplain and aquatic vegetation. In nowadays, when the anthropogenic impact on the plant cover of the Caucasus is intensively increasing, it is especially important to study natural undisturbed communities preserved in protected natural areas. Another important issue is the conservation of the unique vegetation cover of the whole Caucasus. Thus, the study of vegetation of this region opens a wide field for researchers using various methods of modern plant science.

Overview of the population state of Savin Juniper (Juniperus sabina) in the Rila Mt.

Juniperus sabina L. is a rare plant species protected by the Biological Diversity Law in Bulgaria. It is included in the Red List of Bulgarian Vascular plants (Petrova and Vladimirov 2009) and the Red Data Book of Republic of Bulgaria under the “Critically Endangered” category (Peev et al. 2015). The shrub communities with the participation of the Savin juniper are considered as priority habitats in the Alpine and Boreal heaths on the territory of the European community. They are included in the national lists of protected habitats in the Bulgarian Biodiversity Law and in the Habitats Directive (92/43/EEC). In the Rila Mt. to date there is only one known habitat of the shrub communities of J. sabina, in the area between Beli Iskar Village and along Cherni Iskar River, at 1000–1200 m elevation. Aim: The aim of this study was to assess the population state of J. sabina, to evaluate the presence of serious threats contributing to long-term habitat degradation, and to design actions for the protection and long-term restoration of the shrub communities of Savin juniper. Material and methods: The route and stationary methods were used for selected objects. The monitoring and assessment of the population status has been carried out in accordance with the approved methodologies of the National Biodiversity Monitoring System of the Executive Environment Agency (EEA 2019). Results: According to the classic syntaxonomic classification, the J. sabina communities in the Rila Mt. belong to the class Vaccinium-Piceetea excelsae. They represent very rare, relict communities including several interesting plants and high fungal diversity and a number of rare, and sensitive species recorded by this study. In the Rila Mt. communities with Savin juniper are very small and of limited distribution. The potential of the species to spread to other localities or to conquer new territories is extremely low. One of the most threatening factors is overgrazing. In addition, traces of illegal camping and pollution with construction and municipal waste were found. Conclusion: The results of this study could provide support for better management and the conservation of biodiversity in the Rila Mt.

Lichens facilitate seedling recruitment in alpine heath

AbstractQuestionsHow do mat thickness, physical structure and allelopathic properties of terricolous mat‐forming lichens affect recruitment of vascular plants in dwarf‐shrub and lichen heath vegetation?LocationThe mountains of Dovrefjell, central Norway.MethodsIn autumn, seeds of ten vascular plant species were collected and sown in a common garden experiment with mats of six lichen species and bare soil controls as experimental treatments. We recorded growing season soil temperature and moisture, and seedling recruitment and growth after one year. The effect of lichen secondary compounds on germination was tested in a growth chamber experiment and compared to the lichen–plant interactions detected under field conditions.ResultsThe lichen mats buffered extreme soil temperatures and soil drying in dry weather, with soils below the thickest mats (Cladonia stellaris and C. rangiferina) experiencing the lowest temperature fluctuations. Seedling recruitment and seedling growth in the field and seed germination in the lab were species‐specific. Seedling recruitment rates were overall higher within lichen mats than on bare soil, but the c. 6.5‐cm‐thick mats of C. stellaris reduced recruitment of many species. The lab experiment suggested no overall strong effect of lichen allelopathy on seed germination, and effects on seed germination were only moderately correlated with the lichen–plant interactions observed for seedling recruitment in the field.ConclusionsIn harsh environments like alpine dwarf‐shrub and lichen heaths, the presence of lichens and the resulting amelioration of the microclimate seem more important for vascular plant recruitment than are allelopathic effects often reported in lab experiments. We might therefore expect most terricolous lichens, depending on the plant species in focus, to facilitate rather than hamper the early stages of plant recruitment into lichen‐dominated arctic‐alpine heath vegetation.

Functional group contributions to carbon fluxes in arctic-alpine ecosystems

ABSTRACTOngoing responses to climate change in arctic-alpine ecosystems, including the increasing dominance of deciduous shrubs, involve major shifts in plant functional group composition. Because rates of photosynthesis and respiration and their responses to temperature may vary among plant functional groups, a better understanding of their contributions to carbon fluxes will help improve predictions of how ecosystem changes will affect carbon source-sink relations in globally important tundra regions. We used a sequential harvest method to estimate growing season functional group contributions to net ecosystem exchange (NEE), ecosystem respiration (ER), and gross photosynthesis (GP) in alpine heath-, meadow-, and Salix-dominated shrub communities. We also partitioned ER into aboveground and belowground components in all three communities. Belowground efflux was the dominant component of ER in the heath and meadow communities (63 percent and 88 percent of ER, respectively) but contributed only approximately 40 percent of ER in the shrub community. The dominant functional group in each community contributed most to aboveground exchanges. Estimates for cryptogams were uncertain, but indicated a minor role for bryophytes and lichens in overall exchange. The results of our novel method of partitioning gas-exchange measurements suggest strong differences in the relative proportions of soil versus aboveground respiration and in the contributions of different functional groups in the net carbon exchange of three important arctic-alpine community types, with implications for changes in carbon dynamics as these systems respond to environmental change.

Effects of herbaceous plant functional groups on the dynamics and structure of an alpine lichen heath: the results of a removal experiment

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.

The Relationship of Dominance and Evenness with Productivity and Species Richness in Plant Communities with Different Organization Models

The relationship between dominance and evenness in plant communities organized according to different models—competitive (alpine, subalpine, and low-mountain grasslands), stress-tolerant (alpine heaths and scrubs, subalpine fens, steppes, the forest herbaceous layer), and ruderal—has been analyzed in the Western Caucasus and Ciscaucasia. No correlation between evenness (dominance) and productivity has been revealed in communities of any type. The correlation between dominance and species richness is negative and, in most cases, linear, being stronger in competitive and ruderal than in stress-tolerant cenoses. The correlation between evenness and species richness in grassland communities (the competitive model) is strong, positive, and linear, while this correlation in ruderal and stress-tolerant communities is weak or absent.

Two decades of altered snow cover does not affect soil microbial ability to catabolize carbon compounds in an oceanic alpine heath

Snow strongly affects ecosystem functioning in alpine environments with potential carry-over effects outside of snow periods. However, it is unclear whether changes in snow cover affect microbial community functioning in summer. In a field experiment, we tested whether manipulation of snow cover affected the functional capabilities of the microbial community either directly, or indirectly through concomitant changes in the vegetation. While 23 years of differential snow depth and persistence fundamentally changed the vegetation composition, the microbial community's ability to catabolize a range of carbon compounds was not altered. Instead, soil moisture content was the key driver of carbon catabolism by the microbial community.