Bryophyte Cover Research Articles

Plant Traits and Community Metrics across a Snowmelt Gradient at Alpine Snowbank Sites on Mt. Washington, New Hampshire

In northeastern North America, alpine snowbank communities are rare plant assemblages that form in sheltered sites above treeline where late-lying snow provides insulation from late-season frosts and a longer-lasting source of water. We measured snowpack and studied community composition and plant traits at the species and community scales across the snowmelt gradient at snowbank sites on Mt. Washington, New Hampshire. We used nonmetric multidimensional scaling ordination and analysis of similarity to examine community composition across the snowmelt gradient and measured plant traits (height, leaf dry matter content, leaf area, and specific leaf area) of four focal species (Carex bigelowii, Chamaepericlymenum canadense, Clintonia borealis, and Maianthemum canadense). We assessed trait variability of the four focal species across the snowmelt gradient and evaluated community-weighted mean trait values and phenotypic plasticity between snowbank core and edge habitats. Analysis of similarity indicated that vascular plant diversity increased (p < 0.001), lichen and bryophyte cover decreased (p < 0.001; p < 0.025), and community-weighted mean leaf area increased (p < 0.001) in the core of snowbank communities where melting dates were later. Analysis of similarity indicated that vascular plant communities varied significantly across the snowmelt gradient. The transition in community composition and trait values across the snowmelt gradient are indicative of changing environmental conditions and ecosystem functions, though more research is needed to determine the extent to which phenotypic plasticity and ecotypic uniqueness influence trait expression of snowbank species. Genetic analysis may be necessary to evaluate population dynamics among isolated alpine communities, which may be vulnerable to climate change or displacement by exotic or lowland species.

Determinants of bryophyte assemblages in traditionally managed grasslands of the Carpathian Mts

Questions Although bryophytes play an important role in grassland ecosystems, environmental factors that drive bryophyte assemblages were rarely studied, especially in low-intensity traditional grasslands. Therefore, using fine-scale data on bryophyte assemblages in traditionally managed secondary grasslands, we studied the relative importance of several sets of environmental drivers (related to topography, soil properties, landscape, and management) of: (i) taxonomic and functional compositions; and (ii) cover and species richness of bryophyte communities. Location Central and Eastern Europe, Carpathian Mountains, 15 sites with preserved traditional management practices distributed in Romania (six sites), Ukraine (four), Slovakia (two), Austria (one), Hungary (one) and Poland (one). Methods Fine-scale data on soil, topography, and vegetation structure as well as on bryophyte assemblages (taxonomic and functional composition, cover, species richness) were collected in 10-m2 plots. We used stratified random sampling to select six 10-m2 plots of traditionally managed grasslands in each of the 15 sites (n = 90). Climatic and landscape variables were extracted from online databases and available maps. Detailed data on present and historical land use were obtained from parcel owners. To assess the effect of drivers on bryophyte taxonomic and functional composition we applied canonical correspondence analysis (CCA) and redundancy analysis (RDA), respectively; for bryophyte species richness and bryophyte cover we used GLMMs. Forward stepwise variable selection procedure was used to find best set of drivers for each of the analyses. Results Topographic (microrelief and solar radiation) and soil-related factors (cover of stones and rocks, soil depth, moisture), as well as the cover of the herb layer and bare soil were the strongest drivers of bryophyte taxonomic composition. Among the management- and landscape-related variables only mean size of grassland parcels within 1-km2 plot surroundings and grazing by horse were included in the CCA model explaining in total 25.9% of variation in species composition. Bryophyte functional composition was explained by a similar set of variables (RDA explained 27.3% of variation in functional composition) including additionally cover of gravel and burning. Solar radiation (negative effect) and management stability (positive effect) were the strongest drivers of bryophyte cover. Management stability had the strongest effect (positive) on bryophyte species richness, followed by grassland age (negative) and microrelief (positive). Conclusions Taxonomic and functional composition of bryophyte assemblages as well as bryophyte cover in traditional grasslands were determined mainly by variables related to moisture and light availability. Management-related factors seem to be at least as equally important as abiotic factors for bryophyte species richness and cover. Our results suggest that for maintaining bryophyte-rich grasslands one should also consider stability of grassland management, that is, temporal continuity and regularity of management practices applied.

Why are the aesthetics of modest mosses highly valued in Japanese gardens?

Japanese gardens emphasize on the aesthetic value of bryophytes, a major ground cover in moss gardens. Using medieval and early modern documents, this study analyzed the evolution of moss gardens and their aesthetic value by elucidating how moss usage changed over time. Twenty documents written from the 11th to the 19th centuries were surveyed. According to these documents, mosses were used as supplemental ground cover around the 11th century. After the 15th century, mosses were intentionally selected and planted in Zen gardens (gardens established at Zen temples) and Roji (gardens attached to tea ceremony rooms). Zen gardens provide monks with a feeling of being deep in the mountains. Roji particularly emphasizes Wabi-Sabi aesthetics, which embrace the opposite of conventional beauty, such as aging processes and tranquility. These concepts in Zen and Roji gardens are associated with bryophyte-covered landscapes. This is because these landscapes suggest a mountain-like ambiance, the passage of time, and tranquility in Japan. These associations suggest that the importance of bryophyte cover in gardens might have increased with the development of Zen and Roji gardens—specifically, mosses came to be used as major ground cover after the establishment of Roji. Moreover, given that Zen Buddhism underlies the establishment of Wabi-Sabi aesthetics, it might have been the impetus for the development of moss gardens.

Forest fires have long-term effects on the composition of vascular plants and bryophytes in Scots pine forests of hemiboreal Estonia

Since fire frequency is expected to increase globally due to climate change, it is important to understand its effects on forest ecosystems. We studied the long-term patterns in species diversity, cover and composition of vascular plants and bryophytes after forest fire and the site-related factors behind them. Research was carried out in northwestern Estonia, using a chronosequence of Scots pine ( L.) stands, located on nutrient poor sandy soils, where fires had occurred 12, 23, 38, 69, 80 and 183 years ago. In every stand three 100 m vegetation plots were established to collect floristic and environmental information. The effects on floristic characteristics of time since fire, light, and soil variables were evaluated with linear mixed models, followed by backward variable selection. Compositional variation was analysed with non-metric multidimensional scaling, Multi-response Permutation Procedures, and Indicator Species Analysis. Altogether, 31 vascular plant and 39 bryophyte species were found in vegetation plots. The cover of the vascular plant and bryophyte layers increased with a longer time since fire. Soil and light variables impacted the richness of several vascular plant and bryophyte groups, whereas only the richness of liverworts and dwarf-shrubs correlated with time since fire. Considerable compositional differences were observed in vascular plant and bryophyte assemblages between recently vs. long-time ago burned stands. To conclude, time since fire significantly impacted compositional patterns of vascular plants and bryophytes in pine forests on nutrient poor soils, although time-related trends in species richness were less evident.Pinus sylvestris2

The epiphytic bryophyte succession of Picea orientalis forests on the Kumbet High Plateau (Giresun-Turkey)

In this study, the epiphytic bryophyte succession of Picea orientalis forests on the K?mbet High Plateau (Giresun-Turkey) were studied. A total of 21 epiphytic bryophyte species were determined (16 mosses and 5 liverworts). The epiphytic bryophyte communities were sampled in 60 sample plots taken from the trunks of Picea orientalis, each of which was 20 ? 20 cm in size. The Index of Ecological Significance (IES), based on a combination of the relative frequency and mean cover of epiphytic bryophytes, was used to evaluate the abundance of bryophyte communities in epiphytic habitats on the tree trunks. In addition, multivariate classification techniques (TWINSPAN and DECORANA) were used to classify the community structures in successional stages. TWINSPAN divided the 60 sample plots into two main groups: a) the lower base communities (LB) and b) the middleupper zone communities (MU). Moreover, the middle-upper zone communities (MU) were divided into two sub-groups associated with the successional gradient (MU1 and MU2). DECORANA classified these communities along the ordination axes 1 and 3 related to the height gradient of Picea orientalis and the moisture (from mesic to xeric) gradient of the epiphytic habitat. While Exsertotheca crispa, Cynodontium fallax, Lewinskya striata, and Habrodon perpusillus were only found on old spruce trees, Drepanium fastigiatum was only found on young trees and Lophocolea heterophylla was only found on middle-aged trees.

How Does the pH of Tree Bark Change with the Presence of the Epiphytic Bryophytes from the Family Orthotrichaceae in the Interaction with Trunk Inclination?

The pH of tree bark is affected by many factors, amongst them epiphytic bryophytes changing in their active state environment. Thus, we hypothesized that bryophytes can change bark acidity, dependently of the inclination of the branches, as inclination affect the water regime and particle deposition. We measured the pH under bryophyte cushions and compared it to nearby naked bark. Additionally, we compared results with experimental bark covering with neutral cover. We found that the pH of naked bark declines with decreasing inclination of trunks. Although bryophyte cover did not generally change the pH of the bark, there was a significant interaction with inclination: with higher inclination, bryophytes decrease the pH reaction of bark, while with lower inclination they increase it. One possible explanation may lie in changes to alkaline particle deposition, or conversely in the acidification of the bark by leaching. In addition, an experiment with a neutral cover showed that naked bark covering would substantially increase pH. As, on average, bryophytes do not change the pH of bark, there can be mutual interference between the alkalizing effect of the bark cover itself and the acidifying biological effect of bryophytes.

Epiphytic bryophytes and lichens in Graz and Podgorica (Austria and Montenegro)

Sündhofer, R., Mayrhofer, H., Werth, S., Dragićević, S. & Berg, C. 2021. Epiphytic bryophytes and lichens in Graz and Podgorica (Austria and Montenegro). – Herzogia 34: 299 –326. In Graz (Austria) and Podgorica (Montenegro), epiphytic lichens and bryophytes were studied in 2017 based on a standardized approach. On 165 trees in Graz, 27 bryophyte and 38 lichen species were determined. In Podgorica, on 161 trees, 29 bryophyte and 52 lichen species were found. The mean epiphytic cover in Graz was significantly higher. Mean bryophyte cover was higher in Podgorica, mean lichen cover was significantly higher in Graz. Many species occurred in both cities. The mean species number per plot was nearly the same in both cities. Five urban habitat types were distinguished: parks, garden city, residential area, industrial area, and areas along rivers. Mean species numbers of lichens and bryophytes differed significantly between phorophyte species. The tree trunk circumference had no significant impact on the species number. Bryophytes preferred a northern and western exposition on the tree trunk. For lichens, this pattern could not be confirmed. Agonimia opuntiella, Caloplaca cerinelloides, Candelariella viae-lacteae, Catapyrenium psoromoides, and Mycobilimbia epixanthoides were reported for the first time in Montenegro.

Tree genotypes affect rock lichens and understory plants: examples of trophic-independent interactions.

Genetic variation in foundation tree species can strongly influence communities of trophic‐dependent organisms, such as herbivorous insects, pollinators, and mycorrhizal fungi. However, the extent and manner in which this variation results in unexpected interactions that reach trophic‐independent organisms remains poorly understood, even though these interactions are essential to understanding complex ecosystems. In pinyon–juniper woodland at Sunset Crater (Arizona, USA), we studied pinyon (Pinus edulis) that were either resistant or susceptible to stem‐boring moths (Dioryctria albovittella). Moth herbivory alters the architecture of susceptible trees, thereby modifying the microhabitat beneath their crowns. We tested the hypothesis that this interaction between herbivore and tree genotype extends to affect trophic‐independent communities of saxicolous (i.e., growing on rocks) lichens and bryophytes and vascular plants beneath their crowns. Under 30 pairs of moth‐resistant and moth‐susceptible trees, we estimated percent cover of lichens, bryophytes, and vascular plants. We also quantified the cover of leaf litter and rocks as well as light availability. Four major findings emerged. (1) Compared to moth‐resistant trees, which exhibited monopodial architecture, the microhabitat under the shrub‐like susceptible trees was 60% darker and had 21% more litter resulting in 68% less rock exposure. (2) Susceptible trees had 56% and 87% less cover, 42% and 80% less richness, and 38% and 92% less diversity of saxicolous and plant communities, respectively, compared to resistant trees. (3) Both saxicolous and plant species accumulated at a slower rate beneath susceptible trees, suggesting an environment that might inhibit colonization and/or growth. (4) Both saxicolous and plant communities were negatively affected by the habitat provided by susceptible trees. The results suggest that herbivory of moth‐susceptible trees generated litter at high enough rates to reduce rock substrate availability, thereby suppressing the saxicolous communities. However, our results did not provide a causal pathway explaining the suppression of vascular plants. Nonetheless, the cascading effects of genetic variation in pinyon appear to extend beyond trophic‐dependent moths to include trophic‐independent saxicolous and vascular plant communities that are affected by specific tree–herbivore interactions that modify the local environment. We suggest that such genetically based interactions are common in nature and contribute to the evolution of complex communities.

Stand-Level Variation Drives Canopy Water Storage by Non-vascular Epiphytes Across a Temperate-Boreal Ecotone

Epiphytes, including bryophytes and lichens, can significantly change the water interception and storage capacities of forest canopies. However, despite some understanding of this role, empirical evaluations of canopy and bole community water storage capacity by epiphytes are still quite limited. Epiphyte communities are shaped by both microclimate and host plant identity, and so the canopy and bole community storage capacity might also be expected to vary across similar spatial scales. We estimated canopy and bole community cover and biomass of bryophytes and lichens from ground-based surveys across a temperate-boreal ecotone in continental North America (Minnesota). Multiple forest types were studied at each site, to separate stand level and latitudinal effects. Biomass was converted into potential canopy and bole community storage on the basis of water-holding capacity measurements of dominant taxa. Bole biomass and potential water storage was a much larger contributor than outer canopy. Biomass and water storage capacity varied greatly, ranging from 9 to &amp;gt;900kg ha–1 and 0.003 to 0.38 mm, respectively. These values are lower than most reported results for temperate forests, which have emphasized coastal and old-growth forests. Variation was greatest within sites and appeared to reflect the strong effects of host tree identity on epiphyte communities, with conifer-dominated plots hosting more lichen-dominated epiphyte communities with lower potential water storage capacity. These results point to the challenges of estimating and incorporating epiphyte contributions to canopy hydrology from stand metrics. Further work is also needed to improve estimates of canopy epiphytes, including crustose lichens.

Deer exclusion unveils abiotic filtering in forest understorey plant assemblages.

The role of deer (family Cervidae) in ecosystem functioning has traditionally been neglected by forest ecologists due to the animal's scarcity in most parts of the northern hemisphere. However, the dramatic rebound in deer populations throughout the 20th century has brought deer browsing to the forefront of forest ecological questioning. Today there is ample evidence that deer affect tree regeneration, understorey plant and animal diversity, and even litter decomposition. However, the mechanisms underlying the effects of deer on forest ecosystems remain unclear. Among others, the relative role of abiotic factors versus biotic interactions (e.g. herbivory) in shaping plant assemblages remains largely unknown. We used a large-scale experiment with exclosures distributed along abiotic gradients to understand the role of black-tailed deer (Odocoileus hemionus sitchensis) on the forest understorey on the Haida Gwaii archipelago (western Canada), a unique context where most of the key ecological effects of deer presence have already been intensively studied. Our results demonstrate that 20 years of deer exclusion resulted in a clear increase in vascular plant richness, diversity and cover, and caused a decline in bryophyte cover. Exclusion also unveiled abiotic (i.e. soil water availability and fertility) filtering of plant assemblages that would otherwise have been masked by the impact of abundant deer populations. However, deer exclusion did not lead to an increase in beta diversity, probably because some remnant species had a competitive advantage to regrow after decades of over browsing. We demonstrated that long-term herbivory by deer can be a dominant factor structuring understorey plant communities that overwhelms abiotic factors. However, while exclosures prove useful to assess the overall effects of large herbivores, the results from our studies at broader scales on the Haida Gwaii archipelago suggest that exclosure experiments should be used cautiously when inferring the mechanisms at work.

The analysis of environmental space conditions for bryoflora forming in artificial pine communities of the Buzuluksky pine forest and the Krasnosamarsky forest

The paper deals with ecological conditions and peculiarities of bryoflora of artificial pine communities of the Buzuluksky pine forest and the Krasnosamarsky forest. The authors have revealed that the pine plantings of the Buzuluksky pine forest are characterized by a lower soil moisture and nitrogen supply than similar communities of the Krasnosamarsky forest in accordance with the criteria of D.N. Tsyganov scales. In addition, all communities belonging to the same territory show differences in the acidity and salt regime of soils as well as in moisture contrasts. The differences seem to be the result of a specific manifestation of parallel multidirectional successional processes (afforestation and steppe formation). For the bryofloras of the studied artificial pine communities, a significant similarity level (Czekanowski-Srensen index of 0,7) and close values of the projective cover and vitality of bryophytes have been shown. However, the substrate preferences of bryophytes are significantly different: 85% of the species grow on soil in the Buzuluksky pine forest, while 52% of the species grow on soil and 39% of the species grow on decaying wood in the Krasnosamarsky forest. In addition, more intensive sporulation of bryophytes has been noted in artificial pine communities of the Krasnosamarsky forest and the share of dominant species in the projective cover is 47,7% there, and their share is 83,4% in the Buzuluksky pine forest. The authors have suggested that genetic polymorphism should underlie the revealed differences in the species similarity of bryofloras. Its manifestation is influenced, among other things, by the stage of ecological succession of plant communities in which bryophytes grow. It is the result of the implementation of strategies for bryophytes adaptation to existing conditions and reflects the stage of bryoflora formation.

Are Juglans neotropica Plantations Useful as a Refuge of Bryophytes Diversity in Tropical Areas?

Neotropical montane forests are considered biodiversity hotspots, where epiphytic bryophytes are an important component of the diversity, biomass and functioning of these ecosystems. We evaluated the richness and composition of bryophytes in secondary successional forests and mixed plantations of Juglans neotropica. In each forest type, the presence and cover of epiphytic bryophytes was registered in 400 quadrats of 20 cm × 30 cm. We analyzed the effects of canopy openness, diameter at breast height (DBH) and forest type on bryophyte richness, using a generalized linear model (GLM), as well as the changes in species composition using multivariate analysis. Fifty-five bryophyte species were recorded, of which 42 species were in secondary forests and 40 were in mixed plantations. Bryophyte richness did not change at forest level; however, at tree level, richness was higher in the mixed plantation of J. neotropica compared to the secondary forests, due to the presence of species adapted to high light conditions. On the other hand, bryophyte communities were negatively affected by the more open canopy in the mixed plantation of J. neotropica, species adapted to more humid conditions being less abundant. We conclude that species with narrow microclimatic niches are threatened by deforestation, and J. neotropica plantations do not act as refuge for drought-sensitive forest species present in secondary forests.

Forest floor bryophyte and lichen diversity in Scots pine and Norway spruce production forests

Bryophytes and lichens are two main components of the forest floor vegetation. They provide essential ecosystem services, including nutrient recycling and water regulation. Here, we contrast the species richness, cover and community composition of forest floor bryophytes and lichens in Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) dominated production forests. The study sites were located in the hemiboreal zone of southern Sweden, and represented early-, mid- and late rotation stands. Our aim was to examine the potential consequences for forest floor biodiversity from the decreasing use of Scots pine production forests in this region.Whereas Scots pine and Norway spruce stands did not differ in bryophyte cover, we found a higher cover of lichens in Scots pine stands, and highest in the intermediate aged stands. Also the species richness of lichens was higher in the Scots pine stands, while bryophyte species richness was higher in the Norway spruce stands. Differences in canopy cover and associated light transmittance to the forest floor appears to be important drivers for distinctive different forest floor communities in the Scots pine and Norway spruce stands, as revealed by Non-Metric Multidimensional Scaling (NMDS). Mean Ellenberg indicator values for bryophytes and lichens showed that species associated with Scots pine stands were characterized by their tolerance of brighter conditions, higher insolation, and better adaptation to a continental climate. Norway spruce stands instead had a comparably larger proportion of species tolerating lower light, but also indicators of higher available nutrient levels, humidity, and pH. The outcome of the Ellenberg indicator species analysis, as well as the larger cover of lichens,and adaptations to drought found among some mosses, revealed that forest floor communities are shaped by different environmental factors in Scots pine and Norway spruce production stands. These environmental differences, and the quantified shifts in forest floor communities identified in this study, indicate the large shifts in understory bryophyte and lichen species composition and abundance that is likely to occur if Scots pine stands are converted to Norway spruce.

Anthropogenic disturbance modifies long‐term changes of boreal mountain vegetation under contemporary climate warming

AbstractAimsAccelerating high‐latitude climate warming drives shrub expansion in open landscapes and alters species distributions and compositions of plant communities. Simultaneously, various land use practices cause disturbance to the vegetation. However, not much documentation exists on how long‐term intensive land use disturbance modifies high‐latitude vegetation under climate warming. Here, we study how the composition of boreal mountain plant communities has changed during three decades in response to heavy land use disturbance, related to ski resort construction and management, and how these changes compare to those observed in adjacent less disturbed communities.LocationIso‐Syöte, Finland.MethodsWe resurveyed vegetation along four elevational gradients (240–426 m a.s.l.) on a boreal mountain in 2013–14. After the original study in 1980, half of the gradients were subjected to continuous heavy land use disturbance, while the other half remained only slightly disturbed. All the gradients experienced a similar amount of macroclimatic warming over time. We analysed temporal changes in plant group covers, species richness and species’ elevational range means in relation to disturbance levels and elevation.ResultsUnder slight disturbance, the cover of shrubs increased on the originally open upper slopes and elevational range means of several species shifted upward. In contrast, heavy disturbance resulted in a uniform, yet modest, shrub cover increase along the whole elevational gradient and promoted both up‐ and downward shifts of species. Bryophyte cover decreased considerably over time, regardless of the disturbance level. Species richness increased throughout, yet more under heavy disturbance.ConclusionsLong‐term changes in boreal mountain vegetation are substantially influenced by heavy land use disturbance compared to less disturbed sites where the vegetation changes are more comparable to those expected under a warmer climate. Therefore, along with the climatic effects, land use effects on vegetation are important to consider in management actions and in projections of future vegetation.

Assessing the strength of climate and land-use influences on montane epiphyte communities.

Epiphytes, air plants that are structurally dependent on trees, are a keystone group in tropical forests; they support the food and habitat needs of animals and influence water and nutrient cycles. They reach peak diversity in humid montane forests. Climate predictions for Central American mountains include increased temperatures, altered precipitation seasonality, and increased cloud base heights, all of which may challenge epiphytes. Although remaining montane forests are highly fragmented, many tropical agricultural systems include trees that host epiphytes, allowing epiphyte communities to persist even in landscapes with lower forest connectivity. I used structural equations models to test the relative effects of climate, land use, tree characteristics, and biotic interactions on vascular epiphyte diversity with data from 31 shade coffee farms and 2 protected forests in northern Nicaragua. I also tested substrate preferences of common species with randomization tests. Tree size, tree diversity, and climate all affected epiphyte richness, but the effect of climate was almost entirely mediated by bryophyte cover. Bryophytes showed strong sensitivity to mean annual temperature and insolation. Many ferns and some orchids were positively associated with bryophyte mats, whereas bromeliads tended to establish among lichen or on bare bark. The tight relationships between bryophytes and climate and between bryophytes and vascular epiphytes indicated that relatively small climate changes could result in rapid, cascading losses of montane epiphyte communities. Currently, shade coffee farms can support high bryophyte cover and diverse vascular epiphyte assemblages when larger, older trees are present. Agroforests serve as valuable reservoirs for epiphyte biodiversity and may be important early-warning systems as the climate changes.

Wood Ash Application Reduces Bryophyte Cover and Changes Species Composition in a Norway Spruce (Picea abies) Plantation

Return of wood ash from power plants to plantations makes it possible to recycle nutrients, counteract acidification, and to reduce economically costly waste deposition of the wood ash. However, current legislation restricts the amount of wood ash that can be applied and it is desirable to increase the allowed application dose, if possible, without negative effects on the plantation ecosystems. Here, we applied wood ash in levels corresponding to 0, 3, 9, 15, 30, and 90 t ash ha−1 and monitored the effect of the different ash doses on bryophytes in a Norway spruce (Picea abies) plantation with a dense bryophyte cover dominated by Hypnum jutlandicum, Dicranum scoparium, and Pleurozium schreberi. We used two complementary methods, image analysis, and pinpoint registration during a three-year period. To our knowledge, we are the first to apply this combined effort, which provides a much more exhaustive description of the effects than the use of each method separately. Moreover, the inclusion of a wide range of different wood ash levels enabled us to establish detailed dose-response relationships, which previous authors have not presented. The bryophyte cover decreased with increasing ash level with concomitant changes in species composition. At ash doses above the currently allowed 3 t ha−1, the ash significantly reduced the bryophyte cover, which only re-established very slowly. With increasing wood ash dose, the dominating species changed to Brachythecium rutabulum, Ceratodon purpureus, and Funaria hygrometrica. We conclude that application of more wood ash in spruce plantations than currently allowed will reduce total cover of bryophytes and cause a pronounced change in bryophyte species composition. These changes will in particular harm bryophyte species with specific environmental requirements and generally impair the bryophyte cover as habitat for invertebrates and its economic value for moss harvesting.

Tree height as the main factor causing disappearance of the terricolous lichens in the lichen Scots pine forests

The lichen Scots pine forests habitats are undergoing rapid disappearance across Europe. Due to the semi-natural character of this habitat and an increase of the nitrification as a result of air pollution, determination of factors responsible for the decrease in lichen field layer cover requires a comprehensive approach. Our study aimed to investigate environmental factors necessary for the determination of active protection measures in order to maintain this vulnerable habitat. Specifically, we aimed to investigate: 1) the environmental factors influencing lichen cover in the lichen Scots pine forests of Bory Tucholskie National Park; 2) the differences in habitat variables between sites with lichen-rich and bryophyte-rich field layers. In our study, we used vegetation and microhabitat properties data collected over three years of surveys, as well as ALS LiDAR data. Our results indicated that lichen and bryophyte cover, tree height, tree cover, thickness of organic matter layer, soil temperature and soil water content differed between lichen-rich and bryophyte-rich sites. We found a significant negative relationship between lichen cover recorded within the field layer and tree height. The lichen-rich field layer developed better in areas with lower tree height and thinner layer of organic matter, which created a favorable habitat conditions for lichen development. Our research revealed the previously unknown impact of tree height for the development of lichen field layer. These findings can be used to plan the active conservation measures of lichen Scots pine forests.

Native plant turnover and limited exotic spread explain swamp biotic differentiation with urbanization

AbstractQuestionsDoes urbanization promote biotic differentiation or homogenization of swamp plant communities? What is the contribution of natives and exotics to swamp response to urbanization?LocationQuebec City, Canada.MethodsPlant communities of 34 swamps located in low, moderately or highly urbanized landscapes were sampled, and species classified into three exclusive groups: native wetland, native upland and exotic plants. Urbanization’s influence on the richness of each plant group was assessed using mixed models. Between‐site compositional similarities were calculated to identify variations in beta diversity with urbanization level using tests for homogeneity in multivariate dispersion. Beta diversity was further partitioned into species replacement and richness difference for each plant group. Finally, the relationships of ten environmental variables representing soil water saturation and microtopography with plant assemblages were determined by redundancy analysis.ResultsAlthough the richness of exotics increased with urbanization intensity, revealing increasing propagule pressure, it remained six to 27 times lower compared to the richness of natives, which remained stable with urbanization. On the other hand, beta diversity increased with urbanization, with higher dissimilarities in species composition between highly urbanized swamps than between low‐urbanized ones. This pattern resulted from high species replacement among natives, while richness difference mainly contributed to exotic beta diversity. Changes in plant assemblages were mostly associated with bryophyte cover and soil drainage and red mottle size, suggesting that hydrological conditions likely acted as a strong driver of swamp plant community response to urbanization.ConclusionsSwamp plant communities experienced biotic differentiation with increasing urbanization. This differentiation pattern likely was linked to the unpredictable effect of urbanization on hydrological regimes, which promoted high native turnover while limiting exotic spread. Long‐term monitoring is recommended to ensure that exotics do not outcompete natives through time. Designing sustainable cities requires a greater understanding of the multifaceted effect of urbanization on biodiversity.

Role of the bryophytes in substrate revitalization on a post-technogenic salinized territory

This work aims to investigate the role of the bryophyte cover in substrate revitalization on a post-technogenic salinized territory. The influence of the moss cover on the organic carbon content, actual acidity, redox potential, and the content of the main ecological and trophic groups of microorganisms in the substrate of the tailings storage of the Stebnyk Mining and Chemical Enterprise "Polymineral" was investigated. Bryophytes significantly affect the tailings storage saline substrates. They colonize areas with a very strong and strong degree of salinity, which are unsuitable for other plants. It was indicated that pioneer moss species promote the accumulation of organic matter in saline substrates of the tailings storage. Under moss turfs, the amount of organic carbon increased 2.2–5.0 times, compared with its content in the uncovered substrate. The high variability of the organic matter content is determined by the species characteristics of mosses, primarily their life form. The dense-turf species Didymodon rigidulus and Pthychostomum pseudotriquetrum var. bimum accumulated the most organic matter. The thickness of the litter under the moss turf of these species was much greater than in Barbula unguiculata and Funaria hygrometrica, which form loose turf. We assessed the specificity of the accumulation of organic carbon in the turfs of the studied mosses. It founded that most organic matter accumulated in the dead parts of the moss turf. In the green parts of the shoots of these moss species the amount of organic carbon was 3–4 times less, which indicates a relationship between litter capacity and content of carbon in the substrate under moss turfs. We investigated the influence of mosses on the actual acidity of the tailings storage substrate. Moss turfs promote the increase of acidity of the aqueous solution of the tailings substrate by 0.2–0.5 units. The tailings storage substrates are characterized by a reduction regime. The redox potential of the substrate under moss cover significantly depended on the species characteristics of mosses. Under the moss cover, the redox potential increased by 1.2–1.4 times, compared with the index for the substrate without moss cover. We studied the influence of moss cover on microbial biomass and the quantity of some ecological-trophic groups of microorganisms in the substrates of the tailings storage. The amount of microbial biomass under moss turfs increased depending on the degree of the substrate salinization and the species characteristics of the mosses. In areas with a very high degree of salinization under the moss turfs of Didymodon rigidulus and Funaria hygrometrica, the microbial biomass index increased almost two times, compared with the uncovered substrate. We found a significant increase in the quantity of the main ecological and trophic groups of microorganisms (saprophytes, cellulose-destroying bacteria, oligonitrophils and nitrogen fixers) in the substrate under the moss cover. Thus, pioneer moss species have a complex effect on the saline substrate of tailings storage. They accumulate organic matter, increase the acidity of the upper layer, improve the redox regime of the substrate and promote the development of soil microbiota.

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.