Bryophyte Composition Research Articles

Small-scale pattern of bryoflora in Mediterranean temporary ponds: hints for monitoring

In the Mediterranean region temporary ponds are classified among the most biologically and biogeographically interesting ecosystems. Despite their important ecological functions in those environments, bryophytes are neglected or undervalued in most monitoring and conservation actions. We analyzed the data to understand if (i) environmental variables had an influence on the composition of bryophytes in temporary ponds (dbRDA); (ii) there are differences among sites and ponds, in terms of species composition (PERMANOVA); (iii) bryophytes respond to the water table fluctuation, showing a typical small-scale spatial zonation and comprehend if there are species or life form/strategies typical of those belts (PCoA). Bryophytes are distributed in concentric belts (outer, central, inner) according to their tolerance to floods: we observed a gradient from the outer belt, mainly composed by colonist and perennial such as Pottiaceae and Brachytheciaceae, to the more humid inner one where annual shuttle such as Ricciaceae dominates. We found significant species associated with belts, such as Tortella squarrosa in the outer belt, Fossombronia caespitiformis in the central belt, and Riccia canaliculata in the inner belt. The presence of indicator species and the distribution of dominant life form/strategies in the belts allow to monitor over time the changes in the flood level.

Perbandingan Komposisi Tumbuhan Lumut Epifit Pada Hutan Alam, Kebun Kopi dan Kebun Teh di Sepanjang Gradien Ketinggian Gunung Ungaran, Jawa Tengah

Study on the impact of differences in altitude and land use changes was conducted in natural forest, coffee and tea plantations in along altitudinal gradient of Ungaran mountain from 750 to 2040 m a.s.l. The objective of this study were to compare composition of epiphytic bryophytes species in third sites. Epiphytic bryophytes sampling were done in plots 20 x 30 cm were applied on height of tree betwen 0-2 m. A total of 103 species of epiphytics bryophytes were identified, involve 58 species of mosses (Bryophyta Division) and 45 species of liverworts (Marchantiophyta Division). The composition of bryophytes in natural forest is more diverse than in coffee and tea plantations. Lejeunaceae have the highest number of species. There are seven life forms of epiphytic bryophytes in the present study i.e. Turf, Cushion, Mats, Wefts, Dendroid, Pendant and Fans. The most common is Mats and Turf form, while Pendant and Dendroid form only found in natural forest. Key words: Bryophytes, epiphytes, altitude, land use changes, life form

The effects of rock climbing on cliff‐face vegetation

AbstractQuestionWhat are the effects of rock climbing on diversity, abundance and composition on cliff‐face vegetation along environmental and use gradients typical of modern climbing?LocationNew River Gorge National River, WV, US.MethodsWe compared species richness, abundance and composition of vascular plants, bryophytes and lichens on 79 pre‐established rock climbs and 32 unclimbed ‘control’ sites across potential climb‐use intensity and cliff structure using linear models, residual analysis and NMDS ordination.ResultsDifferences in species richness and abundance associated with potential climb‐use intensity and cliff structure were variable across taxonomic groups. Linear models indicated that cliff angle was the strongest explanatory variable of species richness and abundance for all three taxonomic groups. Once the effects of biophysical variables were modelled, analysis of the residuals indicated that potential climbing‐use intensity had a small but negative effect on species richness and abundance of vascular plants (range 3–6%), no effect on bryophytes (0%) and a substantial effect on lichens (range 10–12%). Similarly, NMDS ordination indicated that cliff angle, canopy height and aspect were the primary drivers of species composition. We observed no change in community composition due to climbing.ConclusionsOther studies have observed significant impacts of climbing on vegetation at the base of cliffs. Here, we observe that potential climbing‐use intensity has some impact on species richness and abundance of vascular plants and more significant impacts on lichens, however cliff angle is a fundamental control on cliff vegetation. Because of the challenge in sampling steep and overhanging cliffs, we recommend that climbers be directly involved in the assessment, monitoring and management of cliff resources in order to ensure that the full range of biophysical conditions of cliff ecosystems are considered.

Which environmental factors best explain variation of species richness and composition of stream bryophytes? A case study from mountainous streams in Madeira Island

Freshwater ecosystems and their associated organisms are among the most endangered in the world. Here we focus on bryophyte communities in streams characterized by a strong altitudinal gradient. The main purpose of this study was to determine the most important environmental variables affecting bryophyte species richness and composition and to quantify the relative importance of different sets of environmental variables. We studied bryophyte communities at upstream, intermediate and downstream sections of 16 streams distributed on the northern and southern side of Madeira Island in the Atlantic Ocean. We found that bryophyte species richness and composition was strongly affected by the measured environmental variables. Of particular importance were the geomorphological and hydrological variables as well as the chemical and physical properties of the streams. Temperature (or altitude) was highly correlated with other variables reflecting clear altitudinal gradients. While upstream communities were generally in a rather natural condition and rich in bryophyte species, downstream communities had less species and often anthropogenically modified stream banks. Due to the confounding of downstream areas with human influences and other variables such as temperature, the separate effects of these variables are not known. The relationship and the distributions of some bryophyte species/communities across the altitudinal range suggest that these riparian bryophyte communities may be sensitive to global warming.

Bryophyte communities in the Amazon forest are regulated by height on the host tree and site elevation

Summary Community composition of epiphytic bryophyte communities, sampled systematically in nine localities across 2800 km from east to west of the Amazon forest, was mostly explained by their height zone along the vertical microenvironmental gradient from the base to the top of the host tree. Despite the lack of correlation between geographical distance and dissimilarity in species composition, communities within the same locality were significantly more similar than communities from different localities in all height zones, with the highest values of similarity found between outer canopy communities. While height zone on the host tree explained most of the variation in species composition at local scale, elevation and temperature were the variables most strongly related to species composition at a geographical scale. Using the concepts of meta/local community of the Neutral Theory of Biodiversity and Biogeography, we showed that establishment limitation was strongest at the extremes of the vertical gradient. We estimated that communities of the tree base and the outer canopy drew individuals from outside the habitat species pool at a rate of 0.28 and 0.22, respectively, in contrast with values between 0.55 and 0.76 of other height zones. Our results offered contrasting evidence for the hypothesis that species inhabiting the canopy have higher chances of engaging in long‐distance dispersal events. If the stronger establishment limitation at the extremes of the gradient is not compensated by facilitated dispersal compared to other zones, as our results suggest, communities on the base and on the outer canopy might be, through time, subjected to stronger selection. Synthesis. This study indicated that the community composition of epiphytic bryophytes in the Amazon is mainly regulated by environmental conditions, both at local and at geographical scales. Dispersal, although predominantly local, did not show geographical structure across the area.

Bole bryophyte diversity and distribution patterns along three altitudinal gradients in Yunnan, China

AbstractQuestionWe investigated the bryophyte communities on tree boles along three altitudinal gradients located within different types of forested area to answer the following questions: (1) how many bole epiphytic bryophyte species are there; (2) what are the dominant species; (3) what are the richness patterns of epiphytic bryophyte communities along the altitudinal gradients; and (4) what are the major drivers and conservation implications of these patterns?LocationThree protected forested areas in sub‐montane (Mengla transect: 800–1400 m), montane (Zhenyuan transect: 2000–2600 m) and sub‐alpine (Lijiang transect: 3200–3800 m) regions in Yunnan, SW China.MethodSixty 20 m × 20 m sampling plots were established, five at each of 12 altitudes at 200‐m intervals along the transects. Species composition and cover of bryophytes were investigated from 594 subplots (each 400 cm2) on large tree boles of these plots. One‐way ANOVAs were adopted to test for differences in species diversity among different transects. Multi‐dimensional scaling in two dimension (MDS‐2D) ordinations were conducted to assess similarity of bryophyte communities among study transects and altitudes. Canonical correspondence analysis (CCA) was applied to relate species composition to selected environmental variables.ResultsThe three protected forests in Yunnan harboured 226 epiphytic bryophyte species belonging to 101 genera and 46 families, which were essential components of biodiversity of the entire forest ecosystem. In total, 99% of bryophyte species (224 species) showed varying degrees of local rarity. Smooth mat, fan and turf dominated in the sub‐montane, montane and sub‐alpine forests, respectively. Significantly lower bryophyte species richness was detected in the sub‐montane area, which may be partly attributed to higher temperature, limited water availability and more frequent human disturbance. Epiphytic bryophytes exhibited a hump‐shaped species richness pattern with increasing altitude. Peak richness coincided with highest moisture levels at ca. 2600 m.ConclusionsBased on the presence of a high diversity of bryophytes and a high percentage (99%) of locally rare species growing on tree boles, this study emphasizes the importance of conserving these forests in Yunnan. Additionally, the regional pattern of lower epiphytic bryophyte diversity in warmer, drier areas shown in this study reveals how emerging climate change threatens Yunnan's epiphytic bryophytes.

Coenotic role of bryophytes in the mountain-tundra communities of the plateau Siniy Dol (Kronotsky State Nature Reserve, Eastern Kamchatka)

The coenotic role and floristic composition of bryophytes in mountain tundra communities of the plateau Siniy Dol (Kronotsky State Nature Reserve) were studied. Landscape and vegetation of this part of the reserve is significantly different from the adjacent areas, which are affected by modern volcanism. Dwarf-shrublichen mountain tundra communities are common for the territory. The following associations of the shrub mountain tundra were revealed: Empetretum vacciniosum, Dryadetum punctatae diapensiosum, Loiseleurietum procumbentis fruticulosum and Phyllodocetum caeruleae varioherbosum. The role of bryophytes in the species composition of the mountain tundra communities was analyzed. It is shown that bryophytes are characterized by rather high species diversity in the studied communities, but usually by a small abundance and a low coenotic role in the mountain tundra communities. The list includes 41 moss and 6 liverwort species. Several new species for the Kronotsky State Nature Reserve (Dicranum groenlandicum, Kiaeria blyttii, Oncophorus compactus, Lophozia silvicoloides) and some rare species for the Kamchatka Peninsula (Dicranum brevifolium, D. groenlandicum, Kiaeria blyttii, Lophozia silvicoloides, Warnstorfia tundrae) were found.

Reprint of: Patterns and drivers of species composition of epiphytic bryophytes and lichens in managed temperate forests

Epiphytic bryophytes and lichens are an important component of the endangered forest biota in temperate forests, their diversity and composition patterns being regulated by tree, stand and landscape scale factors. The aim of this study is to improve ecological understanding of such factors in managed coniferous–deciduous mixed forests of Hungary in the context of forest management. In particular, this study investigate the effect of tree species composition, stand structure (tree size distribution, shrub layer and dead wood), microclimate (light, temperature and air humidity), landscape and historical factors on the stand level and tree level composition of epiphytic bryophytes and lichens. The relationships were explored by multivariate methods (Redundancy Analysis, canonical correspondence analysis and variation partitioning) and indicator species analysis. Tree species is among the most important driver of species composition in both organism groups. For bryophytes, the continuity of forest microclimate and the presence of shrub layer are also important, while lichen assemblages are influenced by light availability. Landscape and historical variables were less influential than stand scale factors. On the basis of our results, the main strategy of management focusing on epiphyte diversity conservation should include: (1) the maintenance of tree species diversity in mixed stands; (2) increasing the proportion of deciduous trees (mainly oaks and hornbeam); (3) the maintenance of large trees within the stands; (4) the presence of shrub and regeneration layer; (5) the creation of heterogeneous light conditions.

Bryophyte composition and diversity within anthropogenic habitats in a residential area of Chongqing municipality city

Little is known about bryophyte composition and diversity in habitats created by residential areas. Ours is the first study aiming at gathering baseline information on the bryophyte flora of Chongqing municipality city and providing a scientific basis for evaluation of environmental quality and bryophyte adaptability in residential environments. Based on extensive field work, 84 bryophyte species in 33 genera and 19 families were reported from 23 residential areas in nine districts of Chongqing. Of those, 39.28% of the species belonged to Pottiaceae and Bryaceae, and most of them grew on soil. The most common species were Fissidens bryoides, Haplocladium microphyllum, Hydrogonium majusculum, Taxiphyllum taxirameum and Aneura pinguis. The number of bryophyte species in these 23 residential areas varied from 5 to 25. The similarity of bryophyte species composition between different residential areas was very low, suggesting the presence of distinct habitats and a high diversity among these areas. Turfs were the main life form of bryophytes that we observed. Canonical Correspondence Analysis revealed that the number of residents was the most influential factor in terms of the bryophyte species composition and diversity, followed by the area of green space. Our results suggested that, within cities, residential areas contain important environments for bryophytes. Observed differences in bryophyte composition among residential areas may be attributed to spatial background, urbanization, microhabitat and human disturbance.

The ecological structure of the bryoflora of Wroclaw's parks and cemeteries in relation to their localization and origin

The ecological structure of the flora of 81 bryophytes found in 22 town parks and 6 cemeteries situated within the borders of the Wrocław town has been analyzed in relation to the localization of objects (within the center of the town and its suburbs) and their origin (parks set up in the place of ruins, those built on the site of old cemeteries, objects established within former forests, and parks set up in open, previously rural areas, often as gardens of mansions). In general estimation, the bryoflora of parks and cemeteries appears to be rather ecologically highly specializated - more than 50% of species occurred only on one type of substratum. Epiphytes s.s. occurred rarely. More often bryophytes were noted at the bases and on the trunks of trees, up to 30 cm. Some of the mosses, described in literature as epiphytes, have adapted to terrestrial-epiphytic sites and have been found only at the base of trees. In parks, epigeits were found in abundance on the ground around the base of trees and in shaded lawns. The presence of specialized epixylics was insignificant, although some of the typical forest epixylics were noted, namely <em>Aulacomnium androgynum</em>, <em>Herzogiella seligeri</em> and <em>Dicranum scoparium</em>. However, only parks situated in the suburbs show a high ecological variety of bryoflora, while objects established within the center of the town do not differ in species composition of bryophytes from surrounding built-up areas, despite their origin. Only in the parks situated in the suburbs there was a pronounced presence of forest and meadow species. The factor of park's origin seems to influence the bryoflora's ecological structure and the species richness on objects situated in the suburbs. In the cemeteries a positive correlation between the high number of species, age of monuments and the dimensions of object areas was stated.

Regeneration strategies influence ground bryophyte composition and diversity after forest clearcutting

Natural regeneration with broadleaved species and reforestation with coniferous trees are two widely practiced forest regeneration strategies after timber harvesting. They lead to different tree species composition and may cause different understory biodiversity, but the effects on ground bryophyte composition and diversity are not well-known. We tested whether natural regeneration with broadleaved species and reforestation with spruce induced different diversities of the ground bryophyte populations 20–40 years after old-growth spruce forest clearcutting in the subalpine regions of southwestern China. Differences between natural stands and plantations were compared through the analysis of 13 paired stands, with 78 plots, 390 shrub/herb quadrats, and a total of 1,560 bryophyte quadrats. Naturally regenerated forests were characterized by lower density and cover and lower tree height but higher herbaceous plant height, shrub cover, and bryophyte diversity. They also harbored many more ground bryophytes. The species richness of pleurocarpous mosses and fans, mats, and turfs were significantly higher in naturally regenerated forests. Frequency difference analysis demonstrated that more bryophyte species preferred ground habitats in naturally regenerated forests than in plantations (116 vs. 48 species). The canonical correspondence analysis indicated that stand structure attributes were more important determinants of ground bryophyte diversity and abundance. Natural regeneration and reforestation resulted in large differences in ground bryophyte populations. A larger diversity was observed in the former case, and natural regeneration practices can be an effective measure for the protection of ground bryophyte diversity after clearcutting.

Facilitation vs. competition: Does interspecific interaction affect drought responses in Sphagnum?

The stress-gradient hypothesis (SGH) predicts that the relative importance of competition decreases and facilitation increases with an increase in abiotic stress. In peatlands, Sphagnum faces the threat of drought and differentiates into hummock species (drought-tolerant) and hollow species. Whether interspecific interaction affects the influence of drought on bryophyte composition in peatlands is unknown. We established an experiment by simulating drought and building bryophyte communities with two hummock species (S. palustre and S. capillifolium) and one hollow species (S. fallax). In all three species, drought decreased biomass production, height increment and side-shoot production. Sphagnum stores water in the hyaline cells, and leaf hyaline cell percentage (HCP) in the two hummock species increased with drought while no effect was found in S. fallax, suggesting that adjusting HCP is not an effective response to drought for the hollow species. Morphological traits and carbon and nitrogen contents in hummock species responded more to drought than in the hollow species, indicating a rapid response in phenotypic plasticity is an important strategy to resist drought in the hummock species. The presence of neighboring Sphagnum species, rather than drought, decreased carbon content for all three species. All three bryophytes showed interaction between drought and neighbor in two or more plant traits. Our study, however, did not support SGH, and there were no changes from competition under wet to facilitation under dry treatments in any of the six species combinations. On the contrary, when S. fallax was the target species, a change from facilitation under wet to competition under dry treatments was observed. The results suggest that hummock species can facilitate hollow species in wet environments but they could suppress hollow species under drought conditions by competing for water resources. Both drought and strong competition are the probable reasons why hollow species rarely grow in hummocks.

Nitrogen deposition is negatively related to species richness and species composition of vascular plants and bryophytes in Swiss mountain grassland

Nitrogen (N) deposition is a major threat to biodiversity of many habitats in the lowlands. In mountain habitats, however, the effect of N deposition on biodiversity is not well understood. Here, data from the biodiversity monitoring of Switzerland were used to investigate whether high N deposition is negatively related to species richness and community uniqueness of vascular plants and bryophytes in mountain grassland. The total species diversity, as well as the diversity of three subsets of species (i.e. oligotrophic species, eutrophic species and targeted grassland species according to conservation objectives of the Swiss authorities) were analyzed. Overall, the empirical data from the present study indicate that the currently expert-based range of the critical load of N deposition below which harmful effects on sensitive ecosystems should not occur (upper bound is currently at 20kg Nha−1yr−1) is set too large for mountain hay meadows. Negative relations between N deposition and species richness and community uniqueness in mountain grassland were found already at 10–15kg Nha−1yr−1. The results suggest that the negative effect of N deposition on plant diversity is mainly due to a decrease of oligotrophic plant species and to a lesser extent to an increase in eutrophic plant species. While for bryophytes, the decrease of community uniqueness is related to changes in both oligotrophic and eutrophic species. Furthermore, because plant species richness of target species for conservation was negatively related to N deposition, airborne N deposition is likely to defeat conservation efforts in mountain grassland.

Patterns and drivers of species composition of epiphytic bryophytes and lichens in managed temperate forests

Epiphytic bryophytes and lichens are an important component of the endangered forest biota in temperate forests, their diversity and composition patterns being regulated by tree, stand and landscape scale factors. The aim of this study is to improve ecological understanding of such factors in managed coniferous–deciduous mixed forests of Hungary in the context of forest management. In particular, this study investigate the effect of tree species composition, stand structure (tree size distribution, shrub layer and dead wood), microclimate (light, temperature and air humidity), landscape and historical factors on the stand level and tree level composition of epiphytic bryophytes and lichens. The relationships were explored by multivariate methods (redundancy analysis, canonical correspondence analysis and variation partitioning) and indicator species analysis. Tree species is among the most important driver of species composition in both organism groups. For bryophytes, the continuity of forest microclimate and the presence of shrub layer are also important, while lichen assemblages are influenced by light availability. Landscape and historical variables were less influential than stand scale factors. On the basis of our results, the main strategy of management focusing on epiphyte diversity conservation should include: (1) the maintenance of tree species diversity in mixed stands; (2) increasing the proportion of deciduous trees (mainly oaks and hornbeam); (3) the maintenance of large trees within the stands; (4) the presence of shrub and regeneration layer; (5) the creation of heterogeneous light conditions.

Long‐term and contemporary environmental conditions as determinants of the species composition of bog organisms

Summary Environmental change alters ecosystem processes, minding biogeochemical cycles. These changes are accompanied by shifts in species composition. We predicted that long‐term averages of environmental variables would explain more of the variability in species composition than short‐term assessments, but that this difference would be weaker for short‐lived organisms. We further predicted that short‐lived organisms with rapid dispersal would reflect recent environmental change. In 51 plots of ombrotrophic summit bogs in two mountain ranges of Central Europe, we sampled the contemporary species composition of vascular plants, bryophytes, diatoms and testate amoebae. In the same plots, water chemistry (pH, conductivity, Ca, Mg, Na, K, Al, Fe, Pb, Hg, Zn, humic acids, ammonium, nitrates, nitrites, phosphates, sulphates and chlorides) and water level were monitored three times per year for 15 years. We tested species–environmental relationships using Mantel tests and canonical correspondence analyses with Monte Carlo permutation tests for overall, within‐bog and between‐bog effects. The species composition of all four taxa changed along a natural gradient of water level. Diatoms and testate amoebae also changed along a pH/calcium gradient, which has appeared recently in one of the study regions because of aerial liming of forests. Only diatoms reflected variations in humic acid concentration. Spot measurements of environmental factors were sufficient to describe the general pattern while significant effects of phosphates for diatoms and bryophytes, nitrites for vascular plants, potassium for vascular plants and testate amoebae, sodium for all groups except diatoms and sulphates for bryophytes and testate amoebae were evident only by using medium‐ or long‐term averages. Although only long‐term averages of some environmental variables were sufficient to explain species compositions, major patterns were revealed by single (spot) samples. The explanatory power of long‐ and short‐term environmental conditions did not differ substantially between micro‐ and macroorganisms, although short‐lived and well‐dispersed microorganisms reflected the new pH/calcium gradient.

Restoration potential of native forests after removal of Picea abies plantations

Coniferous plantations may reduce biodiversity and homogenise environmental conditions but there is a lack of knowledge on the restoration potential of such sites. We assess whether first generation plantation impacts on soil and biodiversity are reversible. The study was carried out in western Norway and we compared species composition, alpha and beta diversity of vascular plants and bryophytes, and soil conditions on five sites of 4-year old wind-felled clearings and adjacent, remnant Norway spruce (Picea abies) plantations. Local native birch (Betula pubescens) forests provided a reference point for assessing the restoration potential of the Norway spruce plantations. We found that species composition in the wind-felled clearings quickly developed similarities to the local birch forests. A rise in humus pH, calcium concentrations and available nitrogen (total N in percentage of loss on ignition), indicates that one rotation of Norway spruce plantations has not imposed long-term impairment of soil conditions. After removal of the plantation tree layer, mean species number per plot (alpha diversity) increased for vascular plants but remained unchanged for bryophytes. Heterogeneity, in terms of beta diversity, and the variance of some soil elements (calcium and magnesium) increased, and beta diversity trends were similar for both vascular plants and bryophytes. During the course of succession, we predict that species composition and vascular plant alpha and beta diversity in wind-felled clearings of Norway spruce plantations may stabilise at levels similar to native birch forests.

Shedding new light on the diet of Norwegian lemmings: DNA metabarcoding of stomach content

Lemmings are key herbivores in many arctic food webs, and their population dynamics have major impacts on the functioning of tundra systems. However, current knowledge of lemming diet is limited, hampering evaluation of lemming–vegetation interactions. This lack of knowledge is mainly due to methodological challenges, as previously used microhistological methods result in large proportions of poorly resolved plant taxa. We analyzed diets of Norwegian lemmings (Lemmus lemmus) in three different habitats using a new method, DNA metabarcoding of stomach contents. To achieve detailed information on ingested vascular plants, bryophytes, and fungi, we amplified short fragments of chloroplast DNA (for plants; P6 loop of the trnL intron) and nuclear ribosomal DNA (for fungi; ITS1-region). Our results revealed that lemming diets were dominated by grasses, mainly Avenella flexuosa, and mosses, mainly Dicranum spp., but that a variety of other food items were also eaten. Vascular plant composition of the diets differed between heath, meadow, and wetland habitats, whereas bryophyte composition did not. Also, a variety of fungal taxa were retrieved, but as most of the identified taxa belong to micromycetes, they were unlikely to be consumed as food. The role of fungi in the diet of lemmings remains to be investigated. We suggest that there may be substantial variation between habitats and regions in lemming diet.

Bryophyte communities along horizontal and vertical gradients in a human-modified Atlantic Forest remnant

We compared the richness, diversity, and composition of epiphytic bryophytes in a Brazilian Atlantic Forest remnant along zones of height within host trees (vertical gradient) and edge to interior (horizontal gradient). We established five classes of edge distance, and within each one, three host trees were selected (15 in total). Samples were collected in five height zones within host trees from the base to the top. The highest average values of richness and diversity were found in the trunk zone. There was no significant difference of bryophyte total richness and diversity along edge distance and vertical zones. However, the guilds of light tolerance displayed particularities regarding vertical zonation. Shade epiphytes decreased significantly along vertical gradients, whereas sun epiphytes increased, demonstrating a compositional vertical stratification within host trees. Thus, bryophyte distribution in both understories and canopies is more related to microenvironmental conditions than landscape characteristics such as edge distance. Moreover, the features of the Atlantic Forest associated with the environmental heterogeneity of the remnant may play an important role in the lack of gradient in species' composition from the edge to the interior of the forest.

Bryophyte assemblage structure after partial harvesting in boreal mixedwood forest depends on residual canopy abundance and composition

Forest harvesting practices designed to conserve biodiversity require further insight into the relationship between species habitat requirements and how these are preserved after harvest. We examined the effects of different levels (10%, 50%, and 75%) of dispersed green-tree retention (unharvested stands as controls) on the diversity and composition of bryophytes 5–6years after partial harvesting. Bryophytes were sampled in six large (20m radius) plots in 24 forest stands (each 10ha) using a factorial experimental design with replication at the stand level. Sampled stands represented two mixedwood forest canopy types with contrasting abundances of broadleaf and coniferous trees before harvesting. Mosses and liverworts both responded to retention level and forest type but liverwort response was more pronounced. Liverwort richness and diversity were reduced at low (10% and 50%) retention, and composition differed between all harvested levels and the control. In comparison, mosses did not differ in richness or diversity among retention levels but at low retention composition differed from that of intact forest. Bryophyte responses to harvesting were partly explained by species substrate preferences: epixylics on decayed wood and epiphytes on bark experienced declines in richness with any level of harvesting, whereas responses for species on other substrates were not as apparent. Furthermore, partial harvesting influenced regional patterns of species diversity, as revealed by additive partitioning of diversity into within-plot (alpha) and among-plot and among-stand (beta) components. For both mosses and liverworts, total beta diversity explained the greatest proportion of total diversity for each retention level, indicating that species representation in boreal mixedwood landscapes after harvesting needs to be considered at multiple hierarchical levels. Total beta diversity of liverworts but not mosses increased substantially at low retention, reflecting greater among-plot and among-stand differentiation of liverwort assemblages with increasing disturbance. Results highlight the importance of canopy retention and composition for maintaining bryophytes in managed forests. Although several species persisted at low retention, intact forest is required for the conservation of numerous species that are sensitive to any degree of harvest. Implementation of conservation strategies for bryophytes in managed boreal forests should consider species diversity not only at local scales but also differences among entire forest stands.

Impact of land-use intensity and productivity on bryophyte diversity in agricultural grasslands.

While bryophytes greatly contribute to plant diversity of semi-natural grasslands, little is known about the relationships between land-use intensity, productivity, and bryophyte diversity in these habitats. We recorded vascular plant and bryophyte vegetation in 85 agricultural used grasslands in two regions in northern and central Germany and gathered information on land-use intensity. To assess grassland productivity, we harvested aboveground vascular plant biomass and analyzed nutrient concentrations of N, P, K, Ca and Mg. Further we calculated mean Ellenberg indicator values of vascular plant vegetation. We tested for effects of land-use intensity and productivity on total bryophyte species richness and on the species richness of acrocarpous (small & erect) and pleurocarpous (creeping, including liverworts) growth forms separately. Bryophyte species were found in almost all studied grasslands, but species richness differed considerably between study regions in northern Germany (2.8 species per 16 m2) and central Germany (6.4 species per 16 m2) due environmental differences as well as land-use history. Increased fertilizer application, coinciding with high mowing frequency, reduced bryophyte species richness significantly. Accordingly, productivity estimates such as plant biomass and nitrogen concentration were strongly negatively related to bryophyte species richness, although productivity decreased only pleurocarpous species. Ellenberg indicator values for nutrients proved to be useful indicators of species richness and productivity. In conclusion, bryophyte composition was strongly dependent on productivity, with smaller bryophytes that were likely negatively affected by greater competition for light. Intensive land-use, however, can also indirectly decrease bryophyte species richness by promoting grassland productivity. Thus, increasing productivity is likely to cause a loss of bryophyte species and a decrease in species diversity.