Aims Most of the grasslands in the Sanjiangyuan area are degraded to varying degrees, and planting artificial grassland is an important measure to restore the ecological function of severely degraded grasslands. Moss crust affects soil nutrient cycling and the structure of microbial communities, so it is critical to investigate the feasibility of using moss crust to promote the restoration of degraded grasslands to understand the ecological role of bioconjugate crusts and develop reasonable and effective ecological restoration measures.

Methods In this study, four different grass combinations and three types of moss crust inoculation were set up to investigate the effects of moss crust inoculation on the soil microenvironment of artificial grassland in the “black soil beach” of Sanjiangyuan.

Important findings Moss crusts increased soil organic carbon, available phosphorus, ammonium nitrogen contents, and nitrate nitrogen contents, and available nutrients content were significantly higher in the artificial grassland than in the “black soil beach”. Actinobacteria, Proteobacteria, Acidobacteriota, Chloroflex, and Firmicutes were the top 5 dominant taxa in terms of mean relative abundance at the phylum level for bacteria, while Ascomycota, Basidiomycota, Mortierellomycota, unclassied_k_Fungi, and Olpidiomycota were the top 5 dominant taxa in terms of mean relative abundance at the phylum level for fungi. With the increase of moss crust inoculation, the number of bacterial operational taxonomic unit (OTUs) decreased and the number of fungal OTUs increased, and the moss crust inoculation did not significantly affect the microbial diversity index. The mixed-effects model results indicated that the moss crust significantly had a significant effect on the effective phosphorus, nitrate nitrogen, ammonium nitrogen contents, and microorganisms affecting their accumulation. Redundancy analysis shows that the bacterial community structure is susceptible to soil factors. Mantel test results showed that moss crust A1 (700 g·m^-2) inoculation had a significant effect on bacterial community composition than fungal community. Additionally, effective phosphorus, ammonium nitrogen, and nitrate nitrogen contents were positively correlated with the bacterial community. The above findings suggest that moss crust inoculation may affect soil nutrient accumulation and cycling by altering the microbial community environment, as well as promote the recovery of ecological function of the artificial grassland in Sanjiangyuan, providing a theoretical basis for future research into moss crust addition to restore the ecological function of soil in extremely degraded grassland.

Aims The species-area relationship describes a fundamental pattern in community ecology, illustrating how species richness changes as the sampled area increases. It is a core issue in community ecology research. The island biogeography theory highlights a specific aspect of the species-area relationship known as the small island effect (SIE), which is a key component of the theoretical framework of island biogeography and biodiversity studies. Coastal islands represent a tangible and existing island system, yet there is relatively limited research on the SIE, especially concerning bryophytes.

Methods This study investigated the species composition of bryophytes on 43 coastal islands in the Xiangshan region of Zhejiang. We utilized four segmented regression models and two control models to examine the SIE across different bryophyte taxa. We compared the thresholds at which it occurs. Using generalized linear mixed-effect models and Mantel tests, we explored the impact of environmental factors, such as landscape characteristics and human disturbances, on bryophyte species richness on these maritime islands. Furthermore, we analyzed the response of different bryophyte taxa (liverworts, mosses, acrocarpous mosses, and pleurocarpous mosses) to environmental factors in these island environments.

Important findings Our study documented 209 bryophyte species belonging to 46 families and 85 genera across the 43 coastal islands in the Xiangshan region. All bryophytes taxa exhibited the SIE, with the double-breakpoint model identified as the optimal model. The area thresholds ranged from 0.098 to 4.419 km², with mosses showing higher thresholds than liverworts, and acrocarpous mosses higher than pleurocarpous mosses. Moreover, the richness of bryophytes increased with the island area, habitat richness, shape index, coastline length, population size, and traffic frequency, while it decreased with increasing isolation. Habitat richness was identified as the primary factor influencing bryophytes richness. Generally, taxa with lower resource requirements and higher dispersal abilities (such as mosses) exhibited lower SIE area thresholds. Larger islands with greater distances from the mainland, characterized by lower vegetation cover and habitat richness, were less suitable for the growth of pleurocarpous mosses, resulting in lower SIE area thresholds than acrocarpous mosses. Therefore, the conservation of habitat diversity is crucial for maintaining species diversity.

Aims Xizang is one of the most sensitive regions to global climate change, and bryophytes are sensitive indicator plants to environmental change. This study investigates the relationship between morphological traits and environmental factors such as climate, soil, and vegetation of Didymodon constrictus, which is widely distributed in Xizang. It analyzes the response strategies of bryophytes to environmental changes, providing reference for revealing the response mechanisms of bryophytes to environmental changes and formulating protection strategies for bryophytes in Xizang.

Methods Specimens were collected from Xizang from 2007 to 2015, and valid specimens of D. constrictus with a certain spatial distance were confirmed. Six mature plants were selected from each specimen and the morphological traits of plant height, leaves and related cells were measured. Pearson and redundancy analysis methods were used to analyze their relationships with the environmental conditions.

Important findings With the altitude increases, the plants become shorter, the leaves tend to be ovoid and the cell walls thicken. As the air temperature rises and precipitation is abundant, the plants become taller, the leaves are elongated, the midribs are short, and the cell wall are thinner. When solar radiation increases, the angle of leaf inclination on the stem decreases. The results also showed that the environmental factors that have a significant impact on the growth of D. constrictus, including annual mean air temperature, annual precipitation, and solar radiation. The response of plant height, area of leaf, and angle of leaf to environmental changes is relatively sensitive, while at the cellular level, area of leaf cell and cell wall thickness are preferred as measurement indicators. We consider that plant height, leaf area and leaf inclination are more sensitive to environmental changes, while leaf cell area and cell wall thickness are preferred as measures at the cellular level. In summary, the various morphological traits of moss plants are closely related and moss plants respond synergistically to environmental changes through combined changes.

Aims Sphagnum, as the dominant species in Sphagnum wetland, is the most important carbon (C) sequestration plant. The physiological and morphological characteristics of Sphagnum determine the carbon sink potential of Sphagnum wetland. Nitrogen (N) deposition has a significant effect on the physiological and morphological characteristics of Sphagnum,but the effects of N deposition on such characteristics of Sphagnum in the wetland environment remain controversial. Moreover, there are few reports on the physiological and morphological characteristics of Sphagnum in subtropical wetlands.

Methods We selected a Sphagnum wetland in southwestern Hubei Province as the study area. Different concentrations of NH₄Cl solution were sprayed in situto investigate the effects of simulated N deposition on physiological and morphological characteristics of Sphagnum. Four N concentrations were applied, namely 0 (N0), 3 (N3), 6 (N6) and 12 g·m^-2·a^-1 (N12), with N0 representing the control (CK).

Important findings (1) Nitrogen deposition had significant effects on the contents of total C and total N in Sphagnum. Among the treatments, the contents of total C and total N in Sphagnumunder the N3 treatment were the highest, and compared with those of the CK, increased by 3.78% and 88.52%, respectively. (2) Nitrogen deposition had no obvious effect on chlorophyll content and fluorescence activities of Sphagnum. However, N deposition significantly promoted the antioxidant enzyme activities and the contents of osmotic substances in Sphagnum,especially the contents of soluble sugars and peroxidase activity. (3) With the increase in N deposition, the height, branch number, mass per plant, and leaf cell area of Sphagnum tended to initially increase and thereafter decrease. The maximum values were observed in response to N deposition of 3 g·m^-2·a^-1. (4) Sphagnum was sensitive to N deposition, and there was a certain load value of the effect of N deposition on physiological and morphological characteristics of Sphagnumafter 2 years treatment, which was approximately 3 g·m^-2·a^-1. When the amount of N deposition is greater than 3 g·m^-2·a^-1, the effects on morphological indicators of Sphagnum are detrimental and the stress to Sphagnumwill increase significantly. The results of this study indicated that the current natural atmospheric N deposition is beneficial to the growth of Sphagnum in the wetland in southwestern Hubei Province. However, continual or doubled N deposition might be harmful to the growth of Sphagnum.

Aims As anisohydric plants lacking vascular tissue, mosses are thought to be influenced on their water movement and photosynthesis mainly by the water status and light of the ambient environment. Do the mosses develop an intrinsic circadian regulation mechanism similar to that of vascular plants as these environmental conditions change with day and night alteration? Understanding its rhythmic response characteristics is of great significance for the conservation and utilization of the mosses.

Methods The Brachythecium thraustum, Hypnum plumaeforme and Mnium lycopodioides were trained to 12 h/12 h light-dark (LD) cycles before transfer to 24 h/0 h constant light. We measured the three mosses’ net photosynthetic rate (P_n) and transpiration rate (T_r) on the constant light and last day of the light-dark cycles. Subsequently, non-structural carbon (NSC) content was measured for Brachythecium thraustum. Finally, we sequenced the Brachythecium thraustum transcriptomes in a time series in constant light conditions.

Important findings We found the significant rhythmic changes in the P_n and T_r of the three mosses when excluding environmental influences such as light and vapor pressure difference (VPD), and rhythmic regulation could explain 23.4% and 30.2% of the diurnal changes in P_n and T_r. Moreover, the rhythmic effect of T_r, which is rarely observed in vascular plants, appeared in all the mosses tested, and the rhythmic responses of P_n and T_r were different among species. The species with the strongest rhythm in this study was Brachythecium thraustum, and it was further analyzed for the rhythmic responses of time-series transcriptome and its NSC content under full light. The results showed that 35.1% of starch and carbohydrate biosynthesis-related genes showed rhythmic expression, which was closely related to NSC content change. In addition, the rhythmic regulation of T_r was associated with the transcript changes of abscisic acid signaling and stomatal regulation. Furthermore, the photosynthesis rhythms were associated with transcript changes of photosynthesis-related protein, like photosynthetic electron transport and carbon sequestration proteins. Although the CCA1/LHY genes, the core feedback loop of the circadian clock, have been lost in the mosses, the core circadian clock function concentrates in the PRRs family. The rhythmic response to carbon sequestration and water consumption is highly conserved.

Aims Ombrotrophic peatlands, dominated by Sphagnum, are important carbon sinks in terrestrial ecosystems. The dynamics of growth and decomposition of dominant plants usually determine the carbon sink potential of ombrotrophic peatland. However, it is still controversial how nitrogen deposition impact on the growth and decomposition of mosses in ombrotrophic peatland. Moreover, the effects of nitrogen deposition on the growth and decomposition of dominant mosses are rarely reported in subtropical ombrotrophic peatlands.
Methods We selected an ombrotrophic peatland in southwestern Hubei Province as the study area. Different concentrations of NH₄Cl solution were sprayed in situ. Here biomass harvesting and decomposition bag methods were adopted to estimate growth and litter decomposition of S. palustre and Polytrichum commune.
Important findings (1) Nitrogen deposition had obvious effects on the height and biomass of the two mosses. Moreover, there was a threshold value of nitrogen deposition at the level of about 3 g·m^-2·a^-1. (2) The effects of nitrogen deposition on the growth of the two mosses were different, and the response sensitivity of S. palustre to nitrogen deposition was greater than that of P. commune. (3) High nitrogen deposition levels (i.e., 6 and 12 g·m^-2·a^-1) inhibited the decomposition of S. palustre, while the effect of low nitrogen deposition (i.e., 3 g·m^-2·a^-1) on the decomposition of S. palustre depends on time. All the concentrations of nitrogen deposition inhibited the decomposition of P. commune litter. (4) After one year of decomposition, the average final mass residual percentage of S. palustre was 105.99%, and 70.79% for P. commune. The decomposition rate of P. commune was much higher than that of S. palustre. (5) Nitrogen deposition significantly affected the chemical element content and stoichiometric ratio of the two moss litters, and was closely related to decomposition time.

Aims As an anomalous feature of the species-area relationship (SAR), the small-island effect (SIE) is an important pattern in the fields of island biogeography and biodiversity science. However, the existing work has rarely explored the SIE in fragmented mountaintops. Moreover, the underlying factors determining the SIE remain largely untested. In this paper, we aimed to evaluate the prevalence and underlying factors determining the occurrence of SIEs in mosses on mountaintops of the Middle Taihang Mountains.
Methods We investigated and compiled data on the species richness of all mosses and six most common moss families on 19 mountaintops of the Middle Taihang Mountains. For each of the seven taxonomic groups, we applied six SAR models, including four piecewise regressions with two segments, a linear regression, and a zero-slope regression as a null model, to detect the SIE and then used the corrected Akaike’s information criterion (AICc) as a criterion to select the best model. We obtained three environmental variables, including island height, annual temperature range, and net primary productivity per unit area that are linked to the habitat diversity hypothesis, the extinction hypothesis, and the subsidized island biogeography hypothesis, respectively, in order to explore the underlying drivers of the SIE. We applied iterative multiple linear regression and variation partitioning to determine the effects of island area and each of environmental variables on species richness for islands of varying sizes. Finally, we analyzed the trends of environmental variables’ contributions to species richness variation over the iterative process by using generalized linear regressions with polynomials of area up to the second degree.
Important findings A total of 131 moss species, belonging to 23 genera under 68 families, were identified. SIEs were detected for all mosses and six most common moss families, with the area thresholds varing between 0.36 km² and 106.91 km². The driving factors of the SIE differentiate among groups. Among them, Grimmiaceae did not support the habitat diversity hypothesis; Pottiaceae, Bryaceae, Grimmiaceae, and Hypnaceae did not support the extinction hypothesis; whereas, the subsidized island biogeography hypothesis was generally supported by each group to varying degrees. On the whole, mountaintops with an area of ​​over 10 km² maintain a large diversity of moss species and thus be identified as site conservation targets. For mosses with relatively unique habitat requirement, such as Grimmiaceae, protecting the stony habitat is the key to maintain its species diversity; as for other mosses, conservation of habitat diversity is the key to maintain their species diversity. The general applicability of the subsidized island biogeography hypothesis suggests that the resource replenishment of the forest ecosystem below the mountaintops counteracts the removal of mosses’ species richness due to area reduction. Therefore, conservation of species diversity and community stability in the forest below the mountaintops is essential for sustaining moss species diversity in fragmented mountaintops.

Aims In order to explore the important ecological function of moss in forest ecosystems in the southeast Xizang and provide a theoretical basis for the influence of forest disturbance on forest surface vegetation, the diversity and biomass characteristics of ground moss per unit area in different habitats in the Sygera Mountain of southeast Xizang.

Methods We collected the surface moss in the Sygera Mountain of the southeast Xizang as the investigation object, and selected 7 sample plots with similar forest stand, slope direction, slope and terrain composition, with each plot size of 100 m × 100 m. We took canopy gap of each sample plot as the center, and three different habitats (canopy gap, forest edge and understory) were selected in four directions to set 50 cm × 50 cm quadrats, with 12 quadrats for each sample plot and 168 quadrats in total. Moss survey and collection were carried out in each quadrat.

Important findings (1) 24 families, 63 genera and 110 species of moss were found in the study area, in which there were 8 dominant families, which were Pottiaceae, Dicranaceae, Polytrichaceae, Mniaceae, Bryaceae, Grimmiaceae, Brachytheciaceae and Hypnaceae. There were obvious distribution rules of different moss families, such as Dicranaceae and Bryaceae were widely distributed at all elevations, and Polytrichaceae, Bryaceae and Mniaceae were distributed at altitudes from 3 700 to 4 300 m. Most of Pottiaceae were distributed over 4 300 m. (2) The habitat of canopy gap was more complex than those of forest edge and understory and it interfered with moss composition and community structure, in which the moss community had the most species and the most complex structure. However, the moss community in understory had the least species and the simplest structure. The biomass of ground moss was the highest in the gap, followed by the edge and the lowest in the understory. (3) The biomass of ground moss was not only affected by species composition, coverage, body shape and community structure, but also resulted from the interaction of many factors rather than any one single factor.

Aims Catalysis associated with extracellular enzymes are closely related to nutrient circulation and energetic flow in soils. Changes of global climate and land use have resulted in different degrees of death of moss-dominated biological soil crusts (BSCs), yet there is still little knowledge of how moss mortality influences the nutrient cycling in the topsoil of a temperate desert.
Methods In this study, we measured the enzyme activities related to carbon, nitrogen and phosphorus cycling in different soil layers (0-2, 2-5, 5-10, 10-20 cm) under living and dead mosses in a desert in Gurbantünggüt, Xinjiang, China.
Important findings We found that moss death had a significant effect on the activities of β-glucosidase, peroxidase, polyphenol oxidase, urease, nitrate reductase, phytase and alkaline phosphatase; these enzyme activities decreased with the increase of soil depth. The moss death decreased phytase activity, and increased enzyme activities related to carbon, nitrogen and phosphorus cycling. The results of correlation analyses showed that the carbon- and nitrogen-related enzyme activities were positively correlated with soil organic carbon, total nitrogen, NO₃^--N and NH₄⁺-N contents, and negatively correlated with pH, whereas the phytase and alkaline phosphatase activities had no significant correlation with total phosphorus and available phosphorus contents. In summary, the moss death in the temperate desert changed soil enzyme activities and accelerated soil nutrient cycling in a relatively short time.

Aims Wetlands are important sources of atmospheric methane (CH₄), but there are few reports on the CH₄ emissions of subtropical and subalpine wetlands. In particular, the accurate estimation of CH₄ emissions from plots with different types of plant cover and the controlling environmental factors are not clear. The objective of this study is to study characteristics and influencing factors of CH₄ emission fluxes from a Sphagnum bog with different plant cover types in a subalpine area, southwest of Hubei Province.
Methods A Sphagnum bog in the subalpine area in southwest of Hubei Province was selected, and CH₄emission fluxes were measured in the Sphagnum bog with three types of plant cover using closed static chamber and gas chromatography method from November 2018 to October 2019. Simultaneously, air temperature, soil temperature of 5 cm depth, and groundwater level were recorded.
Important findings (1) Under sunlight, the CH₄-C fluxes from the bare land plot (B), the Sphagnum paluster plot (S), and the Polytrichum commune plot (P) varied throughout the year within the following ranges: 0.012- 1.372, 0.022-1.474 and 0.027-3.385 mg·m^-2·h^-1, respectively; under shading treatment, the variation range of CH₄-C flux throughout the year from B, S and P plots were 0.012-1.372, 0.009-1.839 and 0.017-2.484 mg·m^-2·h^-1, respectively, indicating CH₄emission sources for all types. At the same time, for all plant cover types, CH₄ emissions under sunlight conditions were slightly higher than those under dark conditions, but the difference was not significant. (2) For all plant cover types, CH₄ emissions showed obvious seasonal variations, with the order of summer > autumn > spring > winter; and summer emissions were significantly greater than emissions in other seasons, accounting for about 57% to 84% of the annual cumulative flux. This study found that the flux of CH₄ emission was highly related to air temperature and soil temperature of 5 cm depth showing exponential relationships, which indicated that temperature is the main environment factor affecting the temporal variations of CH₄ emission from the Sphagnum bog. (3) Plant cover types significantly affected CH₄ emissions from theSphagnum bog. The annual average and cumulative CH₄ emissions from the three cover types were in the order of: P > S > B. P plot showed significantly higher emission than B plot. This study found a significant correlation between vegetation types and CH₄ emissions, indicating that plant cover type is the main influencing factor of the spatial variations of CH₄ emissions from the Sphagnum bog. (4) CH₄ emissions were not significantly related to the groundwater levels. This study further enriched the mechanisms of CH₄ emission in the Sphagnum bog and provided basic data for regional carbon cycling.

Aims Fallen logs play important roles in maintaining the health and the renewal of forest ecosystems, but the difference of bryophyte societies on fallen logs with different decay classes is unclear.
Methods To understand the regularity and influencing factors of changes in bryophyte societies, we investigated the bryophytes with quadrats along the trunks on four fallen logs of Pinus armandii with different decay classes at the same site in Sygera Mountains, Xizang. Then, the measured data were collected and analyzed.
Important findings There were 22 families and 52 species of bryophytes inhabiting the four fallen logs, including 13 families and 38 species of Musci, 9 families and 14 species of Hepaticae. According to the characteristics of the shared dominant species, 14 societies were obtained. With the increase of decay classes of fallen logs and changes in surrounding environment, the bryophyte diversity increased gradually, while the number of societies and the total bryophyte coverage fluctuated. Bryophyte species varied from drought-tolerant tall turfs, such as Orthotrichaceae and Leucobryaceae, to fast-growing cushions or mats in humid and shady environments, such as Mniaceae, Thuidiaceae and Brachytheciaceae. The complexity of spatial structure of bryophytic society increased gradually. Fallen logs are important growth substrates for a variety of bryophytes. Bryophyte societies on fallen logs vary with decay classes, moisture and light conditions.

Aims We investigated the growth and decomposition of Sphagnum, a principal plant involved in peat accumulation in wetlands, in subtropical wetlands.
Methods We selected a Sphagnum-dominated wetland in southwestern Hubei Province as the study area. In situ growth and litter decomposition experiments in different microhabitats were carried out, and the chemical composition of litter was measured in laboratory to examine the processes of its growth and decomposition.
Important findings The average height of Sphagnum in hummock and hollow were 2.9 and 2.7 cm, and the net production was 270.94 and 370.88 g·m ^-2, respectively, after 12 months. Growth time and microhabitats significantly affected on the height growth and the net production, and there was an interaction between time and microhabitats. However, the growth trend in two microhabitats was significantly different. The average growth rate of Sphagnum under the two microhabitats (July to October 2017) was 0.33 mm·d^-1, which was higher than that in the cold temperate zone. In addition, the decomposition time had an significant effect on the decomposition amount of Sphagnum, and the residual rate decreased first and then increased with time. By the end 12-month period, the final residual rates in hollow, hummock and pool were 100.67%, 90.54% and 85.63%, respectively. The content of carbon (C), carbon nitrogen (N) ratio (C:N) and polyphenols in the litters decreased, while the nitrogen content increased. During the first 3 months of decomposition, a significant difference of decomposed litter was found between the microhabitats, but no significant difference later on.

Bryophyte participate in karstification is an important part of biokarst process. Numerous studies on bryophyte karstification provide theoretical and technical foundation for restoration and comprehensive management of bare rock in the rocky desertification area. This article systematically reviewed the process (dissolution and sedimentation), mechanism and interaction relationship between bryophyte karstification and habitats. Bryophyte and its biological crusts emerge physical forces such as expansion, curling, freezing and thawing when they are under alternating wet or dry conditions can destroy rock. In addition, their metabolic secretions and H₂CO₃ formed by respiration, which react with minerals resulting in destruction of the crystal structure, pyrolysis the minerals, further the rock surface disintegrated and the surface morphology changed, the karst landform and the original soil formed. The driving force of bryophyte karstification closely related to plant functional traits, rock properties and habitat. Studies on biokarst need long-term monitoring and long research period. It is recommended to establish a long-term monitoring sites for strengthening examinations on process, internal mechanisms, and interaction relationship with habitat of bryophyte karstification. At the same time, physiological metabolic processes of bryophytes and the relationship with bryophyte karstification should be emphasized. The environmental adaptability of bryophyte and the maintenance mechanism of biodiversity in karst areas need research attention as well.

Aims To test the effects of environmental factors in peatlands on the persistence of Sphagnum spore germinability. The results may help to understand the mechanisms behind the formation of Sphagnum spore banks in peatlands. They can also provide valuable insights for restoration of degraded peatlands. Methods We determined the initial germination percentage in spores of two Sphagnum species (hummock- forming Sphagnum capillifolium and hollow-forming S. flexuosum) and then stored them for 60 days, either dry, in ultrapure water, peatland surface water or Sphagnum water leachate. We varied oxygen concentration by injecting air at three concentrations during the storage experiment. After retrieval from experimental storage, spore germinability was assessed. Important findings Spore germinability was lower after air-injection than under oxygen-deficiency. Spore germinability was higher after storage in the peatland surface and Sphagnum leachate water, having high concentrations of allelochemicals, than in ultrapure water, under oxygen-deficiency. Path analysis showed that dissolved oxygen is the main factor negatively affecting Sphagnum spore persistence in peatlands. Nitrogen (TN) and phosphorus (TP) also affect spore persistence negatively. These results indicate that once dispersed onto Sphagnum substrates or waterlogged hollows, Sphagnum spores can remain viable longer than when exposed to dry conditions or in water without allelochemicals. Extreme longevity of Sphagnum spores and other plant propagules may be attributed to the oxygen-deficient, nutrient-poor and allelopathic substrates in peatlands.

Bryophyte-cyanobacteria symbiosis (BCS) is a key source of nitrogen input into ecosystems in nutrient-poor regions. Investigating BCS relationships and the nitrogen fixation capacity can be a new pathway and window to explore the process and mechanism of nitrogen input and nitrogen cycling. However, BCS relationships and nitrogen fixation/cycling processes and mechanisms remain poorly studied, and most of these studies have only focused on the boreal forest, with no report from Chinese forests. Based on systematic literature search and analysis, this review provides a summary on BCS relationships, the nitrogen fixation capability of BCS, the fate of fixed nitrogen, as well as the environmental factors and driving mechanisms of BCS. Firstly, we synthesized different types of BCS, the mechanisms by which the fixed nitrogen is transferred to and used by other plants within the forest, the rate of fixed nitrogen, the factors influencing the rate of nitrogen fixation. Moreover we point out the existing problems that need to pay close attention to and at least four research directions need to break through. Furthermore, the theoretical basis of BCS is provided for further research, promote and deepen the cognition of BCS and nitrogen-fixing research.

Aims The desert moss Syntrichia caninervis is a dominant species in the moss biocrust of the Gurbantünggüt Desert. It plays an important role in soil stability and artificial biocrust reconstruction in desert ecosystems. Previous studies have demonstrated that although artificial cultivation techniques can promote the micropropagation of S. caninervis, the resulting moss performs poorly in maintenance ability. Water availability has been considered as a critical factor to stimulate the physiological activities in moss species. Our objective in this study was to determine the optimum water condition for growth of sand-cultivated shoots of S. caninervis in the process of transplanting cultured materials from laboratory to the field. Methods We used sand-cultivated S. caninervis grown from fragmented gametophyte leaves and stems above ground. The experiment was run for 30 days under conditions of three water treatments, including intermittent water supply (watering every three days), fully watered (watering every day), and drought (watering every six days) . Fluorescence and physiological indices of shoots, such as photochemical efficiency, pigment content, soluble sugar, free proline, soluble protein, catalase, peroxidase, superoxide dismutase activities and malondialdehyde were measured. Important findings The content of total chlorophyll, chlorophyll a and b in drought and fully watered treatments were significantly lower than in intermittent water supply treatment. Drought reduced the chlorophyll a/b ratio, and fully watered treatment deceased carotenoid content. Drought and fully watered treatments significantly reduced the maximal and actual photochemical efficiency and the soluble protein content, while increased most indices in osmotic adjustment substances and antioxidative enzyme activities, such as soluble sugar content, free proline content, catalase, peroxidase, superoxide dismutase and malonaldehyde content. Our results showed that the sand-cultivated S. caninervis accumulated osmotic adjustment substances and strengthened the antioxidative enzyme activities to survive under different water conditions, such as in the fully watered treatment. Compared with the intermittent water supply treatment, drought may lead to more damages in sand-cultivated shoots of S. caninervis, with the membrane lipid peroxidation being aggravated. Thus, intermittent water supply results in better development of artificial-cultivated S. caninervis than drought and fully watered treatments. This conclusion could provide theoretical basis for water saving management of artificially cultivated bryophyte in wild engraftment.

Aims Patchily distributed biological soil crusts and shrubs is one of the main vegetation cover types in Gurbantünggüt desert. The existence of shrubs in desert areas serves not only as a shelter for small animals, but also a good living condition for cryptogams and some herbs. Syntrichia caninervis, a dominant moss species in Gurbantünggüt desert, is patchily distributed under shrub canopy and open spaces between vascular plants. To our knowledge, the impacts of the removal of shrub canopy on physiological and biochemical characteristics of S. caninervis during the winter is still unknown.
Methods We simulated grazing of animals on Ephedra distachya at various rates (shrubs left intact, 50% shrubs removed, and shrubs removed completely) by cutting different percent of above-ground shoots of E. distachya. The shoot water content, chlorophyll fluorescence, proline content, soluble sugar content, soluble protein content, malonyldialdehyde (MDA) content, peroxidase (POD) and superoxide dismutase (SOD) activity were compared.
Important findings The results show that, as for proline and soluble sugar contents of tested S. caninervis, there were no significant differences among three treatments of shrub canopy. However, the MDA content, and the activities of POD, SOD, CAT were significantly higher than nature shrubs in snow cover periods. During snow-melting periods, soil moisture and temperature did not served as limiting factors on the growth of S. caninervis. The soluble sugar content, and the activities of POD, CAT with shrub removal were significantly higher than shrubs left intact. This may indicate that the decline of the function of maintaining constant soil temperature due to shrub canopy increased the damage of temperature on moss plants. In addition, as for physiological and biochemical characteristics, there were no significant differences between two treatments of 50% shrub canopy and shrub canopy left intact. In snow covered periods and snow melting periods, the MDA content, the activities of POD, SOD and CAT of S. caninervis under shrub canopy removed completely were significantly higher than that of 50% shrub canopy and shrub canopy left intact, except for soluble protein content. The duration of chlorophyll fluorescence activity of S. caninervis growing in habitats with shrubs removed completely was significantly shorter than that of S. caninervis growing in habitats of 50% shrub canopy and shrub canopy left intact. This result indicated that the removal of shrubs may increase the UV-B radiation and weaken the “moisture island effects” developed by the existence of shrub canopy.

The study area, Shapotou district (37°27′N, 104°57′E) of Ningxia Hui Autonomous Region is situated in the southeastern fringe of the Tengger Desert of China. A study of species identification, coverage and biomass in the soil microbiotic crusts of fixed sand dunes was conducted in Shapotou district, from which we found two families, seven genera and sixteen species of mosses. Didymodon constrictus (Mitt.) Saito and D. tectorum (C. Muell.) Saito were reduced to synonymy of D. vinealis (Brid.) Zand. by Zander and Redfearn. Crossidium chloronotos (Brid.) Limpr., Crossidium aberrans Holz. & Bartr. Aloina obliquifolia (C. Muell.) Broth. and Tortula atrovirens (Sm.) lindb. are new to Shapotou district. Bryum argenteum is an eurytopic species that survives on all kinds of habitat, and is the dominant component that forms moss synusia. The community of Didymodon vinealis, D. rigidulus Hedw. var. ditrichoides and Syntrichia bidentata are found on hillocks and are randomly distributed in crusts. Diversity of species is the highest in this area in the natural fixed dunes, with sixteen species, followed by five species of mosses (31.3%) in the fixed dunes of 1956, four species of mosses (25.0%) in the fixed dunes of 1964, and only two species of mosses (12.5%) in the fixed dunes of 1981. The total coverage of mosses and algae increased with the fixed-sand time. In different ages, the coverage of mosses and algae exist in an equal distance gradient, while in the fixed dunes they exist along the slope with the coverage of mosses decreasing as that of algae increased. A determination of biomass and binding-sand quantity of the dominant species—Bryum argenteum showed that its biomass (944.03 kg·hm-2) and binding-sand (3.925×104 kg·hm-2) quantity increased when the fixed sand time prolonged in moss crusts of the fixed dunes of 1950s. While the rate of binding-sand of Bryum argenteum decreased, its saturated water absorption had a positive correlation with biomass of 7.06×103 kg·hm-2. Therefore the results indicate that the moss crusts had a strong ability to absorb and reserve water, which is of ecological significance in arid desert region.

Bryophytes on the ground under six types of artificial forests, Picea balfouriana forest (P), Pinus tabulaeformis forest (Y), Pinus armandii forest (H), Larix kaempferi forest (L), Picea balfouriana-Pinus tabulaeformis forest (P-Y) and Pinus tabulaeformis-Pinus armandii forest (Y-H), were investigated in the upper Minjiang River in order to understand the bryophyte composition and synusia structure of these different forest types. In the 19 bryophyte species identified, only 13, 10, 7, 11, 9 and 10 species were present in the P, L, H, Y-H, Y and P-H forests, respectively. Four mosses, Brachythecium glaciale, Thuidium cymbifolium, Entodon concinnus and Eurhynchium savatieri, were common in all six plantations. Another three mosses, Entodon macropodus, Mnium spinosum and Polytrichum formosum, occurred only in the Picea balfouriana forest. The highest frequency of bryophyte occurrence was under the P forest (90%) and the lowest frequency under the H forest (17.65%). Thuidium cymbifolium had the highest frequency (60%) of all species under the P forest, and the second was Brachythecium glaciale (50%). The predominant species, based on the importance value, was Thuidium cymbifolium under the P forest and Brachythecium glaciale, occurred under the other five plantations, which indicated that Brachythecium glaciale was the most common moss species in the study area. In all forests, the P forest had the highest bryophyte diversity (Shannon-Wiener index, species richness index) and the H forest had the lowest diversity. The lowest Simpson index was calculated for the H forest and the highest one for the P forest. The highest similarity index (Sorensen similarity) occurred between the H and Y forests (0.89) and the lowest similarity index between the P and H forests (0.40). The greatest percent coverage (17.79%±1.67%), shoot density ((3 807.11±412.90) shoots•m-2) and thickness ((19.89±1.69) mm) of bryophytes occurred under the P forest, and the lowest values (0.41%±1.49%, (27.99±367.95) shoots•m-2, and (1.80±1.51) mm, respectively) under the H forest. For the Y, L, Y-H and P-H forests, ground bryophyte cover was 5.20%±1.58%, 2.44%±1.58%. 2.73%±1.61%, and 2.71%±1.61%, respectively, shoot density was (623.08±391.71), (566.13±391.71), (253.38±398.41), and (188.69±398.41) shoots•m-2, respectively, and average bryophyte thickness was (9.60±1.61), (14.93±1.61), (9.59±1.63), and (6.69±1.63) mm, respectively. No statistical differences (p<0.05) were found in any of these measures among the Y, L, Y-H and P-H forests. The low bryophyte diversity and limited structure development (density, coverage, thickness) found under all six plantations indicate that, in general, these are poorly developed bryophyte communities. Our results show that the best bryophyte community have developed under the spruce forest with a relatively open canopy and low tree density. Our results suggest that tree thinning or canopy pruning would be an effective measure for improving bryophyte development under dense forests.

Our objective was to analyze the effect of water levels and light intensities on capsule production dynamics of Sphagnum to lay the foundation for further research on its reproductive phenology.

Our selected Sphagnum capillifolium in this study. We set up a simulation experiment within a growth chamber and grew moss communities in polystyrene containers. Water levels and light intensities were altered to create different environmental conditions. Gametophores and capsule production were observed and recorded.

Seta length, shoot height and capsule cracking rate increased when water level increased. Under high light intensities, capsule diameter and capsule cracking rate were higher. Water level and light intensity had an interactive effect on shoot height increment and capsule diameter. Water level and light intensity had no effect on capsule production rate. Increase in both water level and light intensity led to earlier spore release. Reproductive phenology advance can reduce the abortive risk of spores by avoiding detrimental environment conditions such as drought. After capsules dehisced, reproductive shoots were able to accelerate height growth to avoid shading to lay a foundation for further reproduction in the future.

Syntrichia caninervis, a typical drought-tolerant moss species found worldwide in various semiarid and arid regions, is the dominant species of soil crust mosses in the Gurbantünggüt Desert, which is a temperate northern desert of Central Asia. It appears able to endure frequent and intensive freeze-thaw cycles in the surface soil and maintain physiological functions active even under extreme low temperatures in winter. However, there have been few studies exploring the adaptive strategies of the species during freeze-thaw processes and interpreting well the phenomena. One of the major goals of this study was to investigate physiological regulatory mechanisms of the species when undergoing freezing-thawing periods and relevant antioxidant enzyme activities.

A series of microclimate and soil conditions were continuously monitored in the sampling sites starting from November 2013. The samples of the moss were collected during the early spring of 2014 from February to April and from three microhabitats including the sites under live shrub, under dead shrub and on an open ground. The moss samples were quickly treated in the field for keeping freshness and then brought to laboratory for measurement and analysis. The traits/characteristics that reflect physiological and biochemical activities were measured for analyzing responses of the species to freeze-thaw processes and for comparing the impacts of different habitats, which included water content, concentrations of proline, soluble sugar, soluble protein and malondialdehyde (MDA), as well as catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) activities.

The results showed that, during different freeze-thaw periods, microhabitats and their interactions with alternative freeze-thaw processes significantly affect the contents of proline, soluble sugar, soluble protein and MDA in shoots of the species, as well as the enzyme activities of CAT, POD, and SOD. Extreme low temperature and drought caused significantly higher soluble sugar and MDA contents, higher CAT, POD and SOD activities, but lower soluble protein content, in snow covered period (February) and dry period (April) than the snow melting period (March). The existence of live shrub decreased temperature around the bushes during snow melting because of the effect of shade, causing increased contents of soluble sugar and MDA in moss shoots, when compared to those growing in the habitats under dead shrub and on open ground. However, live shrub could provide a moister environment for S. caninervis than dead shrub and exposed ground for the duration of desiccation. As the result, the proline content, soluble sugar content and MDA content of the species under the live shrub canopy were the lowest among the three habitats. Furthermore, the mosses lived on the exposed ground showed the highest antioxidant enzyme activities comparing to those under the dead shrub and living shrub. This may suggest that S. caninervis grown on exposed grounds has developed rather a specific adaptations for a harsher environment condition than that occurred in other two habitats.

The objective of this study was to investigate the tolerance of Polytrichum commune to soil contamination by polychlorinated biphenyls (PCBs), and the underlying eco-physiological mechanisms.

Polytrichum commune was propagated and cultured in PCBs contaminated soil by means of micropropagation under laboratory conditions, and eco-physiological variables relating to tolerance to PCBs (Aroclor 1242 and Aroclor 1254) contamination were studied.

The coverage and density of P. commune were higher than 93% and 50 plants·cm^-2 and there was no significant difference between the PCBs treatments and the control. PCBs (Aroclor 1242 and Aroclor 1254) had no adverse effects on the regeneration of gametophyte fragments. The height and fresh mass of P. commune increased with an increase in the concentration of Aroclor 1242, and decreased with an increase in the concentration of Aroclor1254, but they were higher in the PCBs treatment than in the control, indicating that PCBs stimulated the growth of P. commune. The contents of chlorophyll (Chl) a, Chl b and Chl a + b in P. commune were slight higher in the PCBs treatments than in the control, and the ratio of Chl a/b maintained relatively stable in both the PCBs treatments and the control. The content of malondialdehyde and activity of superoxide dismutase in P. commune were not significantly different between the PCBs treatments and the control, whereas the content of glutathione was significantly higher in the PCBs treatments than in the control, indicating that glutathione played a pivotal role in the course of scavenging reactive oxygen species. The study demonstrated that the growth of P. commune was not adversely impacted by PCBs contaminated soil at given concentrations, reflecting its tolerance to PCBs.

Aims Water is the most constraining factor to the growth of plants in arid and semiarid regions of China. Biological soil crusts (BSCs) develop well in Gurbantünggüt Desert and Syntrichia caninervis is a dominant species in the moss crusts of this cold desert. Compared to other desert ecosystems, the Gurbantünggüt desert is home to stable and abundant snow cover in winter. The moisturizing and warming effects of snow cover provide the desert mosses with optimal growth conditions. Our objective in this study was to determine how S. caninervis shoots utilize the special snow resources under different microhabitats in early winter.
Methods The experiments were conducted from prior to the snowfall and until following the snow thawing at a long-term study site of the Gurbantünggüt Desert. We measured the physiological and biochemical characteristics in S. caninervis in three habitats: the live shrub, the dead shrub, an exposed area. The shoot water content, chlorophyll fluorescence, proline content, soluble sugar content, soluble protein content, malonyldialdehyde (MDA) content, peroxidase (POD) and superoxide dismutase (SOD) activity were compared.
Important findings The results showed that snowfall increased moss water content, the maximal photochemical efficiency of PSII (F_v/F_m), soluble sugar content, SOD and POD activity. The content of proline and MDA were reduced with snow melting. Microhabitats influenced the physiological characteristics in S. caninervis, with the effects varying with snowfall event. The water content and chlorophyll fluorescence activity were significantly higher in samples under the living shrub, while in the exposed area S. caninervis had lower water content and chlorophyll fluorescence activity regardless of the snowfall cover. These findings suggested that the S. caninervis plants under the loving shrub experienced the least stress and had the best physiological performance but weak resistance, and that those in exposed area were more stress tolerant and had poorer physiological performance. Following the snowfall, proline content, MDA content, POD and SOD activity all had significantly negative correlations with plant water content; whereas the soluble sugar and protein content displayed significantly positive correlations with plant water content. The results indicated that snowfall reduced the water stress in S. caninervis, and enhanced their physiological performance and photosynthesis, with the effects being facilitated by the low temperature of the early winter.

Aims Bryophytes are an important component of forest vegetation. Their species diversity is vital to protecting plant resources and ecosystem diversity. Our objective was to explore the diversity and distribution of bryophytes and the relationship between bryophyte diversity and environment factors in seven dominant forest vegetation types (deciduous broad-leaved shrubs, DBS; deciduous broad-leaved forest, DBF; evergreen and deciduous broad-leaved mixed forest, EDF; evergreen broad-leaved forest, EBF; coniferous broad-leaved mixed forest, CBF; coniferous forest, CF; bamboo forest, BF) of West Tianmu Mountain, Zhejiang Province, China.
Methods Thirty-two sites (10 m × 10 m) were established in the seven forest vegetation types. Sixteen plots were selected by systematic sampling in each sampling site. Coverage of floor bryophytes and abundance of epiphytic bryophytes of each site were recorded. Species richness, importance value, diversity index and Sørensen’s similarity index were examined at the different vegetation types.
Important findings Based on collection and identification of a total of 969 specimens, we recorded 142 bryophytes belonging to 82 genera and 41 families, among which were 33 liverworts belonging to 18 genera of 33 families and 109 mosses belonging to 66 genera of 28 families. Hypanceae, Brachytheciaceae and Thuidiaceae were three dominant families. The species richness and diversity of bryophytes in two kinds of mixed forest types (EDF and CBF) were higher than the five pure forest types (DBS, DBF, EBF, CF and BF). EDF had the highest species diversity and CBF had the highest species richness. BF was lowest in both diversity and richness. There was high similarity between environment factors such as neighboring altitudinal forest types, with the highest value between EBF and CF, and the lowest value between DBS and BF. The number of microhabitats showed significant positive correlation with floor bryophyte diversity.

Aims Increasing N deposition and frequent abnormal weather are two characteristics of global climate change. Our objective was to study the physiological responses of bryophytes to simulated nitrogen treatments and low temperature stress to provide insights to the relationship between N deposition and compensatory effect after low temperature stress.
Methods Physiological responses of three bryophyte species, Pogonatum cirratum subsp. fuscatum, Hypnum plumaeforme and Reboulia hemisphaerica, which were subjected to a 2-year-simulated N deposition and suffered a low temperature stress in early 2008, were studied and compared with the results of the bryophytes that experienced a 1-year-simulated N deposition and normal weather conditions. N treatments (Control, 20, 40 and 60 kg N·hm^-2·a^-1) in three replicates were established for each species. The N additions were divided into four applications per year.
Important findings The results of 2008 showed that net photosynthetic rate and concentration of starch decreased with increasing N addition doses within the range of 0-60 kg N·hm^-2·a^-1. The concentration of total N increased with increasing N treatment doses within the range of 0-40 kg N·hm^-2·a^-1, but decreased at N addition doses of 60 kg N·hm^-2·a^-1. At control and low N addition conditions (20 kg N·hm^-2·a^-1), most of the indices of carbon and nitrogen metabolism of the three bryophytes were higher than the results of 2007 of the same species at the same N treatments, but N addition depressed the increase. At high N treatment conditions (≥ 40 kg N·hm^-2·a^-1), the results of 2007 and 2008 were usually similar. Results indicate that the bryophytes exhibit overcompensatory growth after experiencing a low temperature stress, but at stimulated N deposition conditions, their compensatory ability decreases.

Aims Increasing global N deposition will lead to severe damage to bryophytes due to their sensitivity to N deposition. Our objective is to examine the responses of three species of bryophytes, widely distributed in South China, to simulated N deposition.
Methods Four N addition treatments (Control, 20, 40 and 60 kg N·hm^-2) in three replicates were established for Reboulia hemisphaerica, Hypnum plumaeforme, and Pogonatum cirratum subsp. fuscatum. The N additions were divided into four applications.
Important findings With N addition treatments in the range of 0-60 kg N·hm ^-2 for H. plumaeforme, photosynthesis, concentrations of starch, soluble sugars, total N and soluble proteins all increased with increasing N addition. Inducible nitrate reductase activity (NRA) of H. plumaeforme at control conditions was very high, indicating its N-limited situation. K ⁺ leakage of H. plumaeforme increased at 20 kg N·hm ^-2 treatment, but did not further increase at higher N addition concentrations. Most of the physiological indices of P. cirratum subsp. fuscatum showed similar trends within an N treatment of 0-40 kg N·hm ^-2, but showed opposite trends at >40 kg N·hm ^-2. Inducible NRA of P. cirratum subsp. fuscatum at the control condition was 2.20 µg N·g ^-1 FW·h^-1, but decreased dramatically when treated with N. Its K⁺ leakage only increased significantly at the 60 kg N·hm^-2 N addition treatment. Soluble sugars and soluble proteins of R. hemisphaerica were not significantly different at different N treatments, but photosynthesis and the starch concentration were lower at 20 and 40 kg N·hm ^-2treatments than at control and 60 kg N·hm^-2 treatments, while the total N concentration changed inversely. The inducible and constituted NRA of R. hemisphaerica were both very low for all treatments, indicating its restricted ability to utilize nitrates. K ⁺ leakage of R. hemisphaerica increased significantly only at an N addition of 60 kg N·hm ^-2.

Aims Traditional forestry management influences biodiversity. Revealing effects of clear-cutting and silvicultural history on ground bryophyte communities is important for evaluating impacts of forest management on biodiversity.

Methods We selected four sites with similar physical conditions but different development phases in Rangtang County. We investigated bryophyte and vascular plant vegetation, including species composition and structural characteristics, in 30 plots in each site. ANOVA analysis was used to detect differences among bryophyte communities, and the relationship between vascular plant and bryophyte communities was examined by partial correlations.

Important findings Bryophyte composition changed significantly during developmental processes of young forests. Photophilic or pleurocarpous mosses were dominant species, while some hygrophilous mosses expanded their populations and become dominant species locally and drought-tolerant species occurred because of disturbance. Richness index (22-37) and diversity index (0.37-1.08) increased during the process of development, and the four young forestlands had differences in structural characteristics. There was a positive relationship between cover of tree and shrub layers and development of bryophytes. Shrub layer significantly promoted bryophyte richness, while pioneer grass with strong development and litter restrained bryophyte development. Characteristics of development in tree, shrub, litter layer and their interaction changed dynamically during the developmental process. Promoting development of tree and shrub layers has an important role on enhancing bryophytes.

Aims We investigated the new and senescent tissues of moss and the soil rhizosphere to determine 1) the elemental and isotopic composition characteristics during senescence and 2) the final contribution to soil.

Methods C and N contents and isotopic composition (δ¹³C and δ¹⁵N) of Haplocladium microphyllum and its soil rhizosphere were analyzed at Guiyang, China.

Important findings The C and N contents were higher in new growing tissues than in senescent tissues, and there were significant correlations between the two types of tissues, indicating physiological malfunction (e.g., loss of photosynthesis) and internal element redistribution during moss senescence. No significant difference was found between new and senescent tissues in isotopic composition, but their δ¹³C values or δ¹⁵N values were correlated, suggesting special isotopic regulation in the simple and nonvascular structure of mosses. In contrast, there was no C or N correlation between the moss tissues and soil. This was attributed to long-term nutrient retention and slow deposition to form soil, indicating the moss layer in this area has a small contribution to soil carbon and nitrogen.

Aims Mosses constitute major ground cover of the subalpine forests in the eastern Tibetan Plateau. Moss leaves have one layer of cells and are highly sensitive to environment changes. This attribute of mosses can be used to monitor environment conditions and guide restoration. However, moss growth and especially variables affecting moss growth in subalpine forest ecosystems are poorly known. Even worldwide, the growth rate of mosses has been rarely studied because of time-consuming, inaccurate measuring methods.
Methods Two plots, one in old-growth spruce forest and the other in nearby clear-cut land in subalpine western Sichuan, were selected. We labeled and measured mosses on May 7, 2001 and remeasured on August 7, 2001 and simultaneously recorded microclimate measurements.
Important findings The growth rate of mosses varied among species and habitats. Hylocomium splendens had the highest growth rate, while Dicranum assamicum had the lowest. The growth of H. splendens, D. assamicum, and Thuidium lepidoziaceum was faster in forest than in clear-cut land, where it was inversely correlated with distance to forest. Actinothuidium hookeri and Rhytidiadelphus triquetrus had moderate growth rates nearly independent of habitat. From May to July, the forest almost always had lower radiation level and vapor pressure deficit (VPD) favorable for moss growth. For habitat-insensitive species, microtopographic factors might have offset the effect of habitat. Moss growth rate and habitat VPD were strongly negatively correlated. Moss growth rate can be used to suggest favorable habitat.

Background and Aims The species diversity of bryophytes in Qinling was rarely studied, especially at different vegetation types. The bryophytes on floor were investigation in Foping Nature Reserve which lies in at the south slope of Qinling. Answers to the following questions were sought. a) What is the composition of bryophytes on floor in Foping Nature Reserve? b) What were the dominant families of bryophytes at there? c) How is the species diversity of bryophytes in Foping Nature Reserve?

Methods A investigation of bryophytes on floor were done in Foping Nature Reserve. The 29 sites were chosen in representative place, and the plots were setted with systematic sampling. The species similarity coefficient, important value and species diversity indexes were examined at different vegetation types.

Key Results A total of 189 floor species belonging to 69 genera of 33 families were founded. Among these species, there are 15 hepatics belonging to 8 genera of 7 families and 174 mosses belonging to 61 genera of 26 families, and Brachytheciaceae is the most dominant family. The species diversity of floor bryophytes is the highest one in deciduous oak forest zone, and it reduced in deciduous birch forest zone, bamboo forest, coniferous forest, rocks in valley, and it is the lowest in Rhododendron shrubs. The similarities between deciduous oak forest zone and deciduous birch forest zone are highest, and the similarities between Rhododendron shrubs and other vegetation types are lowest.

Conclusions It is shown that deciduous oak forest zone is the center of bryophyte diversity and the key area for bryophyte diversity conservation. Rhododendron shrubs have different species from other areas, so it should be paid attention in Foping Nature Reserve at the southern Qinling Mountain.

Soil microbiotic crusts cover extensive portions of the arid and semiarid regions of the world. Moss is one of the major components of the crusts. The reproduction and establishment of the mosses are crucial to the formation of moss crusts. Although many laboratory experiments have indicated that mosses can reproduce through spores, gemmae and fragmentation, the process of the dispersal and reproduction in natural conditions is not well understood in moss crusts. Bryum argenteum is the dominant species of moss crusts in the Shapotou region (37°27′ N, 104°57′ E) of the Tengger Desert. To examine characteristics of natural reproduction and establishment, 10 quadrats (10 cm×10 cm) were established on different positions of fixed dunes and the moss crust removed. These 10 quadrats were observed for three consecutive years and the species establishment and their coverage measured. In the third year, 2 quadrats (1 m×1 m) were established in a crust-absent area, and two different experiments were conducted, one on broadcast planting and the other on offshoots. The reproductive process was observed under the microscope, and the morphological indicators of new individuals measured. The results were compared with results from indoor experiments using the same methods. Our results showed that 70% of the quadrats (i.e., 7 of the 10 quadrats) recovered within 3-4 years. The quick recovery was most likely due to dispersal and reproduction of leaf and stem fragments of B. argenteum. Results from the artificial reproduction experiment showed that new plants occupied the uncovered space of the quadrats within one month. There were two main forms of reproduction: 1) stems continually branched and produced young plants; 2) young plants and the fragments of the stems and leaves repeatedly and extensively reproduced protonema which developed into a large number of new plants. The reproductive characteristics were identical between the two experiments although the protonema in the field was more robust and had more branches than the ones indoors. This research reveals the reproductive mechanism of the establishment of mosses in natural conditions in this region, and provides experimental evidence for the formation of moss crusts on fixed dunes.

Quantitative classification(TWINSPAN) and ordination (DCA) methods were used to study the distribution patterns of 60 species of bryophytes occurring in 60 sites in Bogda Mountain, Xinjiang. TWINSPAN results showed that the bryophyte communities of Bogda

DCA and TWINSPAN were applied in this study of the community distribution patterns of epiphytic bryophytes based on the cover of epiphytic bryophytes in different forests in Changbai Mountain. The results showed that the distribution of epiphytic bryophytes is well correlated with forest types. Epiphytic bryophyte communities in this area can be divided into six groups, which are distributed in Larix olgensis forest, Betula ermanii forest, dark conifer forest, transition forests between Pinus koraiensis broad-leaved mixed forest and conifer forest, Betula platyphylla forest and Pinus koraiensis broad-leaved mixed forest respectively. The factors influencing the ecological distribution of epiphytic bryophytes in Changbai Mountain were also analyzed and described.

This paper is report on the investigation of thirty sample plots in Fanjinshan’s bryophytes and elfin torest The results are as follows: 1. According to the distribution altitude, floristic composition the ratio of quantity to importance vuale between evergreen and deciduous trees and the life form spectrum, Fanjinshan’s elfin forest is regarded as a form of mixed forest of evergreen and deciduous trees. It is an orographic climax community. 2. Its special features are shown as: dwarfism with lower branches and no obvious trunk, bended shoots, close and level crown, slow growth, more mosses in its woods, floristic poverty, simple structure of layers and liana is rare. 3. The method of polar ordination is used to classify the coppice into six types: Rhododendron, Acer community, Prunus, Symplocos community, Acer community, Cyclobalanopsis stewardiana community, Sorbus, Rhododendron community and Buxus sinica community. 4.As the coppice has the character that germinative regeneration occupies an important place and the seed regeneration ability is weak, but the two modes of regeneration mutually complement to guarantee its regeneration, so it still is a stable community. 5. The basis of management is earnest protection for the Fanjinshan′s coppice.