An introduction to the family Bruchiaceae (Bryopsida in Australia is provided for the two genera Bruchia Schwaegr. and Trematodon Michaux together with a detailed revision, key to the species, illustrations and distribution maps for the five species of Trematodon now recognised in Australia. Of the nine species previously recorded for Australia, one species, T. amoenus (Müll. Hal.) Stone & Scott is endemic while T. flexipes Mitt. in Hook f. & Wilson, T. mackayi (R.Br. ter.) Broth. and T. suberectus Mitt., occur in Australia and New Zealand. Three species previously considered Australian endemics, T. baileyi Broth., T. brachyphyllus Müll. Hal. and T. longescens Müll. Hal. are now considered synonymous with the widespread T. longicollis Michx, the type species for the genus.

The artificial cultivation of moss biocrusts can accelerate the recovery of degraded arid lands and is closely related to moss productivity. Understanding the properties of inoculation materials on the regenerative capacity of mosses, in particular the effect of time limits on storage, has the potential to benefit the cultivation of artificial moss biocrusts. We investigated the vegetative regeneration and physiological characteristics of three desiccation‐tolerant mosses (Barbula unguiculata, Didymodon vinealis, and Didymodon tectorum) upon rehydration after periods of desiccation storage for 40, 89, 127, and 197 days. Regenerative capacity, represented by gametophyte vigor index, decreased with increased storage time. The greatest change in vegetative regeneration among storage times was observed in B. unguiculata, where the gametophyte vigor index decreased by 95.74% after 197 days of storage. Over the same period, there were smaller decreases in gametophyte vigor index of D. vinealis and D. tectorum of 42.17% and 13.30%, respectively. Malondialdehyde and soluble sugar increased with longer periods of storage time, while soluble protein content first increased, then decreased. Oxidation levels are important factors influencing the recovery of desiccation‐tolerant mosses. All three moss species regenerated after 197 days of storage, but regenerative capacity is dependent on species. For land managers, biocrust restoration can be facilitated by careful screening of suitable moss species, based on their capacity to regenerate new growth after extended periods of storage and selection of species based on variations in physiological characteristics.

A detailed revision of the genus Trematodon Michx. is given together with a key to species, illustrations and distribution maps for the five species of Trematodon now recognised in Australia. Of the nine species previously recorded for Australia, one species, T. amoenus (Müll.Hal.) I.G.Stone & G.A.M.Scott is endemic while T. flexipes Mitt., T. mackayi (R.Br.bis.) Broth. and T. suberectus Mitt., occur in Australia and New Zealand. Three species previously considered Australian endemics, T. baileyi Broth., T. brachyphyllus Müll.Hal. and T. longescens Müll. Hal., are now considered conspecific with the widespread T. longicollis Michaux, the type species for the genus.

Following a critical re-examination and evaluation of Australian taxa of the genus Trematodon, three species formerly considered endemic, T. baileyi Broth., T. brachyphyllus Müll. Hal., and T. longescens Müll. Hal., together with the New Caledonian endemic T. longifolius Broth. & Paris in Broth., are illustrated for the first time and reduced to synonyms of T. longicollis Michx.

The genus Mesochaete Lindb. is known from tropical to temperate regions of the east coast of mainland Australia and Lord Howe Island. It includes two species, M. undulata Lindb. and M. taxiforme (Hampe) Watts & Whitel. Leaf size, leaf cell dimensions and aspects of leaf cross-sectional anatomy appear to be the most reliable morphological features to distinguish the species and new information is given in support of their retention as separate species. Incorrect statements in the Flora of Australia and other Australian treatments are rectified. As there are no previous illustrations of the sporophyte of M. taxiforme, or descriptions of the peristome and spores of either taxon, complete illustrations of the two Mesochaete species are presented with a supplementary description of the sporophyte and, where available, SEMs of peristomes and spores. One of the taxa, M. taxiforme, was represented by very little fruiting material. Consequently, only one sporophyte was sacrificed for the SEM work. Morphologically, peristomes and spores of both taxa appear almost identical.

Background and Aims Biological soil crusts, comprising assemblages of cyanobacteria, fungi, lichens and mosses, are common in dryland areas and are important elements in these ecosystems. Increasing N deposition has led to great changes in community structure and function in desert ecosystems worldwide. However, it is unclear how moss crusts respond to increased atmospheric N deposition, especially in terms of growth and physiological parameters. The aim of this study was to understand how Syntrichia caninervis, a dominant species in moss crusts in many northern hemisphere desert ecosystems, responds to added N. Methods The population and shoot growth, and physiological responses of S. caninervis to six different doses of simulated N deposition (0, 0·3, 0·5, 1·0, 1·5 and 3·0 g N m–2 year–1) were studied over a 3 year period. Key Results Low amounts of added N increased shoot length and leaf size, whereas high doses reduced almost all growth parameters. Moss shoot density increased, but population biomass decreased with high N. Low N augmented chlorophyll b, total chlorophyll content and soluble protein concentrations, but not chlorophyll a or chlorophyll fluorescence. High N was detrimental to all these indices. Soluble sugar concentration declined with increased N, but proline concentration was not affected significantly. Antioxidant enzyme activities generally decreased with low N additions and increased with high doses of simulated N deposition. Conclusions Low amounts of added N (0–0·5 g N m–2 year–1) may enhance moss growth and vitality, while higher amounts have detrimental effects.

BACKGROUND AND AIMS:Biological soil crusts, comprising assemblages of cyanobacteria, fungi, lichens and mosses, are common in dryland areas and are important elements in these ecosystems. Increasing N deposition has led to great changes in community structure and function in desert ecosystems worldwide. However, it is unclear how moss crusts respond to increased atmospheric N deposition, especially in terms of growth and physiological parameters. The aim of this study was to understand how Syntrichia caninervis, a dominant species in moss crusts in many northern hemisphere desert ecosystems, responds to added N.METHODS:The population and shoot growth, and physiological responses of S. caninervis to six different doses of simulated N deposition (0, 0·3, 0·5, 1·0, 1·5 and 3·0 g N m(-2) year(-1)) were studied over a 3 year period.KEY RESULTS:Low amounts of added N increased shoot length and leaf size, whereas high doses reduced almost all growth parameters. Moss shoot density increased, but population biomass decreased with high N. Low N augmented chlorophyll b, total chlorophyll content and soluble protein concentrations, but not chlorophyll a or chlorophyll fluorescence. High N was detrimental to all these indices. Soluble sugar concentration declined with increased N, but proline concentration was not affected significantly. Antioxidant enzyme activities generally decreased with low N additions and increased with high doses of simulated N deposition.CONCLUSIONS:Low amounts of added N (0-0·5 g N m(-2) year(-1)) may enhance moss growth and vitality, while higher amounts have detrimental effects.

The diversity and functional roles of biocrust bryophytes in different terrestrial habitats are described in this chapter. At present, over 320 species of biocrust bryophytes have been described, many of which belong to the families Pottiaceae and Bryaceae. Bryophytes possess a suite of physiological and morphological traits that enable them to colonize and live in extreme environments. For this reason, bryophytes can be a conspicuous component of biocrust communities in dryland ecosystems as well as polar regions. As poikilohydric plants, adaptations at the cell and shoot and population level permit the tolerance of desiccation as well as temperature stress, but such traits often come at the expense of growth rates and sexual reproduction. Establishment and dominance of bryophytes in biocrusts are dependent on physical factors such as substrate chemistry and aridity and biotic factors such as propagule banks and the presence of other biocrust organisms. Primary colonists such as cyanobacteria and fungi typically facilitate establishment, and bryophytes often occur in the later stages of crust development. Ecologically, biocrust bryophytes provide habitats for other crust community members and also contribute to soil stability, hydrology, and nutrient cycling.

Precipitation is the major driver of ecosystem functions and processes in semiarid and arid regions. Although re-wetting pulses generate a significant portion of the total annual CO2 exchange between atmosphere and soil, there has been little recognition of the importance of photosynthetic and respiratory activities of biological soil crusts (biocrusts) in desert soil CO2 exchange. In this study in the Gurbantunggut Desert of northwestern China, our objective was to determine the extent to which precipitation intensity could influence soil CO2 exchange of the desert ecosystem and the role played by moss crust in soil C balance during this process. In field experiments, net CO2 exchange (NCE) was measured in moss crusted soil and in bareland once a month from March to November in 2013. In laboratory experiments, simulated precipitation treatments (0 mm, 2 mm, 5 mm, 10 mm and 15 mm) were applied to moss crust, and NCE of moss crusted soil and its three flux components (crust photosynthesis, crust respiration, and subsoil respiration) were measured. Temporal variation of NCE varied with soil moisture and temperature. Soil moisture alone can explain 71-74% of variation in NCE. Soil type (moss crusted soil or bareland) also had a significant effect on NCE (P < 0.01), but this was dependent on soil moisture which is directly linked to precipitation pulse. The response of NCE to precipitation pulse in moss crust differed significantly from that of bareland. After a 2 mm precipitation pulse, the crust gross photosynthetic rate (GPc) was lower than the crust respiration rate (Rc), resulting in C efflux. When precipitation intensity was equal to or greater than 5 mm, GPc fully offset total respiration, resulting in an increase in C uptake. C gain was positively correlated with intensity of precipitation pulse. Regardless of different precipitation intensities, Rc was significantly higher than that of subsoil respiration. Thus, precipitation primarily drives moss crust-derived CO2 exchange, which significantly influences the balance of soil-level CO2 exchange in desert ecosystems. Overall, this study demonstrates that in desert ecosystems, the regulation of atmospheric-soil C balance by moss crusts depends on the intensity of precipitation. (C) 2015 Elsevier Masson SAS. All rights reserved.

In spring 2014, thousands of green algal balls were washed up at Dee Why Beach, Sydney, New South Wales, Australia. Reports of algal balls are uncommon in marine systems, and mass strandings on beaches are even more rare, sparking both public and scientific interest. We identified the algal masses as Chaetomorpha linum by using light microscopy and DNA sequencing. We characterize the size and composition of the balls from Dee Why Beach and compare them to previous records of marine algal balls. We describe the environmental conditions that could explain their appearance, given the ecophysiology of C. linum.

Although the desert moss Syntrichia caninervis Mitt. is extremely desiccation tolerant, it still requires water and photosynthates for growth. The ecological significance of the leaf angle in maintaining a balance between water and light availability is critical to its survival. Active leaf repositioning balances water and light availability following rehydration. S. caninervis can adjust leaf angles from a steep (84–69°) to a stable level at 30° within 7 s after rehydration, obtaining maximum net photosynthetic gain at a shoot relative water content of ~60%. Leaf morphological characters, (leaf hair points, surface papillae and costal anatomy) and ultrastructural changes (chloroplast reordering and loss of lipid reserves as shown by changes in osmiophilic globules) were linked to rapid leaf spreading, water gain and sunlight reflectivity of leaves during rehydration. The high 377.20 ± 91.69 (cm2 g–1) surface area to mass ratio was a major factor in facilitating the rapid response to rewetting. Hyaline cells of the leaf base absorbed water, swelled and forced the leaf away from the stem as soon as rehydration commenced. Loss of leaf hair points retards leaf angle adjustment during rehydration.

AimsDesert ecosystems are often characterized by patchy distribution of vascular plants, with biological soil crusts (BSC) covering interplant spaces. However, few studies have comprehensively examined the linkage between BSC and vascular plants through nitrogen (N) or element translocation. The objective of this study was to evaluate the ecological roles of BSC on N translocation from soil to the dominant herb Erodium oxyrrhynchum Bieb. (Geraniaceae) in a temperate desert in China.MethodsIsotopes (including N-15-Glu, N-15-NH4Cl and N-15-NaNO3) were used as a tracer to detect translocation of N in two types of desert soil (BSC covered; bare) to the dominant herb E. oxyrrhynchum. Three different forms of N-15-enriched N compounds were applied as a point source to small patches of BSC and to bare soil. And we measured isotopes (N-14 and N-15) and obtained the concentration of labeled-N-15 in both vascular plants and soils at different distances from substrate applicationImportant FindingsPlants of E. oxyrrhynchum growing in BSC-covered plots accumulated more delta N-15 than those growing in the bare soil. Similarly, soil from BSC-covered plots showed a higher concentration of labeled-N irrespective of form of isotope, than did the bare soil. The concentration of dissolved organic N (N-15-Glu) in E. oxyrrhynchum was higher than that of dissolved inorganic N (N-15-NH4Cl and N-15-NaNO3). Soil covered by BSC also accumulated considerably more dissolved organic N than bare soil, whereas the dominant form of N-15 concentrated in bare soil was dissolved inorganic N. Correlation analysis showed that the concentration of labeled-N in plants was positively related to the concentration of labeled-N in soils and the N% recorded in E. oxyrrhynchum. Our study supports the hypothesis that BSC facilitates N-15 translocation in soils and vascular plants in a temperate desert of northwestern China.

Bryophytes (mosses, liverworts, hornworts) are an abundant and conspicuous component of the World Heritage Gondwana Rainforests of Australia which comprise several discontinuous areas of subtropical forests and woodland along the Great Escarpment of north-eastern New South Wales and south-eastern Queensland. The Gondwana Rainforests are considered to be of exceptionally high conservation value, with more than 200 rare or threatened plant and animal species but, surprisingly, no mention is made of bryophytes in the statement of outstanding universal values. Recent studies in Werrikimbe and Willi Willi National Parks using bryophytes as fine-scale indicators of rainforest condition, have identified a number of unusual and interesting bryophytes including the moss Rosulabryum epiphyticum (Bryaceae), Leptodontium viticulosoides, (Pottiaceae) and several endemic species of Macromitrium (Orthotrichaceae) The moss Fissidens thorsbornei (synonym: Nanobryum thorsbornei) (Fissidentaceae) and the liverwort Lejeunea gracilipes (Lejeuneaceae), are reported as new records for New South Wales.

Community structure and species composition are closely related to plant diversity and ecosystem stability. To explore the similarity in vegetation structure of shrub communities under the same temperate climate but with different microhabitats, 36, 28 and 13 sampling plots in Ephedra distachya, Seriphidium terrae-albae and Artemisia songarica communities were selected respectively, during the course of three seasons (early spring, summer, autumn) in Gurbantunggut Desert, north-western China. The species composition, abundance, biomass and soil nutrients were investigated. Floristic changes were characterized by similarity and ordination methods.Two communities, E. distachya and S. terrae-albae, were similar in terms of soil nutrients but differed from the A. songarica community. Soil organic matter, nitrogen and biological soil crusts accounted for the differences of microhabitats. In spring and summer, more plant families, genera and species were recorded in E. distachya and S. terrae-albae communities than in the A. songarica community but in each community, the number of families, genera, species, herbs and life forms showed a consistent trend summer > spring > autumn. There were significant differences in absolute biomass among the three communities, but the ratio of dead biomass to total biomass was consistently 1:4, indicating the constant turnover rate of plant biomass for nutrient cycling. In each community shrubs accounted for the most biomass. Herbaceous biomass was negligible but the herbs contributed the most richness and abundance.The similarity in response of all three communities to seasonal changes in vegetation structure and biomass allocation demonstrate convergence although divergence is demonstrated in soil characteristics or microhabitats.

The distribution, population sizes and habitat preferences of the rare tree ferns Cyathea cunninghamii Hook.f. (Slender Tree Fern) and F1 hybrid Cyathea x marcescens N.A.Wakef. (Skirted Tree Fern) in south-eastern Australia are described, together with the extension of the known distribution range of Cyathea cunninghamii from eastern Victoria into south-eastern New South Wales. Floristic and ecological data, encompassing most of the known habitat types, vegetation associations and population sizes, were collected across 120 locations. Additional information was sought from literature reviews, herbarium collections and field surveys of extant populations. Cyathea cunninghamii is widespread, with the majority of populations occurring in Tasmania and Victoria, one population in south-eastern NSW and a disjunct population in south-eastern Queensland; Cyathea x marcescens is confined to south and eastern Victoria and south and north eastern Tasmania. Both taxa occur on King Island in Bass Strait. Both taxa have a near coastal distribution with most populations occurring in sub-coastal hinterland and escarpment forests with a median altitude of 288 m. Hierarchical cluster analysis of floristic data across the species' geographic range identified six vegetation communities ranging from rainforest to damp sclerophyll forest. Their micro-habitat preferences were consistently identified as steeply incised gullies of minor headwater streams of coastal and sub-coastal ranges with a plentiful moisture regime and geomorphic protection from extreme stream flow events, flooding and bank scouring. Sporophyte recruitment was associated with exposed soil of stream banks and edges of constructed walking tracks. Population sizes of both taxa are small with the majority of populations consisting of less than five adult individuals, with total populations of Cyathea cunninghamii and Cyathea x marcescens estimated at 919 and 221 mature individuals respectively. Population extinctions in Victoria and Tasmania have primarily been associated with outlier populations in regions subject to agricultural land clearance, habitat modification and changes to fire regimes in crown forests. Non- anthropogenic mortality was associated with land slips, tree falls and stream bank scouring by flood water. Conservation of the hybrid Cyathea x marcescens necessitates the preservation of habitats where both Cyathea cunninghamii and Cyathea australis occur in close proximity to substrates suitable for spore germination. In future, molecular techniques may prove useful for field identification of juvenile stages, facilitating selection of progeny of Cyathea cunninghamii and Cyathea x marcescens for cultivation and re-introduction to sites of previous or possible future extinctions.

Syntrichia caninervis Mitt. is the dominant species in the moss crusts of the Gurbantunggut Desert, a cold, northern desert of Central Asia. Most studies of bryophyte desiccation tolerance have been of Tortula (Syntrichia) ruralis. The two species are closely related and any physiological work on one is likely to be relevant to the other. Changes in membrane structures in this species were monitored under varying conditions of water stress in this study. Microscopical and physiological tests were conducted. No significant changes in electrical conductivity of the rehydration water were observed either during dehydration or rehydration. Electron micrographs of the fine-structure of leaf cells were obtained through a drying-re-wetting cycle. Major changes in cell ultrastructure were observed over time but there was no evidence of membrane damage during either desiccation or rehydration. Three possible explanations for disorganized or disrupted membranes in the desiccated state are considered: (1) S. caninervis has special morphological and anatomical characteristics (e.g. strong leaf costa which can transport water during the recovery state) that allow it to survive in an hostile, arid environment, and cellular structures that remain intact in the desiccated state permitting membrane integrity to be rapidly regained during rehydration; (2) the moss quickly becomes dormant during dehydration but maintains a certain level of membrane integrity; and (3) during desiccation, rapidly and continuously increasing amounts of both soluble sugar (major 'constitutive' protective substances) and free proline contribute to membrane stabilization.

Identifying the patterns of soil microbial responses to increasing nitrogen (N) availability are important since microbial processes are related to the potential nutrient transformations. The effects of the addition of N to the soil microbial community of the Gurbantunggut Desert, China, are described in this paper. The study was conducted over a two-year period with trials commencing at the beginning of each growing season. Soil enzyme activity, microbial biomass and microbial community level physiological profile (CLPP) were determined at 0-5 cm and 5-10 cm soil depths. Nitrogen was added to the soil at five rates plus a control, i.e. 0, 0.5, 1, 3, 6 and 24 g N m(-2) y(-1). We hypothesized that soil enzyme activities and microbial biomass N (MBN) would firstly increase and then decrease, and CLPP would be altered with increasing N addition, due to the deleterious effects of higher N addition upon microbial activity. Because of the relatively higher organic matter in the upper depth of soil layers, we further hypothesized that the responses of microbial activities in the 0-5 cm depth would be more marked than at 5-10 cm. In partial support of our hypothesis, soil enzyme activities, microbial biomass and nutrient concentrations responded to N addition with the most significant changes occurring in the 0-5 cm soil depth. Addition of N resulted in an increase in MBN and a decrease in urease activity. Invertase and alkaline phosphatase (AIP) activities increased at low doses of N addition and showed a decrease at higher doses. There was no evidence of change in oxidative enzyme activity at low N treatments but activity decreased at high N additions. However, the CLPP was not affected by N addition. The results of this study suggest that N supplementation in this desert soil may affect C transformation, increase availability of N and P. and immobilize N in the microbial biomass. Responses of the enzyme activity to N supplementation occurred within the context of an apparently stable or unresponsive microbial community structure. (C) 2011 Published by Elsevier Ltd.

In Gurbantunggut Desert, cyanobacterial and microalgal components were characterized within 60 soil samples collected from sand dunes. Fifty-one taxa of cyanobacteria and algae were identified. Without exception, the soils were alkaline, poor in nutrients, and showed large variations in other soil properties. Spatial heterogeneity for distribution of cyanobacteria and microalgae (diversity of morphotypes, species composition, and microbiomass) existed. Compared with other deserts in the world, the Gurbantunggut Desert has a greater diversity of cyanobacterial-microalgal morphotypes. Results from step regression showed that the diversity of morphotype was determined by total P, available P, and soil layer. Filamentous cyanobacteria dominated the community. Microcoleus vaginatus (Vauch.) Gom was the dominant species in most positions on sand dune, while the abundance of other dominant species varied depending on the sand dune position and the soil layer in which they occurred. The microalgal biomass was influenced by the content of Mg, crust type, soil moisture, sunlight, and oxygen concentration. A significant positive relation was found between microalgal biomass and diversity of morphotype. Species composition, diversity of morphotype, and microalgal biomass interacted with each other. The contents of P and Mg ion, soil texture, and soil moisture may be the main factors responsible for cyanobacterial-microalgal distribution.

Two annual desert plants, Malcolmia africana (L.) R.Br. (Brassicaceae) and Bassia hyssopifolia (Pall.) Kuntz (Chenopodiaceae) were selected to determine the combined effects of nitrogen deposition and water stress on their growth and physiological responses. Nitrogen addition and water stress significantly affected growth of both species. Root weight, leaf number, average leaf area, total biomass, and the shoot/root ratio increased with N addition. For both species, increasing N levels were correlated with higher concentrations of chlorophyll and soluble proteins, higher net photosynthetic rates, and lower content of soluble sugars and proline. M. africana was more sensitive to water stress than B. hyssopifolia , but few differences were observed between the species in their response to N addition. The negative effects of water stress on growth and physiological responses were partly compensated by increased N supply. Overall, the results suggest that N deposition could lead to an increase in annual plant growth in the Gurbantunggut Desert in northwestern China.

Dew is an important source of moisture for plants, biological soil crusts, invertebrates and small vertebrates in desert environments. In this paper, measurements were taken to investigate the effects of three different types of biological soil crusts (cyanobacteria, lichen and moss) and bare sand on dew deposition in the Gurbantunggut Desert. Dew quantities were measured using micro-lysimeters with a diameter of 6 cm and a height of 3.5 cm. The results showed that the total amount of dew deposited increased with the development of soil crusts, from bare sand to cyanobacterial crust to lichen crust to moss crust. The average amount of dew deposited daily on the moss crust was the highest of all and it was significant higher than the other three soil surfaces (lichen crust, cyanobacterial crust and bare sand) (p < 0.05). During the period of the study, for each type of crust studied, the maximum amount of dew recorded was several times greater than the minimum. Moss crust was characterized by having the greatest amount of dew at dawn and also the maximum amount of dew deposited, whereas bare sand yielded the lowest amount of dew, with lichen crust and cyanobacterial crust exhibiting intermediate values. However, this was not the case for dew duration, as bare sand retained moisture for the longest period of time, followed by cyanobacterial crust, moss crust and finally lichen crust. Dew continued to condense even after sunrise. Furthermore, the differences in dew deposition may be partially attributed to an effect of the biological soil crusts on surface area. This study demonstrates the important effect of biological soil crusts upon dew deposition and may assist in evaluating the role of dew in and and semi-arid environments. (C) 2009 Elsevier B.V. All rights reserved.