Continental Antarctica is a polar desert containing sparse pockets of vegetation within ice-free areas. Despite the recognized association between lichens, mosses and epiphytic diatoms, the environmental factors controlling diatom community structure are poorly understood. We investigated the association between diatom communities and host vegetation characteristics by experimentally adding nutrients and/or water to two bryophyte (healthy and moribund) and two lichen (crustose and Usnea) vegetation types in the Windmill Islands. Diatom communities were morphologically characterized, diversity indices calculated and differences between treatments, vegetation type and vegetation characteristics tested. We identified 49 diatom taxa, 8 of which occurred with > 1% relative abundance. Bryophyte and lichen vegetation harboured significantly different diatom communities, both in composition and diversity indices. Specifically, Luticola muticopsis was more prevalent in moribund bryophytes and crustose lichens, and Usnea lichens showed lower species richness than other types. While nutrient and water additions did not significantly alter diatom communities, diversity indices and some species showed relationships with vegetation physiological characteristics, notably %N and δ13C, suggesting the importance of ambient gradients in water and nutrient availability. Collectively, this work suggests that future conditions favouring the dominance of a particular vegetation type may have a homogenizing effect on the terrestrial diatom communities of East Antarctica.

National vegetation classification (NVC) has been widely applied as a framework for mapping and conserving plant species and community types. However, a limited availability of expertise has prevented NVCs from being developed and used in cryptogam-dominated systems, such as for temperate and boreal epiphyte communities. This study simplified a recent systematically sampled NVC, trialled for epiphyte communities in Scotland, by reducing the original list of 82 community indicators to 34 easily recognisable species (lichens, mosses and liverworts). These were subsequently sampled from woodland sites positioned in Scotland’s temperate rain forest zone. Sites were positioned among localities in less intensively managed landscapes (northwest Scotland) through to peri-urban environments (southern Scotland), grouping sites for each locality based on a contrast in woodland temporal continuity (ancient or recent). The richness and diversity of epiphyte community indicators were compared with easily measured variables reflecting stand heterogeneity or ecological stability, and woodland temporal continuity, with air pollution as a covariable. Richness and diversity were significantly explained by the ecological stability of woodland stands, heterogeneity of the light environment, and nitrogen pollution. This demonstrates a tool that can be deployed by the non-specialist, with appropriate training, to quantify the condition of a woodland stand through consequences for its epiphytes in globally important temperate rain forest. The pattern of richness and diversity was consistent with the co-occurrence of particular indicator species, which represent the range of epiphyte community types supported by a woodland.

In this paper, we synthesize recorded observations of moss, lichen and bird species in Bunger Hills, East Antarctica, and assess the role of environmental controls, including sediment, salinity, moisture and geology, on species' distributions. The distribution of snow petrels (Pagodroma nivea) appears to be associated with geology; they nest by preference in crevices in bedrock outcrops around the margins of the hills or wherever jointed cliffs are found. South polar skuas (Catharacta maccormicki) are seen throughout Bunger Hills, where they nest and prey on snow petrels. Mosses and lichens were most abundant around the ice margins where fresh snow and ice meltwater are abundant. In the central area of Bunger Hills, where the highest salt concentration in sediments is found and exposure to abrasion by wind-driven mineral sand grains and ice particles is greatest, mosses and lichens are reduced in abundance and diversity. Exposure of parts of Bunger Hills from the ice sheet throughout the Last Glacial Maximum, c. 20 ka bp, means that some land and lakes could have acted as regional refugia and as a locus of recolonization of other ice-free areas.

The Antarctic Treaty recognizes the outstanding scientific values of the Antarctic environment through the designation of Antarctic Specially Protected Areas (ASPAs) that have rigorous management plans specific to each site. Deception Island has the largest concentration of rare bryophyte species and communities in Antarctica, while also offering substantial opportunities for research in a range of scientific disciplines due to its volcanic nature. As a result, conflicts between research interests and conservation goals may arise. On the summit ridge of Caliente Hill severe trampling damage to the moss assemblages growing in association with localized geothermal activity was observed. The range of species affected included the entire known population of Schistidium deceptionense, an endemic moss known only from this site, as well as other very rare Antarctic mosses (Ditrichum ditrichoideum, Bryum orbiculatifolium, Bucklandiella subcrispipila, Pohlia wahlenbergii and Dicranella hookeri). A photomapping study was undertaken to characterize further the status of the site and monitor changes within it. Increased awareness, co-ordination of activities and a spatial zoning within the site could help mitigate damage from permitted activities. Nevertheless, prioritization of longer term conservation goals over short-term research interests may ultimately be necessary where local human impact cannot be managed by other means.

Coarse deadwood provides an important habitat for a suite of niche-specialist lichens in old-growth forests, for example, snags (standing dead trees) and fallen logs. Conversely, the scarcity of deadwood in managed forests is a limiting factor to lichen diversity, though cut stumps may provide an alternative habitat for deadwood species. The surface of cut stumps is an ecologically useful study system, facilitating standardized sampling with which to determine the pattern and process of deadwood succession. This study examined vegetation patterns for the surface of cut stumps at Abernethy RSPB Reserve in northern Scotland. We demonstrate the interrelationship between key topographic, management and edaphic factors during a successional process of terrestrialization. Consequently, we recommend that deadwood diversity might be maximized by 1) creating managed plots with varying degrees of canopy openness for sites with different levels of topographic exposure, and 2) providing cut stumps at different heights within plots, to ensure that during a rotational period the process of terrestrialization operates at different speeds among individual microhabitats. The study examined successional processes on cut stumps using two recently accessible and powerful statistical methods: 1) nonparametric multiplicative regression (NPMR), and 2) multivariate regression trees (MRT). The principles on which these techniques are based are becoming the preferred statistical framework with which to provide robust interpretation of field-sampled data; they are unconstrained by prior assumptions as to the form of a species' niche response, and are data-led models evaluated based on cross-validated performance, thereby avoiding the complication of multiple hypothesis tests.

We have sequenced the 18S–26S nuclear ribosomal DNA ITS region from the genome of nine different moss species from the Ross Sea region of Antarctica. This relatively quick and simple technique enables these species to be readily distinguished, facilitating their taxonomic identification. Only a single moss shoot is required, and for identification of these bryophytes it is only necessary to determine a few hundred nucleotides of the DNA sequence in a single sequencing reaction. Several previously unidentified Antarctic moss specimens were readily characterized by comparison with ITS sequences of known moss species. The relationships between species and locations previously detected by the RAPD (Random Amplified Polymorphic DNA) technique were confirmed by DNA sequencing, demonstrating that the two techniques can be complementary for molecular analysis of the ecology of mosses in Antarctica.

Abundant immature sporophytes of the moss Pottia heimii are reported from the Lower Taylor Valley, McMurdo Dry Valleys and from Cape Chocolate, Victoria Land. These finds extend the reported southern limit for the occurrence of abundant moss sporophytes to 77° 55′S.

The role of carbonic anhydrase in the carbon-concentrating-mechanism of bryophytes of the class Anthocerotae was investigated by comparing the gas-exchange characteristics of material which had been incubated in the membrane-permeable Carbonic Anhydrase inhibitor ethoxyzolamide, with those of untreated material and material which had been incubated in buffer solution. In Phaeoceros laevis (Anthocerotae), incubation in ethoxyzolamide caused a depression in the rate of gross assimilation and a decrease in CO2 affinity beyond that which could be attributed to increased diffusion limitation. A range of liverworts and mosses, in which a carbon-concentrating-mechanism is absent, were also investigated. These showed no depression of rates of gross assimilation after incubation in ethoxyzolamide relative to those of untreated material. The CO2 compensation point and CO2 uptake characteristics of Phaeoceros laevis were significantly affected by incubation in ethoxyzolamide. Values of CO2 compensation point for Phaeoceros laevis rose from 2.5 Pa, after incubation in buffer, to 20 Pa after incubation in ethoxyzolamide. The CO2 compensation point for the liverworts Pellia epiphylla and Marchantia polymorpha was not significantly affected by incubation in ethoxyzolamide. Measurements of the release of CO2 at the end of a short (15 min) period of illumination revealed that, after suppression of carbonic anhydrase activity, the rapid release of a CO2 pool occurred in Phaeoceros laevis but not in the liverworts. There were also significant differences between values for fractionation measured in units per mil (‰), measured instantaneously, for Phaeoceros laevis incubated in ethoxyzolamide, compared with fractionation values for this species after incubation in buffer. Incubation in ethoxyzolamide caused fractionation values to rise from 12.4–22.7‰, indicating that the carbon-concentrating-mechanism of this species had been inactivated. Incubation in ethoxyzolamide had no effect on fractionation values for the liverworts. The convexity of the light saturation curves of liverworts and Phaeoceros laevis was also investigated, but there were no differences between groups before or after the two treatments. The data indicate an important role for carbonic anhydrase in the functioning of the carbon-concentrating-mechanism in the Anthocerotae.