Morphological variation and taxonomic interpretation in the moss genus Bryum in Antarctica

The potential for morphological variation in Antarctic species of Bryum is evaluated and related to problems associated with taxonomic interpretation based on specimens from the Soya Coast, Mac. Robertson Coast, Vestfold Hills and Knox Coast. B. argenteum HEDW. Has been positively determined for Continental Antarctica from six localities on the Soya Coast and from Ross Island, southern Victoria Land. Specimens from the Vestfold Hills and Knox Coast considered with some reservation as this species are here referred to B. pseudotriquetrum (HEDW.) GAERTN, MEYER et SCHERB. B. pseudotriquetrum is widespread in the Antarctic region and includes many species formerly regarded as distinct taxa. Small specimens and those with physical damage to the upper parts of leaves may confused with B. argenteum. It is concluded that only two species of Bryum, B. argenteum and B. pseudotriquetrum, are represented in the Continental Antarctic flora, confirming H. OCHI\u27S (Mem. Natl Inst. Polar Res., Spec. Issue, 11, 70, 1979) taxonomic conclusion

Extreme southern locations for moss sporophytes 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

Quantified vegetation change over 42 years at Cape Hallett, East Antarctica

This paper reports on the remapping of a carefully documented vegetation plot at Cape Hallett (72°19′S 170°16′E) to provide an assessment of the rates of vegetation change over decadal time scales. E.D. Rudolph, in 1962, mapped in detail the vegetation of a site approximately 28 m by 120 m at Cape Hallett, Victoria Land, Antarctica. This site was relocated and remapped in January 2004 and changes were assessed using GIS techniques. This appears to be the longest available time period for assessing vegetation change in Antarctica. The analysis indicated that considerable change had occurred in moss and algae distribution patterns and this seems to have been caused by increased water supply, particularly in wetter areas. There was also evidence of some change in lichen distribution. The extent of the change indicates that vegetation cover can be used for monitoring change in areas as extreme as the Ross Sea region. For this analysis to be successful it was important that the mapping techniques used were totally explicit and could easily be replicated. Fortunately, Rudolph had defined his cover classes and the site was also clearly marked. The application of GIS mapping techniques allows the mapping to be more explicitly defined and easily replicated

Photosynthetic performance of Xanthoria mawsonii C. W. Dodge in coastal habitats, Ross Sea region, continental Antarctica

Xanthoria mawsonii C. W. Dodge was found to perform well physiologically in a variety of habitats at high latitudes in continental Antarctica. The net photosynthetic rate of 7•5 μ mol CO2 kg−1 s−1 is exceptionally high for Antarctic lichens. Field and laboratory measurements proved the photosynthetic apparatus to be highly adapted to strong irradiance. The cold resistance of the photosystem II reaction centres is higher than the photosynthetic CO2 fixation process. Optimum temperature for net photosynthesis was c. 10°C. The lichen grows along water channels where it is frequently inundated and hydrated to maximum water content, although net photosynthesis is strongly depressed by super saturation. In these habitats the lichen is photosynthetically active for long periods of time. Xanthoria mawsonii also grows at sites where it depends entirely on the early spring snow melt and occasional snow fall for moisture. It has an exceptionally short reactivation phase and is able to utilize snow immediately. Recovery of activity by absorbing water vapour from air, though practically possible, seems to be of ecological importance only under snow at subzero temperatures

Photosynthetic responses of three common mosses from continental Antarctica

Predicting the effects of climate change on Antarctic terrestrial vegetation requires a better knowledge of the ecophysiology of common moss species. In this paper we provide a comprehensive matrix for photosynthesis and major environmental parameters for three dominant Antarctic moss species (Bryum subrotundifolium, B. pseudotriquetrum and Ceratodon purpureus). Using locations in southern Victoria Land, (Granite Harbour, 77°S) and northern Victoria Land (Cape Hallett, 72°S) we determined the responses of net photosynthesis and dark respiration to thallus water content, thallus temperature, photosynthetic photon flux densities and CO2 concentration over several summer seasons. The studies also included microclimate recordings at all sites where the research was carried out in field laboratories. Plant temperature was influenced predominantly by the water regime at the site with dry mosses being warmer. Optimal temperatures for net photosynthesis were 13.7°C, 12.0°C and 6.6°C for B. subrotundifolium, B. pseudotriquetrum and C. purpureus, respectively and fall within the known range for Antarctic mosses. Maximal net photosynthesis at 10°C ranked as B. subrotundifolium > B. pseudotriquetrum > C. purpureus. Net photosynthesis was strongly depressed at subzero temperatures but was substantial at 0°C. Net photosynthesis of the mosses was not saturated by light at optimal water content and thallus temperature. Response of net photosynthesis to increase in water content was as expected for mosses although B. subrotundifolium showed a large depression (60%) at the highest hydrations. Net photosynthesis of both B. subrotundifolium and B. pseudotriquetrum showed a large response to increase in CO2 concentration and this rose with increase in temperature; saturation was not reached for B. pseudotriquetrum at 20°C. There was a high level of variability for species at the same sites in different years and between different locations. This was substantial enough to make prediction of the effects of climate change very difficult at the moment

Selecting and Testing Cryptogam Species for Use in Wetland Delineation in Alaska

To support the determination of hydrophytic vegetation in wetland delineations in Alaska, USA, a series of tests were conducted to develop a group of “test positive” species to be used in a “cryptogam indicator.” In 2004, non-vascular cryptogam species (bryophytes, lichens, and fungi) from Interior and South-Central Alaska in the vicinities of Fairbanks and Anchorage were collected at a series of ten 50 × 50 cm plots along two 30 m transects in each of six upland and five wetland sites. Nineteen moss and liverwort species were selected from 86 species surveyed to test for wetland fidelity. In 2005, a plot-based analysis of frequency and cover data yielded a revised list of 17 bryophyte species that were specific to wetland communities dominated by black spruce, Picea mariana (P. Mill.) B.S.P. Fungi and lichens were found to be inadequate wetland indicators in the sampled locations because the lichen species were sparsely distributed and the fungi were too ephemeral. The cryptogam indicator was thus restricted to bryophytes. Also in 2005, bryophytes were analyzed for their presence on microtopographic positions within the landscape, including tops of hummocks and hollows at the bases of hummocks. Upland bryophyte species were found on hummock tops inside the wetland boundary, but were not abundant in the hollows (p < 0.05). The fidelity of the species selected for use in the cryptogam indicator was tested. It was determined that if more than 50% of all bryophyte cover present in hollows is composed of one or more of the 17 wetland bryophytes tested in 2005, then vascular vegetation can be considered to be hydrophytic (p < 0.001).Afin d’étayer la présence de végétation hydrophytique dans les délimitations de zones humides de l’Alaska, aux États-Unis, une série de tests a été effectuée dans le but d’aboutir à un groupe d’espèces « de test positives » à utiliser avec un « indicateur de sporophyte ». En 2004, des espèces de sporophytes non vasculaires (bryophytes, lichens et champignons) de l’intérieur et du centre-sud de l’Alaska, aux environs de Fairbanks et d’Anchorage, ont été recueillies à une série de dix parcelles de 50 sur 50 cm le long de deux transects de 30 m dans chacun de six sites montagnards et de cinq sites humides. Dix-neuf espèces de mousse et d’hépatiques ont été choisies à partir de 86 espèces prélevées dans le but d’en déterminer la fidélité aux zones humides. En 2005, une analyse de fréquence de parcelles et des données de couverture ont permis d’obtenir la liste révisée de 17 espèces de bryophytes propres aux zones humides dominées par l’épinette noire, Picea mariana (P. Mill.) B.S.P. Nous avons constaté que les champignons et les lichens étaient des indicateurs de zones humides inadéquats aux sites échantillonnés parce que les espèces de lichen étaient réparties maigrement et que les champignons étaient trop éphémères. Par conséquent, l’indicateur de sporophytes a été restreint aux bryophytes. Également en 2005, nous avons analysé les bryophytes afin d’en déterminer la présence à des positions microtopographiques du paysage, ce qui comprenait le sommet de hummocks et les creux à la base de hummocks. Des espèces de bryophytes montagnardes ont été décelées aux sommets de hummocks à l’intérieur de la limite des zones humides, mais celles-ci n’abondaient pas dans les creux (p < 0.05). La fidélité des espèces choisies afin d’être utilisées dans l’indicateur de sporophytes a été testée. Nous avons déterminé que si plus de 50 % de toute la couverture de bryophyte présente dans les creux est composée de l’une ou plusieurs des 17 bryophytes de zones humides testées en 2005, la végétation vasculaire peut alors être considérée comme hydrophytique (p < 0,001)

Trematodon (Bryopsida: Bruchiaceae) in Australia: unravelling the conundrum

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

Drepanocladus longifolius (Amblystegiaceae), an addition to the moss flora of King George Island, South Shetland Islands, with a review of Antarctic benthic mosses

Abstract Drepanocladus longifolius (Mitt.) Paris is recorded for the first time from King George Island, South Shetland Islands, in the maritime Antarctic. It was collected in West Lake during the 23rd Chinese National Antarctic Research Expedition in 2006-2007. The moss was found at a depth of 5-6 m attached to the bed of the lake. The stems of the moss are about 1-1.5 m in length. The moss exhibits seasonal growth patterns, with shorter branch internodes, more widely spaced leaves and more branches in summer than in winter. Most of the branches are initiated in summer. The annual shoot extension is about 3-6 cm, which implies that the plants must be at least 15 years of age. The distribution of aquatic moss species and records in Antarctica is outlined and discussed and the nomenclature of previous reports clarified