Lichen communities in Larsemann Hills, East Antarctica (original) (raw)
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Antarctic Science, 2008
In the austral summer of 1991-92, 120 sample plots were established along 11 transects at various distances from the Swedish research stations Wasa and Svea in Dronning Maud Land, Antarctica. These plots were re-examined in 2001 -02 to evaluate overall changes and possible local impact from human activities around the research stations on the terrestrial vegetation, formed by lichens and mosses. The results showed high consistencies over the ten years, but nevertheless suggest a slight overall increase in both lichen species density and abundance, measured as the number of lichen records. We did not find evidence for any severe human impact on the lichens and mosses around the research stations. However, sample plots located close to the Svea station had been affected by station maintenance, which has caused local decline of lichen species such as Umbilicaria decussata. In contrast to the overall consistency and slight increase in lichens we found a decline of Rhizoplaca melanophthalma.
The distribution of lichens and mosses at Edward VII Peninsula, Marie Byrd Land, Antarctica
Antarctic Science
This is the first detailed study of the distribution of mosses and lichens at Alexandra Mountains and Rockefeller Mountains, Edward VII Peninsula, Antarctica. A total of 418 samples was collected on 21 nunataks in the summer of 1987–1988. Lichens included 44 taxa, bringing the total known from Edward VII Peninsula to 50. Ten lichen species were new records for the Continental Antarctic zone, whilst only six were endemic to that zone. There were six species and one variety of moss, bringing the total known from Edward VII Peninsula to seven species and one variety. These included the first record of a species of Orthotrichum in Continental Antarctica. Two other species and a variety were new records for Edward VII Peninsula. Overall, the flora was species rich for a Continental Antarctic region and was comparable with the species-rich sites of Botany Bay and Kar Plateau, which are at approximately the same latitude (77°S) in southern Victoria Land. This rich flora was probably suppor...
Czech Polar Reports , 2011
Antarctic terrestrial ecosystems experience some of the most extreme growth conditions, where plant distribution is determined by favourable environmental gradients of temperature and moisture along with micro-topography of habitats. Lichens are among the most tolerant symbiotic organisms which constitute dominant component in the terrestrial biota of Antarctica. There are various studies dealing with patterns of lichen diversity of various regions of Antarctica are done but in east Antarctica such studies are scanty. Lichen synusiae of Schirmacher Oasis and McLeod Island, Larsemann Hills, East Antarctica were studied in order to determine their morphological and substratum affinities. The Lichen synusiae of the study sites was represented by 71 species, 24 genera and 13 families in Schirmacher Oasis and 27 species, 18 genera and 10 families in McLeod Island, Larsemann Hills. Hierarchical cluster analysis of lichen communities on the basis of growth form diversity and substratum occurrence showed that crustose growth form and saxicolous (on rock, stones and moraines) habitat were the most preferred, in both study sites. The study presents a representative account of morphological and substratum preference patterns in lichen synusiae of east Antarctica, which can be of fundamental importance for future lichenological investigation in the region.
Contrasting patterns in lichen diversity in the continental and maritime Antarctic
Polar Science, 2015
Systematic surveys of the lichen floras of Schirmacher Oasis (Queen Maud Land, continental Antarctic), Victoria Land (Ross Sector, continental Antarctic) and Admiralty Bay (South Shetland Islands, maritime Antarctic) were compared to help infer the major factors influencing patterns of diversity and biogeography in the three areas. Biogeographic patterns were determined using a variety of multivariate statistical tools. A total of 54 lichen species were documented from Schirmacher Oasis (SO), 48 from Victoria Land (VL) and 244 from Admiralty Bay (AB). Of these, 21 species were common to all areas. Most lichens from the SO and VL areas were microlichens, the dominant genus being Buellia. In AB, in contrast, many macrolichens were also present and the dominant genus was Caloplaca. In SO and VL large areas lacked any visible lichen cover, even where the ground was snow-free in summer. Small-scale diversity patterns were present in AB, where the number of
Diversity of lichens in Antarctica
The onl1, extont li<hen fora of Antat.ticz, Mt of C WDodge, Published in 1973. includes 415 species, 44.6'% of nhich vere described b1' Dodge os nex to science. We haw recentll, exttnittet! the typesof 152 r ofa total of 186) species des<ribed b1'Dodge and accept onll' 3l species ( 2O/,) as ralid. All of Dodge's species rere des$ibed os endemic to Antarctica: aflet rc\ision A larctica has lost l2l endernic lichens. On the other hand, recent lichenologicol rcseorch it Antarclica hos added nany lichen species to its lichenfora. This papet summari:es the results of the last 20 years of lichenolog' ical explorution of Anlordica, and co,tsidef lhe main fotitlic-Phltogeographic elemen$ in the fora. The knolrn lichen foru of Antarc ca is reduced from 415 to 260 species, the percentage of endemic species falls lron 9l'%' to 3B%, and that of bipolar and cosmopoliton species increases fron 2.4j1' to 41,5%', Although these figutes are likely ,o change in the neor futu,'e as a consequence of lhe presenl intensive lichenological research in 'lntarctica, they suggest that the lichen fora of lhe continent, and especially of continental Antarctica, is a )oung one' n'hich motuly originated br-long4istance dispersal in lhe Qu4ternqt| period-
. Diversity and ecophysiology of lichens in Schirmacher Oasis, Antarctica
Ministry of Earth Sciences, New Delhi, 2019
Lichens are the most successful organisms in Antarctica that are morphologically and physiologically adapted to harsh environment of the continent. In the past Indian researchers have contributed significantly to the lichen study in Schirmacher Oasis, East Antarctica, but it is strongly felt that there is still scope for lichen exploration in this region. Therefore, the present study was undertaken with three objectives-to consolidate the earlier work and prepare a checklist of lichens; to study the physiology (photosynthesis and water relation) of with respect to desiccation and high light tolerance; and to assess water utilization and climate change response in lichens using carbon isotope ratios. A total of 25 lichen species are collected in present expedition among them Buellia latemarginata is new to Schirmacher Oasis. The consolidation of all studies on Schirmacher Oasis lichens revealed occurrence of 70 species under 23 genera and 12 families in the region.The water holding capacity of foliose lichen Umbilicaria antarctica was maximum with 204.5% while it was least in crustose lichen Acarospora gwynii(44.9%). According to the parameters of Pressure Volume Curve derived from Thermocouple Psychrometric technique Rhizoplaca melanophthalma, a squamulose lichen growing over soil in dry, exposed areas can be considered as highly desiccation tolerant species. R. melanophthalma exhibited lowest (3.98 ± 2.95) elasticity modulus, low Osmotic Potential at full turgor (-0.90 ± 0.29), lesser apoplastic water content (12.29 ± 7.34), and low Relative Water Content at turgor loss (67.43 ± 8.02). Similarly, Xanthoria elegans, a foliose lichen can be considered as photosynthetically active and photo-tolerant species in the region which had chlorophyll a-0.405 ± 0.021, chlorophyll b-0.076±0.010, total chlorophyll-0.211±0.017, carotenoid 0.165±0.003, protein-0.909 ±0.246, chlorophyll fluorescence Fv/Fm-0.62 ± 0.067. The carbon isotope discrimination study indicated that photobionts in lichens growing at water drainage areas of Schimarcher Oasis have CO 2 Concentrating Mechanism (CCM) in their photosynthesis cycle. It is observed that 13 C in lichens growing in dry areas was much depleted (-24.725 ± 2.046 ‰) than those growing in drainages (-21.006 ± 1.610 ‰). The climate change study revealed that 13 C of the atmosphere in Antarctica is steadily depleted within a span of 18 years with-7.780 ± 0.020‰ during 1992 to-8.174 ± 0.018‰ in 2008 (p = 0.0001). However, lichens of Schirmacher Oasis exhibited an opposite trend which indicates the changing preference of Antarctic lichens towards 13 C than 12 C may be as an adaptation to changing climate.
Antarctic Science, 2010
There are marked declines in precipitation, mean temperatures and the number of lichen species with increasing latitude in Antarctica. However, it is not known which factors are the predominant controllers of biodiversity changes. Results are presented from over two years of almost continuous monitoring of both microclimate and activity in lichens at Livingston Island, South Shetland Islands, 628S, and Botany Bay, Ross Sea region, 778S. Lichen activity was evident over a much longer period at Livingston Island, (3694 versus 897 hours) and could occur in any month whereas it was almost completely confined to the period November-February at Botany Bay. Mean air temperatures were much lower at Botany Bay (-188 compared to -1.58C at Livingston Island), but the temperatures at which the lichens were active were almost identical at around 28C at both sites. When the lichens were active incident light at Botany Bay was very much higher. The differences are related to the availability of meltwater which only occurs at times of high light and warm temperatures at Botany Bay. Temperature as a direct effect does not seem to explain the differences in biodiversity between the sites, but an indirect effect through active hours is much more probable. In addition there are negative effects of stresses such as high light and extreme winter cold at Botany Bay.