Ecology of endolithic lichens colonizing granite in continental Antarctica

In this study, the symbiont cells of several endolithic lichens colonizing granite in continental Antarctica and the relationships they have with the abiotic environment were analyzed in situ, in order to characterize the microecosystems integrating these lichens, from a microecological perspective. Mycobiont and photobiont cells, the majority classified as living by fluorescent vitality testing, were observed distributed through the fissures of the granite. The fact that extracellular polymeric substances were commonly observed close to these cells and the features of these compounds, suggest a certain protective role for these substances against the harsh environmental conditions. Different chemical, physical and biological relationships take place within the endolithic biofilms where the lichens are found, possibly affecting the survival and distribution of these organisms. The alteration of bedrock minerals and synthesis of biominerals in the proximity of these lichens give rise to different chemical microenvironments and suggest their participation in mineral nutrient cycling

Lichens in Forest Park and Nitrogenous Air Pollution

Lichens have been shown to be useful bioindicators for determining levels of nitrogen deposition related to air pollution. Preliminary lichen surveys in Forest Park in 2011 and 2012 revealed the presence of lichen species associated with high levels of nitrogenous pollution. The summer of 2013, we conducted lichen surveys at 25 permanent research sites that had been set up in Forest Park and the Ancient Forest Preserve in 1993. The majority of the lichens we collected at every site were classified as indicative of worst, poor, or fair air quality, with few lichens found that would indicate good or best air quality. Lobaria is a lichen common in Oregon and is important in the normal nitrogen cycle in forests. However, Lobaria is very sensitive to nitrogenous air pollution and is associated with the best air quality category. We only collected Lobaria at one site in the middle of the park. We found no significant differences in lichens in the different air quality variables in the various sections of the park, indicating that all of Forest Park is subjected to poor air quality

100 years of tropical bryophyte and lichen ecology : a bibliographic guide to the literature from 1901 - 2000

A list of 401 citations pertaining to the ecology of tropical bryophytes and lichens is presented. The bibliography includes publications addressing the biology, ecology, natural history, and physiology of bryophytes and lichens, but generally eschews taxonomic and floristic papers. All citations have been verified, unless denoted with an asterisk (*). An appendix that groups citations by category is provided

Ecology and conservation of bryophytes and lichens on Fagus sylvatica

Environmental factors related to the occurrence of epiphytic bryophytes and lichens were examined in beech (Fagus sylvatica) forests in the Province of Halland, Sweden. Patterns in species composition and species number at different temporal and spatial scales were analyzed with emphasis on species of conservation concern (i.e. red-listed and indicator species). (I) At stand level, the availability of substrate, a high stand age and forest continuity were the most important factors explaining high species number of epiphytes of conservation concern. The difference in species number between stands with and without forest continuity was probably related to the presence of old trees and the time available for species colonization. (II) Within stands, plots containing old trees, at the base of slopes and with low recent forestry impact had the highest species number. At tree level, age, size and moss cover were primary factors in explaining both species number and species composition of all species. Red-listed lichens were associated with damaged beech trees older than 180 years, whereas the few red-listed bryophytes were also recorded on younger stems in dense stands. (III) The vertical distribution of epiphytes, recorded on newly fallen beech stems, could also be related to tree age. Some red-listed lichens were recorded only from above 2 m in height on trees older than 250 years. The presence of any species of conservation concern at 2-5 m height on standing living beech trees correlated positively to moss cover and bark structure, which in turn was dependent on tree age. (IV) The effect of bark and tree characteristics on species occurrence was studied. It was found that the combination of high bark pH, high tree age and damaged stem best explained the number of species of conservation concern. The link between old beech trees and high bark pH was partly explained by a positive effect of tree age on stemflow pH. (V) At microhabitat level, the type of stem damage rot hole was found to positively influence bark pH and the occurrence of species of conservation concern. Old and slow-growing trees with rot holes are, however, often removed from managed beech forests. A spatial separation between managed and retention areas is therefore recommended in shelterwood forestry

Lichens: might be considered as a source of gastroprotective molecules?

Indexación: Web of Science; ScieloABSTRACT Lichens are symbiotic relationship between fungi and algae or cyanobacteria. Secondary metabolites from lichens are known as lichen substances. We investigated depsidone and depside from lichens 1-6 in the context of their action to prevent gastric ulcer on the model of HCl/ethanol in mice for the first time. Doses of 30 mg/kg of lichen substances 1-6 and positive control (lansoprazole) significantly diminished the lesion index compared with negative control (treated only with HCl/EtOH). Lobaric acid 1, atranorin 2 and psoromic acid 5 reduced the gastric lesions by 76%, 63% and 65%, while for variolaric acid 3, diffractaic acid 4 and perlatolic acid 6 their values were 32%, 14% and 45%, respectively. Our results suggest that lichens have potential as a suite of gastroprotective molecules. Keywords: Lichens; depside; depsidone; gastric ulcer;http://ref.scielo.org/6949f

Reproduction and Dispersal of Biological Soil Crust Organisms

Biological soil crusts (BSCs) consist of a diverse and highly integrated community of organisms that effectively colonize and collectively stabilize soil surfaces. BSCs vary in terms of soil chemistry and texture as well as the environmental parameters that combine to support unique combinations of organisms—including cyanobacteria dominated, lichen-dominated, and bryophyte-dominated crusts. The list of organismal groups that make up BSC communities in various and unique combinations include—free living, lichenized, and mycorrhizal fungi, chemoheterotrophic bacteria, cyanobacteria, diazotrophic bacteria and archaea, eukaryotic algae, and bryophytes. The various BSC organismal groups demonstrate several common characteristics including—desiccation and extreme temperature tolerance, production of various soil binding chemistries, a near exclusive dependency on asexual reproduction, a pattern of aerial dispersal over impressive distances, and a universal vulnerability to a wide range of human-related perturbations. With this publication, we provide literature-based insights as to how each organismal group contributes to the formation and maintenance of the structural and functional attributes of BSCs, how they reproduce, and how they are dispersed. We also emphasize the importance of effective application of molecular and microenvironment sampling and assessment tools in order to provide cogent and essential answers that will allow scientists and land managers to better understand and manage the biodiversity and functional relationships of soil crust communities

Lichens Mentioned by Pedanios Dioscorides

Lichens are included in the classification system of fungi and have been used in medicine, pharmacy and industry from antiquity to present day in the treatment of various diseases. In this study, Peri Hyles Iatrikes of Dioscorides has been investigated and evaluated from lichenological point of view. It is found that, Dioscorides mentions about medical properties and uses of probable Parmelia species such as P. saxatilis (L.) Ach or P. sulcata Taylor

Mediterranean lichens in the tropics : lichens of the mist oasis of Erkwit, Sudan

From the mist oasis of Erkwit (Red Sea coastal plain of Sudan) 25 epiphytic lichen taxa are reported, probably the first lichen floristic report for the country. Most species encountered are widespread in warm and dry areas worldwide, while a few have their center in the Mediterranean region and document a Mediterranean element in this tropical region