Abstract: Epiphytic lichen biomass accumulates slowly in forest canopies. We eval- uated three alternative hypotheses for the slow accumulation of epiphytic lichens, using two experiments in tree crowns from 15 Douglas-fir forest stands representing three age classes: old growth, young, and recent clearcuts. The first experiment evaluated whether forest age, bark roughness, or dispersal rate limits the establishment of the dominant old- growth-associated lichen, Lobaria oregana. Surface-sterilized branches with either rough or smooth bark were repeatedly inoculated with propagules and compared 1 yr after the last inoculation. Dispersal affected rates of establishment: inoculated branches had 27X more newly established thalli than controls. Establishment on smooth bark was highest in clearcuts, intermediate in young forests, and lowest in old growth. There was as much or more establishment of sown propagules on smooth-barked branches as on rough-barked branches in all age classes. In the second, transplant-performance experiment, Lobaria oregana grew as rapidly in young forests as in old growth but lost biomass and suffered more injuries in clearcuts. In contrast, L. pulmonaria performed at least as well in clearcuts as in young forests and old growth. Poor dispersal and establishment limit the development of L. oregana populations in Douglas-fir forests. Particular substrates and microenviron- ments found only in old growth are not essential for Lobaria establishment and growth. Maximizing the number and dispersion of remnant trees in cutting units should maximize the rate of accumulation of L. oregana biomass in the regenerating forest. The single most important action promoting the accumulation of old-growth-associated epiphytes will be the retention of propagule sources in and near all cutting units.

Abstract: Peltigera (Peltigerineae, lichenized Ascomycota) is one of the most widespread lichen genera incorporating bi‐ and trimembered associations involving fungi, green algae (cf. Coccomyxa), and cyanobacteria (cf. Nostoc). A wide range of morphological and chemical (secondary compounds) variation at both the intra‐ and interspecific levels is present in this genus. Compared to many other genera of macrolichens, its taxonomy, including chemotaxonomy, still remains poorly understood. Existing infrageneric classifications of Peltigera are almost exclusively based on photobiont composition of the thallus. These classifications assumed that bi‐ and trimembered taxa were distinct monophyletic entities. The genus Peltigera has never been the focus of a comprehensive phylogenetic study. The most recent and widely accepted subdivision of the genus into seven groups is based mainly on morphological and chemical characters. Relationships among species of Peltigera are investigated here using chemical, morphological, and ...

Abstract: We investigated whether dispersal limitation is an important factor for the low abundance of epiphytic lichens in young boreal forests. The number of lichen thalli on branch sections of Pinus sylvestris was counted in five second-growth stands (35-78 years old) at increasing distances (10 m, 50 m, and 100 m) from adjacent old-growth stands (122-298 years old) presumed to function as propagule sources. The number of thalli displayed a pronounced decrease with increasing distance from the old growth in both foliose and pendulous fruticose lichens. The effect of distance was statistically significant in five out of six groups of lichens. The number of thalli at 100 m constituted 22% (Parmelia sulcata) to 61% (Vulpicida pinastri) of the number found near the forest edge (10 m). In the two most abundant groups, Bryoria (fruticose) and Hypogymnia (foliose), there was close to 50% reduction in thallus numbers. The thallus size distribution of both Bryoria and Hypogymnia was strongly skewed towards small ...

Abstract: The terrestrial vegetation in Antarctica is restricted to small, very isolated, ice-free areas on the continent and on the islands adjacent to the Peninsula region. Lichens, a symbiosis between a fungus and an alga or cyanobacterium, form the most prominent component in the vegetation. They have the greatest number of species compared with other cryptogamic and unicellular organisms. They are able to colonize all types of solid substrata and have a low mineral nutrient demand. Their physiological vigour is derived from high freezing tolerance and the ability to be photosynthetically activated by water vapour uptake from snow at temperatures as low as c. -20°C. Long-term monitoring in their natural habitats demonstrates that lichens are photosynthetically active at suboptimal temperatures. Locally, however, they can benefit from meltwater on insolated rocks, but only for short periods in early summer. Although at this time they may be exposed to substrate temperatures of > 20°C and strong light they do not suffer from photostress. If, in winter, lichens are covered and kept dark by snow with temperatures close to 0°C, lichens enter a negative carbon balance. This effect may be relevant to lichens under conditions of global or regional warming.

Abstract: The objective of this paper was to determine whether CO 2 exchange rates could be used as an indicator for determining the state of development and species or functional composition of biological soil crusts in different successional stages. We quantified the CO 2 exchange rates, i.e., CO 2 assimilation and respiration, in samples from different microhabitats at two different sites in the Negev desert. In the successional pathway of the crust communities, the pioneers in colonising the soil surface are the cyanobacteria; green algae, mosses and lichens then follow. Physical influences such as soil structure and types, radiation intensity, and topographic traits such as slope directions that affect water availability and soil moisture, influence the successional pathways and the soil crust community. When physical conditions are the same, disturbances are key factors for a specific successional stage. We found a substantial gradient of CO 2 exchange at the Nizzana site for both respiration and photosynthesis. Samples from the sand dunes at the Nizzana site showed a pronounced activity gradient with high rates for assimilation (around 70 μmol CO 2 m −2 min −1 ) as well as respiration (60–70 μmol CO 2 m −2 min −1 ) at the base of dunes, decreasing towards the top. The soil crust samples of the Negev desert show comparable values. Hence, as ecotypes containing such biological soil crusts with dominant photosynthetically active organisms are a widespread phenomenon in desert, boreal and arctic systems, their contribution to the global cycling of trace gases and elements can be significant for global budgets.

Abstract: Old conifer forests in the Pacific Northwest have a wide range of microhabitats induced by canopy structure and substrate characteristics. We used the Wind River Canopy Crane to sample lichens and bryophytes throughout the spectrum of habitats available to epiphytes. Of the 111 species found in 72 sample units, 97 were lichens and 14 were bryophytes. Epiphyte communities showed marked variation with respect to height in the canopy, bark vs. wood, degree of sheltering, and stem diameter. Of these factors, height in the canopy was most strongly related to epiphyte communities. Furthermore, the top two meters of the tallest trees hosted a diverse assemblage of both rare species (Tholurna dissimilis) and weedy, nitrophilous species (Candelaria concolor, Hypogymnia tubulosa, Parmelia sulcata), presumably induced by birds delivering lichen propagules and nutrients. Ten species were more frequent on bare wood than bark, including Ophioparma rubricosa, Letharia vulpina, Placynthiella spp., Ptychographa x...

Abstract: Relations between irradiance (I) and lichen growth were investigated for five macro-lichens growing at two sites in Sweden. The lichens represented different mycobiont–photobiont associations, two morphologies (foliose, fruticose) and two life forms (epiphytic, terricolous). The lichens were transplanted at two geographically distant sites in Sweden (1000 km apart) from Sept 1995 to Sept 1996 in their typical microhabitats, where microclimate and growth were followed. Between April/May and Sept 96, the terricolous species had a dry matter gain of 0·2 to 0·4 g (g DW)–1 and the epiphytes 0·01 to 0·02 g (g DW)–1. When related to area, growth amounted to 30 to 70 g m−2 for the terricolous species and to 1 to 4 g m−2 for the epiphytes. There was a strong correlation between growth and intercepted irradiance when the lichens were wet (Iwet), with 0·2 to 1·1 g lichen dry matter being produced per MJ solar energy. Across the 10 sets of transplants, light use efficiencies of dry matter yield (e) ranged between 0·5 and 2%, using an energy equivalent of 17·5 kJ g−1 of lichen dry matter. The higher productivity of the terricolous species was due to longer periods with thallus water contents sufficient for metabolic activity and because of the higher mean photon flux densities of their microhabitat. A four-fold difference in photosynthetic capacity among the species was also important. It is concluded that lichen dry matter gain was primarily related to net carbon gain during metabolically active periods, which was determined by light duration, photon flux density and photosynthetic capacity.

Abstract: The lichen woodland is one of the most important forest ecosystems in North America, dominating the cen- tral part of the boreal forest. The southernmost lichen woodland is paradoxically in the heart of the southern boreal forest. This distribution prompted this study aiming to identify the factors responsible for the inception and develop - ment of the lichen woodland at its southern range limit in eastern Canada. We tested the hypothesis that the southern lichen-spruce woodland is a regressive, post-fire type of the spruce-moss forest. We studied adjacent lichen-spruce and spruce-moss stands growing under similar soil conditions. We reconstructed the recent history of spruce-moss forest transformation to lichen woodland using tree size, tree ring patterns, and macrofossil analysis of organic soil. All the plant macrofossils buried in the unburned organic mat below the charcoal layer of the last fire corresponded to a feather-moss forest assemblage and included head capsules of the spruce budworm (Choristoneura fumiferana(Clem.)) or European spruce sawfly (Gilpinia hercyniae Hartig.). The impact of combined insect and fire disturbances translates into a dramatic decrease in post-fire tree regeneration of the forest inducing the shift to lichen woodland. The inception of the southern lichen woodland highlights the fragility of the spruce-moss forest even in the core area of the southern commercial boreal forest.

Abstract: Many studies have shown that certain species of bryophytes and lichens require old-growth forests for their survival. The objective of this study is to evaluate the composition and diversity of epiphytic lichen and bryophyte communities on trembling aspen (Populus tremuloides), as a function of the time elapsed since stand initiation. The study was carried out in the forests surrounding Lake Duparquet, in the southwestern part of Quebec's boreal forest. Stands representing different post-fire successional stages, corresponding to 278, 125, 79, and 51 yr since the last fire were selected. For each stand age, 10 trees from four different sites were sampled. A total of 75 species of non-vascular plants were found, including 34 species of mosses, seven species of liverworts, and 34 species of lichens. More species were observed in the 278-yr old stand, which also contained a greater number of exclusive species. In a correspondence analysis performed on species presence/absence data, axes one and two ...

Abstract: Lichen species in the genera Cladonia (subgenus Cladina), Cetraria, Stereocaulon and Alectoria are important vegetation components on well-drained terrain and on elevated micro-sites in peatlands in boreal-Arctic regions. These lichens often form closed mats, the component thalli in which grow vertically upwards at the apices and die off in the older basal regions; they are therefore only loosely attached to the underlying soil. This growth habit is relatively unusual in lichens being found in <0.5% of known species. It might facilitate internal nutrienr recycling and higher growth rates and, together with the production of allelochemicals, it might underlie the considerable ecological success of mat-forming lichens; experiments to critically assess the importance of these processes are required. Mat-forming lichens can constitute in excess of 60% of the winter food intake of caribou and reindeer. Accordingly there is a pressing need for data on lichen growth rates, measured as mass increment, in order to help determine the carrying capacity of winter ranges for rhese herbivores and to better predict recovery rates following grazing. Trampling during the snow-free season fragments lichen thalli; mat-forming lichens regenerate very successfully from thallus fragments provided trampling does nor re-occur. Frequent recurrence of trampling creates disturbed habitats from which lichens will rapidly become eliminated consistent with J.P. Grime's CSR strategy theory. Such damage to lichen ground cover has occurred where reindeer or caribou are unable to migrate away from their winter range such as on small islands or where political boundaries have been fenced; it can also occur on summer range that contains a significant lichen component and on winter range where numbers of migrarory animals become excessive. Species of Stereocaulon, and other genera that contain cyanobacteria (most notably Peltigera and Nephroma), are among the principal agents of nitrogen fixation in boreal-arctic regions. Stereocaulon-dominated subarctic woodlands provide excellent model systems in which to investigate the role of lichens in nitrogen cycling. Mat-forming lichens are sensitive indicators of atmospheric deposition partly because they occur in open situations in which they intercept precipitation and particulates directly with minimal modification by vascular plant overstoreys. Data from both the UK and northern Russia are presented to illustrate geographical relationships between lichen chemistry and atmospheric deposition of nitrogen and acidity. The ecology of mat-fotming lichens remains under-researched and good opportunities exist for making significant contributions to this field including areas that relate directly to the management of arctic ungulates.

Abstract: We have investigated whether DNA extraction protocols designed specifically for fungi and/or lichens perform better on lichens than do corresponding protocols designed for plants and insects Two different PCR-amplification protocols were used to evaluate the quality of the DNA extracted with each method The DNA extractions with highest quality were obtained with the protocols designed for insects and plants, and the most successful amplifications were obtained with Ready-To-Go PCR Beads This indicates that fungal or lichen specific protocols might not be necessary for successful extraction of high quality DNA from lichens

Abstract: Patterns of photobiont diversity were examined in some Nostoc-containing lichens using the nucleotide sequence of the cyanobacterial tRNALeu (UAA) intron. Lichen specimens collected in northwestern USA were analysed and the sequence data were compared with tRNALeu(UAA) intron sequences previously obtained from lichens in northern Europe. Generally, it is the species identity of a lichen rather than the geographical origin of the specimen that determines the identity of the cyanobiont. Identical intron sequences were found in Peltigera membranacea specimens collected in Oregon (USA) and in Sweden, and very similar sequences were also found in Nephroma resupinatum thalli collected in Oregon and Finland. Furthermore, in mixed assemblages where two Peltigera species grew in physical contact with each other, the different lichen species housed different photobiont strains. There is however not a one-to-one relation between mycobiont and photobiont as some intron sequences were found in more than one lichen species, and different intron sequences were found in different samples of some lichen taxa. Peltigera venosa exhibited a higher level of photobiont diversity than any other lichen species studied, and several intron sequences could for the first time be obtained from a single thallus. It is not clear whether this is evidence of lower cyanobiont specificity, or reflects an ability to exhibit different degrees of lichenization with different Nostoc strains. In one specimen of P. venosa, which contained bipartite cyanosymbiodemes and tripartite, cephalodiate thalli, both thallus types contained the same intron sequence.

Abstract: Levels of total arsenic and arsenic species were determined in fungi collected from Yellowknife, NWT, Canada, an area that has been affected by past mining activities and elevated arsenic levels. Lichens (belonging to Cladonia and Cladina genera), as well as the mushrooms Coprinus comatus, Paxillus involutus, Psathyrella candolleana and Leccinum scabrum, were studied for the first time. Most of the fungi contained elevated arsenic levels with respect to data found in the literature for background levels. Minor amounts of arsenobetaine were found in all lichen samples. The major water-soluble arsenic species in the fungi were inorganic arsenic for lichens and Psathyrella candolleana, arsenobetaine for Lycoperdon pyriforme and Coprinus comatus, and dimethylarsenate for Paxillus involutus and Leccinum scabrum. A large proportion of water-soluble arsenic in Paxillus involutus occurred as an unknown compound, which did not co-chromatograph with any of the available standard arsenic compounds. Low proportions of water-soluble arsenic species (made evident by low extraction efficiencies) were observed in the majority of fungi studied. Arsenic that is not extracted may be bound to lipids, cell components or proteins, or might exist on the surface of the fungus as minerals. Copyright © 2000 John Wiley & Sons, Ltd.

Abstract: We conducted field experiments manipulating lichens, shrubs, and herbs along a time-since-fire gradient and assessing effects on three endemic herbaceous species of Florida scrub: Eryngium cuneifolium, Hypericum cumulicola, and Polygonella basiramia. Responses included seed germination, survival, biomass, and fecundity. Transplants into recently burned patches generally had higher survival, larger biomass, and greater reproductive output than transplants into long-unburned patches. Open areas and sites near oaks frequently were more favorable than sites near Florida rosemary. Ground lichens did not affect germination but increased mortality rate of seedlings. Neighboring small shrubby and herbaceous species did not affect the performance of these species. Of the three species, naturally occurring E. cuneifolium were farthest from large shrubs, and their microhabitats had the least ground lichens and shrubs. Eryngium cuneifolium and H. cumulicola are capable of forming persistent seed banks and their recruitment after fire depends mostly on these dormant seeds. Polygonella basiramia relies on seed dispersal and immediate seed germination to colonize recently burned patches. Management for these species should involve variable fire regimes to allow all three species to persist along with many other scrub endemics.

Abstract: A grass endemic to Mexico, Sporobolus atrovirens, was identified for the first time as a desiccation-tolerant resurrection plant. Nine species of desiccation-tolerant vascular plants were found in the highland area of Mexico, including four species of ferns (Cheilanthes and Pellaea species) and three species of Selaginella. Two other grasses collected were known desiccation-tolerant species distributed from South America (Cordoba) to North America (Georgia). The ferns Ch. bonariensis, Ch. integerrima, Ch. myriophylla and P. sagittata are newly reported as desiccation-tolerant plants. The osmoprotectant trehalose which has been recorded as rare in plants was found in air-dry foliage of representative species of widely different taxa (9–291 µM g–1 dry weight). The flora of desiccation-tolerant species in Mexico is discussed in connection with its ability to accumulate trehalose.

Abstract: As part of Project Surumoni, an investigation was conducted in 1997-1998 on species diversity and vertical distribution of lichenized fungi within a tropical lowland rain forest in southern Venezuela. A tower crane at Surumoni, which gives easy access to all forest strata, facilitated the investigation. In the plot, nine trees were selected as phorophytes on which 250 species of lichenized fungi were observed. Study results showed crustose lichens as the dominant life form. Of these, Thelotremataceae, Graphidaceae, and Trypetheliaceae contributed to nearly three quarters of total species richness. The species spectrum showed a well-defined vertical stratification from forest floor to top of canopy. At ground level, shade- tolerant species (chiefly Thelotremataceae) occurred. Moving upward, the proportion of Graphidaceae and Trypetheliaceae increased continuously, but Thelotremataceae appeared to remain constant up to the inner canopy. Higher yet, Thelotremataceae were less frequent, with Graphidaceae and Trypetheliaceae domi- nating. The degree of species turnover along the vertical gradient is shown in several diagrams for trees of stratum A and B separately. Species replacement is highest between height zones 1 and 2 for investigated trees of stratum A, but the more uniformly barked trees of stratum B do not show this marked difference. Calculation of additive beta turnover reveals, depending on substratum, three to nearly four complete species turnovers along the vertical gradient in the forest.

Abstract: The epiphytic lichens around limestone and sandstone quarries were investigated in northern Greece and central Italy to study the effect of alkaline and acid dust on epiphytic lichen vegetation in the Mediterranean area. The results showed that the main factor influencing the diversity of the epiphytic lichen vegetation studied is the distance from quarries, and that the chemistry of dust is not an important parameter. The fact that all but a few resistant lichen species die when subjected to high dust concentrations suggests that epiphytic lichens could be usefully employed for monitoring dust fallout and the effects of dust contamination.

Abstract: We examined the dynamics of cryptogamic soil crusts in a derived (disclimax) grassland near Orange in south-eastern Australia. Changes in the cover of cryptogamic crusts and floristics and abundance of the constituent species were measured on four treatments with two levels each of grazing and cultivation. Twenty-two lichens, mosses and liverworts were found at the study site and, of these, 13 were collected in the quadrats. Three moss species (Barbula calycina, Eccremidium arcuatum and Bryum pachytheca) and one lichen species (Cladonia tessalata) accounted for 67% of total cover-abundance scores. Generally, cover-abundance was significantly higher in the unvegetated microsites than in the vegetated microsites. Species richness was not significantly different between the four grazing-cultivation treatments but, on average, there were significantly more species in the unvegetated microsites (mean = 3.2 species) than in the vegetated microsites (0.54 species). Grazing and cultivation resulted in significantly greater cover of bare ground and consequently significantly greater crust cover. Averaged across all treatments, approximately half of the area of unvegetated soil was occupied by cryptogams. Overall, the results indicate that lichens and bryophytes are important components of derived temperate grasslands, surviving in even densely vegetated swards. This study suggests that strategies which disturb the soil surface (e.g. grazing and cultivation) will stimulate the abundance and cover of soil crust organisms by increasing the availability of unvegetated microsites.

Abstract: The patterns of cover and species diversity (richness and composition) of macro-lichens, bryophytes, and vascular plants are described for a Canadian montane forest in an area where the forest is highly valued both for wood production and for the terrestrial lichen that is a vital part of the diet of the endangered woodland caribou (Rangifer tarandus caribou Gmelin). In 180, 6.5 m × 6.5 m plots placed in nine stands within a 375 km2 area, we found lichens were abundant, but the ground layer was dominated by feather moss. Mean species richness at the plot level for lichens (23) is about double that of bryophytes (13) and vascular plants (11). Differences in species composition are small with any two plots having in common at least 50% of their vascular plants, 60% of their bryophytes, and 70% of their lichens. Comparisons of 10% of the most open with 10% of the most dense canopy plots revealed that the more open sites have greater lichen cover, higher elevation, older trees, more lichen and vascul...

Abstract: The oribatid mite assemblages found in late-glacial and early-Holocene sediments in Krakenes Lake, western Norway, consist of 38 species within 24 genera. In accordance with known present habitat distribution we distinguish 4 true aquatic species, 6 species associated with wetland, 2 with mesic grassland, 12 with dry grassland and heathland, 3 with saxicolous and arboricolous lichens, 7 widely distributed species, and 4 with uncertainly known habitat preferences. The sediments from the pioneer phase (12,300-11,700 14C BP) contain 7 species, among them the 2 typical pioneer species Limnozetes ciliatus and Tectocepheus velatus.

Abstract: This paper describes the use of epiphytic lichens as bioindicators for spatial monitoring of mercury and other elements in air near the natural gas treatment facilities at Molve, Croatia. It is well known that at this location the concentration of mercury in natural gas is very high and therefore it has to be removed from natural gas before further processing in order to prevent technological and environmental problems. In order to monitor the efficiency of an industrial facility for removal of mercury from natural gas, mercury measurements in air and lichens were performed during 9 months in 1997/1998. In situ lichens Parmelia sulcata, Xantoria parientina and Hypogymnia physodes and transplanted lichen species Hypogymnia physodes were used. A good correlation between mercury concentrations in air and lichens was found. The concentrations of barium and bromium were also significantly elevated in transplanted lichens, most probably related to technological process at the gas treatment plant and/or other geological factors. It was confirmed that lichens can successfully be used as bioindicators, provided a careful experiment is designed, particularly the amount of lichens transplanted, the duration of exposure and the initial levels and homogeneity of transplanted lichens.

Abstract: In 1995, we installed surface-sterilized, rough-barked and smooth-barked tree branches in clearcuts, young forests, and old growth. Half of the experimental branches were inoculated with propagules of the epiphytic cyanolichen, Lobaria oregana. In 1997, we concluded that L. oregana was associated with old-growth Douglas-fir forests because of dispersal limitation; addition of L. oregana propagules resulted in a marked increase in establishment rates. In 1999, we revisited the experiment to determine whether other epiphytes had colonized the tree branches. We also checked to see if the 1997 results of the experiment persisted. A total of 26 epiphyte genera (nine bryophytes and 17 lichens) had colonized the branches. Lichen colonization was generally fastest in clearcuts. Colonization by alectorioid lichens was rapid in both clearcuts and old growth but slow in young forests. In contrast, bryophyte colonization was relatively rapid in all age classes. Epiphyte colonization was generally more rapid ...

Abstract: The internal transcribed spacers (ITS1 and ITS2), and the 5.8S region of the nuclear ribosomal DNA were sequenced for 52 specimens representing 35, mosdy foliose, taxa of the lichen family Physciac...

Abstract: A total of 201 different lichen species were identified from 105 sampling stations in the Turkish provinces of Artvin, Erzurum, and Kars. Among these, 25 species were new records for the lichen flora of Turkey.

Abstract: Lichen-forming fungi can occur on river and lake margins subjected to varying water levels, and on tidal coastal rocks where they can constitute major components of the biota. There are approximately 700 species known from coastal rocks and 200 from freshwater river and lake margins. Most cannot survive constant immersion although there are exceptions. Some species are only exposed at the lowest tides or when there are exceptional droughts. Vertical zonations of lichens are characteristic of freshwater and marine habitats. The heights of zones vary according to the degree of exposure and periods of inundation. Measurements of these zones can be of value in assessments of risks due to storms and of river channel capacity. Attention is also drawn to mycophycobioses in freshwater as well as maritime situations. Most work on coastal and freshwater lichens has been in temperate regions. In the tropics lichens are less well developed on coastal rocks, but tropical stream margins are yielding species new to science. The ecophysiology and biology of these fungi is scarcely explored, but some key features are highlighted. Many fundamental aspects of these fascinating fungi remain uncertain, for example where different species of the same genus occur in both habitats. The systematics, ecology and physiology ofthl~se fascinating fungi merit increased attention by mycologists.