Abstract: About one-fifth of all known extant fungal species form obligate symbiotic associations with green algae, cyanobacteria or with both photobionts. These symbioses, known as lichens, are one way for fungi to meet their requirement for carbohydrates. Lichens are widely believed to have arisen independently on several occasions, accounting for the high diversity and mixed occurrence of lichenized and non-lichenized (42 and 58%, respectively) fungal species within the Ascomycota. Depending on the taxonomic classification chosen, 15-18 orders of the Ascomycota include lichen-forming taxa, and 8-11 of these orders (representing about 60% of the Ascomycota species) contain both lichenized and non-lichenized species. Here we report a phylogenetic comparative analysis of the Ascomycota, a phylum that includes greater than 98% of known lichenized fungal species. Using a Bayesian phylogenetic tree sampling methodology combined with a statistical model of trait evolution, we take into account uncertainty about the phylogenetic tree and ancestral state reconstructions. Our results show that lichens evolved earlier than believed, and that gains of lichenization have been infrequent during Ascomycota evolution, but have been followed by multiple independent losses of the lichen symbiosis. As a consequence, major Ascomycota lineages of exclusively non-lichen-forming species are derived from lichen-forming ancestors. These species include taxa with important benefits and detriments to humans, such as Penicillium and Aspergillus.

Abstract: Bacteria mycorrhizal fungi freshwater algae saltmarsh metallophytes lichens bryophytes and pteridophytes angiosperms (asteraceae, poaceae, caryophyllaceae) angiosperms (brassicaceae) aquatic macrophytes plant response to aluminium toxicity in acid soil tree crops tree bark tree rings and dendroanalysis heavy metal interactions in soils and implications to soil microbial biodiversity behaviour of heavy metals in soils.

Abstract: Extensive investigations made in the past two decades on lichen photosynthesis in relation to water content have shown two features of particular interest: first, the depression of net photosynthesis at high water contents, suprasaturation (i.e. the lichen contains more water than necessary to saturate photosynthesis), and, second, the ability of green algal lichens to regain photosynthetic activity by uptake of water from humid air. Evidence from several investigators is presented to confirm that both phenomena are now well substantiated through laboratory investigations. It has been questioned whether these features do actually occur in nature and, if they do, to what extent. Recent work is summarized that demonstrates that for many of the lichens studied suprasaturation is of major importance and can result in depressed photosynthesis for around a third of the time that the lichens are photosynthetically active. Reactivation of photosynthesis of green algal lichens by high humidity is also, apparently, very common in some environments, for example, humid temperate rainforests, occurring almost every night. It is possible that the dominance of green algal lichens, rather than cyanobacterial species, in these habitats is a result of their ability to utilize water vapour. If so, then the phenomenon must have major ecological importance for lichen productivity. In general, laboratory studies seem to be able to predict extremely well the behaviour of lichens in their natural habitat.

Abstract: In this study, we explore how Sphagnum mosses and Scots pine, Pinus sylvestris, interact on different spatial and temporal scales in a boreal bog ecosystem. We were particularly interested in relationships between the occurrence of Sphagnum-dominated habitats and the occurrence of Scots pines of different age and size. Juvenile and adult pines occurred in different habitats. While juveniles mainly occurred in Sphagnum-dominated habitats, predominantly with Sphagnum rubellum, adult pines were found in habitats dominated by lichens, or with a sparse vegetation cover. Examination of surface peat cores sampled close to adult pines revealed that almost all pines (97%) had established in a Sphagnum-dominated environment and that the habitat had changed since pine establishment. Scots pine is thus capable of changing and exterminating the Sphagnum-dominated environment preferred for germination and establishment. Pines impede Sphagnum growth and peat accumulation significantly once they have reached a stem diameter of approximately 20 mm. It takes from 30 to 90 yr for a pine to reach that size. Our results show the importance of interactions between Scots pine and Sphagnum mosses in bog ecosystems. We conclude that interactions between trees and Sphagnum mosses are important driving forces behind the vegetation change that has characterised boreal bogs during the Holocene.

Abstract: Lichen community development was examined in a postfire chronosequence from lodgepole pine (Pinus contorta Dougl. ex Loud var. latifolia Engelm.) forests in the Omineca region of north-central British Columbia and in stands originating from logging in the early 1980s. Fire-origin stands showed dense regeneration of pine and widespread growth of acrocarpous mosses such as Polytrichum spp. As canopy thinning progressed, Cladonia spp. lichens initiated development at the forest floor surface. By 50–100 years after stand origin, Cladina mitis and Cladina rangiferina dominated at the forest floor surface, remaining at high cover values well into the second century of stand development. Late seral stages of stand development (approximately 150+ years) showed increasing basal area and canopy cover of lodgepole pine, with feathermoss mats (e.g., Pleurozium schreberi) replacing terrestrial lichens at the forest floor surface. Stand ordinations confirmed these groupings of species. Stand structural factors that cor...

Abstract: Sequestrate fungi are a polyphyletic, diverse group of macrofungi with truffle-like, underground (hypogeous) or emergent fruit bodies, which are well represented in Australia and New Zealand. The first species in the region were described in 1844, but sequestrate fungi have been poorly documented until recent times. Regional diversity of sequestrate fungi is high in comparison to other parts of the world: for ascomycetes and basidiomycetes 83 genera and 294 species are currently known in Australia and 32 genera and 58 species in New Zealand. Only an estimated 12–23% of species are known for Australia and 25–30% for New Zealand. On that basis, between 1278–2450 species may occur in Australia and 193–232 in New Zealand. Centres of diversity for some groups of sequestrate fungi occur in the region, e.g. Russulaceae (five known genera, 68 species) and Cortinariaceae (eight genera, 33 species). Some other groups are less diverse than in the northern hemisphere, e.g. sequestrate Boletaceae (seven genera, 25 species). More than 35% of Australian sequestrate genera and 95% of species are endemic; for New Zealand about 45% of sequestrate genera and 80% of species are endemic. Australia and New Zealand share similarities in sequestrate fungi at generic level (11% of total) but do not share many of the same species (4% of total). Knowledge of biogeographical distributions is limited by incomplete taxonomic knowledge and insufficient collections. Some Gondwanan, Australasian and widespread/cosmopolitan patterns are evident. Some exotic sequestrate fungi have been recently introduced and some fungi indigenous to the region occur world-wide as exotics with eucalypt plantings. Within Australia and New Zealand, there is evidence that characteristic suites of fungi co-occur in different climatic and vegetation types. Mycorrhizas of Australian and New Zealand taxa have a range of morphological and physiological attributes relating to their effect on plants and broader roles in ecosystem nutrient cycling and health. Spores of sequestrate fungi are dispersed by a range of fauna. There are tripartite inter-dependent interactions between mycorrhizal plants, sequestrate fungi and native mammals and birds that use the fungi as food. Major environmental influences affecting the distribution, diversity and abundance of sequestrate fungi include climate, topography, soil, vegetation and animals. Imposed upon such influences are a range of natural and human-induced disturbance factors which alter habitat heterogeneity, e.g. fire, fragmentation and replacement of native vegetation and exotic organisms. Rare and endangered sequestrate fungi are likely to occur in Australia and New Zealand, but for most taxa there is insufficient data to determine rarity or commonality. In the face of poor knowledge, assemblage-based and habitat-based approaches are the most appropriate for conservation and management of sequestrate fungi. Habitat heterogeneity may be important for the fungi at scales ranging from different climatic and vegetation types to local topographic-related variations.

Abstract: Pine-lichen woodlands in north-central British Columbia show a long period of successional development where reindeer lichens (Cladina spp.) dominate plant cover at the forest floor surface. However, in mid- to late-successional stands lichen cover is replaced in a mosiac of surface microsites by feather moss mats (largely Pleurozium schreberi), with moss mats often burying lichen mats that previously had occupied these microsites. We have compared moss and lichen dominated microsites at this stage of stand development, looking at the influence of canopy structural variables and development of forest floor plant communities on microsite expression. Microsites with high feather moss mat cover had greater canopy leaf area index values, compared to microsites where lichen cover predominated. Leaf area index values were highly correlated with stand level structural variables, including basal area, total volume, and biomass of the dominant canopy tree species Pinus contorta. Changes in stand architecture were further associated with the accumulation of litter and organic matter at the forest floor surface. These factors suggest that the manipulation of stand structure in managed forests, for instance through partial-cut harvesting, may delay successional changes and promote continued lichen growth in these forest types. This is an important consideration in the management of pine-stands in northern B.C., where lichen mats provide significant forage values for caribou populations.

Abstract: Current forestry policies worldwide aim at conserving and restoring biodiversity in managed forests. In this respect, epiphytic lichens have become a focal group in studies of how logging and silvicultural methods can be adjusted to mimic and restore old-growth conditions. We addressed this issue in a retrospective study in the coastal spruce (Picea abies) forest region of central Norway, surveying 31 old forest sites in order to relate a selected group of epiphytic macrolichens (Fuscopannaria ahlneri, Lobaria pulmonaria, L. scrobiculata, Nephroma spp., Platismatia norvegica, Pseudocyphellaria crocata, Ramalina thrausta, and Sphaerophorus globosus) to forest stand characteristics and previous logging history. The lichens were associated with brook ravines, F. ahlneri and P. crocata mostly so, being 10 times more abundant in ravine valley bottoms than on adjacent slopes and plateaus. All species used spruce trees as their main substrate, but L. pulmonaria, L. scrobiculata, and Nephroma spp. preferred scatt...

Abstract: Microbial populations play a critical role in the regulation of nutrient cycling and energy flow in ecosystems, as they mediate decomposition and subsequent mineralization rates which, in turn, regulate nutrient availability and primary production (Zak and Freckman 1991). Even in regions where water is considered limiting, nutrient availability can restrict plant growth (Romney et al. 1978). Extreme temperatures and/or low soil moisture restrict soil food web development. As soil favorability increases, edaphic taxa generally appear in the following order: pigmented bacteria > actinomycetes > algae and cyanobacteria > fungi, protozoa, other bacteria > lichens > mosses and microarthropods (Cameron et al. 1970).

Abstract: We studied the effects of Svalbard reindeer on the abundance of lichens in Spitsbergen. A survey was carried out in 14 areas with contrasting reindeer densities. Separate cover estimates for crustose, fructose and foliose lichens were taken in each area, and related to the density of reindeer pellet groups, a measure of reindeer density. Dominant macrolichen families were identified in 10 areas, and a full record of macrolichen species was taken in four additional areas. Varia- tion in reindeer density is partially due to past overhunting, and subsequent incomplete recovery, releasing some areas from reindeer grazing for 100-200 yr. The cover of fruticose lichens was negatively related to reindeer pellet group density, indicating suppression by Svalbard reindeer. This makes their impact comparable to other members of the Rangifer genus around the northern hemisphere. The generally recorded low abundance of lichens in the diet of Svalbard reindeer compared to other Rangifer species, therefore, was interpreted as the depletion of fruticose lichens in Spitsbergen, and a subsequent switch to alternative foods. Of all fruticose lichens, Stereocaulon spp. appeared least sensitive to grazing. Crustose and foliose lichen cover was independent of reindeer pellet group density. The cover of crustose lichens was significantly related to latitude, with greater cover in more northern areas. Foliose lichens were more abundant in places where moss cover was high. We conclude that the impact of Svalbard reindeer on lichens is dependent on growth form, with fruticose lichens suffering from grazing, whereas foliose lichens might indirectly benefit from higher densities of reindeer or, like crustose lichens, be controlled by other factors.

Abstract: Lichens are unique and fascinating symbiotic organisms. They have been studied for more than two centuries as morphological entities, although their fungal-algal composition (symbiosis) was only recognized in 1869 by Schwendener. The discovery of the symbiotic "double" nature of lichens led to a controversy among scientists of the late 19th century. To some extent the discussion of whether lichens should be considered as whole or composite plants initiated trials to separate the symbiotic partners, fungus and alga, in order to obtain scientific proof of the composed morphologies of diverse lichens. These early experiments to separate and recombine lichen symbionts can be considered as the "birth" of "experimental lichenology." As most of the early manipulations with lichen bionts and whole lichens did not have the expected success to reconstitute a fully developed thallus from its components (resynthesis) or to grow whole lichen thalli in culture, experimental lichenology remained a nearly unexplored scientific field for many decades. However, successful culture and resynthesis experiments that were performed during the pioneer period (e.g., Bonnier 1887, 1889; Stahl 1877) were ignored and overlooked. Finally, the composite and symbiotic nature of lichens was accepted by most lichenologists; mainly by successful isolations of the algal partners, which were identified as typical representatives of green algae and/or blue-green algae, recently named cyanobacteria. Additionally, an exceptional work of culturing lichens was presented by Thomas (1939), who cultured different mycobionts under various physiological conditions and temperature regimes. Moreover, Thomas reported the first successful resynthesis of Cladonia pyxidata. The early work on the culture of Endocarpon pusillum by Stahl (1877) and Geitler (1938) and Cladonia by Thomas (1939) was partly reproduced and completed by Ahmadjian and Heikkili (1970) and Bertsch and Butin (1967), Stocker-W6rgt6tter and Tuirk (1988), and Wagner and Letrouit-Galinou (1988). Since the 1970's, the improvement and optimization of culture conditions of lichen-forming fungi have been a major goal of experimental lichenology. A modern approach to improvement of culture conditions, adapting microbiological methods for lichens, was presented by Ahmadjian (1973). In his contribution "Methods for isolating lichen mycoand photobionts," Ahmadjian introduced a manual on how tools and nutrient media can be prepared for the isolation and culture of lichen symbionts. It was postulated by Ahmadjian that the best units for mycobiont isolations are spores, because they represent the "true" lichen fungus and should show relatively low contamination compared with hyphae obtained from the thallus pieces that may contain a variety of micro-organisms like bacteria, epiphytic algae, and fungi. Further methods for the culture of lichen symbionts were also presented by Bubrick (1988). Spore isolations became very popular among lichenologists and had strong influence on experimental lichenology during the following 20 years Highly time consuming efforts were initiated to grow lichens and mycobionts from single spores (e.g., Ahmadjian & Jacobs 1981; Culberson et al. 1992; Honegger & Kutasi 1990; Stocker-Wirg6tter & TUrk 1989a). These single spore isolations provided mycobiont cultures with a decreased rate of contamination than polyspore isolates, but only low quantities of lichen material were harvested after long incubation periods of up to 2-3 yr. Several of those efforts were done by lichen chemists (e.g., Culberson et al. 1992; Leuckert et al. 1990) and focussed on the production of lichen substances by spore-derived cultures. The question of whether the production of lichen secondary compounds is a feature of the lichen fungus alone or a characteristic of the mycobiont living in symbiosis with a specific

Abstract: Biological soil crusts most often occur under harsh conditions that include extremes in temperature and light and at least periodic lack of water. They occur in almost all arid and semiarid ecoregions worldwide, and in local arid micro environments in other climates (e.g., temperate regions). Despite their widespread occurrence, comparing the biogeography and ecology of soil- crust biota and communities on a global basis is almost impossible. This is because most of the data were collected (1) using different methodologies, (2) using different taxonomic systems [e.g., using Drouet’s (1956) keys, where he combined genera], and/or (3) were focused on a single group of organisms (i.e., lichens, algae, cyanobacteria, or mosses) to the exclusion of other groups.

Abstract: The formation of the organic layer within Scandinavian forest soil started about 10000 yr ago, following the retreat of the continental ice sheet. Since then the land has been slowly rising in northern Europe and uplift still occurs on the coast of the Bothnian Bay at a rate of about 0.6-0.9 m per 100 yr. Four, 300 m long, successional gradients were studied from the shoreline to a Scots pine (Pinus sylvestris) stand with a fully developed humus layer of a few centimetres' thickness. The plantless shoreline was followed by small foredunes and dunes, characterized by Agrostis stolonifera and Leymus arenarius, respectively, and the deflation basin characterized by lichens and sparse Festuca ovina and Deschampsia flexuosa. The study sites situated in Scots pine stands of about 25 and 40 yr age were characterized by sparse dwarf shrubs, lichens and bryophytes. The amount of organic matter in soil increased along the gradient. When the microbial biomass, estimated as indicative phospholipid fatty acids (PLFAs)...

Abstract: In Australian rangelands, crusts comprise an assortment of lichens, bryophytes (mosses and liverworts), algae, cyanobacteria, and assorted bacteria and fungi (see Chap. 10). Whilst biological crusts in Australia are rather thin and occur often in association with physically or chemically crusted surfaces (Eldridge et al. 1995), they influence the flow of water through, and the movement of sediments over, the soil surface. Because of the marked differences in crust type and morphology at even small spatial scales, large differences in water flow through biological crusts often occur. It is these differences which make it difficult to generalize about the role of crusts in water flow in deserts.

Abstract: In Yunnan Province China, ethnic peoples use five species of lichens as foods (Lobaria isidiophora, L. kurokawae, L. yoshimurae, Ramalina conduplicans, and R. sinensis) and five others as health-promoting teas (Lethariella cashmeriana, L. sernanderi, L. sinensis, Thamnolia vermicularis, and I subuliformis). Local traditions concerning the use of these lichens are described, and the natural-product chemical constituents of each species are given.

Abstract: Four lichen species, Parmelia sulcata Taylor, Hypogymnia physodes (L.) Nyl., Cetraria islandica (L.)Ach., and Bryoria fuscescens (Gyelnik) Brodo andHawksworth were exposed during autumn and winter at differentsites of the Erzgebirge (Ore Mountains), the Fichtelgebirge andcontrol sites. All lichens tested became visibly damaged withtime. Thallus bleaching started from the edges and went on tothe centre of the thallus. Sites of facilitated gas exchangelike the soralia of P. sulcata and the pseudocyphelles ofC. islandica became preferentially bleached. The sulfateconcentration increased with exposure time reaching 200% ofunpolluted controls. In contrast to coniferous trees (e.g. Picea abies), further exposure lead to a reduction in the S-concentration in the lichens, as sulfate and otherintracellular metabolites were leached from the thalli due tomembrane damage. The changes in the K-concentration proved tobe an excellent measure for membrane leakiness; it wascorrelated with time of exposure and with SO2 concentrations at the different sites. Photosynthetic capacityand respiration were also strongly affected. Depending on theSO2-dose, the Bryoria species were unable tophotosynthesize as early as 4–8 weeks after exposure, whereasCetraria and Hypogymnia showed clear reduction intheir ability to photoreduce CO2 within 8–10 weeks ofexposure in the field. Parmelia sulcata was found to bethe most tolerant species. After 3–4 months, photosynthesis wasreduced by only 30%. The bioindicative value of theseobservations is discussed.

Abstract: Biological soil crusts are important microphytic communities and significantly influence both structure and processes within the ecosystem. They are built up from cyanobacteria, green algae, fungi, mosses and lichens. Various crust types could be found, depending on dune slope aspect and dewfall availability. In the sand dunes of the northern Negev they cover large areas and stabilize the sand surface against wind and water erosion. Free-living and symbiontic cyanobacteria are capable of nitrogen fixation and are important nitrogen sources in the desert sand dunes. As biological crusts enhance the surface stability and soil fertilization, they are to be considered a key factor in the protection of arid and semiarid ecosystems and, thus, in combating desertification in terms of sand dune remobilization.

Abstract: There are ca. 70 000 "woodland key habitats" (WKHs) in Sweden that according to definition should contain red-listed species, but their species content is seldom known. Indicator species are used a...

Abstract: We investigated the potential for nonvascular epiphytic species (primarily lichens) to affect the quality of different host tree species for the vascular epiphyte Tillandsia usneoides in the southeastern USA. Different host tree species had substantially different abundances of Tillandsia, and these abundances were correlated with the composition of nonvascular epiphyte communities. In greenhouse experiments Tillandsia grew significantly faster on the branches of Quercus virginiana (a species with very high natural abundances of Tillandsia) when the dominant lichen on Q. virginiana was left intact than when the lichen was removed from the branches. In laboratory experiments, extracts from Cryptothecia rubrocincta, a lichen that was 10 times more common on poor host species for Tillandsia than on good host species, reduced Tillandsia seedling survival and growth in comparison to extracts from other species and rainwater. In field experiments, lichens increased the proportion of Tillandsia seeds and vegetative strands that adhered to the trunk of Ilex opaca (a poor Tillandsia host), but lichens did not affect propagule adherence to Q. virginiana. Our results are by no means exhaustive of the possibilities, but they suggest that the structure and diversity of vascular and nonvascular epiphytic communities that grow in different tree species may not be simply the product of host tree characteristics, but may also be influenced by interactions among the epiphytes themselves.

Abstract: Recolonisation of trampled lichen pastures in the High Arctic is dependent on the regrowth from small fragments of lichen thalli. Intact lichens have been shown to grow most rapidly during periods of sustained moisture caused by rainfall or cloudy days. Climate change models for Arctic areas predict wetter summers, milder winters and greater stochastic variability. Therefore we hypothesised that the growth of both damaged and intact Svalbard reindeer forage lichens would be increased under the future climatic scenarios. The effects of rainfall frequency, increased precipitation, and simulated cloud cover on relative growth rate (RGR) of Cetraria delisei, C. islandica and C. nivalis, from NW Svalbard were examined under controlled conditions. Low light did not depress RGR, suggesting that shading provided by increased cloud cover would not affect the lichen growth. The ability to gain mass and the RGR was lower in cut thalli than intact thalli under most watering regimes. Frequency of watering was the most important factor influencing growth, but this also interacted synergistically with quantity. Damaged thalli watered frequently grew significantly more than intact thalli watered less frequently. These results suggest that an increase in summer precipitation as predicted by climate modelling would increase the growth rate of fragmented thalli and may help to ameliorate the damage done to the lichen thalli by reindeer trampling and grazing.

Abstract: Abstract: Epiphytic lichens (and some non-lichenized fungi) on 34 coppices (204 stems) of Corylus avellana were investigated in a 140 ha study area in south-western Norway. A total of 65 species were recorded on a total bark area of 63 m 2 . Corylus in broad-leaved deciduous forest supported more species of macrolichens, and fewer species of microlichens, than Corylus in pine forest. The macrolichen flora of the deciduous forest differed from that of the pine forest by having a rich flora of species belonging to the Lobarion alliance. Old Corylus coppices with tall stems (>8 m), large girth (>8 cm diameter at breast height) and a noticeable cover of macrolichens (>10% of bark area) supported the highest number of rare species, and overall, species of macrolichens. More than 50% cover of microlichens indicated richness and rarity of microlichens on Corylus .