Abstract: Microbiotic crusts are biological soil crusts composed of lichens, cyanobacteria, algae, mosses, and fungi. The biodiversity of these crusts is poorly understood; several cosmopolitan species dominate in most areas, but many species are confined to one or a few sites. Nitrogen fixation by organisms within the crust can be the dominant source of nitrogen input into many ecosystems, although rates of nitrogen input are limited by water availability, temperature, and nitrogen loss from the crust. Photosynthetic rates of the microbiotic crust can be 50% of those observed for higher plants, but the contribution of crusts to carbon cycling is not known. The microbiotic crust binds soil particles together, and this significantly increases soil surface stability and resistance to erosion. Greenhouse studies have found that crusts can enhance seed germination, seedling survivorship, and plant nutrient status, but further experiments are needed under field conditions. Crusts are extremely susceptible to surface dis...

Abstract: In the Netherlands a monitoring programme is in operation to map the effects of ammonia pollution with epiphytic lichens. The method is presented here and the results are statistically correlated with abiotic data. The abundance of nitrophytes onQuercus roburappears to be a useful parameter. Detailed spatial patterns of ammonia pollution can be obtained with lichens. To avoid interference, it is important to consider other influences, for example dust, climate, exposure, age of the trees and other pollutants.

Abstract: An important issue in conservation biology is the extent to which one group of organisms can function as a surrogate for less well-known groups. We explored the extent to which vascular plant species di- versity (both a -diversity, or species richness, and b -diversity, or turnover) and the subgroups of understory, overstory, and ferns can act as surrogates for bryophyte and lichen species diversity. We surveyed 35 sites in a range of forest types in the coastal lowlands of eastern Australia. Fern species richness was strongly positively correlated with bryophyte species richness but negatively correlated with lichen species richness. Fern, bryo- phyte, and lichen species richness all varied significantly with time since fire, vascular plant cover, and topo- graphic position gradients. Of the other vascular plant groups, the only significant correlation was between overstory and bryophyte species richness. We quantified species turnover using modifications of Whittaker's original measure as well as multivariate techniques. The rate of lichen species turnover was the lowest of all six groups investigated. The other five groups had similar rates of species turnover, although the results were different depending on the emphasis of the measure used. There were significant correlations between the pat- terns of species turnover of bryophytes and lichens and those of all four vascular plant groups, but none of the correlations was particularly strong. The understory and all vascular plants were the best predictors of the species turnover pattern of bryophytes and lichens, and correlations appeared strongest in wet sclerophyll sites. With respect to management practices, time since the last fire appears to be an important determinant of bryophyte, lichen, and vascular plant diversity, and logging appears to differentially affect the diversity of the different plant categories. A mosaic of logging and fire intervals and intensities appears to be important for maintaining regional diversity.

Abstract: The diversity and abundance of terrestrial, lithophytic cyanobacteria in tropical biomes and the variety of rock habitats which they occupy are discussed. The following results are presented in detail. Exposed rock surfaces on different continents and under different climatic conditions are occupied by a cosmopolitan, well-adapted, low-diversity microbial community dominated by cyanobacteria and cyanobacterial lichens. For inselbergs (isolated rock outcrops) in dry savanna, the ratio of rock covered by lichens to that covered by free cyanobacteria is approximately 5:3. In humid savannas this ratio is approximately 1:26, and in rainforests there are hardly any lichens on rocks. The primary production of epilithic communities, expressed as CO2 fixed calculated from chlorophyll a, can reach an annual 27 g m−2. When calculated for a hypothetical inselberg, production values for very dry thorn bush savanna, dry savanna and humid savanna are 1:3.2:4.2 on the basis of the entire inselberg, and 1:3.2:1.4 when cal...

Abstract: Total concentrations of Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Pb, Sr, Ti, V and Zn in the epiphytic lichen Parmelia sulcata and superficial soils from 60 remote sampling sites in Tuscany (central Italy) were determined to evaluate the contribution of soil to the elemental composition of the lichen. The results showed that in the Mediterranean environment, the trace element content of unwashed lichen samples is greatly affected by soil contamination. However, despite the strong correlations between the concentrations of lithogene elements such as Al, Fe and Ti in P. sulcata, lichen levels of these elements were not at all linearly correlated with their concentrations in the soil, suggesting that dust contamination is highly variable and probably dependent on local site characteristics. All methods evaluated to minimize soil contamination indicated Cu, Pb and Zn as elements of atmospheric origin. However, while levels of Pb were similar to those reported for background areas, moderate pollution by Cu and Zn, probably from fertilizers used in agriculture, was revealed. For elements such as Cd and Mo, identified as atmophile, some uncertainty exists due to the fact that they are essential for lichen metabolism and accumulate intracellularly in lichens; they may therefore occur in soluble form in the lichen thallus.

Abstract: Dispersal patterns from seven terricolous lichen species, with a high capacity for asexual reproduction by fragmentation (Cetraria muricata, Cladonia species), were studied in differing vegetation types in north-eastern Germany. Marked lichen thalli were fragmented by trampling. After 15 days the spread of thallus fragments was monitored. Whereas most of the fragments that were dispersed by wind remained within a 20-cm radius from the source, the maximal dispersal distance was 57 cm in a dry sand grassland and 68 cm in an open pioneer pine forest. Dispersal was negligible in a closed old-growth pine forest. Several fragmented lichen cushions were disturbed and removed by animals, and led to a maximal dispersal distance of 9·70 m. These results suggest that: (a) thallus fragments provide good short-distance dispersal in open vegetation, but are inefficient for long-distance dispersal, and (b) wind and animals are important factors for the dispersal of thallus fragments. For restoration management of man-made substrata, artificial introduction of lichen thalli is proposed.

Abstract: The photobiont inventory of a stand of the Acarosporetum sinopicae, a lichen community comprising saxicolous, chalcophilous lichens, has been analysed. Investigated lichen species were Acarospora rugulosa, A. sinopica, Bellemerea diamartha, Lecanora polytropa, L. subaurea, Lecidea silacea, L. lapicida, Rhizocarpon geographicum, and Umbilicaria cylindrica. For all these lichen species this is the first record of the photobionts, except for L. lapicida. The photobionts were cultured axenically and investigated using light microscopical and molecular methods (ITS-sequence analyses). Every lichen species contained only one photobiont species. All photobionts belong toTrebouxia jamesii , but two different subspecies were found with the morphological differences corresponding to molecular differences. The new subspecies T. jamesii subsp. angustilobata is described, differing from the typical T. jamesii by a crenulate chloroplast but identical to the latter taxon in respect to the pyrenoid structure in the light microscope. These results are discussed with respect to the photobiont inventory of the Physcietum adscendentis, analysed in an earlier study.

Abstract: All Swedish forest land is at present being surveyed with the aim of mapping woodland key habitats which have an estimated number of ca. 70 000. An untested requirement of these habitats is that they should contain red-listed species. In order to investigate if they fulfill their aim, an inventory of nationally red-listed bryophytes and lichens was performed in ca. 120 randomly selected woodland key habitats distributed throughout the country. The species were recorded in line transects, covering the whole surface of the habitats. The mean number of red-listed species per habitat was 0.7 for bryophytes and 1.4 for lichens with 11 species at the richest site and 71% of the sites having at least one species. Nemoral forests and coniferous forests were the most species-rich habitat types. The habitats of northern Sweden were more species rich than the southern ones. There were weak correlations between presence of bryophytes and lichens. The study shows that a majority of the woodland key habitats contain red-listed bryophyte and lichen species. Further studies are needed in order to record more organism groups and to compare the woodland key habitats with the surrounding matrix forests.

Abstract: An annotated checklist of the lichens of Hong Kong, based on all available literature reports and specimens, including those recently collected by the authors, is presented. In total, 261 species are reported, of which 176 are new records for Hong Kong, 132 of which are new for China, 43 are new for East Asia, and 27 are new for Asia. The lichen vegetation is mainly tropical, as is shown by the distribution patterns of the identified species: 53 species are cosmopolitan, 40 northern temperate, 122 pantropical, 17 paleotropical and 29 endemic to tropical East Asia. With regard to substrata, 129 species are corticolous, 148 saxicolous, 17 foliicolous and 19 terricolous. Four species are newly described: Anisomeridium conorostratum Aptroot, A. hydei Aptroot, Caloplaca pulicarioides Aptroot and Placidiopsis poronioides Aptroot. The flora is rather poor in species; for example, no Caliciales have been found. In the past, the numbers of species of several groups such as the Graphidaceae, Heterodermia and Xanthoparmelia have been overestimated, whereas few pyrenocarps have been reported. The flora of wet granitic outcrops is surprisingly well developed in Hong Kong. Although not a single Peltula species was reported before, six species were identified, including one that was previously only known from Africa. In addition, several other cyanophilic genera are present, such as Euopsis , Psorotichia , Pyrenopsis and, most unexpectedly, Vestergrenopsis , each with one species. A comparison between old and recent records shows that many Lobarion species are now extinct. The drastic decline of species of the Lobarion vegetation indicates that air pollution and other habitat disturbances, mainly deforestation, to which these species are very sensitive, are seriously threatening the lichen biodiversity of Hong Kong.

Abstract: Lichens are symbiotic associations between fungi and algae and/or cyanobacteria. They produce common intracellular products including proteins, amino acids, polyols, carotenoids, polysaccharides and vitamins. The secondary metabolites found in lichens are phenolics which accumulate either on the cortex or on the cell walls of medullary hyphae and they are mainly acetyl-polimalonyl pathway derivatives. Polysaccharides, proteins and secondary metabolites produced by lichens have attracted the attention of investigators due their biological activities. This revision coments about the biosynthetic origin and structures of the principal classes of compounds produced by these organisms.

Abstract: The results from several floristic and bioindication projects in Central Switzerland (1986–1998), focusing on the effects of agriculture, particularly from nitrogen and agrochemical emissions, are summarized. The abundance of nutrient-tolerant lichen species and the decreased occurrence of nitrophytic lichens are both correlated with agricultural land use and high atmospheric deposition. The impact could be demonstrated not only by the distribution patterns of nutrient-tolerant species, but also by the high N content of lichens such as Physcia caesia . Positive growth response of Cetraria islandica to application of mineral nutrients and increased CO 2 in open-top chambers at high altitudes was also observed. The methods and a survey of the results from studies conducted within the framework of the lichen research programme of the Natural History Museum of Lucernce are presented here. A discussion of the issues shows the need for further studies concenring the influence of introduced nutrients on the biodiverisyt of lichens.

Abstract: A survey of epiphytic species on annual increments of Quercus petraea twigs in west Wales woodland has shown that distribution of lichen species and rates of succession are affected by a range of environmental conditions. Lichen communities were recorded for 1-15 years on randomly sampled twigs along marked woodland boundaries affected by a range of climatic and management conditions. Results show that there is a correlation between environmental conditions and lichen communities of twigs, and that indicator species can be used to detect trends towards acidification or eutrophication.

Abstract: The aim of this paper is to verify whether lichens have the capacity to accumulate atmospheric contaminators linked to volcanic activity. About 100 lichens were collected in 1994 and 1995 from two active volcanic areas in Italy: Mount Etna and Vulcano Island. Twenty-seven elements were analyzed for each individual lichen using Instrumental Neutronic Activation Analysis and Inductively Coupled Plasma-Mass Spectrometry. Lichen composition reflects the contribution of the volcanic particulate material, and the two areas investigated can be distinguished on the basis of the concentration of some lithophile elements. Moreover, the distribution in lichens of the elements (As, Sb, Br, Pb) – derived from gas emissions (plume, fumaroles) – also shows different geochemical trends on Mt. Etna and Vulcano.

Abstract: The nature and significance of morphologically indistinguishable chemical races have been active areas of lichenological research for decades. This study uses a phylogenetic analysis of rDNA sequences to investigate whether the morphologically indistinguishable chemotypes of Ramalina americana are distinct species. Cladistic analysis of ITS sequences from 19 R. americana individuals (representing eight of the nine described chemotypes) and four outgroup Ramalina species reveals that R. americana comprises at least two cryptic, phylogenetic species. One, R. americana, is largely acid-deficient and occurs in the northern half of the range of the complex (and at high elevations in the Southern Appalachian Mountains); the other, R. culbersoniorum sp. nov., encompasses most of the chemical diversity and occurs in the southern half of the range. There is no meaningful resolution within either species. Among the outgroup Ramalina species, R. intermedia appears to be sister to the northern species, while R. fastigiata, the presumed sister group to the complex, forms an unresolved trichotomy with both the northern and southern species. Ramalina sinensis, often assumed to be closely related to the complex, is only distantly related. The results of this study agree with previous studies of other lichens in that each chemotype does not represent a separate species, nor are they all conspecific. Rather, the complex can be divided into two species, each consisting of multiple chemical races. Secondary-product chemistry has been an important tool in lichen systematics for over a century (Elix 1996; Hawksworth 1976). Since Nylander's (1866) first applications of thallus spot-tests to lichens, it has been recognized that many morphologically similar species of lichens can often be separated on the basis of their secondary products. Many morphs, however, comprise multiple, visually indistinguishable chemical races (chemotypes). In some organisms, such as pines (Yazdani et al. 1985), it is often easy and accurate to recognize such chemical variants as within-species polymorphisms because the secondary products vary only in their proportions to one another, and this variation is gradual across a given morphological species' geographical range. In lichens, however, chemical variation is often discrete: different chemotypes usually have qualitatively different compounds and largely non-overlapping geographic ranges. In cases where certain lichen chemotypes share some or all of the same compounds (chemosyndromic variation-Culberson & Culberson 1976; Feige & Lumbsch 1995), the relative proportions of these compounds usually vary in a discrete and predictable fashion. In addition, a strong genetic component to lichen chemistry has been demonstrated (C. E Culberson et al. 1983, 1988), and over the years, workers have correlated chemotype with ecology, geography and/or micromorphology (W. L. Culberson 1986) in various lichens. Given this evidence, the elevation of many lichen chemotypes to species status is justifiable; however, it is often a point of contention. Arguments for (W. L. Culberson 1969, 1986; Poelt 1972) and against (Almborn 1965; Lamb 1951; Rogers 1989) recognizing lichen chemotypes as species have been presented and the debate is ongoing (Lumbsch 1998a). Recently, the investigation of chemosyndromic variation within previously poorly known taxa has been advocated (Zeybek et al. 1993). The careful correlation of chemosyndromic variation with other types of character variation (a posteriori evaluation of chemical characters; Lumbsch 1998a, b) has shown that the presence of a biogenetic series of chemosyndromes can be more important for species recognition than the presence or absence of individual compounds. The present study addresses the phylogenetic utility of chemistry in the Ramalina americana chemotype complex. Ramalina americana is a group of small, tufted lichens that reproduce exclusively by spores. These lichens grow on hardwood trees throughout the eastern United States and Canada (Fig. 1). The species was separated from the European R. fastigiata by Hale (1978), who described a northern, acid-deficient race (R. americana sensu stricto) and a southeastern population consisting of multiple chemotypes. Dey (1978) de0007-2745/99/602-618$1.85/0 This content downloaded from 207.46.13.131 on Sun, 16 Oct 2016 05:14:28 UTC All use subject to http://about.jstor.org/terms 1999] LAGRECA: RAMALINA AMERICANA 603

Abstract: Lucking, R.: Foliicolous lichens and their lichenicolous fungi from Ecuador, with a comparison of lowland and montane rain forest. – Willdenowia 29: 299-335. 1999. – ISSN 0511-9618. A rich collection of foliicolous lichens from Ecuador gathered at the Biological Stations Jatun Satcha and Guajalito, two representative localities in the lowland and the montane rain forest, yielded a total of 297 species, including 15 facultatively foliicolous taxa and 11 lichenicolous fungi. Twelve species are described as new: Aspidothelium mirabile, A. ornatum, A. scutellicarpum [ Aspidopyrenium insigne var. dispersum], Asterothyrium gigantosporum, A. longisporum, Dimerella vezdana, Gyalideopsis albopruinosa, Porina napensis, P. pichinchensis, Psorotheciopsis guajalitensis, Tapellaria marcellae and Tricharia verrucifera. Furthermore, the new combination Porina repanda [≡ Verrucaria repanda] is made. Species diversity is the second highest known in the world, after Costa Rica with approximately 380 species. Species composition is remarkably similar to that of Costa Rica, which exhibits a similar landscape physiognomy. However, the lowland rain forest of Ecuador still remains undercollected. The lowland and the montane rain forest sites differ markedly in their foliicolous lichen flora. Arthonia, Aspidothelium, Echinoplaca, Mazosia and Gyalideopsis are the most discriminative genera between the two forest types with respect to diversity and species composition.

Abstract: The photobiont inventory of a stand of the Acarosporetum sinopicae, lichen community comprising saxicolous, chalcophilous lichens, has been analysed. Investigated lichen species were Acarospora rugulosa, A. sinopica, Bellemerea diamartha, Lecanora polytropa, L. subaurea, Lecidea silacea, L. lapicida, Rhizocarpon geographicum, and Umbilicaria cylindrical. For all these lichen species this is the record of the photobionts, except for L. lapicida. The photobionts were cultured axenically and investigated using light microscopical and molecular methods (ITS-sequence analyses). Every lichen species contained only one photobiont species. All photobionts belong to Trebouxia jamesii, but two different subspecies were found with the morphological differences corresponding to molecular differences. The new subspecies T. jamesii subsp. angustilobata is described, differing from the typical T. jamesii by a crenulate chloroplast but identical to the latter taxon in respect to the pyrenoid structure in the light microscope. These results are discussed with respect to the photobiont inventory of the Physcietum adscendentis, analysed in an earlier study.

Abstract: The epiphytic lichen vegetation of 20 sites around Thessaloniki (Macedonia, northern Greece) surveyed in 1987 was sampled again in 1997 to monitor any changes in lichen communities and consequently in air quality. A general impoverishment in lichen communities was recorded in the 10-year period, presumably chiefly due to changes in the air pollution status. A small increase in lichen species diversity was recorded in some stations, probably as a result of the buffering capacity of airborne dust.

Abstract: A total of 217 species of typically foliicolous lichens were found at the “Botarrama” trail, a premontane rain forest in the Braulio Carrillo National Park, Costa Rica. The species composition confirmed the classification of this study sice as transitional between lowland wet and montane rain forest. In terms of species tichness, the foliicolous lichen flora was dominated by the families Gomphillaceae (Calenia, Echinoplaca, Gyalideopsis, and Tricharia), Trichotheliaceae (Porina and Tricbothelium), and Pilocarpaceae (Byssoloma and Fellhanera). The most frequent species were Porina mirabilis (including its supposed anamorph Phyllophiale alba), Gyalectidium filicinum, Porina rufula, and Strigula platypoda. A large proportion of the species was rare. Frequency distributions based on area cover corresponded well to general community models by closely fitting a log-normal approximation. Half of the species had narrow ecological amplitudes while more than 70 percent exhibited a wide geographical distribution, thus making che study site representative of a Neotropical rain forest. The use of foliicolous lichens as indicators of altitudinal zonation is discussed.

Abstract: Measurements were made of density, size and shape of colonies of the soil lichen Psora crenata at sites with varying disturbance histories at Maralinga in arid South Australia. Lichens were measured along transects at 10 sites with recovery intervals ranging from 3 to 42 years, and on four undisturbed control sites. As the time since disturbance increased, the number of lichen colonies increased markedly, colony size declined, but colony shape remained unchanged. We tentatively suggest that at least 60 years is required for disturbed sites to approach the condition of undisturbed sites. These results reinforce the notion that lichen recovery is very slow, and suggest that colony density of Psora could be a useful indicator of recovery after disturbance in rangelands where crusts are a common component of the soil surface. Keywords: Psora crenata, rangelands, soil crusts, cryptogams, rangeland health