Factors at multiple scales influence the composition of terricolous lichen communities in temperate semi-arid sandy grasslands

Inland dune ecosystems are rich in terricolous lichen species. However, these communities are sensitive to human activities, both locally and globally. Since terricolous lichens have a dominant role in semi-arid sandy grasslands, it is important to explore the composition of their communities and the environmental factors affecting them. We studied the structure of the terricolous lichen assemblages of calcareous grassland in an inland duneland ecosystem by comparing the lichen communities of arid and humid dune sides on two sites with different disturbance histories. Microcoenological data were collected according to the Braun-Blanquet method. Environmental variables include the cover of bare soil, moss, litter, herb cover and height of herbs. We investigated the relationship of these variables and the presence and absence data of terricolous lichen species to sites and dune side. We found that the site had a significant effect on species richness that might reflect the different types and severity of previous disturbance events at the studied sites. On a smaller, ‘dune’ scale, in general lower herb cover and height and a higher moss cover were characteristic of arid dune sides. Most of the frequent species were negatively affected by higher moss cover. Some lichen species were more abundant (e.g. Cladonia furcata) or found only (e.g. Xanthoparmelia subdiffluens, Gyalolechia fulgens) on arid dune sides, while others preferred (e.g. C. pyxidata) or occurred only on (e.g. Peltigera species, C. rei) humid sides. It was observed that the impact of the dune side on several variables differed between sites. The diverse microhabitat types, microclimate and landscape structure, results in species-rich and valuable terricolous lichen communities forming in inland dune ecosystems.

Morphological and Chemical Traits of Cladonia Respond to Multiple Environmental Factors in Acidic Dry Grasslands

Terricolous lichen communities in lowlands occur especially in open dry habitats. Such communities are often dominated by species of the genus Cladonia, which are very variable in morphology, reproduction strategies, and secondary metabolites. In this work, we investigated traits-environment relationships considering vegetation dynamics, substrate pH, disturbance, and climate. A total of 122 plots were surveyed in 41 acidic dry grasslands in the western Po Plain (Northern Italy). Relationships between Cladonia traits and environmental variables were investigated by means of a model-based Fourth Corner Analysis. Thallus morphology and metabolites responded to vegetation dynamics, substrate pH, disturbance, and climate, whereas reproduction strategies responded only to vegetation dynamics. Traits’ correlations with vegetation dynamics elucidate their colonization patterns in open dry habitats or suggest biotic interactions with bryophytes and vascular plants. In addition, correlations between metabolites and environmental factors support interpretations of their ecological roles. Our results also stress the importance of studying traits’ relationships with climatic factors as an alert towards lichen reactions to climate change.

Rhagadodidymellopsis endocarpi gen. et sp. nov. and Arthopyrenia symbiotica (Dothideomyceta), two lichenicolous fungi growing on Endocarpon species

The lichenicolous fungus Rhagadodidymellopsis endocarpi (Dothideomyceta) growing on the thallus of the terricolous lichen Endocarpon pusillum is described from Spain and Australia as new to science. The new genus and species is compared with other taxa from the genera Didymellopsis and Zwackhiomyces (Xanthopyreniaceae, Collemopsidiales, Dothideomyceta), in particular with D. perigena, a species also having hyaline didymospores and also growing on Endocarpon. Rhagadodidymellopsis endocarpi is characterized by its almost completely superficial stromatic ascomata with a coarse and irregular surface, and an ascomatal wall of very irregular thickness, and ascospores smaller than those of D. perigena. We also compare the new species with other Endocarpon parasites, including Arthopyrenia symbiotica. This is a misunderstood species, originally described as Verrucaria symbiotica, which we also discuss in detail in this study.

Diversity and distribution of lichens in recently deglaciated areas of southeastern Spitsbergen

The diversity and distribution of lichen species were investigated in recently deglaciated areas of the borderland between Sørkapp Land and Torell Land (southeastern Spitsbergen, Svalbard). A total of 15 sites representing various habitat types specific to the area were evaluated. Sampling sites were characterized by a very diverse composition of lichens and species richness ranging from as few as two species to as many as 53. None of the species was ubiquitous among the investigated sampling sites; conversely, most were recorded only once or twice indicating a high heterogeneity in species distribution. Eighty species are reported for the first time from southeastern Spitsbergen. The terricolous lichen <em>Verrucaria xyloxena</em> is reported for the first time from the Svalbard archipelago. The influence of the selected abiotic and biotic environmental factors on the occurrences and distributions of lichen species is discussed in this paper.

The Role of Substrate Type, Moisture and Temperature on the Vertical Growth of Terricolous Lichens

Lichens are traditionally divided into short &ldquo;crustose&rdquo;, intermediate &ldquo;foliose&rdquo; and tall &ldquo;fruticose&rdquo; types, a practice that hides a growth continuum. Substrate, temperature and water are thought to affect vertical growth, but such factors are difficult to measure, because, for example, the water actually available to lichens does not match rainfall patterns or even ground water levels. To reliably assess the effect of those factors, I recorded temperature, moisture, and substrate in and under individual terricolous lichen colonies in 60 fixed quadrats on April, August, October, and December of 2015 (Cerro de la Muerte, Costa Rica, 9&deg;33&prime;N; 83&deg;45&prime;W). The measurements were taken inside the colonies themselves (rather than on the general environment), covering an annual cycle of the relatively simple p&aacute;ramo habitat, where animals and vegetation have less impact than in lower ecosystems. The hypotheses were that lichens would grow taller on softer, warmer, and moister ground; on the Caribbean versant; and on the rainy season. Results matched the hypotheses, with one exception: lichens on soft ground were not taller than those on rock. Caribbean colonies were, on the average, 7 cm taller than those on the drier Pacific versant. Physiologically available water seems to be the main determinant of lichen vertical growth: more water means taller lichens and greater protection from climatic change for both the lichens and their microcommunities.

The role of substrate type, moisture and temperature on the vertical growth of terricolous lichens

Lichens are traditionally divided into short “crustose”, intermediate “foliose” and tall “fruticose” types, a practice that hides a growth continuum. Substrate, temperature and water are thought to affect vertical growth, but such factors are difficult to measure, because, for example, the water actually available to lichens does not match rainfall patterns or even ground water levels. To reliably assess the effect of those factors, I recorded temperature, moisture, and substrate in and under individual terricolous lichen colonies in 60 fixed quadrats on April, August, October, and December of 2015 (Cerro de la Muerte, Costa Rica, 9°33′N; 83°45′W). The measurements were taken inside the colonies themselves (rather than on the general environment), covering an annual cycle of the relatively simple páramo habitat, where animals and vegetation have less impact than in lower ecosystems. The hypotheses were that lichens would grow taller on softer, warmer, and moister ground; on the Caribbean versant; and on the rainy season. Results matched the hypotheses, with one exception: lichens on soft ground were not taller than those on rock. Caribbean colonies were, on the average, 7 cm taller than those on the drier Pacific versant. Physiologically available water seems to be the main determinant of lichen vertical growth: more water means taller lichens and greater protection from climatic change for both the lichens and their microcommunities.

The genus Endocena (Icmadophilaceae): DNA evidence suggests the same fungus forms different morphologies

Numerous recent studies of lichenized fungi have uncovered hidden genetic diversity within a single phenotypic entity (so-called ‘cryptic species’). Here we report the opposite situation with vastly different morphologies apparently deriving from the same genotype. Endocena is a monotypic genus known only from southern South America. The single reported species, the terricolous E. informis, is morphologically variable; the type and other collections from the west coast of Chile being subfruticose, whereas specimens from further south and east are almost crustose in form. A sorediate terricolous lichen that is frequent on the Falkland Islands was confirmed by phylogenetic analysis of ITS rDNA and mtSSU rDNA sequences as being congeneric with E. informis and, surprisingly, both taxa were recovered as congeneric with the recently described genus and species Chirleja buckii, which is morphologically distinct from both E. informis and the sorediate taxon. Consequently, the genus Chirleja is included in the synonymy of Endocena and the new combination Endocena buckii is proposed. Because E. informis and the sorediate specimens have a similar thallus structure that differs radically from that of E. buckii, the name E. informis var. falklandica is proposed for the sorediate taxon. Poorly developed, incipient apothecia are also described from both varieties of E. informis, the first time that these have been reported for Endocena. We also report two lichenicolous fungi from E. informis var. informis, which are the first reports of lichenicolous fungi occurring on this genus.