Influence of freezing processes on the vegetation of Sakhalin swamps

Herewith the current characteristics of the bog vegetation on the Chaivo spit in the north of Sakhalin are outlined. The many-year surveys have discovered icy permafrost at a depth of 45-70 cm which leads to the formation of annual and perennial migratory pingos. Herewith a brief description of the changes of the pingo vegetation is provided, it has been discovered that the process of lichen growth on the pingos is of selective nature. It has been noticed that some pingos on the bogs of the Chaivo spit have increased in size, which obviously demonstrates the process of replacement, firstly, of mosses by lichens, which in their turn are replaced by herbs and mall shrubs, i.e. pingos on different phases of development can be found. During the period of the surveys, it has been identified that the share of perennial pingos covered with lichens has increased.

Onset of Aegean-style extensional deformation in the contractional southern Dinarides documented by incipient normal fault scarps in Montenegro

We describe two previously unreported, 5–7 km long normal fault scarps (NFS) occurring atop fault-related anticlines in the coastal ranges of the Dinarides fold-and-thrust belt in southern Montenegro, a region under predominant contraction. Both NFS show well-exposed, 6–9 m high, striated and locally polished fault surfaces in limestones, documenting active faulting during the Holocene. Sharply delimited ribbons on free rock faces show different color, varying karstification and lichen growth and suggest stepwise footwall exhumation, typical of repeated normal faulting earthquake events. Displacements, surface rupture lengths and geometries of the outcropping fault planes imply paleoearthquakes with Mw ≈ 6 ± 0.5 and slip rates of c. 0.3–0.5 mm/yr since the Last Glacial Maximum. Slip rates based on cosmogenic 36Cl data from the scarps are significantly higher: modeling suggests 1.5 ± 0.1 mm/yr and 6–15 cm slip every c. 35–100 yrs, commencing c. 6 kyr ago. The total throw on both NFS – although poorly constrained – is estimated to max. 200 m, and offsets the basal thrust of a regionally important tectonic unit. Both NFS are incipient extensional structures that postdate growth of the fault-related anticlines on top of which they occur. Interestingly, the position of the extensional features agrees with recent geodetic data, suggesting that our study area is located exactly at the transition from NE-SW-directed shortening in the northwest to NE-SW-directed extension to the southeast. While the contraction reflects ongoing Adria-Europe convergence taken up along the frontal portions of the Dinarides, the incipient extensional structures might be induced by rollback of the Hellenic slab in the SE, whose effects on the upper plate appear to be migrating along-strike the Hellenides towards the northwest. The newly found NFS provide evidence for a kinematic change of a thrust belt segment over time. Alternatively, the NFS might be regarded as second-order features accommodating changes in dip of the underlying first-order thrust faults to which they are tied genetically.

Remarkable cases of parallel evolution of the placodioid thallus growth form in the Lecanographaceae (Arthoniales) with the description of a new species of Alyxoria from Mexico

The new species Alyxoria sierramadrensis is described from Mexico where it inhabits limestone rocks. The lichen developing from this fungus is characterized by a placodioid to subfoliose thallus with a white pruinose surface; rounded to shortly elongated ascomata with a black epruinose margin and a widely exposed, white pruinose hymenial disc; hyaline, 3-septate ascospores, 17–25 × 7–9 μm; the presence of anthraquinones rendering the medulla orange. Phylogenetic analyses of nuLSU, mtSSU and RPB2 sequences place this species in the genus Alyxoria (Lecanographaceae). This generic affiliation is surprising because all known Alyxoria species have a crustose thallus. Lecanographaceae mainly includes species without a thallus (lichenicolous taxa) or with a thin crustose thallus, the only exception being Simonyella variegata with a fruticose thallus. The new species belongs to the Alyxoria ochrocheila subgroup, which includes lichens also frequently known to have anthraquinones, white pruinose hymenial discs and 3-septate ascospores. Phylogenetic analyses further determined the systematic position of the monotypic genus Phoebus. This genus, considered as an Arthoniales of uncertain family affiliation, is shown to belong to the Lecanographaceae. With its placodioid thallus, it is another example of a lichenized fungus with a deviating morphology in thallus structure for the family, increasing the number of remarkable cases of parallel evolution of lichen growth forms within the Arthoniales. Phoebus hydrophobius is newly recorded for Mexico.

A review of reindeer lichen (Cladonia subgenus Cladina) linear growth rates

Cladonia subgenus Cladina (the reindeer lichens) can be a dominant part of terrestrial ecosystems worldwide. They are particularly abundant in arctic-alpine and boreal regions, where they are a primary food source for woodland caribou/reindeer in winter months. Determining the growth rates of reindeer lichen is important for understanding and managing lichen regeneration following disturbances such as timber harvesting, mining, grazing, and wildfire. Regeneration and rehabilitation rates can be calculated with greater accuracy when growth rates are well understood. We provide a summary of 17 studies from 6 countries that determined the linear growth rates of three reindeer lichen groups, Cladonia arbuscula/mitis (mean = 4.7 mm/yr.), C. rangiferina/ C. stygia (mean = 5.1 mm/yr.), and C. stellaris (mean = 4.8 mm/yr.). We use linear growth rates as a proxy for over-all growth and biomass. Variables found to influence lichen growth rates are also discussed, which include light, moisture, temperature, air pollution, acid rain, precipitation, snow accumulation, substrate, age of individuals, and type of disturbance. These results can assist land managers in developing more accurate strategies for restoring lichens in disturbed areas.

Estimating the age and mechanism of boulder transport related with extreme waves using lichenometry

Tsunamis and storms cause considerable coastal flooding, numerous fatalities, destruction of structures, and erosion. The characterization of energy and frequency associated with each wave contribute to the risk assessment in coastal regions. Coastal boulder deposits represent a physical proof of extreme inundation and allow us to study the effects of marine floods further back in time than instrumental and historical records. Age estimation of these deposits is challenging due to lack of materials (such as sand, shells, corals, or organic matter) that retain information about the passage of time. Lichenometry, a simple age estimation method, which is cost-effective, quick to apply, and non-destructive, is here proposed as a solution. A lichen growth model for a calcium-tolerant lichen species was developed and used to estimate the age of a boulder deposit related to extreme marine inundation(s) in Portugal. Estimated ages indicate several very recent events (<700 years) for most of the boulders’ stabilization and agree with results obtained with optically stimulated luminescence of marine sands found beneath boulders. Frequent and recent boulder transport implies a storm-origin for this deposit. These conclusions contrast with other works describing identical deposits that are attributed to paleotsunamis. This study presents a methodology using lichenometry as a successful alternative for age estimation in rocky coastal settings. These results offer an alternative explanation for coastal boulder deposits found on the west coast of Portugal.

Using Growth Forms to Predict Epiphytic Lichen Abundance in a Wide Variety of Forest Types

Epiphytic richness is continuously declining due to forest fragmentation, logging, burning, agriculture, and livestock. The rate of species loss caused by habitat degradation and loss is more pronounced in Central and South America. Considering the extreme difficulty and time required to identify the more inconspicuous species, rapid diversity assessment methods need to be extrapolated throughout the world. This study correlated lichen growth forms and total epiphytic abundance across 119 forests located in Europe and Central-South America. A total of 54 papers were selected from specific databases focused on lichens. Additionally, data from several unpublished ecological studies were included. Linear regression models showed that epiphytic lichen abundance was highly and positively correlated with the number of growth forms at all geographical levels considered (i.e., Central-South American and European forests, and the combination of both). Thus, the use of growth forms may provide an alternative and complementary way to evaluate epiphytic diversity because most growth forms have cosmopolitan distribution and are easily recognizable.

Using Lichenometry, Dendrochronology, and Historical Data to Establish the Relative Age of an Abandoned Cemetery in Northern Arkansas

Folklore surrounding an abandoned cemetery located in Johnson County, Arkansas (a part of the Louisiana Purchase) suggested that it was used by early settlers. Historical records were combined with several dating techniques to determine the approximate time periods that Cedar Grove Cemetery was established and abandoned. Cores extracted from trees located adjacent to or on graves provided evidence that the cemetery was abandoned in the 1920s. These results coincide with the last burial event in 1922. The approximate age of undated gravesites was determined using lichenometry. A lichen growth rate of 0.0685 cm/year was determined for lichens present on two gravestones with known dates. This growth rate was then applied to the undated graves to establish their approximate ages. Death dates from historical records of individuals buried in the cemetery matched the dates established by the lichen growth rate. Our results show that many of the unmarked graves date prior to the first documented private ownership of the land. The results of this study support local folklore passed down over several generations about the origin of the cemetery.

A universal growth limit for circular lichens

Lichens fix carbon dioxide from the air to build biomass. Crustose and foliose lichens grow as nearly flat, circular disks. Smaller individuals grow slowly, but with small, steady increases in radial growth rate over time. Larger individuals grow more quickly and with a roughly constant radial velocity maintained over the lifetime of the lichen. We translate the coffee drop effect to model lichen growth and demonstrate that growth patterns follow directly from the diffusion of carbon dioxide in the air around a lichen. When a lichen is small, carbon dioxide is fixed across its surface, and the entire thallus contributes to radial growth, but when a lichen is larger carbon dioxide is disproportionately fixed at the edges of an individual, which are the primary drivers of growth. Tests of the model against data suggest it provides an accurate, robust, and universal framework for understanding the growth dynamics of both large and small lichens in nature.