Terricolous Research Articles

Bryophyte Flora of Uganda. 8. Orthotrichaceae Part 1 – Macromitrioideae

(2008). Bryophyte Flora of Uganda. 8. Orthotrichaceae Part 1 – Macromitrioideae. Journal of Bryology: Vol. 30, No. 3, pp. 201-207.

The effect of traditional management burning on lichen diversity

AbstractQuestion: How does regular management burning of a northern, Calluna vulgaris‐dominated heathland affect the lichen diversity at the patch and landscape scale?Location: Mar Lodge Estate, Scottish Highlands, United Kingdom.Methods: 26 fire sites of different ages and 11 long‐term unburnt stands were surveyed to create a chronosequence of changing lichen diversity following burning. Data were analysed graphically, with a GLM and using a CCA.Results: Though the immediate effect of fire was to significantly reduce lichen diversity, it generally recovered within 20 years. There was a significant difference in the population dynamics between wet and dry moorland areas with terricolous lichens in the former site being replaced by pleurocarpous mosses. Older stands, unburnt for 25 years or more, generally had lower diversity than stands 10 to 15 years old. Changes in lichen diversity and community composition can be attributed to the development of Calluna stand structure following burning.Conclusions: Fire can be seen to play an important role in maintaining the diversity of lichens in heathland areas by providing a variety of stand‐structures and ages across the landscape that favours the development of greater beta‐diversity.

The influence of competition between lichen colonization and erosion on the evolution of soil surfaces in the Tabernas badlands (SE Spain) and its landscape effects

Badlands often contain a mosaic of soil surface types with contrasting hydrological behaviour which drives their short term geomorphic evolution. The Tabernas badlands, in semiarid SE Spain, show a complex mosaic of bare ground, biological soil crusts and plant covered patches, and high variability of covers and morphologies. Previous work has identified the surfaces that act as sources of runoff and sediments and those that act as sinks; the pathways of runoff between surfaces, and the runoff and erosion at catchment scale. However, surfaces without vascular plants, can be quite dynamic, with important effects on geomorphic processes. This work aims to generate hypotheses about the dynamics of both bare soil (34% of the area) and biological soil crusts (33%), and to provide a first estimation of the growth rate of terricolous lichens (as increase of coverage) and their geomorphological implications. The dynamics of ten representative soil surfaces were photographically monitored over 13 years, recording the cover and pattern of bare soil and of the two main kinds of biological soil crust: ‘brown crust’ and ‘white crust’. Erosion/deposition were measured by erosion pins in unbounded plots, and the hydrological and erosional behaviour monitored in bounded plots under natural and simulated rainfall. Biological colonization and crust growth were studied from 2004 within cleared plots in four crust communities. Microclimate was continuously monitored in each community. After 13 years, net erosion was recorded only in previously eroded slopes and divides. Vegetated sites and those covered by biological soil crust remained more or less invariant or recorded sedimentation. In all white crust surfaces, whole crust cover increased by 3% on average, while macrolichen cover increased by nearly 30%. Within the driest brown crust, macrolichen cover increased by 7%, while the whole crust decreased by 3%. According to previous work, lichen cover, particularly of white crust, is often greater in north to east facing orientations because of the higher slope stability and the longer duration of moisture. However, the increase of the whole biological soil crust can depend more on species composition and previous cover and less or not at all on the aspect, although certain species do grow faster in particular orientations. Within the plots cleared in 2004 the greatest increase occurred in the pioneering brown crust, which reached an average of 26% cover after one year, in spite of it receiving the most insolation. Significant microclimatic differences exist among the communities, mainly in radiation, soil moisture and thallus surface temperature. Terricolous lichen crusts, primary colonizers of bare, sufficiently stable areas, can grow quickly and, by increasing soil stability and development and modifying surface hydrology, they can influence surface dynamics and ultimately landform dynamics. Crust growth rate probably decreases as its cover increases and it probably also oscillates with microclimatic oscillations. However, the high potential growth rate recorded allows detection not only of climatic changes but also short term (possibly seasonal) periods of stability. Extensive lichen crusts indicate low erosion rates and particular climatic conditions; variations of crust cover could indicate climatic (or land use) variations.

Diversity and distribution of lichens in relation to altitude within a protected biodiversity hot spot, north-east India

Abstract:A study of the diversity and distribution of lichens at 10 sites within the Mehao Wildlife Sanctuary in Arunachal Pradesh, India, revealed 177 species, belonging to 71 genera and 35 families. The Sanctuary exhibited almost all the habit and habitat groups of lichens within its climatically heterogenous and altitudinally (400–2700 m) varied landscape. Among the different habitat groups, obligately corticolous lichens were dominant (133 species), followed by facultatively corticolous lichens (occurring on both rock and bark; 25 species), saxicolous lichens (17 species) and terricolous lichens (2 species). The corticolous habitat group was dominated by crustose species while saxicolous and terricolous groups were made up of mostly fruticose species. A substantial number of species (77) occurred at single sites only, and each of the 10 sites supported a distinct lichen assemblage. Altitude and humidity were the putative key factors controlling the diversity and distribution of lichens within the Sanctuary. The mid altitude range 1400–1600 m had the greatest lichen diversity, which showed a unimodal pattern in relation to altitude.

Susceptibility to acidic precipitation contributes to the decline of the terricolous lichens Cetraria aculeata and Cetraria islandica in central Europe

The effective quantum yield of photochemical energy conversion in photosystem II (Φ 2) was shown to be reduced in the terricolous lichens Cetraria aculeata and Cetraria islandica by short-term exposure to aqueous SO 2 at pH values occurring in the precipitation of areas with high SO 2 pollution. Significant reduction of Φ 2 was found at pH ≤ 3.3. At pH 2.8, Φ 2 was close to zero and did not recover within 24 h. This suggests that sensitivity to SO 2 (primarily associated with epiphytic lichens in the past) has contributed to the decline of both species in central Europe. In C. islandica, but not in C. aculeata, thalli with the natural content of lichen substances were more tolerant to SO 2 than thalli where the extracellular lichen substances were extracted before the experiment. This supports published results that the depsidone fumarprotocetraric acid, a major lichen substance of C. islandica, increases the pollution tolerance in lichens.

Perceived and Measured Levels of Environmental Pollution: Interdisciplinary Research in the Subarctic Lowlands of Northeast European Russia

Using interdisciplinary field research in the Usa Basin, northeast European Russia, we compared local inhabitants' perception of environmental problems with chemical and remote-sensing signatures of environmental pollution and their local impacts. Extensive coal mining since the 1930s around Inta and Vorkuta has left a legacy of pollution, detected by measuring snowpack, topsoil, and lichen chemistry, together with remote-sensing techniques and analysis of lake water and sediments. Vorkuta and its environs suffered the worst impacts, with significant metal loading and alkalization in lakes and topsoils, elevated metals and cations in terricolous (reindeer) lichens, and changes in vegetation communities. Although the coal industry has declined recently, the area boasts a booming oil and gas industry, based around Usinsk. Local perceptions and concerns of environmental pollution and protection were higher in Usinsk, as a result of increased awareness after a major oil spill in 1994, compared with Vorkuta's inhabitants, who perceived air pollution as the primary environmental threat. Our studies indicate that the principal sources of atmospheric emissions and local deposition within 25 to 40 km of Vorkuta were coal combustion from power and heating plants, coal mines, and a cement factory. Local people evaluated air pollution from direct observations and personal experiences, such as discoloration of snow and respiratory problems, whereas scientific knowledge played a minor role in shaping these perceptions.

Increased soil nitrogen associated with dinitrogen‐fixing, terricolous lichens of the genus Peltigera in northern Minnesota

Dinitrogen (N2)‐fixing lichens (cyanolichens) have long been recognized as a source of exogenous N in various ecosystems, yet the effects of nitrogen inputs from these lichens have been little studied. Cyanolichens of the genus Peltigera Willd. are often the dominant members of the earth‐dwelling (terricolous) cyanolichen community. They occur in diverse habitats around the globe, but no studies of their influence on soil N have been reported.We conducted field and laboratory investigations with the primary objective of determining whether soil N availability is increased near healthy thalli of terricolous dinitrogen‐fixing lichens. We measured available soil N in situ with ion‐exchange resin bags, potentially mineralizable N with laboratory incubations, total soil N, and soil temperature. Measurements were taken along transects that extended away from thalli of Peltigera, perpendicular to and parallel to topographic contours. Studies were conducted in ten types of forest across northern Minnesota, including two contrasting sites that represent extremes of habitat for Peltigera.Soil N availability, potentially mineralizable N, and soil %N increased significantly with proximity to healthy thalli of Peltigera (P‐values<0.05). Moreover, potential N mineralization was highly correlated with soil %N (R2=0.765). Our results suggest a potential zone of influence that extends 1.5 m from thalli of Peltigera. The data indicate that soil temperature is not a primary factor in these associations.

The influence of multi‐scale environmental variables on the distribution of terricolous lichens in a fog desert

AbstractQuestion:How do environmental variables in a hyper‐arid fog desert influence the distribution patterns of terricolous lichens on both macro‐ and micro‐scales?Location:Namib Desert, Namibia.Methods:Sites with varying lichen species cover were sampled for environmental variables on a macro‐scale (elevation, slope degree, aspect, proximity to river channels, and fog deposition) and on a micro‐scale (soil structure and chemistry). Macro‐scale and micro‐scale variables were analysed separately for associations with lichen species cover using constrained ordination (DCCA) and unconstrained ordination (DCA). Explanatory variables that dominated the first two axes of the constrained ordinations were tested against a lichen cover gradient.Results:Elevation and proximity to river channels were the most significant drivers of lichen species cover in the macro‐scale DCCA, but results of the DCA suggest that a considerable percentage of variation in lichen species cover is unexplained by these variables. On a micro‐scale, sediment particle size explained a majority of lichen community variations, followed by soil pH. When both macro and micro‐scale variables were tested along a lichen cover gradient, soil pH was the only variable to show a significant relationship to lichen cover.Conclusion:The findings suggest that landscape variables contribute to variations in lichen species cover, but that stronger links occur between lichen growth and small‐scale variations in soil characteristics, supporting the need for multi‐scale approaches in the management of threatened biological soil crust communities and related ecosystem functions.

The influence of multi-scale environmental variables on the distribution of terricolous lichens in a fog desert

Abstract Question: How do environmental variables in a hyper-arid fog desert influence the distribution patterns of terricolous lichens on both macro- and micro-scales? Location: Namib Desert, Namibia. Methods: Sites with varying lichen species cover were sampled for environmental variables on a macro-scale (elevation, slope degree, aspect, proximity to river channels, and fog deposition) and on a micro-scale (soil structure and chemistry). Macro-scale and micro-scale variables were analysed separately for associations with lichen species cover using constrained ordination (DCCA) and unconstrained ordination (DCA). Explanatory variables that dominated the first two axes of the constrained ordinations were tested against a lichen cover gradient. Results: Elevation and proximity to river channels were the most significant drivers of lichen species cover in the macro-scale DCCA, but results of the DCA suggest that a considerable percentage of variation in lichen species cover is unexplained by these variable...

Syntaxonomy of arctic terricolous lichen vegetation, including a case study from Southeast Greenland

Syntaxonomy of arctic terricolous lichen vegetation, including a case study from Southeast Greenland

An assessment of pollution impacts due to the oil and gas industries in the Pechora basin, north-eastern European Russia

Abstract The chemical composition of terricolous lichens, top-soil and abundance and diversity of lichen communities were assessed at eight sites in the Pechora basin during the summer of 2000 and 2001 to assess local impacts of oil and gas operations. Sites close to industrial areas were compared with areas considered to be pristine. The broad objective of the study was to identify changes in the chemistry of a suite of lichens that could be caused by pollutants from the industrial sites. In particular, increases in the ratios of K:Mg and K:Ca + Mg are indicators of acid deposition and increased N indicates increased N deposition. Lead was also measured in lichens. Other elements measured were Ba, Ca, Cd, Cu, K, Mg, Na, Ni, Pb, Sr and Zn in top-soils. The Pechora basin, north-eastern European Russia, includes the north and east of the Komi Republic and a major portion of the Nenets Autonomous region. It is bounded by the Ural mountains to the east and by the Timan range to the west. The area has extensive natural resources, both renewable (e.g. forests) and non-renewable (e.g. minerals, coal, oil and gas). There were limited modifications in the chemistry of lichens and top-soils and lichen diversity close to an oil and gas industrial complex. Here, there were elevations of lead and nitrogen concentrations in lichen apices and in the apical:basal nitrogen ratio in Flavocetraria cucullata , with lower lichen diversity in epigeal and epiphytic lichens. Elevated concentrations of Ba and Ca were found in soil-ash over the 0–5 cm horizon, probably as a result of local emissions from construction activity and gas flaring, rather than from long-range transport. Virtually all other sites remained unmodified and reflected background concentrations. The ecological impacts of the measured pollution loads were low, as elemental concentrations were generally below detection limits, except for one industrial site, where there were signs of an early indicator of industrial activity.

Terricolous lichens in the northern Namib Desert of Namibia: distribution and community composition

Terricolous lichens are the dominant vegetation in expansive areas of the Namib Desert, where fog is the main source of moisture and other vegetation is scarce. They play several important roles in soil crust stabilization and in the primary production of the Namib Desert ecosystem, yet little is known about the diversity and distribution of lichens in the northern unexplored regions of the Namib. To our knowledge, this study is the first survey of terricolous lichens to be carried out in the northern Namib Desert. Seven soil crust habitat types were identified in the study area, and a total of twenty-eight soil crust lichen species was recorded. The survey uncovered lichen species that may be unique to the northern Namib, including vagrant species, and common species were frequently found in a vagrant form. The crustose group was the most widely represented. Overall community compositions differed from those found in other regions of the Namib, and distribution patterns suggest a link to gravel clast size and physical soil crust type.

Soil-associated lichens in rangelands of north-eastern Patagonia. Lichen groups and species with potential as bioindicators of grazing disturbance

Soil-associated lichen species characteristic of north-eastern Patagonia are classified by cluster analysis into six groups using ecological and morphological characters. The constancy of species, the total number of species, the number of species per crust and the relative frequency of species are analysed at sites with different grazing levels: three non-grazed, three regulary grazed, and three heavily grazed. Using the results, the potential use of lichen groups as bioindicators of rangeland conservation and degradation are explored. Species of three lichen groups (group A: lichens growing on calcareous gravels; group C: terricolous lichens with pale, crustose non-areolate thalli; group F: terricolous lichens with pale, areolate thalli) are identified as sensitive to grazing, and most of the species forming these groups are suggested as potential bioindicators of grazing disturbance. Thus, Rinodina bischoffii, Caloplaca holocarpa, Catillaria lenticularis, Acarospora heppii (group A); Lecanora dispersa and Rinodina mucronatula (group C); and Psora decipiens (group F) are the species most sensitive to grazing disturbance. Conversely, species of group D (terricolous lichens with dark, foliose thallus: Collema coccophorum), and group B (lichens growing on siliceous gravels: Aspicilia contorta) may be indicated as the most resistant to grazing disturbance.

Cellular Impact of Metal Trace Elements in Terricolous Lichen Diploschistes muscorum (Scop.) R. Sant. – Identification of Oxidative Stress Biomarkers

The purpose of this research is to present toxic effects of some heavy metals (cadmium, lead and zinc) on lichen physiology. In the North of France, those metals are concentrated for example in industrial polluted soils near metallurgic plants and waste dumps. Our investigations were conducted on Diploschistes muscorum (Scop.) R. Sant, a terricolous lichen growing on previously quoted soils as well as on non-contaminated ones. Different stress parameters were investigated as potassium leakage – which is related to the loss of membrane integrity – and oxidative stress through following parameters: malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD). It seems, therefore, that heavy metals induce oxidative stress in this lichen, in which we found membrane damage and enhancement of SOD activity and GSH concentrations. With regard to very high concentrations of Cd, Pb and Zn, a resistance involving antioxidant mechanisms limits the expected damage. Those mechanisms involve GSH, SOD as well as secondary metabolites, which have this resistance property. This study is a first step of investigation to use – in the future– physiological parameters as tool for environment assessment.

Ecology of soil lichens from Pliocene clay badlands of central Italy in relation to geomorphology and vascular vegetation

The terricolous lichen communities occurring under a temperate sub-arid to sub-humid climate (mean annual rainfall about 750 mm) on Pliocene clay soils of southern Tuscany (central Italy) are similar to those reported for arid or sub-arid areas, with mean annual rainfall around 200 mm. The distribution of these communities is influenced by the availability of bare soil and percentage cover of vascular plants. Where vascular communities are more important and pedogenetic processes lead to the development of more structured and evolved soils, pioneer lichen communities of the Toninio-Psoretum decipientis are replaced by communities such as that of Cladonietum convolutae, which are more capable of competing for light and nutrients with dense communities of tall grasses such as Bromus erectus. The distribution patterns of Artemisia cretacea and B. erectus among vascular plants, and Fulgensia fulgens and Cladonia rangiformis among lichens, account for most of the variability in vascular and lichen communities, respectively.

Regional variation in the chemical composition of winter snow pack and terricolous lichens in relation to sources of acid emissions in the Usa river basin, northeast European Russia

The chemical composition of snow and terricolous lichens was determined along transects through the Subarctic towns of Vorkuta (130 km west–east), Inta (240 km south–north) and Usinsk (140 km, southwest–northeast) in the Usa river basin, northeast European Russia. Evidence of pollution gradients was found on two spatial scales. First, on the Inta transect, northward decreases in concentrations of N in the lichen Cladonia stellaris (from 0.57 mmol N g −1 at 90 km south to 0.43 mmol N g −1 at 130 km north of Inta) and winter deposition of non-sea salt sulphate (from 29.3 to 12.8 mol ha −1 at 90 km south and 110 km north of Inta, respectively) were attributed to long range transport of N and S from lower latitudes. Second, increased ionic content (SO 4 2−, Ca 2+, K +) and pH of snow, and modified N concentration and the concentration ratios K +:Mg 2+ and K +: (Mg 2++Ca 2+) in lichens ( Cladonia arbuscula and Flavocetraria cucullata) within ca. 25–40 km of Vorkuta and Inta were largely attributed to local deposition of alkaline coal ash. Total sulphate concentrations in snow varied from ca. 5 μmol l −1 at remote sites to ca. 19 μmol l −1 near Vorkuta. Nitrate concentration in snow (typically ca. 9 μmol l −1) did not vary with proximity to perceived pollution sources.

The lichen flora of unprotected soft sea cliffs and slopes

Soft unprotected sea cliffs and slopes were surveyed at forty localities around the English coast and found to support a restricted lichen flora that was zoned in relation to sea-level. Bed rock composition, structural heterogeneity and high levels of instability largely control the terricolous lichen vegetation, which is predominantly composed of calcicoles typical of early successional stages. Cyanobacterial lichens are well represented. The species encountered can be arranged into three provisional assemblages characteristic of alkaline bed rock, acidic bed rock, and turf edges. Few species with maritime affinities were present but this group included rarely recorded species of Pyrenocollema and abundant Lecanora zosterae. Other rare and unusual lichens were present, often at a low density and in only a few localities. The lichen flora of soft cliffs has links with that found on urban wasteland and, remotely, with that of sand dunes.

Growth of reindeer lichens and effects of reindeer grazing on ground cover vegetation in a Scots pine forest and a subarctic heathland in Finnish Lapland

Reindeer lichens are an important component of northern ecosystems. The aim of this study was to measure the growth rate of terricolous lichens as it is a key parameter involved in productivity of these ecosystems and an important part of lichen tolerance to reindeer grazing. Furthermore, the natural succession and the long‐term effects of reindeer grazing on lichen community characteristics in two contrasting habitats were investigated as well as the interactions between lichen cover and mosses and vascular plants. Biomass and coverage measurements were conducted in a lichen woodland and in a subarctic heath with grazed and ungrazed areas in northern Finland. Measurements spanning over 13 yr of undisturbed development show that the growth rate of Cladina stellaris can be as high as >0.17 g g−1 produced annually, although in average growth rates were much lower. During the succession of ground vegetation, C. stellaris, C. rangiferina, C. mitis and Cetraria nivalis increased in biomass in fenced areas and were reduced most in biomass by reindeer in unprotected areas. Reindeer grazing and trampling seem to change the vegetation towards a type that is dominated by small dwarf shrubs, bare soil and minute‐cup lichens (Cladonia spp.). Removing the lichen layer by reindeer may reduce natural regeneration of pine trees as implied by increasing numbers of pine seedlings with increasing lichen cover.

Water distribution within terricolous lichens revealed by scanning electron microscopy and its relevance in soil crust ecology

The effects of the structural features of the thallus and the lichen–substratum interface on soil water infiltration were investigated using low temperature scanning electron microscopy and scanning electron microscopy with backscattered electron imaging. Two morphologically different lichen species were examined, the crustose Diploschistes diacapsis and the squamulose Squamarina lentigera. Water distribution within lichen-forming soil crusts explains the results of earlier infiltration studies. Several anatomical features of the upper cortex gave rise to similar impervious characteristics of the thallus. The fungal material comprising the lichen thallus showed significant hydrophobic features and only when in contact with calcium oxalate crystals or minerals in the soil was this material able to retain water. The lichen–substratum interface appears to play an important role in the hydric strategy of these lichens which in turn affects the penetration of water into the soil.

Saxicolous and terricolous lichens from the foothills of northern Oman

To date, 36 species of lichens have been recorded from the Sultanate of Oman, a rather short list in view of the number of potential suitable habitats. During a field trip to the foothills of northern Oman, twenty-four morphologically distinct taxa were found, 20 of which have been positively determined to specific level. Seventeen of these species are new records for the country. The majority of species (13) are cyanobacterial lichens. Most species occurred on compacted soil, mainly in partially shaded habitats such as in crevices in rocks, but occasionally, some species were found in sun-exposed situations on open ground ( Heppia adglutinata ). A few species were found growing on limestone rock. All species recorded during this study have been found in various countries of the Arabian Peninsula, and a marked similarity is evident with the lichen flora of southern Yemen. Zusammenfassung: Bislang waren Vorkommen von lediglich 36 Flechtenarten aus dem Sultanat Oman bekannt. Die Zahl erscheint klein in Anbetracht der Vielfalt der potentiellen Lebensra ume. Im Zuge von Feldarbeiten im Hu gelland des no rdlichen Omans konnten nun 24 Flechten nachgewiesen und 20 davon bis zur Art bestimmt werden. 17 Arten sind Neufunde fu r das Sultanat Oman. Es dominierten cyanobakterielle Flechten. Bevorzugte Habitate waren Bodenkrusten in zum Teil be- schatteten Felslu cken. Gelegentlich wurden auch offene, sonnenexponierte Bodenkrusten besiedelt (Heppia adglutinata ). Einige wenige Arten kamen direkt auf Kalkstein vor. Alle Flechten, die im Rahmen der vorliegenden Studie gefunden wurden, waren bereits aus verschiedenen Teilen der Arabischen Halbinsel bekannt. Es bestehen v.a. aber markante U bereinstimmungen in der Arten- zusammensetzung mit der Flechtenflora des su dlichen Jemen.