Lichen Desert Research Articles

Initial stages of recovery of epiphytic lichen communities after reduction of emissions from a copper smelter

Analysis has been made of changes in the species composition and abundance of epiphytic lichens on fir trees during the first decade after a sharp reduction of emissions from a large copper smelter in the Middle Urals. The results show that lichens have recolonized the area of the former lichen desert and that the abundance of lichen species in the impact and buffer zones has increased. However, a fairly long time is required before lichen communities in the vicinity of the smelter can recover to the background state, since species highly sensitive to pollution still occur only in the background area.

Lichens of Sokółka (Podlasie, NE Poland) as indicators of the state of air pollution / Porosty Sokółki (Podlasie, Polska NE) jako wskaźniki zanieczyszczenia powietrza

Abstract Monitoring of lichens as bioindicators of air pollution has been conducted in Sokółka. On the basis of the occurrence of indicator epiphytic and epilithic lichen species, the scale of lichen sensitivity for the city has been developed and lichen zones have been designated. The zone pattern was not of insular character, and as a result there was no “total lichen desert”. The distribution of lichen zones reflects the intensity of anthropogenic pressure within the town. The least favourable conditions for lichen growth have been recorded in the town centre, while the green areas have shown the most beneficial impact on the lichen test sites

The lichen flora as bioindicator of air pollution of Gdańsk, Sopot and Gdynia

Four zones of lichen occurrence have been distinguished in Gdańsk, Sopot and Gdynia (N Poland). They are: 1) a total lichen desert zone, 2) a relative lichen desert zone, 3) a stunted growth zone, 4) a normal growth zone. Four groups of indicator species have been distinguished — they enable one to identify and characterize the lichen growth zones and the boundaries between them. Changes in the boundaries of the lichen growth zones have been predicted on the basis of the results of this study. 269 lichen species have been recorded from the study area, of which 183 have been discovered or refound during the present survey.

Water availability modifies tolerance to photo-oxidative pollutants in transplants of the lichen Flavoparmelia caperata

The hypothesis that a daily water supply allows a lichen to endure the negative effects of environmental concentrations of NO(x) and O(3) was tested with a transplant experiment. Five groups (0, A-D) of Flavoparmelia caperata samples derived from the same thalli were used for destructive, pre-exposure measurements (0), or exposed for 5 weeks in the rural collection site (A), and in a urban site with high levels of NO(x) and O(3) (B-D). Two groups (C, D) were daily watered half an hour before the daily peak of NO(x) (C), and O(3) (D). The comparison between pre- and post-exposure measurements of stress biomarkers revealed that the different thallus hydration regime modified the pollution tolerance as well as the physiology of the exposed samples. The non-watered group B suffered an evident decrease in F(v)/F(m) and reduced glutathione, but increased ion leakage, whereas the watered groups C and D showed only decreased non-photosynthetic-quenching, possibly derived from NO(x) exposure. Ozone, which was higher in the rural than in the urban site, did not significantly affect the lichen metabolism. Our results re-open the discussion on the so-called "drought hypothesis", which suggests that the lichen desert observed in urban areas of central and eastern Europe is more a matter of dry microclimate than of air pollution.

Air quality monitoring system using lichens as bioindicators in Central Argentina

Air quality studies with bioindicators have not been well developed in South America. In the city of Córdoba, there are not permanent air pollutant measurements by equipment. In order to develop an air quality biomonitoring system using lichens, we applied a systematic sampling in the city of Córdoba, Argentina. A total of 341 plots were sampled in the area of the city which is a square of 24 × 24 km. In each sample plot we selected three phorophytes and estimated the frequency and cover of lichen species growing at 1.5 m on trunks. We also calculated the Index of Atmospheric Purity (IAP) using lichen frequencies. Maps with number of lichen species, cover values, and IAP were performed. The lichen community was described with nine species where Physcia undulata and Physcia endochryscea were the most frequent. Moreover, these two species were dominant in the community with the highest cover index. The central area of the city is considered a lichen desert with poor air quality. The southeast and northwest areas of the city showed the highest IAP values and number of species. In general, the city shows fair air quality and few areas with good and very good air quality.

Lichen recolonisation in an urban-industrial area of southern Poland as a result of air quality improvement

Dynamics of epiphytic lichen distribution and diversity in the town of Skawina, one of the major industrial centres of southern Poland, over the last 30 years, was documented in relation to air quality changes. Fieldwork was conducted in 2006-2007. A total of 34 species were recorded at 202 sites, which is similar to the historical data, however, significant qualitative changes occurred. Nitrogen- and dust-tolerant species have expanded and dominate, while some acidophytes, such as Lecanora conizaeoides, are in decline. Lichens have recolonised the former 'lichen desert' in the town centre. Species richness at study sites has increased; and an improvement in the health of lichen thalli was noted. These trends reflect air quality improvement, mainly SO(2) decline in the last few decades and transport-related compounds, mainly NO(x) and dust that have became the main pollutants. Host tree species and diameter diversity also contribute significantly to lichen species diversity in the study area. The recolonisation process seems far from complete and further changes in the lichen distribution and diversity in the study area are expected.

Lichens as bioindicators of air quality in Dimitrovgrad (South-Eastern Serbia)

Air pollution detection in Dimitrovgrad has not been done yet. In this work different lichen have been used as a bioindication to establish different air pollution levels. At 18 investigated points 22 lichen taxa have been found. Using the Index of Atmospheric Purity (IAP) it has been found that there are 3 different air pollution zones in Dimitrovgrad: 'lichen desert', 'transitional' and 'normal zone'. The most sensitive lichen taxa in Dimitrovgrad are Evernia prunastra, Ochrolechia pallescens, Parmelia sulcata, and Physcia tenella and the most tolerant are Phaeophyscia orbicularis, Physcia adscendens, Physconia distorta, Physconia grisea, and Xanthoria parietina. .

Determination of Airpolution Zones in Knjaževac (South Eastern Serbia) by using Epiphytic Lichens

ABSTRACTAirpollution investigations have not been done in Knjaževac until now. In this work, method of bioindication by lichens has been used. On 18 investigated points it has been found 22 lichen taxa from 12 genera. By calculating Index of Atmospheric Purity (IAP) 2 zones with different air pollution (”lichen desert” and “transitional” zone) has been found. The most sensitive species in Knjaževac are Buelia punctata, Melanelia acetabulum, M. exasperata, and Parmelia tiliacea and most tolerant are Lecanora alophana, L. intumescens, L. pulicaris, Lecidella elaeochroma and Phaeophyscia orbicularis.

Monitoring of the “lichen desert” in the Belgrade area (1980/81, 1991 and 2007)

This paper treats long-term changes in area of the ?lichen desert?, i.e., the region characterized (especially in the winter period) by average daily SO2 concentration exceeding 150?g/m3 of air, the maximum allowable concentration (MAC) for populated regions. Comparison of results obtained in 1980/81 and 1991 indicates that the ?lichen desert? expanded (from 12 to about 13 km2) as a consequence of deterioration of the air quality in the Belgrade area. Comparing the results obtained in 1991 with investigations carried out in 2007, we found that ?lichen desert? shrank substantially in the Belgrade area to a current size of about 11 km2. The new boundaries of the ?lichen desert? are presented, together with the main reasons for its shrinkage in the Belgrade area during the last 16 years and predictions of further alterations in the future.

Epiphytic lichens as indicators of environmental quality in Rome

A synthesis of the studies on lichen diversity carried out in Rome over the period 1982–2003 is presented. In this work, the Lichen Diversity (LD) method has been applied. Besides air pollution, the most important variable affecting the epiphytic lichen flora of Rome, currently updated to 102 taxa, is the influence of the Tyrrhenian Sea. Significant changes in the lichen flora have been noted over the past 20 years, with the lowest diversity now being found in the urban centre and in the eastern and southern sectors, while the “lichen desert” area has decreased in parallel with decreasing concentrations of CO, NO x and SO 2.

Biodiversity of epiphytic lichens and heavy metal contents of Flavoparmelia caperata thalli as indicators of temporal variations of air pollution in the town of Montecatini Terme (central Italy)

The results of a biomonitoring survey carried out in the town of Montecatini Terme (central Italy) in the period 1993–2000 using the biodiversity of epiphytic lichens and the accumulation of heavy metals in thalli of Flavoparmelia caperata as indicators of air pollution are reported. From 1993 to 2000, the mean ILD value for the whole study area increased from 18±18 to 42±22, the lowest ILD value increased from 0 to 11 and the highest ILD value increased from 67 to 84. A ‘lichen desert’ was found only in 1993 and stations classified as ‘natural’ were lacking only in 1993 and 1996. Concentrations of all heavy metals decreased from 1993 to 1999. It is concluded that vehicular traffic is the main source of atmospheric pollution in the study area. The most likely changes that may have caused lichen communities to improve and heavy metals to drop is conversion of heating systems to methane (abatement of SO 2) and the use of unleaded gasoline (reduction of Pb). The present results showed that despite their slow growth rate, lichens respond rapidly to decreasing concentrations of air pollutants, allowing annual changes to be detected.

Using of epiphytic lichens for bioindication of air pollution in Vranje

Epiphytic lichens were used dor bioindication of air pollution in the city of Vranje for the first time. In 43 investigated places, the authors established the presence of 38 lichen taxa from 20 genera. By calculating the index of atmospheric purity (IAP), they established three zones with different air pollution levels (a "lichen desert zone", a "transitional zone", and a "normal zone") and two subzones (a "narrow transitional zone", and a "wider transitional zone"). The species Melanelia exasperatula, M. glabra, Lecanora allophana, Lecidella elaechroma, Ochrolechia sp, Ramalina sp., and Parmelina quercina were established as the most sensitive. On the other hand, Phaeophyscia orbicularis, Xanthoria parietina, and Parmelia sulcata were the most tolerant.

Diversity of epiphytic lichens and metal contents of Parmelia caperata thalli as monitors of air pollution in the town of Pistoia (c Italy).

The results of a biomonitoring survey carried out in the town of Pistoia (central Italy) using the biodiversity of epiphytic lichens and the accumulation of heavy metals in thalli of Parmelia caperata as indicators of air pollution are reported. Compared to previous surveys, the overall situation generally improved, with higher lichen diversity at most stations and lower metal concentrations in P. caperata thalli. However, the general picture according to a calibrated sale of environmental naturality/alteration was substantially negative, with about 87% of the study area classified as 'altered' (including the lichen desert) or 'semi-altered'. To explain this apparent contradiction, it has been suggested that lichen colonization is determined by declining SO2 concentrations, while major injuries to lichen communities are caused by the constantly high levels of NOX. In spite of the low levels of Pb measured in P. caperata thalli, vehicular traffic was excluded as the main source of atmospheric pollution. Domestic heating seems to be the main case of changes in the diversity of epiphytic lichens in the study area.

Temporal variation of air pollution in a geothermal area of central Italy: Assessment by the biodiversity of epiphytic lichens

The results of a biomonitoring survey carried out in the geothermal area of Travale-Radicondoli (central Italy) are reported. The aim of the study was to evaluate the temporal variation of air pollution from 1992 to the present, based on the actual biodiversity of the epiphytic lichens compared with that of a previous study in the same area. Although instrumental measurements were not available, it was assumed that variations in the biodiversity mostly reflected changes in the air pollution status. Furthermore, adopting a before-after strategy, the impact of a sansa oil extraction plant built in 1993 was also evaluated. The results showed that after 8 years, the geothermal area of Travale-Radicondoli is undergoing a gradual process of improvement, as clearly indicated by the colonization of some species in areas previously affected by the lichen desert;. The surroundings of the geothermal power plants did not show evident changes from the previous study, as the biodiversity values remain...

The effect of large anthropogenic particulate emissions on atmospheric aerosols, deposition and bioindicators in the eastern Gulf of Finland region

The effect of the emissions from large oil shale fuelled power plants and a cement factory in Estonia on the elemental concentration of atmospheric aerosols, deposition, elemental composition of mosses and ecological effects on mosses, lichens and pine trees in the eastern Gulf of Finland region has been studied. In addition to chemical analysis, fly ash, moss and aerosol samples were analysed by a scanning electron microscope with an energy dispersive X-ray spectrometer (SEM/EDS). The massive particulate calcium emissions, approximately 60 kton/year (1992), is clearly observed in the aerosols, deposition and mosses. The calcium deposition is largest next to the Russian border downwind from the power plants and in south-eastern part of Finland. This deposition has decreased due to the application of dust removal systems at the particulate emission sources. At the Virolahti EMEP station approximately 140 km north from the emission sources, elevated elemental atmospheric aerosol concentrations are observed for Al, Ca, Fe, K and Si and during episodes many trace elements, such as As, Br, Mo, Ni, Pb and V. The acidification of the soil is negligible because of the high content of basic cations in the deposition. Visible symptoms on pine trees are negligible. However, in moss samples close to the power plants, up to 25% of the leaf surface was covered by particles. Many epiphytic lichen species do not tolerate basic stemflow and on the other hand most species are also very sensitive for the SO 2 content in air. Consequently a large lichen desert is found in an area of 2500 km 2 in the vicinity of the power plants with only one out of the investigated 12 species growing.

Ecological condition of forests around the eastern part of the Gulf of Finland

The effects of air pollutants on forests around the eastern part of the Gulf of Finland were studied by measurement of the sulphur and calcium content of pine needles and evaluation of the ecological conditions of pine forests. Several parameters for pine trees and their needles were chosen as well as the species composition and condition of epiphytic lichens. Very high pine needle S- and Ca-contents were measured in the vicinity of the Narva and Slantsy plants. In this region both the acid and basic pollutant load is massive, partly neutralizing each other. It is suggested that the total load will, sooner or later, cause unexpected environmental damage. Wide ‘lichen desert’ areas were detected around Narva and Slantsy. Near the margins of these areas extraordinary epiphytes on pines were observed namely Xanthoria parietina (L.) Th.Fr. and red-coloured green alga Trentepohlia umbrina. They are regarded as indicators of alkaline pollution. The lowest pine needle S- and Ca-contents of the study area were measured in south-eastern Finland. The condition of pine forests and their needles was, however, better on the neighbouring Karelian Isthmus although the species number of epiphytic lichens was very low and the condition of the lichens was poor. It is suggested that these most sensitive indicators of air pollutants are damaged by pollutants from St Petersburg and Narva. Vast virgin forests of the Karelian Isthmus act as pollutant sinks reducing the effect of pollutants on trees. On the Finnish side intensive forest management has been carried on for many decades making forests and trees more sensitive to pollutants.

Ecosystem recovery after emission reductions: Sudbury, Canada

A case history is presented describing the ecosystem changes that accompanied the nearly 90% reduction of SO2 and metal particulate emissions from Sudbury smelters during the past 25 years. The instances of severe ground-level fumigations that caused acute damage to vegetation in an area of approximately 1,000 km2 have been nearly completely eliminated. Significant improvements in water quality have also occurred in many of the estimated 7,000 acid-damaged lakes. Several species of acid-sensitive phytoplankton, Zooplankton and insects have invaded lakes where improvements have occurred. Epiphytic lichens have reinvaded the former “lichen desert” that once extended out 7 km from the smelters. Sensitive species such as Evernia mesomorpha and Usnea hirta now exist throughout the area. The vascular plant communities have been relatively slow to recover in the most severely damaged terrestrial areas. Metal-tolerant grasses (e.g. Agrostis scabra. Deschampsia caespitosa) were the first species to invade the barrens. Acid- and metal-contamination of soil, severe microclimate conditions, and the damaging effects of insect pests appear to delay recovery of terrestrial ecosystems. Recovery rates of aquatic ecosystems are also affected by a suite of physical, chemical and biotic interactions and many lakes remain severely damaged.

Assessment of The Effects of Sulfur Dioxide (SO2) on Lichens Using Energy Dispersive X-Ray Spectroscopy

Lichens which are ubiquitous plants composed of a symbiont fungus and alga have been known for years to be sensitive bioindicators of air pollutants. Their presence has been used as an index of atmospheric purity. It is thought that sulfur dioxide (SO2) is the prime cause for the disappearance of lichens from urban areas (a lichen desert). Air quality can be monitored by observing the deterioration of lichen flora by their ability to absorb pollutants efficiently. Although certain pollutant-sensitive species do not readily demonstrate macroscopic changes in early stress situations, monitoring of photosynthetic capabilities and chlorophyll content have been used as a measure of subtle metabolic changes. Concomitant with a reduction in photosynthesis, an intracellular loss of potassium (K+) has been noted.

Lichens as indicators of air pollution in a steel producing town in South Wales

The lichen flora of a given region depends upon a multiplicity of factors. Some factors act directly or indirectly upon the lichen thallus; in addition the lichen thallus is capable, to some extent at least, of exerting a modifying influence upon the macro- and micro-environment. The polluted centre of Port Talbot, a steel town, has a restricted number of crustose and rather depauperate species. This ‘lichen desert’ is quite small possibly because either (a) the atmosphere is not heavily polluted, or (b) there is a rapid dilution of pollutants. With distance away from Port Talbot there is an increase in the number of lichen species and a change in the proportion of the various growth forms. Abutting the ‘lichen desert’ is a zone in which Parmelia sulcata, P. saxatilis, Cladonia coniocraea, and C. fimbriata are the most widely represented species. This is followed by a further zone dominated by Usnea comosa, U. florida, Cetraria glauca, and Cladonia impexa in particular. It must be noted that these zones are not clearly defined; there is a gradation in growth forms and a gradual change in the abundance of various species.