Abstract: Abstract: There is evidence to suggest that part of the recent changes in the lichen flora of the Netherlands is attributable to an increase in temperature. Changes which have occurred over the last 22 years were studied in detail, and were subjected to a statistical treatment by comparing the change of species to their latitudinal distribution and to ecological determinants. All 329 epiphytic and terrestrial lichen species occurring in the Netherlands were considered in relation to their world distribution. Arctic-alpine/boreo-montane species appear to be declining, while (sub)tropical species are invading. The proportion of increasing species is by far the largest among the wide-tropical lichens (83%), and smallest among the arctic-alpine/boreo-montane lichens (14%). None of the wide-tropical species was found to decrease, while 50% of the arctic-alpine/boreo-montane species show a decline. Long-term monitoring of the epiphytic lichen flora in the province of Utrecht from 1979 onwards shows that the total number of taxa present increased from 95 in 1979 to 172 in 2001, while the average number of taxa per site increased from 7·5 to 18·9. The rate of increase was greatest by far between 1989 and 1995. The majority of the species (152 taxa or 85%) show a gross increase, only 17 species (10%) show a decrease. A detailed analysis of these data using multiple regression suggests global warming as an additional cause for recent changes, next to decreasing SO2 and increasing NH3. Changes appear to be correlated initially (1979–1995) only with toxitolerance and nutrient demand. Changes between 1995 and 2001, however, appear positively correlated to both temperature and nutrient demand, indicating a recent and significant shift towards species preferring warm circumstances, independent from, and concurrent with changes due to nutrient availability. This is the first paper reporting long-term floristic changes for lichens that appear to be correlated significantly with increasing temperatures. We suggest that future lichen monitoring programmes also pay attention to effects of climatic change, instead of focusing on air pollution effects only.

Abstract: Lichen symbioses represent a major way of life among the Fungi Almost one-fifth of all known fungal species are lichenized, and about 1500 species of lichens contain cyanobacterial photobionts, most of which belong to the genus Nostoc Despite extensive studies, many basic aspects of their biology remain poorly known, especially cyanobiont diversity and specificity ([1][1]) Cyanolichen specimens were collected from northern Europe, western North America, and central China Epiphytic lichen communities in two old-growth forests in central Finland were studied in detail (tables S1 and S2) Lichens were identified, and free-living cyanobacteria were cultured from substrate samples The small subunit (16 S ) of the ribosomal gene repeat and the tRNALeu (UAA) intron were sequenced from cyanobacterial DNA The 16 S rDNA sequences were used to resolve phylogenetic relationships, and the tRNALeu intron sequences were used for identifying Nostoc strains ([2][2]) Cyanobacterial 16 S rDNA sequences were obtained from 16 species of cyanolichens Additional sequences were acquired from cyanobacterial cultures and GenBank (table S1) A phylogenetic analysis of these sequences resulted in a consensus tree in which all Nostoc formed a monophyletic group with 100% support ([Fig 1][3]) The Nostoc clade was divided into two subgroups; the first only included cyanobionts of epiphytic lichen species ( Nephroma guild) Further subdivisions within this group did not correlate with the geographical origin or generic identity of the lichen specimens The second subgroup ( Peltigera guild) included cyanobionts of terrestrial lichens, free-living Nostoc strains, and a symbiotic Nostoc from the roots of a cycad ([Fig 1][3]) ![Figure 1][4] Figure 1 A strict consensus tree showing phylogenetic relationships among symbiotic and free-living cyanobacteria based on 16 S rDNA sequence data (table S1) Bootstrap support >50% is shown at nodes All Nostoc strains form a monophyletic group The cyanobionts of the Nephroma guild form a well-supported subgroup within the Nostoc clade The cyanobionts of the Peltigera guild group together with free-living Nostoc strains These groupings are congruent with data from tRNALeu (UAA) intron sequences (table S2) Most epiphytic cyanolichens in central Finland contained similar tRNALeu intron genotypes (table S2) One intron genotype was found from all six sample plots, and it was shared extensively by four different species of Nephroma and Parmeliella Two other intron genotypes differed from the most frequent intron genotype by only one base change each; these genotypes were found from several epiphytic lichens on different sample plots These and a fourth Finnish intron genotype shared the same repeat motif in their P6b element ([3][5]) Four North American and two Chinese intron genotypes also had this repeat motif As in Finland, all these sequences were obtained from epiphytic cyanolichens (table S2) A different set of tRNALeu intron genotypes was obtained from Peltigera thalli and cultured Nostoc strains (table S2) These sequences had a different repeat motif in the P6b element and could not be readily aligned with the sequences from epiphytic cyanolichens ([3][5]) Species of Peltigera are predominately terricolous, and when growing epiphytically, they are usually confined to mossy basal trunks Two intron genotypes were obtained by culturing thallus fragments of Lobaria pulmonaria Two North American and two Chinese intron genotypes had the same P6b repeat motif as Finnish Peltigera cyanobionts As in Finland, these sequences were amplified from different species of Peltigera and Lobaria (table S2) Although lichen mycobionts are selective in their choice of Nostoc symbionts, several fungi may often share identical cyanobiont strains ([1][1], [3][5], [4][6]) Our results demonstrate the full extent of this phenomenon and indicate that cyanolichens express their Nostoc specificity on a community scale Many cyanolichens associated with old-growth forests depend on a specific group of Nostoc strains that have not been found in other types of cyanolichens These epiphytes exploit a common pool of cyanobacteria and form a horizontally linked system, the Nephroma guild Conversely, many terrestrial cyanolichens share a different group of related Nostoc strains, thus forming the Peltigera guild The guild membership of Finnish Lobaria pulmonaria specimens remained unclear because of inherent uncertainties in identifying symbiotic Nostoc strains by using cultures North American L pulmonaria specimens belonged to the Nephroma guild ([Fig 1][3]) The dispersal ecology of cyanolichen guilds may center around “core species,” such as N parile and P triptophylla , that produce massive amounts of symbiotic diaspores “Fringe species,” such as N bellum and N resupinatum , produce only fungal spores and may largely depend on the core species for the dispersal of appropriate cyanobionts Only a small proportion of symbiotic propagules can develop into mature lichen thalli Many diaspores land on suboptimal substrates, eventually disintegrate, and release their cyanobionts These cyanobionts may be salvaged by the mycobionts of fringe species Core species may also benefit from this activity, as their cyanobionts are deposited into other guild members rather than being completely lost Some of the cyanobionts can potentially be reclaimed because, without the ability to produce symbiotic diaspores, fringe species cannot “grab the cyanobionts and run” These phenomena may help to explain why the existence of competition is often difficult to demonstrate in lichen communities ([5][7]) In addition to the two cyanolichen guilds discussed here, we have preliminarily identified several other cyanolichen guilds Similar systems may also operate among green algal lichens and other symbiotic systems, such as corals 1 [↵][8]J Rikkinen, in Cyanobacteria in Symbiosis , A N Rai et al , Eds (Kluwer Academic, in press) 2 [↵][9]Supporting material is available on Science Online 3 [↵][10]P Paulsrud, thesis, Uppsala University, Uppsala, Sweden (2001) 4 [↵][11]1 P Paulsrud 2 et al , New Phytol 152, 117 (2001) 5 [↵][12]1 J Rikkinen , Bryobrothera 4, 170 (1995) 6 We thank B McCune, K Sivonen, and P Lindblad for cooperation and help We are especially grateful to P Paulsrud, who has pioneered the use of molecular methods in the study of lichenized cyanobacteria Our research was supported by the Academy of Finland (project number 168 332) Supporting Online Material [wwwsciencemagorg/cgi/content/full/297/5580/357/DC1][13] Materials and Methods Tables S1 and S2 [1]: #ref-1 [2]: #ref-2 [3]: #F1 [4]: pending:yes [5]: #ref-3 [6]: #ref-4 [7]: #ref-5 [8]: #xref-ref-1-1 "View reference 1 in text" [9]: #xref-ref-2-1 "View reference 2 in text" [10]: #xref-ref-3-1 "View reference 3 in text" [11]: #xref-ref-4-1 "View reference 4 in text" [12]: #xref-ref-5-1 "View reference 5 in text" [13]: http://wwwsciencemagorg/cgi/content/full/297/5580/357/DC1

Abstract: Four filamentous cyanobacteria, Microcoleus vaginatus, Phormidium tenue, Scytonema javanicum (Kutz.) and Nostoc sp., and a single-celled green alga, Desmococcus olivaceus, all isolated from Shapotou (Ningxia Hui Autonomous Region of China), were batch cultured and inoculated onto unconsolidated sand in greenhouse and field experiments. Their ability to reduce wind erosion in sands was quantified by using a wind tunnel laboratory. The major factors related to cohesion of algal crusts, such as biomass, species, species combinations, bioactivity, niche, growth phase of algae, moisture, thickness of the crusts, dust accretion (including dust content and manner of dust added) and other cryptogams (lichens, fungi and mosses) were studied. The best of the five species were M. vaginatus and P. tenue, while the best mix was a blend of 80% M. vaginatus and 5% each of P. tenue,S. javanicum,Nostoc sp. and D. olivaceus. The threshold friction velocity was significantly increased by the presence of all of the cyanobacterial species, while the threshold impact velocity was notably increased only by the filamentous species. Thick crusts were less easily eroded than thin crusts, while biomass was more effective than thickness. Dust was incorporated best into Microcoleus crust when added in small amounts over time, and appeared to increase growth of the cyanobacterium as well as strengthen the cohesion of the crust. Microbial crust cohesion was mainly attributed to algal aggregation, while lichens, fungi and mosses affected more the soil structure and physico-chemical properties.

Abstract: Lichens from the genus Umbilicaria were collected across a 5,000-km transect through Antarctica and investigated for DNA sequence polymorphism in a region of 480–660 bp of the nuclear internal transcribed spacer region of ribosomal DNA. Sequences from both fungal (16 ascomycetes) and photosynthetic partners (22 chlorophytes from the genus Trebouxia) were determined and compared with homologs from lichens inhabiting more temperate, continental climates. The phylogenetic analyses reveal that Antarctic lichens have colonized their current habitats both through multiple independent colonization events from temperate embarkation zones and through recent longrange dispersal in the Antarctic of successful preexisting colonizers. Furthermore, the results suggest that relichenization— de novo establishment of the fungus-photosynthesizer symbiosis from nonlichenized algal and fungal cells—has occurred during the process of Antarctic lichen dispersal. Independent dispersal of algal and fungal cultures therefore can lead to a successful establishment of the lichen symbiosis even under harsh Antarctic conidtions.

Abstract: As a consequence of increasing greenhouse gas concentrations, climate change is predicted to be particularly pronounced, although regionally variable, in the vast arctic, sub-arctic and alpine tundra areas of the northern hemisphere. Here, we review winter foraging conditions for reindeer and caribou (Rangifer tarandus) living in these areas, and consider diet, forage quality and distribution, accessibility due to snow variation, and effects of snow condition on reindeer and caribou populations. Finally, we hypothesise how global warming may affect wild mountain reindeer herds in South Norway. Energy-rich lichens often dominate reindeer and caribou diets. The animals also prefer lichens, and their productivity has been shown to be higher on lichen-rich than on lichen-poor ranges. Nevertheless, this energy source appears to be neither sufficient as winter diet for reindeer or caribou (at least for pregnant females) nor necessary. Some reindeer and caribou populations seem to be better adapted to a non-lichen winter diet, e.g. by a larger alimentary tract. Shrubs appear to be the most common alternative winter forage, while some grasses appear to represent a good, nutritionally-balanced winter diet. Reindeer/caribou make good use of a wide variety of plants in winter, including dead and dry parts that are digested more than expected based on their fibre content. The diversity of winter forage is probably important for the mineral content of the diet. A lichen-dominated winter diet may be deficient in essential dietary elements, e.g. minerals. Sodium in particular may be marginal in inland winter ranges. Our review indicates that most Rangifer populations with lichen-dominated winter diets are either periodically or continuously heavily harvested by humans or predators. However, when population size is mainly limited by food, accessible lichen resources are often depleted. Plant studies simulating climatic change indicate that a warmer, wetter climate may cause an altitudinal upward shift in the production of mat-forming lichens in alpine, sub-arctic regions. This is due to an increased potential for lichen growth at high altitudes, combined with increased competition from taller-growing vascular plants at lower altitudes, where the biomass of Betula nana in particular will increase. Matforming lichens dominant on dry, windblown ridges are easily overgrazed at high reindeer densities. This has longterm effects due to lichens’ slow regeneration rate, but may also reduce competition from vascular plants in a long time perspective. Fires may act in a similar way in some forested areas. Accessibility of winter forage depends on plant biomass, snow depth and hardness; ice crusts or exceptionally deep snow may result in starvation and increased animal mortality. Calf recruitment appears to be low and/or highly variable where winter ranges are overgrazed and hard or deep snow is common. Population decline in several Rangifer tarandus spp. has been associated with snow-rich winters. Effects tend to be delayed and cumulative, particularly on calves. This is mainly ascribed to feeding conditions for young animals which later affect age at maturation. Global warming may increase the frequency of deep or hard snow on reindeer ranges in Norway, due to increased precipitation and more frequent mild periods in winter. We hypothesise that potential benefits from increased plant productivity due to global warming will be counteracted by shifts in the distribution of preferred lichen forage, reduction of the areas of suitable winter ranges, and generally reduced forage accessibility in winter.

Abstract: Abstract: In contrast to virtually all other species of ruminants, reindeer ( Rangifer tarandus ) eat substantial amounts of lichens in winter. Several different species of lichens are eaten and most are highly palatable. The chemical composition and the in vitro digestibility of six species of terricolous lichens commonly eaten by reindeer were measured. Ruminal inoculum was obtained in winter from six free-ranging reindeer that had been grazing on natural pastures in northern Norway. Analysis of the plant parts recovered from their rumens confirmed that the animals had been eating a mixed diet that included both lichens and vascular plants. The chemical composition and the in vitro digestibility of the different species of lichens varied considerably between species and genera. Cetraria islandica , C. nivalis and Cladonia arbuscula were highly digestible [69–77% dry matter (DM)], Stereocaulon paschale was poorly digestible (43% DM), whereas Cladonia stellaris and C. gracilis had an intermediate digestibility (56–57% DM). Mixing Cladonia stellaris with vascular plants (50:50) had no effect on the in vitro digestibility of the combined substrates. The in vitro digestibility of Cladonia stellaris in inoculum from two captive reindeer which had had no access to lichens was very low (10% DM). This shows that the source of inoculum used for digestibility trials has a major effect on the apparent digestibility of the substrates. Evidently, the extent to which reindeer are able to utilize lichens depends on the species that are selected and on what the animals have been eating recently.

Abstract: Biological soil crusts consisting of algae, cyanobacteria, lichens, fungi, bacteria, and mosses are common in habitats where water and nutrients are limited and vascular plant cover is discontinuous Crusts alter soil factors including water availability, nutrient content, and erosion susceptibility, and thus are likely to both directly and indirectly affect plants To establish this link, we must first understand the crust landscape We described the composition, abundance, and distribution of microalgae in crusts from a periodically burned, xeric Florida shrubland, with the goal of understanding the underlying variability they create for vascular plants, as well as the scale of that variability This is the first comprehensive study of crusts in the southeastern United States, where the climate is mesic but sandy soils create xeric conditions We found that crusts were both temporally and spatially heterogeneous in depth and species composition For example, cyanobacteria and algae increased in abundance 10-15 years after fire and away from dominant shrubs Chlorophyll a levels recovered rapidly from small-scale disturbance relative to intact crusts, but these disturbances added to crust patchiness Plants less than 1 m apart can experience different crust environments that may alter plant fitness, plant interactions, and plant community composition

Abstract: Scientists and land managers have been concerned about the state of forest lichens for many years. Most of the studies published during the last 100 years on lichens and pollution (e.g. reviews [49, 65] and section 1, this volume) have involved lichens on trees, and many studies have investigated forest lichen communities. In the last 50 years, concern about the loss of lichen diversity in connection with forest management and forest fragmentation has led to many studies designed to assess patterns and monitor trends of lichen biodiversity in forests worldwide (e.g. reviews [2, 82]). Recognition of the regional, continent-wide, and even global scale of adverse impacts on lichen communities has fostered studies and monitoring efforts designed to assess the impact of multiple factors adversely affecting forest lichen communities at large scales [43].

Abstract: This experimental study focuses on why old-forest lichens such as Lobaria scrobiculata and Platismatia norvegica are scarce in younger spruce stands. Understanding the factors limiting the distribution of species is important for developing appropriate methods for forest management aiming to maintain biodiversity. A successful growth of L. scrobiculata and P. norvegica was found in the young planted stand as the rate of growth did not differ between the young stand and the old spruce forest where they naturally occurred, during 14 months of transplantation. In the young forest environment, L. scrobiculata showed a significantly higher specific thallus weight, and a slightly higher water-holding capacity. This morphological response is probably due to a higher light exposure in the young stand and consequently a higher rate of desiccation. The ubiquitous species Platismatia glauca showed a significantly higher rate of growth in the young forest than in the old forest, and a positive relationship between growth rate and light exposure was found. This transplant study has shown that the environmental conditions in younger planted forests are not necessarily unfavourable for growth of old-forest lichens. Other factors, such as limited dispersal ability and poor diaspore production, are probably important for explaining the species scarcity in younger stands.

Abstract: The lichens were irrigated with different N forms, enriched in 15N to assess N uptake, during 3 months in the field, with a total N dosage of 500 mg m−2. Nitrogen deprivation was induced by rem ...

Abstract: Summary • The main aims of this paper are to investigate: if widespread lichen species ( Xanthoria parietina , Physconia grisea and Physcia adscendens , collected in Italy and Poland) exposed to cadmium (Cd), lead (Pb) and zinc (Zn) synthesize phytochelatins; whether phytochelatins are synthesized by the heterotrophic fungus (mycobiont) or by the photosynthetic alga (photobiont), or by both of the partners; and if there are significant differences in phytochelatin production in the same lichen species growing at different latitudes. • In the lichens investigated, Cd, Pb and Zn induced the biosynthesis of phytochelatins (PC 2 , PC 3 and PC 4 ) and some DES-GLYCIL derivatives. However, only the photobiont partners (the green microalgae of the genus Trebouxia ) were capable of phytochelatin production and, by contrast, aposymbiotically grown mycobionts only produced glutathione. • The Cd-exposed lichens grown in Italy produced significantly larger amounts of phytochelatins than the same species grown in Poland. An opposite trend was observed in Pb-exposed lichens. • The trebouxioid lichens may gain an ecological advantage from their capability to counter heavy metal stress with prompt phytochelatin synthesis.

Abstract: Phylogenetic relationships within the family Parmeliaceae (lichenized ascomycetes) with emphasis on the heterogeneous group of cetrarioid lichens are reconstructed. The results are based on cladistic analyses of DNA-sequences, morphological and chemical data. Almost all currently recognized cetrarioid genera were included in the analyses together with parmelioid and alectorioid members of the presumably monophyletic family Parmeliaceae. We tried to sample taxonomic diversity of the family as widely as possible. The ITS1-5.8S-ITS2 region of the rDNA and a partial beta-tubulin gene from 126 samples representing 82 species were analysed. Cetrarioid lichens were identified as a monophyletic group, supported by both ITS and beta-tubulin characters. This group was reanalysed using 47 morphological, anatomical and secondary chemistry characters combined with the DNA data matrix. ITS and beta-tubulin sequences provide congruent information, and a clear correlation between DNA-data and conidial shape is observed. The current taxonomy of the cetrarioid lichens is discussed and compared with the phylogenetic trees obtained here. A comprehensive study of the phylogeography of some bipolar or subcosmopolitic species with representatives from both hemispheres was performed. Cetraria aculeata is the only taxon where correlation between DNA-data and geographic origin is observed.

Abstract: Lichen-forming fungi are mutualistic symbiotic organisms. The mycobiont coexists with one or more algal or cyanobacterial photobionts. Conservation biology of lichens deals, therefore, with more than one organism, although it is the fungal partner, or mycobiont, which is generally the target for conservation. It is also the mycobiont which determines the systematic position of lichens.

Abstract: Green algae are present in desert soils as components of microbiotic communities that also include cyanobacteria and other prokaryotes, lichens, non-lichenized fungi, invertebrates, and other photosynthetic eukaryotes such as diatoms, eustigmatophytes, and xanthophytes. The green algae that occur in crusts are morphologically simple unicells, packets of cells, or weak filaments, yet represent a diverse assemblage of taxa spanning the classes Chlorophyceae, Trebouxiophyceae, and Charophyceae. As part of an ongoing study of the biodiversity of microbiotic crust communities in the western United States and Northern Mexico, a large number of green algae were isolated and characterized morphologically and genetically. Phylogenetic analyses using ribosomal RNA gene sequence data have greatly aided our understanding of the diversity and evolution of desert green algae. Our results indicate that desert green algae evolved from aquatic green algae at least five independent times. In addition, the desert green algae are derived from freshwater, not marine, green ancestors. Some lineages of green algae have a high proportion of desert taxa, while other lineages thus far have no known desert representatives. Many of the isolates are likely to be new taxa. These taxa represent independent lineages of green plants that have evolved to inhabit desert environments. Because they are distinct from but phylogenetically related to embryophyte taxa, these other "land plants" can offer important biochemical and physiological comparisons to desert-dwelling embryophytes.

Abstract: Biological soil crusts arrest soil erosion and supply nitrogen to arid ecosys- tems. To understand their recovery from disturbance, we studied performances of Collema spp. lichens relative to four experimental treatments plus microtopography of soil pedicels, oriented north-northwest to south-southeast in crusts. At sites in Needles (NDLS) and Island in the Sky (ISKY) districts of Canyonlands National Park, lichens were transplanted to NNW, SSE, ENE, WSW, and TOP pedicel faces and exposed to a full-factorial, randomized block experiment with four treatments: nutrient addition (P and K), soil stabilization with polyacrylamide resin (PAM), added cyanobacterial fiber, and biweekly watering. After 14.5 mo (NDLS) and 24 mo (ISKY), both visual rankings of lichen condition and measures of chlorophyll fluorescence were generally higher at ISKY than on more fertile but less stable soils at NDLS. On ENE and NNW pedicel faces, both these values and nitrogenase activity (NDLS only) exceeded corresponding values on WSW and SSE faces. Treatment effects were site specific and largely negative at NDLS; both nutrient and cy- anobacterial addition led to poorer lichen condition, and added nutrients led to reduced fluorescence. Responses to nutrients may have been mediated partly by disturbance of unstable soils and by competition with cyanobacteria. In a separate experiment investigating recruitment responses to adding fungal spores or Nostoc cells, rates of Collema establishment responded significantly to the former but not the latter. Low establishment overall suggests that natural recruitment may occur mainly from iscidia or thallus fragments, not spores. Measured simultaneously on artificial soil pedicels at NDLS and ISKY, both deposition and erosion declined at NDLS across the four pedicel microaspects as: WSW . SSE . NNW . ENE (or ENE . NNW), during fall and spring trials. Patterns were similar at ISKY, but WSW SSE for spring deposition, and deposition did not differ by microaspect in fall. Greater deposition at ISKY, despite higher abundance of cyanobacteria, may be explained by stronger wind velocities. Together, microtopographic differences in erosion, microclimate, and nutrient regimes help explain variable lichen performance, but microtopography influenced lichen perfor- mance more consistently than did any treatment. Demonstrated effects of pedicel devel- opment in crust recovery concur with prior surveys showing greatest microbial biomass and/or cover on ENE and NNW exposures at various spatial scales.

Abstract: s of the XV International Botanical Congress , Yokohama, Japan. Ott, S. (1988) Photosymbiodemes and their development in Peltigera venosa , Lichenologist 20 , 361–368. Ott, S. (1987) Sexual reproduction and developmental adaptations in Xanthoria parietina , Nordic J. Bot. 7 , 219–228. Parks, C.R. and Wendel, J.F. (1990) Molecular divergence between Asian and North American species of Liriodendron ( Magnoliaceae ) with implications for interpretation of fossil floras, Amer. J. Bot. 77 , 1243–1256. Paulsrud, P. (2001) The Nostoc symbiont of lichens. Diversity, specificity and cellular modifications, Acta Universitatis Upsaliensis Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 662 , 1–55. Paulsrud, P. and Lindblad, P. (1998) Sequence variation of the tRNALeu intron as a marker for genetic diversity and specificity of symbiotic cyanobacteria in some lichens, Appl. Environ. Microbiol. 64 , 310–315. Paulsrud, P. Rikkinen, J. and Lindblad, P. (1998) Cyanobiont specificity in some

Abstract: The symbiosis between algae and fungi enables lichens to colonise various apparently hostile places, like high mountains and deserts. However, the sensitive balance between the symbiotic partners can be easily disturbed, as lichens are generally sensitive to environmental alteration such as changes in air humidity (forestry, urbanisation) and air pollution.