A new species and new records of Leptogium (Ach.) Gray (Collemataceae, Peltigerales) from Rio Grande do Sul State with an identification key for the genus.

Specimens of Leptogium collected in ten localities from the State of Rio Grande do Sul were studied. Sixteen species were found of 28 records mentioned to the state, which represents around 57% of the Leptogium diversity known for Rio Grande do Sul. Leptogium exaratum is proposed as a new species. Leptogium atlanticum, L. milligranum and L. vesiculosum are reported for the first time to the state. The lectotype of L. javanicum is reported here and detailed descriptions are provided to the examined specimens. An identification key is showed with all the 28 mentioned species of Leptogium. It is the first published taxonomic key for Leptogium from Rio Grande do Sul, the State with the highest diversity of this genus in Brazil.

Air quality assessment in different urban areas from Rio Grande do Sul state, Brazil, using lichen transplants.

Based on the need to monitor air pollution and on the importance of doing it with biological organisms, the present work had as main objective to assess air quality in urban areas through lichen transplants. Besides, we also tested whether there were differences among the studied sites, aiming to point out the main pollution characteristics of the areas. The monitoring was carried out in seven cities, which varied from mainly rural to mainly industrial, in Rio Grande do Sul, southern Brazil. The foliose lichen Parmotrema tinctorum was used as the biomonitor species. Physiological tests and contents of sulphur and heavy metals were measured in the lichen thalli. Other pollutants assessed through air samplers were available for some cities, and modeled concentrations of fine particulate matter and nitrogen oxides for all sites. The effect of air pollution negatively reflected on the physiology parameters of the lichen and the concentration of all heavy metals increased after exposure, especially in the industrial sites. We generated a profile of air pollutants and pointed out that Charqueadas and Esteio had the worst air quality. Since they have high demographic densities, the results are of great public health concern and could be guidelines for future studies.

Selecting lichen functional traits as ecological indicators of the effects of urban environment.

Air pollution and the urban heat island effect are known to directly affect ecosystems in urban areas. Lichens, which are widely known as good ecological indicators of air quality and of climatic conditions, can be a valuable tool to monitor environmental changes in urban environments. The objective of this work was to select lichen functional traits and functional groups that can be used as ecological indicators of the effects of urbanization, with emphasis in the Southern subtropics, where this had never been done. For that, we assessed lichen functional composition in urban sites with different population density, which was considered as proxy for grouping sites in two levels of urbanization (low and medium/high). This a priori grouping was based on their significantly differences on air pollutants and land cover. Urbanization and air pollution showed to affect all lichen functional traits, with different responses depending on the functional group. Medium/high density urbanization was associated to an increase on the mean relative abundance of lichens with chlorococcoid green algae, foliose narrow lobes, soredia as the main reproduction strategy, pruinose thallus and containing secondary metabolites for chemical protection. Lower density urbanization showed a higher relative frequency of cyanolichens and lichens with Trentepohlia as the main algae, loosely attached crustose thallus and isidia as the main reproductive structure. The differences found on photobiont and growth form traits in response to the environmental variables used as proxies of microclimatic conditions (forest cover and number of trees around the sampling units), enabled us to detect the urban heat island effect (drier conditions in more urbanized sites).

The application of lichens as ecological surrogates of air pollution in the subtropics: a case study in South Brazil.

The use of lichens as ecological surrogates has been an important tool to evaluate the impact of air pollution in both ecosystem and human health but remains underused in the subtropics due to lack of knowledge. Aiming to support the application of lichen as ecological surrogates of the effects of air pollution in the subtropics, we hypothesized that urbanization was an important driver of changes on lichen diversity, composition, and vitality. For that, we quantified several lichen diversity metrics (richness, cover, and community composition) and photobiont vitality in relation to atmospheric pollution or its surrogates (modeled pollutant gases, pollutants in lichen thallus, and land cover). We confirmed that air pollution was a key driver for lichen diversity. Changes in lichen community composition and vitality were very significantly related to air pollution and integrated the effect of multiple stressors (particulate matter, NOx, and Cu), thus being powerful ecological indicators of air pollution in the subtropics.