Contrasting Environmental Drivers Determine Biodiversity Patterns in Epiphytic Lichen Communities along a European Gradient

Lichen Biodiversity and Near-Infrared Metabolomic Fingerprint as Diagnostic and Prognostic Complementary Tools for Biomonitoring: A Case Study in the Eastern Iberian Peninsula

In the 1990s, a sampling network for the biomonitoring of forests using epiphytic lichen diversity was established in the eastern Iberian Peninsula. This area registered air pollution impacts by winds from the Andorra thermal power plant, as well as from photo-oxidants and nitrogen depositions from local and long-distance transport. In 1997, an assessment of the state of lichen communities was carried out by calculating the Index of Atmospheric Purity. In addition, visible symptoms of morphological injury were recorded in nine macrolichens pre-selected by the speed of symptom evolution and their wide distribution in the territory. The thermal power plant has been closed and inactive since 2020. During 2022, almost 25 years later, seven stations of this previously established biomonitoring were revaluated. To compare the results obtained in 1997 and 2022, the same methodology was used, and data from air quality stations were included. We tested if, by integrating innovative methodologies (NIRS) into biomonitoring tools, it is possible to render an integrated response. The results displayed a general decrease in biodiversity in several of the sampling plots and a generalised increase in damage symptoms in the target lichen species studied in 1997, which seem to be the consequence of a multifactorial response.

Functional diversity regulates the effects of habitat degradation on biocrust phylogenetic and taxonomic diversities

Biocrusts are major contributors to dryland diversity, functioning, and services. However, little is known about how habitat degradation will impact multiple facets of biocrust diversity and measurable functional traits. We evaluated changes in taxonomic, functional, and phylogenetic diversity of biocrust-forming lichens along a habitat degradation gradient related to the presence of linear infrastructure (i.e., a road) and a profound agricultural driven transformation. To do so, we selected 50 remnants of a Mediterranean shrubland. We considered several surrogates of habitat quality and causal disturbance on the various diversity facets of biocrusts by using structural equation modeling, hypothesizing that habitat degradation primarily affects functional diversity, which in turn regulates changes in taxonomic and phylogenetic diversities, and also that taxonomic and phylogenetic diversities are coupled. Fragment connectivity, distance to linear infrastructure (i.e., a road) and, particularly, soil fertility (i.e., soil P concentration), had mostly negative effects on biocrust functional diversity, which in turn affected both taxonomic and phylogenetic diversities. However, we found no direct effects of habitat degradation variables on the taxonomic and phylogenetic diversities. We also found that increases in phylogenetic diversity had a positive effect on taxonomic diversity along the habitat degradation gradient. Our results indicate that functional diversity of biocrusts is strongly affected by habitat degradation, which may profoundly alter their contribution to ecosystem functioning and services. Furthermore, functional diversity regulates the response of biocrust taxonomic and phylogenetic diversity to habitat degradation. These findings indicate that habitat degradation alters and simplifies the diversity of functional traits of biocrust-forming lichens, leading to biodiversity loss, with important consequences for the conservation of global drylands biodiversity.

Distribution Types of Lichens in Hungary That Indicate Changing Environmental Conditions

Simple Summary

As the occurrences of lichens are strongly correlated to background environmental conditions (e.g., air pollution, global warming), the analysis of their distribution has a great value for bioindication. Distribution data are originating from earlier herbarium collections, recent field and literature studies. The distribution analyses in lichen species with different ecological requirements allowed comparisons and showed clear trends. Five distribution types were introduced—presented by characteristic examples—according to lichen distribution maps prepared in different periods of time (representing changing environmental conditions): (1) species of decreasing occurrences by time (acidic pollution sensitive species), (2) species with no or few former records but with increasing occurrences in recent decades (sub-Mediterranean species), (3) species with increasing and then (from c. 2000) decreasing occurrences (acidofrequent species), (4) species with widely increasing occurrences in recent decades (nitrofrequent species), and (5) species with rapidly increasing occurrences (rapidly spreading species of uncertain reasons). The discussed trends are known for some species at a global scale or European level, other examples are characteristic for Central Europe or Hungary. By studying the distribution maps of lichen bioindicators, tendencies of climate change and type of pollution can be determined and further changes can be predicted.

Abstract

Distribution data originating from earlier herbarium collections and recent biodiversity records form the basis of distribution analyses in lichen species with different ecological requirements, where the records allowed comparisons or showed clear trends. As the occurrences of lichens are strongly correlated to background environmental conditions (e.g., air pollution, global warming), confirmed by Wirth’s ecological indicator values, the analysis of distribution types has a great value for bioindication and the establishment of current and future climatic and pollution situations. Five distribution types were introduced—presented by characteristic examples (13)—according to lichen distribution maps prepared in different periods of time (representing changing environmental conditions): (1) species of decreasing occurrences by time (e.g., Lobaria pulmonaria, Menegazzia terebrata, suboceanic, acidic pollution sensitive species), (2) species with no or few former records but with increasing occurrences in recent decades (e.g., Flavoparmelia soredians, Hyperphyscia adglutinata, Solenopsora candicans, sub-Mediterranean species), (3) species with increasing and then (from c. 2000) decreasing occurrences (e.g., Scoliciosporum chlorococcum, Straminella conizaeoides, acidofrequent species), (4) species with widely increasing occurrences in recent decades (e.g., Physcia aipolioides, Piccolia ochrophora, Xanthoria parietina, nitrofrequent species), and (5) species with rapidly increasing occurrences (e.g., Absconditella lignicola, Coenogonium pineti, Evernia divaricata, rapidly spreading species). The proposed distribution types of lichen species may be applied to wider regions (the European or the global level).