Krivoštiansky most
The course of biomonitoring depends on the monitored organisms and the conditions of the location where environmental observation and monitoring take place. The capture of certain animal groups requires specific skills, tools, and, if necessary, protective gear. It is advisable to correlate any monitoring of aquatic organisms with measured water parameters, which provide insights into basic living conditions and may limit the presence of organisms.
Before engaging in field biomonitoring, theoretical preparation is essential. We have developed detailed procedures for fieldwork, as well as study texts to help with the understanding of professional terminology. These procedures and texts are available in the EFFUSE manuals for students and EFFUSE manuals for teachers. Additionally, short video recordings recording from biomonitoring.
Here are some interesting pieces of information about the process of lichen biomonitoring to demonstrate the presence of nitrophilic species, which we conducted at the Krivoštianský bridge site, where lichens are mainly found on the bark of trees. We assessed the degree of pollution using the frequency method, which is explained in the Methods of Biomonitoring.
At the sampling site, the presence of the lichen Xanthoria parietina and Physcia sp. was recorded. In addition to determining the abundance of lichens for biomonitoring, students had the opportunity to familiarize themselves with the reproductive structures (apothecia) of lichens using a magnifying glass and the method of reproduction – the formation of the lichen's stalk. In conditions of sufficient moisture, sunlight (for photosynthesis), wind, and other factors, and in the presence of the alga Trebouxia (photobiont), fungal spores (mycobiont) attach themselves, and the contact with algae triggers the formation of stalks. Clustering of vegetative hyphae creates a more or less continuous layer that can cover the layer of algae (or cyanobacteria), under which these photobionts can also form a continuous layer surrounded by the thallus (tissue) of fungi. Based on this information, students had the opportunity to understand the anatomical structure of lichens. At the same time, students familiarized themselves with the morphology (diversity of shapes) of stalks, as well as basic classification. Based on size, lichens can be divided into two groups – macrolichens (observable with the naked eye) and microlichens (observable with a hand or binocular lens). Macrolichens most commonly have a foliose and fruticose stalk, but also a crustose stalk. Microlichens form a crustose or squamulose, or powdery stalk. The presence of Xanthoria parietina and Physcia sp. on the same substrate is due to the fact that both species contain the same photobiont.
Explanation: The found species are nitrophilic, which explains their presence near the road traffic, as their vitality is positively influenced by the presence of nitrogen compounds. The site was enriched with these species also due to the intense sunlight, which the lichen Xanthoria parietina can absorb thanks to the presence of the pigment parietin.
No lichen species were observed at the site just above the bridge on the left bank of the Laborec.
Explanation: The presence of lichens in a narrow circle was not recorded due to the nature of the environment, which consisted of grassy vegetation and sandy substrate without stones (no epilithic species) within about 5 meters from the watercourse with a low number of trees (no epiphytic species). Also, at a greater distance from the main road (approximately 80 meters), the site is not significantly exposed to sunlight (nitrophilic species), so the occurrence of these species is probably lower (or limited) considering this fact.
Lichens on trees: Xanthoria parietina, Physcia sp. – a low number of stalks compared to the first site; by calculating the formula for determining air pollution, students found a lower level of air pollution.
An interesting observation was the presence of moss species, as it was an environment with a high level of air humidity due to the immediate proximity to the watercourse. Students had the opportunity to observe mosses and, based on a prepared visual aid, compare the anatomical structure of lichens and mosses. They learned to recognize the basic differences between these organisms and were able to determine which organism represents a lichen and which is a representative of mosses. The slope reinforced with stones provided a suitable substrate for epilithic lichen species (such as Rhizocarpon geographicum). On this lichen, the need for these organisms was explained, how they use any substrate for attachment but not for obtaining nutrients from the substrate, as is often mistakenly understood. Students learned that lichens can grow on any substrate – fence, tree, bench, metal, stone, etc., but they do not damage the given substrate in any way.
Explanation: The much lower number of nitrophilic lichen species, especially Xanthoria parietina, confirmed hypotheses about biomonitoring in relation to a greater distance from road traffic.
