Training schools play a vital role in COST actions, particularly for young researchers, as they provide opportunities to visit international laboratories and learn new methodologies. In May 2024, CLEANFOREST organized its first training school, Monitoring Spatiotemporal Changes in Global Change Drivers and Their Effects on Semiarid Woodlands and Forests, held at the Faculty of Science of the Universidade de Lisboa. The training school included a field trip designed to explore global change drivers and their impacts on semiarid woodlands and forests. Participants engaged in hands-on activities to understand how forest ecosystems interact with key global change factors such as air quality and climate change. They were introduced to various monitoring techniques and parameters for assessing forest health, including ecosystem fluxes, tree physiology, mortality, and regeneration. Additionally, participants examined plant biodiversity and functional ecology, focusing on lichens and their connection to air quality, and soil physico-chemical properties. Participants applied these methodologies in real-world scenarios, conducting measurements (forest structure assessment, lichen diversity sampling, shrub and herbaceous diversity estimation, deadwood measurement and soil physico-chemical analysis) in different grazing management settings to assess their effects on tree growth, biodiversity, and soil properties. After the practical experience in the field using these experiences, participants were divided into groups to analyze and discuss collected data together with trainers. Key findings were summarized in presentations, together with main take home messages and suggestions on further questions to be explored and related attributes to monitor. This paper presents the field trip protocol used at Companhia das Lezírias, where simplified versions of established methodologies for sampling various ecosystem components were employed. The protocol provides a valuable reference for replicating similar studies, ensuring consistency in methodologies for future training activities.

Societal Impact Statement Ground‐based Inventorying and Monitoring programs are crucial for documenting long‐term forest responses to global change pressures, though there is limited coordination among them. We call for building synergies between different Inventorying and Monitoring programs, as well as community science and stakeholder engagement, to expand the temporal and spatial scale of forest monitoring and better integrate ground‐based monitoring, remote sensing and modelling for timely detection of changes in forest conditions and functioning. This will be beneficial for the Proposal for a Monitoring Framework for Resilient European Forests and other not forestry‐related European Union policies and strategies. Summary There are high expectations from policymakers and society about the role of forests in contributing to climate change mitigation and biodiversity conservation goals, while also supporting a sustainable forest‐based bioeconomy. Yet, multiple global change drivers are undermining forest health and functioning, resulting in great uncertainties around the future of the ecological, economic and social benefits that humanity relies on from forests. Consequently, there is a pressing need to document the state of forests, which is traditionally accomplished through long‐term ground‐based inventorying and monitoring. There are several Inventorying and Monitoring networks in Europe, each with a specific scope, resulting in their independent development and limited interactions. There is now a growing need for a stronger integration across networks, both conceptually and operationally, to achieve an in‐depth assessment of changes in forest status, underlying mechanisms and drivers, to support the development of pan‐European Earth Observation products and the European Union strategies. Here we briefly summarize the forest ground‐based Inventorying and Monitoring networks in Europe, identifying their role, strengths and areas for improvement. We suggest actions that can favour a transition towards a new, co‐operative and effective era in forest monitoring, which can support research, policy and societal needs in a timely manner.

Air pollution and climate change remain critical environmental challenges, particularly in urban areas, where conventional monitoring networks are often too sparse to capture fine-scale exposure gradients due to their high operational costs. Epiphytic lichen biomonitoring provides a valuable complementary approach, as these organisms are sensitive to both air pollutants and climate conditions. Despite the existence of a standardized European protocol, large-scale implementation is hindered by the absence of a robust interpretative framework and incomplete knowledge of species-specific responses to pollutants and climate variables. This study initiated the development of a standardized interpretative framework for European lichen biomonitoring data by identifying a core set of indicator species with clear responses to major air pollutants and climate variables. To achieve this, we compiled and harmonized raw lichen data from 58 studies that applied the European protocol and modeled the response of 43 lichen species to dominant air pollutants (NH3, NOx, and SO2) and climate variables (mean air temperature, mean relative humidity, and temperature seasonality). While confirming established trends, our models allowed us to decouple species responses to reduced (NH3) vs. oxidized (NOx) nitrogen compounds, a distinction rarely achievable in local studies due to insufficient contrast in pollutant gradients. We also provided actionable recommendations to enhance comparability, such as prioritizing widespread, well-studied tree species and standardizing lichen taxa groupings. Our study established a foundation for a harmonized European interpretative framework by identifying low-bias, ecologically meaningful indicator species. Future efforts should focus on translating sensitivity classifications into actionable air quality indices and refining regional-scale assessments.

The addition of biostimulants to nutrient solutions of hydroponically grown crops to speed up plant growth and improve plant yield and quality has been attracting more and more attention. This study investigated the effects of wood distillate (WD) addition to hydroponically grown lettuce (Lactuca sativa L.) plants. Two concentrations of WD, 0.2% and 0.5%, were added to the nutrient solution, and biometric (i.e., leaf fresh weight, root fresh weight, root length and root surface area), photosynthetic (i.e., chlorophyll a, chlorophyll b, and carotenoid content) and biochemical (i.e., electrolyte leakage, total polyphenols, total flavonoids, and total antioxidant power content) parameters were evaluated. The effects of WD were hormetic, as the 0.2% concentration stimulated biometric and biochemical parameters, while the 0.5% concentration inhibited plant growth. Based on these results, it can be suggested that the addition of 0.2% WD to the nutrient solution has a stimulating effect on the growth of lettuce plants, and could be a successful strategy to boost the yield of crops grown hydroponically.

Seed priming with synthetic chemicals may be harmful to the environment and human health. Their replacement with bio-based compounds may overcome these concerns. In this study, we assessed the effectiveness of wood distillate (WD) in enhancing in vitro germination of crop plants using basil, chickpea, and lettuce as case studies. Seeds of the three species were soaked for 24 h in 0.25% and 0.17% WD solutions and then left to germinate for 7 days at 20 °C in a dark germination chamber. Seed pre-treatment with 0.25% WD enhanced germination in all tested species, while 0.17% WD stimulated germination in lettuce and chickpea, but not in basil. For lettuce, 0.17% WD worked better than 0.25% WD. Radicle length of basil and chickpea increased following pre-treatment with 0.25% WD, while in lettuce, it increased after pre-treatment with 0.17% WD. Treating seeds with appropriate WD solutions is a potential strategy to improve germination of crop plants.

The present study evaluated an integrated biomonitoring approach based on three different bioindicators: tree rings, lichens, and beetles in a complex environment (urban-industrial-forest). In Central Italy, four sampling sites were selected to assess the anthropogenic impact of cement plants taking into account (1) long-term exposure (1988–2020) through the analysis of trace elements in tree rings of Quercus pubescens; (2) medium-term exposure (2020–2021) through the analysis of trace elements in thalli (outermost portions) of the lichen Xanthoria parietina; (3) short-term exposure in spring 2021 through the bioaccumulation and evaluation of sample vitality in transplants of the lichen Evernia prunastri and a periodic survey of entomological biodiversity carried out during spring and summer 2021. Trace elements of industrial origin were found in tree rings, with different levels of accumulation between 1988 and 2020 and a maximum in 2012. Native thalli of the lichen X. parietina showed an overall low bioaccumulation of trace elements except for Cr, probably reflecting the influence of national lockdown measures. The transplants of E. prunastri showed a weak stress response in the industrial and urban sites, but not in the forest, and identified Tl and V as the main elements contributing to atmospheric contamination, with peaks at the industrial sites. Concerning the beetles, a significantly lower number of species was found at the Semonte industrial site.

The adoption of innovative cultivation methods, such as hydroponics and aeroponics, is gaining attention due to the unprecedented demand for food that an increasing population is posing on agricultural systems, exacerbating the pressure on already limited arable land. Seeking sustainable and circular economy solutions is imperative, aiming to optimize water consumption and enhance crop yields and quality without resorting to synthetic chemical fertilizers. This study investigated the use of seawater at various concentrations as a base for nutrient solutions, with and without the addition of a natural biostimulant, wood distillate (WD). Four seawater (SW) concentrations (0, 3, 6, and 12%) and two wood distillate concentrations (0 and 0.2%) were applied to assess their impacts on lettuce growth. Findings reveal that seawater at low concentrations (< 6%) serves as an effective water-saving strategy, despite the reduction in the plant ascorbic acid contents. The addition of WD did not inflate growth; in fact, the results obtained are comparable to that of the controls for each concentration of seawater, except at the highest concentration (12% SW), resulting in reduced fresh leaf weights and root areas. Significantly, there was a notable increase in the ascorbic acid contents in all plants grown with WD. Moreover, the WD increased the leaf concentrations in Ca, Mg, P, and K, indicating the higher nutritional value of the crop. This research highlights the potential of combining seawater and WD for sustainable and efficient plant cultivation, suggesting new strategies for exploration across diverse plant species and hydroponic applications.

The Mediterranean biome offers a diverse range of habitats, particularly rocky environments, known for their long-term stability and persistence. Adapted to these rocky surfaces, chasmophytes thrive in this region, benefiting from reduced competition and human interference. The distribution of stress-tolerant cryptogams with generally broad niches represents a significant gap in the biogeography of the region. This study investigates whether complex symbiotic organisms with a potential for long-distance dispersal could serve as biogeographic indicators for delimitation of the Mediterranean biome's boundaries. Through comprehensive chorology data research, saxicolous lichen congeners of the genus Solenopsora were mapped across the Mediterranean Basin as a model area. Environmental predictors (climate and geology) were employed to predict suitable habitats, shedding light on the lichens' ecological niches. Habitat suitability models consistently aligned with the Mediterranean's geographical area, indicating a tight link between lichen distribution and Mediterranean climate classification. While climate change may pose vulnerabilities, no significant range shifts beyond the latitudinal limit of the Mediterranean were predicted. Despite overlapping climatic niches, differences in microhabitat preferences in terms of insolation were observed among studied taxa. Vulnerable regions with potential habitat decreases were identified under future scenarios, emphasizing the importance of environmental heterogeneity in securing local species persistence. This study supports the hypothesis that these lichen symbiotic systems are restricted to the Mediterranean Basin, highlighting their potential to reflect Mediterranean climate, environmental stability, and indicate the boundaries of the Mediterranean biome. Our investigation demonstrates that collection-based research can yield significant contributions to current biogeography.

AbstractiNaturalist is a widely-utilized platform for data collection and sharing among non-professional volunteers and is widely employed in citizen science. This platform's data are also used in scientific studies for a wide range of purposes, including tracking changes in species distribution, monitoring the spread of alien-invasive species, and assessing the impacts of urbanization and land-use change on biodiversity. Lichens, due to their year-round presence on trees, soil and rocks, and their diverse shapes and colours, have captured the attention of iNaturalist users, and lichen records are widely represented on the platform. However, due to the complexity of lichen identification, the use of data collected by untrained, or poorly trained volunteers in scientific investigation poses concerns among lichenologists. To address these concerns, this study assessed the reliability of lichen identification by iNaturalist users by comparing records on the platform with identifications carried out by experts (experienced lichenologists) in three cities where citizen science projects were developed. Results of this study caution against the use of unchecked data obtained from the platform in lichenology, demonstrating substantial inconsistency between results gathered by iNaturalist users and experts.

Forest biodiversity studies conducted across Europe use a multitude of forestry terms,often inconsistently.This hinders the comparability across studies and makes the assessment of the impacts of forest management on biodiversity highly context-dependent.Recent attempts to standardize forestry and stand description terminology mostly used a top-down approach that did not account for the perspectives and approaches of forest biodiversity experts.This work aims to establish common standards for silvicultural and vegetation definitions,creating a shared conceptual framework for a consistent study on the effects of forest management on biodiversity.We have identified both strengths and weaknesses of the silvicultural and vegetation information provided in forest biodiversity studies.While quantitative data on forest biomass and dominant tree species are frequently included,information on silvicultural activities and vegetation composition is often lacking,shallow,or based on broad and heterogeneous classifications.We discuss the existing classifications and their use in European forest biodiversity studies through a novel bottom-up and top-driven review process,and ultimately propose a common framework.This will enhance the comparability of forest biodiversity studies in Europe,and puts the basis for effective implementation and monitoring of sustainable forest management policies.The standards here proposed are potentially adaptable and applicable to other geographical areas and could be extended to other forest interventions.

In the quest for eco-friendly products with biostimulant properties, foliar application of wood distillate (WD) was tested on the growth and yield of chickpea (Citer arietinum L.). WD (pyroligneous acid) is a by-product of plant biomass pyrolysis and is rich in biologically active substances like polyphenols, alcohols, acids and esters. In this work, chickpea plants were sprayed weekly with 100 ml 0.25% (v/v) chestnut (Castanea sativa Mill.) WD during the whole growing period, and at the end physiological and nutritional analyses were performed both on the whole plant and on seeds. While plant height and weight did not change significantly, seeds showed an increase in diameter (+11.2%) and weight (+33.3%), and in the content of starch (+45.9%), total soluble protein (+12.9%), total polyphenol (+16.4%) and antioxidant power (+28.4%). Overall, the content of essential free amino adds increased, except for lysine (-3.4%), phenylala nine (-10.5%) and methionine (-13.7%). Among all the mineral elements analysed, only potassium and magnesium decreased in WD-treated plants, although values were within the common range for chickpea seeds. These results are a clear demonstration of the effectiveness of the use of WD on increasing the nutritional qualities of the edible parts of crop species, thus representing a possible solution to counteract human malnutrition and famine as well as environmental concerns.

The European biodiversity and forest strategies rely on forest sustainable management (SFM) to conserve forest biodiversity. However, current sustainability assessments hardly account for direct biodiversity indicators. We focused on forest multi-taxon biodiversity to: i) gather and map the existing information; ii) identify knowledge and research gaps; iii) discuss its research potential. We established a research network to fit data on species, standing trees, lying deadwood and sampling unit description from 34 local datasets across 3591 sampling units. A total of 8724 species were represented, with the share of common and rare species varying across taxonomic classes: some included many species with several rare ones (e.g., Insecta); others (e.g., Bryopsida) were repre-sented by few common species. Tree-related structural attributes were sampled in a subset of sampling units (2889; 2356; 2309 and 1388 respectively for diameter, height, deadwood and microhabitats). Overall, multi-taxon studies are biased towards mature forests and may underrepresent the species related to other develop-mental phases. European forest compositional categories were all represented, but beech forests were over-represented as compared to thermophilous and boreal forests. Most sampling units (94%) were referred to a habitat type of conservation concern. Existing information may support European conservation and SFM stra-tegies in: (i) methodological harmonization and coordinated monitoring; (ii) definition and testing of SFM in-dicators and thresholds; (iii) data-driven assessment of the effects of environmental and management drivers on multi-taxon forest biological and functional diversity, (iv) multi-scale forest monitoring integrating in-situ and remotely sensed information.

Lichens are one of the most responsive components of the ecosystem to reactive forms of nitrogen. In this work, we selected the lichen genera Cladonia and Usnea, composed of terricolous and epiphytic lichens respectively, and described as sensitive to nitrogen, to test the effects of different doses of nitrogen on lichen physiological parameters (photobiont and mycobiont vitality, chitin quantification, nitrogen content and stable isotopes analysis). The main objectives were to check if the activation of protective mechanisms could be stimulated in case of chronic stress (low nitrogen increase for prolonged time), and, if so, if a toxicity threshold could be identified above which these mechanisms fail. The two lichen genera were generally affected by prolonged exposure to increased nitrogen availability. However, Cladonia rangiformis was able to maintain physiological functioning at the lowest nitrogen doses used, whereas thalli of Usnea become overwhelmed. Moreover, the mycobiont appeared to be more sensitive than the photobiont responding to lower nitrogen doses. Although only studies of longer duration and testing more nitrogen doses will be able to determine an accurate toxicity threshold, these results give important clues on the use of lichens as biomonitors for the establishment of environmental policies.

In the last decades, lichenological studies started again in Lombardia (N Italy), where locally overlooked situations persist.One of such areas is the southernmost part of the Pavese Apennine, where the highest mountains of the Province of Pavia are located.We report the results of a thorough lichen survey carried out in the Natura 2000 Habitat 9130 "Asperulo-Fagetum beech forests" occurring along the Monte Lesima-Cima Colletta ridge, an area with an outstanding naturalistic relevance, part of which is included within the SCI IT2080025 "Le Torraie-Monte Lesima".Ninety-two taxa are recorded from four sites with different features, with the richest site hosting old beech trees and rock outcrops.Circinaria coronata, Glaucomaria subcarpinea, Gyalolechia marmorata, Leproplaca chrysodeta, Pertusaria coronata, Physconia servitii, Variospora paulii and Wadeana dendrographa are new to Lombardia.

EDITORIAL article Front. Environ. Sci., 27 April 2022Sec. Biogeochemical Dynamics https://doi.org/10.3389/fenvs.2022.902547

A common view is that honeybees are mostly managed by beekeepers for commercial purposes or as a hobby, especially in Europe. This misconception is probably due to the lack of systematic studies on wild colonies of honeybees in Europe in comparison to other regions of the world. Since we are used to considering this species as “domesticated”, we may be induced to disregard activities not distinctly linked with colony survival, reproduction, or productivity. Washboarding is one of them in which the entire colony stops resource collection activities; numerous individual bees assemble on the front side of the hive and perform repetitive movements back and forth. They are curiously synchronised but apparently without a scope. In this exploratory work, we carried out a literature review of available, mostly grey, literature. Assuming this behaviour may be linked to cavity-nesting and to tree trunks or rocks being rough surfaces hosting various cryptogams, we performed preliminary observations and manipulative experiments. From our survey, we depict that washboarding is frequently reported in grey literature/beekeepers’ reports, but rarely mentioned in scientific literature. Beekeepers who responded to a designed questionnaire observed this behaviour in various ecological situations, with no trend emerging. Our preliminary experiment of placing cryptogams in front of managed hives resulted in honeybees removing lichens (foliose types) or covering with propolis, and all species were affected. Further research is needed to clarify if lichens are removed because of their chemical compounds, because of hosting potentially toxic microorganisms, or collected as resources.

Lichens have long been considered as composite organisms composed of algae and/or cyanobacteria hosted by a fungus in a mutualistic relationship. Other organisms have been gradually discovered within the lichen thalli, such as multiple algal species, yeasts, or even viruses. Of pivotal relevance is the existence of the lichen microbiome, which is a community of microorganisms that can be found living together on the lichen surface. This community performs a growing number of functions. In this entry, we explore the journey of lichens being considered from a dual partnership to a multi-species symbiotic relationship.

Climate change and atmospheric nitrogen (N) deposition on drylands are greatly threatening these especially vulnerable areas. Soil biocrust-forming lichens in drylands can provide early indicators of these disturbances and play a pivotal role, as they contribute to key ecosystem services. In this study, we explored the effects of different long-term water availability regimes simulating climate changes and their interaction with N addition on the physiological response of the soil lichen Cladonia rangiferina. Three sets of this lichen were subjected to control, reduced watering, and reduced watering and N addition (40 kg NH4NO3 ha−1 year−1) treatments for 16 months. Finally, all samples were subjected to daily hydration cycles with N-enriched water at two levels (40 and 80 kg NH4NO3 ha−1 year−1) for 23 days. We found that reduced watering significantly decreased the vitality of this lichen, whereas N addition unexpectedly helped lichens subjected to reduced watering to cope with stress produced by high temperatures. We also found that long-term exposure to N addition contributed to the acclimation to higher N availability. Overall, our data suggest that the interactions between reduced watering and increased N supply and temperature have an important potential to reduce the physiological performance of this soil lichen.

Forests host most terrestrial biodiversity and their sustainable management is crucial to halt biodiversity loss. Although scientific evidence indicates that sustainable forest management (SFM) should be assessed by monitoring multi-taxon biodiversity, most current SFM criteria and indicators account only for trees or consider indirect biodiversity proxies. Several projects performed multi-taxon sampling to investigate the effects of forest management on biodiversity, but the large variability of their sampling approaches hampers the identification of general trends, and limits broad-scale inference for designing SFM. Here we address the need of common sampling protocols for forest structure and multi-taxon biodiversity to be used at broad spatial scales. We established a network of researchers involved in 41 projects on forest multi-taxon biodiversity across 13 European countries. The network data structure comprised the assessment of at least three taxa, and the measurement of forest stand structure in the same plots or stands. We mapped the sampling approaches to multi-taxon biodiversity, standing trees and deadwood, and used this overview to provide operational answers to two simple, yet crucial, questions: what to sample? How to sample? The most commonly sampled taxonomic groups are vascular plants (83% of datasets), beetles (80%), lichens (66%), birds (66%), fungi (61%), bryophytes (49%). They cover different forest structures and habitats, with a limited focus on soil, litter and forest canopy. Notwithstanding the common goal of assessing forest management effects on biodiversity, sampling approaches differed widely within and among taxonomic groups. Differences derive from sampling units (plots size, use of stand vs. plot scale), and from the focus on different substrates or functional groups of organisms. Sampling methods for standing trees and lying deadwood were relatively homogeneous and focused on volume calculations, but with a great variability in sampling units and diameter thresholds. We developed a handbook of sampling methods (SI 3) aimed at the greatest possible comparability across taxonomic groups and studies as a basis for European-wide biodiversity monitoring programs, robust understanding of biodiversity response to forest structure and management, and the identification of direct indicators of SFM.

Lichens are classified into different functional groups depending on their ecological and physiological response to a given environmental stressor. However, knowledge on lichen response to the synergistic effect of multiple environmental factors is extremely scarce, although vital to get a comprehensive understanding of the effects of global change. We exposed six lichen species belonging to different functional groups to the combined effects of two nitrogen (N) doses and direct sunlight involving both high temperatures and ultraviolet (UV) radiation for 58 days. Irrespective of their functional group, all species showed a homogenous response to N with cumulative, detrimental effects and an inability to recover following sunlight, UV exposure. Moreover, solar radiation made a tolerant species more prone to N pollution’s effects. Our results draw attention to the combined effects of global change and other environmental drivers on canopy defoliation and tree death, with consequences for the protection of ecosystems.