Urban green areas contain numerous non-native tree species that may escape from cultivation and potentially become invasive. Climate change is expected to exacerbate this risk by creating favourable conditions for species that are currently climatically restricted. Here, we provide a comprehensive risk screening of 34 non-native urban tree species in continental Europe under current and projected future climate scenarios using the Terrestrial Plant Species Invasiveness Screening Kit (TPS-ISK). Under current conditions, 10 species (29.4%) were categorized as high risk, 23 (67.6%) as medium risk, and one (2.9%) as low risk. Under the projected climate change, 11 species were classified as high risk, including seven categorized as very high risk. Ailanthus altissima, Diospyros virginiana, and Quercus rubra consistently ranked among the highest-risk species, while Acer tataricum subsp. ginnala, Koelreuteria paniculata, Magnolia kobus, Phellodendron amurense, Pseudotsuga menziesii, and Robinia pseudoacacia showed an increased invasion potential under future climate conditions. These findings indicate that climate change may facilitate the establishment and spread of several currently cultivated urban tree species. Our study provides the first comprehensive TPS-ISK screening of non-native urban trees for mainland Europe and identifies priority species for early detection, monitoring, and management.

The organic complexation of Cu2+ in aquatic systems dominates its chemical speciation, affecting its reactivity and bioavailability. Using voltammetry, we investigated Cu2+ organic complexing capacity (CuCC) in atmospheric samples, including water-soluble aerosol fraction, rainwater (wet-only deposition), and bulk deposition (wet and dry deposition), collected in a coastal marine area (National Park Brijuni, Adriatic Sea). The focus was on minimizing analytical interferences from surface-active substances (SAS) that accounted for up to 56% of dissolved organic carbon. Method optimization was performed using model SAS (humic-like substances, fulvic acid, and pollen-derived organic material), resulting in an optimal desorption potential of -1.4 V and the addition of 1 mg/L Triton X-100. Under these conditions, CuCC parameters of average ligand concentration and conditional stability constant of (209.8 +/- 6.7) nM and log K = (10.2 +/- 0.6) in water-soluble aerosol fraction, (117.1 +/- 5.0) nM and log K = (9.6 +/- 0.2) in rainwater, and (142.9 +/- 4.1) nM and log K = (10.2 +/- 0.2) in bulk deposition were determined. Atmospheric inputs represented a source of weak Cu-binding ligands for marine areas. In conclusion, short-term monitoring provided insight into the variability of different atmospheric inputs and offered a methodological basis for future long-term, more comprehensive studies.

Impatiens glandulifera Royle (I. glandulifera) in the EU presents a threat to the ecosystem, and is thus on the list of invasive alien species. The aim of this study was to clarify if an allelopathic effect of I. glandulifera involves the activation of oxidative stress in target plants. First, I. glandulifera leaf extract was prepared and levels of 2-hydroxy-1,4-naphtoquinone (2-HNQ) and 2-methoxy-1,4-naphthoquinone (2-MNQ), as main allelochemicals of I. glandulifera, determined by HPLC. Next, seeds of white mustard (Sinapis alba) or radish (Raphanus sativus) were exposed to the extract or to 2-MNQ (in the concentration range of 1–30 µg/mL) for 3 days and parameters of germination and oxidative stress were assessed. Both the leaf extract and 2-MNQ inhibited germination of white mustard and radish; however, the effect of 2-MNQ was more pronounced. Furthermore, the extract and 2-MNQ induced activation of antioxidative defense and caused oxidative damage to lipids and proteins in white mustard and radish seedlings. It was observed that radish seedlings were less susceptible to negative effect of I. glandulifera extract and 2-MNQ. This study’s obtained results demonstrated that 2-MNQ is the main allelochemical of I. glandulifera and that the mechanism by which I. glandulifera and 2-MNQ induce negative effects to target plants involves oxidative stress. In addition, species-dependent susceptibility to I. glandulifera and 2-MNQ was shown.

Iris taxa are sources of valuable essential oils obtained from aged rhizomes used by various industries, including pharmacy, cosmetic, perfume, and food industry, in which irones are the most important aroma components. In this study, volatile organic compounds (VOCs) obtained from dried rhizomes of three endemics from Croatia, Iris pseudopallida, I. illyrica, and I. adriatica, were studied. The VOCs were isolated by three different methods: headspace solid-phase microextraction (HS–SPME) using divinylbenzene/carboxene/polydimethylsiloxane (DVB/CAR/PDMS) fiber or polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber, and hydrodistillation (HD). The samples were analyzed by gas chromatography–mass spectrometry (GC–MS). In five out of six samples, the main compounds detected by HS–SPME were perilla aldehyde, butan-2,3-diol, acetic acid, 2-phenylethanol, benzyl alcohol, hexanal, and nonanal, while 6-methylhept-5-en-2-one, trans-caryophyllene, and ethanol were common for all studied samples. The former VOCs were absent from the oldest, irone-rich I. pseudopallida sample, mainly characterized by cis-α-irone (43.74–45.76%). When using HD, its content was reduced (24.70%), while docosane prevailed (45.79%). HD yielded predominantly fatty acids, including myristic, common for all studied taxa (4.20–97.01%), and linoleic (40.69%) and palmitic (35.48%) as the major VOCs of I. adriatica EO. The performed GC–MS analyses of EOs, in combination with HS–SPME/GC–MS, proved to be useful for gaining a better insight into Iris VOCs.

It is still unclear how the chemical speciation of Cu in surface seawater is impacted by aerosols from various sources deposited on the sea surface, which is surprising, considering the environmental importance of Cu. Therefore, we used voltammetry to investigate Cu complexing capacity (CuCC) in the sea surface microlayer (SML) and in the underlying water (ULW) of the oligotrophic middle Adriatic Sea during February-July 2019. The focus was on the impacts of specific atmospheric processes such as open-fire biomass burning (BB), pollination season and Saharan dust intrusion. The presence of ligand class L2 (19.9-392.0, average 63.8, median 43.1) nM; log K2 (8.3-10.2, average 9.6, median 9.6) was observed in all samples, while ligand class L1 (40.5-76.1, average 53.6, median 48.9) nM; log K1 (10.3-11.1, average 10.6, median 10.5) was found in only 25% of SML samples. Throughout the period, the SML was enriched with organic ligands by a factor of up to 9.1 compared to the ULW, mainly due to the high sensitivity of the SML to specific atmospheric depositions. In addition, measurements with corresponding specific model aerosols were conducted to analyse their impacts on CuCC. Pollen directly affected CuCC in the SML by increasing the concentration of allochthonous ligands such as proteins. The deposition of BB aerosols rich in nutrients and trace metals stimulated the biological production of organic ligands, showing an indirect effect on CuCC delayed by up to two weeks. Finally, Saharan dust had a negligible impact on CuCC. This study illustrates the susceptibility of oligotrophic coastal area to the effects of pollen and open-fire BB aerosols in altering the Cu-binding organic ligands in the SML.

The palynological study of eight samples from the Gorjani-Topole archaeological site was conducted with the aim of palaeoenvironmental reconstruction. In total, 44 different palynomorphs were recorded: 12 pollen taxa, 23 fungal spores/remains, four algal cysts, one amoebae and four palynomorphs of unknown origin. Among the non-pollen palynomorphs, Chomotriletes (previously Pseudoschizaea) occurred with the greatest frequency and abundance. The low pollen richness accompanied by the presence of only a few sporopolleninrich pollen types indicates unfavourable preservation conditions in the analysed core samples. The dominance of erosion/desiccation indicators supports the scenario of significant oscillations of the hydrological level in the sediments, with periodic drying of the substrate. Although the interpretation of changes in plant cover, due to the reduced pollen spectrum, is not feasible, it is still possible to indicate paleoecological trends and partially interpret them, considering the indicator value of the few preserved palynomorphs. The findings of cultivated grass pollen (Cerealia) and other anthropogenic indicators including weed pollen (Convolvulus arvensis) are of great importance. Moreover, Riccia moss spores or fungal Epicoccum spores could also indicate the anthropogenic impact on the study area.

The study aimed to develop an HPLC method for a simultaneous determination of 2-hydroxy-1,4-naphthoquinone (2-HNQ) and 2methoxy-1,4-naphthoquinone (2-MNQ) in plant material.The method was implemented to determine naphthoquinones (NQs) in leaves and flowers of the invasive alien species Impatiens glandulifera and I. balfourii collected in Croatia.Two NQs extraction methods from plant material were compared: decoction and ultrasonic extraction.Validation parameters indicate that the developed method is reliable for the simultaneous determination of 2-HNQ and 2-MNQ in plant material.The decoction extraction obtained a higher NQs yield than ultrasonic extraction.In the leaves and flowers of I. glandulifera and I. balfourii only 2-MNQ was detected.Both, I. glandulifera and I. balfourii, had higher 2-MNQ concentrations in flowers than in leaves.A significantly higher 2-MNQ concentration was found in I. glandulifera compared to I. balfourii.Therefore, I. glandulifera can be considered a rich source of 2-MNQ whose antitumor potential is established.

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.

Background and Purpose: Pollen grains can come as “ invisible” traces during forensic palynological expertise. As forensic palynology is not carried out in Croatia at all, the main aims of our work were to establish an initial palynological collection for a limited area in Croatia and determine its forensic potential. Materials and Methods: For our case study, we chose a typical town from continental Croatia, Donja Stubica, in which there had been no previous floristic studies. The field survey was conducted during 2005, 2007, and 2021. Floristic and palynological analysis was carried out with an emphasis on the forensic potential of pollen grains. Results: A total of 141 representative plant taxa with pollen samples were collected. The taxonomic analysis showed that the area for the case study was chosen well. Palynological analysis showed that the highest number of taxa had pollen grains that were spheroidal in shape (60%), medium sized (70%), and colporate (41%). The pollen of the majority of taxa had excellent or very important forensic potential, due to their dispersal by insects (60%), a combination of two dispersal methods (23%), and autogamy (1%). In addition, due to the limited distribution of certain rare plants (e.g., Iris sibirica subsp. sibirica in Croatia), their pollen has an even greater forensic potential than the similar pollen of related, more widespread taxa. Conclusion: The generated palynological collection, due to the great forensic potential, could be used in the future as a comparative, and at least partly as a reference forensic collection, applicable in specific cases of legal pollen expertise in Croatia.

Salvia brachyodon, the short-tooth sage, is one of the rarest plant species and endemic in the Adriatic area of the Balkan Peninsula. As aside from its essential oil, only limited information on its phytochemical composition is known, a more detailed study of the leaves was undertaken. From its leaves two diterpenes, agastanol (2), and a new natural compound 1, i.e., 3-methyl-4-methylen-11,12,14-trihydroxy-8,11,13-abietatrien-7-one, were isolated and identified by NMR spectroscopy and mass spectrometry. In addition, caffeic acid, isoquercitrin, luteolin 7-O-glucoside and rosmarinic acid were identfied by comparison with reference compounds. The fraction containg the diterpenes as well as the isolated compound 1 showed significant antimycobacterial activity against Mycobacterium smegmatis. The diterpenes of S. brachyodon represent promising antimycobacterial substances for further evaluation. Due to the endangered nature of the plant, the wide use of S. brachyodon and its bioactive compounds could be achieved by growing the plants in culture.

The aim of this study was to reconstruct the vegetation changes, fire history and local landscape dynamics of central Croatia (the western part of south-eastern Europe) from 9800 cal yr BP to the beginning of the Common Era. Pollen, non-pollen palynomorphs and charcoal were analysed for the first time in the aforementioned area by modern palynological methods. Three different assemblage (sub)zones were identified: “Pinus-Fagus-Quercetum mixtum” (Preboreal), “Fagus-Corylus” (Boreal) and “Alnus-Fagus” (Atlantic, Subboreal and older Subatlantic). Additionally, the oldest observation (~9800 cal yr BP) of beech pollen for continental Croatia was confirmed by radiocarbon dating. Our results indicated a possibly milder climate with less extreme temperatures and higher precipitation during the Preboreal chronozone, alongside intensive flooding, a transition from a mosaic of wetland/wet grassland communities to alder carr during the Boreal, and an unusually long multi-thousand-year period, the annual presence of alder on the mire itself. An increase in the number of secondary anthropogenic indicators can be tracked from the 6th century BC to the beginning of the Common Era. Although regional vegetation changes are insufficiently clear, our results fill a gap in the interpretation of vegetation/palaeoenvironmental changes before the Common Era in in this part of Europe.

The aim of the present paper is to discuss the application of phytolith (microbiomorphic) and non-pollen palynomorph (NPP) analyses to the geoarchaeological study of a Medieval – Early Modern Time period farmyard in Graft, a settlement located in the polder region of North Holland, the Netherlands. The authors have assessed the potential of the methods chosen for studying this type of archaeological site during rescue excavations, when archaeologists often have a limited number of samples or methods for geoarchaeological analysis. The studies conducted have proved the informative value and effectiveness of microbiomorphic and NPP analyses in rescue excavations, especially when applied in combination, thus providing controlling and complementary information for each analysis. The data obtained have provided an important insight into the archaeological interpretation of the cultural layer within the farmyard. In addition, more information was gained on the local palaeoenvironmental dynamics and the phases of economic activity at the farmyard during the 13th–17th centuries CE.

The quality of botanical education depends on the quality and interests of the teacher. The aim of our paper was to conduct an initial study on the attitudes of primary and secondary school teachers about plants and botany. We initiated a study in which 211 biology and 168 teachers of different subjects, from primary to secondary schools in Croatia, participated on a voluntary basis. Statistical analysis was processed using jamovi 2.3 software. Teachers of all profiles (biology and others) had similar attitudes: high opinion about the importance of plants for life and education but not about school botany; botany was in the middle of their scale for potential exclusion from education. The last part of the survey referred only to biology teachers and their interests and suggestions for increasing the attractiveness of botany as a subject. The results showed that botany was the least popular, and within it, teachers were most interested in ecology and horticulture. They suggested that botany would be more interesting with active teaching methods and references to everyday contexts; however, it remains unclear why that is so, as the level of autonomy they are given does enable them to introduce such changes.

In the last decade of the 20th and in the early 21st century a new plant from East Asia, Cardamine occulta, was recorded in many European countries, and evaluated as a potential invasive species. Prior to our research, it had not been observed in Croatia or the neighbouring countries. During 2017, the first plants of C. occulta were discovered in plant nurseries in Zemunik Donji (near the city of Zadar), and in the city of Split. Since then, both sites have been monitored continuously, and the populations in both nurseries are still present and getting denser every year. In this work we aim to present a short history of the discovery, list newly-detected sites and establish some features (taxonomical peculiarities, plant description, distribution, growth and invasive preferences) of the species C. occulta to make its identification easier. Because of its invasive potential and morphological similarity with two other taxa distributed in Croatia, C. hirsuta and C. flexuosa, the determination key for all three taxa, as well as photos of C. occulta have been prepared. This will probably increase the chance of early detection of this species outside of cultivation.

This paper presents the paleoenvironmental reconstruction of a mire sequence near the village Blatuša, with a focus on changes in vegetation composition, hydrological regime and fire history of the Banovina/Kordun area during the last two millennia. For this purpose, pollen, non-pollen and charcoal analysis were done. By the application of CONISS statistical analysis three different pollen assemblage (sub)zones could have been distinguished: a dominance of alder-beech/oaks from the 2nd to the middle of the 7th century, followed by a prevalence of grasses-beech/oaks till the end of the 13th century. Finally, an assemblage of grasses-hornbeam/oaks populated the area from the 14th to the beginning of the 20th century. The high abundance of peat mosses (Sphagnum) from the 11th to the end of the 14th century must indicate increased precipitation and higher frequencies of rainfall during the Medieval Climate Anomaly. Transition from an ombrotrophic to minerotrophic phase of mire evolution during the Little Ice Age is caused by changing in moisture level, with somewhat wetter period prevailing till the middle of the 17th century followed by drier conditions till the beginning of the 20th century. Although cereal pollen grains first appear from the layers dated to the late 14th century and the proportion of secondary anthropogenic indicators were low during the entire Middle Ages, a large number of charcoal particles suggests stronger anthropogenic activity than indicated by observed changes in vegetation composition. Still, a sharp rise of non-arboreal pollen during the Migration period most likely reflect a general natural succession process on mire surface than persuable proof of Avaric-Slavic impact on vegetation. Direct anthropogenic pressure indicated by weeds and cereal pollen can be tracked from the Late Middle Ages onwards.

Himalayan balsam, Impatiens glandulifera Royle, and Balfour’s touch-me-not, Impatiens balfourii Hooker f., are invasive weeds that are threatening habitat diversity in many European countries, including Croatia. Various bioactive secondary metabolites from species of genus Impatiens L. have been reported and some species are traditionally used as herbal medicines. Th e aim of this research was to determine total polyphenol (TP) and total fl avonoid (TF) content, as well as antioxidant activity of leaves and fl owers of species I. glandulifera and I. balfourii. Spectrophotometric methods were used to obtain TP, TF content and inhibition of 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals to measure antioxidant activity. Total polyphenol quantity ranged from 7.9 to 18.6 mg equivalent of gallic acid per g of dried plant material, while total fl avonoid content ranged from 4.6 to 20.5 mg equivalent of quercetin per g of dried plant material. Leaves of I. glandulifera contain more polyphenols than fl owers of the species (18.5 vs. 13.1 mg EGA/g DPM) but less fl avonoids comparing to fl owers (5.7 vs. 8.3 mg EQ/g D PM). However, in the case of I. balfourii both polyphenols and fl avonoids are more abundant in fl owers and have the highest quantity of polyphenols and fl avonoids overall (18.6 mg EGA/g DPM and 20.5 mg EQ/g DPM). Both TP and TF content showed no signifi cant correlation with antioxidant activity, except in the case of TP and DPPH test where correlation was found (r=0.67). Despite diff erences in phenolics, fl owers of I. glandulifera exhibit the highest antioxidant activity in both tests, 3.8 and 3.8 mg EGA/g DPM, for DPPH and ABTS test respectively. In sum, fl owers seem to possess higher quantity of antioxidant compounds than do leaves in case of both species.

This paper presents the paleoenvironmental reconstruction of a mire sequence near the village Blatuga, with a focus on changes in vegetation composition, hydrological regime and fire history of the Banovina/Kordun area during the last two millennia. For this purpose, pollen, non-pollen and charcoal analysis were done. By the application of CONISS statistical analysis three different pollen assemblage (sub)zones could have been distinguished: a dominance of alder-beech/oaks from the 2nd to the middle of the 7th century, followed by a prevalence of grasses-beech/oaks till the end of the 13th century. Finally, an assemblage of grasses-hornbeam/oaks populated the area from the 14th to the beginning of the 20th century. The high abundance of peat mosses (Sphagnum) from the 11th to the end of the 14th century must indicate increased precipitation and higher frequencies of rainfall during the Medieval Climate Anomaly. Transition from an ombrotrophic to minerotrophic phase of mire evolution during the Little ke Age is caused by changing in moisture level, with somewhat wetter period prevailing till the middle of the 17th century followed by drier conditions till the beginning of the 20th century. Although cereal pollen grains first appear from the layers dated to the late 14th century and the proportion of secondary anthropogenic indicators were low during the entire Middle Ages, a large number of charcoal particles suggests stronger anthropogenic activity than indicated by observed changes in vegetation composition. Still, a sharp rise of non-arboreal pollen during the Migration period most likely reflect a general natural succession process on mire surface than persuable proof of Avaric-Slavic impact on vegetation. Direct anthropogenic pressure indicated by weeds and cereal pollen can be tracked from the Late Middle Ages onwards.

Some Iris taxa covered in this study were used or are still being used as remedies in European folk medicine. The most common indication for the decoction of Iris rhizomes is sore throat and productive cough, especially in case of the taxon I. domestica (L.) Goldblatt & Mabb., the wellknown remedy in traditional Chinese medicine. The aim of this study is to chemically characterize rhizomes of seven wild and medicinal Iris taxa and to assess the antioxidant activity of the rhizome extracts. The HPTLC chromatograms and densitometric spectrum scan of the spots were used for untargeted metabolic profiling and tentative metabolite class identification of Iris taxa. Total number of found spots is 41, three major spots are found in all taxa, and 22 spots are found to be taxon specific. Two xanthones, three isoflavonoid glycosides, 18 isoflavonoid aglycons (isoflavonoids), and five acetophenones/benzophenones are tentatively identified. The taxon I. pallida Lam. contains largest amount of phenolic substances (28.5 ± 2.0 mg GAE / g dry plant material) and was the most effective ABTS scavenger (27.5 ± 2.4 mg TROLOXE / g dry plant material). The taxon I. illyrica Tomm. ex Vis. was the most effective in both DPPH and FRAP assays, 10.1 ± 1.5 and 17.3 ± 0.1 mg TROLOXE / g dry plant material, respectively. The most effective taxa in the metal chelating assay were I. croatica Horvat & M.D.Horvat (6.1 ± 0.1 mg EDTAE / g dry plant material) and I. germanica var. florentina (L.) Dykes (5.8 ± 0.1 mg EDTAE / g dry plant material). European Iris taxa have a relatively similar and partly shared chemical profile with Asian taxon I. domestica, which might be a sign of equivalence in the medicinal value.