Given the rapid spread of invasive alien plant species in Europe and limited information regarding their distribution and dispersion patterns, we analyzed the invasive risk of Humulus scandens, a species with an increased invasive potential. We collected occurrence records from Romania within an EU funded project and literature data, in order to perform an ensemble distribution model. Environmental variables varied from downscaled topoclimatic continuous entries to categorical ones, such as soil class, texture, or land use. Results showed potential core areas of the species within the study region. By inverting the probability output of the models, we have created a resistance surface which helped us model its dispersion patterns. Further, we assessed the probability of invasion for each resulted corridor using the species dispersion ecology and created an invasion risk map. H. scandens is highly influenced by milder climates and areas with constant flooding events, thus we found that the Tisa basin and its tributaries can be under a high invasion risk, spreading through the entire catchment, in Central, Western, and Northern Romania, towards the Eastern Carpathians. The Danube acted as a dispersion corridor for major river systems in southern Romania, but the dispersion capability of the species dropped in steppe areas with higher aridity and limited water course network. This approach is useful for creating adequate action plans in relation to invasive alien plant species, and should urgently be regarded, as results show a potentially large distribution of H. scandens across entire water catchment areas, with devastating effects on natural ecosystems.

Biological invasions pose an increasing risk to nature, social security and the economy, being ranked amongst the top five threats to biodiversity. Managing alien and invasive species is a priority for the European Union, as outlined in the EU Biodiversity Strategy for 2030 and the Kunming-Montreal Global Biodiversity Framework. Alien plant species are acknowledged to impact the economy and biodiversity; thus, analysing the distribution of such species provides valuable inputs for the management and decision-making processes. The database presented in the current study is the first consolidated checklist of alien plant species that are present in Romania, both of European Union concern and of national interest. This database complements a prior published distribution, based only on records from literature, bringing new information regarding the occurrence of alien plants in Romania, as revealed by a nationwide field survey. We consider this database a valuable instrument for managing biological invasions at both national and regional levels, as it can be utilised in further research studies and in drafting management and action plans, assisting stakeholders in making informed decisions and implementing management actions. We present the results of the first nationwide survey of alien plant species in Romania, conducted between 2019 and 2022, in the framework of a national project coordinated by the Ministry of Environment, Waters and Forests and the University of Bucharest. The present database complements and updates the database published by Sirbu et. al (2022), which included occurrence records published until 2019. The new database includes 98323 occurrence records for 396 alien plant species in 77 families, with most species belonging to the Asteraceae family. One alien plant species in our database, the black locust Robinia pseudoacacia L., had more than 10,000 occurrence records. The distribution database also includes information on newly-reported invasive alien plant species of European Union concern in Romania (i.e. the floating primrose-willow Ludwigia peploides (Kunth) P.H.Raven) and documents the presence of plants in 44 additional families compared to Sirbu et al. (2022). Each entry includes information on species taxonomy, location, year, person who recorded and identified the alien plant, geographical coordinates and taxon rank.

Bat species inhabit subterranean environments (e.g., caves and mines) in small areas with specific microclimatic conditions, during various periods of their life cycle. Bats can be negatively influenced by microclimatic changes within their roosts if optimal habitat patches become unavailable. Therefore, proper management solutions must be applied for the conservation of vulnerable bat populations, especially in show caves. We have pursued an ensemble species distribution modelling approach in subterranean environments to identify sensible patches for bats. Using multi-annual temperature monitoring and bat distribution surveys performed within ten caves and mines, including show caves, we modelled relevant habitat patches for five bat species. The temperature-based variables generated from this approach proved to be effective when processed via species distribution models, which generated optimal validation results, even for bats that were heavily clustered in colonies. Management measures are proposed for each show cave to help in long-time conservation of hibernation and maternity colonies. These measures include creating suitable microclimatic patches within the caves by ecological reconstruction measures, tourist management practices in relation to bats, and show cave fitting recommendations. This approach has never been performed at this scale due to the complex geostatistical challenges involving subterranean environment mapping and can be further used as best practice guidelines for future conservation projects.

Background and aims – Ligularia sibirica is a glacial relict plant species in Europe. Its populations are rare and endangered in most of the European localities. Studies on glacial relics are insufficient; among them only a few focus on the population characteristics and their reproductive capacity. We aimed to determine the habitat requirements of L. sibirica populations; which factors affect the reproductive output of the populations and how the interaction of ecological and biological parameters influences their germination capacity.Methods – We described habitat conditions in terms of the Ellenberg indicators (for nitrogen availability, moisture, light, soil reaction, and temperature) in each analysed population. To determine which factors affect the population viability we performed a series of regression analyses. Germination experiment was carried under laboratory-controlled conditions at a 14/10 h. photoperiod and 24/16°C temperature, for 32 days, with cold stored seeds (at 4°C), and seeds stored at room temperature on a different substrate (moist filter paper and oligotrophic soil). The parameters influencing population germination rate were determined with general linear models.Key results – We found that the soil humidity, nitrogen availability, temperature, and lighting are the ecological factors influencing the morphological features of L. sibirica populations. The largest seeds are in the middle part of the inflorescence though this parameter has no influence on germination rate. The seeds germinated better on moist filter paper. Cold stored seeds did not show higher germination rate. Germination increased with the altitude of the populations and the seeds mass, whilst higher values of density had a negative influence on it.Conclusions – Our results suggest that habitat conditions and population characteristics are highly related to the germination success of L. sibirica. The prosperity of a population (expressed by the number of individuals) is not a guarantee of reproductive success, the densest populations having the lowest rates of germination.

Alina Georgiana CÎȘLARIU, Pavel ICHIM & Ciprian Claudiu MÂNZU - LONG TERM CHANGES OF WETLANDS IN THE CONTEXT OF ANTHROPIC INFLUENCES: THE CASE OF ROSCI0222 (NORTH-EASTERN ROMANIA), Carpathian Journal of Earth and Environmental Sciences, February 2020, Vol. 15, No. 1, p. 27 - 36; DOI:10.26471/cjees/2020/015/105

Modern pollen rain studies provide essential calibration for interpreting fossil pollen records, particularly in montane environments. This study explores pollen–vegetation relationships along an altitudinal transect in the Rarău Massif (Eastern Carpathians, Romania). Eight moss cushion samples collected between 1215 and 1619 m a.s.l. were analysed palynologically and compared with eight paired vegetation surveys. Multivariate analyses, including hierarchical clustering, Mantel tests, NMDS, and Procrustes analysis, were applied to evaluate floristic and palynological similarity in relation to altitude. Pollen spectra are dominated by Picea, reflecting the prevalence of spruce forests characteristic of the montane belt, while Abies and Pinus occur in lower proportions, indicating a secondary role. Broad-leaved taxa such as Fagus, Betula, and Alnus complement the arboreal pollen signal, whereas thermophilous taxa Quercus and Tilia represent extra-local pollen input from lower altitudes. Herbaceous and shrub taxa are generally underrepresented in the pollen record relative to field observations. Pollen taxa associated with anthropogenic disturbance (Plantago, Rumex, Artemisia and Urtica) show a constant presence, which may suggest localized human influence likely linked to grazing and tourism. Statistical results show weak and non-significant correlations between pollen composition, vegetation structure, and altitude. Overall, modern pollen rain reflects the dominant vegetation structure of the studied montane belt but shows limited fidelity at the local floristic scale.