Invasive Alien Plants occur in numbers differing by orders of magnitude at subsequent invasion stages. Effective sampling and quantifying niches of rare invasive plants are quite problematic. The aim of this paper is an estimation of the influence of invasive plants frequency on the explanation of their local abundance. We attempted to achieve it through: (1) assessment of occurrence of self-regenerating invasive plants in urban woodlands, (2) comparison of Random Forest modelling results for frequent and rare species. We hypothesized that the abundance of frequent species would be explained better than that of rare ones and that both rare and frequent species share a common hierarchy of the most important determinants. We found 15 taxa in almost two thirds of 1040 plots with a total number of 1068 occurrences. There were recorded 6 taxa of high frequency–Prunus serotina, Quercus rubra, Acer negundo, Robinia pseudoacacia, Impatiens parviflora and Solidago spp.–and 9 taxa of low frequency: Acer saccharinum, Amelanchier spicata, Cornus spp., Fraxinus spp., Parthenocissus spp., Syringa vulgaris, Echinocystis lobata, Helianthus tuberosus, Reynoutria spp. Random Forest’s models’ quality grows with the number of occurrences of frequent taxa but not of the rare ones. Both frequent and rare taxa share a similar hierarchy of predictors’ importance: Land use > Tree stand > Seed source and, for frequent taxa, Forest properties as well. We conclude that there is an ‘explanation jump’ at higher species frequencies, but rare species are surprisingly similar to frequent ones in their determinant’s hierarchy, with differences conforming with their respective stages of invasion.

Plants along mountain slopes experience strong environmental variation, particularly declining air temperature with increasing elevation. Investigating intraspecific variation in morphological traits and biomass allocation across elevational gradients can reveal how plants adjust their life-history strategies to climatic conditions, improving our understanding of their resilience to climate change. We analysed variation in overall morphology and biomass allocation in two high-elevation species: Campanula alpina and Doronicum stiriacum, both centred in the alpine belt. Their elevational responses were compared with three species exhibiting wider elevational occurrence: Soldanella carpatica (lower montane to subnival belt), Bellidiastrum michelii (lower montane to alpine belt), and Senecio subalpinus (lower montane to subalpine belt). All five species showed decreasing plant height with increasing elevation. However, high-elevation species maintained stable aboveground biomass and reproductive allocation, while species with wider elevational occurrence exhibited more than 50% reduction in aboveground biomass, and two of them showed significant decline in flower biomass with elevation. Our findings confirm that species with wider or lower elevational ranges exhibit greater trait variation than high-elevation specialists. These patterns suggest that mountain generalist species, with lower elevational preferences and wider elevational occurrence, may respond more strongly to rising temperatures, potentially increasing aboveground biomass and plant height under future climate change. In contrast, high-elevation species demonstrated the ability to persist across a wide temperature range while maintaining stable biomass, indicating physiological tolerance and potential to withstand warming in alpine environments. Further research is needed to understand how high-elevation specialists maintain stable growth and reproductive output, particularly their eco-physiological adaptations.

Understanding the relationship between disturbance and forest community dynamics is a key factor in sustainable forest management and conservation planning. The study aimed to determine the main factors driving unusual differentiation of forest vegetation into four communities, all coexisting on the same geological substrate. The fieldwork, conducted on the fluvioglacial sand area in Central Poland, consisted of vegetation sampling, together with soil identification and sampling, up to depths of 150 cm. Additional soil parameters were measured in the laboratory. A Geographical Information System was applied to assess variables related to topography and forest continuity. Vegetation was classified and forest communities identified. Canonical Correspondence Analysis indicated significant effects of organic horizon thickness, forest continuity, soil disturbance and soil organic matter content on vegetation composition. We found that the coexistence of four forest communities, including two Natura 2000 habitats, a Cladonia-Scots pine forest and an acidophilous oak forest (codes–91T0 and 9190 respectively), resulted from former agricultural use of the land followed by secondary succession. The lowest soil-disturbance level was observed within late-successional acidophilous oak forest patches. Nearly complete soil erosion was found within the early-successional Cladonia-Scots pine forest. We propose that both protected habitat types may belong to the same successional sere, and discuss the possibility of replacement of the early- and late-successional forest habitat types in the context of sustainable forest management and conservation.

North American goldenrods ( Solidago spp.) rank among the most ecologically impactful invasive plants in Europe, Asia, and other regions. Their spread is driven by high ecological plasticity, rapid growth, and allelopathic effects. While the number of publications on Solidago invasions has grown substantially in recent decades, existing reviews tend to be narrative and focus on single species or few mechanisms. In this systematic review, we analyze 180 peer-reviewed empirical studies to assess global trends, methodological approaches, and research biases in studies addressing interactions between invasive Solidago and the environment. Most studies applied a single methodological approach, with ex situ experiments dominating, while field observations and in situ manipulative experiments were less common. Long-term studies were rare, and research primarily addressed current conditions rather than future scenarios. The taxonomic focus was centered on S. canadensis L., with other species being much less studied. Geographically, research was concentrated in Europe and Asia, with field-based studies more common in Europe and ex situ experiments dominating in Asia. Solidago spp. served as either a response or an explanatory variable, reflecting both its response to environmental conditions and its impact on the invaded ecosystem.

This paper offers a critical analysis of the flora of the Bielański Forest in Warsaw (central Poland), originally documented by Erndtel in 1730. It examines the historical and natural conditions that established the Bielański Forest as one of the earliest botanical research sites in the region and in the country. The analysis identified 36 plant species reported from this location, with 35 species given modern classifications. The findings included one moss, one fern and 33 flowering species. Of these, 15 are common species currently found in the Bielański Forest. An additional seven species were reported in the 19th and early 20th centuries, though they are now only known from other areas in Warsaw and its surroundings. The remaining 13 species have not been observed in the Bielański Forest since Erndtel’s time. The study also discusses fungi and lichens documented in the 17th and 18th centuries from Warsaw and its vicinity. Notable plant species identified by Erndtel include Aruncus sylvestris Kostel., Bupleurum longifolium L., Phyteuma orbiculare L. and Silaum silaus (L.) Schintz & Thell., which are uniquely located in Bielany and have not been reported elsewhere in Mazovia. Among others, reported in the 19th century in the area, was Cypripedium calceolus L., which is very rare in central Poland. The Bielański Forest, one of the most extensively studied natural sites in Mazovia, may serve as a model for understanding the historical transformations of flora. The initial review of Erndtel’s list by Hryniewiecki in 1954 now requires verification and correction, and a comprehensive evaluation of Erndtel’s work is expected to provide further valuable insights into the history of the region’s flora.