AbstractBreeding ecology remains poorly understood in many elusive species because conventional field methods rarely produce samples large enough to detect broad-scale ecological patterns. Here, we show that open-source online photographs can help overcome this limitation. Using 657 photographs representing 500 nests, we quantified breeding habitat and nest-site characteristics of the Eurasian woodcock (Scolopax rusticola) across its Palaearctic breeding range. We scored forest type, surrounding vegetation, nest concealment, proximity to trees and plant-based Ecological Indicator Values for Europe (EIVE). Woodcocks showed clear preferences for broadleaved stands, especially those associated with birch (Betula spp.) and oak (Quercus spp.), while coniferous trees were used less than expected from regional availability. Nest sites were typically located in mesic, slightly acidic, semi-open woodland habitats. At finer spatial scales, nest placement was highly variable, ranging from open ground to dense cover although many nests were placed close to trees or dead wood. Nesting habitat also changed seasonally, with later nests more often concealed by vegetation and more frequently located in mixed or coniferous stands. Our results demonstrate that openly available images can reveal otherwise inaccessible patterns in breeding ecology and provide a scalable tool for studying secretive species across large geographic ranges.

Understanding what determines species' ecological success is a central challenge in ecology. Competitive ability and abiotic tolerance are expected to be strong predictors of species success, yet theory predicts a trade-off between them. Since some traits are phylogenetically conserved whereas others are evolutionarily labile, species may have the potential to combine competitive ability with abiotic tolerance. We conducted a garden experiment involving 23 wetland species under two contrasting hydrological regimes and quantified performance measures to assess species responses to competition and abiotic conditions. We also measured structural, physiological, and morphological traits, and related both to species success, quantified as realized niche breadth and local dominance across 19 000 vegetation plots. Niche breadth and local dominance were most strongly associated with competitive effect, and to a lesser extent with abiotic tolerance. The most successful species expressed traits associated with a phylogenetically conservative persistence-stature functional dimension (high LDMC, tall stature, and deep roots) together with traits of evolutionarily labile acquisitive physiology (low δ13C, high stomatal conductance, and elevated leaf nitrogen), indicating high gas exchange and sustained carbon acquisition while trading off rapid growth. Our findings show that competitive strength and abiotic tolerance can co-occur, helping explain why certain evolutionary lineages dominate wetlands.

Although many floodplain forests in Central Europe are protected as nature reserves, there is ongoing significant biodiversity loss. The current practice of leaving these forest ecosystems to natural processes seems inadequate and should be adapted to include active management. The age-class diversity, much like the structural diversity created by traditional forest practices, can be essential for maintaining biodiversity by providing a variety of microhabitats. We assessed the effects of different age-class structures between two time periods, i.e. 60 years ago and present on forest understorey vegetation across four floodplain areas of large rivers in Central Europe. We resampled 117 vegetation plots to find significant differences in species richness and composition between age classes and calculated so-called age-class evenness to compare overall distribution of age classes between historical and current plots. The age class structures of 60 years ago were associated with much higher species richness than the age class structures of today. Specifically, the oldest forests in the 1960s aged 60-80 years had unique vegetation composition supported all forest species groups. We concluded that a patchwork of diverse age classes including old-growth stands promotes the highest possible species richness in floodplain forests as each of those age classes provide different light conditions and thus light-demanding as well as shade-tolerant species can coexist. In addition, the younger forest stands should be used as coppices or coppices-with-standards. On nutrient-rich soils with high clay content, the coppicing should be accompanied by traditional management practices that regularly remove a significant proportion of the biomass.

The dynamics of reproductive allocation (RA) in herbaceous plant communities, particularly in response to varying environmental conditions such as drought stress and competitive interactions, remain underexplored. This study aims to fill this gap by hypothesising that both belowground resource limitation and the presence of dominant species significantly influence RA strategies within plant communities, leading to different patterns of reproductive synchrony. We also expected different effects of resource limitations on interspecific synchrony in RA compared to intraspecific synchrony. We conducted a mesocosm experiment in an experimental garden over five years, exposing wetland plant communities (one dominant species and three subordinate species) to different drought stress regimes and a dominant removal treatment. The dominant species achieved high RA at wet sites, where conditions were most favourable for generative reproduction. Community‐level synchrony increased under drought, reflecting both resource limitation and the competitive influence of the dominant species, which caused subordinate species to converge in their reproductive strategies. Detrended analyses confirmed that these shifts were not driven solely by temporal trends but represented year‐to‐year co‐fluctuations. Intraspecific synchrony remained high in most species, with some subordinate species further increasing synchrony under drought, whereas the dominant species tended to lose synchrony. Overall, our findings demonstrate that reproductive synchrony at the community level is not only a consequence of intrinsic species strategies but also emerges from hierarchical interactions, with dominant species shaping reproductive dynamics under environmental stress.

In recent decades, temperate forests have been significantly disturbed by introduced pests and pathogens, which are likely to trigger cascading environmental changes. This study investigated the interactive effects of the pathogen Phytophthora alni and different environmental variables on understorey vegetation changes in wetland forests. We expected differential effects of P. alni based on moisture regimes and spatial isolation of forest sites, taking into account changes in climate, soil and canopy structure. After almost two decades, we re-surveyed vegetation on 214 forest sites and monitored P. alni that has spread rapidly and is now present in almost half of the sites. We observed a general decline in herb diversity, particularly in streamside forests, where it decreased by 23 %. These changes were largely explained by other environmental factors and to a lesser extent by the invasion of Phytophthora alni. The greatest decline in understorey diversity was observed in streamside forests, likely due to successional changes and their location as fragments in an agricultural landscape more vulnerable to drought. In contrast, the decline in species richness was less pronounced in alder carrs and spring forests, possibly because these habitats are located within larger forested areas and are less exposed to drought. The effect of the pathogen was strongest in alder carrs, suggesting that waterlogged sites with stagnant water are more vulnerable to the spread of P. alni.

Aim Understanding temporal patterns of vegetation change is crucial for assessing the ecological integrity of forest understoreys under shifting management and climate regimes. This study investigates long-term (60-year) and short-term (10-year) changes in species composition, functional traits, and phylogenetic diversity (PD) of understorey communities in Central European floodplain forests. The goal is to determine how different temporal scales capture ecological dynamics and to identify trait-based mechanisms underlying community shifts.Location The research was conducted in floodplain forests across Central Europe, encompassing oak, ash, hornbeam, and willow-dominated stands distributed along a gradient of soil moisture availability.Methods We analyzed repeated vegetation plot records across two temporal scales. Changes in species richness, functional diversity (FD), and PD were quantified. Species-level shifts were linked to plant traits such as height, seed mass, and leaf dry matter content (LDMC), with analyses stratified by forest type.Results Over 60 years, species richness and PD declined, driven by the loss of phylogenetically distinct light-demanding specialists and an increase in tall woody generalists with conservative strategies. FD remained stable but showed directional trait shifts. In contrast, the 10-year data showed limited changes in diversity indices, despite continued increases in some woody species and temporary gains of specialists in drier hornbeam stands. Trait-abundance correlations indicated that taller species with high LDMC or heavier seeds were favored under conditions of canopy closure and drought. Invasive species also increased in abundance over the 60-year period, whereas short-term trends exhibited weaker signals.Conclusions Long-term data revealed compositional and trait-based transformations missed in short-term assessments, emphasizing the value of extended temporal monitoring. Trait-environment interactions varied among forest types, reflecting site-specific drivers such as differences in moisture conditions. These findings highlight the need for temporally informed forest management strategies that promote resilience by addressing both species impoverishment in the forest understorey and trait-based filters.

Aim: The potential analogues in Earth's past may hold insight on how modern European forests will react to different levels of future warming. There is a lack of comparison between future warming and its most recent climate analogue 3.25 million years ago during the mid-Piacenzian warm period. We have attempted to fill this knowledge gap by modelling the zonation of woody plant communities during the mid-Pliocene and comparing it with their current distribution and predictions of their future distribution. Location: Europe. Time Period3.25-3 million years ago, 1970-2000, and 2081-2100. Taxon: European tree species. Methods: In this study, we selected 15 European tree species from three main European forest ecosystems: Mediterranean, temperate and boreal species that had ancestors present in Europe during the mPWP. Then we applied an ensemble model using climatic data from the mPWP, modern and two future climate scenarios. In order to compare the models, we assessed the overlapped area as well as Dutilleul's modified t-test in order to assess the spatial similarities in forest communities distribution between the mPWP and future warming. Results: Our results showed that there is a clear northern trend in the northward shift of forest communities under all warming scenarios. Across all species, there is a clear drop in suitable area with the exception of Mediterranean species, where suitable area increased in all warm scenarios. When comparing the mPWP with future warming, there is evidence to support that RCP 4.5 will potentially exhibit similar conditions, while RCP 8.5 may result in highly novel habitats. Main Conclusions: Although mid-Pliocene conditions are more analogous to the RCP 4.5, it raises an urgent ecological concern for adaptive forest management. Increasing temperatures and uncertain precipitation patterns have the potential to aid the expansion of Mediterranean forest communities while fragmenting temperate and boreal forest communities throughout central Europe.

Restoration efforts increasingly focus on light-enhancing treatments to create open forests with high biodiversity. However, climate change and forest eutrophication, driven by atmospheric nutrient deposition and shifts towards tree species with high-quality litter, pose risks such as vegetation ruderalisation and suppression of nutrient-sensitive oligotrophic species. This study presents the first experiment combining canopy opening with litter removal, a strategy potentially reducing nutrient loads, in a species-rich oak-hornbeam forest in Central Europe (Czech Republic). We established a split-plot experiment with two partially thinned plots (30 % canopy openness), comprising 8 paired subplots: one with litter removal and the other as a control. Paired plots were also established in an adjacent closed-canopy forest. Regardless of litter removal, vascular plant richness increased significantly in open-canopy plots by the second year, with the highest richness observed in open-canopy plots with litter removal from the third year onwards. RLQ analysis combining compositional data with species traits revealed a clear effect of canopy opening, while also showing that litter removal in thinned plots favoured oligoand mesotrophic species typical of open habitats, such as thermophilous oak woodlands and dry grasslands. In contrast, nutrient-demanding species characterized by greater plant height were favoured in thinned plots where litter was retained. Litter removal had no significant effect in the closed-canopy forest, suggesting its effectiveness depends on sufficient light availability. Our findings show that combining canopy opening with litter removal can prevent vegetation ruderalisation and support the establishment of target understorey species of open woodlands.

ABSTRACT Rveg is an open‐source package extension for the R statistical programming language, designed to facilitate the efficient and straightforward digitization of phytosociological relevés (vegetation plot observations) into plain comma‐separated values (CSV) format. This format is easily importable into the R environment for data editing and analysis. Rveg distinguishes itself through enhanced efficiency, simplicity, and accessibility compared to alternative software solutions.

Understanding the seasonal dynamics of the forest herb layer and the factors that influence it is essential for predicting how the forest ecosystem, including mutualistic interactions, will respond to global change. However, to date, no research has investigated how understorey phenological guilds respond to major environmental threats and forest interventions. We showed the marked changes in the phenological structure of floodplain forest plant communities over half a century at a multi-regional scale in Central Europe. Unlike previous studies focusing on individual species' responses to climate change, we examined shifts in species richness, frequency and abundance between phenological guilds within the plant community. We examined the effects of temporal variation in climate, hydrology, soil conditions and canopy structure, and assessed the effects of non-intervention and intervention management on phenological guild responses. Our results show a significant loss of local species richness and a decline in species frequency in the forest understorey vegetation, associated with species exhibiting summer phenology. In contrast, an increase in abundance and richness of spring flowering species was observed, attributed to high nutrient loads and reduced flooding, respectively. The abundance of spring species increased only in stands where canopy cover increased over time, probably due to the suppression of summer flowering species, allowing spring flowering species to spread on open, bare ground. The community experienced a shift in maximum flowering plant richness from June to May. Despite management interventions such as clearcutting and tree planting, our data show similar temporal trajectories in intervention and non-intervention forests, indicating that changes in phenological structure are largely independent of recent management activities. Synthesis. We propose that a complex interplay of environmental factors, rather than climate change alone, is shaping shifts towards earlier phenological guilds in floodplain forests. This study highlights the importance of considering a comprehensive view of phenological guild dynamics and the impact of environmental factors on forest plant community structure in the face of global change. We propose that a complex interplay of environmental factors, rather than climate change alone, is shaping shifts towards earlier phenological guilds in floodplain forests. This study highlights the importance of considering a comprehensive view of phenological guild dynamics and the impact of environmental factors on forest plant community structure in the face of global change.image

AimA resource based conceptual model of plant diversity (RBCM) assumes direct relationships between resource supply and the diversity of a local plant assembly. However, the RBCM largely ignores variation in soil toxicity imposed by climatic effects. Both soil limiting resources and soil toxicity vary along climatic gradients but their net and interactive effects on plant species diversity remain unknown. We asked how climatic gradients shape resource availability, soil toxicity and dominance of herb-layer graminoids, and how these predictors control local species diversity of herbs and bryophytes.LocationSwamp forests, Central Europe.TaxonVascular plants, bryophytes.MethodsAlpha taxonomic diversity of vascular plants and bryophytes was counted for 101 vegetation plots sampled in temperate swamp forests distributed along an 800-km geographical gradient across the Continental, Alpine and Pannonian biogeographical regions. Path analysis (structural equation modelling) was used to quantify the direct and indirect effects of climatic variable (potential evapotranspiration; PET), limiting resources (soil N/P, Ca, C/N, proxies for light and water availability) and soil toxicity (Mn) on graminoid dominance and community diversity.ResultsPET negatively influenced species richness of both groups analysed either directly or indirectly through its positive effect on the cover of graminoid species. Alpha diversity of herbs was additionally reduced by soil toxicity (Mn). Limiting resources correlated either with species dominance (canopy shading, soil Ca) or with PET (soil N/P ratio), but they did not control species richness pattern.Main ConclusionsClimate, soil toxicity and species dominance determined alpha diversity instead of the expected importance of soil limiting resources. These results are key to advancing the theoretical framework of the RBCM. Increased soil toxicity (Mn) in well-watered regions favours the dominance of plant competitors at the expense of less tolerant species. This implies a potential threat to wetland diversity under ongoing climate change.

Long-term time series are increasingly used to assess the effects of global change on plant community diversity and to guide management of target plant communities. However, historical biodiversity data may contain neglected sources of error that can have a significant impact on the results and their interpretation. In our study, we focus on historical sampling error, a source of potential bias in long-term biodiversity assessments that has not been systematically addressed. We resampled two historical datasets of a different origin in the floodplain forests of the Czech Republic, with 534 vegetation plots originally sampled in the 1950s and 1960s. We compared temporal trends in alpha diversity and Ellenberg indicator values (EIVs) between the two parallel surveys. To assess compositional differences, we compared temporal changes in species frequencies. Alpha diversity increased by 9.3 % in one resurvey, but decreased by an average of 30.8 % in the second resurvey. The distribution of EIVs for plots also differed, indicating that each resurvey covered a different part of the environmental gradient. We conclude that preferential historical sampling of the vegetation-environment continuum and species omission may have contributed to the differences in biodiversity and environmental change between the datasets. Our study shows that historical sampling error can have a significant impact on assessments of long-term biodiversity trends. We recommend that historical reference datasets should be critically assessed for potential sources of error in assessments of environmental change and management objectives.

Floodplain forests offer a diversity of habitats and resources for a very wide range of plant and animal species. They also offer many benefits to humankind and are considered essential to the mitigation of the effects of climate change. Nevertheless, throughout the world they are suffering the most intense of anthropogenic pressures so are, of all ecosystems, among the most endangered. Here, we bring together and synthesise existing ecological understanding of the mechanisms underlying the high heterogeneity and diversity of temperate floodplain forests and of the pressures threatening their high biological value due to habitat homogenisation. Floodplain forests depend on the periodic disturbances under which they evolved, including fluvial dynamics, traditional management practices and the activities of herbivores. However, they have been heavily degraded by climate change, invasion of exotic species, river-flow regulation, landscape fragmentation, eutrophication and the cessation of traditional management. We can now observe two general trends in temperate floodplain forests: (1) Due to intensive landscape exploitation, they are now more open and thus prone to the spread of competitive species, including of invasive exotics and (2) Due to the cessation of traditional management, along with modified hydrological conditions, they are composed of species in the later successional stages (i.e., more shade-tolerant and mesic) while light-demanding species are quickly vanishing. Restoration practices have brought about contrasting results when restoration of floodplains to their natural states has been problematic. This is likely because of interplay between various natural and artificial processes not previously taken into proper consideration. We would like to draw attention to the fact that restoration projects or the preservation of existing floodplain forest ecosystems should combine the restoration of watercourses with the mitigation of other important threats acting at different scales of the landscape (spread of invasive species, eutrophication of watersheds and inappropriate forest management).

Open forests are among the world's most species-rich ecosystems but these are now suffering from strong environmental pressure. With the increasing frequency of drought events accompanying climate change, open forests are now at high risk of canopy openness, an associated increase in nutrient load, and a consequent reordering of the plant community. Based on an 11-year field manipulative experiment, we examined whether the reintroduction of traditional forest uses, in particular the regular removal of litter which has been practiced for many centuries in Europe, may mitigate eutrophication and protect the ancient plant diversity of open forests. We examined vascular plant composition in 64, 3 x 3 m plots in 32 randomized blocks, each consisted of one litter-removal and one control plot in a subcontinental thermophilous oak forest dominated by Quercus petraea (Czech Republic, Central Europe). We analyzed how regular litter removal influenced the changes in topsoil nutrients and diversity and abundances of perennial, short-lived monocarpic and open oak forest plant species after eleven years of the annual application of this management. The regular litter removal significantly miti-gated eutrophication by a reducing total nitrogen, and significantly decreased the amounts of base cations Ca2+ and Mg2+ in the topsoil. The studied plant species groups responded differently. Perennial and open oak forest species significantly increased their richness and abundances in the litter-removal plots and at the same time their diversity did not change significantly depending on inter-annual weather conditions. In contrast, litter removal negatively affected abundances of short-lived monocarpic species, whose richness was also considerably influenced by weather conditions (decreased the most in years with spring droughts). Moreover, we have found a protective effect of regular litter removal on drought-sensitive open oak forest species that survived in the litter -removal plots, whereas some completely disappeared from control sites during the period of repeated drought events. Our study thus demonstrates that litter removal is a tool with high potential in maintaining biodiversity in open forests affected by climate change.

The biogeographic origin of the species‐rich steppe grasslands in central Europe has long been debated. The alternative hypotheses are long‐term species persistence in situ versus immigration from the south‐east, either after the last glacial maximum (LGM) or after the Neolithic landscape deforestation. We ask whether macroclimate‐based models of habitat suitability support either of these hypotheses and search for macroclimatically suitable ‘source areas' from which species could colonise the areas occupied in Europe today. We modelled habitat suitability for 104 species of the central European steppes and projected these models to 10 periods between the LGM and the present using downscaled CCSM3 simulations. By simulating postglacial migration, we identified potential source areas for each species in the LGM and mid‐Holocene and examined whether their location differed among three ecological and five chorological species groups. The central European macroclimate during the cold phases of the Late Pleistocene was suitable for species now typical of Asian desert steppes, whereas the warmer Bølling–Allerød and Holocene macroclimates supported the occurrence of present‐day central European steppe flora. The models suggest that the LGM source areas of these species ranged from south‐eastern France through the Adriatic region and the Balkan Peninsula to the Black‐Sea region but extended to central Europe in the mid‐Holocene. Their locations differed considerably among ecological and chorological groups in both periods. Therefore, our models support the hypothesis that during the Pleistocene cold periods, the largest populations of these species occurred in southern and south‐eastern Europe and some of them may have later colonised central Europe. If some populations occurred in central Europe during the LGM, as suggested by recent genetic analyses, they were likely restricted to microrefugia embedded in the landscape matrix of species‐poor cold steppe. The precipitation‐rich mid‐Holocene climate had no direct negative impact on the central European steppe flora.

The diploid A. glutinosa (L.) Gaertn. is widespread throughout the European continent, except in the Iberian and Balkan Peninsulas where tetraploid populations have been discovered. We focused on the tetraploid species described as A. rohlenae Vít, Douda and Mandák that occupies the western part of the Balkan Peninsula, where it has likely completely replaced the diploid species. While the distribution range of the diploid A. glutinosa s. str. is well known, the exact distribution range of the tetraploid A. rohlenae is unknown. Here, we report the first exact distribution of the tetraploid A. rohlenae and the anticipated hybrid zones in which it is in contact with diploid populations using flow cytometry and morphometrics. Tetraploids are located primarily in the mountainous parts of the study area and towards the lowlands are gradually being replaced by diploids, forming a contact zone. We compare the main morphological characteristics of both species. Due to the geographical proximity of the study species, the morphological differences between them are clear outside the contact zones. However, within the contact zones, we recorded hybridisations that obscure the morphological differences between species, probably due to the presence of triploid hybrids.

Disturbance regime and site productivity are considered the main factors shaping plant species assemblages and community diversity in riparian ecosystems, but whether and how topographic indices correlate with these two predictors remains largely unexplored. In this study, the stream power index (SPI) and topographic wetness index (TWI) were calculated as surrogates of flooding-induced disturbances and site productivity, respectively. We used a robust dataset of 879 vegetation plots sampled in temperate floodplain forests of Slovakia with the goal of testing the predictive power of interactions between the SPI and TWI on the diversity patterns of all vascular plants, ferns, woody species, aliens, neophytes and Red List species. Generalized additive models (GAMs) revealed the complementary importance of both predictors for explaining the species richness of different plant guilds in floodplain forests, including non-native and Red List species. The SPI and TWI accounted for 4.0–42.0% of the variation in species richness data, depending on species group, with the highest variation explained for ferns and the lowest variation explained for Red List species. Our results indicated that higher flooding-induced disturbances (SPI) associated with light availability increased the number of all species. Their richness declined towards less disturbed (SPI) sites with higher productivity (TWI) levels, where a higher rate of interspecific competitive exclusions is expected. In contrast, the species-reducing effect of frequent flooding (SPI) was recorded for aliens, neophytes and woody richness, with maximum richness values found at more productive sites. These trends differed from the patterns recognized for Red List species richness, which peaked at the intermediate disturbance (SPI) and productivity (TWI) levels. Our findings suggest that river networks with natural flow regimes and recurring episodes of floods facilitate species richness and simultaneously make riparian forests more resistant to plant invasions than regulated or channelized rivers. We confirmed that topographic indices represent tools for estimating the biodiversity status of floodplain forests, which could be useful in regions with a low rate of vegetation sampling or with insufficient cost and personnel capacities for vegetation monitoring. The TWI and SPI, as easily calculated measures, could be effectively applied to identify areas with various conservation and management targets.

River valleys are considered natural corridors for migration of plant species; however, there is a lack of studies confirming higher colonisation rates of plant species in these areas. We compare plant species richness between ancient and recent forests (developed during and after the nineteenth century) and those located in a river valley with those located outside the river valley. We hypothesise that, close to a river, higher plant species richness will be associated with recent forests, thus indicating a higher colonisation rate. The study area includes parts of the Elbe River Valley and a landscape outside the river valley in the Czech Republic. We sampled an equal number of recent and ancient forests (20/20), but lying at different distances from the river. We used generalised linear models to test the effect of distance from the river in dependence upon forest continuity (recent/ancient forest) on two plant species richness categories, i.e. richness of forest species and overall species richness. Outside the river valley, higher richness of forest species was associated with ancient forests, whereas overall species richness was comparable. In the river valley, richness of forest species as well as overall species richness was higher in the recent forests. Recent forests in the river valley were more saturated by plant species than those outside the river valley, indicating that in the river valley, the colonisation rate of plant species is higher. These results confirm the importance of river valleys as natural corridors for migration of plant species.