Red (Acer rubrum) and silver maple (Acer saccharinum) flower before leafing out in the early spring, making them vulnerable to post-budbreak freezing (false springs), a risk climate change exacerbates. They also show interannual variation in fruit production (masting), but it is unknown whether this pattern is related to freezing damage after budbreak. We observed budbreak phenology and measured cold hardiness of floral and vegetative buds of both maple species from dormancy to spring budbreak in 2024 and 2025. We also collected buds three times in 2025, incubated them in growth chambers up to 22°C, and quantified their deacclimation velocity. Finally, we used regional phenological data to assess whether local variation in fruit production might depend on false spring risk. We established the physiological context of spring budbreak in our study species: Silver maple floral buds open first and when very cold hardy, need minimal chilling, and lose cold hardiness rapidly; red maple vegetative buds open last and when least cold hardy, need considerable chilling, and lose cold hardiness slowly; and red maple floral buds and silver maple vegetative buds are intermediate. Though low fruit production was found to correlate with warm March temperatures followed by late March cold spells, we did not find direct, mechanistic evidence that local cold weather killed floral buds, decreasing fruit production. Differential physiology of maple buds interacts with climate to determine phenology. Both study species are at low risk of false spring damage, although it is unclear whether and how variable spring weather affects masting dynamics.

The geographical distributions of established nonindigenous forest insects and pathogens have historically not been well documented nor centrally aggregated, the absence of which has contributed to constrained efforts to manage and minimize resultant damages. To address this need, we present the construction of a centralized database accessible via a publicly available web portal, the Alien Forest Pest Explorer. All nonindigenous forest insect and pathogen species known to cause economic impacts in the conterminous U.S. were selected for inclusion in the database. The occurrence of these established pests, which is derived from a variety of data streams including reports by state and Federal agencies, the scientific literature, and biodiversity databases, is recorded at the county level. In addition to data on geographical distribution of the pests, the database also provides county-level data that quantifies the volume of host trees species derived from forest inventory data. Overall, the data and analyses presented here provide baseline information regarding the distribution of nonindigenous forest pests and changes in host resources. Our database can also help to provide a more complete understanding of the impacts of nonindigenous forest pests on U.S. forests and can be used as a public resource in supporting regional invasive forest pest research and management. The data are available for reuse under CC0 1.0 Universal licensing; however, we appreciate the citation of this data paper when reusing the dataset.

The three datasets provide occurrences, functional traits, and conservation status for the vascular plants of the Maritime and Ligurian Alps (Italy and France), one of the major biodiversity hotspots in the Mediterranean basin and the primary center of endemism in the Alps. The presence of each taxon was verified through national and international databases, as well as through validation by experts specialized in regional vascular flora and on specific taxonomic groups. The first dataset includes 3521 taxa, comprising 3309 species and 212 subspecies, belonging to 924 genera and 153 families. For each taxon, we provide detailed taxonomical information (phylum, class, family, genus, and taxon rank). To reconcile nomenclatural differences between Italy and France, we standardized the nomenclature according to the International Plant Names Index, reporting national synonyms where available. In the second dataset, we compiled information on the main reproductive, morphological, ecological, and biogeographical features of the taxa. Data were retrieved from Baseflor, FloraVeg.EU, GIFT, SID, and TRY databases and complemented, when necessary, with data from regional and national flora, including Flora d'Italia, Flora Gallica, and Flora Alpina. Information for 21 traits is available for 2032 taxa (57.7%). We successfully assigned at least 19 traits to 842 taxa (23.9%). Another 544 taxa (15.4%) have between 2 and 18 traits, while 99 (2.8%) have between 5 and 10. Fewer than two traits are identified only for three taxa. Two taxa had no trait data available. Life forms and growth forms were the traits with the least missing data (assigned in 99.8% and 99.7% of the taxa, respectively), while seed mass showed the least data (present in 77.9% of the taxa). Plant functional traits are key drivers of ecosystem functioning and vegetation dynamics; therefore, understanding these traits is crucial for predicting how present vascular flora will respond to global warming and anthropogenic pressures in the future. A third dataset was compiled including the IUCN red lists together with international, national, and regional protection with the aim of providing a tool to guide future measures for the conservation of this vascular flora and its habitats, also with the occurrence of invasive or naturalized allochthonous species. Importantly, this will support the development of coordinated management and conservation strategies across two national borders, highlighting the need for a transnational approach to vascular flora and habitat conservation in the Maritime and Ligurian Alps. The three datasets are designed to be continuously updated, through their integration with new data on species occurrence, functional traits, and conservation status as these become available to the scientific community. Together, they provide a robust baseline for future research on plant evolution and vegetation dynamics and responses to global changes. Furthermore, these datasets will enhance data consistency and support informed decision-making and policy development in response to the emerging threats to plants and habitats posed by global warming. By making these data openly available, we adhere to FAIR principles (Findable, Accessible, Interoperable, and Reusable), supporting open research in conservation and macroecology. The data are available for reuse under CC BY 4.0 licensing. Please cite the data release and this data paper when reusing the dataset.

Ongoing climate change will negatively impact tree populations unless they are able to acclimate to the changes in their local environment. Effective planning for climate adaptation management requires an understanding of the current state of local adaptation and physiological performance to assess whether populations are at risk of local extinction, to determine if seed movement is appropriate, and to select appropriate seed sources if intervention is needed. We established a new reciprocal transplant experiment (Adaptation to Climate and Environment [ACE]) across a latitudinal gradient in North America spanning a range of climate and soil conditions to examine the impacts of warming on three bur oak (Quercus macrocarpa) populations across much of the species' range. We established common gardens in Minnesota, Illinois, and Oklahoma in 2021 grown from seeds collected in 2018-2019 within 50 km of each of those locations from a total of 60 maternal families. In 2023, we measured physiology and 3-year growth and survival to understand local adaptation in bur oak populations. We aimed to (1) assess local adaptation in each of the populations using survival and size as fitness metrics and (2) evaluate physiological responses to different environments along the latitudinal gradient. We found evidence for local adaptation of the southern population in the southernmost garden, but that the northern populations were maladapted to high levels of warming, as evidenced by their low survival, growth, and photosynthetic rates in the warmest common garden. However, mild climate and relatively high nutrient conditions in the middle garden resulted in the highest fitness and best physiological performance for all populations. Growth and survival were correlated in the middle garden but were decoupled in the northern and southern gardens, likely due to stress associated with more extreme climates at the ends of the gradient. Our results suggest that southern seed sources may perform well in warmer conditions in the north brought on by climate change, which has important implications for managers assisting broadly ranged tree species in adapting to climate change.

Datasets describing the composition of biological communities across broad anthropogenic gradients are valuable resources for ecologists and conservation biologists, with applications ranging from testing theories of community assembly to guiding biodiversity management. But much of the most rigorously collected field survey datasets, particularly for vascular plant communities in urban environments, remain underutilized because they are not curated or publicly accessible. We compiled and standardized a large database of information on the composition of vascular plant communities from sites spanning urbanization gradients in 12 cities in northeastern North America. The database integrates 26 field studies conducted by researchers from 1987 to 2024, encompassing 746 sites of either forest (n = 408 sites) or open habitat (e.g., meadow, prairie, vacant lot; n = 338 sites). Forest sites include canopy (overstorey) and ground (understorey) layers, while open habitats only include a ground layer. Field sites span a gradient of urbanization from rural to urban areas and are characterized as being minimally managed in situ at the time of surveys. Thus, the data are representative of spontaneous vegetation that was not seeded or planted. In total, the database contains records for 1296 taxa identified to the species level, including 322,101 presence/absence records and 23,805 abundance records, all geo-referenced and accompanied by metadata on site area, sampling effort, site management, site history, and methodology, all of which varied by site. To ensure consistency across studies, taxonomic names were standardized according to the Database of Vascular Plants of Canada (VASCAN), and all measurements were summarized at the site level. Unlike presence-only data commonly available from citizen science repositories, this database provides both presence/absence and abundance records collected through systematic surveys. As a result, it avoids many of the pitfalls associated with citizen science data such as opportunistic sampling, bias towards public/highly frequented sites, lack of a complete record of all species in a community, and misidentifications by nonexpert observers. It also enables analyses that would otherwise be difficult or impossible, such as studies of species abundance, community composition, rare taxa, and species of low desirability. Overall, this database offers a valuable resource for those interested in studying plant community dynamics and the impacts of urbanization and other anthropogenic gradients on biodiversity. The data are available for reuse under CC0 1.0 Universal licensing; however, we appreciate the citation of this data paper when reusing the dataset.

Plants that resprout after fire experience drastically altered conditions in post-fire environments. However, the effects of plant exposure to fire on offspring traits remain understudied. Many resprouting species are herbaceous plants that flower and fruit rapidly after fire (i.e., fire-stimulated flowering), developing their seeds under increased resource availability and modified biotic interactions, particularly enhanced pollination. We hypothesize that these changes may improve early offspring development through maternal provisioning and increased quality of floral visitation and pollen deposition. To test this, we selected three Mediterranean geophytes (Asphodelus cerasifer, Drimia maritima, Narcissus assoanus) and compared seed mass (3161 seeds) and total germination (2262 seeds) between paired burned and adjacent unburned plants during the first post-fire fruiting season, sampling six populations over 4 years. Although responses varied among localities and species, on average, seeds from burned plants were 13.9% heavier and had a 16.9% higher germination than those from unburned plants. Our results demonstrate that plant exposure to fire can enhance seed mass and germination and suggest that these improvements may be largely influenced by maternal effects. These fire-driven increases in offspring performance may have important consequences for recruitment, regeneration dynamics, and the long-term persistence of plant populations in fire-prone ecosystems.

Predation is a fundamental ecological process. Social learning by predators is ubiquitous. However, social learning is not incorporated into most ecological theories of predator-prey dynamics. We report how social learning changes results of classic one-predator, two-prey models. In our study, one prey (familiar) can be innately exploited by any predator. The other prey (novel) can only be exploited by predators that have learned how to consume it (i.e., informed predators). Social learning converts naïve predators into informed predators via mass action. This governs exploitation of the novel prey. Indirect effects such as apparent competition then emerge among familiar and novel prey. We find that the novel prey is a superior apparent competitor to the familiar prey because it has a refuge from naïve predators. Faster social learning helps the familiar prey coexist because it erodes this refuge. Other outcomes, such as apparent mutualism and apparent predation, occur when the system exhibits limit cycles. Social learning tends to dampen cycling relative to classic models of apparent competition, but can also exaggerate indirect effects. Our theory is applicable to biological invasions, where it predicts that social learning may determine the persistence of invaders and native species.

Podocarps (Podocarpaceae) are one of the few lineages of conifers found in closed canopy tropical forests. They typically have highly restricted distributions that are associated with nutrient-poor sites. Unlike other tree species, the presence of distinct nodule-like structures allows their roots to be easily distinguished from those of co-occurring taxa. In highly infertile ever-wet lower montane forest at Fortuna, Panama, roots of Podocarpus oleifolius occur in three microsites: in the soil; lying on top of surface litter; as aerial roots that climb the trunks of neighboring trees. We examined how microsite affects Podocarpus root fungal community composition by sequencing the internal transcribed spacer (ITS) region, and by measuring root nutrient concentration and phosphatase enzyme activity. We also compared Podocarpus roots collected from the soil with those of two common co-occurring angiosperm trees, Graffenrieda bella and Weinmannia pinnata. We found that root microsite accounted for 11% of the variation in root-associated fungal communities and also affected root calcium, potassium, and manganese concentration. Root fungal diversity, phosphate concentration, and phosphatase activity were unchanged. Across all microsites, the fungal order Helotiales accounted for 50%-60% of ITS reads, while aerial roots had significantly higher abundance of Trechisporales. When comparing across species, Glomeromycota were only detected in very low numbers overall (1.8%-3.3% of reads in angiosperms), and were especially low in Podocarpus (0.14% of reads). In contrast, Podocarpus had a higher fraction of reads belonging to Leotiomycetes than Graffenrieda and Weinmannia. Our findings highlight how root-associated fungal communities vary at the order level with microsite and host species in tropical montane forest. In continuously cool, low-nutrient wet environments, where nutrients are rapidly leached from throughfall, or are mineralized slowly from decomposing organic matter, alternatives to arbuscular mycorrhizal fungi may be especially advantageous to plants. Biotrophic fungi in the Helotiales have been implicated in nutrient transfer in alpine and arctic environments, and together with Trechisporales, may be key unrecognized mutualistic partners in the tropics. Collectively, these taxa may explain the association of podocarps with low-nutrient montane forest.

Wildlife populations worldwide are increasingly exposed to climatic extremes, yet demographic mechanisms linking environmental variability to local extinction remain poorly understood. We evaluated the population dynamics of a degu (Octodon degus) population in central Chile over a 12-year period (2009-2020) encompassing a decade-long megadrought. Using capture-mark-recapture models, we estimated apparent survival, recruitment, and population growth rates and assessed their relationships with climatic and ecosystem variables. Population growth remained positive throughout most of the study period despite prolonged drought conditions, indicating resistance to long-term environmental stress. However, in 2019, an extreme drought year with markedly reduced precipitation and resource availability, gross primary productivity (GPP) crossed a critical threshold (a tipping point). As a result, survival and recruitment declined sharply, the population underwent an abrupt state shift and rapid collapse, and ultimately went locally extinct. Our analyses indicate that variation in GPP was the strongest predictor of both survival and recruitment, highlighting the importance of resource availability in mediating demographic responses to drought. These results show that the extreme environmental conditions in 2019 acted as the proximate driver of extinction, rather than a cumulative effect of the preceding megadrought. We discuss how species-specific traits, including short lifespan, seasonal reproduction, and social organization, may limit the ability of degus to buffer consecutive demographic failures under extreme conditions, contributing to threshold-like population collapse. Our findings suggest that populations may persist under prolonged adverse conditions yet remain vulnerable to rare but severe environmental events, emphasizing the importance of extreme climatic variability in driving local extinction risk.

Predicting how populations respond to environmental change remains a central challenge in ecology. While temperature is widely recognized as a major determinant of organismal performance, population responses to thermal stress are also shaped by biotic interactions. Intraspecific competition, in particular, can impose energetic and density-dependent constraints that influence life history traits underlying individual and population fitness. Yet, despite its ecological importance, little is known about whether competition history alters offspring responses to subsequent environmental stress across generations. Here, we investigated how parental competition history shapes offspring responses to cool thermal stress across multiple generations in the marine nematode Litoditis marina (Pm III). Populations were maintained for nine generations under contrasting competition regimes and offspring were subsequently evaluated at either an optimal temperature (20°C) or a cool suboptimal temperature (15°C), representing a deviation below the species' thermal optimum. Cool thermal stress consistently reduced offspring performance, but its effects depended strongly on parental competition history. Under optimal conditions, offspring originating from high-competition populations exhibited slower development but partially compensated through increased fecundity. Under cool thermal stress, however, this compensatory response disappeared: Offspring from high-competition populations showed lower fecundity and reduced population growth relative to offspring from low-competition populations, with these differences becoming increasingly pronounced across generations. Across all measured traits, offspring originating from high-competition populations exhibited slower development, lower reproductive output, and reduced demographic performance under cool thermal stress. These findings demonstrate that parental competition history can strongly influence offspring responses to subsequent environmental challenges and contribute to persistent multigenerational differences in population performance. Our results identify biotic environmental history as an important determinant of population responses to environmental change and highlight the need to integrate both ecological interactions and abiotic stressors when predicting population resilience under future environmental conditions.

Direct observations from submersible dives off the Galapagos Islands have revealed that Pelagothuria natatrix, the only known holopelagic echinoderm, actively intercepts settling particles well before they can reach the deep seafloor, thereby short-circuiting the typical downward flux of organic carbon generated in the photic zone.

Predators can affect ecological communities not only through direct consumption but also by indirectly triggering costly defensive responses in prey that cascade through food webs. Understanding how prey navigate the competing demands of predation pressure and resource exploitation is thus central to predicting ecological (i.e., persistence) and evolutionary (i.e., adaptation) dynamics. Drawing on niche theory and the influence of keystone predators, this study investigates how variation in resource availability drives the persistence and evolution of prey with diverse trait combinations balancing defensive and competitive traits. At the heart of this ecological puzzle lies a fundamental constraint: Defended prey inherently have lower competitive abilities, generating a trade-off that governs fitness success along environmental gradients. Using a mathematical model, we show that the shape of the defense-competitiveness trade-off (i.e., the magnitude of change of competitiveness costs with increasing defense) influences the persistence of prey populations and the evolution of prey competitive and defensive traits. Strong trade-offs (i.e., when defenses strongly reduce competitiveness) or neutral trade-offs (i.e., when gains in defense and losses in competitiveness change proportionally) favor competitiveness, while weak trade-offs (i.e., when defenses weakly affect competitiveness) favor defensive traits, especially in resource-rich environments. In resource-poor environments, however, competitive prey are predominantly favored. Coexistence among prey individuals with different resource allocation strategies is evolutionarily unstable, as our model revealed that evolutionary processes eroded the persistence of multiple prey strategies. By linking resource availability to prey trait evolution, this study highlights the environmental dependence of eco-evolutionary dynamics in food webs, offering insights into the complex interactions that drive the prevalence and evolution of defense strategies.

Understanding the diversity and adaptive significance of oviposition-related behaviors is crucial for understanding how insects cope with the limited mobility of their offspring. In this study, we focused on the oviposition behavior of the longhorn beetle Schwarzerium quadricolle (Coleoptera: Cerambycidae, and observed a unique phenomenon: hatching larvae remain within their eggshells, where they feed on host wood before boring into branches.

The distributions of rare species are often estimated from presence-absence data, but undetected occurrences (imperfect detection) can lead to consequential underestimates of occupancy. Despite its standard use in animal ecology, detection probability (p) is rarely incorporated into plant occupancy estimates. Plants with cryptic life stages or traits (e.g., seed banks, dormancy) may be especially prone to periods of unobservability, resulting in imperfect detection even when a species is present. We tested the hypothesis that cryptic traits lower detection by reviewing published estimates of p in plant systems. While taxa with cryptic traits, particularly annual plants with seed banks and deciduous geophytes, exhibited lower p, there was wide variation across genera and publications. We then conducted a case study of the rare, annual, aquatic plant, Gratiola amphiantha (snorkelwort), endemic to ephemerally rain-filled granite rock outcrop pools, to estimate occupancy (Ψ), p, and their environmental drivers. We found that Ψ increased with deeper soils and larger pool areas. Snorkelwort exhibited a high but imperfect p (mean p = 0.87) that varied with competing vegetation cover and census date. Modeling Ψ across varying levels of survey effort showed that ignoring imperfect detection can underestimate total occupancy estimates by up to 43%; however, our empirical p estimates indicate a minimum of just two surveys can reach 95% detection for snorkelwort. Our findings demonstrate that imperfect detection is an important and underappreciated limitation in plant occupancy studies, even for species with high detection probability. For rare plants, explicitly incorporating taxon-specific p estimates and marginally increasing survey effort can substantially improve the accuracy of occupancy models.

Historical distribution maps are important as baseline data when assessing biodiversity change. Here, we provide a database with digitized distribution maps originally published in Atlas of the distribution of vascular plants in northwestern Europe (1971) by Professor Eric Hultén. The database contains georeferenced and digitized distribution maps for 1909 vascular plant species in 616 genera and 119 families. In his work, Eric Hultén compiled spatially explicit data from a vast body of knowledge that had been acquired by professional and amateur botanists. Data were collated from scientific publications, local and regional floras and plant lists, species surveys, and herbarium records. The distribution maps cover the Scandinavian peninsula, including the whole extent of Sweden, Norway, Finland, and Denmark. The Baltic countries Estonia, Latvia, and Lithuania are covered in part, as well as parts of Russia and a small part of northern Germany. Given the scale of the original maps, the effective resolution of the range data is 16 × 16 km. The data on which the original ranges were based varied within the area covered, with comparatively less data available for Russia and the Baltic countries. In order to make this important information compatible with modern analyses, we developed an automated method combined with manual data cleaning to georeference and extract distribution data from the printed maps. The digitized distribution maps are available as spatial polygon features (GeoJSON), which can be converted into gridded or regional occupancy data for each species using the code provided. The digitized polygon range maps in the dataset can be used to illustrate historical distributions of specific species, and when converted to occupancy data, they can be used as baseline distributions in any type of niche or distribution model. In combination with current occurrence records, the historical data can also be used to assess distribution change for the entire assemblage of vascular plants, generating important insights on the drivers of biodiversity change. If, in addition to its scientific and practical value, it can also contribute to keeping the study of »scientia amabilis»-the lovable science, as Eric Hultén himself phrased it-alive, then its purpose has been achieved. The data and code are released under a Creative Commons Attribution 4.0 International (CC BY 4.0) license.