Genetic and epigenetic changes during the invasion of a cosmopolitan species (Phragmites australis)

While many introduced invasive species can increase genetic diversity through multiple introductions and/or hybridization to colonize successfully in new environments, others with low genetic diversity have to persist by alternative mechanisms such as epigenetic variation. Given that Phragmites australis is a cosmopolitan reed growing in a wide range of habitats and its invasion history, especially in North America, has been relatively well studied, it provides an ideal system for studying the role and relationship of genetic and epigenetic variation in biological invasions. We used amplified fragment length polymorphism (AFLP) and methylation‐sensitive (MS) AFLP methods to evaluate genetic and epigenetic diversity and structure in groups of the common reed across its range in the world. Evidence from analysis of molecular variance (AMOVA) based on AFLP and MS‐AFLP data supported the previous conclusion that the invasive introduced populations of P. australis in North America were from European and Mediterranean regions. In the Gulf Coast region, the introduced group harbored a high level of genetic variation relative to originating group from its native location, and it showed epigenetic diversity equal to that of the native group, if not higher, while the introduced group held lower genetic diversity than the native. In the Great Lakes region, the native group displayed very low genetic and epigenetic variation, and the introduced one showed slightly lower genetic and epigenetic diversity than the original one. Unexpectedly, AMOVA and principal component analysis did not demonstrate any epigenetic convergence between native and introduced groups before genetic convergence. Our results suggested that intertwined changes in genetic and epigenetic variation were involved in the invasion success in North America. Although our study did not provide strong evidence proving the importance of epigenetic variation prior to genetic, it implied the similar role of stable epigenetic diversity to genetic diversity in the adaptation of P. australis to local environment.     

Cryptic lineages and potential introgression in a mixed-ploidy species (Phragmites australis) across temperate China

Polyploidization and hybridization are very common in natural plant species, and mixed-ploidy species provide a unique opportunity to study the effects of evolutionary history, local abundance, and ploidy level on the direction and extent of introgression between intraspecific lineages. First, we delimited two morphologically cryptic lineages of Phragmites australis Trin. ex Steud. in temperate China using 11 nuclear microsatellites and two chloroplast DNA fragments with 225 samples from China as well as 11 samples from Oceania and Europe. Our evidence supported that haplotype O and haplotype P were two relatively independent lineages with low and high ploidy levels, respectively; haplotype M might be ancient and could have undergone a complex evolutionary history. Then we examined the lineage divergence and compared the introgression patterns between two major lineages along geographical and abundance gradients with a large number of samples (n = 1067) collected from China. The sympatric coexistence of two lineages in north and northeast China implies an ongoing or potential introgression between them. Cline analysis showed that the level of genetic admixture were significantly correlated with longitude rather than latitude. Our results also suggested that ploidy level could deeply influence the introgression asymmetry, and the effect of the current local abundance on introgression might be covered by the past coexistence time driven by phylogeographic history. Our study draws a baseline for future research on the ecological and evolutionary consequences of migration and introgression of Chinese P. australis under global change.     

若尔盖不同生境植物多样性与植物竞争强度和生态位重叠度的关系

植物多样性与植物竞争强度和生态位重叠度的关系会随环境发生变化。为探究上述关系在若尔盖地区的表现形式,于2021年8月对若尔盖地区典型的水生、湿生、湿生-中生和中生植物群落进行调查,构建了新的植物竞争强度（Competition intensity,CI）公式并进行测算,计算了植物群落的植物多样性指数（包括物种丰富度、Shannon-Weiner指数、Simpson指数和Pielou均匀度指数）和生态位重叠度（Niche overlap of species,NOS）,分析了植物群落物种多样性指数与CI和NOS的关系。结果表明：1）从水生到中生生境,植物多样性指数均呈增加趋势（P<0.05）;2）湿生-中生生境的CI显著高于湿生生境（P<0.05）,湿生生境的NOS高于水生生境（P<0.05）;CI与NOS无显著相关性,但在湿生生境中两者呈倒抛物线关系（P<0.05）。3）整体来看,植物群落的物种丰富度与CI呈抛物线关系（P<0.05）,与NOS无显著关系（P>0.05）;Shannon-Weiner指数、Simpson指数和Pielou均匀度指数均与NOS呈线性正相关（P<0.05）,与CI无显著关系（P>0.05）;从单个生境看,湿生-中生生境的Simpson指数、Shannon-Weiner指数和Pielou均匀度指数与CI呈线性负相关（P<0.05）,其余生境的上述多样性指数与CI无显著关系（P>0.05）;各生境的植物多样性指数均与NOS无显著相关性（P>0.05）。本研究表明,从水生到中生生境,若尔盖地区的植物多样性呈增加趋势,但植物多样性与物种竞争强度和生态位重叠度的关系较复杂。本研究结果有助于理解若尔盖高原植物多样性的形成机制。     

Trophic niche overlap between round sardinella (Sardinella aurita) and sympatric pelagic fish species in the Western Mediterranean

The northward expansion of round sardinella (Sardinella aurita) in the Mediterranean Sea, together with declines and fluctuations in biomass and landings of European sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus) observed in recent decades, may suggest potential inter‐specific competition in the pelagic domain. The coexistence of sympatric zooplanktivorous fish species might therefore be exposed in part to trophic niche overlap and competition for food. Combining visual diet characterization under the microscope with DNA metabarcoding from stomach contents of fish collected in spring results show that predation on relatively large krill is equally important for sardinella than for the other two niche overlapping species. Furthermore, an important overlap is found in their isotopic niche, especially with anchovy, using nitrogen (δ¹⁵N) and carbon (δ¹³C) stable isotopes in muscle tissue. In fact, the three fish species are able to feed effectively in the whole prey size spectrum available during the sampled season, from the smallest diatoms and copepods to the larger prey (i.e., decapods and euphausiids), including fish larvae. Moreover, effective predation upon other large prey like siphonophores, which is observed only when multi‐proxy analyses in stomach contents are applied, might also be relevant in the diet of sardinella. The overlapping diet composition in spring, together with the effective use of food resource by sardinella, can be of special interest in potential future scenarios with warmer water temperature leading to lower zooplankton and/or higher jellyfish availability, where sardinella may take advantage over other species due to its feeding plasticity.     

Food utilization and niche overlap in three species of lake-dwelling leeches (Hirudinea)

The diets of Erpobdella octoculata, Glosiphonia complanata and Helobdella stagnalis on the stony littoral zone of eutrophic Crose Mere were examined over two years using the precipitin test. The abundances of food organisms were measured. For all leech species, juvenile mortality was greatest in locations where a low ratio of prey abundance to recruited leech abundance occurred, and the intensity of feeding by Erpobdella and Helobdella fell slightly in late summer when large numbers of juveniles of these species were present; these suggest the involvement of food in juvenile mortality, Seasonal changes in feeding intensity were similar for all leech species, with the exceptions outlined above and for Glossiphonia in April when feeding by brooding adults ceased, at which time the severity of any interspecific competition would have been reduced. Within a leech species, there was little change in the food spectrum as the leeches grew. Niche breadth was lowest for Erpobdella and highest for Helobdella. Niche overlap was greatest between Glossiphonia and Helobdella, and there was a trend for overlap values to be lower between Glossiphonia and Erpobdellu than between Helohdellu and Erpohdellu. Erpobdella fed mainly on chironomids and oligochaetes, Glossiphonia on molluscs, oligochaetes and chironomids, and Helobdella on oligochaetes, chironomids, Asellus, molluses and amphipods, all in decreasing order of importance. It is suggested that coexistence in the leech species may be due in part to Erpobdella and Glossiphonia having 'food refuges' in chironomids and molluscs, respectively, with Helobdellu being more of a general predator.     

Comparing the dietary niche overlap and ecomorphological differences between invasive Hemidactylus mabouia geckos and a native gecko competitor

Hemidactylus mabouia is one of the most successful, widespread invasive reptile species and has become ubiquitous across tropical urban settings in the Western Hemisphere. Its ability to thrive in close proximity to humans has been linked to the rapid disappearance of native geckos. However, aspects of Hemidactylus mabouia natural history and ecomorphology, often assumed to be linked with this effect on native populations, remain understudied or untested. Here, we combine data from ∂15N and ∂13C stable isotopes, stomach contents, and morphometric analyses of traits associated with feeding and locomotion to test alternate hypotheses of displacement between H. mabouia and a native gecko, Phyllodactylus martini, on the island of Curaçao. We demonstrate substantial overlap of invertebrate prey resources between the species, with H. mabouia stomachs containing larger arthropod prey as well as vertebrate prey. We additionally show that H. mabouia possesses several morphological advantages, including larger sizes in feeding‐associated traits and limb proportions that could offer a propulsive locomotor advantage on vertical surfaces. Together, these findings provide the first support for the hypotheses that invasive H. mabouia and native P. martini overlap in prey resources and that H. mabouia possess ecomorphological advantages over P. martini. This work provides critical context for follow‐up studies of H. mabouia and P. martini natural history and direct behavioral experiments that may ultimately illuminate the mechanisms underlying displacement on this island and act as a potential model for other systems with Hemidactylus mabouia invasions.     

Impacts of zebra mussels (Dreissena polymorpha) on isotopic niche size and niche overlap among fish species in a mesotrophic lake

Zebra mussels (Dreissena polymorpha) filter feed phytoplankton and reduce available pelagic energy, potentially driving fish to use littoral energy sources in lakes. However, changes in food webs and energy flow in complex fish communities after zebra mussel establishment are poorly known. We assessed impacts of zebra mussels on fish littoral carbon use, trophic position, isotopic niche size, and isotopic niche overlap among individual fish species using δ¹³C and δ¹⁵N data collected before (2014) and after (2019) zebra mussel establishment in Lake Ida, MN. Isotope data were collected from 11 fish species, and from zooplankton and littoral invertebrates to estimate baseline isotope values. Mixing models were used to convert fish δ¹³C and δ¹⁵N into estimates of littoral carbon and trophic position, respectively. We tested whether trophic position, littoral carbon use, isotopic niche size, and isotopic niche overlap changed from 2014 to 2019 for each fish species. We found few effects on fish trophic position, but 10 out of 11 fish species increased littoral carbon use after zebra mussel establishment, with mean littoral carbon increasing from 43% before to 67% after establishment. Average isotopic niche size of individual species increased significantly (2.1-fold) post zebra mussels, and pairwise-niche overlap between species increased significantly (1.2-fold). These results indicate zebra mussels increase littoral energy dependence in the fish community, resulting in larger individual isotopic niches and increased isotopic niche overlap. These effects may increase interspecific competition among fish species and could ultimately result in reduced abundance of species less able to utilize littoral energy sources.

     

Host-associated differences in fitness within and between populations of a seed beetle (Bruchidae): effects of plant variability

Summary Experiments were conducted with the sexually reproducing seed beetle Stator limbatus and its hosts in north-central Arizona to determine if it was substructured into units, each specialized for higher fitness on a specific host species. Unlike many studies, we incorporated scale, i.e., conducting experiments between and within beetle populations on seeds from within and between plant species. Of particular interest was whether intraspecific plant variability prevented beetle specialization within beetle populations. Results suggest that S. limbatus is specialized to certain hosts. On the palo verde Cercidium floridum, beetles originally reared from this host had significantly higher emergence compared to beetles transferred from other hosts. We did not test directly for a genetic basis for this. Alternative hypotheses of variation in symbiotic microorganisms in larval guts and maternal effects were assessed. Essentially no bacteria, yeast or protozoa were found, and maternal effects as expressed by varying egg weights were not detected; however, other microorganisms might have been present and maternal effects through inducible enzymes was possible. Caution, then, is needed in any genetic interpretations of our results. The differences on C. floridum were detected from tests between and within beetle populations. Evidence for specialization was not detected on the other hosts, Cercidium microphyllum and Acacia greggii. On the other hosts, beetles performed well regardless of their source. Significant differences were detected among individual plants of C. floridum as to the suitability of their seeds for deveoopment of S. limbatus. No such differences were detected among the other host plants. These patterns of conspecific plant variability are opposite of what is expected if plant variability prevents specialization of beetles to particular species of hosts. Thus, the data suggest seed variability among plants does not prevent specialization to host species in this system. We discuss how the patterns of host use in this study relate to the hypothesis of sympatric host race formation.     

Allocation of photosynthestically-fixed carbon in plant and soil during growth of reed (Phragmites australis) in two saline soils

Plant and Soil - Terrestrial carbon (C) sequestration is derived mainly from plant photosysthetically-fixed C deposition but soil organic C (SOC) content in saline soils is generally low due to low...     

High resource overlap and small dietary differences are widespread in food-limited warbler (Parulidae) communities

Although both interspecific competition and coexistence mechanisms are central to ecological and evolutionary theory, past empirical studies have generally focused on simple (two-species) communities over short time periods. Experimental tests of these species interactions are challenging in complex study systems. Moreover, several studies of ‘imperfect generalists’, consistent with Liem's Paradox, raise questions about the ability of evolved species differences to partition niche space effectively when resources vary considerably across the annual cycle. Here we used a recently developed theoretical framework to combine past research on population-level processes with observational data on resource use to test for ongoing interspecific competition and understand the nature of resource overlap. We compared species diet overlaps and differences in several distinctive communities centred on a focal species, the American Redstart Setophaga ruticilla replicated both spatially and seasonally, in combination with documentation of population regulation to assess the ability of similar species to partition dietary niche space and limit interspecific competition. Our results document high dietary overlap in most of the communities studied, with only subtle differentiation consistent with known species differences in foraging behaviour and morphology. These findings are largely consistent with species foraging as imperfect generalists. However, in contrast to past studies, the high diet overlaps observed here during times of inferred resource scarcity were driven by low-value prey taxa (e.g. small ants) and did not involve truly ‘private’ resources. All of these factors increase the potential negative impacts of interspecific competition, and limit the ability of these birds to avoid competition if food availability deteriorates further than observed in our study, either seasonally or at longer intervals.     

Seasonal variation in terrestrial resource subsidies influences trophic niche width and overlap in two aquatic snake species: a stable isotope approach

Quantifying diet is essential for understanding the functional role of species with regard to energy processing, transfer, and storage within ecosystems. Recently, variance structure in the stable isotope composition of consumer tissues has been touted as a robust tool for quantifying trophic niche width, a task that has previously proven difficult due to bias in direct dietary analyses and difficulties in integrating diet composition over time. We used carbon and nitrogen stable isotope analyses to examine trophic niche width of two sympatric aquatic snakes, banded watersnakes Nerodia fasciata and black swamp snakes Seminatrix pygaea inhabiting an isolated wetland where seasonal migrations of amphibian prey cause dramatic shifts in resource availability. Specifically, we characterized snake and prey isotope compositions through time, space, and ontogeny and examined isotope values in relation to prey availability and snake diets assessed by gut content analysis. We determined that prey cluster into functional groups based on similarity of isotopic composition and seasonal availability. Isotope variance structure indicated that the trophic niche width of the banded watersnake was broader (more generalist) than that of the black swamp snake. Banded watersnakes also exhibited seasonal variation in isotope composition, suggesting seasonal diet shifts that track amphibian prey availability. Conversely, black swamp snakes exhibited little seasonal variation but displayed strong ontogenetic shifts in carbon and nitrogen isotope composition that closely paralleled ontogenetic shifts in their primary prey, paedomorphic mole salamanders Ambystoma talpoideum. Although niche dimensions are often treated as static, our results demonstrate that seasonal shifts in niche dimensions can lead to changes in niche overlap between sympatric species. Such short‐term fluctuations in niche overlap can influence competitive interactions and consequently the composition and dynamics of communities and ecosystems.     

Differences in relative air humidity affect responses to soil salinity in freshwater and salt marsh populations of the dominant grass species Phragmites australis

Hydrobiologia - Soil salinity diminishes the dominance of species and affects their distribution. Phragmites australis is a dominant ecosystem engineer with broad distribution, high intraspecific...     

Expansion pathways of the exotic common reed (Phragmites australis): a historical and genetic analysis

Using 779 herbarium and modern specimens, we reconstructed the spread of the common reed ( Phragmites australis ) in Quebec, Canada, where large-scale invasion of this plant species has been reported since the 1960s. All specimens were genetically differentiated using molecular tools to identify the genotype (native or exotic). The exotic genotype (haplotype M) has been present in Quebec as early as 1916, but it was rare prior to the 1970s and was almost exclusively restricted to the shores of the St. Lawrence River. The exotic genotype spread inland only after the beginning of the 1970s. In less than 20 years, a complete shift occurred, from the dominance of native genotypes to the dominance of the exotic genotype. Today, more than 95% of common reed colonies found in Quebec are dominated by the haplotype M. It is especially abundant along roads, but colonies present in marshes are also dominated by the exotic genotype. This study provides evidence that, in Quebec, the development of the highway network in the 1960s and 1970s strongly contributed to the inland expansion of the exotic genotype. Moreover, it shows the usefulness of molecular techniques for reconstructing the spread of an invader. Without the use of molecular tools, the reconstruction of invasions of exotic taxa would be impossible because of the lack of clear phenotypic differences between genotypes.     

Modeling growth and carbon allocation in two reed beds (Phragmites australis) in the Scheldt estuary

Common reed (Phragmites australis) is a prominent species in the upstream part of the eutrophic Scheldt estuary (Belgium, The Netherlands). From 1996 till 1998, seasonal growth dynamics of the species were studied in two monospecific stands subjected to different salinity regimes (seasonal means 1.6 and 13.3 PSU, respectively). We addressed the following questions: how are these reed vegetations affected by meteorological conditions and by the growth site, what are the important growth processes and what is the fate of the annually fixed carbon. A mathematical model was developed and calibrated using the data from the oligohaline site. Subsequent application of the model to the mesohaline stand required adaptation of parameters relating to the partitioning of resources and timing of growth initiation only. At their peak, the aboveground biomass was 587–1678 g DW m⁻² at the 13.3 PSU site and 1116–2179 g DW m⁻² (1.6 PSU); more than 60% of the biomass was located underground. In 1996, biomasses were 2–3 times lower than in the other 2 years, caused by a retarded growth initiation. Probably due to a lower temperature in early 1996, rhizome bud burst occurred more than 1 month later compared to the other years. In addition, growth initiation was several weeks later in the mesohaline site. This appeared mainly responsible for the large difference in maximal aboveground biomass between both stations. Architecture of the plants was also affected, with a higher shoot density (about 50% more shoots), better-developed root system (15% of total belowground biomass compared to 5%) and more, but smaller leaves at the higher salinity site. Notwithstanding large differences in aboveground biomass, annual growth was similar at both stations (154 and 132 mol C m⁻² per year at the oligo- and mesohaline station, respectively). Primary production accounted for about 80% of all growth processes, rhizome remobilization for almost 20%, translocation of mass before sloughing of leaves accounting about 3%. Within a year, some 44% (oligohaline) and 36% (mesohaline) of new assimilates produced by photosynthesis accumulated as dead litter. The other part was respired by the plant itself, either to provide the energy for growth (23%) or maintenance costs (33–41% at the oligo- and mesohaline station, respectively). Calculated annual turnover rates of aboveground biomass, rhizomes and roots were 100, 62 and 73%, respectively.     

Effects of winter harvest on water and sediment chemistry in a stand of reed (Phragmites australis)

An investigation of the effects of repeated winter harvest and removal of dry reed culms on water and sediment chemistry was made in a shallow lake dominated by closed, monospecific reed stands. The oxygen concentration and redox potential in the water, as well as temperature, showed regular diurnal fluctuations inside the reed stands. Ammonium and nitrate + nitrite did not exhibit diurnal fluctuations and differences between a harvested and an unharvested reed area were small. Molybdate reactive phosphorus (MRP) concentration was higher in the unharvested area.Because the winter harvest caused an almost doubling of shoot production compared to the unharvested area, net addition of reed litter (leaves, stubble and culms) to the sediment of the harvested area was similar to that of the unharvested area. It is concluded that removal of reed culms in winter has the largest effect on microclimate in spring, and that the rate of mineralization and reducing intensity in the substrate are not immediately affected. Significantly higher summer standing crop of reed after harvest may have caused lower phosphate concentration in the water column and sediment interstitial water.     

Aggression and fitness differences between plumage morphs in the common buzzard (Buteo buteo)

Genetic plumage polymorphism in birds is increasingly recognizedas a potentially important trait influencing birds’ lifehistories. In the common buzzard Buteo buteo, the 3 color morphsvary in lifetime reproductive success (LRS), but the proximatemechanisms leading to these differences are unknown. We firstconfirmed the stability of the fitness differences found previously,using a greatly extended LRS data set. To find potential causesfor these differences, we experimentally studied variation inaggressive behavior of the morphs, both against an interspecificpredator and intraspecific competitors. The morphs showed substantialvariation in aggressive behavior. Light-colored males were mostaggressive toward an interspecific predator, followed by intermediateand dark males. In females, this pattern was reversed, resultingin sex-related differences of aggression in 2 morphs. When defendingtheir territory against intraspecific competitors, no absolutedifference in aggression was found, but the morphs reacted strongesttoward intruders of a morph similar to their own. This suggeststhat aggression differs both between and within morphs, leadingto a complex pattern on the population level. Coupled with thestrong fitness differences, our results suggest that the geneticbasis of the polymorphism has far-reaching behavioral consequences.     

Small-scale plant species turnover in a limestone grassland: the carousel model and some comments on the niche concept

Abstract. This study reports on small-scale changes in the distribution of plant species in a 2.5 m² plot of grazed, species-rich Veronica spicata - Avenula pratensis grassland on shallow, dry, nutrient-poor soil in the Great Alvar area (Stora Alvaret) of southern Öland, southeastern Sweden. Multivari-ate analysis of 0.001 m² and 0.25 m² quadrats within the plot showed that there is little floristic variation without any trend in the plot. Average species richness varied little throughout the study period from 1986 to 1991 with 1986 averages of 7.0 on 0.001m², 16.3 on 0.01 m², and 26.1 on 0.25 m². On 0.001 m²the highest species number found was 12, on 0.01 m², 27. However, cumulative species richness, i.e. species number in the first year plus new species appearing in later years (averaged over 40 quadrats) increased over the same period, on 0.001 m² from 7.0 in 1986 to 14.9 in 1991, and on 0.01 m² from 16.3 to 24.1. Cumulative frequency, i.e. number of quadrats out of 40 where a species occurred in the first year or/and in later years, increased as well; the number of cumulatively highly frequent (> 80%) species increased from 5 in 1986 to 18 in 1991. Species mobility on the scale of the small quadrats used implies both appearance and disappearance from these quadrats. Using six examples, species mobility is shown to vary individualistically, both in rate and degree. We postulate that in homogeneous, grazed, nutrient- and water-deficient environments many species can reach virtually all microsites within the plot, which we express through the idea of the ‘carousel model’. We also question the usefulness of the niche concept and re-interpret it by stating that all species of this plant community have the same habitat niche, while most of them are short-lived and have the same regeneration niche. The essential variation amongst the species is their individual ability to establish or re-establish by making use of favourable conditions appearing in microsites in an unknown, complex spatio-temporal pattern.     

Cloning and Characterization of a Phragmites australis Phytochelatin Synthase (PaPCS) and Achieving Cd Tolerance in Tall Fescue

The production of phytochelatins (PCs) provides an important means for plants to achieve tolerance to cadmium (Cd) toxicity. A reed gene encoding PC synthase (PaPCS) was isolated and its function tested through its heterologous expression in a strain of yeast sensitive to Cd. Subsequently, the Cd sensitive and high biomass accumulating species tall fescue was transformed either with PaPCS or PaGCS (a glutamyl cysteine synthetase gene of reed) on their own (single transformants), or with both genes together in the same transgene cassette (double transformant). The single and double transformants showed greater Cd tolerance and accumulated more Cd and PC than wild type plants, and their Cd leaf/root ratio content was higher. The ranking in terms of Cd and PC content for the various transgenic lines was double transformants>PaGCS single transformants>PaPCS single transformants>wild type. Thus PaGCS appears to exert a greater influence than PaPCS over PC synthesis and Cd tolerance/accumulation. The double transformant has interesting potential for phytoremediation.     

Paddlefish (Polyodon spathula) in Europe: An aquaculture species and a potential invader

The paddlefish (Polyodon spathula) was first introduced to Europe in 1974, mainly due to its potential for rearing in natural polyculture ponds and large temperate reservoirs. The information on the history of paddlefish aquaculture efforts in Europe is scarce, as well as data on current paddlefish aquaculture status and trends. In addition, there is a lack of data on its presence and potential establishment in the wild, while its invasive potential and associated risks and impacts are largely unknown. In order to evaluate its current status in Europe, we conducted a survey among scientists, aquaculture producers and other stakeholders, and reviewed literature and data on the Internet. Based on the results obtained, we discuss the potential and the challenges in European paddlefish aquaculture development, and analyze paddlefish invasive potential and risks associated with its naturalization. Paddlefish aquaculture is well established only regionally in Europe, but offers relatively high potential for further development in pond farms. Nevertheless, future development will require careful planning, especially regarding market development and improved marketing strategies. While paddlefish likely represents a low‐risk invader, improved control and reporting on trade and intentional and unintentional releases will be required. Given the lack of knowledge on potential impacts following its introduction, due caution seems highly advisable.