Water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes) in the Great Lakes: Playing with fire?

The Laurentian Great Lakes have been successfully invaded by at least 182 nonindigenous species. Here we report on two new species, water hyacinth Eichhornia crassipes and water lettuce Pistia stratiotes, that were found at a number of locations in Lake St. Clair and Detroit River during autumn 2010. Both species are commonly sold in the water garden and aquarium trade in southern Ontario and elsewhere. While it is not clear whether these species are established or can establish in the Great Lakes, the historic assumption that neither of these subtropical to tropical plants pose an invasion risk must be questioned in the light of changing environmental conditions associated with climate warming that may render Great Lakes\u27 habitats more suitable for these species and increase the likelihood of their successful establishment. © 2011 The Author(s)

Prioritising surveillance for alien organisms transported as stowaways on ships travelling to South Africa

The global shipping network facilitates the transportation and introduction of marine and terrestrial organisms to regions where they are not native, and some of these organisms become invasive. South Africa was used as a case study to evaluate the potential for shipping to contribute to the introduction and establishment of marine and terrestrial alien species (i.e. establishment debt) and to assess how this varies across shipping routes and seasons. As a proxy for the number of species introduced (i.e. 'colonisation pressure') shipping movement data were used to determine, for each season, the number of ships that visited South African ports from foreign ports and the number of days travelled between ports. Seasonal marine and terrestrial environmental similarity between South African and foreign ports was then used to estimate the likelihood that introduced species would establish. These data were used to determine the seasonal relative contribution of shipping routes to South Africa's marine and terrestrial establishment debt. Additionally, distribution data were used to identify marine and terrestrial species that are known to be invasive elsewhere and which might be introduced to each South African port through shipping routes that have a high relative contribution to establishment debt. Shipping routes from Asian ports, especially Singapore, have a particularly high relative contribution to South Africa's establishment debt, while among South African ports, Durban has the highest risk of being invaded. There was seasonal variation in the shipping routes that have a high relative contribution to the establishment debt of the South African ports. The presented method provides a simple way to prioritise surveillance effort and our results indicate that, for South Africa, port-specific prevention strategies should be developed, a large portion of the available resources should be allocated to Durban, and seasonal variations and their consequences for prevention strategies should be explored further. (Résumé d'auteur

Identifying potential emerging invasive non-native species from the freshwater pet trade

1. An increasingly globalised world has facilitated the movement of non-native species (NNS) via the poorly regulated international pet trade. While focus is increasingly being placed on preventative action to combat invasive NNS—often cheaper and less difficult than the management of established populations—successful prevention requires controlling potential pathways and obtaining baseline knowledge of species' availability. 2. Here we performed an in-depth analysis of the freshwater pet trade as one major vector of NNS, compiling its species inventory and deriving threats of NNS release and establishment in the wild. With Germany as our study region, we surveyed pet stores, websites and the country's largest online classified portal, eBay Kleinanzeigen, recording the taxa encountered. For each species, we determined the likelihood of release based on availability and price (cheaper and/or more readily available species have been shown to be of greater risk), and the likelihood of establishment based on ecological niche breadth and niche overlap with environmental conditions in Germany. 3. The survey revealed 669 species, of which 651 were non-native to Germany. Looking at release likelihood, more readily available species in pet stores and on websites proved to be cheaper. For websites, there was a significant effect of occurrence status (i.e. released, not released, native) on price, with released and native species being significantly cheaper. Species previously released in Germany and elsewhere demonstrated greater niche breadths and greater niche overlaps between their source regions and Germany; and for species released in Germany, there was a significantly positive relationship between the magnitude of niche overlap and the number of documented occurrences. 4. Finally, we combined our release and establishment likelihood findings under ‘Release Risk’ metrics to highlight the species most worthy of prioritisation. We propose these metrics as proactive methods for screening species in the trade, which can inform future policy direction and intervention

Current temperatures limit the potential impact of a commonly traded predatory gastropod

The pet trade has facilitated the spread of invasive alien species (IAS) globally, with negative consequences for biodiversity. The prediction of impacts is a major goal for invasion ecologists, and is especially crucial in an industry often lacking knowledge about traded species. We focused on the predatory gastropod Anentome helena, a species originating in south-east Asia and traded around the world, but with taxonomic uncertainty. We first set out to determine where our study organism fell within the A. “helena” species complex, known to comprise at least four cryptic species, before assessing the effect of temperature on the number of prey, the pulmonate snail Physella acuta, killed per predator via functional response experiments at two temperatures. We used 22 °C as a recommended temperature for housing the species in captivity, and 18 °C as a representative summer lake temperature in temperate climates of Europe. We also assessed the role of predator group size (1×, 2×, 3×) on predation (total consumption and average per capita consumption) at the experimental temperatures with fixed densities of prey, as well as the effect of these temperatures on prey activity. Our organisms belonged to a cryptic species originating from Thailand (Anentome sp. A), matching the findings of aquarium trade samples in other continents. In the functional response experiments, we found maximum feeding rate to be significantly reduced at the lower temperature. A similar result ensued from group feeding, with total consumption significantly reduced and the reduction in average per capita consumption approaching significance at the lower temperature. There was no significant effect of group size on the average per capita consumption in the group trial, indicating neutral conspecific interactions. No significant effect of temperature on the activity of the prey species was found, suggesting decreased consumption was mainly driven by predator, rather than prey. These results suggest limited A. helena impacts in the short-term, but increasing temperatures with climate change may facilitate greater consequences from releases. We suggest future studies assess other potential predatory impacts and survival across relevant abiotic conditions, and encourage the use of similar methods to assess the impacts of other commonly traded species

More than we bargained for: Zebra mussels transported amongst European native freshwater snails

The international pet trade is a major driver of non-native species spread, including species both sold in the trade, and organisms incidentally transported alongside. Here, we document the discovery of invasive zebra mussels, Dreissena polymorpha, in Germany, transported alongside a commonly traded garden pond snail and European native, Viviparus viviparus, ordered from a German pet website. We highlight that the trade poses yet another way in which zebra mussels and other invasive species can expand their invaded range into novel ecosystems. We call for stricter biosecurity enforcement towards sellers, and encourage raising awareness amongst customers to inhibit the further spread of invasive species through the pet trade

Invasion Pathway of the Ctenophore Mnemiopsis leidyi in the Mediterranean Sea

Gelatinous zooplankton outbreaks have increased globally owing to a number of human-mediated factors, including food web alterations and species introductions. The invasive ctenophore Mnemiopsis leidyi entered the Black Sea in the early 1980s. The invasion was followed by the Azov, Caspian, Baltic and North Seas, and, most recently, the Mediterranean Sea. Previous studies identified two distinct invasion pathways of M. leidyi from its native range in the western Atlantic Ocean to Eurasia. However, the source of newly established populations in the Mediterranean Sea remains unclear. Here we build upon our previous study and investigate sequence variation in both mitochondrial (Cytochrome c Oxidase subunit I) and nuclear (Internal Transcribed Spacer) markers in M. leidyi, encompassing five native and 11 introduced populations, including four from the Mediterranean Sea. Extant genetic diversity in Mediterranean populations (n = 8, Na = 10) preclude the occurrence of a severe genetic bottleneck or founder effects in the initial colonizing population. Our mitochondrial and nuclear marker surveys revealed two possible pathways of introduction into Mediterranean Sea. In total, 17 haplotypes and 18 alleles were recovered from all surveyed populations. Haplotype and allelic diversity of Mediterranean populations were comparable to populations from which they were likely drawn. The distribution of genetic diversity and pattern of genetic differentiation suggest initial colonization of the Mediterranean from the Black-Azov Seas (pairwise FST = 0.001–0.028). However, some haplotypes and alleles from the Mediterranean Sea were not detected from the well-sampled Black Sea, although they were found in Gulf of Mexico populations that were also genetically similar to those in the Mediterranean Sea (pairwise FST = 0.010–0.032), raising the possibility of multiple invasion sources. Multiple introductions from a combination of Black Sea and native region sources could be facilitated by intense local and transcontinental shipping activity, respectively

ALAD and APOE polymorphisms are associated with lead and mercury levels in Italian pregnant women and their newborns with adequate nutritional status of zinc and selenium

The impacts of single-nucleotide polymorphisms (SNPs) in ALAD and VDR genes on Pb health effects and/or kinetics are inconclusive at low exposure levels, while studies including APOE SNPs are rare. In this study, we examined the associations of ALAD, VDR and APOE SNPs with exposure biomarkers of Pb and other trace elements (TEs) in Italian pregnant women (N = 873, aged 18–44 years) and their newborns (N = 619) with low-level mixed-element exposure through diet, the environment or endogenously. DNA from maternal peripheral venous blood (mB), sampled during the second and third trimesters, was genotyped for ALAD (rs1800435, rs1805313, rs1139488, rs818708), VDR (rs2228570, rs1544410, rs7975232, rs731236) and APOE (rs429358, rs7421) using TaqMan SNP assays. Personal and lifestyle data and TE levels (mB, maternal plasma, hair and mixed umbilical cord blood [CB]) from the PHIME project were used. Multiple linear regression models, controlling for confounding variables, were performed to test the associations between SNPs and TEs. The geometric means of mB-Pb, mB-Hg, mB-As and mB-Cd (11.0 ng/g, 2.16 ng/g, 1.38 ng/g and 0.31 ng/g, respectively) indicated low exposure levels, whereas maternal plasma Zn and Se (0.72 μg/mL and 78.6 ng/g, respectively) indicated adequate micronutritional status. Variant alleles of ALAD rs1800435 and rs1805313 were negatively associated with mB-Pb levels, whereas a positive association was observed for rs1139488. None of the VDR SNPs or their haplotypes had any association with Pb levels. Regarding APOE, the ϵ4 allele was associated with lower mB-Hg and CB-Hg, while a positive association was found with the ϵ2 allele and CB-Pb when the model included only newborn girls. The observed associations indicate possible modification effects of ALAD and APOE SNPs on Pb or Hg kinetics in women and their newborns with low exposure to non-essential TEs, as well as an adequate nutritional status of Zn and Se

Diversity and patterns of marine non‐native species in the archipelagos of Macaronesia

Aims The present study is the first attempt to grasp the scale and richness of marine biological invasions in Macaronesia. We pioneered a comprehensive non-native species (NNS), inventory in the region to determine their diversity patterns and native distribution origins. NNS were defined here as the result of both introductions and range expansions. We also used statistical modelling to examine relationships among NNS richness, anthropogenic activities, demographic and geographical variables across Macaronesia. Location Macaronesia. Methods A comprehensive literature search was conducted for marine NNS records in Macaronesia, registering the first record's location and year from 1884 to 2020. We used univariate and multivariate analyses to evaluate differences and similarities in community composition. By applying a Generalized Linear Model (GLM), we tested hypotheses regarding NNS richness as a function of anthropogenic activities, demographic and geographical variables. Results A total of 144 marine non-native species (NNS) were recorded for the whole of Macaronesia. The highest NNS richness was registered in the Canary Islands (76 NNS), followed by the Azores (66 NNS), Madeira (59 NNS) and finally Cabo Verde (18 NNS). Some differences amongst archipelagos were observed, such as the high number of non-native macroalgae in the Azores, fishes in the Canary Islands and tunicates in Cabo Verde. Overall, macroalgae, tunicates and bryozoans were the predominant taxonomic groups in the Macaronesian archipelagos. Madeira and Canary Islands were the archipelagos with more similarity in marine NNS, and Cabo Verde the most divergent. Finally, GLM suggested that non-native richness patterns across Macaronesia were dependent on the considered archipelago and strongly affected by (1) minimum distance to the mainland, (2) the total number of ports and marinas and (3) total marinas area (km2). Conclusions The model results and NNS listing in the present study will likely raise the awareness and response regarding marine NNS in the whole Macaronesia region, serving as a baseline for future research as well as implementing and enforcing regulations related to the introduction of marine NNS in oceanic islands

Relationship between propagule pressure and colonization pressure in invasion ecology: a test with ships' ballast

Increasing empirical evidence indicates the number of released individuals (i.e. propagule pressure) and number of released species (i.e. colonization pressure) are key determinants of the number of species that successfully invade new habitats. In view of these relationships, and the possibility that ships transport whole communities of organisms, we collected 333 ballast water and sediment samples to investigate the relationship between propagule and colonization pressure for a variety of diverse taxonomic groups (diatoms, dinoflagellates and invertebrates). We also reviewed the scientific literature to compare the number of species transported by ships to those reported in nature. Here, we show that even though ships transport nearly entire local communities, a strong relationship between propagule and colonization pressure exists only for dinoflagellates. Our study provides evidence that colonization pressure of invertebrates and diatoms may fluctuate widely irrespective of propagule pressure. We suggest that the lack of correspondence is explained by reduced uptake of invertebrates into the transport vector and the sensitivity of invertebrates and diatoms to selective pressures during transportation. Selection during transportation is initially evident through decreases in propagule pressure, followed by decreased colonization pressure in the most sensitive taxa

Biological invasion costs reveal insufficient proactive management worldwide

Funding Information: The authors thank the French National Research Agency (ANR-14-CE02-0021) and the BNP-Paribas Foundation Climate Initiative for funding the InvaCost project and the work on InvaCost database development. The present work was conducted in the frame of InvaCost workshop carried in November 2019 (Paris, France) and funded by the AXA Research Fund Chair of Invasion Biology and is part of the AlienScenario project funded by BiodivERsA and Belmont-Forum call 2018 on biodiversity scenarios. RNC was funded through a Leverhulme Early Career Fellowship (ECF-2021-001) from the Leverhulme Trust and a Humboldt Postdoctoral Fellowship from the Alexander von Humboldt Foundation. DAA is funded by the Kuwait Foundation for the Advancement of Sciences (KFAS) (PR1914SM-01) and the Gulf University for Science and Technology (GUST) internal seed funds (187092 & 234597). CA was funded by the French National Centre for Scientific Research (CNRS). TWB acknowledges funding from the European Union's Horizon 2020 research and innovation programme Marie Skodowska-Curie fellowship (Grant No. 747120). FE was funded through the 2017?2018 Belmont Forum and BiodivERsA joint call for research proposals, under the BiodivScen ERA-Net COFUND programme, and with the funding organisation Austrian Science Foundation FWF (grant I 4011-B32). NK is funded by the basic project of Sukachev Institute of Forest SB RAS, Russia (Project No. 0287-2021-0011; data mining) and the Russian Science Foundation (project No. 21-16-00050; data analysis).Peer reviewedPublisher PD