Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Cuthbert, R. N., Pattison, Z., Taylor, N. G., Verbrugge, L., Diagne, C., Ahmed, D. A., Leroy, B., Angulo, E., Briski, E., Capinha, C., Catford, J. A., Dalu, T., Essl, F., Gozlan, R. E., Haubrock, P. J., Kourantidou, M., Kramer, A. M., Renault, D., Wasserman, R. J., & Courchamp, F. Global economic costs of aquatic invasive alien species. Science of the Total Environment, 775, (2021): 145238, https://doi.org/10.1016/j.scitotenv.2021.145238.

Description: Much research effort has been invested in understanding ecological impacts of invasive alien species (IAS) across ecosystems and taxonomic groups, but empirical studies about economic effects lack synthesis. Using a comprehensive global database, we determine patterns and trends in economic costs of aquatic IAS by examining: (i) the distribution of these costs across taxa, geographic regions and cost types; (ii) the temporal dynamics of global costs; and (iii) knowledge gaps, especially compared to terrestrial IAS. Based on the costs recorded from the existing literature, the global cost of aquatic IAS conservatively summed to US$345 billion, with the majority attributed to invertebrates (62%), followed by vertebrates (28%), then plants (6%). The largest costs were reported in North America (48%) and Asia (13%), and were principally a result of resource damages (74%); only 6% of recorded costs were from management. The magnitude and number of reported costs were highest in the United States of America and for semi-aquatic taxa. Many countries and known aquatic alien species had no reported costs, especially in Africa and Asia. Accordingly, a network analysis revealed limited connectivity among countries, indicating disparate cost reporting. Aquatic IAS costs have increased in recent decades by several orders of magnitude, reaching at least US$23 billion in 2020. Costs are likely considerably underrepresented compared to terrestrial IAS; only 5% of reported costs were from aquatic species, despite 26% of known invaders being aquatic. Additionally, only 1% of aquatic invasion costs were from marine species. Costs of aquatic IAS are thus substantial, but likely underreported. Costs have increased over time and are expected to continue rising with future invasions. We urge increased and improved cost reporting by managers, practitioners and researchers to reduce knowledge gaps. Few costs are proactive investments; increased management spending is urgently needed to prevent and limit current and future aquatic IAS damages.

Description: The authors acknowledge the French National Research Agency (ANR-14-CE02-0021) and the BNP-Paribas Foundation Climate Initiative for funding the InvaCost project that allowed the construction of the InvaCost database. The present work was conducted following a workshop funded by the AXA Research Fund Chair of Invasion Biology and is part of the AlienScenarios project funded by BiodivERsA and Belmont-Forum call 2018 on biodiversity scenarios. RNC is funded through a Humboldt Research 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 fund (187092). CD was funded by the BiodivERsA-Belmont Forum Project AlienScenarios (BMBF/PT DLR 01LC1807C). EA was funded by the AXA Research Fund Chair of Invasion Biology of University Paris Saclay. CC was supported by Portuguese National Funds through Fundação para a Ciência e a Tecnologia (CEECIND/02037/2017; UIDB/00295/2020 and UIDP/00295/2020). TD acknowledges funding from National Research Foundation (NRF_ZA) (Grant Number: 117700). FE appreciates funding by the Austrian Science Foundation (FWF project no I 4011-B32). AMK was supported by the NSF Macrosystems Biology program under grant 1834548. DR thanks InEE-CNRS who supports the French national network Biological Invasions (Groupement de Recherche InvaBio, 2014–2022).

Description: A comprehensive dataset of non-native species (NNS) was assembled by combining the SInAS database of alien species occurrences (Seebens, 2021) with several other publicly available databases and NNS lists to examine NNS diversity globally (Bailey et al., 2020; Campbell et al., 2016; Carlton & Eldredge, 2009; Casties et al., 2016; Eldredge & Carlton, 2015; Hewitt et al., 2002, 2004; Lambert, 2002; Meyer, 2000; NEMESIS, 2017, 2020; Paulay et al., 2002; Richardson et al., 2020; Schwindt et al., 2020; Sturtevant et al., 2019; U.S. Geological Survey, 2017; Wonham & Carlton, 2005) to examine NNS diversity globally. The SInAS_AlienSpeciesDB_2.4.1 file was used as the base file for our dataset. Species without assignment of invaded country/region were removed from the dataset. Then, species assigned only as CASUAL and ABSENT in the columns degreeOfEstablishment (N) and occurrenceStatus (L), respectively, were also removed due to their undetermined non-native establishment status in those particular regions (Groom et al., 2019). Following, species from other publicly available databases and NNS lists that had not been listed for particular region/s in the SInAS database were added to the file. The species that were both native and NNS within a continent were retained in the dataset. Accordingly, the dataset consisted 36 822 species established outside of their native regions, out of which 36 326 came from Seebens (2021) and 496 species from other databases and NNS lists. Binominal scientific names, phylum, class, and family levels were assigned to each species based on the SInAS_AlienSpeciesDB_2.4.1_FullTaxaList file that was originally determined following Global Biodiversity Information Facility (GBIF). When a species was not automatically assigned to binominal scientific name and/or taxonomic level, an additional manual search of GBIF, World Register of Marine Species (WoRMS) and a general internet search engine was conducted in June and July 2022, and September 2023. Also, to examine NNS diversity among different habitats (i.e., terrestrial, freshwater, and marine), we assigned one or more habitats for each species based on the Step2_StandardTerms_GRIIS file; habitat data in the Step2_StandardTerms_GRIIS file originated from the Global Register of Introduced and Invasive Species (GRIIS). Again, if habitat(s) was(were) not automatically assigned to a species, an additional manual search of WoRMS and a general internet search engine was conducted from July to September 2022. We emphasize that due to the great number of species in our dataset and changing information availability over time, there is a possibility that we did not list all potential habitats for all species. Brackish habitats were defined as marine based on the Venice System (1958). Regions were assigned based on the geographic continental definitions (i.e., North America, South America, Europe, Africa, Asia, and Australia), with Pacific islands as a separate region due to their unclear/undefined continental affiliations (National Geographic Society, 2022). Finally, global estimated biodiversity (i.e., numbers of species per taxonomic group) of each particular phylum, class, and family was obtained from the GBIF in October 2022 (GBIF, 2022).