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4 Examples of introduced species recognized at the time of their description as non- native or possibly non-native Isopoda (isopods)
Source publication
A critical component of — and a limitation on — interpreting community structure is a detailed understanding of the ecological
and evolutionary history of the assemblage of species in question. There are thus compelling reasons to under stand, and seek
to measure, how communities have changed over both evolution ary (geological) and ecological (his...
Citations
... There is a lack of standardised longer-term community data from the invaded environments, that can help us interpret how community assembly and ecosystem functions change over time in response to multiple invasions (Carlton, 2009). Impacts of marine NIS are known to vary from species-to-species and place-to-place, but most marine invasions have likely not reached equilibrium and the size of the invaded range for NIS is strongly associated with 'time since arrival' (Byers et al., 2015;Galil, 2021). ...
... Other common challenges in bioinvasion ecology that can impede comparative functional traits analyses are (i) precise taxonomic identification or taxonomic bias (Ojaveer et al., 2021) and (ii) correctly assigning biogeographical status for all component species in a community (Carlton, 1996(Carlton, , 2009Marchini & Cardeccia, 2017). ...
Aim
Retrospective (pre‐ vs. post‐invasion) and cross‐sectional comparisons of ecosystems exposed to high and low bioinvasion pressure, provide an alternative approach to evaluate shifts in biological communities associated with non‐indigenous species (NIS) introductions. In this study, we aimed to examine general patterns of change in community composition, structure and function in six well‐studied and globally distributed marine ecosystems that had documented histories of biological invasions.
Location
Global.
Methods
By considering a range of regional datasets and different sampling approaches, we evaluated trends within and among ecosystems by comparing paired measures of community and functional structure in either space or time.
Results
Our analyses revealed different patterns of structural and functional change at ecosystem scales, but direct comparisons across regions were hindered by confounding effects of study designs and other drivers of change. The most prominent shifts in community composition were observed in the retrospective studies, characterised by the greatest relative contribution of NIS. No uniform pattern of change in functional metrics was observed across study regions. However, functional evenness and dispersion showed a tendency to increase in systems under higher invasion pressure, refuting the hypothesis of selective accumulation of specific traits and functional homogenisation within ecosystems exposed to high invasion pressure.
Main Conclusions
Accumulation of NIS within broader communities can be a subtle process, with inherent spatial and temporal variability. Nonetheless, not only do species' proportional contributions to communities change over time in areas subjected to high bioinvasion pressure, but trait profiles can incrementally shift, which alters the original ecology of an area. Planned, long‐term studies that incorporate a range of measures of environmental drivers and ecosystem response are crucial for better understanding of cumulative, community‐level and ecosystem‐scale change associated with biological invasions.
... Clavelina oblonga is an ascidian originally described from Bermuda, whose native range is considered the tropical western Atlantic Ocean (Rocha et al. 2012). The species has a long invasion history, at least since 1929 in the Mediterranean, which has led to confusion regarding its biogeographical status (Carlton 2009). Here we report for the first time on the occurrence of C. oblonga in Slovenia (45.48778°N; 13.58532°E) and Tunisia (34.30650°N; 10.15590°E) ( Figure 9A, B). ...
To enrich spatio-temporal information on the distribution of alien, cryptogenic, and
neonative species in the Mediterranean and the Black Sea, a collective effort by 173
marine scientists was made to provide unpublished records and make them open
access to the scientific community. Through this effort, we collected and harmonized
a dataset of 12,649 records. It includes 247 taxa, of which 217 are Animalia, 25 Plantae
and 5 Chromista, from 23 countries surrounding the Mediterranean and the Black
Sea. Chordata was the most abundant taxonomic group, followed by Arthropoda,
Mollusca, and Annelida. In terms of species records, Siganus luridus, Siganus rivulatus,
Saurida lessepsianus, Pterois miles, Upeneus moluccensis, Charybdis (Archias)
longicollis, and Caulerpa cylindracea were the most numerous. The temporal
distribution of the records ranges from 1973 to 2022, with 44% of the records in
2020–2021. Lethrinus borbonicus is reported for the first time in the Mediterranean
Sea, while Pomatoschistus quagga, Caulerpa cylindracea, Grateloupia turuturu,
and Misophria pallida are first records for the Black Sea; Kapraunia schneideri is
recorded for the second time in the Mediterranean and for the first time in Israel;
Prionospio depauperata and Pseudonereis anomala are reported for the first time
from the Sea of Marmara. Many first country records are also included, namely:
Amathia verticillata (Montenegro), Ampithoe valida (Italy), Antithamnion
amphigeneum (Greece), Clavelina oblonga (Tunisia and Slovenia), Dendostrea cf.
folium (Syria), Epinephelus fasciatus (Tunisia), Ganonema farinosum (Montenegro),
Macrorhynchia philippina (Tunisia), Marenzelleria neglecta (Romania), Paratapes
textilis (Tunisia), and Botrylloides diegensis (Tunisia).
... B. diegensis is commonly seen in the intertidal zone throughout Aotearoa New Zealand's coasts and is thought to have originated from the Western or Southern Pacific and was potentially introduced to the Atlantic and Northern Pacific, whereas B. leachii is stated to have Mediterranean origins and is recorded to be non-indigenous to the Indo-Pacific. (Carlton 2009;Shenkar and Swalla 2011;Page and Kelly 2013;Page et al. 2014;Viard et al. 2019). B. diegensis is globally invasive; therefore, its detection is important for the protection of marine diversity (Viard et al. 2019). ...
... The onset of shipping in ancient times extended the range of human penetration to new areas that had not been accessible earlier, making it possible to transfer many species further and further by means of unintentional and intentional 'methods' (vectors) functioning on the land by that time. Moreover, it triggered new vectors of dispersal enabling also aquatic species, like those attached to ship bottoms, and a wide variety of taxa inside ships in ballast sand, with ballast rocks (or other solid ballast), and in more recent times, in ballast water, to spread (Carlton, 2003;Leppäkoski et al., 1957;Ouren, 1978;Ridley, 1930;Wolff, 2005;Carlton, 2009;Galil et al., 2018;Ojaveer et al., 2018). ...
... Since the 16th century, when shipping gained global dimension, these vectors became an important factor deciding on the dispersal of many aquatic and terrestrial species being able to colonise coastal zones around the world. Coastlines and continental shelves serve as dispersal corridors of species referred to as 'corridor' species (Carlton, 2009). Therefore widespread species have almost always been interpreted as natural and long-standing distributions, however, the aboriginal distributions of many widespread 'corridor' species prior to the onset of global shipping are basically unknown (Carlton, 2009) and, according to the opinion of Galil et al. (2018) that 'shipping precedes science', the presumptive natural distributions of many species should be brought into question (Carlton, 2003). ...
... Coastlines and continental shelves serve as dispersal corridors of species referred to as 'corridor' species (Carlton, 2009). Therefore widespread species have almost always been interpreted as natural and long-standing distributions, however, the aboriginal distributions of many widespread 'corridor' species prior to the onset of global shipping are basically unknown (Carlton, 2009) and, according to the opinion of Galil et al. (2018) that 'shipping precedes science', the presumptive natural distributions of many species should be brought into question (Carlton, 2003). As Carlton (1999) suggested, a minimum of three to five species per year may have been transported by ships around the world from the 16th to the 18th centuries. ...
The occurrence of Chara connivens (Charophyta, Characeae) and its status in the Baltic Sea may raise controversies regarding its origin and historical dispersal pathways in the area. This study critically revises the protection status of C. connivens in the countries around the Baltic Sea, as well as its status on the red lists of endangered plant species (including the HELCOM Red List). The first reports on the presence of C. connivens in the Baltic Sea area were published in the aftermath of Carl Baenitz’s talks given in the early 1870s. Already then, the scientific community was well aware of the fact that C. connivens had been introduced as a ballast plant to the known Baltic areas of occurrence – the first known record of the species is of 1829. Since Poland is the only country where C. connivens is protected, the historical and contemporary distribution of this charophyte in the Polish coastal waters is presented against the background of the available historical and recent records of the species in the Baltic Sea. Recent reports from the second half of the 20th century and the beginning of the 21st century have confirmed a fairly common occurrence of C. connivens in Estonia, Sweden and Poland. This species still occurs on the German coast and has also been reported from Finland (the Åland archipelago). In recent
decades, however, the species was considered rare in the Baltic Sea area. In Poland, C. connivens was even classified as extinct, despite earlier data on its occurrence in the Vistula Lagoon in the 1970s, where it was rediscovered in 2011. It was also found in the Szczecin Lagoon a year later. Both localities well suit Luther’s pattern of C. connivens occurrence in areas with intensive shipping and ballast discharge operations in historical times. Based on this in-depth revision of historical and current distribution, it is postulated that C. connivens, as non-indigenous, should not be red-listed in the Baltic Sea area, following the example of Finland. Moreover, its legal status in Poland of a strictly protected species should be reconsidered.
... Additionally, the conspecificity of populations of other widespread introduced ascidians has been supported by molecular evidence like Styela plicata (Lesueur, 1823) (Barros et al. 2009;Pineda et al. 2011) and Didemnum vexillum Kott, 2002(Stefaniak et al. 2009Casso et al. 2019). Often, widely distributed species translocated to several areas of the world receive local names, and thus fail to be recognized as introduced, constituting instances of the so-called pseudo-indigenous species (Carlton 2009). Upon closer morphological and genetic examination, these species can be shown to correspond to taxa described elsewhere (e.g., Ordóñez et al. 2016;Viard et al. 2019). ...
A colonial ascidian of the genus Distaplia caused a mass mortality of the pen shell Atrina maura (Sowerby, 1835) during June 2016 in the southwest of the Gulf of California (Mexico), with a significant socio-economic cost. Tentatively identified in previous works as Distaplia cf. stylifera, a precise taxonomic determination was still lacking. In the present work, based on a detailed morphological study, it is confirmed that this aggressive species is Distaplia stylifera (Kowalevsky, 1874). Originally described from the Red Sea, the species currently has a wide circumtropical distribution (with the exception of the Eastern Pacific to date) and is reported as introduced in parts of its range. The present account thus represents an important range extension of this species. However, when revising the original description and later observations, the reported variability of several characters makes it likely that the binomen is in fact a complex of species, as is common in other ascidians with wide distributions. A complete morphological and genetic study including populations from the entire range of distribution would be necessary to settle the status of D. stylifera . Taxonomic uncertainties hinder a correct interpretation of biogeographical patterns and inference on the origin of the studied population. Nevertheless, the known introduction potential of the species, coupled with an explosive growth in an anthropized environment, and the lack of any previous reports in the Eastern Pacific, strongly suggest that the investigated population represents yet another instance of ascidian introduction. From the point of view of management, its invasive behavior is cause for great concern and warrants mitigation measures.
... Similarly, for many IAS, basic aspects of their biology and ecology in both native and invaded ranges as well as their taxonomy are poorly studied, which can often hinder proper targeting of management efforts (e.g., Didemnum vexillum (Kott, 2002), Fletcher and Forrest, 2011;Zhan et al., 2015). For cryptogenic species, clarifying their biogeographic status or taxonomic identity is of paramount importance, as the lack of knowledge can contribute to underestimating the number of non-native species in a given area and, consequently, their inclusion in IAS lists (Carlton, 2009). ...
As the number of introduced species keeps increasing unabatedly, identifying and prioritising current and potential Invasive Alien Species (IAS) has become essential to manage them. Horizon Scanning (HS), defined as an exploration of
potential threats, is considered a fundamental component of IAS management. By combining scientific knowledge on
taxa with expert opinion, we identified the most relevant aquatic IAS in the Iberian Peninsula, i.e., those with the
greatest geographic extent (or probability of introduction), severe ecological, economic and human health impacts,
greatest difficulty and acceptability of management. We highlighted the 126 most relevant IAS already present in Iberian inland waters (i.e., Concern list) and 89 with a high probability of being introduced in the near future (i.e., Alert
list), of which 24 and 10 IAS, respectively, were considered as a management priority after receiving the highest scores
in the expert assessment (i.e., top-ranked IAS). In both lists, aquatic IAS belonging to the four thematic groups (plants,
freshwater invertebrates, estuarine invertebrates, and vertebrates) were identified as having been introduced through
various pathways from different regions of the world and classified according to their main functional feeding groups.
Also, the latest update of the list of IAS of Union concern pursuant to Regulation (EU) No 1143/2014 includes only 12
top-ranked IAS identified for the Iberian Peninsula, while the national lists incorporate the vast majority of them. This
fact underlines the great importance of taxa prioritisation exercises at biogeographical scales as a step prior to risk analyses and their inclusion in national lists. This HS provides a robust assessment and a cost-effective strategy for decisionmakers and stakeholders to prioritise the use of limited resources for IAS prevention and management. Although applied at a transnational level in a European biodiversity hotspot, this approach is designed for potential application
at any geographical or administrative scale, including the continental one.
... Over the past several centuries, scientists have documented an increasing flow of species across oceans that is in association with human activities (Carlton et al. 2003;Carlton 2009). Unfortunately, our lack of information about the basic biology and ecology of certain non-native species limits our understanding of their invasion process and status. ...
... Such is the case of invertebrate organisms with no historical reports as threats and a little to no commercial value (Zabin et al. 2007). Sources of underestimation of non-native species richness within an area are diverse and include taxonomic, biogeographic, and sampling errors (Carlton 2009). Taxonomic biases are unfortunately common in invasion ecology as researchers seem to target certain taxa, thereby focusing only on certain species within those taxa. ...
... This leads to an over-representation of some nonnative species in the literature, to the detriment of others (Bailey et al. 2020;Watkins et al. 2021). Likewise, taxonomic errors abound as non-native species can be mistakenly considered as native due to re-descriptions or misidentifications after introduction (defined as pseudoindigenous species; sensu Carlton 2009). ...
The attention towards non-native sea anemone introductions has been steadily increasing as multiple species are reported from new locations each year. However, a lack of monitoring efforts and difficulties associated with the detection and identification of these species may result in overlooking introductions in certain areas. In the southern hemisphere, one of these non-native species is Metridium senile, whose current taxonomic and invasion status in Argentina is unclear. Here, we pooled scientific and community records to shed light on the past, current and future invasion scenario of this species. First, we clarified the taxonomic and invasion status of suspected M. senile populations from Argentina by revising available morphological descriptions and attributes associated with non-native species. Then, we inferred and described the potential dispersal pattern in Argentina from the late 1890s to present day. Finally, we provided a forecast of the species potential distribution range in the Southwestern Atlantic Ocean, along the coast and in off-shore areas. Enough evidence suggests that M. senile is a non-native species that has successfully established in Argentina. This species has been mistakenly considered as native for decades due to taxonomic errors and historical and geographical gaps (i.e., pseudoindigenous species). Its current distribution range in Argentina covers over 2000 km of coastline with a southward expansion in recent years. Moreover, according to our forecasted potential distribution, this species can spread further and reach novel areas in coastal and off-shore locations. As M. senile combines multiple traits of a successful invader, monitoring efforts should be implemented to early detect or prevent its establishment in areas recently colonized or at risk.
... Clavelina oblonga is an ascidian originally described from Bermuda, whose native range is considered the tropical western Atlantic Ocean (Rocha et al. 2012). The species has a long invasion history, at least since 1929 in the Mediterranean, which has led to confusion regarding its biogeographical status (Carlton 2009). Here we report for the first time on the occurrence of C. oblonga in Slovenia (45.48778°N; 13.58532°E) and Tunisia (34.30650°N; 10.15590°E) ( Figure 9A, B). ...
To enrich spatio-temporal information on the distribution of alien, cryptogenic, and neonative species in the Mediterranean and the Black Sea, a collective effort by 173 marine scientists was made to provide unpublished records and make them open access to the scientific community. Through this effort, we collected and harmonized a dataset of 12,649 records. It includes 247 taxa, of which 217 are Animalia, 25 Plantae and 5 Chromista, from 23 countries surrounding the Mediterranean and the Black Sea. Chordata was the most abundant taxonomic group, followed by Arthropoda, Mollusca, and Annelida. In terms of species records, Siganus luridus, Siganus rivulatus, Saurida lessepsianus, Pterois miles, Upeneus moluccensis, Charybdis (Archias) longicollis, and Caulerpa cylindracea were the most numerous. The temporal distribution of the records ranges from 1973 to 2022, with 44% of the records in 2020-2021. Lethrinus borbonicus is reported for the first time in the Mediterranean Sea, while Pomatoschistus quagga, Caulerpa cylindracea, Grateloupia turuturu, and Misophria pallida are first records for the Black Sea; Kapraunia schneideri is recorded for the second time in the Mediterranean and for the first time in Israel; Prionospio depauperata and Pseudonereis anomala are reported for the first time from the Sea of Marmara. Many first country records are also included, namely: Amathia verticillata (Montenegro), Ampithoe valida (Italy), Antithamnion amphigeneum (Greece), Clavelina oblonga (Tunisia and Slovenia), Dendostrea cf. folium (Syria), Epinephelus fasciatus (Tunisia), Ganonema farinosum (Montenegro), Macrorhynchia philippina (Tunisia), Marenzelleria neglecta (Romania), Paratapes textilis (Tunisia), and Botrylloides diegensis (Tunisia).
... This is the first record of this widespread tramp species from the African continent. We also draw attention to the fact that the species may well have been present on many of the islands in the south-western Indian Ocean for as long as 150 years, hiding in the guise of pseudoindigenous taxa (Carlton 2009) -something that remains to be investigated using molecular techniques. ...
... Given the ease with which small snails can be translocated and the extent to which G. servilis has colonised islands in S-E Asia and the western Pacific, we consider it probable that the same has happened on the islands of the western Indian Ocean and on its continental margin. Here, as in the western Pacific, the introduced populations have frequently been redescribed as supposedly indigenous species -the pseudoindigenes of Carlton (2009). Fischer-Piette et al. (1994 have already relegated G. tripunctum and G. madagascariensis to the synonymy of G. seignaciana, and Gerlach (2006) considered this in turn to be the same as G. microscopica (though he incorrectly credited the latter name to Nevill, 1878 and thus afforded it priority). ...
... The study of these species is crucial for maintaining biodiversity and ecosystem functions in a given area (Byers et al. 2002). NIS can dramatically alter the diversity and productivity of ecosystems (Carlton 2009) and the biotic relationships among native species (Byers et al. 2002), potentially leading to their local extinction (Haugom et al. 2002). Furthermore, the alteration of an ecosystem by NIS can subsequently facilitate the introduction of additional new exotic species (Simberloff and Holle 1999;Floerl et al. 2004;Wonham and Lewis 2009). ...
