The fate of an immigrant: Ensis directus in the eastern German Bight

Dannheim, Jennifer; Rumohr, Heye

doi:10.1007/s10152-011-0271-2

Cited by 26 publications

(20 citation statements)

References 36 publications

(52 reference statements)

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“…However, differences were observed on modelled niches and spatial projections. Limits of the ecological niches modelled with both ENMs (minimum and maximum thermal tolerances and bathymetric preference) do not differ greatly and are consistent with the ecological knowledge of the clam (Cardoso et al 2006(Cardoso et al , 2009Dannheim and Rumohr 2012;Dauvin et al 2007;Dekker and Beukema 2012;Freudendahl et al 2010;Ghertsos et al 2000;Palmer 2004;Vierna et al 2012;Beukema and Dekker 1995). The main differences between NPPEN and MAXENT results are generated by the shape of the ecological niche (fringe of the niche steeper with MAXENT than with NPPEN).…”

Section: Projected Equatorward Expansion Of Ensis Directus In Europesupporting

confidence: 77%

“…No study has reported the disappearance of a native species related to the invasion of E. directus in Europe. Dannheim and colleagues, on the opposite, found that the presence of E. directus favored the settlement of some other deposit feeders (Dannheim and Rumohr 2012). In England, the fishing industry gets interested to harvest the razor clam stocks (the native species E. siliqua and E. arcuatus and the introduced species E. directus) as food source for human consumption (Pyke 2002).…”

Section: Projected Equatorward Expansion Of Ensis Directus In Europementioning

confidence: 99%

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Climate-induced range shifts of the American jackknife clam Ensis directus in Europe

et al. 2014

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Mapping the future potential distribution of alien species has become an issue of great concern. Ecological niche models are increasingly used to forecast the spatial range of introduced species in the context of climate warming. Here, we studied the potential spread of the American jackknife clam Ensis directus into European waters. E. directus, a marine bivalve native to the American coasts, was observed in Europe for the first time in the German Bight at the end of the 1970s. Afterwards, the clam quickly colonized the surrounding waters of the North Sea. Although many studies focused on its biology, ecology and colonization, the extent to which E. directus may invade European and Nordic seas remained poorly known. In this study, we used two ecological niche models (ENMs), calibrated on the native area of the mollusk, to evaluate the potential distributional range of the bivalve over European seas. Under current environmental conditions, E. directus should continue to progress towards the southern coasts of France and may also invade new areas in the Adriatic Sea. Projections for the end of the century suggest that the probability of occurrence of E. directus increases from Denmark to France with both ENMs. The Tunisian coasts may also become a new suitable area for the mollusk but the results of the two ENMs differ for this region. Therefore, contrary to what is often observed, a southward range expansion of E. directus is probable, especially as climate will get warmer.

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Section: Projected Equatorward Expansion Of Ensis Directus In Europesupporting

confidence: 77%

Section: Projected Equatorward Expansion Of Ensis Directus In Europementioning

confidence: 99%

Climate-induced range shifts of the American jackknife clam Ensis directus in Europe

et al. 2014

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“…Inspection of important spots used by the tagged birds revealed that herring gulls from Oland visited razor clam beds in the intertidal zone, although these were only available to herring gulls for a short time during low tide. Razor clams were accidently introduced to the Wadden Sea with ballast water in 1978 (Dannheim & Rumohr, 2012; Freudendahl, Nielsen, Jensen, & Jensen, 2010; von Cosel, Dörjes, & Mühlenhardt‐Siegel, 1982), and the species has since extended its range substantially over the last three decades (Dekker & Beukema, 2012). Common eiders, common scoters, and various shorebird and gull species regularly use this new source of food (Swennen, Leopold, & Stock, 1985; Tulp et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

Intercolony variations in movement patterns and foraging behaviors among herring gulls (Larus argentatus) breeding in the eastern Wadden Sea

Enners¹,

Schwemmer²,

Corman³

et al. 2018

Ecology and Evolution

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Herring gulls (Larus argentatus) are opportunistic predators that prefer to forage in the intertidal zone, but an increasing degree of terrestrial foraging has recently been observed. We therefore aimed to analyze the factors influencing foraging behavior and diet composition in the German Wadden Sea. Gulls from three breeding colonies on islands at different distances from the mainland were equipped with GPS data loggers during the incubation seasons in 2012–2015. Logger data were analyzed for 37 individuals, including 1,115 foraging trips. Herring gulls breeding on the island furthest from the mainland had shorter trips (mean total distance = 12.3 km; mean maximum distance = 4.2 km) and preferred to feed on the tidal flats close to the colony, mainly feeding on common cockles (Cerastoderma edule) and shore crabs (Carcinus maenas). In contrast, herring gulls breeding close to the mainland carried out trips with a mean total distance of 26.7 km (mean maximum distance = 9.2 km). These gulls fed on the neobiotic razor clams (Ensis leei) in the intertidal zone, and a larger proportion of time was spent in distant terrestrial habitats on the mainland, feeding on earthworms. δ 13C and δ 15N values were higher at the colony furthest from the mainland and confirmed a geographical gradient in foraging strategy. Analyses of logger data, pellets, and stable isotopes revealed that herring gulls preferred to forage in intertidal habitats close to the breeding colony, but shifted to terrestrial habitats on the mainland as the tide rose and during the daytime. Reduced prey availability in the vicinity of the breeding colony might force herring gulls to switch to feed on razor clams in the intertidal zone or to use distant terrestrial habitats. Herring gulls may thus act as an indicator for the state of the intertidal system close to their breeding colony.

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“…However, no studies have been published so far that support a suppression of native species by E. directus in European waters. Quite the opposite, both Armonies and Reise (1999) and Dannheim and Rumohr (2011) concluded that the newcomer might have favoured the appearance of some other species in the areas in which it occurs. Nowadays, E. directus is a commercial species in Europe (see Marine Stewardship Council 2012).…”

Section: Introductionmentioning

confidence: 99%

Population genetic analysis of Ensis directus unveils high genetic variation in the introduced range and reveals a new species from the NW Atlantic

et al. 2012

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The final publication is available at Springer via https://doi.org/10.1007/s00227-012-2006-6. How to cite:Vierna J, Jensen KT, González-Tizón A, Martínez-Lage A (2012) Population genetic analysis of Ensis directus unveils high genetic variation in the introduced range and reveals a new species from the NW Atlantic. Mar Biol 159: 2209-2227. AbstractWe report current genetic variation of populations of the razor shell Ensis directus (Conrad 1843) (Mollusca: Bivalvia: Pharidae) in native (North American) and introduced (European) ranges using nuclear and mitochondrial sequence-based markers. We expected less variation within the introduced range, especially considering the frequent mass mortality events observed in Europe since the species was recorded for the first time in 1978. However, we found higher variation in Europe. The possible significance of temporal fluctuations of genetic variation, limited effect of random genetic drift, and multiple introductions are discussed. Interestingly, the multiple-introduction hypothesis contrasts with the gradual colonisation of European coastal waters but is supported by trained clustering analysis and by the intensity of transatlantic shipping. Genetic and morphometric evidence strongly supports that examined individuals from a supposed E. directus population from Newfoundland (Canada) belong to a separate species. This new Ensis is formally described here and named E. terranovensis n.sp.In this work, we have studied nucleotide variation at four sequence-based molecular markers, including mitochondrial, nuclear multi-copy, and nuclear single-copy regions in order to: (1) compare current genetic variation in native and introduced ranges to assess to what extent potential bottlenecks and mass mortality events in Europe have impacted diversity, (2) obtain information about the possible origin of European individuals, and (3) study population structure in the native range of the species. Besides, we serendipitously detected a very divergent population from Conception Bay, Newfoundland (Canada) that is proposed to be a new Ensis species based on genetic and morphometric evidence. This new Ensis species from the NW Atlantic is formally described here. Materials and methods Specimens and lab proceduresWe studied a set of 148 razor shells from native and introduced sites (see Table 1; Fig. 1 for details). Razor shells were preserved in 100 % ethanol, and they were identified in the lab as E. directus according to shell morphology (Cosel 2009). Identifications of some of the specimens (Table 1) were confirmed by Rudo von Cosel (Muséum national d'Histoire naturelle, Paris, France) and included in his article on the taxonomy of Atlantic Ensis (Cosel 2009). One individual from the related species E. minor Dall, 1899 (collected off Christmas Bay, Texas, USA) was included as outgroup in some of the analyses.

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The fate of an immigrant: Ensis directus in the eastern German Bight

Cited by 26 publications

References 36 publications

Climate-induced range shifts of the American jackknife clam Ensis directus in Europe

Climate-induced range shifts of the American jackknife clam Ensis directus in Europe

Intercolony variations in movement patterns and foraging behaviors among herring gulls (Larus argentatus) breeding in the eastern Wadden Sea

Population genetic analysis of Ensis directus unveils high genetic variation in the introduced range and reveals a new species from the NW Atlantic

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