The paradox of Rockall: why is a brooding gastropod (Littorina saxatilis) more widespread than one having a planktonic larval dispersal stage (L. littorea)?

Johannesson, Kerstin

doi:10.1007/bf00392558

Cited by 290 publications

(227 citation statements)

References 32 publications

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“…This is supported by the fact that many brooding species have wider geographic distributions showing even more genetic connectivity on large scales than congeners with a planktonic larval stage (Highsmith 1985;Ó Foighil et al 2001;Nunes et al 2011;Hoeksema et al 2012;Xavier et al 2012). Passive dispersal through rafting and floating can greatly enhance natural dispersal in the marine environment and is supposed to be the main process leading to long-distance dispersal of these brooding marine invertebrates (Johannesson 1988;Locke and Corey 1989;Thiel and Gutow 2005b;Goodbody-Gringley et al 2010). Both natural (detached macroalgae, hydroids, and bryozoans) and artificial (buoys, pieces of wood or plastic, and ropes) floating substrata constitute ubiquitous dispersal agents for a wide diversity of organisms (Castilla and Guiñez 2000;Gutow et al 2006).…”

Section: Introductionmentioning

confidence: 73%

“…On the other hand, many marine species have direct development, lacking planktonic larvae, which imposes restrictions on their dispersal potential (Thiel 2003;Teske et al 2007). However, there is increasing evidence that the duration of pelagic stages is not directly correlated with dispersal potential (Johannesson 1988;Strathmann et al 2002). This is supported by the fact that many brooding species have wider geographic distributions showing even more genetic connectivity on large scales than congeners with a planktonic larval stage (Highsmith 1985;Ó Foighil et al 2001;Nunes et al 2011;Hoeksema et al 2012;Xavier et al 2012).…”

Section: Introductionmentioning

confidence: 99%

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Long-distance dispersal, low connectivity and molecular evidence of a new cryptic species in the obligate rafter Caprella andreae Mayer, 1890 (Crustacea: Amphipoda: Caprellidae)

et al. 2012

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The amphipod Caprella andreae Mayer, 1890 was recorded for the first time in Southern Iberian Peninsula (36°44 0 15 00 N, 3°59 0 38 00 W). This species is the only obligate rafter of the suborder Caprellidea and has been reported to attach not only to floating objects such as ropes or driftwoods but also to turtle carapaces. Mitochondrial and nuclear markers were used to examine dispersal capabilities and population genetic structure of C. andreae across seven localities in the Mediterranean and Atlantic Ocean collected from floating substrata with different dispersal patterns. The strong population differentiation with no haplotypes shared between populations suggests that C. andreae is quite faithful to the substratum on which it settles. In addition, the proportionally higher genetic diversity displayed in populations living on turtles as well as the presence of highly differentiated haplotypes in the same turtle population may be indicative that these populations survive longer, which could lead C. andreae to prefer turtles instead of floating objects to settle and disperse. Therefore, rafting on floating objects may be sporadic, and ocean currents would not be the most important factor shaping patterns of connectivity and population structure in this species. Furthermore, molecular phylogenetic analyses revealed the existence of a cryptic species whose estimates of genetic divergence are higher than those estimated between C. andreae and other congeneric species (e.g. Caprella dilatata and Caprella penantis). Discovery of cryptic species among widely distributed small marine invertebrates is quite common and, in this case, prompts for a more detailed phylogenetic analysis and taxonomic revision of genus Caprella. On the other hand, this study also means the first record of the gammarids Jassa cadetta and Elasmopus brasiliensis and the caprellid Caprella hirsuta on drifting objects.

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Section: Introductionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Long-distance dispersal, low connectivity and molecular evidence of a new cryptic species in the obligate rafter Caprella andreae Mayer, 1890 (Crustacea: Amphipoda: Caprellidae)

et al. 2012

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“…Hence a limited dispersal may allow a species to persist in a small, isolated fragment of suitable habitat (and by implication a small protected area). This mechanism is thought to explain how species with very limited dispersal persist on the island shores of Rockall while species with planktonic larvae do not (Johannesson, 1988). A reserve diameter of twice a species' dispersal scale has been suggested as a threshold size for retaining sufficient numbers of propagules to permit independent self-sustaining populations (mechanism l; Shanks et al, 2003).…”

Section: Connectivity Analysismentioning

confidence: 99%

Characterizing the marine Natura 2000 network for the Atlantic region

Johnson

Crowe

McAllen

et al. 2007

Aquatic Conservation

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One of the goals for Natura 2000, a key European Community programme of nature conservation, is to produce a network of protected areas. An analysis of the Natura 2000 marine sites proposed in the most recently agreed list for the Atlantic region (northern Portugal to Denmark, n=298) was used to characterize the network in terms of site areas and inter‐site distances. Sites were considered as part of the network when they included any of the marine Natura 2000 Annex I habitat types found in the Atlantic region (excluding lagoons). The median size of individual sites was 7.6 km2 with a median separation among neighbouring sites of 21 km (range 2–138 km). A connectivity analysis was used to identify the potential reliance of species on areas of habitat outside the proposed network. This analysis was based on the assumptions that: (a) species with low dispersal capacity will persist in sites when local reproductive effort sustains the resident population and (b) greater dispersal scale will link sites in the network, but implies a greater loss of recruits from the local population. For intermediate dispersal scales (2–20 km), at least half of the proposed sites are likely to be both too small and too isolated to support populations in the network. The conservation of intermediate dispersers in such sites may therefore be more dependent on habitat outside the network than is the case for other dispersal capabilities. Species with both dispersal scales above 20 km and low habitat specificity may have a metapopulation structure with exchange of dispersing individuals occurring among protected sites. Species with increasing degrees of habitat specificity will need dispersal scales greater than 20 km to avoid dependence on areas outside the proposed network. Most sections of the Atlantic region coastline contain proposed Nature 2000 sites. An analysis of site area and average isolation at the 1° latitude by 1° longitude scale indicated that relatively well designated sections (in terms of area and site spacing) of the coast were interspersed with less well designated sections. Analyses of overall habitat availability and population genetic studies are required to assess the significance of varying levels of protection at this scale. Copyright © 2007 John Wiley & Sons, Ltd.

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“…Low migratory activity can, thus, increase the probability for long distance dispersal. Efficient rafting dispersal can result in natural range expansion (Johannesson, 1988), colonization of new areas (Ó Foighil et al, 1999), and connectivity among local populations allowing for regional persistence of species through metapopulation effects (Thiel & Haye, 2006).…”

Section: Causes and Implications Of Rapid Migration After Algal Detacmentioning

confidence: 99%

Rapid changes in the epifaunal community after detachment of buoyant benthic macroalgae

et al. 2008

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Rafting on floating macroalgae is a common dispersal mechanism of marine benthic invertebrates. Most benthic macroalgae are inhabited by diverse epifaunal communities but not all organisms may be adapted to live on floating algae. In particular, knowledge about the immediate effects of algal detachment on the associated biota is limited. Herein, we studied the composition of the communities of mobile invertebrates on benthic thalli of Ascophyllum nodosum and compared it with detached thalli that had floated for short periods. The community of the mobile invertebrates changed significantly within the first minute after detachment of the algae and showed decreased diversity and a tendency towards reduced abundances in most taxa. However, during the subsequent two hours of floating at the sea surface the species composition did not change further. A comparison of the size-spectra of the gastropod Littorina obtusata from attached and detached algae did not reveal differential migratory activity among size-classes of these gastropods. Most of the species encountered in this study are common rafters in coastal and offshore waters, which are well capable of holding onto floating seaweeds. Therefore, our results indicate that the animals actively abandoned the macroalgae immediately after detachment. A benefit of this behaviour may be to avoid increased predation risk in the open water. The fact that individuals remain associated with their algal host after detachment indicates the importance of rafting dispersal for a great variety of phytal species that might lead to range expansion and regional population persistence through metapopulation effects.

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The paradox of Rockall: why is a brooding gastropod (Littorina saxatilis) more widespread than one having a planktonic larval dispersal stage (L. littorea)?

Cited by 290 publications

References 32 publications

Long-distance dispersal, low connectivity and molecular evidence of a new cryptic species in the obligate rafter Caprella andreae Mayer, 1890 (Crustacea: Amphipoda: Caprellidae)

Long-distance dispersal, low connectivity and molecular evidence of a new cryptic species in the obligate rafter Caprella andreae Mayer, 1890 (Crustacea: Amphipoda: Caprellidae)

Characterizing the marine Natura 2000 network for the Atlantic region

Rapid changes in the epifaunal community after detachment of buoyant benthic macroalgae

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