Dispersal and population expansion in a direct developing marine snail (Littorina saxatilis) following a severe population bottleneck
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Most marine benthic invertebrate species have planktonic larvae, and in species in which juveniles and adults have low vagility a larva is obviously an efficient way of active dispersal. A minority of benthic invertebrate species develop without any pelagic phase at all. A largely unsolved question is how and at what rate do these species disperse. We have addressed this question using the marine littoral snail Littorina saxatilis (Olivi) as an example of a species that completely lacks larval dispersal.
In the Koster archipelago (north part of the Swedish west coast), L. saxatilis occupies rocky island habitats of different sizes, from large islands to small intertidal skerries (islets). In 1988 an extremely dense bloom of a toxin-producing flagellate killed more than 99% of this snail species in this area. Populations of larger islands were reduced, often to less than 1%, but were restored over 2–4 yr. In contrast, populations of small intertidal skerries were completely wiped out and thus could not increase by local recruitment. Four years later, however, four of 33 skerries (12%) were successfully recolonized with relatively dense populations, and another five had received a few founder individuals. These results indicate recruitment through founder individuals, and are rough estimates of dispersal rate in a snail species that lacks a pelagic developmental stage.
Key wordscross water dispersal migration Chrysochromulina polylepis bloom rafting
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- Carlton, J. T., 1982. The historical biogeography of Littorina littorea on the Atlantic coast of North America, and implications for the interpretation of the structure of New England intertidal communities. Malacol. Rev. 15: 146.Google Scholar
- Fretter, V. & A. Graham, 1980. The prosobranch molluscs of Britain and Denmark. Part 5 — Marine Littorinacea. J. moll. Stud. Suppl. 7.Google Scholar
- Gerlach, S. A., 1977. Mean of meiofauna dispersal. Mikrofauna Meeresboden 61: 89–103.Google Scholar
- Janson, K., 1982. Phenotypic differentiation in Littorina saxatilis Olivi (Mollusca, Prosobranchia) in a small area on the Swedish west coast. J. moll. Stud. 48: 167–173.Google Scholar
- Janson, K. & R. D. Ward, 1985. The taxonomic status of Littorina tenebrosa Montagu as assessed by morphological and genetic analyses. J. Conch. 32: 9–15.Google Scholar
- Johannesson, K., 1992. Genetic variability and large scale differentiation in two species of littorinid gastropods with planktotrophic development, Littorina littorea (L.) and Melarhaphe (Littorina) neritoides (L.) (Prosobranchia: Littorinacea), with notes on a mass occurrence of M. neritoides in Sweden. Biol. J. linn. Soc. 47: 285–299.CrossRefGoogle Scholar
- Lewis, J. R., 1972. The ecology of rocky shores. The English Universities Press, London, 323 pp.Google Scholar
- Loberg, B. 1980. Geologi. Material, processer och Sveriges berggrund. Norstedts, Stockholm, 302 pp.Google Scholar
- Rosenberg, R., O. Lindahl, & H. Blanck, 1988. Silent spring in the sea. Ambio 17: 289–290.Google Scholar
- Underwood, A. J., 1981. Techniques of analysis of variance in experimental marine biology and ecology. Oceanogr. Mar. Biol. annu Rev. 19: 513–605.Google Scholar