The effects of the adult density of Macoma balthica on the recruitment of juvenile bivalves: a field experiment
In: Journal of Sea Research. Elsevier/Netherlands Institute for Sea Research: Amsterdam; Den Burg. ISSN 1385-1101; e-ISSN 1873-1414, more
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| Keywords |
Developmental stages > Juveniles
Environmental factors > Biotic factors
Environments > Aquatic environment > Brackishwater environment
Interactions
Interspecific relationships > Predation
Population characteristics > Population density
Population functions > Recruitment
Carcinus maenas (Linnaeus, 1758) [WoRMS]; Cerastoderma edule (Linnaeus, 1758) [WoRMS]; Macoma balthica (Linnaeus, 1758) [WoRMS]
ANE, British Isles, Scotland, Firth of Forth [Marine Regions]
Marine/Coastal; Brackish water |
| Authors | | Top |
- Richards, M.
- Edwards, F.
- Huxham, M., correspondent
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| Abstract |
Populations of intertidal bivalves are patchily distributed at a variety of scales, and the distributions of adults and juveniles are often different. Adult-juvenile interactions may help explain this patchiness. In this study, the effects of different densities of adult Macoma balthica (L.) on the numbers of re-locating juvenile M. balthica and Cerastoderma edule (L.) were examined. Two field experiments were conducted, which established three densities of adult M. balthica (reflecting the range of values found on the study site) and allowed recruitment of bivalves into experimental plots for two tidal cycles. Both experiments were run at peak summer arrival of juveniles at this site. The first was open to predators, the second was protected from larger epibenthic and avian predators by cages. The mean number of juvenile C. edule found in the high-density treatment was significantly lower than in the other density treatments in the first (open) experiment. There was also evidence of density-dependent predation by Carcinus maenas (L.). There were no significant effects of adult M. balthica density on the numbers of juvenile bivalves in the caged experiment. These results were compared with those from a small-scale field survey, which showed a negative correlation between juvenile M. balthica less or equal to 1.6 mm and individuals more or equal to 1.6 mm. Our study suggests that densities of M. balthica more or equal to 1.6 mm may have an impact on the numbers of juvenile bivalves (in particular, C. edule) re-locating at this site, but that this effect is not the result of direct adult-juvenile interactions, but is caused indirectly by density-dependent predation by C. maenas. |
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