Aspects of the Ecology of Sargassum Muticum (Yendo) Fensholt, in the Solent Region of the British Isles. I. The Growth Cycle and Epiphytes

Jephson, N. A.; Gray, P. W. G.

doi:10.1016/b978-0-08-021378-1.50041-5

Cited by 43 publications

(62 citation statements)

References 5 publications

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“…Since the growth of Sargassum muticum in the Wadden Sea is pseudo-perennial, the algal biomass decreases drastically during late summer and early fall, when lateral branches detach (Jephson & Gray 1977, Buschbaum et al 2006. Therefore, S. muticum habitats are only temporarily available and do not support a resident fish fauna.…”

Section: Discussionmentioning

confidence: 99%

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Native pipefish Entelurus aequoreus are promoted by the introduced seaweed Sargassum muticum in the northern Wadden Sea, North Sea

Polte¹,

Buschbaum²

2008

Aquat. Biol.

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After the major loss of eelgrass habitats in the 1930s the snake pipefish Entelurus aequoreus was considered to be rare in the Wadden Sea (south-eastern North Sea, German Bight). We hypothesize that a sudden increase in pipefish abundance observed in the area since 2004 is related to new habitats provided by the introduced Japanese seaweed Sargassum muticum. SCUBA observations conducted near the Island of Sylt during July 2006 showed that approximately every second S. muticum thallus was inhabited by E. aequoreus, whereas no pipefish could be found on sedimentary areas dominating the Wadden Sea. In a field experiment, we removed thalli from a S. muticum bed and transplanted them to an unvegetated site and to the donor S. muticum bed, respectively. Nine days after the transplantation, abundances of pipefish per thallus were almost equally high within all transplanted S. muticum units at vegetated and originally unvegetated sites. Abundances of E. aequoreus in transplanted thalli did not significantly differ from those found in unaffected control thalli located in the donor S. muticum bed. To explain high pipefish densities within S. muticum beds we sampled the zooplankton community inside and outside the S. muticum bed and compared it with gut contents of pipefish. Zooplankton densities were significantly higher inside the S. muticum bed. Harpacticoid copepods were the dominant group associated with S. muticum and also represented the major prey of E. aequoreus. We conclude that stocks of E. aequoreus are promoted by S. muticum beds since they benefit from higher food supply during the spawning season, probably in addition to increased shelter by habitat complexity. Results of the present study suggest that introductions of habitat-forming species such as S. muticum may cause beneficial effects on abundance and diversity of native species.

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Section: Discussionmentioning

confidence: 99%

“…The lateral branches detach in summer and early autumn, leaving a short perennial stipe from which thalli regenerate during the following spring (e.g. Jephson & Gray 1977) and may achieve a length of > 4 m during summer. Other habitat-forming algae are very rare in the subtidal zone of the Wadden Sea.…”

Section: Introductionmentioning

confidence: 99%

Native pipefish Entelurus aequoreus are promoted by the introduced seaweed Sargassum muticum in the northern Wadden Sea, North Sea

Polte¹,

Buschbaum²

2008

Aquat. Biol.

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“…Jephson and Gray 1977;Critchley et al 1987;Ferna´ndez 1999). Thus, each year the associated species community is lost with the branches shed, and an annual re-colonisation of the alga is necessary because only few species stay attached to the basal system, maintaining their presence over winter (Norton and Benson 1983;Jephson and Gray 1977). This may explain why species communities in both environments differ so clearly from one another, and why almost all species found associated with S. muticum on Helgoland and Sylt originate from the regional species pool of the respective environments.…”

Section: Epibiota Of Sargassum Muticum In Different Coastal Systemsmentioning

confidence: 94%

“…The lateral branches detach in summer and early autumn, leaving only a short perennial stipe from which branches regenerate during the following spring (e.g. Jephson and Gray 1977;Critchley et al 1987;Ferna´ndez 1999). Thus, each year the associated species community is lost with the branches shed, and an annual re-colonisation of the alga is necessary because only few species stay attached to the basal system, maintaining their presence over winter (Norton and Benson 1983;Jephson and Gray 1977).…”

Section: Epibiota Of Sargassum Muticum In Different Coastal Systemsmentioning

confidence: 99%

How an introduced seaweed can affect epibiota diversity in different coastal systems

2005

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Invasions by non-indigenous species have the potential to alter the biodiversity of recipient systems. The magnitude of this effect often depends on the nature of the invaded communities and the ecology of the invader. We investigated the impacts of the Japanese seaweed Sargassum muticum (Phaeophyceae, Fucales) on biodiversity in a rocky and sedimentary environment on two islands in the North Sea. In each case, we compared the epibiota of non-indigenous S. muticum with epibiota communities on taxonomically related and structurally similar native seaweed hosts. Total and average species richness on S. muticum were similar on the rocky shore (60 species and 22±6 species, respectively) and the sandy shore (64 species and 20±3 species, respectively). However, community structure and species composition differed significantly between the environments. On the rocky shore, another native fucoid seaweed, Halidrys siliquosa, supported an epibiota community very similar to that of the invader. On the sandy shore, the only other abundant native habitat-providing algal species was Fucus vesiculosus. This species supported a different and less diverse assemblage of associated taxa. We conclude that S. muticum enhances epibiota diversity in the sedimentary environment, probably by increasing the substratum availability and habitat heterogeneity. In contrast, it has negligible impacts on epibiota diversity in the rocky shore environment, where it does not represent a fundamentally new habitat component. We conclude that even within the same region, the consequences of non-indigenous species on biodiversity cannot be generalised but depend on the composition and structural complexity of the species in the recipient community.

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“…Several studies have indicated negative impacts by S. muticum on indigenous algal assemblages (Fletcher and Fletcher 1975;Ambrose and Nelson 1982;Viejo 1997;Cosson 1999;Staehr et al 2000) but only a limited number of studies have addressed the possible consequences for macroalgal epibiota. Those that have, have suggested few adverse effects, apparently due to a low degree of habitat specificity among the epibiota (Withers et al 1975;Jephson and Gray 1977;Viejo 1999). Nevertheless, following the introduction of S. muticum to Limfjorden, a shallow Danish sound, biologists noted conspicuously more epibiota associated with S. muticum relative to other algae (M. Lauersen, County of Ringkøbing, personal communication).…”

Section: Introductionmentioning

confidence: 99%

Epibiota communities of the introduced and indigenous macroalgal relatives Sargassum muticum and Halidrys siliquosa in Limfjorden (Denmark)

et al. 2004

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Sargassum muticum (Phaeophyceae, Fucales) has recently been introduced to Limfjorden (Denmark) where its closest relative is the indigenous Halidrys siliquosa. Previous studies have demonstrated large quantitative (canopy biomass) and qualitative (canopy persistence) differences in the habitat available to epibiota within the canopies of these two macroalgae. We therefore hypothesised that these algae would support different epibiota communities and tested this by sampling the epibiota of S. muticum and H. siliquosa on seven occasions throughout 1997 by enclosing entire thalli in mesh bags. We found 53 epibiota taxa and, with only one exception, they were all recorded on both host species. Species richness and abundance of epibiota exhibited clear seasonal variation on both host species, although epibiota biomass was seasonally constant on H. siliquosa but not on S. muticum. These patterns were consistent with the different life histories of the host species. There was a weakly negative correlation between thallus size and epibiota biomass for both host species. When taking species-specific seasonal variation in thallus size into consideration, S. muticum and H. siliquosa were found to support significantly different epibiota biomasses. Multivariate analyses showed that epibiota community structure was different, although highly overlapping, between the two species, whereas there was an almost parallel temporal development in epibiota community structure. We conclude that it is unlikely that the introduction of S. muticum to Limfjorden has caused major changes in local epibiota community structure. However, the standing stock of epibiota is likely to have increased.

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Aspects of the Ecology of Sargassum Muticum (Yendo) Fensholt, in the Solent Region of the British Isles. I. The Growth Cycle and Epiphytes

Cited by 43 publications

References 5 publications

Native pipefish Entelurus aequoreus are promoted by the introduced seaweed Sargassum muticum in the northern Wadden Sea, North Sea

Native pipefish Entelurus aequoreus are promoted by the introduced seaweed Sargassum muticum in the northern Wadden Sea, North Sea

How an introduced seaweed can affect epibiota diversity in different coastal systems

Epibiota communities of the introduced and indigenous macroalgal relatives Sargassum muticum and Halidrys siliquosa in Limfjorden (Denmark)

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