Float and Raft: Role of Buoyant Seaweeds in the Phylogeography and Genetic Structure of Non-buoyant Associated Flora

Macaya, Erasmo C.; López, Boris A.; Tala, Fadia; Tellier, Florence; Thiel, Martín

doi:10.1007/978-94-017-7534-2_4

Cited by 33 publications

(27 citation statements)

References 149 publications

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“…In contrast, S. dendroidea has been reported growing on stranded holdfasts of the floating alga Durvillaea antarctica (Macaya et al. , López et al. , ), which could contribute to dispersal after genetic differentiation influenced its genetic structure.…”

Section: Discussionmentioning

confidence: 99%

Widely distributed red algae often represent hidden introductions, complexes of cryptic species or species with strong phylogeographic structure

Díaz‐Tapia

Maggs

Macaya

et al. 2018

Journal of Phycology

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Despite studies suggesting that most seaweeds are poor dispersers, many red algal species are reported to have circumglobal distributions. Such distributions have mostly been based on morphological identifications, but molecular data have revealed a range of issues with morphologically defined species boundaries. Consequently, the real distribution of such reportedly circumglobal species must be questioned. In this study, we analyzed molecular data sets (rbcL gene) of nine species in the Rhodomelaceae for which samples were available from widely spaced geographical locations. Three overall patterns were identified: (i) species showing strong phylogeographic structure (i.e., phylogenetic similarity correlates with geographical provenance), often to the point that populations from different locations could be considered as different species (Lophosiphonia obscura, Ophidocladus simpliciusculus, Polysiphonia villum, and Xiphosiphonia pinnulata); (ii) species with a broad distribution that is explained, in part, by putative human-mediated transport (Symphyocladia dendroidea and Polysiphonia devoniensis); and (iii) non-monophyletic complexes of cryptic species, most with a more restricted distribution than previously thought (Herposiphonia tenella, Symphyocladia dendroidea, and the Xiphosiphonia pennata complex that includes the species Xiphosiphonia pinnulata and Symphyocladia spinifera). This study shows that widely distributed species are the exception in marine red algae, unless they have been spread by humans.

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Section: Discussionmentioning

confidence: 99%

Widely distributed red algae often represent hidden introductions, complexes of cryptic species or species with strong phylogeographic structure

Díaz‐Tapia

Maggs

Macaya

et al. 2018

Journal of Phycology

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“…, Macaya et al. ). Effective dispersal thus depends on seaweed availability and persistence but once afloat seaweeds suffer from biotic and abiotic stress (Rothäusler et al.…”

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confidence: 99%

High acclimation potential in floating Macrocystis pyrifera to abiotic conditions even under grazing pressure – a field study

Rothäusler

Reinwald

López

et al. 2018

Journal of Phycology

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The persistence of floating seaweeds, which depends on abiotic conditions but also herbivory, had previously been mostly tested in outdoor mesocosm experiments. In order to investigate if the obtained mesocosm results of high seaweed persistence under natural environmental conditions and under grazing pressure can be extrapolated to field situations, we conducted in situ experiments. During two summers (2007 and 2008), Macrocystis pyrifera was tethered (for 14 d) to lines in the presence and absence of the amphipod Peramphithoe femorata at three sites (Iquique, Coquimbo, Calfuco). We hypothesized that grazing damage and seaweed persistence vary among sites due to different abiotic factors. By incubating the sporophytes in mesh bags, we were either able to isolate (grazing) or exclude (control) amphipods. To test for a mesh bag artifact, a set of sporophytes was incubated without mesh bags (natural). Mesh bags used to exclude herbivores influenced sporophyte growth and physiological performance. The chlorophyll a (Chl a) content depended largely on grazers and grazed sporophytes grew less than natural and control sporophytes within the two summers. A decrease in Chl a content was found for the sites with the highest prevailing irradiances and temperatures, suggesting an efficient acclimation to these sea surface conditions. Our field‐based results of sporophyte acclimation ability even under grazing pressure widely align with previous mesocosm results. We conclude that M. pyrifera and other temperate floating seaweeds can function as long‐distance dispersal vectors even with hitchhiking mesoherbivores.

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“…with direct development or low mobility) but found frequently on floating seaweeds often have wider ranges than can be explained by their intrinsic dispersal capabilities. In line with these observations, the current geographic ranges of rafting epibionts are hypothesised to depend on (a) the dispersal ability of the floating substratum and its availability in coastal areas, (b) the biological interactions among epibionts and (c) their biological traits favouring long‐distance rafting journeys (Macaya, López, Tala, Tellier, & Thiel, ; Thiel & Gutow, ).…”

Section: Introductionmentioning

confidence: 90%

Epibiont communities on stranded kelp rafts of Durvillaea antarctica (Fucales, Phaeophyceae)—Do positive interactions facilitate range extensions?

López

Macaya

Rivadeneira

et al. 2018

Journal of Biogeography

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Aim This study examines how rafting on floating bull kelps can shape the biogeographic patterns of raft‐associated species, and analyses the spatio‐temporal variability of taxonomic richness and co‐occurrences of epibionts on beach‐cast rafts of Durvillaea antarctica along a latitudinal gradient. Location Southeast Pacific, along ~1,700 km of coastline. Methods We examined the epibionts on stranded individuals of D. antarctica on 33 beaches along the continental coast of Chile (28° S–42° S) within four biogeographic districts during the winter and summer of two years (2014/2015–2015/2016). Taxonomic richness and co‐occurrences of epibionts within a holdfast were examined. Known geographic ranges and rafting ranges were compared to determine possible range expansions via rafting dispersal. Results Sessile species were the most frequent epibionts. Taxonomic richness varied among biogeographic zones and seasons, and was higher between 33° S and 42° S than between 28° S and 33° S, particularly in summer compared to winter. Taxonomic richness decreased with floating time (indicated by the presence and size of Lepas spp.). Habitat‐forming epibionts such as mytilid mussels, the polychaete Phragmatopoma moerchi and the seaweeds Gelidium lingulatum and Lessonia spicata favoured co‐occurrences of other species within a holdfast, suggesting a habitat cascade (i.e. biogenic holdfast—sessile eco‐engineers—other epibionts), while the boring isopod Limnoria chilensis and the excavating limpet Scurria scurra were negatively correlated with many other species. Some rafting epibiont species with low dispersal ability were found more than 100–300 km outside of their known geographic ranges, with more extensive ephemeral range extensions at the southern edge of their respective ranges, probably facilitated by higher availability of rafts in those areas. Main Conclusions These findings confirm that raft‐associated species are frequently dispersed outside their known geographic ranges, although these range extensions vary strongly depending on the availability and persistence of rafts, and on the biotic interactions within the rafting assemblage.

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Float and Raft: Role of Buoyant Seaweeds in the Phylogeography and Genetic Structure of Non-buoyant Associated Flora

Cited by 33 publications

References 149 publications

Widely distributed red algae often represent hidden introductions, complexes of cryptic species or species with strong phylogeographic structure

Widely distributed red algae often represent hidden introductions, complexes of cryptic species or species with strong phylogeographic structure

High acclimation potential in floating Macrocystis pyrifera to abiotic conditions even under grazing pressure – a field study

Epibiont communities on stranded kelp rafts of Durvillaea antarctica (Fucales, Phaeophyceae)—Do positive interactions facilitate range extensions?

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