Seaweed invasions: conclusions and future directions

Johnson, Craig R.

doi:10.1515/bot.2007.047

Cited by 9 publications

(10 citation statements)

References 61 publications

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“…This is in accordance with other studies which have found that C. fragile can support many species of fauna (Schmidt & Scheibling, 2006;Drouin et al, 2011), and that introduced macroalgae in general do not have severe negative effects on diversity (e.g. Johnson, 2007;Thomsen et al, 2009;Engelen et al, 2013). Few taxa were completely absent from one of the host species, a pattern which has also been seen in other comparisons of non-native and native algae (e.g.…”

Section: Discussionsupporting

confidence: 92%

Epiphytic macroalgae mediate the impact of a non-native alga on associated fauna

Armitage

Sjøtun

2016

Hydrobiologia

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The introduction of a non-native, habitatforming macroalga may have impacts on the seaweedassociated faunal community. Codium fragile subsp. fragile is a well-known and widespread algal invader that may compete with native habitat-forming macroalgae and affect ecosystem services. This alga can be abundant at semi-exposed/sheltered sites on the south-west coast of Norway, where its vertical distribution range overlaps with another canopy-forming alga, the native Fucus serratus. Whether these seaweeds support similar or dissimilar associated communities will influence the ecological impact of C. fragile subsp. fragile. Therefore, the richness and composition of fauna associated with these species was assessed by sampling at three localities. While the majority of taxa occurred on both F. serratus and C. fragile subsp. fragile, there were clear differences in community composition between them. Fauna taxa richness and community composition were also related to macroalgal epiphyte abundance, and there were a number of taxa associated to high epiphyte samples.The results suggest that shared macroalgal epiphytes lead to higher similarity between the invertebrate communities associated with C. fragile subsp. fragile and F. serratus, providing correlative evidence that epiphytic macroalgae play a role in shaping the impact of this macroalga on associated fauna.

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Section: Discussionsupporting

confidence: 92%

Epiphytic macroalgae mediate the impact of a non-native alga on associated fauna

Armitage

Sjøtun

2016

Hydrobiologia

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“…Introduced seaweeds can account for a significant proportion of the total aquatic flora (Johnson, 2007), and about 260 species have now been identified as alien to their native range (Hewitt et al, 2007). In some cases, these invaders, freed of the natural controls of their native range, can proliferate in new waterways, displace native species and significantly degrade ecosystems.…”

Section: Introductionmentioning

confidence: 99%

When anthropogenic translocation meets cryptic speciation globalized bouillon originates; molecular variability of the cosmopolitan freshwater cyclopoidMacrocyclops albidus(Crustacea: Copepoda)

Karanovic

Krajíček

2012

Ann. Limnol. - Int. J. Lim.

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-Invasive species are a global problem, which costs the world economy billions of dollars and world ecosystems millions of tons of herbicides, pesticides and other cides. Anthropogenic translocation of freshwater copepods associated with early shipping activities was postulated for some time, but was never tested with molecular tools. Here, we examine global molecular diversity of one cyclopoid species, test if the current cosmopolitan distribution is a result of anthropogenic translocation or natural dispersal, and investigate a possibility of cryptic speciation. We use patterns of haplotype frequency of DNA and RNA sequences of four genes (12S, 16S, 18S and cytB) and 11 populations (from England, Scotland, France, Germany, USA, New Zealand and Australia) to test inter-and intrapopulation variability, and three different methods (neighbour joining (NJ), maximum likelihood (ML) and maximum parsimony (MP)) for reconstructing their phylogenetic relationships. They were then tested against two competing hypotheses, and complemented by comparative morphology of microcharacters. Reconstructed phylogenies present strong evidence for anthropogenic translocation, with the same haplotype found in highly disjunct populations in Western Australia, Germany and the USA. Four different clades were revealed with the 12S, 16S and cytB genes, probably representing four cryptic species. Morphological examination of females of two clades contributed a set of microcharacters that can be used in the future taxonomic revision of this species complex. We prove for the first time that cuticular pores and sensilla are homologous structures. This research provides evidence for both homogenization of world freshwater fauna and our inadequate methods of identifying some of its most common species.

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“…Invasive species in most cases dominate native algal communities, while eutrophication increases primary production, inducing blooms of opportunistic algae capable of rapidly exploiting the elevated amounts of nutrients (Duarte 1995;Johnson 2007;Johnson and Chapman 2007). These processes produce changes in the structure of algal communities, and consequently in the associated benthic fauna (Buschbaum et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Effects of the alien algae Undaria pinnatifida (Phaeophyceae, Laminariales) on the diversity and abundance of benthic macrofauna in Golfo Nuevo (Patagonia, Argentina): potential implications for local food webs

et al. 2010

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Changes in macroalgal community structure caused by invasive seaweeds have strong impacts on the associated macrofauna due to the role of macroalgae as autogenic ecosystem engineers. This study investigates the effect of Undaria pinnatifida on the abundance and diversity of benthic macrofauna in Golfo Nuevo, northern Patagonia, using a manipulative experiment involving the systematic removal of Undaria microthalli from strips of hard bottom during its eighth-month growing period. Species richness and diversity were higher in plots covered by Undaria than when Undaria was removed. Also, the abundance of two species of crustaceans, one species of sea urchin, one species of nemertina and several species of polychaetes was higher. We attribute these effects to the provision of new habitat structure by Undaria, a larger and structurally more complex species than the local native seaweeds. These results support the hypothesis that complex habitats enhance abundance and species richness, by offering different shelter and foraging opportunities compared to morphologically simpler habitats. Based on a review of diet studies in the region, we speculate that Undaria could potentially produce a bottom-up effect on local food chains by increasing abundance of prey for a wide variety of predators, from invertebrates to marine mammals. While our study has a narrow temporal and spatial scale, we expect similar effects of Undaria on the macrofauna in other sites of the Argentine coast, especially those dominated by small native macroalgae.

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Seaweed invasions: conclusions and future directions

Cited by 9 publications

References 61 publications

Epiphytic macroalgae mediate the impact of a non-native alga on associated fauna

Epiphytic macroalgae mediate the impact of a non-native alga on associated fauna

When anthropogenic translocation meets cryptic speciation globalized bouillon originates; molecular variability of the cosmopolitan freshwater cyclopoidMacrocyclops albidus(Crustacea: Copepoda)

Effects of the alien algae Undaria pinnatifida (Phaeophyceae, Laminariales) on the diversity and abundance of benthic macrofauna in Golfo Nuevo (Patagonia, Argentina): potential implications for local food webs

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