When Invaders Go Unnoticed: The Case of<i>Gracilaria vermiculophylla</i>in the British Isles

Krueger‐Hadfield, Stacy A.; Magill, Caroline L.; Bunker, Francis; Mieszkowska, Nova; Sotka, Erik E.; Maggs, Christine A.

doi:10.7872/crya/v38.iss4.2017.379

Cited by 11 publications

(17 citation statements)

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“…Miller, unpublished data). This oversight may reflect the fact that phycologists are more likely to study rocky shores than soft‐sediment estuaries where G. vermiculophylla has largely invaded, or the fact that cryptic species are common in seaweeds (Krueger‐Hadfield, Magill, Mieszkowska, Sotka, & Maggs, ). An analogous example comes from Provan, Booth, Todd, Beatty, and Maggs (), who used herbarium specimens coupled with molecular markers to conclude that the invasive strain of Codium fragile spp.…”

Section: Discussionmentioning

confidence: 99%

“…Gracilaria vermiculophylla is now recognized as one of the most widespread and abundant marine invaders in the Northern Hemisphere (Kim et al, 2010;Krueger-Hadfield et al, 2016;Saunders, 2009) and has transformed the ecosystems to which it has been introduced (Byers et al, 2012;Thomsen, Wernberg, Tuya, & Silliman, 2009 This oversight may reflect the fact that phycologists are more likely to study rocky shores than soft-sediment estuaries where G. vermiculophylla has largely invaded, or the fact that cryptic species are common in seaweeds (Krueger-Hadfield, Magill, Mieszkowska, Sotka, & Maggs, 2017). An analogous example comes from Provan, Booth, Todd, Beatty, and Maggs (2007), who used herbarium specimens coupled with molecular markers to conclude that the invasive strain of Codium fragile spp.…”

Section: Discussionmentioning

confidence: 99%

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Genetic identification of source and likely vector of a widespread marine invader

Krueger‐Hadfield

Kollars

Strand

et al. 2017

Ecology and Evolution

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153

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The identification of native sources and vectors of introduced species informs their ecological and evolutionary history and may guide policies that seek to prevent future introductions. Population genetics provides a powerful set of tools to identify origins and vectors. However, these tools can mislead when the native range is poorly sampled or few molecular markers are used. Here, we traced the introduction of the Asian seaweed Gracilaria vermiculophylla (Rhodophyta) into estuaries in coastal western North America, the eastern United States, Europe, and northwestern Africa by genotyping more than 2,500 thalli from 37 native and 53 non‐native sites at mitochondrial cox1 and 10 nuclear microsatellite loci. Overall, greater than 90% of introduced thalli had a genetic signature similar to thalli sampled from the coastline of northeastern Japan, strongly indicating this region served as the principal source of the invasion. Notably, northeastern Japan exported the vast majority of the oyster Crassostrea gigas during the 20th century. The preponderance of evidence suggests G. vermiculophylla may have been inadvertently introduced with C. gigas shipments and that northeastern Japan is a common source region for estuarine invaders. Each invaded coastline reflected a complex mix of direct introductions from Japan and secondary introductions from other invaded coastlines. The spread of G. vermiculophylla along each coastline was likely facilitated by aquaculture, fishing, and boating activities. Our ability to document a source region was enabled by a robust sampling of locations and loci that previous studies lacked and strong phylogeographic structure along native coastlines.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Genetic identification of source and likely vector of a widespread marine invader

Krueger‐Hadfield

Kollars

Strand

et al. 2017

Ecology and Evolution

Self Cite

153

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“…heterozygote excess) for extreme rates of clonality (Stoeckel & Masson, 2014) but also for modest rates of clonality (Reichel, Masson, Malrieu, Arnaud‐Haond, & Stoeckel, 2016) as long as the equilibrium is not reached. These findings were more recently used to broaden the interpretation of deviations from HWE as indicative of partial (though not necessarily extreme) clonality in organisms such as invasive algae (Krueger‐Hadfield et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

New insights into the population genetics of partially clonal organisms: When seagrass data meet theoretical expectations

2020

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Seagrass meadows are among the most important coastal ecosystems in terms of both spatial extent and ecosystem services, but they are also declining worldwide. Understanding the drivers of seagrass meadow dynamics is essential for designing sound management, conservation and restoration strategies. However, poor knowledge of the effect of clonality on the population genetics of natural populations severely limits our understanding of the dynamics and connectivity of meadows. Recent modelling approaches have described the expected distributions of genotypic and genetic descriptors under increasing clonal rates, which may help us better understand and interpret population genetics data obtained for partial asexuals. Here, in the light of these recent theoretical developments, we revisited population genetics data for 165 meadows of four seagrass species. Contrasting shoot lifespan and rhizome turnover led to the prediction that the influence of asexual reproduction would increase along a gradient from Zostera noltii to Zostera marina, Cymodocea nodosa and Posidonia oceanica, with increasing departure from Hardy–Weinberg equilibrium (Fis), mostly towards heterozygote excess, and decreasing genotypic richness (R). This meta‐analysis provides a nested validation of this hypothesis at both the species and meadow scales through a significant relationship between Fis and R within each species. By empirically demonstrating the theoretical expectations derived from recent modelling approaches, this work calls for the use of Hardy–Weinberg equilibrium (Fis) rather than only the strongly sampling‐sensitive R to assess the importance of clonal reproduction (c), at least when the impact of selfing on Fis can be neglected. The results also emphasize the need to revise our appraisal of the extent of clonality and its influence on the dynamics, connectivity and evolutionary trajectory of partial asexuals in general, including in seagrass meadows, to develop the most accurate management strategies.

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“…, Krueger‐Hadfield et al. , Niklas and Cobb ), then complex triphasic haploid–diploid life histories that amplify the reproductive output from individual fertilization events (sensu Searles ) may be selected for unstable environments (Klinger ), but subtle ecological differences amongst phases may serve to maintain the complex life cycles (Hughes and Otto ), even under stable conditions. However, several studies examining intraspecific genetic diversity have shown that fertilization success of male and female gametes can be high and sexual reproduction common amongst some isomorphic red algae (including Chondrus crispus , congeneric with our study species; Engel et al.…”

Section: Discussionmentioning

confidence: 99%

Maintenance of Complex Life Cycles Via Cryptic Differences In The Ecophysiology Of Haploid And Diploid Spores Of An Isomorphic Red Alga¹

Bellgrove

Nakaya

Serisawa

et al. 2019

Journal of Phycology

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Recognition of the wide diversity of organisms that maintain complex haploid-diploid life cycles has generated interest in understanding the evolution and persistence of such life cycles. We empirically tested the model where complex haploid-diploid life cycles may be maintained by subtle/cryptic differences in the vital rates of isomorphic haploid-diploids, by examining the ecophysiology of haploid tetraspores and diploid carpospores of the isomorphic red alga Chondrus verrucosus. While tetraspores and carpospores of this species did not differ in size or autofluorescence, concentrations of phycobiliproteins of carpospores were greater than that of tetraspores. However, tetraspores were more photosynthetically competent than carpospores over a broader range of photosynthetic photon flux densities (PPFDs) and at PPFDs found at both the depth that C. verrucosus is found at high tide and in surface waters in which planktonic propagules might disperse. These results suggest potential differences in dispersal potential and reproductive success of haploid and diploid spores. Moreover, these cryptic differences in ecological niche partitioning of haploid and diploid spores contribute to our understanding of some of the differences between these ploidy stages that may ultimately lead to the maintenance of the complex haploid-diploid life cycle in this isomorphic red alga.Abbreviations: PPFD, photosynthetic photon flux density Sexual eukaryotes undergo an alternation of haploid and diploid generations, with varying levels of complexity, including (i) diploid life cycles (diploid 1

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When Invaders Go Unnoticed: The Case ofGracilaria vermiculophyllain the British Isles

Cited by 11 publications

References 53 publications

Genetic identification of source and likely vector of a widespread marine invader

Genetic identification of source and likely vector of a widespread marine invader

New insights into the population genetics of partially clonal organisms: When seagrass data meet theoretical expectations

Maintenance of Complex Life Cycles Via Cryptic Differences In The Ecophysiology Of Haploid And Diploid Spores Of An Isomorphic Red Alga¹

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When Invaders Go Unnoticed: The Case ofGracilaria vermiculophyllain the British Isles

Cited by 11 publications

References 53 publications

Genetic identification of source and likely vector of a widespread marine invader

Genetic identification of source and likely vector of a widespread marine invader

New insights into the population genetics of partially clonal organisms: When seagrass data meet theoretical expectations

Maintenance of Complex Life Cycles Via Cryptic Differences In The Ecophysiology Of Haploid And Diploid Spores Of An Isomorphic Red Alga1

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Maintenance of Complex Life Cycles Via Cryptic Differences In The Ecophysiology Of Haploid And Diploid Spores Of An Isomorphic Red Alga¹