Lack of COI variation for Clavelina oblonga (Tunicata, Ascidiacea) in Brazil: Evidence for its human-mediated transportation?

Eggleston

2017

Ecological Monographs

Abstract. Predictions of ecological patterns can be strengthened through replication of foundational studies under different environmental conditions to evaluate the consistency in their underlying processes. In this study, we replicated Sutherland and Karlson's classic ecology study that tested terrestrial paradigms of community development in a marine fouling community. The abundance patterns of marine fouling species were quantified on sequentially submerged settlement plates to investigate the effects of disturbance date on short-and long-term patterns of community development, and the original study's data sets were reanalyzed for comparison. In both studies, community structure was initially shaped by disturbance date due to monthly and annual variation in larval recruitment; however, the influence of disturbance date diminished over time. Despite these similarities, the underlying drivers of long-term patterns of community development have shifted substantially since the 1970s. During the present study, an exotic tunicate, Clavelina oblonga, dominated plates over time and its dominance was associated with significant declines in species diversity. In contrast, the 1970s long-term community was characterized by a heterogeneous mixture of species that varied inter-annually, yielding increased species diversity over time. Continued observations of our settlement plates (2 yr total) indicated that C. oblonga remains the dominant species in this community, suggesting that these findings are not the result of a single, novel recruitment event. These results highlight how an exotic species can alter patterns of community development and biodiversity. Moreover, this study demonstrates the need to replicate foundational ecological studies to evaluate community dynamics and underlying processes in light of ongoing ecosystem change.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Long-term Community Development Patternsmentioning

confidence: 99%

See 1 more Smart Citation

An exotic species alters patterns of marine community development

Eggleston

2017

Ecological Monographs

Regional Studies in Marine Science

“…155 Clavelina lepadiformis (Müller, 1776) was described in the NE Atlantic and has expanded 156 to other areas (Azores, Madeira, South Africa, NW Atlantic and NW Pacific (Wirtz 1998 161 Clavelina oblonga Herdman, 1880 is native to the Caribbean area and was introduced in 162 Brazil and NE Atlantic (Rocha et al 2012). It has been recently reported from the 163 Mediterranean (Ordóñez et al 2016).…”

mentioning

confidence: 99%

Seasonal patterns of settlement and growth of introduced and native ascidians in bivalve cultures in the Ebro Delta (NE Iberian Peninsula)

Casso

Navarro

Ordóñez

et al. 2018

Abstract17 Ascidians are important both as invasive species and as a fouling group in artificial marine 18 habitats, causing negative impacts in aquaculture settings and the surrounding 19 environment. The Ebro Delta is one of the major centres of bivalve production in the 20 Mediterranean and is affected by proliferation of ascidian species (mostly introduced 21 forms). Knowledge of the patterns of settlement and growth of the fouling species is 22 mandatory to attempt mitigation measures. We deployed settlement PVC plates from May 23 to September 2015 at different depths (0.2, 1 and 2 m) in the Ebro Delta oyster 24 aquaculture facilities. We then monitored the occurrences of all species and the area cover 25 of a selected subset of 6 species on a monthly basis from June 2015 to December 2016. 26 We found 15 species, of which 10 are introduced. There were some differences between 27 our plates and the oyster ropes in species abundance and composition, likely due to 28 differences in substrate complexity. For instance, Didemnum vexillum and Clavelina 29 oblonga occurred in few plates in contrast to their abundance on oysters. The most 30 abundant species were Styela plicata and Clavelina lepadiformis, which together with 31 Ecteinascidia turbinata showed a preference to grow on plates deployed in May and June. 32 Most of the species grew more at 0.2 m depth than at deeper plates. Thus, to minimise 33 fouling on bivalves, we propose spat immersion during fall and below 1 m depth. We also 34 found that number of occurrences and cover of the species are similarly informative; we 35 suggest that a periodic monitoring of species occurrence on replicate plates is sufficient for 36 detecting new introduced species as soon as possible and will provide information useful 37 for management.

“…In this context, we aimed to contribute with future taxonomic studies on this ascidian, and also with management conservation programs for the studied areas. Our study was based on a segment of the mt encoding gene COI, a commonly used marker in molecular studies of ascidians (e.g., Pineda et al, 2011;Rocha et al, 2012;Bock et al, 2012;Wiernes et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Cryptic species and genetic structure in Didemnum granulatum Tokioka, 1954 (Tunicata: Ascidiacea) from the southern Brazilian coast

et al. 2014

Didemnum granulatum is a colonial fouling ascidian that lives in subtidal substrates, worldwide. It exhibits two morphotypes, orange and beige. In this study, we verified if the color morphotypes and/or the spatial distribution of specimens in different islands might be associated to patterns of genetic structure of a single species, or if they represent distinct cryptic species. Specimens were collected in four islands, along the coast of the Santa Catarina state. A segment of 490 bp from the mitochondrial gene cytochrome c oxidase subunit 1 (COI) was amplified from 45 samples. Twenty-one haplotypes were identified. The total haplotype diversity (0.912) and the total nucleotide diversity (0.044) were high. The global Fst of the populations analyzed was 0.97, with most of the variation occurring between orange and beige groups (82.19%). The variation found between populations within groups was 15.37%, and 2.45% within populations. Haplotype networks and the neighbor-joining tree showed clear genetic divergence between individuals of distinct colors, and between the islands. These evidences strongly support the presence of a complex of two cryptic species for D. granulatum occupying the studied area. Both species were also highly genetically structured between islands, suggesting that the conservation process of these populations is complex.Keywords: ascidian, genetic diversity, population structure, islands, cryptic species. Palavras-chave: ascídia, diversidade genética, estrutura de população, ilhas, espécies crípticas. Espécies crípticas e estrutura genética em