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Januario S, Estay SA, Labra FA, Lima M.2015. Combining environmental suitability and population abundances to evaluate the invasive potential of the tunicate Ciona intestinalis along the temperate South American coast. PeerJ PrePrints3:e1281v1https://doi.org/10.7287/peerj.preprints.1281v1
The tunicate Ciona intestinalis is an opportunistic invader with high potential for causing economic losses in aquaculture centers. Recent phylogenetic and population genetic analysis support the existence of a genetic complex described as C. intestinalis with two main dominant species (sp A and B) occurring worldwide. In Chile, the species has been observed around 30o S of latitude, but no official reports exist for the presence of C. intestinalis in southern regions (above 40o S), where most of the mollusk aquaculture centers are located. Here, we used occurrences from multiple invaded regions and extensive field sampling to model and validate the environmental conditions that allow the species to persist and to find the geographic areas with the most suitable environmental conditions for the spread of C. intestinalis in the Chilean coast. By studying the potential expansion of C. intestinalis southward in the Chilean Coast, we aimed to provide valuable information that might help the development of control plans before the species becomes a significant problem, especially above 40o S. Our results highlight that, by using portions of the habitat that are apparently distinguishable, the species seem to be not only genetically distinct, but ecologically distinct as well. The two regional models fitted for sp A and for sp B showed disagreement on which sections of Chilean coastline are considered more suitable for these species. While the model for sp A identifies moderately to highly suitable areas between 30o and 40o S, the model for sp B classifies the areas around 45o S as the most appropriate. Data from field sampling show a positive linear relationship between density of C. intestinalis and the index of suitability for sp A in aquaculture centers. Understanding the relation of the distinct species with the surrounding environment provided valuable insights about probable routes of dispersion in Chile, especially into those areas considered suitable for aquaculture activities but where the species has not yet been recorded. We discuss the implications of our findings as a useful tool to anticipate the invasion of such harmful invasive species with regard to the most relevant environmental variables.
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Figures 1 and 2. Projections of the potential distribution of C. intestinalis on Chilean coast
Projections of the potential distribution of C. intestinalis on Chilean coast using non analog environments for each of the five locations used in the analysis.
Recent papers resolved the taxonomic issue about Ciona intestinalis A and B and the species present in Chile is actually C. robusta. I have collaborated in a study on Chilean introduced species and we barcoded Ciona, and confirmed sp. A identification at the time. The manuscript is in review.
You might want to update your manuscript title and replace sp A and sp B by their actual names along the text.
Brunetti et al 2015 Morphological evidence that the molecularly determined Ciona intestinalis type A and type B are different species: Ciona robusta and Ciona intestinalis. J Zoolog Syst Evol Res doi: 10.1111/jzs.12101
Pennati et al 2015 Morphological Differences between Larvae of the Ciona intestinalis Species Complex: Hints for a Valid Taxonomic Definition of Distinct Species. PLosONE 10.1371/journal.pone.0122879
And if you do not have access to the papers, just ask me.