EASIN - European Alien Species Information Network

Florina Stanescu
2/26/2019 - 5:48 PM

Thread Opening Text:
This amphibian is native throughout most Europe; however, it is listed as alien for Ireland. Why? Could this be a misinterpretation of the paper by Teacher et al. 2009? Here is the full reference: Teacher, A. G. F., Garner, T. W. J., & Nichols, R. A. (2009). European phylogeography of the common frog (Rana temporaria): routes of postglacial colonization into the British Isles, and evidence for an Irish glacial refugium. Heredity, 102(5), 490.
The conclusions of the study are clear: “Ireland has haplotypes belonging to the western lineage as well as some unique mtDNA sequences that are consistent with survival in an ice-free refugium in Ireland. Thus, a dual colonization of Ireland may have occurred, and contemporary Irish common frog populations may have ancestors both from a refuge within Ireland and from the Western European lineage.”
I strongly suggest Rana temporaria to be excluded from the EASIN database until strong evidence of its introduction outside its range. It could be considered alien, for example, if it was introduced to the Canary Islands.

Riccardo SCALERA
3/1/2019 - 6:13 PM

The species is indicated as introduced in Ireland by many key sources, i.e. (Frost and Darrel 2007, Kraus 2009, see full reference below). However the hypothesis suggested by Teacher et al. (2009) confirms the synthesis made by Marnell (1998): "The origins of the common frog, however,  remain unclear. There is good evidence that it was introduced as recently as the 18th century (Fitter, 1959), and it was probably brought here before that, in the 10th or 11th century, by the Normans for food (Fitter, 1959). These introductions, however, do not exclude the possibility of the frog having been present already". Given the evidence of introductions occurred in recent time and possibly in the past, I suggest to keep the species in the catalogue, but consider the status as cryptogenic.

- Fitter, R. S. R. (1959). The Ark in our midst. London: Collins.
- Frost, Darrel R. 2007. Amphibian Species of the World: an online reference. Version 5.0 (1 February 2007). Electronic Database accessible at http://research.amnh.org/herpetology/amphibia/index.html. American Museum of Natural History, New York, USA.
- Kraus 2009. Alien Reptiles and Amphibians: A Scientific Compendium and Analysis. Springer, [Dordrecht, Netherlands], 563 pp. ).
- Marnell F. 1998. Discriminant analysis of the terrestrial and aquatic habitat determinants of the smooth newt (Triturus vulgaris) and the common frog (Rana temporaria) in Ireland. Journal of Zoology 244: 1-6.

Florina Stanescu
3/2/2019 - 1:03 PM

I do not argue that R. temporaria individuals were introduced from mainland populations to Ireland. I argue the fact that R. temporaria was considered alien to Ireland based on these introductions. Molecular data show that the species was already present there. Therefore, the introductions were not made outside its range.
Please also note that R. temporaria is considered as native species to Ireland by Irish national experts; see for example:
Reid, N., Dingerkus, S. K., Stone, R. E., Pietravalle, S., Kelly, R., Buckley, J., ... & Wilkinson, J. W. (2013). National Frog Survey of Ireland 2010/11. Irish Wildlife Manuals, No. 58. National Parks and Wildlife Service. Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland.

Riccardo SCALERA
3/2/2019 - 1:26 PM

According to Teacher et al. (2009) “Genetically distinct haplotypes occur in populations from the south-west of Ireland. This local genetic differentiation may be a consequence of a local glacial refuge, possibly combined with natural colonization or introduction from Western Europe”. This statement in my understanding implies some uncertainty. Reid et al. (2013) prefer to consider the species as native but do not bring additional evidence of its status. I do not argue the result of Teacher et al. (2009) analysis showing the possibility of native populations occurring in the country, but there is no definitive evidence (like in the case of documented introduction events), hence in my view and consistently with the overall EASIN approach (see EASIN FAQ for details), the species should be considered as cryptogenic.

Florina Stanescu
3/2/2019 - 3:33 PM

I agree. Cryptogenic status can be acceptable until further evidence.

Florina Stanescu
3/28/2019 - 9:49 AM

Thread Closing Text:
Species status to be changed to cryptogenic

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