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Dan defends his MSc thesis

08 February 2023

Ghost frogs are under threat from invasive fish - it's official

Dan van Blerk defended his MSc thesis today in what is likely one of the most anticipated events of 2023. Dan has been working for the last 2 years on getting enough data from as many streams as possible to establish whether or not invasive fish (most notably bass and trout) are impacting tadpoles of ghost frogs. The data were unambiguous. Invasive fish are having a major impact on the density of ghost frog tadpoles.

Having this unambiguous data is really good news. It is all very well to speculate that the invasive fish impact tadpoles, and there are a couple of annecdotal studies that show the same. But getting robust data from lots of sites on lots of rivers is no easy job. Dan worked tirelessly, trudging up and down some of the most beautiful scenery in South Africa's fynbos, to collect the necessary data. In truth, Dan greatly enjoyed his time in the field. It did give him a great excuse to play in water and catch fish - two of his most enjoyable pursuits.

Below one of Dan's pics shows the upper portion of a stream beyond which fish cannot reach, and the tadpoles are safe!

His work is critical to conservation managers who require evidence in order to base their conservation management decisions.

We look forward to seeing Dan's work in print shortly!

Read more:

van Blerk, D. (2023) The Impacts of Invasive Fish on Ghost Frog tadpoles. MSc thesis, Stellenbosch University.

  Frogs  Lab  meetings

Hybrid CIB ARM for 2022

24 November 2022

The CIB holds its final ARM as a hybrid event

Every year the CIB holds an Annual Research Meeting as an opportunity for students to present their work to an audience of peers and the CIB network of Core Team Members, affiliates and associates. This year sees the last meeting in the role of the CIB under the DSI-NRF Centre of Excellence. The 2020 and 2021 events were both online affairs. 

Three MeaseyLab students presented their research findings at the meeting:

Laurie Araspin started the show by presenting a chapter from her PhD work on "Locomotor performance in Xenopus laevis" Laurie is a co-tutelle student with Anthony Herrel's MECADEV lab at the Natural History Museum in Paris.

Next Dan van Blerk presented a chapter of his MSc work on "The impact of invasive fish on ghost frog tadpoles", work that he conducted in collaboration with Josie Pegg from SAIAB. 

Lastly, Jonathan Bell presented some preliminary results from his MSc work on "Optimising conditions for controlling the invasive guttural toad". Jonathan is conducting his MSc at the CIB, but also works full time for the City of Cape Town invasive species unit.

Congratulations go to Laurie and Dan, both of whom won runners up prizes in their categories for best presentation.

Dan presents at the Conservation Symposium

02 November 2022

Dan van Blerk presents his research findings at the Conservation Symposium

You might remember last November that the MeaseyLab took part in the Conservation Symposium (see Blog post here). In 2022, the event was hybrid and Dan van Blerk decided that he'd travel up to KZN to present his research in person.

Because it was a hybrid event, Dan could be seen in person, but was also seen by everyone attending online.

The talk was also recorded and is available here for you to watch on the Conservation Symposium YouTube Channel.

Well done Dan!

van Blerk, D., Pegg, J. & Measey, J. (2022) Impacts of invasive fish on ghost frog tadpoles. Conservation Symposium. Scottburgh, KwaZulu-Natal. 30 October to 5 November 2022 

  Frogs  Lab  meetings

Having fun at the 21st European Congress of Herpetology

08 September 2022

Great to see Xenopus people meeting at the 21st European Congress of Herpetology

This year's European Congress of Herpetology is being held in Belgrade, and there were lots of Xenopus talks!

From left to right: Felix Deiß, Anastasia Regnet, Dennis Rödder, Nicholas Wei Cheng Tan, Natasha Kruger and Philipp Ginal

Among these were Dr Natasha Kruger presenting work from her PhD on a Xenopusreciprocal exchange experiment with tadpoles:

Kruger, N., Secondi, J., du Preez, L., Herrel, A. & Measey, J. (2022) Is there no place like home? Response of African Clawed frog tadpoles to novel environments

 and Philipp Ginal talking about his recent work on modelling the difference between adult and tadpole time in Europe:

Ginal, P., N. Kruger, L. Araspin, M. Mokhatla, J. Secondi, A. Herrel, J. Measey & D. Rödder (2022) More time for aliens? Performance shifts lead to increased activity time budgets propelling invasion success. 

I'm happy to say that both papers are in press, and you can read them here (even if you didn't see the presentations!).

  Lab  meetings  Xenopus

EU lists African clawed frogs as invasive species of concern

18 July 2022

Xenopus laevis gets listed by the EU as an invasive alien species of Union concern

Back in October 2018, I was invited to Brussels to referee the impact assessment for African clawed frogs by Riccardo Scalera and various contributors (see blog posthere). At this point, the assessment had already been going on for some time. 

This month, I was back in Brussels for another meeting (Conference on the management of vertebrate invasive alien species of Union concern). An announcement during that meeting was that the EU was about to sign a document stating that the species being reviewed in 2018 were about to come into effect. Thus, on 15 July 2022, Ursula Von der Leyen signed in an update to the list of invasive alien species of Union concern, includingXenopus laevis(seehere). This list will come into effect later in August, and in particular for the African clawed frog, research institutions are being allowed extra time to issue permits before their listing takes effect.

This is really exciting news. In the ~40 years sinceX. laevishas been invading France (and longer in the UK - although these regulations won’t affect the UK directly), many people refused to believe that this species had any significant impact. I remember contacting co-ordinators ofDAISIE(Delivering Alien Invasive Species Inventories for Europe), and being told that they had no interest. Similarly, despite my best efforts the ISSG refused to update their pages onX. laeviswith important evidence of impacts. So what tipped the balance?

The funding ofINVAXEN, and later theLIFE project CROAAwere both funded by the EU and provided plenty of extra evidence thatX. laeviswas an impacting invasive species. Once the EU had invested in the research, they were more interested in looking more closely. Now, some 4 years after the meeting in Brussels, we finally see that the EU is serious about this species. It is worth remembering that the procedure takes a lot of time for a reason, there is a process to be followed with plenty of steps (see below). Also within this period, at least two more invasions in the EU have occurred (Bordeaux and Lille) and the latter appears to be spreading.

It’s taken a long time, and there are plenty of people who have played an important role in getting the African clawed frog listed. I hope that this now means the species will no longer be available for sale as a pet (i.e. end of trade) and that EU member states will take extra measures when new populations are found.

Process followed to list species an invasive alien species of Union concern

  • European Commission or Member State propose a risk assessment + evidence that criteria for listing are met.
  • Drafts are public and open to comments (within deadline).
  • Scientific Forum checks scientific robustness of draft risk assessments: are they fit for purpose?
  • IAS Committee checks IAS for compliance with criteria listing (meetings in 2021). Commission internal consultation
  • Notification to WTO: notified on 27 October 2021, 60 days - No comments received
  • Public feedback: 5 weeks, 16 November - 14 December 2021. 43 comments received
  • IAS Committee checks IAS for compliance with criteria listing and votes (meeting 2022)
  • Submission for adoption by Commission (written procedure) - 12 July
  • Publication in OJ 
  • Entry into force - 20 days after publication (mid-August 2022)

  Frogs  Lab  meetings  Xenopus
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