Talk on invasions at UFRGS

11 May 2018

A talk to the Department of Zoology at Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil

It was a pleasure to address an enthusiastic group of zoologists in their weekly seminar slot. My host, Prof Marcio Borges-Martins, was a post doc at PUCRS when I worked there in 2001. Now he runs a herpetology group at the university with lots of exciting projects. I think my presentation may have just tipped over the hour long allocated slot, but thanks to you all for sticking with it!

Talking to a bunch of Brazilians about South African amphibian diversity is tough, but I hope I convinced them that there's lots of interesting stuff going on at the CIB in Stellenbosch University.

Title: "South African frogs: invaders and invaded."

  aSCR  Frogs  Lab  meetings  Xenopus

Honours students present at Cape Herp Club

02 May 2018

Presentations of Honours Proposals

The honours students present their proposals in a compressed 5 minute format to members of the Cape Herp Club. Meeting since 2004, the Cape Herp Club comprises all academics and students who work on herps in the Cape Town area. 

Speaker 1:  Carla Wagener
Talk title: :  Linking thermal threshold with widely distributed populations of African clawed frogs (Xenopus laevis) over different altitudes
Speaker 2: Damian Van Aswegen
Talk title:  A global assessment of invasive snake impacts using two formal frameworks
Speaker 3: Reesher Kearns
Talk title:  Assessing the change in calling densities of the Cape Peninsula moss frog (Arthroleptella lightfooti) amidst Cape Town’s ongoing drought
After this, I gave a presentation on the MeaseyLab project: "What can YouTube teach us about why people want amphibians as pets?"
All talks were well received and with some great questions and debate. 
  Frogs  Lab  meetings  Xenopus

Frogs, crabs and toe-clipping

25 April 2018

Is clipping toes for DNA samples unnatural?

Procedures involving field sampling of many vertebrates require ethical clearance for ecologists wishing to collect genetic samples for DNA analysis and involve an increasing number of different sampling techniques. A growing number of choices of sampling techniques require researchers to re-examine procedures which have traditionally been accepted without question.

The practice of amphibian toe clipping is controversial. The impact of toe clipping on anurans is likely to differ with their life-history and studies on performance may provide better indications on the effect of clipping different toes. Buccal swabbing provides logistical difficulties and requires more resources for extraction of DNA.

Sampling of tadpoles is likely to introduce bias in the example given for population genetics of anurans, although there may be good reasons for using this technique to acquire genetic material in other circumstances. 

The majority of researchers need to provide sufficient information to convince an institutional ethics committee of their need to conduct ecological sampling. With respect to amphibians, we require more studies on populations using DNA to inform conservation decision making. Toe clipping of adults will represent the best current method for obtaining tissue samples for the majority of studies, as well as providing extra tissue which should be placed into tissue banking facilities for future studies.

One argument against toe-clipping is that it is unnatural. Recently, I found a pond full of frogs and crabs that made me think again about this. 

Show me a population of frogs which have had their mouths naturally buccal swabbed.

  Frogs  Lab  Xenopus

Low to High in South Africa

22 April 2018

From low to high, a search for extreme African clawed frogs

Had a great time in the field at some extreme sites in South Africa with Honours project student, Carla Wagener. 

We started low, trapping in sites within the iSimangaliso Wetland Park. There we were setting traps in shallow muddy pools with warm water, while lots of animals looked on.

Then we got high at the amazing Royal Natal National Park. We climbed up to 3100 m asl, and set traps and searched in the icy river waters. 

Sadly, we only managed to get crabs in our traps, but we found a whole lot of frogs at 2000 m that Carla will use in her project. We'll have to return to the Drakensberg another time to get the highest platannas in South Africa.

Now Carla has to use the frogs to do her experiments. More news on how this progresses here on the blog.

  Frogs  Lab  Xenopus

Theses submission

19 March 2018

Magic March for thesis submission

A big congratulations to Mac and Marike for submitting their theses this March.


Mac’s PhD thesis “Evaluating the effects of changing global climate on amphibian functional groups of southern Africa: an ecophysiology modelling approach” uses performance, morphology, physiology and modelling to predict species distributions in southern Africa.

Marike’s MSc thesis “Acoustic Spatial Capture-Recapture (aSCR) and the Cryptic Cape Peninsula Moss Frog Arthroleptella lightfooti” uses the aSCR technique to determine population density with many acoustic arrays.

Well done to you both! Very fine pieces of work indeed.

  aSCR  Frogs  Lab  Xenopus