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

OTS back at Cape Point

04 March 2018

Great to join OTS at Cape of Good Hope

Another opportunity to monitor the Cape platanna (Xenopus gilli) at the Cape of Good Hope section of Table Mountain National Park. This time with a great crew from Organisation for Tropical Studies (OTS). I was last with OTS in October (see here), and before that in February and see blog entry herehere and here!

This time we had a delayed start as part of CoGH burned down on Thursday (1st May), but the area across link road and Olifantsbos didn't include our frogging patch (more's the pity). 

The focus was on the drought, with GEPS dam as low as I've ever seen it, but still with hundreds of frogs inside.

  Frogs  Xenopus

INVAXEN informs EU policy

15 December 2017

How does research get translated into policy?

Work on invasive Xenopus laevis by a consortium of labs in Belgium, France, Germany, Portugal and South Africa has produced research that helped to brief European policy makers.

“According to our research, climate change could increase invasion risk of predatory frogs such as the African clawed frogs. Areas in France and the UK are particularly vulnerable to invasions because of their increasing suitability as a habitat with warming temperatures. This situation requires priority setting and better anticipation of future invasions.” Anthony Herrel, coordinator for the BiodivERsA-funded project INVAXEN.

The policy brief above features the MeaseyLab publication: Frog eat frog.

  Frogs  Xenopus