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Table Mountain Ghost Frogs need cold water

11 August 2020

New study looks at requirements for Table Mountain Ghost Frog tadpoles

In a new study, published today by MeaseyLab alumnus Zishan Ebrahim and colleagues, they determined the requirements of the tadpoles of Table Mountain Ghost Frogs, Heleophryne rosei. The iconic Table Mountain Ghost Frog only lives in the streams and kloofs around Table Mountain and nowhere else on the Cape peninsula (or anywhere else in the world). Previously, researchers had determined that the tadpoles require perennial flow (streams that don't dry) in order for the tadpoles to inhabit them. This then is the reason why Table Mountain is the only massif on the peninsula with the frogs. However, in a paper published today, Zishan Ebrahim shows that the frogs also have a sweet spot of temperatures above (and presumably below) which they can't tolerate. 

Zishan monitored physical parameters of Table Mountain's stream water for many years finding that tadpoles don't inhabit all of the streams with perennial flow on the mountain. The warm water that flows down some of the streams could be influenced by the complex hydrological installations on top of the mountain that were originally installed to supply fresh water for the city. Now much of the water on top of the mountain sits in dams where it heats in the sun and may influence the temperature in the streams. There are other problems on Table Mountain, most notably invasive trees, that are also likely to change the hydrological properties of the water and impact on the Ghost frogs and their tadpoles. 

Read more about the conservation relevance of this work in this recently published paper:

Ebrahim, Z, de Villiers, A. and Measey, J (2020) Assessing water conditions conducive to tadpoles of the Table Mountain Ghost Frog (Heleophryne rosei) and the relevance to their conservation Koedoe Vol 62 (1): a1581 DOI: https://doi.org/10.4102/koedoe.v62i1.1581 

  Frogs  Lab

Prize winning Jenicca

26 June 2020

A big congratulations to Jenicca Poongavanan who won best poster at the first virtual International Statistical Ecology Conference 2020

Some of you may remember that Jenicca did her MSc with Res Altwegg, Ian Durbach and myself in SEEC at UCT. Jenicca used aSCR (generated by Marike Louw) to investigate the spatial distribution of densities of the Peninsula Moss Frog, Arthroleptella lightfootii.  To read more about Jenicca's thesis, and aSCR in general see here and here. Jenicca has since moved to a lab in Florida where she now studies sea-birds (see here).

Poongavanan, J., Altwegg, R., Durbach, I. Measey, J. 2020 Modelling the range-wide density patterns of the Arthroleptella Lightfooti using acoustic monitoring data. (Poster) International Statistical Ecology Conference  (virtual): June 22-26, 2020.

  aSCR  Frogs  Lab  meetings  prizes

Changing their behaviour

15 June 2020

Behaviour change and a hormonal link

Who could forget the fantastic visit or Carla Madelaire and Adriana Barsotti to the MeaseyLab back in January 2019 (see here)? The two spent only a few months in the lab, but worked super hard on a few experiments that drilled down into the relationship between hormones and behaviour of guttural toads when they are dehydrated.

Today sees the beginnings of all the fruit of their labors with the publishing of Carla's behavioural paper in Behavioral Ecology and Sociobiology!

This paper represents a significant step forwards as we show that after only 20 years of invasion into the dry conditions of Cape Town, Guttural Toads have changed the way that they think about water. When you find it, you stick with it! In this paper, Carla shows a link between this water finding behaviour and the hormone corticosterone. Adriana has another manuscript (submitted) that further investigates this phenomenon also with Guttural Toads. 

It was a great pleasure working with both of you and we look forward to more work and celebrations in the future (there will be cake & cachaça!). Last January, we celebrated their arrival (see here).

The intrepid duo catching toads in Durban with the all important yoghurt pot!

To read more about Carla and Adriana and their adventures in South Africa, see blog posts here, here, and back in Brazil here.

Madelaire, C.B., Barsotti, A.M.G., Wagener, C., Sugano, Y., Baxter-Gilbert, J., Gomes, F.R., Measey, J. (in press) Challenges of dehydration result in a behavioral shift in invasive toads. Behavioral Ecology and Sociobiology    https://doi.org/10.1007/s00265-020-02866-5 pdf


Publicity for Biological Invasions in South Africa

05 June 2020

Publicity for our new book: Biological Invasions in South Africa

Today is Environment Day, and to celebrate, Brian van Wilgen has been given interviews to journalists about our new book: Biological Invasions in South Africa. Since the book was released free online in March (see blogpost here), the chapters have been downloaded 154 thousand times! 

Some of the great information shared in this book is about alien trees that consume ~5% of our scarce water resources, in South Africa. Invasive species pose a direct threat to the survival of almost half of 1 600 native species listed in South Africa’s Red Data List. The book provides information on 1 422 alien species including plants, birds, mammals, fish, reptiles & amphibians. 

A newpaper article in the Witness:

You can listen to Brian's interview on this podcast or this radio interview.


INVAXEN video now out

27 May 2020

BiodivERsA has officially released the INVAXEN video

Yes, it's the moment that you've been waiting for so long. The INVAXEN video was the result of winning a competition to publicise the outcome of the project. The output was a collaboration between INVAXEN researchers, BiodivERsA and the company Squarefish. It was quite illuminating to see the process of the script, storyboard, animation and then hiring the voice-over and music. 

Here's the finished product:

And the blurb underneath:

This animated movie shows the results of the INVAXEN project (“INVAsive biology of XENopus laevis in Europe”) which studied the biology, ecology, and impact of the highly invasive African clawed frog (Xenopus laevis). The scientists developed models to predict future invasion patterns and passed on their scientific findings to local stakeholders to collaborate with them on conservation actions. The video shows how BiodivERsA-funded projects not only excel in their scientific research, but also how relevant they are at societal level, and how they can help with management practices on the field. ~ This research was funded by the ERA-Net BiodivERsA, with the national funders ANR (France), BelSPO (Belgium), DFG (Germany), FCT (Portugal), part of the 2012-13 joint call for research proposals on invasive species and biological invasions. The Belgian Biodiversity Platform & BiodivERsA led the production of this video, along with the INVAXEN researchers and the animation & motion design studio Squarefish.

  Frogs  Lab  Xenopus
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