Sunday 27 December 2020

Publication: Tortoise mortality along fence lines in the Karoo, Journal of Nature Conservation


From experience, electric fencing burns are very painful: but of course, we can move away fast and get away from the pain!

But imagine getting shocked again and again for hours and hours. It was 2013 when I first recorded dead tortoises on an electric fence on a bird survey route north of the Baviaanskloof. Since then, I’ve seen hundreds more as electric fencing has become a dominant predator control strategy across South Africa. Tortoises, once shocked, withdraw to the safety of their shell and hope it stops. It never does… they endure pulse after pulse of current until they die. It is inconceivable to me that there are no controls on this infrastructure that take this into account: there are simple solutions that will allow the use of these fences without killing tortoises.

Fences require daily patrolling to remove tortoises. Alternatives could include thermostatic switches which turn off fences when tortoises are most active, or programmed ‘escape’ periods. These solutions are offered with the realisation that electric fences are not going away: they are too valuable for the control of predators or for restricting the movement of big game (SANParks have major electric fence infrastructure on many of their parks). 

Dead leopard tortoises on electric fences are an obvious problem. What this research also showed was the standard mesh fencing is bad for the smaller tortoise species (most of the species), which get wedged and stuck. This fence type is prolific across the rangelands of southern Africa. All of this is not good news for the world’s tortoise hotspot.

This is a situation that makes me feel sad and powerless: all I could do as a scientist was help document this tragedy. My effort to draw attention to the problem by making a YouTube video has had all of 150 views in 4 years. So: there we go, I offer the world another piece of sad information and hope those with the power to make change (which should be all of us) will act upon this.

I’m very grateful to Matt Macray, Conservation Biology MSc student at the Fitz, for doing the groundwork on this; as well as to Biosphere Expeditions for their support. I was able to facilitate this work through a postdoctoral research grant through SANBI: thanks to Phoebe Barnard for that. I’m grateful to Professor Graham Alexander, Wits University, for his collaboration and herpetological expertise. And lastly, I always thought my first co-authored paper with Professor Peter Ryan would be about birds: but life can be funny like that.

https://www.sciencedirect.com/science/article/pii/S1617138120301916

The paper is free to view until February 2021, and I'm happy to provide a copy on request. Elsevier, the publishing house, were very fast and efficient in getting this article online after acceptance.  




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