A poor documentation of a local extinction: Cape Dwarf Chameleon

Where have all the chameleons gone?

For many years, Cape Dwarf Chameleons were available almost on demand in my garden in Rondebosch. If a visitor wanted to see one, it was seldom more than a few minutes search to find one. They had several favourite spots, which was where I looked first. One of these was a bottlebrush bush which was growing a few metres from the kitchen window. Given that the bottlebrush is an alien plant species, it is a unexpected that generations of chameleons would select the sane plant. But obviously, the bottlebrush must had attracted a good supply of insects, as chameleon food. So close-up views of chameleons during breakfast and washing up dishes was part of normal everyday life. This blog attempts to use the data in the ReptileMAP section of the Virtual Museum to describe how Cape Dwarf Chameleons went from common to locally extinct in the garden.

 

Overall, Cape Dwarf Chameleons have a tiny range, just the southwestern corner of the Western Cape. They are classified as “Near Threatened” by the IUCN.

The Cape Dwarf Chameleon occurs in only 16 quarter degree grid cells at the southwestern tip of Africa. There is a total of 221 records in the Virtual Museum.

It seems that my first digital image of a Cape Dwarf Chameleon was an attempt to frustrate audiences. It was taken on 27 August 2006. It was regularly used in PowerPoint presentations, especially as the slide before the title, with the instruction, find the reptile on the screen. Now you need to find it on your screen!

Can you find the chameleon? The camouflage is excellent. It is in the ReptileMAP section of the Virtual Museum at http://vmus.adu.org.za/?vm=ReptileMAP-8085.

Here is a zoomed in version, in which it is easy to see the chameleon, but you still need to find where this is in the photo above.

Now you can see the chameleon easily, but find where this fits into the photo above is still a bit of a challenge.

 

It next time I took a digital image of a chameleon was, a few months later, on 25 November 2006. It was doing the totally daft thing of doing a tightrope walk along the washing line.

Cape Dwarf Chameleon practicing the tightrope on the washing line. In ReptileMAP,  it is here: http://vmus.adu.org.za/?vm=ReptileMAP-169051.

 

Don’t look down!

 

This is the first of many records of successive generations of Cape Dwarf Chameleons which used this bottlebrush bush. Curated at http://vmus.adu.org.za/?vm=ReptileMAP-7406.

It seems that I took no photos of chameleons from 2006 to 2012, because there are none uploaded to ReptileMAP. There were simply chameleons almost continuously in the garden. At the time, it seemed pointless recording them. The photos that I got were used to illustrate camouflage and to document the tightrope stunt!

A sobering event took place near the end of 2012. My PhD student, Elsa Bussiere, was distracted by a continuous clicking sound that was persisting for hours and hours. Investigating, she found that a chameleon was short-circuiting two of the wires of an electric fence which had recently been erected by a neighbour. The chameleon was dead.

This Cape Dwarf Chameleon was electrocuted when it tried to make the move between gardens. This record is curated at http://vmus.adu.org.za/?vm=ReptileMAP-7986.

After this, I started uploading the bottlebrush chameleons regularly, until I was doing this every time I saw them. There are five records in 2013. six in 2014, three in 2015, and two in 2016, on 28 September, and on 31 October. And those two records in 2016 were the last two records of Cape Dwarf Chameleon in my garden. This is now more than two years ago, more than double the largest gap in any previous pair of records

This beautifully marked Cape Dwarf Chameleon was recorded in the bottlebrush more than two years ago. Sadly, this was more than two years ago, and the species now seems to be locally extinct. This photo was taken by Andreas Ionnides, and uploaded to the Virtual Museum as http://vmus.adu.org.za/?vm=ReptileMAP-159467.

It seems likely that the Cape Dwarf Chameleon is now extinct in my garden, and this is probably true of the neighbourhood. The proliferation of electric fences took place at during the period the chameleon disappeared, and this is almost certainly a key factor.

Another factor is getting flattened on roads.

A big wheel has flattened this three-dimensional chameleon into a two-dimensional chameleon. Roads take a large toll on biodiversity. Most visibly it is reptiles (and especially snakes), birds and mammals that become road kills. This incident was documented by Bukola Braimoh and Joshua Azaki in Observatory on 24 December 2017. It is never pleasant to take photographs like these, but they incredibly important and valuable as evidence of cause of death. This record is curated at http://vmus.adu.org.za/?vm=ReptileMAP-164297.

From 2012 onwards, data collection can almost be described as consistent, but it is certainly not good enough for a scientific paper. The weakest part of this account is the lack of solid evidence that Cape Dwarf Chameleons really were common in the garden until about 2012. We do not know what species is next going to be impacted. So the best advice to give citizen scientists is to set themselves the target of “refreshing” the occurrence of even the common species in their patches at regular intervals. Quarterly feels about right, but there are no hard and fast rules as yet.

 

Les Underhill
Les Underhill
Prof Les Underhill has been Director of the Animal Demography Unit (ADU) at the University of Cape Town since it started in 1991. Although citizen science in biology is Les’s passion, his academic background is in mathematical statistics. He was awarded his PhD in abstract multivariate analyses in 1973 at UCT and what he likes to say about his PhD is that he solved a problem that no one has ever had. He soon grasped that this was not the field to which he wanted to devote his life, so he retrained himself as an applied statistician, solving real-world problems.