Researchers look to shed more light on the elusive riverine rabbit

by CapeNature

According to the Zoological Society of London, the riverine rabbit (Bunolagus monticularis) represents one of the top ten Evolutionarily Distinct and Globally Endangered (EDGE) mammal species in the world. Currently listed as Critically Endangered their futures are inextricably linked to the farmers of the Karoo on whose land most of the remaining rabbits occur.

The challenge for biologists is as simple as it is frustrating: How does one find and then study a rare small animal in the vastness of the Karoo? Detecting them using systematic methods is simply not cost effective. Consequently, most new sightings have been opportunistic encounters with Karoo residents and, regrettably, their vehicles.

Once located, studying these elusive animals has proven equally challenging and consequently little is known about either the ecological or biological factors that explain their patchy presence. It is here that advances in remote monitoring with the use of motion triggered camera traps have helped break new ground.

Zoë Woodgate, a PhD candidate in the Institute for Communities and Wildlife in Africa (iCWild) at UCT, has been using camera traps to monitor riverine rabbits in the few locations where they are known to occur. Her project, which is funded by the Endangered Wildlife Trust (EWT), the South African National Biodiversity Institute (SANBI) and UCT’s iCWild, is a collaborative venture seeking technological solutions to an old problem.

Work started in Sanbona Wildlife Reserve, one of newest confirmed localities of the riverine rabbit in the Western Cape. To understand where they might occur in the reserve Zoë deployed over 140 camera traps across its length and breadth. Despite recording 57 unique species and taking 15 312 photographs of wildlife, 240 of which were lagomorphs (members of the rabbit/hare family) – no riverine rabbits were photographed.

Camera trap photograph of a leopard at Sanbona Wildlife Reserve

Undaunted Zoë adapted her camera trap sampling protocol from a regular grid of camera traps to a clustered approach, targeting areas where the rabbits had previously been sighted. This design not only yielded 60 photographs of riverine rabbits but provided data on both their likely competitors and predators, in addition to clues about what habitat they prefer.

Surprisingly, the riverine rabbits at Sanbona are not riverine, with the most photographs recorded on an open plateau that had been ploughed more than 14 years previously. An analysis of whether rabbit presence could be explained by what other animals were present (or absent) revealed an even more intriguing result. The absence of the common hare was the best single predictor of rabbit presence!

camera trap photograph of a riverine rabbit

These results raised two intriguing questions. Could it be that competitive exclusion by the common hare explains why the rabbits are rare? Have we been looking in the wrong areas (i.e. rivers), and are rabbits persisting in degraded land because it is unsuitable for hares?

Clearly we need to expand the study to test the generalities of these unexpected results from Sanbona. First on the list of new study sites is the Anysberg Nature Reserve, where riverine rabbits were last seen in 2014. The camera traps are already in the field quietly spying on all who cross their paths and will soon confirm whether the rabbits are still present and, if so, how this relates to land use and competitors.

Humans may well be the drivers of the currently accelerating extinction rates of wildlife. However, we are also great innovators and capable of designing and deploying innovative technologies for understanding not only how we broke systems but how to fix them. Zoë’s research with camera traps is breaking new ground in explaining what might have been broken, which is the first part of knowing what to fix.

If you are lucky enough to spot what may be a riverine rabbit, please record a GPS location, the time of the sighting and, if possible, a photograph or video of the animal. If you’d like to discuss the riverine rabbit with like-minded individuals, then contact the Institute for Communities and Wildlife in Africa (ICWild) and the Endangered Wildlife Trust (EWT) on their respective Facebook pages here and here.

Please report sightings to either ICWild and EWT, as well as Zoe Woodgate on zwoodgate@outlook.com

Write a Reply