The Golden Treasure Buried Beneath Kruger's Soil
By Melissa Wray
In Kruger National Park
Unseen, unheard and generally unnoticed, burrowing below the soils of the Kruger National Park is a golden treasure - Juliana's golden mole. Listed as the third most endangered mammal in South Africa, Juliana's golden mole has only been found in three places in South Africa, one of which is the Kruger National Park.
There are five golden mole species listed in the top 10 most Critically Endangered mammals of South Africa. Altogether there are 21 species of golden mole, all of which occur in sub-Saharan Africa, and many of which are only found in South Africa. Two thirds of the species are endangered, but very little is known about their biology and ecology.
This alarming situation means that conservation planning is required, but a better understanding of the animal's ecological requirements is needed first. Craig Jackson, a master's student at the University of Pretoria, has taken on the often difficult task of finding out more about the tiny tunneler.
Together with other researchers at the university, and funded by the World Wide Fund for Nature (WWF), he is trying to find out more about Juliana's golden mole by conducting fieldwork in areas where it was his torically known to occur - Bronberg Ridge in Pretoria, Nyslvley Nature Reserve and south western Kruger.
There is, however, some question as to whether the Kruger population is the same species as that found in the other two locations. Some preliminary genetic work, coupled with KNP golden moles having an extra molar in their dental structure, suggests that they may be a new species that is more closely related to Gunning's golden mole, which is found near Magoebaskloof.
Weighing in at only 50 grams, Juliana's golden moles have torpedo shaped bodies and are extremely well adapted to their underground life. They do not have eyes or ears on the outside of their bodies, and are covered in fur with a golden sheen to it. Their front legs have been modified into pick-like claws, and they have a leathery nose for pushing through the soil. The small insect-eating animals have a ferocious appetite when they are active, fuelling a high metabolic rate.
However, during the day golden moles enter a state of torpor, when their body temperature and heart rate is lowered, lowering their metabolic rate. This is essentially a daily bout of hibernation. The distribution of golden moles is restricted as they can only tunnel through soft soils, usually sandy or sandy loams. They can not cross obstacles that interrupt their habitat, such as tar roads. If an artificial feature cuts across their habitat, it will fragment a population, which will eventually result in inbreeding and extinction.
Golden moles should not be confused with mole-rats, which also construct burrows underground, but eat plants, have eyes and push up mounds of soil. Mole-rats are related to rats, while moles are more closely related to shrews. Given their small size and nocturnal move ments, it is not surprising that in 50 years only eight records of golden mole activity has been found in Kruger.
Craig has begun field work in the park, where his trained eye can detect the small ridges left on the surface of the soil after the mole has conducted its nightly hunt for succulent earthworms, beetle larvae or grasshoppers. All previous reports had come from the south-western part of the park, so Craig spent many days walking along transects, straight lines that cross different sandy soil types with different properties, in order to find the small mole trails.
After walking about 40 kilometres of transects, he was able to locate several tunnel systems. Research will focus on these tunnel systems, determining exactly what type of soils are utilised by the moles and the specific type of plants that grow there. For example, Terminalia sericea, the silver cluster leaf or Vaalboom, often grows in the sandy soils where Juliana's golden mole might be found.
This will give the scientists a good idea of the type of habitat that is specifically associated with these shy creatures. Using this, more potentially suitable habitat can be found from existing geographical data to high light areas of high conservation importance. Further work on these cryptic animals is planned, but the work is weather depend ent. In the dry wintertime the moles are generally not very active.
They forage mostly in summer months after good rainfall, but if heavy rains fall it can wipe out the characteristic tunnels that Craig relies on to find the moles. Craig is also hoping to trap some moles in order to get samples for DNA analysis at the University of Pretoria. This may be able to determine if all three populations of Juliana's are the same species. He hopes to be able to fit some of the moles with the latest in tracking technology: tiny radio tags that weigh only three grams and last for up to six weeks.
Once equipped with a radio tag, Craig can release the moles back into their tunnel sys tem and get an idea of how the mole moves about during the day and the night, how big their home range is, when they are most active and what triggers their daily hibernation mode. The Kruger Park is also home to another species of golden mole. Juliana's golden mole is restricted to the sandy soils found in a narrow belt on the Park's western boundary in the Pretoriuskop region.
Another type of sandveld is found on the Mozambican border, north of Shingwedzi and east of Punda Maria, and here the yellow golden mole is found. This has a wider range than Juliana's and is also found in Mozambique, Maputoland and Tembe Elephant Park. As Craig puts it, 'With so many of the golden mole species losing habitat at an alarming rate, those within the Kruger Park's boundaries are certainly amongst the saf est, and at least for these species there is a light at the end of the tunnel.'