Conservation

DIAMOND BIRDING ROUTE

The Diamond Birding Route is one of many manifestations of the passion that De Beers and the Oppenheimer family have for South Africa's environmental conversation. The route, which is a partnership project between De Beers, E Oppenheimer & Son and BirdLife South Africa, provides guided public access to the properties owned by the companies for bird watching, education and research. It also raises awareness and understanding among local communities about the role of the environment as a source of livelihood.

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BUTTERFLIES AT TSWALU KALAHARI RESERVE

Three things make the butterflies of Tswalu Kalahari exceptionally interesting. There is no existing inventory of butterflies at Tswalu and secondly, the wide range of habitats with the intrusion of the Korannaberg along the eastern side of Tswalu, provides the possibility for the occurrence of some unusual finds. And lastly, during times of plenty, butterflies are abundant – and the impact of the caterpillars on the vegetation of chosen food plants at Tswalu must be considerable.

Life is short for butterflies. Even the large butterflies may live for perhaps two months and small ones for a few days. And so adult butterflies time their emergence from their dormant pupal stages precisely, to coincide with the rainy season which provides optimal conditions for breeding. Adult butterflies require nectar from flowers, whilst the caterpillars that hatch from eggs need fresh growth from host plants. The pupa is the life stage that can wait out the adverse times.

Unpredictable and variable, that describes the Kalahari rainy season. But this is when the butterflies emerge in abundance. And so it was that our visit to Tswalu Kalahari was undertaken once we knew that rain had fallen. Butterflies love heat, and so it was that our efforts centred on the hottest part of the day.

Prior to the expedition, we had drawn up a list of about 100 species based on macro-scale distribution patterns. A one-off trip of just a few days inevitably will locate a far smaller number than that, and it will require many trips over a period of time to make a complete inventory. However, we succeeded in capturing and identifying a highly respectable total of 38 species at 13 localities, several of which were visited more than once. The greatest diversity was found in the savanna-treed gorges penetrating the Korannaberg. We did not expect or find many butterflies in the open Kalahari dunes, even after the rains, as the macro distributions show few widely distributed species over the vastness of this area.

The waterholes were a magnet for the butterflies, being found in large numbers drinking from the damp rims. Sometimes we found many butterflies, especially Grass Jewels, clustered thickly on the fresh faeces of various mammals, from which they reportedly draw minerals. Gardens, with permanent water and richer vegetation than the surrounding area, were also a place where we located three species not found elsewhere at Tswalu.

Wherever we went, the white butterflies occurred in vast numbers. These were mainly Brown-veined White, include many mating pairs. This species disperses from north-western South Africa all over South Africa in migrations across fronts of hundreds of kilometres at times. Amongst the white butterflies were five Colotis species – the Queen Purple-tip, Speckled Sulphur Tip, Banded Gold-tip, Lemon Traveller and Common Orange-Tip. At the top of the Korannaberg, we found many Patricia Blues as well as a White Cloaked Skipper. We searched hard for Coppers, which are often specific to mountain ranges, and located the Damara Copper on several occasions, but nothing unusual. Well at least not yet! And widespread common species included the African Monarch, Zebra White, Yellow Pansy, Painted Lady and Citrus Swallowtail.

Of great interest is the fact that white-trunked Shepherds Tree Boscia albitrunca is a food plant for many of Tswalu’s butterfly species, including the Brown-veined Whites.

There is much to follow in unveiling the butterflies of Tswalu.

BLACK RHINO RESEARCH AT TSWALU KALAHARI RESERVE OCTOBER 2003 - 2006

Black rhinos were decimated throughout Africa from an estimated total population of 100 000 during the late 1960's to fewer than 2,410 in 1995.  This staggering decline of more than 97% in just 30 years is the fastest recorded loss of any mammal species.  Since 1996, black rhino numbers have stabilized and started to rise due to increased security and biological management of remaining animals and at last count numbers had reached 3,600.  However, there is clearly still no room for complacency.

In June 1995 eight rhinos arrived at Tswalu from Etosha National Park in Namibia and were released in the Korannaberg area.  Today the black rhino population on Tswalu stands at 19 with two calves born so far in 2004 and other expected in October.  These desert dwelling rhino belong to arid sub-species, Diceros bicornis bicornis, which is identified as being critically endangered by the South African IUCN Red Data book listing.

HOW MANY RHINOS?

In 2003 Tswalu invited PhD student Jo Shaw to study the ecology of black rhinos on Tswalu to determine how many rhinos the reserve could support.  The number of animals that can live in an area is determined by the amount of different plant species for them to eat throughout the year which is in turn dependent upon the amount of rainfall.  In an arid environment like Tswalu, where rainfall is scarce and unpredictable, food availability varies considerably both throughout the year and between years.  This makes it difficult to estimate the number of rhinos that the reserve can carry.  The time of year which is the most difficult for the rhinos is the end of the dry season.  Most of the plants have lost all their leaves and only a few species are then eaten.  It is the number of these plants that are eaten at this critical time that ultimately controls the number of rhinos.

This research aims to determine what the rhinos are eating throughout the year.  The red Kalahari sand clearly retains each footprint, making it possible to follow exactly a rhino's movements over the previous hours and even days.  Each rhino has a different pattern of heel cracks making it possible for Tswalu's experienced game scouts to know which individual they are following from their footprints.  Black rhinos use their prehensile upper lips to manipulate branches into their mouths and the distinctive diagonal cut left on the branch makes it possible to count the number of bites that they have taken from each plant.

This information will be used to build a computer model to compare the amount of energy available from plants at different times of year and the amount of energy a rhino needs.  This model will not benefit Tswalu by providing information on their habitat capacity but can be adapted as a tool for black rhino management throughout Africa.

WHAT WE DO...

At first light we drive around all the waterholes in the rhino area, checking for rhino tracks left the previous night. This research is focused on the five adult female rhino on Tswalu, shy Inyani who runs at the merest hint of us, calm Kagale who happily poses for photographs, beautiful Nantoni with her huge horns, temperamental Usuk who surprises us every time and Bogale, infamous for charging vehicles.

Once we have detected fresh spoor we drive the roads around the area to locate the rhino's whereabouts and get out to follow the tracks.  I still think that tracking black rhino on foot is one of life's greatest thrills.  Carefully placing each step to avoid making too much noise and constantly checking the wind direction - ears pricked for a warning snort or crashing of branches and eyes straining to make out a solid grey shape in the bushes ahead.

As the sun and temperature rise and the shadows shorten we know that is increasingly likely that the rhino and calf we are looking for will have sought sanctuary from the searing heat in the shade of a tree. We walk with extra care to avoid bumping into one of these sleeping beauties.  When we find them we cautiously move closer for a clearer view and identify the rhino using their unique ear notches.  We check their body condition before creeping away quietly, hoping to leave them undisturbed.  Black rhinos live in a different world to us with notoriously poor eyesight, but an acute sense of smell and hearing.  When the wind direction is right it is possible to stand quietly and watch them undetected.  However, should they hear or smell us they usually turn and run away - reports of their aggression seem exaggerated....

JOIN US

You too can experience the incredible thrill of tracking black rhinos and come face to face with one of these amazing creatures!

If you would like to join us in our search for the rhinos, please tell your field guide and if possible they will arrange for you to accompany us.

JO SHAW
Jo comes from Lincolnshire in the UK and completed her undergraduate studies in B.Sc. (Hons) Zoology at Kings College, University of London.  After graduating she spent 3 years working for Save the Rhone International, a charity raising funds and awareness for the rhino conservation.  In 2002 Jo graduated from the University of Cape Town with distinction in M.Sc. Conservation Biology for her research into the use of spoor counts for monitoring desert dwelling black rhino in the Kunene Region in Namibia.

Jo is now working with Prof. Norman Owen-Smith, Director of the Centre for African Ecology at the University of the Witwatersrand in Johannesburg on her PhD in black rhino ecology at Tswalu Kalahari Reserve.

This work is funded by Tswalu Kalahari Reserve and Save the Rhino International.

DAMARALAND MOLE-RAT RESEARCH AT TSWALU KALAHARI RESERVE

In cooperative animal societies, such as those of the ants and bees, only dominant group members breed and a host of non-breeding workers help to rear their offspring. Darwin recognized that the altruism of these workers posed a problem for his theory of natural selection, which was thought to favour only selfish behaviours.  As a result, biologists have been fascinated for generations by the challenge of understanding how these bizarre societies have evolved in so many animal groups (e.g. African wild-dogs, fairy-wrens, cichlid fish, leafcutter ants, meerkats and Damaraland more-rats).

The African mole-rats show the full range of social complexity from solitary species to species with complex co-operative societies (where sterile workers help to rear the queen's young).  Comparing all of the species reveled that only the two cooperative species lived in very dry regions (naked mole-rats and Damaraland mole-rats).  This led to the idea that cooperative societies may have evolved in these species, because only by living in large cooperative groups are they able to find enough food in such a challenging environment.  However, no study has investigated whether the cooperative mole-rats do actually benefit from group-living in this way, and until this is done, the reasons for the evolution of their unusual way of life remain a mystery.

To address these questions and others, Dr  Andy Young from the University of Cambridge has set up a long-term field-study of Damaraland mole-rats here in Tswalu, in collaboration with Professor Nigel Bennett from the University of Pretoria.

MOLE-RAT PROJECT RESEARCH GOALS

• How do Damaraland mole-rats benefit from group living?
  If mole-rats do enjoy improved foraging efficiency in larger groups, they may grow faster and carry more body fat, which may also have knock-on effects on their fertility and survival.  Mole-rats in larger groups may also benefit from cooperative defence against predators such as mole-snakes. These predictions will be tested by comparing mole-rat growth rates, fat loads, fertility and survival etc. in groups of different sizes.
• Do workers really help rear the queen's offspring?
  Though Damaraland mole-rat societies resemble those of the ants and bees, with many non-breeding workers, it is unknown whether these workers do actually help to raise the queen's offspring or whether they simply share the colony burrow system.  This issue will be addressed by studying the way that offspring survival and growth rates are affected by the number of workers in the colony.
• How do workers prepare for the challenge of dispersing the found new colonies?
  Occasionally, workers from one colony strike out on their own and attempt to found a new colony.  If mole-rats do rely on group-living to succees in such a challenging environment, dispersal must be a risky process.  One goal of the project will be to explore the tactics that dispersers use to maximize their chances of success e.g. linking dispersal to rainy periods, amassing fat reserves, invading other colonies etc.

GOING UNDERGROUND
Damaraland mole-rats live in completely sealed underground burrow systems, creating some unique challenges for interested researchers!  The only tell-tale signs of their presence are the sandy mole-hills that they push up as they excavate their foraging tunnels after the rains.  Walking over such an area, there are likely to be 100s of busy mole-rats working away under your feet.

Andy and his team have set up a study site in southern Tswalu, comprising 22 colonies that range in size from 2 to 24 mole-rats.  To catch the mole-rats, they place drop-door traps in the colony's foraging tunnels, betrayed on the surface by clear lines of mole-hills.  Individual body measurements and weights can then be recorded (for working out growth rates and fat reserves) and urine and faecal samples can be collected to assess their hormone levels for stress and fertility studies.  Before being released back into their tunnel system, each animal is marked with a tiny ID chip so they can be recognized in future trapping sessions.

By tracking these colonies over the long-term, trapping each one twice a year, it will be possible to assess both the effects of group size on survival rates, and the number of workers on the queen's breeding success. Together, these findings will yield valuable insights into the forces that have shaped the lives of these amazing animals.

LOOK OUT FOR MOLE-RATS

There are mole-rats colonies in most areas of the reserve - look for the characteristic mounds of sand they push up after rainy periods.

If you would like a closer look at these enigmatic animals, please tell your field guide.  If the field work is being conducted at the time, they may be able to arrange for you to join an afternoon field session.

ANDY YOUNG
Andy comes from the UK and completed his first degree in Zoology at St. John's College, University of Cambridge. After working on a range of research projects, Andy returned to Cambridge to start a doctorate in zoology, focusing on the evolution of cooperative animal societies.  He spent three enlightening years studying meerkats in the Kalahari desert. Completing his work in 2003.  Andy is currently a research fellow at Magdalene College, Cambridge and has broadened his research focus with work on Damaraland mole-rats here at Tswalu.

His work at Tswalu is conducted in collaboration with Professor Nigel Bennett at the University of Pretoria and has been supported by funds from the Association for the Study of Animal Behaviour, UK.