Botswana's fencesKalahari

Over the past 20 years or more fenceshave been erected around the part of theKalahari that lies in Botswana withoutthought about the impact on the wildlife.Over the years the fences have taken amassive toll of animals whose traditionalmigration routes to water have beensealed off. The authors, who have beenworking in the Kalahari since 1981,examine the current situation and sug-gest some of the possible remedies thatare so urgently needed.We have been studying antelope movements inthe northern part of Botswana's Central KalahariGame Reserve since April 1981. In the course ofour work we have reached the conclusion that amassive decline of Kalahari wildlife populationshas occurred. One reason for this decline is obvi-ous. Fences now enclose much of that part of theKalahari that lies within Botswana, blocking orseverely disrupting wildlife movements both outof and into the region. In times of drought speciesthat are unable to cope with the abnormally aridconditions need to move out of the Kalahari toperennial water sources such as the Okavangosystem and the Limpopo and Orange rivers.Heavy mortality must result if their movement towater is blocked. In the periods of above averagerainfall, which regularly occur in southern Africa,improved conditions allow the movement of ani-mals into the Kalahari from the better wateredareas to the north and east. The ending of suchmovements must also reduce the overall abund-ance of animals in the Kalahari. At least onespecies has now completely disappeared from the218

A doomed wildebeest calf, left behind on the trek to Lake Xau(Douglas Williamson).

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and the depletion ofwildlife

Douglas Williamson and Jane Williamson

area. Zebra, which were reported by Silber-bauer (1965) as resident in the northern Kalahari,have not been seen there since the severedroughts of the 1960s. These were the first seri-ous droughts to occur after the erection of theveterinary cordon fences that blocked the migra-tion of zebra to perennial surface water.

Another species, wildebeest, still regularlymigrates out of the Kalahari during periods ofdrought, but now has only very restricted access

to surface water in the Lake Xau area. Theiraccess to the Limpopo and Orange rivers in thesouth-east and south is now completely cut off.The heavy mortality resulting from their disruptedmigration has been documented several timessince the erection of the veterinary cordon fencesduring the 1950s. Silberbauer (1965) reportedheavy mortality on the fences during the droughtsof the 1960s. Child (1972) described wildebeestdie-offs at Lake Xau in 1964 and 1970. Owensand Owens (1980, 1983a,b) have given detailed

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A veterinary cordon fence from the air. Like colonial boundaries, these fences are arbitrary lines drawn on a map (DouglasWilliamson).

Botswana's fences 219

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accounts of the migration of wildebeest and theirconcentration at Lake Xau.

A plausible explanation for the regular wildebeestconcentrations at Lake Xau was suggested to usby Dirk Kreulen, a Dutch scientist who worked inthe Kalahari as a member of a team employed tocarry out a range and animal inventory of theregion (DHV, 1980). He pointed out that thecontinuous barrier of fences from the northern tipof South Africa's Kalahari Gemsbok NationalPark to the end of the tail-end fence near LakeXau probably has the effect of funnelling all themigrating animals into the Lake Xau area.

The wildebeest always suffer heavy mortalitywhen they concentrate at Lake Xau but the situa-tion was especially grim in 1983. The area hadhad five years of below average rainfall and LakeXau itself was dry. Apart from a few pools, theBoteti River was also dry. The only substantialbody of water in the region was the Mopipi Reser-voir, which serves the Orapa diamond mine.Mopipi is east of Lake Xau, while the only shadein the area was to be found in the woodlands wellwest of the lake. Since high ambient temperaturesmake shade indispensable during the time of thewildebeest concentration the animals were ob-liged to make a round trip of up to 100 km eachtime they needed to drink. Moreover, the droughtand chronic overstocking of cattle had severelydepleted the grazing in the vicinity of Lake Xauand Mopipi. Large tracts of land had been com-pletely denuded of grass and there were regulardust storms. These extremely stressful conditionswere aggravated by the people living near MopipiReservoir, who, as well as killing a substantialnumber of animals, subjected them to variousforms of harassment, which almost certainlycaused heavy additional mortality.

The scene below the wall of the Mopipi Reservoirwas reminiscent of a First World War battlefield.In places the density of wildebeest carcasses ex-ceeded 50 per hectare. The nature of the inter-actions between people and animals at Mopipiwould make it difficult for even the most avidromantic to sustain the argument that aestheticsare a plausible motivation for conservation in thedeveloping world. Having witnessed these inter-actions at first hand, one is sorely tempted to220

agree with the collector in J. G. Farrell's novel,The Siege of Krishnapur, that aesthetics are 'asham... a cosmetic painted on life by rich peopleto conceal its ugliness'.

In addition to contributing to the disappearanceof zebra and to the plight of migrating wildebeest,there can be little doubt that the fences, in con-junction with expanding human settlement, alsoprevent animals normally resident in the betterwatered areas to the north and east from movinginto the Kalahari during periods of above average

ZIMBABWE

N 0 50 100 miles

J 0 50 100 150 200 km

Fences around the Kalahari.

Fence.National Park/Game Reserve Boundary.

Fencesvcf—veterinary cordon fence.1. Namibia/Botswana boundary.2. Ghanzi ranches.3. Kukevcf.4. Makalamabedi vcf.5. Tail-end vcf.6. Central Ngwato vcf.7. Main road/railway line.8. Dibetevcf.9. South Africa/Botswana boundary.

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One of the many carcasses in the area west of Lake Zau.Drifting sands are beginning to cover it (Douglas Williamson).

Some wildebeest reach the water, many die around it(Douglas Williamson).

rainfall. We have evidence both from the litera-ture (Silberbauer, 1965; Campbell and Child,1971) and from interviews with Bushmen longresident in the area that species such as elephant,rhino, buffalo, roan, sable and tsessebe regu-larly moved into the northern Kalahari duringperiods of above average rainfall. All thesespecies are now absent from the Kalahari.

In addition to the fences we are aware of no fewerthan eight factors that must also be contributingto the decline of Kalahari wildlife. One of these,the spread of pastoralism, has been operating fora very long time but its rate of spread has accele-rated drastically since the 1950s, when the sink-ing of boreholes in otherwise waterless areasbegan on a large scale.

The other factors are:the prevailing drought;expanding human settlement;the erection of yet more fences;the proliferation in hitherto inaccessible areas ofnew roads and tracks made by mineral prospec-ting companies;the diversion of the Boteti River to supply waterfor the Orapa diamond mine;the settlement of large numbers of people in thevicinity of mines in previously remote areas;illegal hunting on a very large scale.Botswana's fences

Our contention that Kalahari wildlife populationshave been drastically reduced is not based onlyon the disappearance of a number of species andthe identification of various factors which must beadversely affecting wildlife. The results of anaerial survey programme that we have been con-ducting provide a modicum of quantitative evi-dence in support of this contention.

In each of the first two years of our study wecompleted six extensive aerial surveys andpooled the results of these to make an estimate ofmean large herbivore biomass through the year.We have compared these estimates with ex-pected biomass, which we calculated using atechnique developed by Coe et al. (1976) andbased on the dependence of large herbivore bio-mass on rainfall.

In the first year of our study the observed largeherbivore biomass was only 24 per cent of theexpected value. In the second year this declinedto about 11 per cent of the expected value. Thisdrop was almost entirely due to a steep decline inthe number of wildebeest entering our study area.Other populations remained remarkablyconstant. Because our aerial survey work isunavoidably fraught with inaccuracies arisingfrom our limited manpower and equipment, itwould be disingenuous to imply that our esti-

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mates of large herbivore biomass should beaccepted uncritically. The overwhelmingprobability is that we have underestimatedpresent biomass, but the discrepancy betweenthe observed and expected values is so enormousthat we nevertheless have no doubt that there hasbeen a massive reduction of large herbivore bio-mass in the Kalahari. Our confidence in this con-clusion is considerably stengthened by the factthat the biomass estimate for the first year of ourstudy is virtually identical with a biomass estimatefor the whole Kalahari made in 1979 (DHV,1980).

On the basis of the evidence that we havecollected, we infer that wildlife faces a bleak futurein the Kalahari and in view of this inference wehave felt obliged both to try to understand howthe existing situation has arisen and to considerwhether or not anything can be done to ameli-orate it. As we understand it, the existing situationis partly the unintentional result of a number ofuncoordinated fencing schemes and partly a re-flection of a widespread indifference or even hos-tility to wildlife conservation.

The fences around the Kalahari include the inter-national boundary fences between Botswana andNamibia and Botswana and South Africa, fencesalong main roads, ranch fences and veterinarycordon fences. They have been erected over aperiod of more than two decades and there is noevidence of any consideration having been givento their impact on wildlife populations.

Indifference to wildlife conservation has a certainlogic when one views the world through the eyesof rural people living at a meagre subsistencelevel. To such people wildlife is seldom more thana source of free meat and hides and, perhaps, ofadditional income and it is often a nuisance or athreat. It is also logical for people who seeeconomic development as an overriding concernto accord a low priority to wildlife conservation.Present economic benefits from wildlife are verysmall compared to those derived, for example,from the cattle and mining industries in Bots-wana.

Although we can think of no programme thatcould be guaranteed to reverse present trends inthe Kalahari, we believe that there are steps thatcould be taken that might result in an improve-222

ment in the situation. These include:a detailed assessment of the ecological status ofthe Kalahari ecosystem;formulation of an integrated land-use plan for theKalahari in terms of which orderly developmentof the region could occur;formulation of a management plan for the CentralKalahari Game Reserve;a pilot project for the provision of artificial watersupplies for wildlife in the Central Kalahari GameReserve;a radical upgrading of the law enforcement capa-bility of the conservation authorities;vigorous promotion of the development of wild-life-based industries, with the object of convincinglocal people that the wildlife resource is a valuableasset with the potential of contributing signific-antly to economic development.

We make no claim that these suggestions areeither comprehensive or definitive. We simplywish to illustrate that remedial action is possible.Clearly, it is also increasingly urgent.

Acknowledgment

Our research is sponsored by the Frankfurt ZoologicalSociety.

References

Campbell, AC. and Child, G. 1971. The impact of man on hisenvironment in Botswana. Botswana Notes and Records,3,91-110.

Child, G. 1972. A wildebeest die-off at Lake Xau. Amoldia,5(31), 1-13.

Coe, M.J., Cumming, D.H. and Phillipson, J. 1976. Biomassand production of large African herbivores in relation torainfall and primary production. Oecohgia, 22,341-354.

DHV Engineering 1980. Countryside Range and AnimalAssessment. Report to Government of Botswana, 5 vols.

Owens, M. and Owens, D. 1980. The fences of death. Afr.wild Life, 34(6), 25-27.

Owens, M. and Owens, D. 1983a. Fences of death. Wildlife,June, 214-217.

Owens, M. and Owens, D. 1983b. Kalahari migration. Int.Wildlife, September-October, 32-35.

Silberbauer, G.B. 1965. Bushmen Survey Report. BotswanaGovernment Publication, Gaborone. 138 pp.

Douglas and Jane Williamson, POBox40, Maun, Botswana.OryxVoll8No4

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