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2 Notes on Some Effects of Extreme Drought in Waterberg

Even before the advent of man, the gradual but continuous diminution of the surface water of the earth was undoubtedly the chief element in our cosmic history. The change in environment this occasioned has been the great moving cause of natural selection and the evolution of living species.

If we study this loss in the two continents where the scarcity of water has reached such a degree as to render its present lessening an outstanding natural feature, the rate not only becomes more noticeable, but also more easily measurable. In Asia and Africa, the two ‘dry’ continents, the disappearance of water annually is so great it seems to justify the prediction of the French astronomer, Flammarion, that within a measurable space of time the human race will find its final eclipse in this cause. In Europe and America, the ‘wet’ continents, water is still too plentiful to make its yearly lessening a matter of much moment; but they are certainly not exempt. If one compares, for instance, the facts disclosed in the histories of early Roman conquest with existing conditions, it would appear that what are now comparatively dry countries and fertile tracts were in those times an unending succession of marshes with broad, sluggish rivers winding from mere to mere.

In Asia, a comparison between the observations of the Russian explorers of fifty years ago with those of Sven Hedin reveals that even in this short time the desert has taken over thousands upon thousands of square miles of once fertile country. Rivers and lakes have vanished and even populous cities have been obliterated by the all-conquering sand.

The great lakes of Africa are shrinking just as rapidly. Our own N'gami was a real lake less than fifty years ago; now it is no more than a marsh threatened with speedy extinction. Lake Rudolf, that most perfect diadem in the girdle of the globe, is approached on one side (that opposite Ruwenzori) across an enormous plateau of dry mud which quite recently was covered by the waters of the lake. Yearly, a new belt is added to these mud flats - a progress that becomes alarming when one remembers that upon this great natural reservoir largely depends the fate of the Nile and of fertile Egypt.

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Nothing is more fallacious than the old doctrine that evaporation and precipitation of moisture constitute a perfect cycle without the possibility of loss. As a matter of fact, the earth is sucking up moisture like a sponge, and each day a vast quantity penetrates the surface to subterranean depths from which no natural cause releases it again and where it is apparently beyond the reach of man's utmost ingenuity.

The recent geological history of Waterberg is, in this respect, extremely interesting and convincing. That, by ‘geological time’, the major portion of its surface was recently covered by a great lake is beyond question. The water's barrier to the north was a plateau of which a portion still remains in situ. A few of the original islands, now strangely formed lambdoidal hills with the wave marks still visible on their rocks, stand like a row of sentinels in the low country just beyond the edge of the plateau. From the south great rivers deposited their shingle on the shores and bottom of the lake. Some upheaval destroyed all the eastern portion of the barrier, and the confined waters escaped northwards and eastwards to form new rivers when the first floods had subsided. The shingle mixed with the lake sand was buried under the products of this eruption, and after being subjected to immense pressure, the lapidescent stuff was released by another cataclysm and scattered over the entire district, where it is now known as Waterberg Conglomerate. The highest hills and the lowest valleys are studded with highly polished lacustrine pebbles, looking as if yesterday they had been taken from the water. Only on the uninjured fragments of the plateau which once formed the heights above the lake shore you find none, but just below the surface on the slopes of this high country there are layers of beautiful lacustrine shells sometimes two or three feet in depth.⋆ Since that débâcle, the geological history of Waterberg has chiefly been one of rapid desiccations. Broad over its surface lies the writing which he who runs may read. There was a time, within the memory of white men, when every kloof and donga was the bed of a perennial stream of crystal water and the district generally was so marshy and vals as often to render a passage by ox-wagon hazardous. Its present name was bestowed on the district in those times - a name that today seems to have originated from the bitter irony of some disappointed Voortrekker.

Even within the last half-century Waterberg was, to dwellers on the highveld, synonymous with a lotus land of fertility, literally overflowing with milk and honey. So plentiful were these two emblems of fruitfulness that the good wives used to fatten their pigs on a mixture of honey and ‘thick’ milk. Fruit, wild and domestic, was proverbial for size and plenty. Every farmhouse had a water-mill, and a spirit, still smoking night and day. It was the last great stronghold of big game in the northern Transvaal. Makapan invited Commandant Potgieter to Schimmelperd-se-pan for elephant shooting when he planned

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the murder. Perhaps it is true, too, that here man had to procure his bread by the sweat of his brow. He had to work in order to live, but his work was so uncommonly like play that, not without reason, the district was named ‘Luilekkerland’. A strong horse and a good rifle were the prime necessities of life, and many a fine farm was swapped for one of these.

That was the picture then. And now? Tantaene animis celestibus irae?

Last season was a culmination of several drought years. It was the worst drought experienced in this district since the advent of the Voortrekkers, and this statement is made on surer evidence than the unassisted recollection of the ‘oldest’ inhabitant. One cannot be too doubtful of such ‘facts’. An eclectic acceptance of this sort of statement can provide foundation for almost any theory. Even one's own recollection must be consulted with considerable reserve. No one who has grown up in this country but seems to remember a Transvaal of broad deep rivers, of mighty rains, of beautiful springs, spruits, and waterfalls. Valuing this no more than one would hearsay evidence in law, there is in Waterberg a mass of confirmatory proof which places the statement beyond doubt. Take only one fact: last season a large number of orange groves with trees over fifty years old perished from drought. And in addition to such facts, a little study of drought conditions and the diminution of existing water soon enables one to follow the ancient tracks of once living streams, and even to assign an approximate date to their final disappearance. With such collateral evidence human memory can, tant mieux, be valued correctly. The assertion, therefore, may be safely accepted.

Over the greater portion of the district the first rains did not fall before the middle of November, and over about half of the northern middle veld no rain fell at all, that is to say, not sufficient rain to cause the veld seeds to germinate and the plants to grow. This season has, in certain respects, been even more disastrous. In the early part, there were good, but purely local, showers. The grass and shrubs in these favoured localities started fairly well, and then, when rain was most needed for crops and veld alike it ceased altogether. This refers to the plateaux and mountains. In the north, with the exception of one or two localities, no rain has fallen this year, and again it is the end of November.

The effects of such a drought open a vast field for research, of which almost every ascertained fact would be of the most vital importance to the inhabitants of South Africa. Not to the naturalist only are these facts of interest and value. To the farmer their study would afford an essential arm in his struggle for existence. But in an article such as this it is possible to touch on a few of these facts only. Many experiments and comparative measurements were made which might be of some value for the purposes of exact research, but a detail of them would hardly be admissible here. I will confine myself, therefore, to a brief description of the more immediately perceptible effects of the drought on sur-

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face water, on plants, and on animals - facts that would strike any observant visitor.

It is impossible, unless one saw, to conceive the scene of utter desolation in that once famous hunting ground between Gaul and Magalakwen, extending northwards from the mountains to the Limpopo and constituting the lateral watersheds between the three river systems. The two rivers, Magalakwen (‘the strength - or stronghold - of the crocodile’) and Palala (‘the barrier’, ‘the stoppage’, ‘the impossible’), bearing in their Native names proof of their former greatness, are today mere ribbands of sand winding through desolate sand dunes to the Limpopo. For some distance along their courses one can still find water by digging holes in the sand. It will try the reader's faith to learn that in the entire district of Waterberg there is at the date of writing, with perhaps one exception, no running river or spruit, and Waterberg is, I believe, considerably larger than the Free State. In the north of the district there is a tract over four thousand square miles in extent in which there is no single drop of water - running or stagnant - above the surface of the ground.

Schimmelperd-se-pan, the last great centre of elephant hunting in the Transvaal, received its name from the legendary feat of an intrepid Voortrekker. Braving its dangerous subaqueous weeds, he made his horse swim across the pan with a quarter of an eland tied behind the saddle. Now there is never more water in the pan than can be covered with a lady's pocket-handkerchief. The water supply consists of a tiny pool deep under a sheltering rock and, as I write, this has shrunk away till nothing is left but a patch of damp sand. For the first time within the memory of man, all the famous old waters of the great hunting days have similarly disappeared, although to those who had the opportunity of studying their annual shrinkage their fate has been a foregone conclusion for many years. Tambootie, a huge marsh, always dangerous to cross; Sandmansfontein, a beautiful strong spring in the hills, named after the only hunter who attempted to make his home there in the old days; Bobbejaanskrans, where the water boiled out under a precipice and where the finest Kaffir cattle in the middle veld were to be seen three years ago - all have vanished, and with the ending of the waters the great herds of cattle have fled in all directions. All that once-teeming pasturage lies dead and desolate.

But it is not in the middle veld alone that this state of affairs obtains. There are hundreds of farms in our immediate vicinity which have the same tale to tell. One can take them completely at random. Zwartkloof, for instance, was selected by the late Mr Piet du Toit, a Voortrekker, on account of its magnificent water supply. Until recently it was still renowned as one of the best wheat farms in our ward, and its great herds of wild red Afrikaner cattle were hunted and shot like big game up to the time of the rinderpest. The present joint owners, Messrs Franz and Nols du Toit, were born on the farm. The

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former is now sixty-five years of age. He declares that throughout his lifetime there was never even a perceptible lessening of the spruit, yet today a well, forty feet deep sunk in the source itself, is as dry as a bone. There is not a drop of drinking water on the farm. Thirty years ago there were no less than eleven perennial springs in its veld. And this same story can be told of almost every occupied farm in Waterberg.

The great Limpopo itself is dry for all the distance that its course delimits this district. Only by deep digging in its sandy bed can drinking water be found. The larger hippopotamus pools, it is true, still contain stagnant water, but the majority of these are almost putrid. The smell of fish and crocodile poisons the air in their vicinity, and it would be courting death to drink the soupy liquid they contain without previous filtering and boiling. After the recent heavy rains in Pretoria and Rustenburg, and the floods consequent on them, the running water in the Limpopo reached thirty miles above Silika's stat and then - a mere futile trickle - was lost in the burning sand of the river bed. Of all the immense quantities of water which drained off the northern slopes of the highveld then, and at one time most of the tributaries of the Limpopo were flooded, not one drop reached the sea as flowing water.

The only waters in the district which remain unaffected by the drought are the fairly numerous thermal springs. The farm on which I reside is dependent for all its water - drinking and irrigation - on a thermal spring, and careful measurements during the past five years show no diminution at its source. But this year the loss of water between the source and the dam inlet is sixty per cent higher than it was on the same day three years ago.

The effect of the drought on plants is naturally in exact proportion to its effect on surface water. Early in the season of 1913 the belief gathered strength that a large proportion of sweet-grass clumps in the affected veld were quite dead. Under magnification the deepest roots showed a state of desiccation precluding the possibility of life. This, however, was strenuously contended by the experience of old settlers. They seemed to think that, as long as they remained in the ground, no amount of drying-out could kill grass clumps. To decide the question, it was attempted to start growth by damping and shading two hundred clumps of sweet grass of different varieties growing on zoetdoornveld. The result showed ninety-two per cent were quite dead. The average number of seeds that germinated in and near these clumps was three. Before the end of the season, however, most of the seeds produced by this artificially induced growth were destroyed. Just enough rain fell to start germination, and when they were at the tenderest stage the sun scorched them to death. An enormous extent of sweet veld has been destroyed; this farm looks more like a barren brak than the luxuriant pasturage it once was.

The coarser ‘sour’ grasses (Aristidas) to a greater extent escaped complete

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destruction. Their manner of growth enables the clumps to resist drought better. The thick fibrous covering just above the ground affords more root shade and is also a more absorbent medium than the scantier clumps of the finer grasses. It seems to me quite evident that these so-called ‘sour’ grasses are comparatively recent invaders from the desert to the north, where natural selection has long since fitted them to resist similar conditions. The native sweet grasses, not able to adapt themselves to this changed environment, are losers in the struggle for existence. This is why all our sweet veld is yearly diminishing and the sour veld extending. In fact, it is almost impossible to get quite pure sweet veld in Waterberg. Our best land would have been called ‘mixed veld’ a few years ago. In the olden days Waterberg was a sweet-veld district.

It is in their seeds that one can best see the high specialization attained by the sour grasses as drought resisters. Their manner of distribution and habit of growth were all evolved under stress of waterlessness in some semi-desert country. Their life-history is one of those fairytales of botany that might be of interest even to the busy man who has no time to notice. With a body like a torpedo and a long, tapering tail, they have attained in perfection the tadpole shape, which nature finds of such advantage that she has evolved it a thousandfold in the highest and lowest forms of life - indeed, it is probable that all organic forms originated from such a shape. Under low magnification, it can be seen that both body and tail are thickly studded with sharp, stiff bristles growing backwards. The point of the torpedo is an intensely hard, horny spike, sharp as a needle, with a coronal of harpoon points at its base. The seed is thus able to cling to the coats of animals, besides being easily carried off by the wind. But these qualities are of more immediate value in another direction. It is above all things a penetrating machine - how efficient one can judge from the fact that it is often found in the internal tissues of animals, having gone through coat, muscle, and flesh. It often penetrates human flesh, and is then a serious source of danger. Every movement, however slight, causes the imbedded seed to penetrate deeper, and frequently only surgery can remove it. But it was not for just this purpose that its penetrative qualities were evolved. It is a common thing, in good rain years, to come across a mass of these seeds drifted together by the wind. It is then that one has an opportunity of seeing a wonder of plant life, quite startling in the apparent intelligence disclosed. The seeds, as they lie, are huddled and orderless like casually thrown spillikins. If one sprinkles a little water on the mass a tremor as of awakening life is almost immediately seen to pass through them. Movements in all directions follow: spasmodic jerks, twistings, and turnings, so animal-like as almost to leave one in doubt whether they veritably are seeds and not insects. And this doubt intensifies as the process continues and the purpose becomes more apparent. One

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sees that by these movements the seeds are disentangling themselves; and when this is affected, each one becomes engaged in independent movements. At first it all seems erratic and casual, and it is only after careful watching that it dawns upon one that all these movements are quite ordered and have a definite purpose. The first spring-like twistings lift the seedhead clear off the ground and free it from obstructing fellows. A bend of the tail, on which it then rests, turns the torpedo head earthwards. It is gradually lowered until the needle point with its harpoon bristles is thrust into the damp soil by a steady and continuous pressure from the tail. This movement is continued until the entire seed is imbedded, the whole operation occupying fifteen minutes. But its chief protection against drought and the accompanying ineffective and, in fact, fatal night showers lies herein, that if the soil be only slightly damped the seed penetrates beyond the line of moisture and remains thus without germinating, ready planted, waiting for enough rain to ensure the safety of the future seedling. This penetration is proportionate to the length of the tail, and it will be found at the end of a season of severe drought that the species with the longesttailed seeds have started more seedlings than the relatively short-tailed. The hard shells of these seeds also require a definite and large amount of moisture to soften.

The seeds of the sweeter and softer grasses are deprived of all these advantages. The clumps die and the seeds germinate with the first slight shower, only to die next day in the scorching sun. And thus it happens that yearly the famous sweet veld of Waterberg is diminishing and getting more and more mixed and its value as a cattle district is proportionately deteriorating. And not only are the sweet grasses thus handicapped by changed environment, but man enters into the fight against the losing species and by the annual veldfiring assists, and even completes, the work of natural selection.

And not only the pygmies of the veld have been struck down. The giants, secure in their strength and age, have not escaped. The big trees are leafless and sapless like a northern woodland in the midst of winter. On the higher hills fifty per cent are quite dead, food for the next veld-fire. Many of these dead trees are at least three centuries old - calculated from the annulation in timber sawn from them.

Even the most efficient water-storers could not survive this terrific length of drought and heat. In the middle veld the little naevose aloe, common on our southern hills, grows plentifully on the flat, chiefly in the shade of thick bushes. When this shade was deficient they commenced dropping their leaves from the crowns downwards and, before the middle of the season, they were quite dead. Stapelias, those weird daughters of the desert, are very plentiful here. Under normal conditions they seem to shun every semblance of moisture by growing on barren shelves of rock, collecting a scanty soil by means of their

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own roots; but now even stapelias hang shrunken and flaccid on their rocks, and quite half the plants examined seemed quite dead.

It was a surprise to find the large hypoxis one of the best drought resisters. Not only did they start a fair growth of fronds, but in shady places even a few sickly flowers appeared. This plant has a medium-sized bulb, not nearly as large, compared with its growth above ground, as hundreds of others that perished. The bulb is enveloped in several layers of dry, perfectly water-proof husks, and is filled with a sticky, orange-coloured liquid. What made it of special interest was that it was eagerly sought and eaten by all kinds of animals in preference to any other plant procurable. Even the well-fed animals in our team were eager for it.

The effects on the animal world were just as far-reaching and quite as noticeable. Those animals to whom escape was possible fled early from the stricken area - man among the first. The entire middle veld is without human inhabitants. Whites and Blacks trekked north and south along the riverways with their stock as the waters receded, and a great many cattle have been sent on to the high country. For all practical purposes the north is a desert, and in many respects a worse desert than the Kalahari. In the middle of the day it is a scene of utter desolation. Not a bird sings, not an insect moves. The silence of absolute lifelessness seems to lie over everything - a silence characterized by the true desert tinnitus. Elsewhere it is said that the wind loweth where it listeth. Here - when a breath of air does come - it has a strong predilection for one direction only: straight from the Kalahari, hot and scorching as the breath of an oven. It seems indeed as if the desert has reached out an arm and taken to itself for all time this great extent of once fertile country. For four-and-a-half long hours each day in the coolest available spot the temperature never sank below the century.

This terrible heat and the absence of all moisture in the atmosphere had some singular effects on the human body and its immediate environment. The hair became so electrified that to stroke it lightly with the hand evoked a crackling shower of sparks. The fingernails became so brittle that they were constantly breaking into the quick, and both the hair and nails seemed to have lost all power of growth. All celluloid substances were speedily broken up into thin laminae and, in a few days, new rubber became a useless spongy mass. The horses' tails, swishing their sides, crackled incessantly and stood out in dishevelled bushes, each hair apparently wired. When travelling at night their flanks were surrounded by miniature auroras of electric discharges. To stroke the canvas with one's finger generated a discharge that could be felt in the hand.

The big game had nearly all disappeared. The large herds of blue wildebeeste that had frequented the rivers earlier in the year trekked down the Limpopo to the larger pools and across into Rhodesia. The change of habit forced

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upon animals by this change in their environment was very interesting, and in many instances remarkable. The first thing we noticed was that ant-bears, famished and unafraid, were walking about in broad daylight. These unfortunate edentates, among the most highly specialized of mammals as far as its food supply is concerned, seemed to be in desperate straits. I had an opportunity of observing for the first time a baby ant-bear out hunting with its mother at midday. The reason that compelled these most nocturnal and shyest of animals to abandon so fixed a habit was immediately apparent. The termites, on which they feed exclusively, live only in hard soil. In the sand dunes there are none. This termite-infested soil was as hard as a rock, and though the ant-bear is the most perfect of mining machines, the hours of darkness were not sufficient for them to reach the nests. Hence were they driven to work in daylight too. Everywhere in the areas of red soil we found abandoned attempts at shaft-sinking. On another occasion, we found the ant-bear's cousin edentate, the armadillo, out in the morning. It was a female and carried a baby of a few weeks old on its back, the tails firmly interlocked.

For the same compelling reason - hunger - most nocturnal beasts of prey hunted during the day as well as by night. Two leopards raided a small Black stat in the vicinity of our camp and carried off a pig during the early afternoon. The unfortunate baboons apparently never slept at all. Weird and ungainly skeletons, they were fearless through starvation. In normal times no animal is more frightened of the dark than the baboon. Nothing will induce them to leave their sleeping-place before the dawn is well advanced, and they are always careful to be safe on the cliff before the approach of night. And now all night long we heard their human-like lamentations as they searched the river banks for food, devouring everything and anything that was remotely entitled to the name.

Where the crocodiles had disappeared to was at first an insoluble enigma. The few stagnant pools in the Limpopo, of course, swarmed with them, but this could not possibly account for the numbers that rendered every pool in the Magalakwen, Palala, Gaul, and the Crocodile rivers dangerous in rainy seasons. A possible solution was afforded while we were digging for water in the sand half-way down the Magalakwen. In the centre, the hole had to be at least six feet deep in order to reach the water level, and that meant it had to be at least twenty-five yards in circumference. Four-and-a-half feet below the surface we came upon a little three-foot long crocodile, apparently dead. It was just below the level of the damp sand. Although seemingly lifeless the body was quite limp and fresh. We also found a number of small fish known to the bushveld farmers as makriel. They are the northern representative of the well-known barbel. These, too, seemed quite lifeless. I placed the fish in a bucket in direct sunlight and aerated the water at intervals by pouring a stream from a kettle

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held at a considerable height. In ten minutes they began to show signs of life, and in a quarter of an hour they were swimming about in the bucket apparently none the worse for their long sleep. We revived the crocodile within half an hour by placing it in a hole scooped in the sand under the shade of a tree and occasionaly pouring a bucket of water over it. The moment it woke to life some strange instinct seemed to compel it to burrow down into the sand again.

Judging from the tracks and from actual observation, it seemed that most of the animals still subsisting in this deadly waste had learnt to dig for water in the river-bed. The most efficient diggers were the baboons and the warthogs, and my companion - an old hunter and clever veldman - pointed out an interesting fact: all day long every sounder of pigs was followed by a regular retinue of other animals, apparently for the purpose of using their water-holes after thirst had driven the warthogs to the river-bed to dig.

One quite unexplainable thing observed in certain parts of the Springbok Flats during the height of the drought was that the ordinary white ants (wingless) came out of their holes in vast numbers, and lay in the sun in a closely packed ball all day long. The ground next to such a ball was so hot one's bare hand could not stand contact with it for more than two or three seconds. I was anxious to ascertain the temperature next to them in the direct sun and placed a thermometer close against a ball of ants. Unfortunately the scale only went to 60 centigrade (140 Fahrenheit) and the mercury rose to the top of the tube in a few minutes. This terrific sun-bath did not seem to injure the ants' aetiolated bodies at all. In the cool of the evening they trekked back to their underground nests.

The only animals which suffered no perceptible inconvenience, although they were also driven to a change of habits, were C. pictus - the terrible hunting dogs. In the middle veld during ordinary times they only drive during the day - mostly in the early morning. But now, on account of the terrible heat, they hunted at night, and we were often rudely awakened by their noise. On one occasion a troop drove a full-grown rietbuck ewe right through our camp while we were sitting in the light of a big fire and pulled her down in the river-bed within twenty paces of our carts. On another one of our donkey stallions was driven two miles before they captured and devoured the unfortunate animal. Judging from their threatening and fearless daylight attitudes I have not the least doubt they would attack a human being if the least indication of fear and retreat became apparent. We once had the pleasure of assisting the poisoning of a troop that had killed a full-grown male ostrich near a neighbouring camp - within a few hundred yards of the tents. This appeared to be a new prey. Several old Waterberg hunters assured me they had never before heard of wild dogs driving an ostrich, and several of them doubted the possibility of capturing a full-grown healthy male.

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The vociferous white-headed sea-eagle, which every visitor to the East African coast will remember, if only on account of its clear triumphant shout high up in the clouds above some estuary, has always been a rare visitor to Waterberg during the early summer. The late Dr Gunning thought they were driven inland by storms on the coast. This is a mistake. There can be no doubt the real reason for their travels so far inland is the drying of the streams, which afford them a plentiful and easily attained food supply. They follow the course of a drying stream as long as there is any chance of securing fish. We found a large number of these birds on the Magalakwen, more than I have ever seen together anywhere. They were apparently caught - as in a trap - by the drying of the streams behind them. No longer were they noble denizens of the clouds, clean feeders, swooping from the blue to plunge into the fresh clear water as in their native haunts. Here in the middle veld they had become simply vultures, quarrelling over fragments of carrion left by the wild dogs, and picking up putrid crabs and fish along the river-banks.

But if I attempt to describe even in outline what the drought has done to the birds of Waterberg, I should need an entire issue of the Journal. However interesting the subject, it cannot be gone into on this occasion.

In the presence of this scene of death and desolation it is difficult to cultivate a spirit of optimism. It does not seem possible enough water can ever again fall to damp or even to cool this parched and cracked earth and to fill these moats of burning sand. Optimism suggests it is only the great tidal swing of nature exemplified; that we are at the lowest point of the periphery, and that from now onwards it must rise steadily to better things. But at the back of one's mind remains the pessimistic conviction, apparently borne out by every fact observed, that the oscillations of the pendulum are gradually lessening round the deadpoint.