C.F. HEMMING (*)(*) C.F. Hemming: Centre for Overseas Pest Research London.
In the overstocked grazing lands of the more arid parts of Africa, the role of the rangeland surveyor is to make ecologically sound recommendations which are also politically acceptable. The closest cooperation with the government is essential. The recommendations that result from the survey must also be financially possible. The examples of range improvement by the making of charcoal from unpalatable woody species by licensed burners, and the making of fodder in closed grasslands, possibly by cooperatives, are cited. Both these examples would also create jobs, and illustrate how the proportion of the population dependent on the range as graziers could be reduced by politically acceptable and economically feasible methods.
In the better-watered rangelands of Africa, with a mean annual rainfall above 400-500 mm, the problem is often how to manage the grazing in such a way that it can support the maximum amount of stock compatible with the maintenance of the basic natural resource, that is, the vegetation. It is essential that the productivity of the rangelands be preserved in order that they may support future generations of man and his stock. In these areas the aim of a rangeland survey may be to classify the land into different ecological zones, each requiring different systems of grazing management.
In the drier areas in which I have worked, such as the Somali Democratic Republic, eastern Ethiopia and north-eastern Kenya, the situation is often quite different, the basic problem being how best to manage the land, which is at present carrying more stock than it is able to support, without causing undesirable changes in the vegetation.
The changes that can be caused by over-grazing are so numerous that I shall not attempt to describe them here except insofar as they illustrate particular points.
In other sessions of this seminar, you have heard of some of the successes that have ensued from the evaluation and mapping of rangelands. I think we would do well to consider some of the failures, in order that we may learn from them and not make the same mistakes again.
In the drier rangelands the people and their stock are normally nomadic, or at least they move regularly on a seasonal basis. In many countries such areas represent a large proportion of the country, and the people, owing to their nomadic ways, are less directly under the control of the government; thus the amelioration of the nomads' life and the management of the national grazing resource represent very difficult and dispersed tasks.
Initially ecological surveys are usually requested by a government because it realises that the areas in question constitute a potentially important element in the economy of the country. This is indeed true, and we as scientists, rangeland surveyors, or managers must realise that we can do nothing without the whole-hearted support of the government concerned. It is therefore essential that we encourage the government to feel deeply involved at all stages, and ensure that our suggestions are not only ecologically sound but also politically acceptable.
What should be the object of the initial survey of a new area? This really is a vital question. I personally feel that it should be to assess the present situation in the area with a view to making recommendations for its development for the benefit of all its people, not necessarily just the graziers On the initial survey one must examine the vegetation and determine in which ways it is changing and the reasons for these changes. For example, are some areas getting worse because overgrazing is causing a change from perennial grasses to annual ones? Are grasslands being invaded by woody shrubs, or is there even a wholesale change from palatable to unpalatable species?
When a series of such changes are found in an overstocked area it would be easy to recommend firstly destocking, secondly the improvement of the rangeland by the systematic removal of undesirable species to give desirable species a better chance, and thirdly the introduction of a system of controlled grazing. All these recommendations might be reasonable on ecological grounds, but the proposal to destock would often be politically quite unacceptable, and the other suggestions beyond the resources locally available.
The same government that cannot agree to a policy of destocking might nevertheless realise that it is desirable if it can be achieved in an acceptable and gradual manner.
In areas which are not overstocked, the ecologist has a reasonable chance of getting his recommendation turned into effective action, but in overstocked areas the ecologist's chances depend upon his appreciation of local political and economic conditions, as well as the basic ecological factors at work.
The real question, therefore, is: What can actually be achieved under conditions of heavy overstocking?
I know that what I am about to say is a rangeland heresy, but I consider that in some areas the concern of the ecologist or surveyor must be to make recommendations simply to ensure that the overstocked rangeland deteriorates at the slowest possible rate. I do not regard this as a counsel of despair, as some of you will probably do, but rather as a matter of facing the facts.
If we make recommendations which, when they are carried out, give us a breathing space of a few years with a reduced rate of destruction of the rangeland, we must ensure that we also have suggestions as to how the stocking rate can be reduced by politically acceptable methods which are also in harmony with local ecological conditions. The main object of a gradual destocking policy is clearly to reduce the number of animals on the range, and this usually also means reducing the proportion of the population dependent upon grazing for their livelihood.
The life of the nomad is an extremely hard one, and there is little to suggest that he is unwilling to give up this hard way of life if an alternative is available. I think, therefore, that the key to this problem may lie in the answer to the question: What can be done in this predominantly grazing area which will provide alternative jobs and which will, in the long run, enable the improvement of the rangelands and subsequently their maintenance at a high productive level?
Before going on to suggest some of the ways in which the rangeland might be used to provide jobs and get graziers gradually off the range, I would like to say a word about the need for the long-term view, illustrating this point with a simple example.
Some parts of the present Somali Democratic Republic were the subject of grazing surveys some 30 years ago. While these surveys concluded that overgrazing had already produced many adverse ecological changes, they also noted that some areas were in a much better condition than others.
One of the characteristics of the better areas was that water was available for only part of the year, and thus for many months each year all the graziers were forced to leave. These areas were therefore under a simple natural system of grazing control, even though it was possible to detect a change from perennial to annual grasses in the open woodland. It was decided that wells should be dug in these areas in order that their grazing period could be extended and so take the pressure off the overgrazed areas. The provision of bore holes and free water all the year round has, however, proved a mixed blessing. For the graziers living in these areas today life has certainly been made easier, but for those who will live there in future generations life will be harder owing to the severe overgrazing that has occurred near the bore holes by stock which has settled in these areas. This overgrazing has now been exacerbated by the construction of thousands of concrete-lined tanks to collect and store rain water run-off, which has caused the overgrazed areas to be extended away from the bore holes.
In another area in which I have worked, the soils consist basically of a very fine sand. Overgrazing around bore holes has removed the vegetation that formerly bound the soil, and large sand dunes are now to be found at the edges of villages. In the same area a snatch-crop can be grown in a wet year, and large areas have been cleared in order that the would-be cultivator can plant immediately after a good fall of rain. The good rains have, however, seldom been forthcoming, and the fields have become centres of wind erosion and are now almost useless to cultivator and grazier alike.
All these wells were dug with the best of intentions, but except on a short-term basis it now seems likely that it would have been better had a different policy been followed.
I think that this example illustrates more than anything else the need to take a long-term view. It is, of course, often difficult to know exactly what the long-term results of what we do today will be. This knowledge is, however, badly needed if surveyors are to have a reasonable chance of making the right recommendations, and it can only be obtained from research under conditions which are truly applicable to those in which the surveyor is working.
I would like now to turn to some of the considerations which may be useful when discussing the development of overgrazed semi-arid rangelands.
It might be well to consider briefly the object of having animals on the range. The animals provide a livelihood for those who keep them and a source of food for the country, and in some areas the animals represent a valuable export either as meat or as hides. In an overstocked area it is particularly important that marketing arrangements should be good, so that the herd owner can cull his herd and thus have no excuse for keeping non-productive animals on the range. The development of marketing arrangements does not normally fall within the duties of the rangeland ecologist or surveyor, but he may at times feel compelled to draw attention to the need for improved facilities.
In recent years we have seen tremendous losses of stock over vast areas of Africa due to drought. It is probable that such catastrophes will always be with us but it behoves us to consider how they can be alleviated from local resources.
One of the main troubles in an overgrazed area is that there is no fodder reserve for times of need. I am now thinking of certain areas of natural grassland in the northern part of the Somali Democratic Republic that have a mean annual rainfall of no more than 250 mm, which of course means that in most years the rainfall is well below this figure. Accounts written by travellers some 80 years ago describe what the vegetation was like then, giving the local names for the grasses so that we know not only the height but also the species that were growing. The dominant grasses were perennials large enough to hide rhinoceros, but today there is only a patchy cover of annuals. I first saw these areas 25 years ago, and at that time smaller perennials still persisted. The grass cover of other nearby grasslands has now been so reduced that they have been invaded by unpalatable species of Acacia.
It is those areas which have proved their capacity to remain as grasslands even under the heaviest grazing pressure that I consider should be closed to grazing and managed, possibly by some type of cooperative, to produce fodder. It is needed in these areas not only as a reserve against hard times but also to support stock en route to export markets. Small amounts of fodder are at present produced in unauthorised enclosures, which at least illustrates that the fodder would find a ready market.
The advantage of such a scheme would be that the natural grasslands would be preserved in such a way that they could produce much more than they do now, and secondly and perhaps even more important, their management would create new jobs on the range other than that of grazier.
A serious result in many heavily overgrazed areas is a marked increase in the proportion of the vegetation which consists of non-palatable woody species. In certain areas Dichrostachys grows so densely that neither man nor grazing stock can walk through it. It is quite clear that such species should be removed in order to give more palatable species a chance to colonise the areas that are cleared. Such a programme of selective clearance is normally very expensive, and the problem is to find a method which makes this kind of project economically possible. Charcoal can, however, be made from the thin wood that is typical of the invading woody species, but properly designed kilns and trained personnel are required. It should be possible to devise a scheme whereby an area which contains a high proportion of unpalatable woody species could be closed to grazing, and the right to make charcoal from designated species granted to a licensed charcoal burner. The area should remain closed, probably for at least a year, after the charcoal making has been completed, in order to allow the vegetation to recover before grazing starts again. I well realise that even under ideal conditions only small-sized charcoal will be produced, but in these times even small charcoal is likely to find a ready market.
I think that in this discussion we should consider the merits not only of different plant species but also of different animals. The cow is usually regarded as the hub of the grazing world, but goats, sheep and camels all have a valuable role to play. The camel has the great advantage of being able to go a long time without water; it is also a load carrier, and it is this animal that makes the nomadic life possible in the driest parts of Africa. Goats and sheep need water every few days; but the goat does well on a mixture of grazing and browsing, whereas sheep do better on grasslands. In many areas overgrazed by sheep there has been a serious reduction in the proportion of grass on the rangelands, and thus it is now clear that the goat is the appropriate animal to make the best use of the new vegetation. This will, I dare say, come as a surprise to some of you, as the goat in many countries has acquired a reputation for being a great destroyer of vegetation. However, if such rangelands can be improved, the pendulum may swing once again in favour of sheep. Cows need water every second day or so, and are therefore poor nomadic animals. The provision of permanent water by bore holes has increased the number of cows in areas which basically cannot be regarded as suitable for them, and this has resulted in very heavy overgrazing in many areas.
In Africa the rangelands are also often the source of the materials needed to build houses. All too frequently the best species for this purpose are palatable to browsing animals such as goats and camels. It would therefore seem that it might be beneficial for the range and useful in creating jobs to establish areas for the growing and the controlled cutting of such species. It is possible that rising transport costs may now make such projects economically viable. Research should perhaps be encouraged in the use of other types of construction. Such subjects (like meat marketing, which I mentioned earlier), are not within the scope of a rangeland surveyor, but if he sees that the collection of building materials is having an adverse effect on the rangeland vegetation he should consider making general recommendations on this subject.
One of the subjects of this seminar is " sampling and data processing " and the " format of records. " I find these subjects well worth study, and if perfect systems could be devised they would enable the relatively inexperienced surveyor to make a more valuable contribution. However, I would like to add a word of caution. Despite the usefulness of such systems, I think the ecologist or surveyor should always keep his eyes open for the unusual which always tends to get missed by any standardised system. In eastern Africa, there are so-called vegetation arcs, and in West Africa there are large areas of brousse tigrée. Many papers have been published as to how these formations have come to be, but in essence they consist of an area of vegetation which is particularly rich owing to the additional water received as run-off from an adjacent barer area. These arcs are very conspicuous in air-photographs, but on the ground look little more than unevenly distributed areas of denser vegetation. In fact they represent one of nature's responses to overgrazing. Such an observation could suggest to the ecologist that in rangeland improvement he might do well to consider the possibility that on those soils which encourage the surface flow of water, he should be content with the improvement of a proportion of the range rather than all of it. I feel that an interesting phenomenon like this, requiring some investigation, provides an example of what might be missed in a standardised system. We must retain a degree of flexibility in our approach.
I would like to end by quoting a well-known adage of desert warfare, that is: " If you control the water, you control the desert." We cannot control the rainfall but we can do much to control the use that is made of the water once it is on the ground, and we can, of course, control the construction of wells and the supply of well water.