Bibliography: Land Degradation in South Africa project

that outside the canopy spread of the plant. (5) Plants of different life forms

were associated with one another in three zonal patterns underneath and around a

blackthron plant. (6) The relative transpiration of blackthorn and Anthephora

pubescens exceeded that of other woody and grass plants. Investigations into

the eradication of blackthorn included the use of various herbicides, mechanical

implements and fire. (1) The ester of 2, 4, 5-T mixed with diesel oil was most

effective when applied as basal spray, stump-spray, stem-notch and chemical

girdle treatments. (2) The use of mineral oils (diesel oil or power paraffin)

only, proved effective in killing juvenile blackthorn plants. (3) Effective

root kills of blackthorn were obtained with the use of fenuron pellets or

monuron dissolved in water and applied as basal soil applications. (4)

Disappointing results were obtained from the use of a Holt machine and from a

tractor-operated saw. (5) Burning the basal stems of the thicket growing

blackthorn plant with dung, sawdust or wood fires proved to be highly effective

in producing total kills of the root and top growth of this plant. Burns

obtained from dry grass were effective only in killing the aerial growth of the

plant. The killing action of the effective fire treatments is due to the

destruction of coppice buds (below the burned areas) and to the complete ring-

barking effect obtained from these burns. Certain ecological and other factors

responsible for the encroachment of woody plants in the Molopo area are

discussed. It is pointed out that the mode of the distribution of the various

woody plants in the veld was mainly determined by the structure of the seeds and

pods of these plants. The proneness of certain edaphic conditions to the

colonisation of these areas by woody plants is also illustrated. It is finally

concluded that the problem of bush encroachment is intimately related to the

economics of bush control.

Reprint : In File,

Keywords : BUSH ENCROACHMENT; SAVANNA; CARRYING CAPACITY; LAND DEGRADATION;

NORTHWEST PROVINCE; SUBSIDIES; VEGETATION DYNAMICS; CLIMATE; RAINFALL; FIRE

Ref ID : 2240

767. Donaldson, C.H. Die plek en rol van vuur en meganiese beheer - praktyke by

die voorkoming en beheer van bos. Proceedings of a workshop on bush encroachment

and bush thickening held in Pretoria. Pienaar, A.J.Anonymous Pretoria:Department

of Agriculture and Fisheries. :G1-G6, 1980.

Reprint : Not in File,

Keywords : BUSH ENCROACHMENT

Ref ID : 2241

768. Donaldson, C.H. Omvang van bosindringing in die bosveldgebied van die

Transvaalstreek. Proceedings of a workshop on bush encroachment and bush

thickening held in Pretoria. Pienaar, A.J.Anonymous Pretoria:Department of

Agriculture and Fisheries. :A1-A3, 1980.

Reprint : Not in File,

Keywords : BUSH ENCROACHMENT

Ref ID : 1328

769. Donaldson, C.H. and Vorster, M. Veldbestuur in die Karoo. Weiding: 'n

strategie vir die toekoms.Anonymous Anonymous Pretoria:Departement van Landbou

en Watervoorsiening. :1-28, 1989. 0-621-12073-1.

Reprint : In File,

Keywords : RAINFALL; CLIMATE; DROUGHT; FYNBOS; VELD CONDITION; EROSION

Notes : The Karoo consists mainly of areas situated in the central and western

Cape. It encompasses an extensive area of about 37 million ha, about 30% of RSA

land. It's rainfall measures between 100 to 400 mm per annum, and occurs

chiefly in late summer. The mountainous and western areas are usually also

blessed with some winter rain. The climate is severe with warm, dry summers and

extremely cold winters. Spring is often quite changeable and is marked by dry

westerly winds and severe droughts. The topogrophy, ground and geological

formations are also changeable as is the plant growth. Generally, the ground is

flat, stony and alkaline. Plants consist mainly of a mixture of regrowth, karoo

bushes, grasses and shrubs. The eastern areas of the Karoo consists mainly of

sweet veld. As one moves more in a westerly direction, the grass component

changes progressively to desert grasses eg. Stipagrostis spp. As rainfall

decreases towards the western areas, grass covering decreases and secondary

growth and struggling plants become an important part of plant life. In

mountainous areas, one finds more sour grass species (eg. Merxmuellera spp.) and

fynbos. Due to the low rainfall, changes in topography, ground and geological

formations lead to changes in veld conditions within relatively small areas.

Karoo veld is generally sweet or tasty and can be fed to livestock throughout

the year. Grasses remain sweet and nurturing for a relatively lengthy duration,

while the brush and shrubs give nourishment during winter. The production of

karoo veld is particularly low and variable and the veld is also singularly

vulnerable to overgrazing. The bush component is reasonably stable and

resistant against exploitation compared to the grass component, but it also

reacts relatively slowly to rehabilitation. Farmers must therefore take care

not to exploit this component. The grass component reacts much faster and

damage to this component frequently leads to rapid encroachment by bush. The

relationship between beneficial versus destructive plants is relatively good on

undamaged karoo veld. Unfortunately there are large areas in the Karoo where

this relationship is not healthy and the veld has been badly damaged. The karoo

veld has also been subjected to selective grazing due to the great variation in

palatability of grazing. In addition, erosion has taken its toll particularly

where there is little ground cover. Drought is a general problem especially in

the western areas, particularly in spring and late summer. The problem of

unchecked veld degradation is extremely real in the Karoo. This is usually as a

result of ignorant grazing practices, especially overgrazing. Factors which

contribute to degradation include: droughts, rainfall patterns; and, indirectly,

economic pressures. The veld condition varies generally between reasonable and

weak. Overall, it appears that the western and southern areas are in a worse

condition than are the central and eastern areas.

Ref ID : 290

770. Doornkamp, J.L. and Tyson, P.D. A note on the aerial distribution of

suspended sediment yield in South Africa. Journal of Hydrology 20:335-340, 1973.

Reprint : Not in File,

Keywords : SOIL EROSION; SEDIMENTATION

Ref ID : 1823

771. Downing, B.H. Reactions of grass communities to grazing and fire in the

sub-humid lowlands of Zululand. Proceedings of the Grasslands Society of

Southern Africa 9:33-37, 1974.

Reprint : In File,

Keywords : FIRE

Abstract : A stratified sample of 350 plots was used to record grass species

presence, the physical conditions of grasses and forbs, and to assess grazing

usage. Normal association-analysis of the sample data identified and

characterised the grass communities present which, on a plant successional

basis, were found to be part of a retrogressive sequence induced by increasing

grazing usage and the elimination of veld fires.

Ref ID : 164

772. Downing, B.H. Environmental consequences of agricultural expansion in South

Africa since 1850. South African Journal of Science 74:420-422, 1978.

Reprint : In File,

Keywords : DESERTIFICATION ASSESSMENT; ENVIRONMENTAL HISTORY; AGRICULTURAL

DEVELOPMENT; STOCKING RATE; PRODUCTION POTENTIAL; CULTIVATION; CONSERVATION;

AGRICULTURAL PRODUCTION; SOIL EROSION; EROSION

Notes : Eighty-three percent of the land in SA is used for agricultural

purposes. Some 11% of the agricultural land is suitable for cultivation,

whereas 82% is basically suited to natural grazing only. This paper examines the

hypothesis that environmental degradation arising from these usages in the

recent past is sufficiently serious to have economic and conservation

implications greater than were previously supposed. An attempt is made to draw

together a diversity of information, particularly from government reports, in

order to obtain some ecological perspective of the problem as a whole. A

paucity of environmental and vegetation information for past and even present

times necessitates some extrapolation of information from data on agricultural

production, soil erosion and exotic weeds for purposes of estimating the

environmental trends. These data are open to various interpretations,

especially so in the case of agricultural production where a number of

interacting components, including consumer demand and economic conditions, can

affect production. Such an empirical approach is nevertheless needed if some

assessment is to be made of the important subject of environmental change

because adequate, direct records pertinent to the last 1 000 years are unlikely

to be discovered in the immediate furture.

Ref ID : 291

773. Downing, B.M. Subsurface erosion as a geomorphological agent in Natal.

Tr.Geol.Soc.South Africa 71:131-134, 1997.

Reprint : Not in File,

Keywords : SOIL EROSION; KWAZULU NATAL; GEOMORPHOLOGY

Ref ID : 1343

774. Dransfield, R.D., Williams, B.G., and Brightwell, R. Control of Tsetse

flies and Trypanosomiasis- myth or reality. 1991.

Reprint : In File,

Keywords : AID; POPULATION; RURAL DEVELOPMENT

Abstract : The African trypanosomiases are among Africa's most devastating

diseases. The human disease, sleeping sickness, and the animal disease, nagana,

are caused by typanosomes, protozoan parasites transmitted by tsetse flies,

Glossina spp. Attempts have been made to control tsetse and trypanosomiasis for

over 70 years, supported by ever increasing amounts of foreign aid. Although

progress has been made in the control of sleeping sickness this disease still

persists in many countries. Nagana excludes cattle from many of the potentially

most productive areas of Africa and its major constraint on economic

development. In this paper we review the control of tsetse and tryponosomiasis

in the light of recent progress in our understanding of tsetse population

dynamics, with special reference to the experience gained in tsetse control on a

Maasai ranch at Nguruman in the Rift Valley of Kenya, and make suggestions for

the management and funding of future control programmes in relation to rural

development.

Ref ID : 653

775. Dregne, H.E. Erosion and soil productivity in Africa. Journal of Soil and

Water Conservation 45(4):431-436, 1990.

Reprint : In File,

Keywords : SOIL EROSION; PRODUCTION POTENTIAL; SOUTHERN AFRICA; LAND

DEGRADATION; EROSION; LESOTHO; SWAZILAND; ZIMBABWE; WIND EROSION; MAPS;

POPULATION; SOIL CONSERVATION; CONSERVATION

Notes : Irreversible soil productivity losses from water erosion appear to be

serious on a national scale in Algeria, Morocco, and Tunisia in North Africa; in

Ethiopia, Kenya, and Uganda in East Africa; in Nigeria and northern Ghana in

West Africa; and in Lesotho, Swaziland, and Zimbabwe in southern Africa. Wind

erosion apparently has reduced long-term productivity by more than 50% in parts

of southeastern Tunisia. Some evidence indicates that a number of other

countries have suffered considerable productivity loss also, but the location

and magnitude of the damage cannot be assessed adequately to delineate the areas

on the erosion map. Those countries include Burkina Faso and Niger in West

Africa; Burundi and Rwanda in East Africa; and Madagascar, Malawi, Mozambique,

and South Africa in southern Africa. All have been eroded, sometimes severely,

but the effect on productivity is unclear. Many knowledgeable observers believe

that the erosion map understates the erosion productivity problem. They may

well be correct, but that remains to be shown. Whatever the present situation

is, it seems certain to become worse in the near future because populations are

growing rapidly and there is little evidence that current soil conservation

programmes are effective. Water erosion is the dominant threat to long-term

soil productivity and the ability of humans to feed themselves. Wind erosion is

nearly ubiquitous in the arid regions. Although it has obvious and widespread

off-site impacts on human well-being, its impact on crop growth and potential

soil productivity is largely unknown in economic terms.

Ref ID : 1287

776. Drewers, R.H. and Venter, A.D. Physical planning of veld. Grazing

management a strategy for the future.Anonymous Anonymous Pretoria:Department of

Agriculture and Water Supply. :1-5, 1989. 0 621 11410 3.

Reprint : In File,

Ref ID : 1350

777. Drewes, R.H. and Venter, A.D. Physical planning of the veld.

Pretoria:Department of Water Supply. , 1985.

Reprint : In File,

Ref ID : 1290

778. Drewes, R.H. and Venter, A.D. Physical planning of veld. Grazing management

a strategy for the future.Anonymous Anonymous Pretoria:Department of Agriculture

and Water Supply. :1-5, 1989. 0 621 11410 3.

Reprint : In File,

Notes : The physical planning of veld involves the subdivision of the veld into

camps, the supply and correct placing of watering points and gates and the

provision of passages to allow access to certain camps. It is often thought

that subdivision of the veld into camps is done primarily for better control and

management of different classes of animals on the farm. It is also often

claimed that camps are necessary for the implementation of a system of

rotational grazing and rotational rest. Although these reasons are both valid,

there is a more fundamental reason requiring the veld to be subdivided into

camps, namely that the grazing animal tends to give preference to certain parts

of the veld, giving rise to overgrazing, whilst other areas tend to be avoided

which in turn leads to undergrazing in such areas. It has not yet been

established beyond doubt why animals prefer certain areas and avoid others. It

is also still unknown how the animal manages to select the same area for

preferential grazing. What has, however, been established is that the

palatability of a specific area of veld can be coupled with one or more of the

following environmental features: (1) position in the landscape, that is the

plateau, the slope, the plain or the water course; (2) aspect, that is whether

the slope faces north, south, east or west; (3) slope; (4) parent rock; and (5)

soil form and series. The more these environmental factors vary from place to

place on the farm, the greater will the differences in palatability of the veld

be. It is correct to state therefore that on farms where the topography is

broken and/or parent rocks vary considerably, substantial differences in

palatability will occur. On the other hand, on a farm where the topography is

fairly flat and/or the parent rocks are the same over large areas, no marked

differences in palatibility will be apparent.

Ref ID : 1295

779. Drewes, R.H. and Venter, A.D. Fisiese beplanning van die veld. Weiding 'n

strategie vir die toekoms.Anonymous Anonymous Pretoria:Departement van Landbou

en Watervoorsiening. :1-6, 1989. 0 621 11409 x.

Reprint : Not in File,

Ref ID : 1382

780. Dreyer, L. The dynamics of community non-compliance with basic water

supply.Anonymous Pretoria:Water Research Commission. TT93/98:1-57, 1998.

Reprint : In File,

Notes : This research studied the problem of non-compliance for payment of

water, from the perspective of community members. A number of projects were

studied to this end. A research team comprising the project leader and a lady

familiar with the language and customs of each province visited villages in

which the projects were situated, unannounced. Conversations were conducted

with ordinary villagers, village leaders and water committeees on water matters,

including the project. Men and women, individually and in groups, were spoken

to. The research team was received in a friendly manner by the villagers who

were all very willing to talk about the matter. The results of the research

pointed to problems with the conceptualisation of the national water rural

community supply initiative. The water supply programme was designed to provide

each household with 25 litres of clean water per person per day within 200

metres. This is intended to meet the basic water needs of the villagers and for

which they are to pay operations and maintanance costs. In the projects studied

here, agreements were negotiated with elected community representatives (who

comprise a water committee) while community members were trained to manage the

projects as well as the ultimate water scheme. The research found that many

communities already had their basic needs for water met, and wanted a higher

level of service than the national water supply programme envisaged. The

projects that were successful, were situated in villages with a dire need for

water and who benefitted appreciably from the project. When the communities

that felt their basic need for water was already satisfied (even if it was not

clean water), or found that their expectations for a higher level of service

(which they interpreted as a tap in their own yards) would not be met, they

withdrew their payments. The collapse of water projects did not happen simply

and directly. There were usually other problems during implementation which

were manifest reason for project failure, but which the water committee or

community in general could not find enough enthusiasm to resolve, probably

because they did not really need the water. The second problem regarding the

conceptualisation of the water delivery programme, is the assumption that

community cohesiveness is a valid basis for the election of a water committee

with whom outsiders can negotiate and conclude agreements. The research cast

doubts on this assumption. In the cases where there did appear to be

significant community cohesion, the cohesion itself was sometimes the last straw

leading to the collapse of the project. In these cases, the community preferred

to abandon the project rather than risk internal conflict over water matters.

Within the projects themselves, there were a number of reasons for project

failure. These are: weak community leadership, lack of communication between

the water committee and the community, lack of project management expertise,

impatient and ill-advised engineering consultants, unequal benefits from the

water scheme to community members, projects proceeding without contributions

from all community members, no means of forcing community members to pay, multi-

village schemes which are too difficult for water committees to manage, a low

level of service, unwillingness to give money to fellow villagers, and the role

played by organisations such as SANCO and the ANC Youth League. Affordability,

although used as an excuse, did not appear to be the real reason for community

non-compliance with projects. The report recommends that the national water

initiative be adjusted to provide for a higher level of service where

communities feel their basic need for water has already been met. This would

entail taps in each yard where the water source can support this. Users should

pay towards the higher level of service as well as the operations and

maintenance costs, preferably by prepayments. Porjects should be undertaken

with community consultation and include some kind of provision for the indigent.

Ref ID : 527

781. Drummond, J. Towards a geography of development for the rural periphery.

In: Geography in a changing South Africa, edited by Rogerson, C. and McCarthy,

J.Cape Town:Oxford University Press, 1992,p. 265-280.

Reprint : In File,

Keywords : AGRICULTURAL DEVELOPMENT; COMMUNAL AREA

Ref ID : 1888

782. Du Pisanie, A.L. Klimatologie - hoe beinvloed die klimat die

boerderybedryf. Veld Trust Conference on the conservation status of agricultural

resources in the RSA. Du Preez, J.F.Anonymous Pretoria:Unisa. , 1990.

Reprint : In File,

Keywords : CONSERVATION

Notes : This article describes the importance of taking weather into account

before deciding what type of farming is suited to specific areas. It is also

shown that climatology may be used to assist farmers make sound managerial

decisions, both for the medium- and long-term. Climatology offers people an

excellent opportunity to work with nature, rather than against it, and so

prevent costly mistakes being made.

Ref ID : 2210

783. Du Plessis, H.M. Water quality and irrigation in South Africa.Anonymous

Water Research Commission. , 1998.

Reprint : Not in File,

Keywords : WATER QUALITY; IRRIGATION

Ref ID : 2134

784. Du Plessis, H.M. and Van Veelen, M. Water quality: salinization and

eutrophication time series and trends in South Africa. South African Journal of

Science 87:11-16, 1991.

Reprint : Not in File,

Keywords : WATER QUALITY; SALINIZATION

Ref ID : 1449

785. du Plessis, M.A. The effects of fuelwood removal on the diversity of some

cavity-using birds and mammals in South Africa. Biological Conservation 74:77-

82, 1995.

Reprint : In File,

Keywords : BIODIVERSITY; DEFORESTATION; EASTERN CAPE; FOREST; ENERGY; PLANT-

ANIMAL INTERACTIONS

Abstract : Although the sustainability of the woodfuel resource has been the

cause for concern in many developing countries, few studies have considered the

impact of fuelwood utilisation on biota other than trees. In this study, I show

that in the eastern Cape Province, South Africa, the increasing removal of dead

wood over less than a decade negatively affected the diversity of cavity-using

vertebrate species. More specifically, this study provides evidence that, in

South African riverine forest habitats, cavity-using forest-edge species, and

species that are limited to making holes in soft-wood substrata, may soon

disappear from utilised areas. It may be shortsighted to consider the

sustainability of the fuelwood resource in isolation of the protection of

biodiversity. This study serves to point out the dangers of overlooking the

effects of fuelwood utilisation practices.