Bibliography: Land Degradation in South Africa project

ECONOMIC ASPECTS

Notes : The aim of the study was to present a case study of the politics of

irrigation farming in the Eastern Cape Province of South Africa. The research

repesents a systematic description of the politics of irrigation of farming as

seen on the scheme. The method used was mostly secondary data reports, and

interactions with established individuals in the area. The findings include: 1.

a decline of the fortunes of the scheme consultancy, and management styles of

members of the scheme led to an increase in the range and nature of demands on

management by the commercial farmer, tribal authority and elite; 2. the

decentralisation of economic authority over irrigated agriculture was expressed

in increasing flexibility on the part of management towards adopting new

approaches; and 3. the loss of consultant control over the scheme occurred at

about the same time that the antagonistic relationship between Lennox Sebe's

government and the majority of Ciskeians began to worsen. This article is

available at the University of Fort Hare library. See also ID ref. no. 2339.

Ref ID : 1087

1122. Holland, P.G. and Fuggle, R.F. Impact of veld management on aloe ferox in

Western Cape Province. South African Geographical Journal 64:83-96, 1982.

Reprint : In File,

Keywords : VELD MANAGEMENT; WESTERN CAPE; POPULATION; FIRE

Abstract : Eight relic stands of Aloe ferox, one of SA's widest ranging and most

common aloes, were studied near Swellendam during 1981. One stand had not been

burned in recent years and had been only lightly grazed by sheep and cattle,

another had been frequently burned and heavily grazed for several years, and the

remaining six stands fell between these two poles. A system for estimating ages

of individuals of A. ferox was developed, permitting demographic analyses of

populations of this species growing under differing conditions of veld

management. Seedlings to 10 years of age appear most susceptible to fire and

mechanical damage, and the most distrubed of the eight stands showed minimal

rates of population recruitment. Older plants, with their greater mechanical

strength and fire resistance, seem less affected: maximum age expectation

(estimated at 140 - 150 years) was the same in each of the eight stands. It is

concluded that even SA's more common plant species face potentially serious

reduction in population size and geographical range under prevailing veld

management practices.

Ref ID : 1427

1123. Holmes, M. The meaning of soil erosion. University of Sydney Publications

in Geography 1:52-90, 1938.

Reprint : In File,

Keywords : SOIL EROSION; EROSION; VEGETATION CHANGE; VEGETATION DYNAMICS;

FARMING SYSTEMS; LAND USE

Notes : The author suggests that, if the vegetative covering was not removed the

soil would not wash away so rapidly, and so he advocates reafforestation

(especially on slopes) and intensive pasturage improvement. It is the wide

spaces and vast tracts of land which tend to cause extensive erosion, although

the general opinion is averse to this theory. If farmers and graziers had

smaller areas to look after they would be able to plan out their land and its

uses more successfully than they do on vast areas, and so they would be able to

control erosion, at least to some extent.

Ref ID : 307

1124. Holmes, M. The meaning of soil erosion (review). South African

Geographical Journal 21:52, 1939.

Reprint : Not in File,

Keywords : SOIL EROSION

Ref ID : 1082

1125. Holmes, P.J. and Marker, M.E. Evidence for environmental change from

Holocene valley fills from three central Great Karoo upland sites. South African

Journal of Science 91:617-620, 1995.

Reprint : In File,

Keywords : KAROO DESERTIFICATION; PALAEOENVIRONMENTS; ENVIRONMENTAL HISTORY

Ref ID : 2151

1126. Howard-Williams, C. and Alexander, W.J.R. Catchment management.

Limnological criteria for management of water quality in the southern

hemisphere. Hart, R.C. and Allanson, B.R. Pretoria:CSIR. 93:1-31, 1984.

Reprint : Not in File,

Keywords : WATER QUALITY

Notes : South African National Scientific Programmes Report no. 93, Council for

Scientific and Industrial Research.

Ref ID : 1004

1127. Hubbard, R.N.L.B. and Sampson, C.G. Rainfall estimates derived from the

pollen content of modern hyrax dung: an evaluation. South African Journal of

Science 89:199-204, 1993.

Reprint : In File,

Keywords : RAINFALL; CLIMATE CHANGE; MICROMAMMALS; ARCHAEOLOGY;

PALAEOENVIRONMENTS; ENVIRONMENTAL HISTORY; DROUGHT

Abstract : Pollen-rich fossil hyrax middens have been used to reconstruct

changes in Holocene Karoo plant cover and precipitation. However, rainfall

estimates depend on a set of untested assumptions that link annual spring-summer

rains to grass/Karoo shrublet ratios in the ground cover and to

Poaceae/Compositae ratios in atmospheric pollen. Here, rainfall, ground cover

and pollen discharge records collected in the eastern Karoo from 1952-55 are

compared. There is a very strong correlation between mean monthly rainfall and

mean monthly grass/Composite ratios in atmospheric pollen. In theory, past

rainfall can be estimated from fossil pollen spectra near the sampling station

by the formula rainfall (mm) = Poaceae/Compositae x 4.6. Applied to monthly

pollen counts from modern hyrax pellets collected from 1989 - 91, this formula

revealed clear seasonal rainfall patterns. Also reflected were the catchment

differences between sampling stations, and contrasting drought conditions during

the two sampling periods. The airborne pollen spectrum was not significantly

altered by incorporation into the dung. Seasonal changes in the concentration

and composition of pollen in the pellets were so pronounced, however, that an

assay of the seasonal mix of pellets in any fossil dung sample is recommended

before calculating prehistoric rainfall from its grass/Composite pollen content.

Ref ID : 457

1128. Hudson, C.A. A regional application of the SLEMSA in the Cathedral Peak

area of the Drakensberg.University of Cape Town. , 1987. Master of Science.

Reprint : Not in File,

Keywords : SOIL EROSION

Ref ID : 1303

1129. Hudson, D.A. South African climate change simulated by Genesis, GMC. South

African Journal of Science. 93:389-403, 1997.

Reprint : In File,

Keywords : CLIMATE; CLIMATE CHANGE

Ref ID : 1154

1130. Hudson, D.A. Southern African climate change simulated by the GENESIS GCM.

South African Journal of Science 93:389-403, 1997.

Reprint : Not in File,

Keywords : CLIMATE CHANGE; MODELS; CLIMATE; SOUTHERN AFRICA

Notes : This paper examines the summer (DJF) and winter (JJA) equilibrium

response of the climate sysetm to an instantaneous doubling of CO2 using the T31

GENESIS general circulation model (GCM) (version 2.0.a). The results are

analysed over southern Africa and the adjacent oceans (90oS to 0o; 70oW to

110oE) in order to evaluate the control simulation and determine the large-scale

response to the CO2 forcing. The GCM has been shown to perform well under

present-day conditions, perhaps with the exception of precipitation, which is

overestimated in the model. In respones to the doubling of CO2, there is a

general increase in surface temperatures over the analysis window, with an

increase of between 2o and 3oC over South Africa, and the temperature

differential between high and low latitudes is reduced during both seasons.

There are increases in sea-level pressures and 500 hPa heights south of Africa

in the mid-latitudes during summer and winter in the 2xCO2 simulation, which is

indicative of a weakening of the westerly circulation in this region. For

winter, there is a reduction in the speed of the 500 hPa winds south of South

africa, whereas in summer there is a weakening of the subtropical jet stream and

an increase in strength of the subpolar jet stream. Specific humidities

increase in response to the increase in CO2 during both seasons, as do the 700

hPa moisture fluxes. For winter, there is greater transport of moisture from

over the Atlantic Ocean towards southern Africa in the 2xCO2 simulation compared

with the control. Mid-latitude cyclone densities are generally found to

decrease in the mid-latitudes and increase in a narrow band surrounding the

Antarctic continent for both seasons in the 2xCO2 simulation. This has been

related to changes in surface temperatures and positioning of the sea-ice

margin.

Ref ID : 622

1131. Hughes, D.A. and Sami, K. Transmission losses to alluvium and associated

moisture dynamics in a semiarid ephemeral channel system in southern Africa.

Hydrological Processes 6:45-53, 1992.

Reprint : In File,

Keywords : HYDROLOGY; RUNOFF

Abstract : Transmission losses through the bed of ephemeral rivers in arid and

semiarid regions can account for a large proportion of the total amount of

runoff generated upstream. Losses have typically been estimated by measuring

discharge at two points in the channel system. This paper presents some results

from a semiarid catchment in SA based on moisture observations of the alluvial

material using neutron probe access tubes. Channel flow in this catchment is a

very infrequent occurrence and consequently presents few opportunities to

observe the processes of transmission loss. Only two events have occurred since

the beginning of observations in this area (3 October and 14 November, 1989).

The available information is far from complete but suggests that some 75 per

cent of the upstream flow in the first event and 22 per cent in the second event

was lost to the alluvial material.

Ref ID : 667

1132. Hulme, M. Rainfall changes in Africa: 1931-60 to 1961-1990. International

Journal of Climatology 12:685-699, 1992.

Reprint : Not in File,

Keywords : CLIMATE; RAINFALL; ENVIRONMENTAL HISTORY; MAPS; STATISTICS

Abstract : It remains common for 1941 - 1970, or even 1931 - 1960,

climatological rainfall normals to be used in applied climate studies in Africa.

Often this is due simply to the easier availability of station means or rainfall

maps for these periods. Such rainfall statistics, however, are unrepresentative

of recent decades, especially the new World Meteorological Organization standard

period, 1961 - 1990. In this paper two independent 30-year rainfall

climatologies are for the periods 1931 - 1960 and 1961 - 1990 and are

constructed on a 5o grid. Differences beteween these two 30-year periods are

determined with respect to mean seasonal rainfall, interannual variability and

rainfall seasonality. Latitudinal profiles of mean seasonal rainfall emphasize

the dominance of reduced Sahelian rainfall in the rainfall changes occurring

over this period. This decline in boreal summer rainfall is shown to be

statistically significant using field comparison statistics. Annual time series

of regional rainfall anomalies for the Sahel, East Africa and south-western

Africa are constructed; these three time series possess quite different

interannual rainfall characteristics. Possible explanations for these observed

rainfall changes are discussed with respect to land cover changes, global sea-

surface temperature patterns, and greenhouse gas forcing.

Ref ID : 397

1133. Hulme, M., Conway, D., Joyce, A., and Mulenga, H. A 1961-90 climatology

for Africa south of the Equator and a comparison of potential evapotranspiration

estimates. South African Journal of Science 92:334-344, 1996.

Reprint : In File,

Keywords : HYDROMETEOROLOGY; RAINFALL; CLIMATE; CLIMATE CHANGE

Abstract : A 1961-90 mean monthly climatology for Africa south of the Equator

was constructed at a resolution of 0.5o latitude/longitude for a suite of eight

surface climate variables: minimum, maximum and mean air temperature; rainfall;

sunshine hours; vapour pressure; wind speed; and rain day (>0.1mm) frequencies.

This climatology was constructed from observed station data distributed across

the region with station frequences ranging from 288 (wind speed) to 916

(rainfall). Over 92% of this data is based on observations between 1961-90 and

over 85% has been supplied by national meteorological agencies from the region.

Additionally, for mean temperature and rainfall, monthly anomalies with respect

to the 1961-90 average have been calculated at the same spatial resolution for

each month from January 1961 - December 1994. This paper describes the dataset

which has been compiled for this work, the interpolation methods which have been

used, together with some assessment of the accuracy of the resulting climate

surfaces. The interpolation of the 1961-90 normals uses elevation, as well as

longitude and latitude, as predictor variables and this enables three climate

surfaces to be constructed for each variable, reflecting the 'minimum', mean and

'maximum' elevation within each 0.5o cell. The interpolation of the anomaly

fields uses a simpler method in which elevation is not considered. These

anomaly time series enable fields of interannual variability to be established

for mean temperature and rainfall. The second part of the paper uses this

climatology to construct fields of mean monthly potential evapotranspiration

(PET) for the region using a number of different calculation methods. A

comparison of the resulting PET estimates highlights significant spatial and

seasonal biases due to differences in climate input variables and in the

theoretical representation of PET. The climatology described and analysed here

is available from the authors for use in climate modelling and the study of

climate change in Africa south of the Equator.

Ref ID : 458

1134. Humphrey, B. Soil pipes in the Kamberg area.University of Natal,

Pietermaritzburg. , 1983. Master of Arts.

Reprint : Not in File,

Keywords : SOIL EROSION; KWAZULU NATAL

Ref ID : 948

1135. Humphrey, W.A. The changed conditions of Namaqualand. Transactions of the

Royal Society of South Africa 14:219-224, 1927.

Reprint : In File,

Keywords : SUCCULENT KAROO; DESERTIFICATION ASSESSMENT; RAINFALL

Notes : The author notes that river valleys and general topography of Little

Bushmanland immediately to the south of the Orange River furnish considerable

evidence relating to the past history of the country, namely (a) that this

portion fothe country representas an extremely ancient land surface; (b) that

the present climatic conditions have probably persisted from very remote times;

and (c) that in earlier times still the rainfall over this area must have been

very considerable.

Ref ID : 1368

1136. Hundleby.J.A.B. A strategy for the reclamation and preservation of

communal rangelands with special reference to cattle herd composition. 1989.

Reprint : In File,

Notes : The author condluces that the failures of the past have come about as a

result of the attitudes, perceptions and traditions of the farmer not being

taken into account. In other words the authorities and those responsible for

past planning have failed to recognise the fact that overstocking, overgrazing

and other pressures on the land are, first and foremost, human related problems.

The attainment of increased offtake through marketing will be realised if higher

production levels are reached and production cost factors introduced. Only then

will traditional farmers begin to regard their stock holdings as a source rather

than a sign of wealth. Production and marketing cannot be allowed to proceed

and develop along separate lines any longer, nor can we allow more of our

rangeland heritage to reach the stage where reclamation is no longer feasible.

Ref ID : 1354

1137. Hundleby.J.A.B. A strategy for the reclamation and preservation of

communal rangelands with special reference to cattle herd composition. 1991.

Reprint : In File,

Notes : The author summarises by saying that the failures of the past have come

about as a result of the attitudes, perceptions and traditions of the farmer not

being taken into account. In other words, the authorities and those responsible

for past planning have failed to recognise the fact that overstocking,

overgrazing and other pressures on the land are, first and foremost, human

related problems. The attainment of increased offtake through marketing will be

realised if higher production levels are reached and production cost factors are

introduced. Only then will traditional farmers begin to regard their stock

holdings as a source rather than a sign of wealth. Production and marketing

cannot be allowed to proceed and develop along separate lines any longer, nor

can we allow more of our rangeland heritage to reach the stage where reclamation

is no longer feasible.

Ref ID : 1378

1138. Hundleby.J.A.B. A strategy for the reclamation and preservation of

communal rangelands with special reference to cattle herd composition.Anonymous

Anonymous Bisho:Ciskei Agricultural Corporation. , 1991.

Reprint : In File,

Ref ID : 1165

1139. Huntley, B., Siegfried, R., and Sunter, C. South African environments into

the 21st century, Cape Town:Human & Rousseau, 1989.pp. 9-127.

Reprint : In File,

Keywords : DESERTIFICATION ASSESSMENT; CONSERVATION; POPULATION

Ref ID : 677

1140. Hurt, C.R. The relationship between range condition score and long-term

stocking rates applied to two vegetation types in Natal.University of Natal,

Pietermaritzburg. , 1989. The objectives of the present study were to evaluate

and to define models currently used to index range condition and grazing

capacity in two vegetation types in Natal. Permanent monitoring sites were

established on farms in the Highland Sourveld (27 sites) and Southern Tall

Grassveld (17 sites) and were surveyed twice during the study period. Sample

sites were ranked along a gradient of short-term grazing intensity. Direct

gradient analysis of abundances of important species, detrended correspondence

analysis (DCA) sample site scores, and range condition index (RCI) suggested

that species composition was not affected by this ranking. Detrended

correspondence analysis of the species composition data suggested that the first

axis represented a gradient of grazing intensity. Range condition indices

calculated using the Benchmark, Ecological Index, Weighted Key Species and

Palatability Methods were highly correlated with DCA eigenvector of sample site

scores (P < 0.01 in all cases). Correlations between the DCA sample site scores

and range condition indices calculated using a modified Key Species Method were,

however, not significant. Direct gradient analysis (using the DCA ranking of

sample sites) of important species abundances resulted in species response

curves similar to trends that have been reported in the literature. Direct

gradient analysis of range condition indices indicated a general decline in

condition with increasing grazing intensity. Range condition indices were

evaluated in terms of their sensitivity in detecting spatial changes in species

composition between sites ranked along the grazing gradient. All methods apart

from the Key Speicies Method were successful in this regard. An evaluation of

the methods for detecting temporal changes in species composition indicated that

changes in RCI were being disguised by the relatively short period between

surveys. The Weighted Key Species Method of indexing range condition was

described, and was found to be quick, simple and amenable to use by monitoring,

planning and farming personnel. Grazing capacity models currently used in

southern Africa were not assessed due to the unreliable stocking data available.

Recommendations were made for the definition of future monitoring programmes in

the moist grasslands of Natal.Master of Science.

Reprint : In File,

Keywords : KWAZULU NATAL; VELD CONDITION; STOCKING RATE; MODELS; MONITORING;

SOUTHERN AFRICA; GRASSLAND

Notes : Abstract in file, and literature review also copied.

Ref ID : 1070

1141. Hurt, C.R. and Bosch, O.J.H. A comparison of some range condition

assessment techniques used in southern African grasslands. Journal of the

Grassland Society of southern Africa 8(4):131-137, 1991.

Reprint : In File,

Keywords : VELD CONDITION; GRASSLAND; SOUTHERN AFRICA

Abstract : Techniques currently used to assess range condition in the grassland

biome of southern Africa are reviewed. The methods were used to calculate range

condition indices from fire-climax and climatic-climax grassland data. These

indices were then used to evaluate each method in terms of sensitivity (i.e. the

detection of spatio-temporal differences in index), index interpretation and

efficiency, bearing in mind the objectives of each technique. The Weighted Key

Species Method and Degradation Gradient Method were found to currently provide

the best indices for assessing range condition. Shortcomings of the techniques

are recognized and suggestions are made for the application of these methods in

different vegetation types.

Ref ID : 1055

1142. Hurt, C.R. and Hardy, M.B. A weighted key species method for monitoring

changes in species composition of Highland Sourveld. Journal of the Grassland

Society of southern Africa 6(3):109-113, 1989.

Reprint : In File,

Keywords : VEGETATION CHANGE; VELD CONDITION; GRASSLAND; MONITORING

Abstract : The use of key species for indexing veld condition in relation to the

fire/grazing impact has potential for monitoring change in the Highland Sourveld

of Natal. Weightings are calculated for previously identified key species. A

weighted-averages approach is used in a modified Weighted Key Species Method of

indexing veld condition. Veld condition indices calculated using the method are

highly correlated with rankings along a previously identified grazing gradient

(r=0,85). Weightings are provided for indicator species that can be generally

used for monitoring vegetation changes in the Highland Sourveld. The method has

the advantage of being able to determine the position of a sample site on a