bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE EFFECT OF COMPLETE REMOVAL OF HIPPOPOTAMUS ON GRASSLAND IN THE QUEEN ELIZABETH NATIONAL PARK, UGANDA
Authors: THORNTON D. D. 
Published: April 2008

SummaryCoincident with the shooting out of hippopotamus in May 1958 20 permanent 30.46 m line intercept transects were established on the denuded grassland of the Mweya Peninsula, Queen Elizabeth National Park, western Uganda, to assess botanical changes in basal cover, species composition and frequency. Between May 1958 and May 1959, grass basal cover (GBC) decreased from 14.7% to 5.3% and bare ground increased from 78.3% to 83.6%. After four years total ground cover was 10.9% GBC, 27.2% litter, 1.3% dicotyledons and 60.6% bare ground.Changes occurred in grass species composition. The perennial carpet grass, Chrysochloa orientalis, declined from 37.7% GBC (transect frequency 100%) to 6.6% (87%) by May 1962. Bunch grasses showed marked recovery: Sporobolus pyramidalis increased from 8.0% GBC (60%) to 27.6% (100% frequency). Cynodon dactylon, initially prominent in two lakeside transects only, declined from 9.2% GBC to 2.1%, then became re‐established in inland localities and recovered to 11.7% GBC.The variable rainfall (714 mm annual average) and its influence on plant growth is discussed and the advantage of mechanically increasing effective rainfall mentioned. Authorities for plant names are given in Table 3.
NIGHT COUNTS OF HARES AND OTHER ANIMALS IN EAST AFRICA
Authors: ELTFUNGHAM S. K. , FLUX J. E. C. 
Published: April 2008

SummaryNight counts of hares and other animals were made on a disused airstrip in the Queen Elizabeth National Park, Uganda and on the road between Magadi and Nairobi in Kenya. Lepus crawshayi is the only species of hare which occurs in the Queen Elizabeth Park but L. capensis is also found in Kenya. No regular seasonal fluctuations were found in the number of hares recorded due probably to the continuous breeding of these equatorial species. The number of waterbuck seen in Uganda on moonlit nights was significantly greater than that counted on dark nights. This is not thought to be due to better viewing conditions under a full moon since the phenomenon was not found with other species. The number of hares recorded varied inversely with the number of other mammals present but bore no relationship with the number of birds. It is concluded that night counts can be useful in revealing population trends but not for assessing total numbers or for comparing densities in different areas.
An investigation of some sources of bias in aerial transect sampling of large mammal populations
Authors: PENNYCUICK C. J. , WESTERN D. 
Published: April 2008

Summary(1) Aerial transect sample censuses were undertaken in the Masai Amboseli Game Reserve, counting several species simultaneously. The following comparisons were made between different variants of the census technique:(a) Flying height–500 ft (152 m) versus 300 ft (91 m).(b) Strip‐width–371 m versus 197 m.(c) Viewing angle–inner versus outer half of the wide strip used in (b).(2) In each comparison, transects representing the two treatments to be compared were randomly interspersed. Two population estimates, with variances, were obtained for each species, one for each of the treatments being compared.(3) A rf‐test was used to see whether the two estimates for each individual species differed from each other. In addition, a Wilcoxon matched‐pairs signed‐ranks test was applied to the complete list of pairs of estimates, obtained from each comparison of treatments.(4) Significant differences were found, indicating that the low flying height gave bigger estimates than the high, and that the narrow strips gave bigger estimates than the wide. No difference was found between the inner and outer strips.(5) Measurements of variations in the aircraft's angle of bank were made in smooth and in rough air. The amount of upward bias attributable to this source was estimated for the combinations of height and strip‐width used, and a general formula is also given, from which this bias can be estimated for other combinations.(6) A flying height of 300 ft (91 m), and a strip‐width of 300 m were finally selected as most suitable for multi‐species counts in the partially‐wooded habitat of Amboseli.
The use of drinking sites, wallows and salt licks by herbivores in the flooded Middle Zambezi Valley
Authors: JARMAN P. J. 
Published: April 2008

SummaryIn the unflooded Middle Zambezi Valley, water was available for drinking in zoogenous pools in the deciduous woodlands of the escarpment hills only during, and for a short period after, the rains. For 5 or 6 months each year these pools were dry. During the dry season the majority of large mammals drank either from remnant pools in stream beds, or migrated to the Zambezi flood plain where water was available in the Zambezi River and in pools on the flood plain. In the part of the valley filled by Lake Kariba the Zambezi and its flood plain have been inundated, and the lake shore now lies permanently in the deciduous woodlands of the escarpment hills. Although the former riverine dry‐season water sources have been removed, new sources are available along the lake shore. The suitability of the shore as a drinking site is affected by its exposure to wave action, its pitch, its soil type, and the vegetation type abutting on it, as well as by the preferences of the species using it. Elephant modify drinking sites on the shore by digging water‐filled holes at the water's edge in clay soil, and elephant, buffalo and rhinoceros create wallows in similar situations. The holes dug by elephant are much used by antelope, especially impala, for drinking. By analogy with elephant‐created pools in the woodlands, these zoogenous pools on the lake shore may have been a source of sodium for species drinking there. Such sources were not widely available in the dry season in the unflooded Zambezi Valley.
Notes on the biology of the giraffe
Authors: FOSTER J. B. , DAGG A. I. 
Published: April 2008

SummaryDuring a 3‐year study in Nairobi National Park, 1965–1968, 250 giraffe were identified by their neck markings. The herd structure of these animals was studied, including the relationships between particular individuals. Population information collected included the times of calving, the growth and longevity of giraffe, their reproductive potential, the age structure of the population and its density. Immigration, emigration and home range studies were completed with the help of radio telemetry equipment. The effect of giraffe on the vegetation and the possibility of giraffe surviving without free water are discussed.
Long term monitoring of mammal populations in the Serengeti: census of non‐migratory ungulates, 1971*
Authors: SINCLAIR A. R. E. 
Published: April 2008

SummaryLong term parallel studies on animal populations can give information on problems concerning population regulation, competition and predation. So far only two populations in the Serengeti have been studied in this way. To initiate long term studies on several ungulate species an aerial transect census was carried out in 1971. The methods of counting and the statistical analysis are described in detail so that future workers can repeat the census. The results are presented for impala, topi, kongoni, giraffe, waterbuck, eland and buffalo male groups. Based upon the confidence limits of the samples, it is suggested that the next census be carried out in June 1974.
A comparison of the grazing preferences of buffalo (Syncerus caffer) and Ankole cattle (Bos indicus) on three different pastures
Authors: FIELD C. R. , HARRINGTON G. N. , PRATCHETTJ D. 
Published: April 2008

SummaryObservations of the diet of cattle and buffalo grazing three different pastures of known composition and history were made at the height of the rainy season in Acacia‐Cymbopogon/Themeda dry savanna in Ankole, Uganda. Brachiara decumbens, Chloris gayana, Cynodon dactylon, Digitaria melanochila and Setaria aequalis were frequent species which were highly acceptable to both buffalo and cattle. Themeda triandra was highly acceptable to cattle but less so to buffalo. Leersia hexandra, a swamp grass, was eaten by buffalo but the cattle did not graze in wet areas. Loudetia kagerensis and Cymbopogon afronardus were largely unacceptable to both species of animal, although buffalo showed a greater tolerance of C. afronardus than did the cattle. It is suggested that both species of animal showed a need to vary their diet periodically and buffalo chose C. afronardus whereas the cattle browsed A cacia bushes for this purpose. The quantities ingested were small.Preferences of both species of animal varied with choice available and its physical condition. The pretreatment of herbage by other species of animals is considered important in affecting its acceptability.Cattle and buffalo appeared to be competitive for food in the three environments in this study but the buffalo utilized certain environments e.g. standing water, tree shade, to a greater extent than the cattle and so represented an overall improvement in the secondary productivity from the area.
Daily activity of impala
Authors: JARMAN M. V. , JARMAN P. J. 
Published: April 2008

SummaryThe basic activity pattern of impala in the Serengeti is described quantitatively; seasonal variations and those related to social status are discussed. The adaptiveness of the basic pattern, especially in the preponderance of vulnerable and mobile activities in the daytime and of static activities at night, is discussed. The cost of various territorial activities is stressed; the presence of females in his territory disturbs the basic activity pattern of the territorial male, reducing his time spent on feeding and ruminating. The relationship between the occurrence of males in shade and some environmental factors is analysed.
Population increases of buffalo and wildebeest in the Serengeti*
Authors: SINCLAIR A. R. E. 
Published: April 2008

SummaryCensuses of buffalo and wildebeest in the Serengeti‐Mara region have been carried out by various workers at intervals since 1958. The methods of these censuses, which normally employ a total count, are described and the errors inherent in such techniques are analysed in detail. After the appropriate corrections had been made the results showed that both populations have increased considerably over the years 1961–1971.
The numbers and distribution of buffalo in the Ruwenzori National Park*, Uganda
Authors: ELTRINGHAM S. K. , WOODFORD M. H. 
Published: April 2008

SummaryThe buffalo (Syncerus coffer (Sparrman)) in the Ruwenzori National Park, Uganda were censused by means of aerial survey. Details of earlier censuses of buffalo from the air are given. Herds were located by flying along flight lines 1–6 km apart at a height of 300 m above ground. Buffalo in small herds and in bachelor groups containing less than thirty animals were counted individually but most herds were photographed and the number of buffalo counted from the prints. Two full photographic counts were made in November 1968 and December 1969 and subsequently, counts of herds only were made four times a year during each wet and dry season. The total numbers of buffalo were estimated from the herd counts on the basis of the mean herd size and percentage of bachelors recorded earlier. A total of 17 835 buffalo, comprising 16 749 in 165 herds and 1086 bachelor bulls, was recorded in 1968 and 18 040 buffalo made up of 17 141 in 162 herds and 899 bachelors were counted in 1969. The mean herd size was 101‐5 in 1968 and 105‐8 in 1969 with bachelors representing 6‐1% and 5‐0% of the totals in 1968 and 1969 respectively. The mean size of the bachelor groups was 4–7 and 3‐3 in 1968 and 1969 respectively. The density of the buffalo was the same each year at twelve animals per sq. km. If only the preferred habitat is considered, the density becomes thirty‐eight buffalo per sq. km. The mean areas occupied by a single herd were 9‐4 and 9‐6 sq. km in 1968 and 1969 respectively. The mean area of preferred habitat used by one herd was 2–9 sq. km each year. It is concluded that herd counts are not a satisfactory method for assessing the total buffalo population although they have value as indices, provided the same observer is used. However, they do suggest in the present work that there is a slight but definite seasonal movement of buffalo into forested areas or towards permanent water during the dry season.
The flamingo and pelican populations of the Rift Valley Lakes in 1968‐69
Authors: BARTHOLOMEW G. A. , PENNYCUICK C. J. 
Published: April 2008

SummaryAerial photographic sample censuses of the flamingoes and pelicans on Lakes Nakuru and Hannington were carried out on four occasions between October 1968 and March 1969. On Lake Nakuru the estimated numbers of flamingoes varied between 172 000 and 401 000, and the pelicans between 6800 and 27 900. There were no pelicans on Lake Hannington, but the number of flamingoes varied between 507 000 and 634 000. It was not possible to distinguish between greater and lesser flamingoes, or between white and pink‐backed pelicans on the aerial photographs.On 28–30 March 1969 a census was carried out on twenty‐four lakes, between Lake Hannington in the north and the Singida lakes in the south. The total number of flamingoes seen was just over one million, with 22 000 pelicans.About 100 000 lesser flamingo nests were counted from aerial photographs taken over Lake Natron in November 1969.
The distribution and abundance of marabou storks in Uganda*
Authors: ROY D. E. POME 
Published: April 2008

SummaryA series of censuses throughout Uganda showed that the population of marabou storks between 1970 and 1972 was of the order of 4000–5000 of which the majority were usually in Ruwenzori (formerly Queen Elizabeth) National Park. There were at least twenty breeding colonies totalling some 1300 nests.Marabous have two main types of food. Firstly, there is what might be termed ‘natural food’, such as insects and amphibia, and the poachings from carcasses. This is assumed to have been the only kind of food available to marabous until comparatively recently. The other type is food obtained as a consequence of human activity. In Uganda, the second category is now far more important than the first.The numbers of marabous at three sites are considered in relation to their food supply, and in each case it appeared that there was usually an excess of food. Against this background, consideration is given to those factors which might be limiting to the rate of increase of this species.Marabous have obviously benefited from human activity and have no doubt increased greatly in numbers as a result. Moreover, they are probably still increasing, and it appears likely that they will continue to do so.
Reproductive biology of lions (Panthera leo massaica Neumann) in Nairobi National Park
Authors: RUDNAI JUDITH 
Published: April 2008

SummaryThis study was conducted from June 1968 to July 1969 and from August 1970 to December 1972 with information available for the intervening period as well as for the first half of 1968, giving records for approximately 5 years.The Nairobi Park lion population has averaged thirty animals with a high percentage (about 60%) of juveniles and a preponderance of females among the adults.Matings occurred all through the year but births showed a distinct peak during December and January. The correlation between number of kills one month and births 3 months later proved statistically significant, suggesting that the level of nutrition may influence fertility.Gestation period is about 110 days; litters, when first seen, averaged three cubs, sex ratio was 1:1. Cubs ioined their pride when 6–8 weeks old, but only if no cubs much older than themselves were present; reasons for this are suggested.Young males left their pride around the age of 2 years and so did most young females, although the latter occasionally stay on with their pride.Youngest age to conceive was about 2| years, intervals between litters averaged 2 years. The hypothesis is put forward that lionesses usually refuse to raise single cubs or those that remain sole survivors at less than 3 months of age. Some evidence to support this thesis is submitted.The reproductive performance of the Nairobi Park lions is compared with those in the Serengeti (Schaller, 1972). The Nairobi population's higher performance despite a higher density there suggests that numbers are still within the optimum. However, this balance is dependent upon a large surplus being able to disperse into the area adjo'ning the Park.2
Reproduction in two species of equatorial free‐tailed bats (Molossidae)
Authors: MUTERE FESTO A. 
Published: April 2008

Summary(1) The insectivorous bat T. pumila living at Entebbe latitude 0o6'N breeds throughout the year. However, it exhibits peaks in its breeding cycle which appear to coincide with the two rainfall peaks which occur at Entebbe and in Uganda generally; a low one in October‐November and a higher one in April‐May.(2) The other insectivorous bat T. condylura living at Bukalasa latitude 0o43'N exhibits a bimodal breeding rhythm also closely correlated with the rainfall pattern at Bukalasa which is similar to that at Entebbe.(3) Rain may therefore be an important proximate factor in the breeding of these bats while food (insects) may play an important ultimate role.(4) One young per bat is the rule and implantation which always takes place in the right horn of the bicornuate uterus of both species is unilateral.(5) The gestation period in T. condylura is about 2 months and in T. pumila, it may be shorter than this.(6) Both species develop and mature rapidly and as they are often found living together, the difference in their breeding patterns is advantageous in that it helps to reduce competition between them.
Effects of fishing on the Tilapia nilotica (Linne‘ 1757) population in Lake George, Uganda over the past 20 years
Authors: GWAHABA J. J. 
Published: April 2008

SummaryThe size of the Tilapia nilotica population in Lake George was determined using purse seines. Production, mortality rate, size at maturity, and other parameters of the population were also determined. In Lake George, the factors that regulate the population of T. nilotica are both natural and artificial. The restricted size of nursery zones, strong fish‐killing storms, predation and old age are some of the natural regulators. For the adult population, mortality due to these factors is low (natural mortality coefficient, M=0.1). However, commercial fishing appears to have a stronger controlling force. Since the intensification of commercial fishing in 1950, the size of the fish caught has been decreasing, whereas the number of fish caught has been increasing yearly, probably as a result of increasing effort and the use of small mesh nets. These two trends may be the cause for T. nilotica to mature at a smaller size than they did 15 years ago.
Social behaviour, population structure and reproductive potential in impala
Authors: JARMAN P. J. , JARMAN M. V. 
Published: April 2008

SummaryImpala in southern and eastern Africa differ in the proportion of the year during which adult males are effectively territorial, and consequently in the age at which young males are driven from the female herds. A comparable difference in the age at which male mortality accelerates, relative to female's, suggests that this differential mortality is a product of male‐imposed social organization. In theory this produces enhanced resource flow to females in the population, leading to a greater natality per unit of resource than would be possible without these effects of social organization. It seems that the impala's kind of social organization can not have a density‐dependent regulatory function.
The natural regulation of buffalo populations in East Africa: II. Reproduction, recruitment and growth*
Authors: SINCLAIR A. R. E. 
Published: April 2008

SummaryAspects of the seasonality of breeding, age‐specific fertility, and growth were studied in a sample of animals collected from the Serengeti buffalo population, and compared with two populations in Uganda. Fluctuations in fertility and recruitment were studied by the use of regular aerial photographic samples of herds in the Serengeti. The fluctuations in fertility rate were not related to density and hence could not have regulated the population.Buffalo show a pronounced seasonality in births which is correlated with the quality of ingested food and with rainfall. Since the female has a considerably higher food requirement during late pregnancy and lactation, nutrition is probably an important factor determining this seasonality. Conception does not appear to be influenced by nutrition, for the quality of food remains high throughout the rainy season prior to and during the period of conception. Growth rate, age of first ovulation, and age of sexual maturity do not appear to differ between the Serengeti and Uganda populations. Although there is little difference in fertility between these populations, as measured from the collected samples, little weight can be placed on this evidence, for large fluctuations in fertility can take place from year to year within a population. The fluctuations in the Serengeti population do not appear to be correlated with rainfall, and it is possible that they are random. Fluctuations in recruitment from year to year are also observed. Two sample areas over 100 km apart but within the same population show parallel fluctuations suggesting a similar external influence on the size of the recruitment. This recruitment is not correlated with population size but it may be related to rainfall. Underweight calves at birth have been recorded and this may have been caused by the undernutrition of pregnant females during the dry season through a combination of poor food supply and the demands of the previous lactation.
The natural regulation of buffalo populations in East Africa: III. Population trends and mortality*
Authors: SINCLAIR A. R. E. 
Published: April 2008

SummaryAnalysis is carried out on the population data obtained from censuses and estimates of fertility and recruitment for the years 1965–1972, From the analysis, adult mortality is the only detectable reduction which acts as a negative feedback on the population, and is the only one needed to regulate the population in a way similar to the observed population trends. From a frequency distribution of ages at death, an approximate composite life table is constructed. This shows that males and females have similar age‐specific mortalities until old age, but then males survive relatively better. Information on the causes of mortality indicate that the regulating adult mortality is caused in part by undernutrition, which in turn is due to food limitation rather than to social and physiological factors. Predation causes only a small part of the annual adult mortality, and its effect is swamped by other factors. Diseases play an important part as a primary factor in juvenile mortality but not in adult mortality because of the development of immunity. However, both disease and predation are important as secondary agents killing adults already weakened by moderate undernutrition. It is suggested that they play an essential role by hastening the population's response to changes in the food supply, and hence dampening oscillations that might develop in population and resource.