bluuebunny/crossref_metadata_2025 huggingface dataset:
Mapping protein electron transfer pathways with QM/MM methods
Authors: Guallar Victor , Wallrapp Frank
Published: April 2008

Mixed quantum mechanics/molecular mechanics (QM/MM) methods offer a valuable computational tool for understanding the electron transfer pathway in protein–substrate interactions and protein–protein complexes. These hybrid methods are capable of solving the Schrödinger equation on a small subset of the protein, the quantum region, describing its electronic structure under the polarization effects of the remainder of the protein. By selectively turning on and off different residues in the quantum region, we are able to obtain the electron pathway for short- and large-range interactions. Here, we summarize recent studies involving the protein–substrate interaction in cytochrome P450 camphor, ascorbate peroxidase and cytochrome
c
peroxidase, and propose a novel approach for the long-range protein–protein electron transfer. The results on ascorbate peroxidase and cytochrome
c
peroxidase reveal the importance of the propionate groups in the electron transfer pathway. The long-range protein–protein electron transfer has been studied on the cytochrome
c
peroxidase–cytochrome
c
complex. The results indicate the importance of Phe82 and Cys81 on cytochrome
c
, and of Asn196, Ala194, Ala176 and His175 on cytochrome
c
peroxidase.
A stochastic dynamical systems view of the Atlantic Multidecadal Oscillation
Authors: Dijkstra H.A , Frankcombe L.M , von der Heydt A.S
Published: April 2008

We provide a dynamical systems framework to understand the Atlantic Multidecadal Oscillation and show that this framework is in many ways similar to that of the El Niño/Southern Oscillation. A so-called minimal primitive equation model is used to represent the Atlantic Ocean circulation. Within this minimal model, we identify a normal mode of multidecadal variability that can destabilize the background climate state through a Hopf bifurcation. Next, we argue that noise is setting the amplitude of the sea surface temperature variability associated with this normal mode. The results provide support that a stochastic Hopf bifurcation is involved in the multidecadal variability as observed in the North Atlantic.
Introduction. Stochastic physics and climate modelling
Authors: Palmer T.N , Williams P.D
Published: April 2008

Finite computing resources limit the spatial resolution of state-of-the-art global climate simulations to hundreds of kilometres. In neither the atmosphere nor the ocean are small-scale processes such as convection, clouds and ocean eddies properly represented. Climate simulations are known to depend, sometimes quite strongly, on the resulting bulk-formula representation of unresolved processes. Stochastic physics schemes within weather and climate models have the potential to represent the dynamical effects of unresolved scales in ways which conventional bulk-formula representations are incapable of so doing. The application of stochastic physics to climate modelling is a rapidly advancing, important and innovative topic. The latest research findings are gathered together in the Theme Issue for which this paper serves as the introduction.
Rapid diagnostics: the detection of neuraminidase activity as a technology for high-specificity targets
Authors: Shimasaki C. D. , Achyuthan K. E. , Hansjergen J. A. , Appleman J. R.
Published: April 2008

The accurate detection of influenza by clinical symptoms is challenging since multiple pathogenic viruses and bacteria mimic similar symptoms in a patient. With new and more effective influenza therapeutics available, there is a growing need for highly accurate and rapid diagnosis of influenza, particularly when the window of opportunity for proper treatment is measured in hours. A parallel technology, which is also used in the treatment of influenza, was developed for the rapid diagnosis of influenza by exploiting the enzymatic activity of influenza neuraminidase. This technology, which is called Pathozyme, offers the high specificity inherent from the conservation of the neuraminidase active site. The ZstatFlu test uses a small molecule derivative of sialic acid chemically coupled to a reporter group together with simple point–of–care reagents for directly detecting influenza from a patient specimen with high specificity. A second–generation platform technology using this neuraminidase detection system coupled with a more sensitive chemiluminescent reporter has been developed and formatted for reading on high–speed instant film. This modification resulted in a platform technology many–fold more sensitive than the former while maintaining its inherent high specificity. Preliminary data from a prototype tested during the mild 2000–2001 influenza season demonstrated that an optimized chemiluminescent test system could approach the accuracy of 14 day viral culture in a convenient 10–20 min test. This platform technology is currently being explored for the rapid detection of other pathogenic organisms where sensitivity, specificity and speed are essential in a point–of–care setting.
THE ELEPHANT PROBLEM AT TSAVO
Authors: Glover J.
Published: April 2008

Summary

The damage caused by the overcrowding of elephant after several years of drought in the Tsavo National Park has prompted the study of the number and distribution of the elephants within its confines and the possibly “safe” carrying capacity.

Aerial surveys show that the population of the Park is not static and that as many as 10,000 elephants may be found there at certain times. Nearly all the animals are found within some 15 miles of permanent water supplies where damage is greatest. Not all the damage is caused directly by the animals: some, probably the most permanent, is caused by fires which sweep over the regenerating vegetation becoming increasingly devastating as the woody vegetation recedes.

The East Park, the largest part, may be able to carry some 5,000 animals in moderate safety.
FIELD IMMOBILIZATION OF YOUNG WILDEBEEST WITH SUCCINYLCHOLINE CHLORIDE
Authors: Orr D. J. C. , Moore‐Gilbert S. M.
Published: April 2008

Summary

The results of 112 cases of field immobilization of wildebeest, Gorgon taurinus hecki (Neumann), * with succinylcholine chloride are given, and compared with the results given by Talbot and Lamprey (1961), who reported field dose rates of 0.023 mg/lb. body weight as ineffective, 0.028–0.029 mg/lb. as effective, and 0.036 mg/lb. as lethal, when given to adult wildebeest. Doses in the present series were determined empirically in the field and it was found that the youngest age group of wildebeest tried with the drug (49 cases, 6–12 months old) survived ‘lethal’ doses of 0.036–0.037 mg/lb. Field experience suggested that not only were young wildebeest capable of surviving greater doses of succinylcholine than adults, but there was an absence of secondary complications. Adult animals suffered from regurgitation of ruminal contents and difficulty with breathing.

In the field it proved easier to produce consistent results with young wildebeest, and it is suggested that in testing the possible use of succinylcholine for immobilizing other game animals the effect of the drug on both young and old animals should be compared.

Use of an effective marking method, by branding, followed by field recording of marked animals has shown that six animals out of a total of 87 disappeared shortly after release. The casualty rate associated with the field marking is given.
SOME NOTES ON THE BEARING OF YOUNG AFRICAN ELEPHANTS
Authors: Bellinge W. H. S. , Woodley F. W.
Published: April 2008

Summary

In October, 1963 an attempt was made to rear a very young elephant calf, during which time numerous difficulties were encountered. The basic problem was the lack of any available notes and data from experiences of other attempts, which would have been invaluable to us.

The following observations on diet and management, are taken from the detailed diary kept during the attempt to rear “Kasigau”, the young elephant referred to above, and also the well‐known “Eleanor”, for the benefit of those who may, one day, find themselves confronted with a helpless orphaned elephant and may wish to make an attempt at rearing it.
SOME PRINCIPLES OF TSETSE CONTROL AND LAND‐USE WITH EMPHASIS ON WILDLD7E HUSBANDRY
Authors: Lambrecht Frank L. , Hooper G. W.
Published: April 2008

Natural animal populations are adapted to and in equilibrium with their natural environment. Sudden changes in composition of flora or fauna of climax communities may cause serious consequences and even the collapse of the system. This is especially true in Africa where shallow soil and precarious energy cycles are easily upset. With this in mind, it is suggested that serious consideration be given in tsetse‐control schemes and land‐use plans to the feasibility of game‐farming, especially when marginal lands are involved. It would be advantageous in many instances to keep all large and some smaller tracts of marginal lands for wildlife conservation purposes; the large areas as national parks and as a valuable source of government income and prestige, the smaller areas as a permanent animal‐protein supply through game‐harvesting operations. The advantages of game‐farming over domestic livestock‐raising are discussed in detail. A schematized tsetse‐control plan is also presented as an example of land‐use in savannah tsetse belts.
THE VALIDITY OF CENSUSING BLACK RHINOCEROS POPULATIONS FROM THE AIR
Authors: Goddard John
Published: April 2008

The efficacy of censusing black rhinoceros (Diceros bicornis Linnaeus) populations from the air was tested. Repeated aerial counts were made of the black rhinoceros population centered on Qlduvai Gorge, Tanzania, where the number of rhinoceros on the ground is known accurately. Even under the most ideal conditions only 50% of the population was detected by observers in an aircraft, and factors accounting for this are considered. It is concluded that the light aircraft is of limited value in providing estimates of black rhinoceros populations, and estimates based purely on aerial counts are subject to considerable variation.
FOOD PREFERENCES OF TWO BLACK RHINOCEROS POPULATIONS
Authors: Goddard John
Published: April 2008

Food preferences of two discrete black rhinoceros (Diceros bicornis L.) populations were studied in northern Tanzania from 1964–1966 Feeding rhinoceros were watched for a period of one hour, and the plants which they selected and rejected were identified, either as they were feeding or when they had moved on. A technique was used which provided an indication of the relative importance of certain plants in the diet. Observations were made in six different habitat types used by the rhinoceros during the wet and dry seasons. A total of 307 hours was spent actually watching feeding rhinoceros. During this period they were observed eating 191 plant species from 49 botanical families. In all habitat types rhinoceros consume a wide variety of the spectrum of plants available, but are highly selective for herbs and shrubs. At certain periods of the year stenophagous characteristics are apparent, and the species shows a marked preference for legumes. Grasses make up a small proportion of the diet.
APPLIED TOPOGRAPHIC‐ANATOMICAL STUDIES OF EAST AFRICAN GAME RUMINANTS
Authors: Hofmann R. R. , Scholz P.
Published: April 2008

The topographic relationships of the so‐called “vital centres” like the spinal chord brain, heart and major blood vessels of East African game ruminants are discussed, using the impala and the buffalo as type animals for a series of diagrams. Anatomical conditions in relation to the effect of shots in the various body regions are demonstrated with the aim of reducing irresponsible and painful wounding of game animals. Investigations and diagrams are based upon material from 59 animals of 18 species; of these, 47 animals were formalin‐fixed and dissected in a natural standing position.
AGE CRITERIA AND VITAL STATISTICS OF A BLACK RHINOCEROS POPULATION
Authors: Goddard J.
Published: April 2008

Tsavo National Park, in Kenya, probably contains the largest population of black rhinoceros (Diceros bicornis (L.)) left in existence. Large‐scale damage of the vegetation initiated by elephants and aggravated by fire has changed considerable areas of the park. The ecology of the black rhinoceros in this changing environment has been studied; the present status and population structure is considered here, including the development of detailed ageing criteria for the species, an analysis of natural mortality and survivorship, and a record of the structure of the living populations within the major habitat types.

Crania and mandibles were collected from 506 rhinoceros found dead in all areas of the park. This material was divided into 20 relative age classes based on dental characteristics. Crude chronological ages, based on an estimate of the maximum expectation of life and the examination of seven known‐age dental records of captive animals, were assigned to each age class. These crude ages were then refined by examination of 16 dental records of known‐age wild rhinoceros, and a chronological age scale established.

A survivorship curve of the population was thus constructed. Annual mortality during the first and second year of life is about 16%, and the indicated mean annual mortality from 5–25 y is 9.8%. A theoretical model of the population structure is shown, and analysis of the annual mortality and recruitment at birth suggests that the population was stable during the 1960's. Assuming the data represent a stable population the mean expectation of life at birth is 8.4 y.

Thirteen major habitat types are described. The characteristics of the rhinoceros population within each habitat type were established both from ground studies and aerial observations. Nearly 700 rhinoceros were identified and catalogued on the ground, in sample areas selected for intensive study. Population structures, cow: calf ratios, and recruitment appear to be average in most habitat types. The analysis of recruitment at birth and mortality during the first year of life, both from computations from the survivorship curve and from the structure of the living populations, support the validity of the ageing criteria, and further suggest that the population was stable during the 1960's.

Finally, the relationship between the elephant and the rhinoceros in the changing environment is discussed with reference to recent findings in elephant ecology. In conclusion it is recommended that population reduction of the Tsavo elephants should be initiated.
ELEPHANTS AND HABITATS IN NORTH BUNYORO, UGANDA
Authors: Laws R. M.
Published: April 2008

The paper is concerned with the changing relation between elephant populations and vegetation in north Bunyoro, Uganda.

The history of the area over the past 100 years is briefly described, particularly in terms of changing human populations and contraction of the elephant range. The main features of the environment, including vegetation types and distribution, annual burning, other species of large mammals (including the results of aerial counts) and birds are described.

The main results of investigations on the elephant populations in the area, dealing with numbers, distribution and movements, population density distributions, and social organisation iocluding group size frequencies and structure, are presented. From a population of about 10,000 elephants over 1,000 have been cropped or shot on control in the area since 1965. The results of detailed analyses of material derived from these operations are presented and discussed. Material from the cropping operations represents a cross‐section of the population and all animals sampled have been aged from the dentition.

It is concluded that the mean daily food intake (wet weight) is 4% of live weight for all classes except lactating females; results of studies of food quality are discussed and a possible explanation for the de‐barking of trees presented. The physical condition of elephants in several populations has been compared and appears to be poorer when less browse is available. Growth equations are presented for height and weight; the male shows a post‐pubertal growth spurt. Various reproductive parameters are examined including age at puberty, pregnancy rate, and the seasonal cycle. Seasonal conceptions are delayed in North Bunyoro in relation to their timing north of the River Nile and it is suggested that the delay is nutritionally‐induced. Recruitment has been falling in this population and this decline is likely to continue in the absence of effective management. Some undesirable consequences of extensive control‐shooting are mentioned.

The analysis of the elephant populations indicates that they are at densities in excess of the carrying capacities of the habitats, and the continuing changes in these habitats are described. In the grassland and wooded grassland areas the destruction of woodland has progressed radially, a zone of damage about 15–20 km wide having moved outwards through the range. This is consistent with destruction mainly by elephants rather than by fire. The influence of elephants on the forest edge and on the areas of regeneration inside the forest, created by management, is described.

Finally specific proposals that have been presented to the National Parks and Forest Department are discussed. These involve rational cropping of over 4,000 elephants over the range and the construction of elephant‐proof barriers, the control of fire, and the declaration of a Conservation Area with a statutory Authority on which the various interests concerned would be represented.
THE EFFECT OF COMPLETE REMOVAL OF HIPPOPOTAMUS ON GRASSLAND IN THE QUEEN ELIZABETH NATIONAL PARK, UGANDA
Authors: THORNTON D. D.
Published: April 2008

Summary

Coincident 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

Summary

Night 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

(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

In 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

During 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

Long 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

Observations 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

The 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

Censuses 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

The 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

Aerial 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

A 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

This 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

(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

The 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

Impala 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

Aspects 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

Analysis 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.
The density and biomass of large mammals in Lake Nakuru National Park
Authors: KUTILEK M. J.
Published: April 2008

Over the past 70 years, human activity has severely limited the diversity and movements of large mammals in the region of Lake Nakuru National Park, Kenya. Game counts were begun in April 1970 to assess the status of those species remaining. The density of large mammals per km2 was found to be 64.20±8.86 (mean ±S.D.) and the biomass density of the six major species in kg/km2 was 6298±801. The biomass was most heavily concentrated in the grassland‐woodland area south of the lake. Defassa water‐buck was the dominant species accounting for 76% of the biomass density. The probable reasons for their dominance are: (1) favourable habitat; (2) decreased competition; (3) reduced predation; (4) control of poaching; and (5) non‐migratory habits. Future management may ultimately depend on the relationship of waterbuck to the food resources available.
The pattern of lion predation in Nairobi Park
Authors: RUDNAI JUDITH
Published: April 2008

The feeding habits of lions in Nairobi National Park have been observed between 1968 and 1972.

Nairobi Park is briefly described and the herbivore and predator populations are discussed.

The relationship between the changing status of the prey population for the period 1968‐72 and the feeding habits of the lions is examined and compared with data from earlier years.

Selection ratio (preference ratio) for three of the most important prey species is more closely adjusted to the abundance of these species in the total ungulate population than was the case prior to 1968. Only warthog and eland form an exception. Predation on wildebeest shows the most marked decrease although this species has been increasing during the last 5 years.

Wildebeest, kongoni, zebra and warthog have provided 80% of total kills throughout the study on the basis of numbers killed. On this basis, warthog has the highest preference rating. However, the largest contribution to the lions' diet expressed in kg is by kongoni, followed by zebra, wildebeest, eland and warthog, in that order.

Kongoni and wildebeest contribute most during the first half of the year and zebra and eland during the last 6 months.

Selection for males is significant in zebra and eland and highly significant in kongoni, whilst only in zebra is selection for juveniles evident.
The savanna ecology of Kidepo Valley National Park: The effects of burning and browsing on the vegetation
Authors: HARRINGTON G. N. , ROSS I. C.
Published: April 2008

Between 1947 and 1967 tree frequency was reduced by 30% in the Narus valley, Kidepo Valley National Park. Between 1967 and 1972 a further 50% reduction took place on experimental plots. Elephants were largely responsible. Despite a regeneration potential of c. 200 young trees per ha, very little tree regeneration was observed. Experimental fire treatments and animal–free exclosures revealed that annual burning and the current browsing pressure were independently capable of preventing tree regeneration.

Fire effects were significant in the herb composition of the animal exclosures but less so on the grazed areas. This was attributed to trampling of litter on the grazed areas, which assisted termites in litter removal. Untrampled litter accumulation suppressed Themeda triandra to the benefit of Panicum maximum.

Fire effects on the soil were small and impermanent.
The natural regulation of buffalo populations in East Africa: Introduction and resource requirements*
Authors: SINCLAIR A. R. E.
Published: April 2008

Although it would appear that regulation in animal populations is highly probable, the evidence for it in nature is meagre. The various hypotheses on regulation are outlined in order to point out the critical evidence needed to test them. A population of the East African buffalo has been studied since 1965 with a view to obtaining this information.

The ecological requirements including habitat selection and food selection are described. Using Association analysis the ‘best available’ habitat for buffalo was found to be a combination of riverine grassland and forest. This was most pronounced in the dry season when other habitats became less suitable due to the grass drying out and becoming unsuitable food. The movements between vegetation types were correlated with changes in rainfall and with the area of burnt ground after grass fires. Hence the movements could be attributed to changes in the food supply.

Within the ‘best available’ habitats the buffalo ate grass exclusively but not all grass was food. The most preferred component was the combined grass leaf and leaf base, this being the most nutritious part of the plant. This component was predominant in the diet during the rains but declined to a minimum by the end of the dry season despite the animals' ability to select for it.
Habitat utilization by hippopotamus in the Mara River*
Authors: OLIVIER R. C. D. , LAURIE W. A.
Published: April 2008

The results are presented of a 2‐month study of the Mara River hippopotamus population in the Serengeti National Park and the Maasai Mara Game Reserve. A method for correcting aerial counts of hippos in turbid rivers and based on herd behaviour characteristics is described. There were an estimated 1927 hippos at an average density of 16‐1/km in the area censused. The population became more dispersed and the mean group size decreased from thirty to fifteen after a rise in water level. The value of comparisons between populations in various terms of expression of density, and mean group sizes, are discussed. The amount of day living space, defined as areas preferred or utilizable by hippo during the day, and productivity of the food plants are seen to be very important factors in hippo habitat utilization, and as constraints on population increase.

Hippo use of the habitat and the effects of hippo on the vegetation at various distances from the river were quantified, and a cycle of vegetational changes suggested which may be associated with the effects of hippo grazing and fire in other parts of Africa.

Groups were found to consist of nearly equal numbers of males and females. There was no evidence of territorial behaviour either on land or in the water. A number of observations on social interactions and defaecating behaviour are described and indicate that olfactory communication is very important in interactions between hippos. Hippo society is unstable due to climatic influences, but a dominance hierarchy including males and females exists in the groups. Males appear less firmly attached to groups than females, but a male is normally the dominant animal in a group.