bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of reduced shrub density and cover on territory size and structure of Kirk's dikdik in Arusha National Park, Tanzania
Authors: BOSHE J. I.
Published: April 2008

Effects of reducing food and cover resources on territory size and structure of Kirk's dikdik were studied in Arusha National Park, Tanzania.

Results show that territory shapes, structure and sizes in Kirk's dikdik vary considerably from one family to another. Comparatively small territory sizes are reported in this work (Mean size = 0.05 ha, SD = 0.02, n= 20). Territories are generally established in the more open areas, and most areas of dense thickets and shrubs are avoided. Reducing shrub density and cover within the territories led to either boundary extension or complete territory abandonment. Such responses by most dikdik families occurred when at least 40% of the total initial shrub density had been removed. These observations are attributable to the concept of economic defendability of territories in animals.

On a étudié dans le Pare National d'Arusha en Tanzanie les effets de la réduction des ressources alimentaires et du couvert sur la taille et la structure du territoire chez le dikdik de Kirk. Les résultats montrent que la forme, la structure et la taille du territoire du dikdik de Kirk varient considérablement d'une famille à l'autre. Des tailles de territoires comparativement faibles sont rapportées dans ce travail (taille moyenne = 0.05 ha, DS = 0.02, n= 20). Les territoires sont établis généralement dans des zones plus ouvertes et la plupart des zones de buissons et arbustes denses sont évitées. La réduction de la densité de buissons et du couvert dans les territoires mène soit à l'extension des limites soit a l'extension des limites soil à l'abandon complet du territoire. Ces types de réponses de la plupart des families de dikdik survinrent lorsqu'au moins 40% de la densité initiale de buissons fut supprimée. Ces observations peuvent être mises en relation avec le concept de ‘defendabilitééconomique’ chez les animaux.
Role of small browsing mammals in preventing woodland regeneration in the Serengeti National Park, Tanzania
Authors: BELSKY A. JOY
Published: April 2008

The effects of fire and browsing on woodland regeneration in the Serengeti National Park, Tanzania were assessed from tree growth data in fire‐ and large‐mammal‐exclusion plots set up in formerly wooded, grassland communities. Plots in each site were (i) browsed and burned, (ii) browsed only, or (iii) neither browsed nor burned. During the 3 years of the study, the mean heights of all tree species were significantly reduced by browsing but fire had little additional effect. Mean tree heights were maintained at < 31 cm for 3 years in the browsed‐and‐burned and browsed‐only plots while increasing to 49 and 78 cm in the neither‐browsed‐nor‐burned plots. Since elephants and giraffe browse primarily above I m in the Serengeti, small browsers such as Grant's gazelle, Thomson's gazelle, dikdik and impala are thought to be responsible for the slow growth rates in the browsed plots.

Les effets du feu et du broutage sur la régénération des zones boisées au Parc National du Serengeti (Tanzanie) furent évaluées à partir des données de croissance dans des quadrats‐échantillon en savane anciennement boisée où le feu et les grands mammiféres étaient exclus. Dans chaque site, les échantillons furent (i) broutés et brûlés, (ii) seulement broutés, ou (iii) ni broutés ni brûlés. Durant les 3 ans de l'étude, les hauteurs moyennes de toutes les espèces d'arbres furent significativement réduites par le broutage mais le feu eut peu d'effet supplémentaire. Les hauteurs moyennes des arbres furent maintenues à moins de 31 cm dans les quadrats broutés‐et‐brûlés et broutés‐seulement, alors qu'elle augmente à 49 et 78 cm dans les quadrats ni‐brûlés‐ni‐broutés. Puisque les éléphants et les girafes broutent avant tout au‐dessus d'l m au Serengeti, les brouteurs plus petits tels que les gazelles de Grant et de Thomson, le dikdik et l'impala doivent être les responsables de cette croissance lente dans les quadrats broutés.
Resource partitioning in a woodland reptile community of the Kafue flats, Zambia
Authors: SIMBOTWE M. P.
Published: April 2008

The spatial distribution of a woodland lizard community was studied in April and July 1980, and January 1981. This study showed that various species of reptiles were microhabitat‐substrate‐specific, hence confirming earlier work on reptiles. Microhabitat niche overlap values and niche diversity were generally low, and a discussion on factors that determine ecological structure and the role of spatial organization in reptile community ecology is given.

La distribution spatiale d'une communauté forestière de lézards fut étudiée en avril et juillet 1980 et en janvier 1981. Cette étude montre que les différentes espèces de reptiles sont spécifiques à des micro‐habitats, ce qui confirme certains travaux antérieurs. Les niches du micro‐habitat se superposent et leur diversité est généralement faible; on discute les facteurs qui déterminent la structure écologique et le rôle de l'organisation spatiale de cette population de reptiles.
Raptors and land‐use systems in southern Africa
Authors: BRANDL ROLAND , UTSCHICK HANS , SCHMIDTKE KLAUS
Published: April 2008

Data about the relative densities of raptors are analysed in comparison to landscape patterns in southern Africa. The impact of man on the environment reduces the diversity of raptor communities. Different raptor groups are influenced differently by man, with habitat destruction as the outstanding negative factor, especially on eagles. Black‐shouldered kite (Elanus caeruleus) and black kite (Milvus migrans) are enhanced by human activities, the former by habitat, the latter by diet. A comparison of data from the literature indicates a decline of raptors (black‐shouldered kite excluded) during the last 30 years in Transvaal and Orange Free State.

Des données concernant les densités relatives de certains rapaces sont analysés en fonction des types d'habitats en Afrique australe. L'impact de l'homme sur l'environment réduit la diversité des communautés de rapaces. Des groupes différents de rapaces sont influencés différemment par I'homme, la destruction de l'habitat étant le facteur négatif majeur, spécialement chez les aigles. L'élanion blanc (Elanus caeruleus) et le milan noir (Milvus migrans) sont favorisés par les activités humaines, le premier par l'habitat, le second par la nourriture. Une comparaison des données de la littérature indique un déclin des rapaces (excepté l'éelanion blanc) durant les 30 dernières années au Transvaal et dans l'Etat Libre d'Orange.
Carcass composition of spur‐winged geese with comments on reproduction and moulting
Authors: HALSE S. A. , DOBBS J. C.
Published: April 2008

Spur‐winged geese at Barberspan, an agricultural area in South Africa, had an average carcass composition of 64% water, 22% protein, 6% lipid, 6% minerals and 2% carbohydrate with an energy content of 21.6 kJ g‐1 DW. There were significant changes during the year in protein and lipid levels; they were lowest during the annual flightless wing moult. Protein and lipid levels also declined during breeding but this event had less effect on body reserves than moulting. The relationships between various body measurements and mineral content of the carcass (as an estimate of skeletal weight) were examined.
Shoot growth and morphometric analyses of Serengeti graminoids
Authors: COUGHENOUR M. B. , MCNAUGHTON S. J. , WALLACE L. L.
Published: April 2008

Nine species from the Serengeti National Park, Tanzania, were studied to provide morphometric and growth rate parameters for a simulation model of their growth (Coughenour, McNaughton & Wallace, 1984). Short grasses had a much greater capability than taller species for packing a large number of shoots with a high proportion of lamina on a given crown biomass. Absolute growth rates varied with species height group, shoot type and growth phase. The frequency distribution of growth rates indicated that maximum growth rates were similar but that modal growth rates decreased with height. This may be an important trait allowing short grasses both to endure unfavourable conditions and to effectively exploit transient showers and resultant water availability. The ability of smaller‐statured specie's to concentrate a high number of shoots with a large proportion of blade on a given crown area is an effective mechanism for increasing productivity early in the growing season. Taller grasses could achieve the same production rates as short grasses only with greater individual growth rates of fewer shoots. These patterns may help to explain gradients of graminoid stature along rainfall and growing season gradients.
Age structure of elephants in Tsavo National Park, Kenya
Authors: OTTICHILO W. K.
Published: April 2008

Following the recent drastic decline in elephant numbers from nearly 35,000 in 1974 to about 14,000 in 1980 in Tsavo National Park, Kenya, the age structures of selected samples of the remaining elephant population were determined in 1980 using the photogrammetric technique. The results show that the present elephant population consists mostly of juveniles and sub‐adults whose age range is between 1 and 15 years. There is a marked scarcity of adults over 15 years. There have been considerable changes in the age structure among the Tsavo elephants over the last 14 years. This paper analyses the factors that have been responsible for these changes.

Suite au récent et drastique déclin du nombre d'éléphants de presque 35,000 en 1974 à environ 14,000 en 1980 au Parc National de Tsavo (Kenya), les structures d'âge d'échantillons sélectionnés de la population restante furent déterminées en 1980 par la technique photogrammétrique. Les résultats montrent que la population actuelle d'éléphants consiste principalement en juvéniles et subadultes dont les âges varient de l à 15 ans. II y a une raréfaction marqée des adultes de plus de 15 ans. II s'est produit de considérables changements dans la structure d'âge durant les 14 dernières années parmi les éléphants du Tsavo. Cet article analyse les facteurs responsables de ces changements.
Breeding seasonality of the African fish eagle in Queen Elizabeth Park, Uganda
Authors: SUMBA S. J. A.
Published: April 2008

The African fish eagle Haliaeetus vocifer (Daudin) in Queen Elizabeth National Park, Uganda, breeds all‐year‐round. Only changes in temperature and water level are significantly but negatively correlated with this breeding seasonality. Social stimulation is not important in the breeding biology of the birds. In this area, the fish eagle exhibits an annual breeding cycle.

L'aigle pêcheur africain (Haliaeetus vocifer (Daudin)) au Queen Elizabeth National Park (°) se reproduit tout au long de l'année. Seuls des changements de température et de niveau d'eau sont en correlation significative mais négative avec cette époque de reproduction. La stimulation sociale n'est pas importante dans la biologie de reproduction chez les oiseaux. Dans cette région, l'aigle pêcheur présente un cycle annuel de reproduction.
Body condition of male Thomson's and Grant's gazelles in relation to season and resource use
Authors: STELFOX J. BRAD , HUDSON R. J.
Published: April 2008

Body condition of male gazelles inhabiting the Athi‐Kapiti Plains, Kenya, fluctuated seasonally. Preferences for upper topographic levels by Thomson's gazelle and for depressions by Grant's gazelle exposed these species to dissimilar biophysical resources and accounted for asynchronous trends in body condition. Thomson's gazelle benefited from early grass growth which occurred along hilltops immediately following the rainy season. Although responding more slowly, body condition of Grant's gazelle was maintained longer into the dry season because of greater use of dicotyledons and the persistence of soil moisture in lower areas.

La condition physiologique des mâles de gazelles dans les plaines de Athi‐Kapiti (Kenya) fluctue avec les saisons. La préférence pour des niveaux topographiques élevés chez la gazelle de Thomson et pour les dépressions chez la gazelle de Grant expose ces espéces à des ressources biophysiques différentes et explique les tendances asynchrones de leur condition physiologique. La gazelle de Thomson profite de la croissance de l'herbe précoce sur les crêtes juste après la saison des pluies. Bien qu'elle réagisse plus lentement, la condition physiologique de la gazelle de Grant se maintient plus longuement en saison sèche à cause de l'utilisation plus complète de dicotylédones et de la persistance d'un sol humide dans les zones basses.
Disturbance effects on elephant feeding: evidence for compression in Luangwa Valley, Zambia
Authors: LEWIS D. M.
Published: April 2008

Dry season patterns of elephant spatial distributions and feeding habits along the eastern boundary of South Luangwa National Park, Zambia were compared over a 3‐year period when levels of human disturbances varied. When disturbances were reduced east of the Park boundary, elephants increased their daytime hours outside the Park. Feeding habits also differed east of the Park where vegetation differences promoted greater use of floodplain grasses and greater range of selectivity of woody species. Primary stem production of mopane trees (Colophospermum mopane) in the Park, prior to lowered disturbance levels, was reduced by almost 100% through elephant browsing. Experimental removal of mopane branches suggested that a tree's tolerance to withstand browse damage by elephants is influenced by its history of past browse damage. Differences in feeding preference and range patterns when disturbances were relaxed, suggested a compression of elephant numbers along the eastern boundary of the South Luangwa National Park. This compression has likely been a contributory factor to a decline of woodland habitats in this Park.

On compare les types de distributions spatiales et de comportement alimentaire durant la saison sèche le long de la frontière orientale du South Luangwa National Park en Zambie, sur une période de trois ans au cours desquels les niveaux de perturbations humaines furent variés. Lorsque les perturbations sont réduites à l'est de la limite du parc, les éléphants allongent leur activité diurne en‐dehors de celui‐ci. Leur régime alimentaire diffère également à l'est du parc lorsque les différences de végétation favorisent une utilisation plus large des graminés des plaines inondées et permet une sélection plus large des espèces ligneuses. La production primaire de pousses des arbres mopane (Colophospermum mopane) dans le parc avant la diminution des niveaux de perturbation fut réduite d'environ 100%à cause du paturage des éléphants. L'enlèvement expérimental des branches de mopane suggère que la tolérance de l'arbre vis à vis des dommages causés par ce paturage est influencée par l'historique des dommages passés. Des différences dans les préférences alimentaires et les types de distributions lorsque les perturbations sont atténuées suggèrent une compression des nombres d'éléphants le long de cette frontière. Cette compression a sans doute été un facteur contribuant au déclin des habitats boisés dans le parc.
Daily movement, grazing activity and diet of savanna buffalo, Syncerus caffer brachyceros, in Benoue National Park, Cameroon
Authors: STARK M. A.
Published: April 2008

Observations on daily movement, grazing activity and diet of savanna buffalo (Syncerus caffer brachyceros) were made over a 10‐month period during 1974–1975 in Benoue National Park, Cameroon. Regular, almost rhythmic, movement to feeding areas and watering sources occurred during mornings and afternoons. Mean distances travelled over a 24‐h period were 7.2±2.62 km during the dry season, and 5.6±1.92 km during the wet season. Dry and wet season ranges were calculated as 61 km2 (0.80 buffalo km‐2), and 46 km2 (1.19 buffalo km‐2) respectively, with 32 km2 (54%) overlap area. Buffalo probably grazed more during daylight hours than at night during the dry season. Total times spent grazing and resting (over a 24‐h period) were estimated at 7.9 h and 9.6 h respectively, during the dry season. Daytime grazing and resting periods during the wet season were estimated at 3.1 h and 3.8 h respectively. Night‐time estimates during the wet season were not possible. Sixteen taxa of plants comprised the diet of buffalo in Benoue National Park. Graminoids, particularly Andropogon gayanus, were taken most often during the wet season (86% of the diet), and dry season (74% of the diet). Woody plants, particularly Piliostigma thonningii, provided 14% of the wet season and 26% of the dry season diets.

On a récolté des observations sur les déplacements quotidiens, le broutage et le régime alimentaire du buffle de savane (Syncerus caffer brachyceros) pendant une période de dix mois de 1974 à 1975 au Parc National de Benoue, au Cameroun. Des mouvements réguliers, presque rythmiques, vers les zones de nourrissage et les points d'eau s'observent le matin et l'après‐midi. Sur une période de 24 h., les distances moyennes parcourues sont de 7,2±2,62 km en saison séche et de 5,6±1,92 km en saison des pluies. On a calculé que les territoires fréquentés sont de 61 km2 (0,80 buffle/km2) en saison sèche et de 46 km2 (1,19 buffle/km2) en saison des pluies avec un recouvrement de 32 km2 (54%). Le buffle broute probablement plus pendant la journée que pendant la nuit en saison sèche. Le temps total consacré au broutage et au repos en 24 h. a été estiméà 7,9 h. et 9,6 h. en saison sèche. Ces mêmes estimations sont de 3,1 h. et 3,8 h. en saison des pluies. Il n'a pas été possible de faire des estimations nocturnes es saison des pluies. Le régime alimentaire du buffle au Parc National de Benoue se compose de 16 espèces de plantes. Les graminées et en particulier Andropogon gayanus sont plus souvent broutées tant en saison des pluies (86% du régime) qu'en saison sèche (74%). Les plantes ligneuses, particulièrement Piliostigma thonningii, participent pour 14% du régime alimentaire en saison des pluies et 25% en saison sèche.
Effects of mountain gorilla foraging activities on the productivity of their food plant species
Authors: WATTS D. P.
Published: April 2008

Mountain gorillas subsist principally on foliage from the dense herbaceous understorey that is found throughout most of their habitat in the Virunga Volcanoes region. Their foraging activities cause considerable structural damage to this vegetation. Those plant species that are quantitatively most important in the gorillas' diet respond to this damage by increasing primary productivity. At a sample of spots at which gorillas had fed, these species showed significantly higher growth rates over a 6‐month interval than they did at nearby spots that had not been touched by the gorillas. Stem densities of herbaceous food species at feeding spots increased markedly both in comparison to their original values and to values for the same species at untouched spots. As a result, spots at which gorillas have fed are likely to become very attractive as future feeding spots. It is unlikely that gorillas ‘manage’ their habitat in any specific fashion, largely because they do not have exclusive use of their home ranges. Their activities appear to maintain habitat productivity over the short term, on a time scale relevant to patterns of area revisits by social groups, and may contribute to long term beneficial alterations of regularly used areas, however. Effects of the type reported here may have been an important aspect of the adaptation by gorillas to terrestrial folivory.

RÉSUMEÉ

Les gorilles de montagne s'alimentent principalement de feuillages dans le sous‐bois herbacé dense présent presque partout dans leur habitat de la région des volcans Virunga. Leurs activités alimentaires causent des dommages structurels considérables à cette végétation. Les plantes des espèces qui sont quantitativement les plus importants dans le régime du gorille réagissent à ces dégǎts en augmentant leur productivité primaire. Aux postes échantillons où les gorilles se sont nourris, ces espèces présentent des taux de croissance significantivement supérieurs sur un intervalle de six mois, par rapport aux postes voisins qui n'ont pas été touchés par les gorilles. Les densités de tiges des espèces herbacées appétées aux postes de nourrissage augmentent nettement aussi bien en comparaison avec leurs valeurs antérieures qu'avec celles de ces měmes espèces dans des stations non touchées. En conséquence, les postes où les gorilles se sont nourris ont plus de chance de devenir des futurs postes de nourrissage très attractifs. Il est peu probable que les gorilles ‘gèrent’ leur habitat d'une quelconque façon, surtout parce qu'ils n'ont pas l'utilisation exclusive de leur domaine vital. Leurs activités semblent maintenir à court terme la productivité de leur habitat, sur une échelle de temps comprenant les visites successives de groupes sociaux, et peuvent contribuer à long terme à des altérations bénéfiques pour ces zones réguliérement fréquentées. Des effets du type rapporté ici peuvent avoir été un élément important de l'adaptation des gorilles à la folivorie terrestre.
Morphometrics and field estimation of the size of the Nile crocodile
Authors: HUTTON J. M.
Published: April 2008

A number of measurements were taken of 104 crocodiles at Ngezi, Zimbabwe. These were used to define the relationship between total length and eight other parameters, particularly those that are associated with size estimation during population surveys. The commonly used ratio between hindfoot (HF) spoor and total length is adjusted to 1:14 where HF <150mm, and 1:13.5 where HF > 150 mm. The accuracy of a ratio of 1:7 between head length and total length, used mostly during night counts, is established. Preliminary work suggests that these results are applicable to other populations.

RÉSUMEÉ

Un nombre de mensurations ont été relevées sur 104 crocodiles à Ngezi (Zimbabwe). Celles‐ci ont servi àétablir la relation existant entre la longueur totale et huit autres paramètres, particulièrement ceux qui sont liés a revolution de la taille durant les recensements de population. L'indice habituellement utilisé entre l'empreinte de la patte arrière (HF) et la longueur totale ajustéà 1: 14 quand HF < 150 mm et à 1: 13,5 quand HF < 150 mm. On établit un indice de 1: 7 entre la longueur de la těte et la longueur totale, en usage lors des comptages nocturnes. Un travail préliminaire suggère que ces résultats sont aussi applicables a d'autres populations.
Some aspects of grasshopper feeding ecology in semi‐arid Acacia woodland
Authors: OKELO R. O.
Published: April 2008

The work was carried out in semi‐arid northern Kenya at Gatab (2°38′N, 36°56′E; altitude 1800m), Luai (2°36′N, 36°57′E; altitude 1350m) and Balesa Kulal (2°32′N, 37°04′E; altitude 650 m). The three sites have two rainfall peaks each year, in April and November. Thirty‐one plant species were individually presented to a total of twenty‐three grasshopper species. It was estimated that grasshoppers in this part of Kenya eat 2·2% of the primary production. The graminivorous and forbivorous grasshopper species ate significantly more grasses and forbs, respectively (P <0·001). Times during the day when feeding activity is high were shown to vary significantly between species (P <0·05) in three grasshopper species: one Pyrgomorphinae (Parasphena kulalensis Kevan) and two Oedipodinae (Aiolopus thalassinus Fieber and Acrotylus patruelis Herrich‐Schaeffer).

RÉSUMEÉ

Ce travail a été effectue dans le Nord semi‐aride du Kenya à Gatab (2†38'N, 36†56'E, alt. 1800 m), Luai (2†36'N, 36†57'E, alt. 1350 m)et Balesa Kulal (2†32'N, 37†04'E, alt. 650 m). Ces trois sites ont deux maxima de chutes de pluies par an, en avril et novembre. On a présenté séparément 31 expèces végétales à un total de 23 espèces de sauterelles. On a estimé que les sauterelles, dans cette partie du Kenya, mangent 2,2% de la production primaire. Les espèces granivores et ‘forbivores’ mangent significativement plus d'herbes et de ‘forbes’, respectivement (P< 0,001). Pendant la journée, le moment où l'activité alimentaire est élevée varie significativement selon les espèces (P<0,05) pour 3 espèces de sauterelles: une Pyrgomorphinae (Parasphena kulalensis Kevari) et deux Oedipodinae (Aiolopus thalassinus Fieber et Acrotylus patruelis Herrich‐Schaeffer).
Effect of forest clearance, season and soil moisture on the activity of the larger soil‐dwelling invertebrates in Dar es Salaam, Tanzania
Authors: MIDDLETON J.
Published: April 2008

Major groups of the larger soil‐dwelling invertebrates were recorded weekly with non‐destructive observations for 2 years. Responses to forest clearance, season and added soil water were assessed. The assemblage of taxa varied only within narrow bounds over the 2 years. Most taxa were more frequent in the field from which forest had been cleared than in a remnant wood. Neither season nor soil moisture was significant in most cases. This component of the decomposition system is not sensitive to the clearing of forest, at least at the gross level of frequency of major taxonomic groups.

RÉSUMEÉ

Les groupes principaux d'invertébrés souterrains furent enregistrés chaque semaine durant 2 ans par des observations non destructrices. Leur réponse à la déforestation, aux saisons et à l'humidité sont établies. L'assemblage des taxons n'ont varié que très légérement au cours de ces 2 ans. La plupart de ces taxons sont plus fréquents aux endroits où la forět a ete coupée que dans les portions résituelles. Ni la saison, ni l'humidité du sol ne jouent de rǒle significatif dans la plupart des cas. Cette composante du système de décomposition n'est pas sensible à la déforestation, au moins à l'échelle générale des fréquences des groupes taxonomiques principaux.
Nutrients and toxins of plants in Amboseli, Kenya
Authors: ALTMANN S. A. , POST D. G. , KLEIN D. F.
Published: April 2008

Nutrient and toxin analyses were carried out on wild foods that are eaten by the baboon (Papio cynocephalus (L.)) and black‐faced vervet (Cercopithecus aethiops (L.)) and other animals in Amboseli National Park, Kenya. Data are provided on proximate composition (water, ash, fat, protein, fibre, other carbohydrates), fourteen minerals, four vitamins (folic acid, ascorbic acid, riboflavin, β‐carotine) and a toxin (trypsin inhibitor). In total, 864 analyses were carried out on ninety‐one foods from thirty‐seven species of plants.

RÉSUMEÉ

On a réalisé des analyses des nutriments at toxines dans l'alimentation du babouin (Papio cynocephalus (L.)), du cercopitheque grivet (Cercopithecus aethiops (L.)) et d'autres animaux du Parc National d'Amboseli, Kenya. Les données fournies concernent la composition approximative en eau, carbone, graisse, protéine, fibres et autres carbohydrates. Quatorze minéraux, quatre vitamines (acide folique, acide ascorbique, riboflavine, carotène β) et un toxine (inhibitrice de la trypsin). Au total, 864 analyses furent réalisées sur nonante et un échantillons protant sur trente‐sept espèces de plantes.
First steps in the ecology of the Bamingui‐Bangoran National Park, Central African Republic
Authors: SPINAGE C. A.
Published: April 2008

A description is given of the 11,560 km2Bamingui‐Bangoran National Park situated in the mid‐Sudanian phytogeographic domain of the Central African Republic. Attention is drawn to the interest of the ecology of this little‐known zone, which lies between north‐south and east‐west ecotones, of the sahel‐tropical forest and oriental region west Africa, respectively. Preliminary collections of plants and small mammals were made. An analysis of the flora and the large mammals observed suggests a predominantly West African affinity. The sub‐specific endemism shown by the large mammals appears more probably linked to Pleistocene isolation by the Chari‐Logone river system, than to a mega Lake Chad as has been postulated elsewhere.
Home range and movement of the common eland (Taurotragus oryx Pallas 1766) in Kenya
Authors: HILLMAN JESSEC.
Published: April 2008

Data were collected in Kenya on the movements of individually recognizable wild eland over a 30‐month period. Further information on movement was obtained from monthly ground counts of Nairobi National Park, and two aerial censuses of the Park and Athi Kapiti plains. Results indicated that adult male eland had restricted home ranges, but that females and juveniles carried out extensive seasonal movements between open grassland and bushed habitats. The numbers of eland in the Park were found to be related to rainfall over the previous two months in the areas outside the Park. It was concluded that females and juveniles were taking advantage of seasonal food abundance in open grassland areas, where the formation of large groups gives protection to small‐sized juveniles.
Reproductive biology of the East African lungfish (Protopterus aethiopicus) in Mwanza Gulf, Lake Victoria
Authors: MOSILLE OLIVA I. I. W. , MMNOYA J. R.
Published: April 2008

The population of lungfish (Protopterus aethiopicus (Heckel)) was sampled by bottom trawling for 12 months from June 1984 to May 1985. A total of 576 lungfish were investigated. The sex ratio in the population was 1 male : 1 ‐98 females. Average size at maturity was found to be 960cm total length (TL) but the smallest matured male measured 72‐9 cm and the female 840 cm TL. It was not possible to establish spawning times and reproductive activity trends either from the variation in relative condition factor ‘kn’ or from gonadosomatic index (GSI). Whereas male lungfish seem to show no further increase in GSI after gonadal maturity stage III, females exhibit GSI values that vary directly with oocyte maturation and ovarian weights. Fat deposited along the gonads was found to be a better basis for assessing maturation and spawning in lungfish. The potential spawning period was found to be from September to May. Absence of lungfish with spent gonads over the 12‐month period and the presence of different egg sizes in ovaries, suggest that the fish is a multiple spawner. Fecundity was found to range from 705 eggs (in 84‐cm TL fish) to 14,922 eggs (in 130‐cm TL Fish).
Patterns of depletion in a black rhinoceros population in Luangwa Valley, Zambia
Authors: LEADER‐WILLIAMS N.
Published: April 2008

Black rhinos in Luangwa Valley, Zambia have been subjected to heavy illegal hunting since the late 1970s. A study population monitored by individual recognition decreased at an instantaneous rate of ‐ 0.29 yr‐1between 1981 and 1985. Two‐thirds of skulls found throughout Luangwa Valley between 1979 and 1985 were axed, indicating death from poaching. All age‐ and sex‐classes of rhino were equally susceptible to being shot, presumably due to the high market‐price of rhino horn.
Vital statistics of the baobab (Adansonia digitata)
Authors: WILSON R. T.
Published: April 2008

Five populations of baobab trees in Zambia, Sudan, Mali, Kenya and Tanzania were measured to establish distribution of girth size classes. Absolute growth rates from rings or from empirical observations in each area were used to convert size into age classes. Baobab populations appear to be much younger than has generally been believed and only very few trees live to ages in excess of 400 years. Instantaneous mortality rates vary from 1 1 to 3–7% per year in the different areas. A lack of recruitment to the youngest age classes is caused by elephants in some areas but land‐use changes due to increasing human populations and increased domestic animal numbers may also be responsible for low recruitment rates in other areas.
Successional patterns of aquatic macrophytes in Jebba Lake, Nigeria
Authors: OBOT EMMANUEL ASUQUO , MBAGWU IHEANYI GODFREY
Published: April 2008

Macrophyte succession in Jebba Lake, Nigeria, was observed through the first four years after impoundment. Two distinct serai phases, a floating fern phase and a draw‐down flora phase could be recognized.

The floristic composition of the macrophyte vegetation was also investigated to check earlier predictions (Obot & Mbagwu, 1986) on the probable structure of the macrophyte flora. The failure of obligate floating macrophytes such as Pistia, Azolla and Salvinia to establish in the lake as predicted is discussed. However, rooted emergent macrophytes were observed to be more successful than would be expected from the predictions.
Nestling growth in the African fish eagle in Uganda
Authors: SUMBA S. J. A.
Published: April 2008

Nestling African fish eagles Haliaeetus vocifer (Daudin, 1858) in Queen Elizabeth National Park (QEP), Uganda, attained and exceeded the adult body weights of their respective sexes by fledging time. The growth curves conformed with the sigmoid form of most animal species. The overall growth rate, K (g/day), was low, averaging 0.077 ± 0.017 g/day and the time t10–90 required to complete growth from 10 to 90% of the asymptotic weight was c. 42 days. Brood size and hatching order did not significantly influence growth rates but the sex of the young did. The tarsus, femur and humerus reached adult sizes by fledging time but the standard wing did not.
Maximum rate of increase in the African Elephant
Authors: CALEF GEORGE W.
Published: April 2008

The theoretical maximum rate of increase for the African elephant is calculated at 7%. This figure agrees closely with the rate of increase observed at Addo Elephant Park, the highest rate of increase reported for elephants living under natural conditions. An elephant population increasing at the maximum rate soon reaches a stable age distribution in which 48% of the animals are older than 11 years of age, (the age of first reproduction) and 6.7% are calves (less than one year old). Several papers have reported frequencies of calves in natural populations of up to twice this percentage. Calculations are presented to show that such high calf frequencies are both theoretically impossible on a sustained basis, and internally inconsistent with the population data presented in these papers.
Somali grasses: germination trials of Cenchrus ciliaris L., Dactyloctenium scindicum Boiss., and Sorghum amndinaceum (Willd.) Stapf
Authors: BARKER J. R. , ABDI M. D.
Published: April 2008

The seeds of three important Somali rangeland grasses, Cenchrus ciliaris L., Dactyloctenium scindicum Boiss, and Sorghum arundinaceum (Willd.) Stapf, were subjected to various scarification treatments: rubbing with sandpaper, soaking in hot water, and soaking in sulphuric acid. Seed germination for C. ciliaris was greatest in the hot‐water treatment and lowest in the sulphuric‐acid treatment. Both D. scindicum and S. arundinaceum germination was highest with the rubbing treatment and lowest with the sulphuric‐acid and hot‐water treatments, respectively. The scarification treatments had no influence on the mean germination times of the three species except for sulphuric acid, which increased D. scindicum germination time.

RÉSUMEÉ

Les graines de trois importantes graminées des pǎturages de Somalie, Cenchrus ciliaris, Dactyloctenium scindicum and Sorghum arundinaceum, ont fait l'objet de divers traitements de scarification: polissage au papier de sable, trempage dans l'eau chaude et dans l'acide sulfurique. La germination de C. ciliuris est la plus importante après traitement à l'eau chaude et la plus faible après traitement à l'acide sulfurique. La germination de D. scindicum et de S. Arundinaceum est la plus haute après traitement de polissage et la plus basse après traitement à l'acide sulfurique et l'eau chaude respectivement. Les traitements de scarification n'eurent aucune influence sur les durées moyennes de germination des 3 espèces sauf que l'acide sulfurique a augmenté la durée de germination de D.scindicum.
Daily activity patterns in captive elephant shrews (Macroscelididae)
Authors: WOODALL P. F. , WOODALL L. B. , BODERO D. A. V.
Published: April 2008

The activity patterns of six species of captive elephant shrews {Elephantulus (four species), Macroscelides and Petrodromus) were monitored electronically for periods of 48 h. Individual animals showed some significant differences in activity from one day to the next but generally followed the same pattern of diel activity. Intraspecific differences were observed in eight Elephantulus edwardii and seven Elephantulus myurus but all had a similar overall pattern of activity apart from a possibly diseased E. edwardii and two E. myurus, which had previously been exposed to a high level of human disturbance, and which showed increased nocturnal activity. All species were active, to varying degrees, both day and night. Interspecific differences in activity exhibited a continuum, with different species showing differing periods of peak activity. Differences in the nocturnal/diurnal ratio may be related to the amount of cover in the habitat and the degree of aridity experienced by each species. Significant seasonal differences in activity were noted in two species where sample sizes were adequate to permit their detection.

On a surveilléélectroniquement le schéma d'activité de six espéces de rats à trompe en captivité par tranche de 48 h. Individuellement, les animaux présentent quelques différences significatives d'un jour à l'autre mais suivent généralement le même schéma d'activité. Des différences intraspécifiques furent observées chez huit Elephantulus edwardii et sept E. myurus mais tous avaient un schéma d'activités globalement similaire, aF l'exception d'un E. edwardii, peut‐être malade, et de deux E. myurus qui avaient ete auparavant soumis à de grands dérangements, et qui montraient un accroissement de l'activité nocturne. Toutes les espèces étaient actives, à des degrés divers, jour et nuit. Les différences interspécifiques étaient permanentes, les espèces présentant des périodes d'activité maximales diffeareés. Les différences du rapport diurne/nocturne peuvent être mises en relation avec le degré de couvertre de l'habitat et le degré d'aridité aux quels est soumise chaque espèce. On a noté des différences d'activité saisonnières significatives chez deux espèces dont la taille de l'echantillon permettait de les détecter.
Food procurement through piracy and scavenging in the African fish eagle in Queen Elizabeth National Park, Uganda
Authors: SUMBA S. J. A.
Published: April 2008

The territorial adult African fish eagle Haliaeetus vocifer (Daudin, 1858) in Queen Elizabeth National Park (QEP) feeds almost exclusively on fish, which it catches live. However, it readily steals from conspecifics and other fish‐eating birds. With a success rate of only 17%–providing only 3% of the fish eaten by the territorial bird–piracy is a less successful method of food procurement than hunting, whose success rate is c. 66%. Even if restricted to depriving only conspecifics (success rate = 23%), piracy is still inferior to hunting. With its low success rate and high risk factor, piracy seems of little survival value to the territorial adult fish eagle. It contributes substantially (28%) to the food supply of the young. However, the fatalities due to injuries sustained during piracy could be of significant importance in the regulation of the population of the species.

L'aigle pêcheur africain adulte Haliaeetus vocifer (Daudin, 1858) du Pare National Queen Elizabeth, se nourrit presque exclusivement de poissons qu'il attrape vivants. Cependant, il ravit volontiers la proie de ses congénères ou d'autres oiseaux piscivores. Avec un taux de réussite de 17%, procurant seulement 3% du poisson que mange cet oiseau territorial, ce piratage est une méthode moins effi‐cace pour se procurer de la nourriture que la pêche dont le taux de réussite est d'environ 66%. Même si Ton ne tient compte que des proies qu'ils volent à des congénères (réussite = 23%), cela reste moins efficace que la pêche. Vu son faible taux de réussite et le risque qu'il engendre, le piratage apparait comme de peu d'intérêt pour la survie de l'aigle pêcheur territorial adulte. II contribue de façon substancielle (28%) à l'apport de nourriture du jeune encore que Tissue fatale des blessures revues lors du piratage puisse compter de façon significative dans la régulation de la population de l'espèce.
The pangolin {Manis temmincki Smuts, 1835) in Zimbabwe
Authors: COULSON IAN
Published: April 2008

A questionnaire distributed to rural areas, and pangolin specimens held by the National Museum in Zimbabwe, provided data on distribution, status, body measurements, diet, reproduction and mortality for Manis temmincki in Zimbabwe.

Grâce à un questionnaire distribué en zone rurale et sur base des spécimens de pangolins que possède le National Museum du Zimbabwe, on a recueilli des données sur la distribution, le statut, les mensurations, le régime alimentaire, la reproduction et la mortalité de Manis temmincki au Zimbabwe.
A simple method for capturing large Nile crocodiles
Authors: KOFRON CHRISTOPHER P.
Published: April 2008

A simple trap and technique were developed for capturing and securing large Nile crocodiles without drugs. The method was successful in capturing 340 crocodiles (total lengths 1 4‐4 1 m) during a 25‐month study in Zimbabwe, including recaptures of both sexes. The trap is a baited mouth snare of cable and rope at shore. A capture team of three persons secured crocodiles as large as 3–7 m, most within 15min of snaring; larger crocodiles required one or two more field assistants. Captures were effected without death or severe injury to crocodiles, and without injury to humans.

Une technique de piégeage simple est développée pour capturer de grands crocodiles du Nil sans anesthésiant. Cette méthode a permis de capturer 340 crocodiles d'une longueur allant de 1–40 à 410 m, y compris des recaptures d'individus des deux sexes, pendant une étude de 25 mois au Zimbabwe. Le piège est un collet fait de cable et de corde, disposé sur la berge et appâté. Pour la capture, une équipe de trois personnes a manipulé desvcrocodiles d'une longueur de 3–70 m, la plupart en l'espace de 15 min après capture. Les crocodiles plus grands nécessitent un ou deux assistants de plus. Ces captures furent réalisées sans entraîner la mort ni causer de graves blessures aux crocodiles et sans blessures aux hommes.
The distribution and abundance of Cubiterrnes sankuvensis (Wassmann) (Isoptera; Termitidae) within a Miombo woodland site in Zimbabwe
Authors: DANGERFIELD J.M.
Published: April 2008

The distribution of apogeal mounds of the humus feeding termite Cubitermes sankurensis (Wassmann) was studied in relation to small‐scale variation in vegetation pattern on three permanent transects within a 5 ha stand of miombo woodland. The composition of vegetation did not have a significant effect on the abundance of C. sankurensis. There was an effect of habitat structure on mound distribution with increased aggregation in areas of open canopy. Factors such as colonization potential and the history of termite activity may be more important in determining the distribution of mounds than the heterogeneity of the vegetation.

La distribution des termitieres épigées du termite mangeur d'humus Cubitermes sankurensis (Wassmann) a étéétudiée en rélation avec les variations à petite échelle du type de végétation dans 3 transects permanents d'une station de 5 ha dans une forêt de type Miombo. La composition de la végétation n'a pas d'effet significatif sur I'abondance de C. sankurensis. La structure de I'habitat a un effet sur la distribution des termitières, plus abondantes la où la canopée est éclaircir.

Des facteurs tels que le potentiel de colonisation et l'historique de l'activité des termites peuvent être plus importants pour dkterminer la distribution des termitières que I'hétérogénéité de la végétation.
Giraffe feeding on Acacia flowers: predation or pollination?
Authors: DUTOIT J.T.
Published: April 2008

Consumption of flowers by the following four browsing ruminant species was monitored for two years in a southern African savanna: giraffe (Giraffa camelopardalis Linnaeus), kudu (Tragelaphus strepsiceros Pallas), impala (Aepyceros melampus Lichtenstein) and steenbok (Ruphicerus campestris Thunberg). Flowers of Acacia nigrescens Oliver are an important food resource to giraffe in the late dry season. This is not necessarily deleterious to the reproductive potential of the plant however, as most or all African Acacia species bear high proportions of sterile flowers. Factors such as inflorescence structure and colour, pollen morphology and thorn structure suggest that one group of African Acacias could be pollinated by ungulates. Timing of flowering in A. nigrescens, and a close association between A. nigrescens and giraffe, indicate that giraffe could well be a pollen vector for this species.

La consommation de fleurs par quatre espèces de ruminants brouteurs de feuilles, a été surveillée pendant deux ans dans une savane du sud de 1'Afrique: la girafe (Giraffa camelopardalis Linnaeus), l'impala (Aepyceros melampus Lichtenstein), le koudou (Tragelaphus strepsiceros Pallas) et le steenbok (Raphicerus campestris Thunberg). Les fleurs de l'Acacia nigrescens Oliver constituent une ressource alimentaire pour la girafe en fin de saison sèche. Ceci ne porte pas nécessairement à conséquence sur le potentiel reproducteur de la plante dans la mesure oú la plupart, voire toutes les espéces d'Acacias africains portent une grande proportion de fleurs stériles. Des facteurs tels que la structure de l'inflorescence, la couleur, la morphologie du pollen et la forme des épines, laissent penser qu'un groupe d'acacias africains pourrait être pollinisé par les ongulés. En calculant la durée de la floraison de l'Acacia nigrescens et une étroite association entre A. nigrescens et la girafe, on déduit que la girafe pourrait bien être un des transporteurs de pollen pour cette espice.
The diet of the spotted hyaenas Crocuta crocuta in Kruger National Park
Authors: HENSCHEL J. R. , SKINNER J. D.
Published: April 2008

In a study of spotted hyaenas Crocuta crocuta in the Kruger National Park, five techniques of diet determination were examined to validate comparison between different studies. Hyaenas frequently scavenged carcasses of large ungulates, particularly buffalo. However, more than half of the mass consumed was from their own kills, primarily of medium‐sized ungulates, impala, kudu and warthog, which became vulnerable due to drought conditions. Animal remains in hyaena scats tended to over‐represent large scavenged species and small prey species, but could be used to indicate that hyaena diet throughout the Transvaal Lowveld depended on the availability of various species, and that buffalo and impala were generally most important. Adult hyaenas consumed about 3–8 kg d‐1, but females appeared to have a better net energy economy than males.

Lors d'une étude sur la hyène tachetée Crocuta crocuta au Parc National Kruger, on a comparé cinq techniques de détermination du régime, pour rendre valable la comparaison de différentes études. Les hyènes mangent fréquemment les carcasses de grands ongulés, spéialement de buffles. Néanmoins, plus de la moitié de la nourriture consommée était composée de proies qu'elles avaient tuées elles‐mêmes, principalement des ongulés de taille moyenne, impalas, koudous et phacochères, rendus vulnérables à cause des conditions de sécheresse. Les restes d'animaux dans les excréments d'hyènes ont tendance à sur‐représenter les charognes des grandes espèces et les petites espèces‐proies mais peuvent servir à montrer que le régime des hyènes dam le veld du Transvaal dépend de la disponibilité en différentes espèces et que le buffle et l'impala y sont généralement très importants. Les hyénes adultes consomment environ 3.8 kg j‐1 mals on remarque que les femelles ont une économie d'éergie nette meilleure que les màles.