bluuebunny/crossref_metadata_2025_split huggingface dataset:
Densités, biomasses et structures des populations d’Ongulés sauvages au Parc de l'Akagera (Rwanda)
Authors: Monfort Alain 
Published: November 2022

Population ecology of wild ungulates has been studied during two consecutive years (September 1968 -August 1970) in the Akagera National Park, Rwanda.
Counts have been made four times a month on six line-transects using a technique similar to that of Lamprey (1963-64).
Each of the 13 more common species has it own ecological preferences, and no inter-specific competition occurs (Table I).
Average densities and standing crop biomasses are given for each of the major habitats of the area (Tables II, III, IV). The densities of sedentary species are remarkably stable from year to year.
Average standing crop biomasses (fresh weight) range from 2705 Kg/Km2 in the Mutara grasslands to 28.286 Kg/Km2 in the tree savanas of the plains. Seasonal fluctuations are due to the seasonal breeding of some species and seasonal migrations of others.
Data are given on the sex-ratio and age-ratio of the major species. Their social structure is described. Habitat is shown to influence social structure in the Topi and the Impala. Both species have different patterns of population dispersion and social grouping in different vegetation types. Among impalas, and apparently also among topis, the percentage of young of the year and juvenile individuals is smaller in areas of high population density.
Biomasse végétale et production primaire nette
Authors: Bille Jean-Claude , Poupon H. 
Published: November 2022

The standing crop biomass, both above and below the ground, has been estimated for the 3 major grassland vegetation types which cover about 65 % of the study area defined in the previous paper and for the 3 most common tree species as well. The net primary production of the above-ground herbaceous vegetation has been measured in the same vegetation types, using the method of Wiegert and Evans as modified by Lomnicki et al. (4968). The root biomass estimated at the peak of the growth period ranges from 4.4 to 2.5 tons/ha, and the above-ground biomass from 0.7 to 3.5 tons/ha, depending upon vegetation type.
The standing crop biomass of trees and shrubs averages 3.5 tons/ha.
The net above-ground herbaceous production ranges from 0.8 to 4.2 tons/ha, 2 to 3 % of which is represented by seeds. This production is strongly influenced by rainfall.
Litter production by tress and shrubs averages 87 Kg/ha.
All biomass and production figures are given in dry weight.
Le gîte du Castor du Rhône (Castor fiber). Description et comportement constructeur
Authors: Richard P. B. 
Published: November 2022

The Eurasian Beaver (Castor fiber) has different types of shelter in France. The burrow generally comprises a short tunnel which rises from beneath the surface of the water, and leads to an hemispheric dwelling place which is situated a few centimetres underneath the level of the water. The burrow is devoid of all material, apart from a mattress of wood, shreaded by the Beavers. The roof is often pierced by an air hole for ventilation. The burrow may vary in relation to the texture of the bank, the variations of the water level, the time period during which the burrow is used, etc. Therefore one can envisage a several levelled dwelling and a burrow with long tunnels ; others are repaired by a visible mass of logs which gradually resemble the hut.
The hut is not dug inside the bank but is built above the bank. Contrary to former opinion, in France the Beaver constructs huts closely resembling those of the Canadian species ; that is to say, a dome of wood and mud, the structure of which is subject to incessant change depending on the number of animals and outside conditions (i. e. mainly, variations of water level and weather) .
The hut can attain great heights while at the same time concealing many independent dwellings. Its origin can possibly stem from a tunnel in the hank or from the bottom of the pond.
The Winter Store. This consists of a pile of willow and poplar branches immersed in close proximity to each other, which are accessible to the Beavers even in times of frost. This supply of the bark of Salicaceae enables these rodents to survive cold periods.
The Screen stretches from the hut towards the water and hides the to-and-fro movements of the dwellers.
Beavers can adapt themselves to unusual conditions. Thus they can construct huts of reed like those of the muskrat : they can live in caves or in the flooded basements of mills ; or indeed in outside shelters for a part of the year.
Building Behaviour. The neural structures of the Beaver do not differ from those of other Bodents apart from the thickness of its brain cortex. However its building behaviour is unique among mammals. It enables the animal to transform its environment to suit its needs.
The paper describes the different stages of hut building, from tunnels dug in the bank or from the bottom of a pond.
Ecologie de migrateurs tropicaux dans une zone préforestière de Côte-d’Ivoire
Authors: Thiollay Jean-Marc 
Published: November 2022

Rollers (Coraciadidae) and Bee eaters (Meropidae) have been studied during three years in a guinean savanna — with galleries and patches of dense forest — in the Ivory Coast. Annual cen- suses of the breeding populations of savanna Rollers have been made by dilferent methods. For the two species a mean density of 1 individual per 4 or 5 hectares has been recorded with a production of young of 22 to 26 %, mainly in May.
Three pairs of related species (Merops gularis and M. albi-collis ; Eurystomus gularis and E. glaucurus ; Coracias cyano-gaster and C. naevius) are compared from an ecological and physiological stand-point. The first-mentioned species of each pair is sedentary, the second migratory. Two of the three sedentary species are forest birds, while all the migrants are savanna birds, with the exception of M. albicollis which also lives in cleared and cultivated forest. Competition is avoided between the two populations through the occupancy of separate ecological niches.
Congeneric species live in dilferent biotopes (or at least vegetation layers). Sedentaries hunt more easily in and around dense vegetation (adaptation to the conditions prevailing during the wet season), while the migrants prefer the most open spaces. The diet of the resident birds is more varied, the migratory species being more specialised in their feeding on swarms of winged ants and termites. Migratory species are much better adapted to the exploitation of this seasonal production or to the appearance of newly accessible prey (ground insects on recently burnt patches of savanna), being able to move rapidly from one place to another and to concentrate locally in large numbers.
Dates of arrivals and departures are compared with the calendar of rains and it is suggested that the timing of the migratory movements in the northern part of the breeding area of these birds is more under the dépendance of the seasons than influenced by local conditions. But it is possible that the rainy season in the Ivory Coast would be too wet to allow a good survival for the populations of these species ; this could also explain the disappearance of our breeding Eurystomus glaucurus from June to September.
Merops albicollis, a typical intra-african migrant, shows a premigratory fattening of about 7 %. This occurs at the end of the prenuptial moult and coincides with the beginning of the increase in the size of the gonads.
La fonction d’apparence chez les Tettigonioidea
Authors: Leroy Yveline 
Published: November 2022

Five different morphological types can be distinguished among Tettigonioidea (Orthoptera) : the «standard» type, the «vertical flat», the «horizontal flat», the «elongated» and the «spherical». The last four help to conceal the insect within its environment. These morphological types are defined biometrically.
The resemblance to the surrounding vegetation is enhanced not only by a variety of colours, patterns and microstructures of the integument, but also by special behaviour patterns and coaptations (Cuénot, 1926). This combination of morphological and behavioural features undoubtedly plays an important role in predator-prey relationships. The total physical characteristics of the prey is less important in terms of adaptation than is its manifest appearance.
Mammalian socialization and the problem of imprinting
Authors: Allyn Georges 
Published: November 2022

The ecology and behaviour of the Oribi Ourebia ourebi have been studied during two consecutive years in the Akagera National Park, Rwanda.
Density estimations have been made regularly along line transects and average values are given for each of the major habitats of the area. Oribis are mostly found on dry savanas in hilly country. They avoid epen plains and more humid valleys. They are not dependent upon permanent water, but are often found near salt licks. Bush fires do not influence their distribution.
Oribis are territorial animals. They are most often met in pairs or family groups. Depending upon population density territories are either scattered or clumped together.
Territorial marking plays an important role in the social behaviour of the species. Scent marking is achieved through the secretion cf interdigital and antorbital glands, as well as through faeces and urine.
The functions of scent marking are discussed. Odours familiar to territorial owners probably give them self-confidence, help maintain the pair-and family-bonds and inform each pair member upon the reproductive status of its partner.
Visual signals mainly have an advertising function.
The sexual display is described. Aggressive postures are seldom seen during the male display, and behaviour sequences which precede copulation are highly ritualized : nose-forward posture, licking of the vulva, nuzzling of the inguinal region, Laufschlag. During mounting, the female adopts a head-low posture. Flehmen was never observed.
Agonistic behaviour can occur between adult males, between adult females, as well as between members of different sexes. As in many other Ungulates advertising display involves proud posture, urination, defecation and scent-marking activities. The threatening animal approaches its antagonist with the head held horizontally and the muzzle pointed towards its rival. Submissive behaviour consists in head-lowering postures. Horn presentation was never observed during fights between males.
Écotopes des arbres et gradients écologiques verticaux en forêt gabonaise
Authors: Oldeman Roelof Arent Albert 
Published: November 2022

The ecotope has been defined by Whittaker et al. (1973) as the «full range of adaptations to external factors of both niche and habitat». This term is the only one among those used by animal ecologists which can be applied to plants without extensive redefinition.
An example is then given, based on the analysis of a plot of an evergreen rain-forest in French Guiana. The study of the growth patterns of trees (architectural models), together with that of the forest structure, during successive developmental and successional stages, makes possible a better understanding of the dynamics of tropical sylvigenesis. In an evergreen rain-forest environment, the climate itself does not exert a limiting influence upon forest vegetation. On the contrary, the growth of individual trees, as well as forest succession, are strongly influenced by the micro-climatic feedback effects of developing vegetation. The stratification of a mature rain-forest is both the cause and the result of this biological regulation, which acts through the modulation of the vertical gradients of light and humidity and manifests itself via «inversion levels».
From the beginning of the regeneration cycle (a tree-fall for instance) to its end (a stratified forest with a small net production), numerous transient eco topes can be distinguished. The plant types proposed at the Kandy Symposium (biological nomads, scar species, sedentary species) appear to play the same role in this biologically determined microclimate as Raunkiaer’s biological types in temperate macroclimates : they represent different ways of reacting to the environment by different strategies of energy and nutrient transfer.
La nidification des oiseaux en forêt gabonaise : Architecture, situation des nids et prédation
Authors: Brosset André 
Published: November 2022

During a five year period data were collected on the location and the architecture of the nests of 110 species of rain forest birds in North East Gabon. 550 nests were observed, out of which 337 were followed until the departure of the fledglings or the disappearence of the eggs or nestlings.
Many forest species make cryptic nests, some of which are built within bunches of dead leaves (Bleda sp.), others are disguised with dead plant material (Nectarinia sp. ; Malimbus sp.) or with caterpillar’s droppings and silk threads (Sylvietta denti). Warblers of genus Camaroptera conceal their nests between leaves which have been sawn together. The Bearded Greenbul Criniger barbatus incorporates into the rim of its nest the epiphytic fern Microgramma owariensis whose foliage remains green during the incubation of the eggs and the rearing of the young. Nicator chloris makes a loose nest «glued » on its support by rotten twigs ; the mycelium which develops in a few days securely binds the nest and its support.
The location of many nests has apparently been selected in order to keep them from being located on the arboreal or terrestrial paths of predators : small trees isolated in the undergrowth, tips of horizontal twigs projecting above open spaces, tips of hanging lianas, branches overhanging water, intervals between the buttresses of the tree trunks, etc. Contrary to what frequently happens in temperate forests no attempt is generally made to conceal nests under foliage. More than two thirds of the nests discovered by the author were subsequently destroyed by predators or accidents. Whereas the concealment of the nest itself does not appear to be a very effective anti-predator device, the location of the nest is much more efficient : 70 % of nests located in the small trees of the undergrowth were destroyed as against 50 % of those built at the tip of projecting twigs, and 35 % of those overhanging water. Twenty per cent only of the nests located between buttresses were destroyed.
A comparison is made with Maria Koepke’s observations in Eastern Peru. Unrelated species with similar ecological requirements usually have similar nesting habits. Some striking cases of convergence are mentioned between Galbulidae and Meropidae, Alcedinidae and Bucconidae, Tyrannidae and Nectariniidae, Icteridae and Ploceidae.
Exemple de prédation naturelle sur une population nicheuse de Quelea Q. Quelea (L.) au Mali
Authors: Thiollay Jean-Marc 
Published: November 2022

The predation pressure upon nine breeding colonies of Red-billed Quelea (Quelea q. quelea) has been estimated in September 1973 in Eastern Mali, Western Africa.
Large numbers of predatory birds (Kites, Hawks, Ruzzards, Eagles, Falcons, Storks, Herons, Ibises, Hornbills, Crows, etc.) were found to feed upon young queleas : up to 763 predators in a colony of 28,000 nests. Details are given on feeding techniques, food preferences and average daily consumption of the most important predators.
In this particular case, 32 % of the nests were destroyed between laying and hatching times. Furthermore 25 % of the nestlings appear to have been subsequently destroyed by predators. On the whole, each adult breeding pair did not produce more than 1,7 fledglings. The causes of this unusually high mortality rate are discussed.
Ecologie de Cercopithecus ascanius schmidti dans les environs de Bangui
Authors: Galat-Luong Anh 
Published: November 2022

Preliminary observations on the social structure and ecology of a troop of Red-tail monkeys (Cercopithecus ascanius schmidti) were made between 1970 and 1972 around Bangui, Central African Republic.
The age-graded male troop studied ranged from 17 to 23 troop members, including 4 adult males, one of which (the GM male) was much bigger than the others, one subadult male (PN), six adult females, six juveniles and six infants. The troop very often splits into sub-groups by day as well as by night : «family parties » (Haddow, 1952) made up of one adult male and one adult female accompanied by its young of the year, female travelling parties, juvenile play groups. The association between the «master male » GM and the subadult male PN lasted for a whole year ; both of them were usually found staying outside the rest of the troop.
The troop’s home range averaged 15 hectares, five of which representing the core area. Two different sleeping trees were used during the observation period. Some details are given on the diet, the daily schedule of activity, and their seasonal variations.
Mating occured during the day and outside the group. Seasonality of breeding is the rule ; six young infants were observed in September.
Coexistence de Vipera aspis et de Vipera berus en Loire-Atlantique : un problème de compétition interspécifique
Authors: Saint Girons H. 
Published: November 2022

L’étude en Loire-Atlantique de la zone de contact entre Vipera aspis et V. berus montre clairement que les deux espèces s’excluent mutuellement. Non seulement la zone de coexistence est très étroite (1 à 2 kilomètres), mais en réalité même cette bande est constituée par des petites populations juxtaposées et non mélangées. Bien que possible, l’hybridation demeure un phénomène exceptionnel et, en pratique, les deux espèces sont sexuellement isolées.
En l’absence d’intolérance active, nous avons cherché à connaître la nature de cette compétition interspécifique, en étudiant l’écologie et le cycle annuel des deux espèces dans les mêmes localités et les mêmes biotopes. Bon nombre de différences ont été mises en évidence, les unes d’ordre spécifique (le cycle sper-matogénétique, la nature des proies acceptées, etc.), d’autres représentant la simple conséquence des conditions climatiques locales (par exemple, la reproduction triennale de Vipera aspis).
Dans la région étudiée, à étés frais, V. aspis souffre d’un net déficit thermique : les femelles ne se reproduisent plus que tous les trois ans en moyenne et la date de la parturition se rapproche dangereusement du début de l’hivernage. Ceci est certainement dû à une thermorégulation écologique moins efficace, peut-être aussi à des exigences thermiques supérieures lors de la digestion et de la gestation.
Vipera berus est très certainement avantagée par un taux de natalité plus élevé et par un régime plus éclectique. Mais, gardant un comportement adapté à la vie dans des régions beaucoup plus froides, elle s’expose davantage à l’action des divers prédateurs. Ce phénomène est aggravé par le cycle spermatogénétique comportant une spermiogenèse vernale qui oblige les mâles à une recherche intense et dangereuse de l’insolation à cette époque.
Le fait que les deux espèces ne puissent cohabiter et s’éliminent mutuellement, bien que leurs exigences écologiques diffèrent par un certain nombre de points, est dû apparemment à ce qu’elles fréquentent les mêmes biotopes et se trouvent ainsi soumises ensemble à une pression de prédation à laquelle elles réagissent différemment. Un léger désavantage suffit alors pour que l’une d’elles se trouve éliminée, sans qu’intervienne de compétition, alimentaire ou autre.
D’après l’ensemble de nos observations, la frontière entre Vipera aspis et V. berus se situe au point où la baisse de fécondité de V. aspis n’est plus compensée par la plus grande vulnérabilité de V. berus aux prédateurs, et inversement.
La colonisation de la mangrove par Cercopithecus aethiops sabaeus au Sénégal
Authors: Galat Gérard , Galat-Luong Anh 
Published: November 2022

Cercopithecus aethiops sabaeus have been known since 1906 to inhabit the mangroves of Southern Senegal, where they are called locally «mangrove monkeys».
An age-graded male troop of 33 individuals has been briefly studied in 1975 around the estuary of the Saloum river ; usually it split into smaller sub-groups or foraging parties during the day and even sometimes during the night. The troop’s home range averaged 138 ha. Territorial contests between adult males of adjacent troops have been observed ; these involved «loud barks», «chest exposure» and «penile display».
The troop studied spent 80 % of its time within the mangrove and only 13 % on the mainland. Sleeping trees can be located in both habitats, but mostly in the mangrove. Though C. a. sabaeus can swim, they prefer to cross mud flats and shallow water channels at low tide, or progress through the Rhizophora stilt-roots or pass from one tree crown to the other.
The time-budget of the troop is given. The monkeys were observed feeding during 8.1 % of their activity time only. In 52 % of the cases they were seen hunting fiddler crabs (Uca tangeri) and 22 % of the cases eating Rhizophora flowers, fruits, shoots and young leaves, as well as the «pith» of young stilt-roots. Two different hunting techniques for crabs are described.
Structure et dynamique d’un peuplement d’Amphibiens en savane protégée du feu (Lamto, Côte-d’Ivoire)
Authors: Barbault R. 
Published: November 2022

The bush-fires which occur yearly in the Lamto savana, during the dry season, do not affect Amphibian populations directly, but rather through their action upon vegetation structure and micro-climate.
The population density and relative abundance of the various species were studied during 1964-1965 in two unburnt 30 X 30 m plots : one which had been protected from fire for two years and another which had remained unburned for five years. Comparisons were made with populations from burned plots and nearby gallery forests.
The obvious differences of population densities and relative species abundance so far described between savanna and forest communities, as well as between «bottom» and «plateau» communities within the savanna, tend to disappear when bush-fires are prevented. However the seasonal cycle of population abundance remains basically the same in both cases.
In unburnt savanna plots the density of Amphibian populations increases rapidly and is already noticeable during the second year. Population density may be increased 2 to 3 fold. This is mostly due to a proliferation of one species (Arthroleptis poecilo-notus), which takes place simultaneously with the reduction in numbers of the toad Bufo regularis.