bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations sur la reproduction et la dynamique des populations de quelques Anoures tropicaux. I. Ptychadena maccarthyensis et Ptychadena oxyrhynchus
Authors: Barbault R. , Trefaut Rodrigues M.
Published: November 2022

The populations of two frogs, Ptychadena maccarthyensis and P. oxyrhynchus, were studied over a four-year period in the Lamto savanna (Ivory Coast), where the climate is characterized by a dry season lasting from December to February, and a rainy season from March to November.

P. oxyrhynchus breeds from February to May, while P. maccarthyensis does not breed before March but can continue to do so until October.

Consideration of size-frequency histograms constructed from sequential samples in the two populations shows that the two species reach sexual maturity 8 to 9 months after metamorphosis, when the females attain a length of 43 mm for P. maccarthyensis and 59 mm for P. oxyrhynchus. There is very little overlap in adult size, either between sexes or species. Average clutch size is 1333 eggs in P. maccarthyensis and 3476 eggs in P. oxyrhynchus. The laying of a second clutch of eggs during the year has not been observed. However there is a strong probability that this does in fact occur, particularly in P. maccarthyensis which has a long breeding season.

Fecundity is high in the two species studied. The mortality rate is high for eggs and young individuals, especially during dry years. Adult mortality is low.
Méthodes de détermination de l’âge chez le chat haret des îles Kerguelen
Authors: Pascal Michel , Castanet Jacques
Published: November 2022

The different methods of age determination used in the study of mammals are compared, using a sample (N = 292) of feral cats (Felis catus L.) from the Kerguelen islands as an example.

“Skeletal growth marks” in bone and cementum have already been used successfully on several species of Mammals. In our case, emphasis has been especially put on the critical use and discussion of these methods of “skeletochronology”.

No direct comparisons with animals of known age being possible, we had to rely on circumstancial evidence to demonstrate the value of the method. Bone tissue (jaw) and dental cementum were both used and compared. A critical study of the histological patterns shown by the tissues allows a functionnal interpretation. Wide zones of fast deposited tissues (warm season deposits) alternate with narrow annuli (narrow “rest lines” here called LAC = lignes d’arrêt de croissance) which are cool season marks.

The results have been cheked against other methods of age determination, such as body weight, dry weight of the eye lens, and tooth succession. A good correlation has been found between the results from these different techniques.

Seven age groups have been found and the best age resolution for adults fall to six months.
Les peuplements de Fourmis et les peuplements d’ Acridiens du Mont Ventoux. II. Les peuplements de Fourmis
Authors: Du Merle Paul , Marro Jean-Pierre , Mazet René
Published: November 2022

The composition of the ant communities and the relative frequency of each species are described, as well as their ecological and altitudinal amplitudes. The richness and/or the composition of the communities differs from one vegetation zone to another. All the communities show a very hierarchical structure. The Shannon eaver index of evenness is roughly equal in all communities. The communities are very varied, but three species are predominant over the mountain : Lasius niger, Tetramorium caespitum and Formica lemani.

Of the environmental features, temperature is the most important, producing a marked altitudinal zonation of species and communities. The effects of aridity are important among certain species, leading to vertical discontinuities in their ranges. The vegetation cover affects species dependant on particular plants ; these species have been considerably affected by reafforestation, especially on the lower parts of the southern slopes, leading to a notable increase in L. niger. At the summit, the main limiting factor is temperature on the northern slope ; and the dessicating effects of the winds on the southern slopes.
Importance, répartition et tendance évolutive des populations de grands herbivores et de l’autruche dans le parc national de Waza, Cameroun
Authors: Esser J. D. , Van Lavieren L. P.
Published: November 2022

Un dénombrement aérien des grands herbivores et des autruches du Parc National de Waza a été effectué en utilisant un échantillonnage stratifié sur transects. On a divisé le parc en cinq «strates» différentes suivant les types de végétation et la densité des animaux. Les estimations d’effectifs de sept espèces sont présentées, ainsi que des cartes montrant la répartition spatiale et la densité des grands mammifères et de l’Autruche. Ces résultats sont comparés avec ceux d’un recensement précédent et avec d’autres estimations d’abondance.

Les effectifs des damalisques, hippotragues et autruches montrent un déclin important. Les reduncas, autrefois très communs dans le parc, sont devenus très rares ; de plus, les cobes onctueux ont complètement disparu de la région, aucun n’ayant été observé pendant le recensement.

Les effectifs des éléphants et des girafes semblent stationnaires ou même en légère croissance. La population de cobes de Buffon, l’herbivore le plus abondant du parc est elle aussi en diminution, moins rapide cependant que celle des damalisques et des hippotragues.

Les causes possibles de cette diminution de la grande faune sauvage du Parc National de Waza sont discutées. L’action directe et indirecte des activités humaines paraît prépondérante.
Une approche synécologique des milieux humides savoyards et de leur avifaune
Authors: Tournier Hubert , Lebreton Philippe
Published: November 2022

Une étude a été conduite de la répartition qualitative de 78 espèces d’oiseaux dans 25 milieux humides de Savoie, déterminés par leur structure végétale. Cette matrice de données a été analysée par la technique des coefficients d’affinité (Jaccard, Czekanovski ) et celle, plus moderne, de l’analyse factorielle des correspondances.

Les milieux jugés à travers leur avifaune s’ordonnent selon un axe paludicole principal, sur lequel se greffent deux axes latéraux d’eau libre, courante et stagnante. Correspondant à la notion de série de végétation et déterminée par elle, se dégage la notion de séquence ornithologique.

Diverses relations ont été établies concernant le nombre d’espèces aviennes en relation avec le nombre de strates végétales, ainsi que la répartition de l’avifaune en espèces migratrices et/ou plus généraux de structure des peuplements aviens en relation carnivores. Le présent travail est donc un apport aux problèmes, plus généraux de structure des peuplements aviens en relation avec leur milieu.
Contamination des eaux de drainage de rizière et de leurs réceptacles (canaux, étangs) par les résidus de produits phytosanitaires en Camargue
Authors: Podlejski Jacques
Published: November 2022

The present study was undertaken to determine the level of contamination of drainage water of an experimental ricefield by two insecticides, γ H.C.H. and Parathion, two herbicides Moli-nate and Propanil and 3,4 D.C.A. a degradation product of Propanil. Changes in the concentraitons of the chemicals and of total discharge of the drain water were recorded, and thus the total amount of each chemical released over the growth season was calculated. The consequences of these discharges on aquatic ecosystems recieving drain water are discussed.
Le concept de niche écologique illustré par le cas de populations congénériques sympatriques du genre Acrocephalus
Authors: Henry Claude
Published: November 2022

The niche overlap between Reed Wablers and Sedge Warblers during the breeding season is discussed.

At that time of the year Reed Warblers are “generalists”, feeding upon more than fifty arthropod taxons. However 80 % of this insectivorous diet is made of 22 species only, 2 to 11 being caught the same day. Within a given prey category, some species are caught by Reed Warblers and not by Sedge Warblers. Most of the prey taken are 1 to 4 mm long (modal value : 3.2 : range 0.5 to 22 mm).

Sedge warblers are also generalist insectivores, 26 taxons being represented in their diet, 6 to 17 being caught the same day. Prey taken are the same as that caught by Reed Warblers, although some prey items are not taken by the latter species. Prey size distribution is bimodal ; the first modal value is 3 mm, the second 9 mm (range : 1-24 mm).

The Morisita index is used to estimate niche overlap between the two species. Total overlap index is 0.93 for taxons, and 0.97 for prey size. The niches of the two warblers cannot therefore be separated on the basis of their respective diets. The two species, however, build their nests in different habitats, the Reed Warbler in Phragmites beds and the Sedge Warbler in Carex beds, close to water. Both also forage outside their nesting habitat, in willow groves, wheat and barley fields.

The high predation pressure exerted upon the nestlings of both species might explain the choice of their nesting sites.
Niche écologique et diversité spécifique des espèces sympatriques dans le genre Cercopithecus
Authors: Gautier-Hion A. , Gautier Jean-Pierre
Published: November 2022

It is difficult to separate the ecological niches of three sympatric species of Cercopithecus living in North-East Gabon on the basis of the niche parameters usually studied by prima-tologists : their habitats are very similar, their activity rhythms are the same and the vegetation layers they frequent overlap broadly.

The three species have a very similar diet at the times of the year when food is readily available. The inter-specific differences in diet only become apparent during the “lean season”. At that critical period of the yearly cycle, the two species (C. nictitans and C. pogonias) whose habitat is the most similar, are also those whose diet is the most different. Food preferences between C. nictitans and C. cephus on one side, C. pogonias and C. cephus on the other side are not so marked, but C. cephus tends to forage in the lowest layers of the forest vegetation and in the areas where foliage density is the highest.

The three sympatric Cercopithecus species appear to feed upon the same kinds of fruits. They differ however in their preferred animal prey.

The three Cercopithecus species concerned also frequently live in “mixed groups” in the same area. Such an inter-specific association does not appear to reduce the niche breadth of the participating species, and no competition was observed. The formation of mixed groups of sympatric forest monkeys might then be considered as an adaptative strategy to optimize the utilization of available forest resources, three closely related but complementary species being more efficient resource-users than a single “generalist” one.
Préférences alimentaires chez Quéléa Quelea quelea (L.)
Authors: Manikowski Stanislaw , Da Camaha-Smeets Michèle
Published: November 2022

Three hypotheses are advanced to explain the damage to crops caused by Quelea quelea :

1) non-availability of wild gramineous seeds, which are usually the normal quelea food ;

2) ready availability and ease of access to crops ;

3) marked preference for crops.

Cage experiments on food choices among some of the most frequently eaten seeds (both cultivated and wild) and the size of these seeds, demonstrate quelea’s preference for seeds of the size of millet. Since seeds of this size are scarce in the quelea habitat, this suggests that quelea would tend to damage crops, even if wild grass seeds were abundant.
On the germination of seeds in the dung balls of the African Elephant in the Virunga National Park
Authors: Brahmachary Ratan Lal
Published: November 2022

At least 1591 out of 2576 seeds germinated in the Elephant dung at Virunga National Park belonged to one species, Capparis tomentosa. Elephants play a significant role in the dispersion of seeds, especially those of Capparis tomentosa and Maerua sp. and various wild Curcubitaceae and Solanaceae. Direct observation showed that 65 out of 112 mouthfuls were non-grass species, even when the elephant was grazing on short grass.
Morphologie, croissance individuelle et dynamique des populations de la Tortue verte (Chelonia mydas L.) au Banc d’Arguin (République Islamique de Mauritanie)
Authors: Le Toquin A. , Galmel E. , Trotignon J.
Published: November 2022

The carapace morphology and growth of the Green turtle (Chelonia mydas L.) has been studied in a large (n = 177) sample of animals collected by the Imragen fishermen on the Banc d’Arguin (Islamic Republic of Mauretania). The frequency of anomalies of the scales decreases with age in this species, possibly due to a differential mortality between normal and abnormal individuals.

The mathematical relation between length and width of the carapace is discussed and the Mauretanian data are compared with those of other areas. There are obvious differences in the shape of the carapace between different breeding populations of green turtles, which quite likely correspond to genetic differences between various breeding populations. The Mauretanian green turtles are quite similar to those breeding on the eastern coast of South-America.

Seven age classes can be recognized on the basis of the carapace length.

A growth curve of the Mauretanian population of Chelonia mydas L., based upon von Bertalanffy equation, is proposed. The rate of growth decreases sharply after the first breeding season. Sexual maturity takes place at 5.5 years of age, but age at first reproduction apparently varies from one population to the other, probably depending upon fishing pressure. The number of «bachelors» (mature individuals not taking part in reproduction) is apparently greater in areas with the smallest fishing pressure.
Recherches sur les écosystèmes des réserves biologiques de la forêt de Fontainebleau. VII. Structure et fonctions des peuplements de houx (Ilex aquifolium L.)
Authors: Clabault G. , Lemée G. , Bichaut N. , Legay B. , Pontailler J.Y.
Published: November 2022

Holly bushes form an important structural unit in some natural reserves of the Fontainebleau forest (60 km S.E. of Paris). Due to the high stem density of the holly, its great basal area and the longevity of its leaves (about two years), the biomass and the global productivity of the mature beech-oak forest are appreciably increased.

This additional production brings about a large immobilisation and important turn-over of nutrients. Holly plays an important role as potassium accumulator and magnesium cycle accelerator.

The leaf litter, falling alternately from holly and trees, is appreciably increased in volume and its mineral and nitrogen contents are enriched. During the first months following leaf drop, decomposition of the holly litter is very rapid.

The actual evolution of holly populations tend to be extended by the peripheral formation of suckers and by seedlings. Under the bushes, deep shade and thick litter accumulation inhibit any regeneration. The progressive substitution of old oaks by beeches is unfavorable to holly. The presence of holly stands could represent a preterminal stage of this forest succession.
Organisation spatio-temporelle des activités individuelles et sociales dans une troupe de Cercopithecus cephus
Authors: Quris R. , Gautier Jean-Pierre , Gautier Jean-Yves , Gautier-Hion Annie
Published: November 2022

A monospecific troop of Cercopithecus cephus was followed for five months using the radio-tracking method. Temporal and spatial distribution of the activities is described.

Two peaks of locomotion are found in the first half of the morning and the second half of the afternoon. Phytophagy follows the same rhythm, while feeding on prey and resting increase at mid-day. Strong daily variations are shown in forest type usage according to the activity performed. The more open and tallest forest is chosen during the night and for fruit gathering, while the densest and lowest one is significantly preferred for resting. Parallel daily variations are found in the forest level usage : resting, insect hunting and social interactions occur at levels lower than locomotion and fruit gathering.

The total time spent feeding does not differ between the age classes, however the time spent feeding on insects decreases with age while phytophagy increases. The young are found at significantly lower levels than the adults. The adult male stays higher than the other troop members, especially when resting.

Inter-individual distances are lowest between females and young, while the adult male has a more peripheral position. Troop cohesion is higher at the end of the day.

Physiological, behavioral and environmental constraints which might influence such activity rythm and differences between age classes are discussed.
Détermination de l’âge par pesée du cristallin chez le Lérot Eliomys Quercinus (L.)
Authors: Baudoin Claude , Abdi Hervé
Published: November 2022

Dans le but d’étudier la composition de populations naturelles de Lérots en Franche-Comté, nous avons utilisé le poids sec de cristallin pour estimer l’âge des animaux.

La croissance pondérale du cristallin est rapide durant les 6 premiers mois de vie chez les 55 Lérots (29 ♂ ♂, 26 ♀ ♀) nés et maintenus en captivité, puis elle est ralentie entre 6 mois et 1 an. Ce ralentissement s’accentue au-delà de 1 an. La croissance est alors très lente sans toutefois s’arrêter.

Sur un échantillon de 24 animaux âgés de 1,5 à 6 mois, nous avons montré que le poids de cristallin dépend linéairement de l’âge. La valeur estimée du poids de cristallin s’exprime par la

formule Y = 27,448 X + 70,801. Les limites supérieure et inférieure de l’estimation sont calculées.

Par la méthode de prédiction inverse (Sokal and Rohlf, 1969), nous avons ensuite calculé l’âge estimé de 41 Lérots (17 ♂ ♂ et 24 ♀ ♀) capturés dans la nature. La comparaison de l’âge calculé par cette méthode à l’âge estimé au moyen d’autres critères montre une bonne concordance entre les données.

L’analyse des résultats a également permis de mettre en évidence un ralentissement de la croissance pondérale du cristallin en cours de l’hibernation chez les Lérots vivant dans la nature en Franche-Comté. Une autre méthode (analyse factorielle des correspondances) est utilisée pour ordonner les individus après leur première hibernation (Baudoin et Abdi, 1981).
Sur les «niches écologiques» de quelques plantes du Languedoc
Authors: Godron Michel
Published: November 2022

The distribution in space, and the propensity to be associated with other plant species, can well be considered as important dimensions of the ecological niche of a plant.

This is demonstrated by the results obtained during a vegetation survey of the «garrigues» around Montpellier.
Capacités prédatrices et budgets d’activité chez l’Aigle pêcheur Haliaeetus vocifer
Authors: Thiollay Jean-Marc
Published: November 2022

Ten pairs of Fish Eagles Haliaeetus vocifer taken among a dense population in Uganda, were followed at the end of the breeding season to compare the time and energy budgets of breeding and non breeding adults.

Fish are usually obtained by diving from a waterside tree. If unsuccessful, the bird searches in flight, an energy-expensive but very rewarding method. The additional food necessary to feed the young is provided mainly by the male through fishing flights. Another source of increase in energy expenditure related to breeding activities is the more active territorial defense by adults with young than without young. The food consumption of the former is higher than that of the latter ; but the difference is smaller than the increase of the energetic cost of breeding (42 % and 64 % for 1 and 2 fledged young). Thus brood size seems to be limited by the ability of the parents to feed their young and maintain a territory of adequate size or quality, even in the optimal conditions studied.

Immature birds suffer heavily from the adults’ territorial behaviour, which forces them to make extensive flights and confines them to marginal food sources. This may explain their high mortality rate (83 % during the first four years).
Les peuplements de poissons de la Camargue
Authors: Crivelli Alain Jean
Published: November 2022

Fish communities in the Camargue wetlands, both temporary and permanent marshes as well as irrigation and drainage canals, were studied from 1977 to 1980. The main part of this work was carried out in wetlands isolated from direct contact with the sea by a dike, the Digue à la mer. Three major types of wetlands and their associated fish species are described in the Camargue : the freshwater (0-5 g/1 C1￣ ), the brackish (5-16 g/1 C1￣ ) , and the very brackish (16-35 g/1 C1￣ ) . A significant relationship (P< 0.01) was found between the species richness and the surface area. The slope of this regression (0.134) is lower than that found for other aquatic systems. Four associations of fish were determined and their meaning is discussed. The biomass of temporary freshwater marshes ranged between 13 to 76 kg/ha and was much lower than those found in the small freshwater canals : 112 to 2 544 kg/ha. Common carp, Cyprinus carpio L., is the dominant species in freshwater wetlands (70 to 85 % of total biomass). A space partitioning between the immature and the adult carp is described. In one waterbody studied south of the Digue à la mer, linked temporarily with the sea, the fish community composition underwent frequent and rapid changes according to the variations of environmental factors. The salinity appeared to be the most important factor affecting diversity and eveness of the fish community in this etang. A canonical analysis was used to determine which of the environmental factors had the greatest impact on the abundance of the different fish genus. Only 46.2 % of the fish species studied reproduce in the Camargue, while 35.9 % migrate to the sea for spawning. The importance of a link with the sea as well as that of a sound water management plan for the Camargue as a whole are pointed out.
Quelques aspects de la socioécologie de la Vigogne Lama vicugna
Authors: Ménard Nelly
Published: November 2022

A population sample of vicunas has been studied during 1979-1980 in the Pampa Galeras National Reserve in Southern Peru. Since 1965 the populations of this species which were previously on the verge to extinction, have increased sharply following effective measures of protection and good pasture conditions favoured by a succession of wet years.

The social structure of the population studied includes groups of bachelor males roaming over extensive ranges, and harems settled on smaller territories and defended by an adult male.

The observations were mainly focused on two family groups :

— the Canllapampa Valley harem, composed of one male, one adult female and her young, one 2-year old female and one yearling female ;

— the Llamaiso Valley group, composed of one male and one adult female with her young.

Since 1974, there has been a severe drought in the Reserve, causing changes in the social organisation and the social structure of the whole population, as well as in the pattern of range use. Therefore, our 1979-1980 observations are compared to those of Franklin, carried out in 1971, during a typical rainy year. Since that time annual censuses have shown that the population has increased regularly until 1978 and that its demographic structure changed, through an increase in the nomber of bachelors. Whereas the size of reproductive territorial groups, as well as the surface area of their territories, decreased during that period, the mean reproduction rate changed from 74 % in 1971, to only 33 % in 1979 due to numerous miscarriages.

Our 1979-1980 observations indicate that the males on Canllapampa became aggressive towards juvenile females during the dry season (from May through November 1979) before expelling them. Moreover the one adult female studied suckled her young until February, whereas weaning occured between September and December in 1971. This indicates a tendency to breed only once every second year.

All the year round, vicunas presently spend an average of 89 % of their time grazing, without any significant seasonal variation. During the dry season vicunas may temporarily leave the male territories and cover great distances to graze on other pastures.

All these changes which have occured after several dry years seem to indicate that the vicuna population is presently facing very harsh living conditions on very poor pastures. Indeed, the population began to decrease in numbers during 1979.
Rafflesia. La plus grande fleur du monde menacée d’extinction
Authors: Meijer Willem
Published: November 2022

Attention is called to the recent destruction of a number of rainforest localities where Rafflesia arnoldii and other species of Rafflesiaceae were formerly observed.

The nature reserves of South-East Asia where Rafflesiaceae are still present are listed. A plea is made for a more efficient conservation policy of this unique plant family.
Premières données sur l’écologie des populations naturelles de souris, Mus spretus Lataste et Mus musculus domesticus Rutty dans le Midi de la France
Authors: Orsini Ph. , Cassaing Jacques , Duplantier Jean-Marc , Croset Henri
Published: November 2022

Après avoir rappelé les critères d’identification des deux Souris du Midi de la France, Mus spretus et Mus musculus domesticus, les auteurs précisent la répartition biogéographique et écologique des deux espèces. Leurs observations montrent que Mus musculus domesticus est limitée vers les biotopes arides (garrigues à Chêne kermès), par ses exigences hydriques. A l’inverse, la limite de Mus spretus vers les biotopes humides ne peut être expliquée par des facteurs mésologiques. Des expériences préliminaires, au laboratoire et en enclos extérieurs, semblent indiquer une limitation de la reproduction de Mus spretus par Mus musculus domesticus dès que les conditions mésologiques sont favorables à cette dernière.
Rythmes d’activité et régimes alimentaires de Proechimys cuvieri et d’ Oryzomys capito velutinus (Rodentia) en forêt guyanaise
Authors: Guillotin Michel
Published: November 2022

Proechimys cuvieri and Oryzomys capito velutinus have been studied in two forests of French Guyana, on the Arataye River and at Saint-Elie. Whereas both areas are covered by mature rain forest, the Saint-Elie site includes a 25 ha parcel of 4 year old second growth.

The daily movements of the animals were followed by radio-tracking, and the use of a fluorescent powder, sprayed on a number of individual rodents, and whose traces on the ground and/or vegetation were detected with a UV lamp. Various methods were also used to study the diet of the two species : analysis of stomach contents, identification of partially consumed food items and of fruits found in nests or resting places (only Proechimys cuvieri hoards fruits in food caches), as well as «cafeteria » experiments in captive conditions.

Both species are strictly nocturnal in their activities, with two activity peaks during the course of the night. In P. cuvieri , males cover twice as much distance per night as females do. In both species, males have larger home ranges than females.

Proechimys and Oryzomys are mostly frugivorous, the diet varying with the sex of the animal, the season and the forest type. Proechimys cuvieri eats more insects during the dry season, when fruit production is low, than during the rains. Males are more frugivorous than females, and both sexes are almost exclusively frugivorous in young second growth. There is a difference in size of the fruits consumed by the two sympatric species, which parallels their difference in body size.

The trophic impact of Proechimys cuvieri on the available fruit resource is low, but the animal quite likely plays an important role in seed dispersal.
La relation fréquence-abondance. Aspects théoriques ; application à un peuplement d'oiseaux
Authors: Frelin Christian
Published: November 2022

The frequency of a species (proportion of samples in which the species is recorded) is a non linear function of its abundance, which is modified by the pattern of distribution of the individuals and by the surface of the area sampled. These parameters determine mine the probability of presence of a species. The probability of detection of an individual depends on species detectability and on the sampling duration. Several models are proposed to describe the influence of these parameters on the relationship between frequency and abundance, but it was not possible to deduce a general model that includes all these parameters. Thus sampling conditions have to be carefully chosen in order to control at least some of these parameters.

The proposed models have been applied to a series of bird censuses performed by Blondel (Terre et Vie, 29 (1975) : 533-589). Species frequencies were determined from 38 samplings and were transformed into species abundances using the models proposed in the first section of this paper. Species abundances derived from the frequencies agree fairly well with species abundances determined by direct sampling. The models proposed may have more general applications to samplings based on the presence or absence of a species.
Les peuplements de vertébrés terrestres des îles Mascareignes
Authors: Moutou François
Published: November 2022

L’existence d’une relation linéaire entre la surface des trois îles de l’archipel des Mascareignes et le nombre d’espèces des trois classes de vertébrés naturellement présents, confirment les vues de MacArthur et Wilson sur les peuplements insulaires.

L’étude comparative des résultats inter-taxons et inter-îles, permet de penser que l’histoire passée des trois îles est différente. L’île Rodrigues et l’île Maurice sont les deux plus anciennes. Les reptiles, peu aptes à se déplacer sur les océans, sont bien représentés à Maurice, mais très mal à la Réunion. Oiseaux et chiroptères dotés de puissants moyens de dispersion, ont rapidement colonisé les trois îles. Cependant les équilibres spécifiques n’étaient probablement solides qu’à Maurice. L’île de la Réunion a perdu beaucoup plus d’espèces que Maurice et l’île Rodrigues a vu ses effectifs décliner à la suite d’une réduction importante de surface.

Le rythme de dégradation du milieu naturel sur les trois îles ne permet pas d’envisager une très longue survie des espèces autochtones encore présentes, à moins qu’une politique de conservation reposant sur des bases vraiment scientifiques soit rapidement mise en œuvre.
La détermination de l’âge individuel chez le Lièvre européen par la technique squelettochronologique
Authors: Pascal Michel , Kovacs György
Published: November 2022

L’observation de coupes histologiques de mandibules réalisées sur 18 lièvres d’élevage (Lepus capensis L.) d’âge connu a montré que le nombre de Lignes d’Arrêt de Croissance (L.A.C.) dans le tiers inférieur des coupes localisées dans la région PM1/PM2 était égale, dans 83 % des cas, à l’âge des sujets en années. L’interprétation que nous avons pu faire de la morphogénèse de la mandibule du Lièvre est très comparable à celle donnée par Bang et Enlow (1967) et Seiton et Engel (1969) chez le Lapin.

La corrélation entre le nombre de L.A.C. dénombrées dans l’os lamellaire périphérique des os longs (phalange, métatarse, tibia) et l’âge réel des animaux n’est pas suffisante pour suggérer de retenir ces pièces osseuses dans le but de déterminer des structures de population. Cependant, il est possible de séparer les jeunes de moins de 9 mois des adultes, fait qui pourrait présenter quelque intérêt pour préciser la nature du régime alimentaire de certains carnivores à partir de fragments osseux contenus dans les fèces.

Le poids des cristallins obtenus sur 160 lièvres hongrois sauvages, croît avec l’âge déterminé par la technique histologique. Cependant, en raison d’une grande variation individuelle du poids du cristallin, ce dernier critère n’est valable que pour de jeunes sujets et n’est guère utilisable pour déterminer avec précision l'âge d'individus de plus de 2 ans
Comparaison des régimes alimentaires du Tétras lyre Lyrurus tetrix (L.) et du Lagopède alpin Lagopus mutus dans le vallon de la Cerveyrette (Hautes-Alpes)
Authors: Bernard-Laurent A.
Published: November 2022

Les régimes alimentaires du Lagopède alpin (Lagopus mutus Montin) et du Tétras lyre (Lyrurus tetrix (L.)), à l’automne, sont comparés à partir de l’analyse des contenus de 34 et 66 jabots respectivement, recueillis dans les vallons de la Cerveyrette et du Blétonnet (Hautes-Alpes), au cours des saisons de chasse 1977 à 1981. Le biotope du Tétras lyre, situé entre 1 850 et 2 300 m (étage subalpin) est constitué d’une mosaïque de bois de mélèzes (Larix decidua) et de prairies. Celui du Lagopède lui succède en altitude ; il est occupé de pelouses alpines pâturées, d’éboulis et de moraines.

Il apparaît que le régime alimentaire automnal du Lagopède, marqué par la dominance des Saules (Salix sp. pl.) est moins varié que celui du Tétras lyre dont la nourriture se compose surtout des fruits et feuilles de 8 espèces végétales, dont 6 d’entre elles sont des phorbes. Cette différence est à mettre en relation avec la richesse plus élevée de la végétation offerte aux tétras qu’aux lagopèdes. La part de la nourriture animale dans le régime alimentaire est négligeable pour le Lagopède alpin et faible pour le Tétras lyre. La composition de la nourriture des tétras lyre et des lagopèdes ne reflète pas l’offre du milieu, indiquant que ces deux Tétraonidés montrent des préférences alimentaires. En outre, pour chaque espèce consommée, le Tétras lyre présente un comportement plus sélectif que le Lagopède, en choisissant certains organes particuliers (fruits, feuilles ou têtes florales).
Recensements aériens des principaux ongulés du Parc National des Virunga, Zaïre
Authors: Mertens H.
Published: November 2022

Un recensement aérien des populations de grands mammifères du Parc National des Virunga (PNVi) a été réalisé en 1980 et 1981. Les techniques utilisées sont décrites et les résultats comparés aux recensements de 1959 et aux dénombrements d’hippopotames de 1959 et de 1974.

Les biomasses animales ont été calculées et font apparaître que les hippopotames représentent actuellement, à eux seuls, plus de 75 % de la biomasse animale totale dans la plaine sud du PNVi.
Dynamique du renouvellement et structure d’âge d’une population d’hermines (Mustela erminea)
Authors: Debrot Sylvain
Published: November 2022

L’étude d’une population d’hermines (Mustela erminea) dans le Val de Ruz (Jura neuchâtelois, Suisse) a permis la capture et le marquage de 95 individus d’avril 1978 à avril 1980. La structure mensuelle moyenne de la population a été établie à partir d’un calendrier de captures intégrant les 178 captures et recaptures réalisées. Un taux de mortalité (TMa ; estimé constant) de 0,68 et un taux de renouvellement (TRa ; dépendant de l’émigration) de 0,93 caractérisent la labilité de la population des adultes. TMa est en accord avec la proportion élevée de juvéniles. TRa traduit le large rayon de dispersion des adultes par rapport aux dimensions du terrain d’étude (616 ha). L’âge moyen de la population active estimée a été calculé pour chaque mois. Il oscille entre 9,8 mois en août et 18,7 mois en mai. La longévité estimée est un peu plus élevée que les valeurs trouvées dans des populations intensivement chassées, mais inférieure à la longévité potentielle de l’espèce. Les hermines du Val de Ruz paraissent donc être soumises à une pression de sélection élevée.
Application de la notion de niveau de perception à l’étude des peuplements d’oiseaux palustres méditerranéens
Authors: Pages J-M.
Published: November 2022

An attempt was made to characterize the communities of breeding birds in three mediterranean areas of Southern France (Languedoc wetlands, Petite Camargue and Grande Camargue). The species lists were drawn up by using the Frequency Sampling method (Echantillonnages Fréquentiels Progressifs, Blondel, 1975). Four levels of perception were considered.

— The station : several variables considered to be important were tested : location and topography of the site, physiognomy and nature of vegetation. — The biotope : Correspondance Analysis enables to identify four categories of biotopes (forests, saline environments, freshwater marshes, dunes) and to understand their interrelations.

— The sector : the relative geographical isolation of the Languedoc wetlands, and the many environmental changes induced by human activities in this area, can explain their lower species richness, as compared to the Grande Camargue.

— The region : geographical variables were used to explain the distribution of water-birds in ten circum-mediterranean wetlands.
Heteroligus meles billberg (Col., Scarabaeidae), un bon matériel d’étude de l’équateur biologique
Authors: Gillon Y. , Ducatillion Catherine
Published: November 2022

The Yam beetle Heteroligus meles is found in tropical Africa both North and South of the equator, and in savannas (in humid areas along watercourses) as well as in rain-forests.

This species is monovoltine in West Africa. Its life-cycle is characterized by two migrating flights : one (the feeding migration) takes place at the beginning of the rains away from the areas where the larvae have developped ; it is effected by imagos of low body weight. The second migration flight (the breeding migration) occurs at the outset of the dry season in a reverse direction and is effected by heavier imagos.

At Makokou (Gabon), which is located South of the climatic equator, but North (0.4°N) of the geographic equator, preliminary observations suggest the coexistence of two sympatric populations of yam beetles, one with a boreal life-cycle and the other with an austral life-cycle — as it is the case for the bat Hipposideros caffer.
Saisonnalité et déterminisme du pic de fructification en forêt guyanaise
Authors: Sabatier Daniel
Published: November 2022

The phenology of flowering and fruiting of trees was studied from June 1980 to the end of March 1982 in the lowland rain forest of Piste Saint Elie, French Guiana. All flowering and fruiting trees over 2 cm DBH overhanging a trail 1000 to 1500 m long and 1 m wide were noted every second week, and all flowers and fruits which fell on the trail were collected and weighed. The following results were obtained :

Fertility was always low, less than 50 % of the trees over 45 cm DBH bearing fruit during the two yearly cycles. Fertility also varied from one year to the next, being higher during the second yearly cycle. However, some trees which flowered normally never bore fruit.

Most tree species (from 76 to 80 %, depending on the year) flowered during the «dry» season and bore fruit during the rainy season (86 to 88 %). The seeds of most of the species (56 %) germinated in less than one month in experimental conditions, and 22,2 % in more than 4 months.

Seasonality in reproduction occured in all species of dicotyledonous trees, whatever their size or age (from 2 to > 60 cm DBH). It was far less marked in understorey trees, epiphytes and woody lianas. Seasonality in fruiting was particularly marked among species bearing fleshy fruits disseminated by animals, although some were produced at any time of the year. Seasonality was also marked among wind-dispersed and autochorous tree species. Among trees bearing fleshy fruits, those with the larger seeds were much more seasonal than those with smaller seeds. Finally, the species which were moderately abundant on the sampling transect were more seasonal than both the scarcer and the most abundant ones. Mast fruiting was observed in 8 species of Eschweilera and Lecythis (Lecythidaceae). In the rain forest studied, the fruiting peak mostly results, at the species level, from the adjustment of the maturation period to the flowering time.

Biotic factors undoubtedly play an important role in determining fruiting peaks at the community level.
Stratégies adaptatives comparées des rolliers (Coracias SP.) Sédentaires et migrateurs dans une savane guinéenne
Authors: Thiollay Jean-Marc
Published: November 2022

Le Rollier à ventre bleu, Coracias cyanogaster, a été étudié en détail en savane préforestière de Lamto (Côte-d’Ivoire). Son comportement social favorise l’exploitation des ressources localisées. Sa chasse à l’affût, et notamment la fréquence des changements de perchoirs, est généralement conforme aux prévisions de la théorie de l'optimal foraging, à l’exception de l’entraînement social du groupe qui augmente la fréquence des déplacements. Plus les proies sont visibles (savane claire), plus le succès de chasse est élevé et plus les déplacements sont réduits (éléments déterminant le choix du milieu). Les circuits de chasse s’effectuent par étapes et décrivent des boucles. Le taux de succès de la chasse diminue en saison des pluies, laquelle est donc aussi pour le sédentaire, la période limitante. La fréquence des attaques est maximale en milieu de matinée et en fin d’après-midi. Un Rollier moyen passe 85 % de la journée (12 h 30) en affût, 7 % au repos, 1,8 % en vols de chasse et captures et 6,2 % en interactions sociales. Il effectue par jour 40 attaques, dont 33 captures pesant au total 7 à 10 g et représentant par mois plus de 1 % de la biomasse disponible des proies exploitées.

Les migrateurs, C. naevia et C. abyssinica, habitent en Côte-d’Ivoire des milieux plus ouverts, à sol plus dégagé que le précédent. Ils chassent sur des perchoirs en moyenne plus bas, qu’ils occupent pendant des périodes plus longues. Ils ont des terrains de chasse individuels plus vastes, un régime alimentaire plus spécialisé et des techniques de capture moins diversifiées que le sédentaire. Ils sont moins bien adaptés que ce dernier aux conditions de la saison des pluies (hauteur et densité de la végétation), ce qui explique alors leur remontée vers le nord où les conditions correspondent mieux à leurs aptitudes.
Evaluation visuelle des peuplements et populations de poissons : méthodes et problèmes
Authors: Harmelin-Vivien M. L. , Harmelin J.G. , Chauvet Claude , Mellon-Duval Capucine , Galzin R. , Lejeune P. , Barnabé Gilbert , Blanc Françoise , Chevalier R. , Duclerc Jean , Lasserre G.
Published: November 2022

Following the symposium held in June 1984 at Port Cros, the methods of underwater observation of fish communities and populations are critically reviewed.

Particular emphasis is laid upon the possible causes of bias, and the ways of circumventing them. Given some necessary precautions and adequate training, and within definite limits, underwater observations and counts can produce highly reliable results, not obtainable by «blind» techniques.

Some examples are given, based upon the personal experiences of the participants, both in the Mediterranean and the Indo-Pacific.
Eco-éthologie des chiens errants. Position du problème
Authors: Lecomte Jacques
Published: November 2022

As an introduction to the session, the author summarizes our present knowledge on the ecology and behaviour of stray and feral dogs. They are far more numerous than commonly realized, especially in Southern Europe and around the Mediterranean. They raise both public health and conservation problems.
The impact of human activities on the food of Red fox and Wolf in Old Castille, Spain
Authors: Reig S. , La Cuesta L. de , Palacios F.
Published: November 2022

An attempt is made to describe the role of anthropogenic factors on the food habits of the Red fox (Vulpes vulpes) and the Wolf (Canis lupus). Two zones differing in habitats and types of land use were chosen in North-Western Spain. A total of 444 and 118 gut contents, from foxes and wolves respectively, was collected. Presence/absence data were obtained and a possible relationship between categories of human activities and food items was looked for by establishing a trophic matrix (gut contents = columns, human activities = rows) to which the Simpson index was applied. The results showed differences between the species in the amount of anthropogenic food, 86 % and 85 % in the Wolf, and 47 % and 48 % in the Fox, for the A and B zones respectively. However, comparing both zones, no significant differences were obtained, suggesting that the main human activity affecting food habits is that brought about by the presence of human settlements ; waste, garbage and associated fauna represent more than 50 % of the total amount of anthropogenic food in both species.
Méthode d’interprétation statistique du rythme d’activité de carnivores suivis par radio-pistage
Authors: Aubert Michel , Artois Marc , Stahl P.
Published: November 2022

The authors describe a method for estimating the circadian activity of radio-tagged animals when fixes are taken during several days at irregular time intervals. This allows a more intensive tracking during periods of intense activity of the tracked animals. Examples of activity diagrams are given. They were obtained by computing data from non rabid and rabid foxes.
The diet of stray dogs in the suburbs of Warsaw
Authors: Romanowski Jerzy
Published: November 2022

138 fécès collectés de novembre 1983 à mai 1984 ont été examinés. Le régime alimentaire indique que les chiens ne jouent qu’un rôle limité de prédateurs des rongeurs dans un environnement péri-urbain où la nourriture principale est constituée par divers déchets.
The epidemiology of hydatid disease in the United Kingdom and Kenya
Authors: McManus D.P. , Smyth J.D. , Macpherson C.N.L.
Published: November 2022

L’hydatidose (échinococcose uniloculaire) causée par la larve d'E .granulosus est endémique en Grande-Bretagne et au Kenya. Il existe en Grande-Bretagne des foyers notables d’infection dans les secteurs d’élevage ovin au sud du pays de Galles et au nord-ouest de l’Ecosse où existe une forte prévalence concordante entre moutons et chiens de ferme. Les renards peuvent jouer un rôle significatif dans le cycle mouton/chien au pays de Galles.

Dans la région du Turkana au nord-ouest du Kenya, l’incidence humaine d’hydatidose est la plus forte du monde. Ceci est en partie lié au grand nombre de chiens errants et domestiques lourdement infestés. Les deux espèces de chacals hébergent le parasite, mais les hôtes intermédiaires sauvages restent inconnus. La prévalence est assez faible chez les bovins, moutons et chèvres et fait unique, l’homme participe potentiellement, comme hôte intermédiaire, au cycle de E. granulosus. Au contraire en pays Masai (sud du Kenya) l’incidence est faible chez l’homme et la prévalence forte chez les espèces domestiques. Un cycle selvatique se perpétue entre les lions, lycaons, chacals et divers ongulés sauvages.

Une souche chien/mouton et une autre chien/cheval de E. granulosus ont été reconnues en Grande-Bretagne. Alors que la première souche est connue pour contaminer l’homme, la spécificité d’hôte précise de la seconde reste indéterminée, quoique des éléments épidémiologiques indirects suggèrent un pouvoir infectieux faible chez l’homme. Au Kenya, la situation des souches est plus confuse car les parasites chien/mouton, chien/homme et la majorité des parasites chien/chèvre sont semblables, et probablement inter-infectieux. Les parasites chien/bétail et surtout chien/dromadaire présentent des différences majeures de la forme chien/homme et leur situation reste mal définie, particulièrement sous l’aspect de la contagion à l’homme.
Les palmiers des forêts tropicales humides du bas Tocantins (Amazonie brésilienne)
Authors: Kahn Francis
Published: November 2022

Vingt et une espèces de palmiers réparties en 9 genres ont été recensées sur 10,56 ha dans des forêts de l’est amazonien, vallée du Tocantins, Etat du Pará. La densité moyenne de palmiers (ou d’axes pour les espèces multicaules) de hauteur égale ou supérieure à 1 m est de 602 par hectare. Une comparaison avec deux autres inventaires situés dans le centre et l’ouest de l’Amazonie révèle la pauvreté en espèces et en genres de palmiers et leur faible densité dans ces forêts de la région orientale.