Local Extinction in the Bird Assemblage in the Greater Beijing Area from 1877 to 2006

Recent growth in industrialization and the modernization of agricultural activities, combined with human population growth, has greatly modified China’s natural environment, particularly in the vicinity of large cities. We compared avifauna checklists made between 1877 and 1938 with current checklists to determine the extent of local bird extinctions during the last century in the greater Beijing area. Our study shows that of the 411 bird species recorded from 1877–1938, 45 (10.9%) were no longer recorded from 2004–2006. Birds recorded as ‘rare’ in 1938 were more likely to have disappeared in subsequent years. Migrant status also influenced the probability of local bird extinction with winter migrants being the most affected class. Moreover, larger birds were more likely to have disappeared than smaller ones, potentially explained by differential ecological requirements and anthropogenic exploitation. Although our habitat descriptions and diet classification were not predictors of local bird extinction, the ecological processes driving local bird extinction are discussed in the light of historical changes that have impacted this region since the end of the 1930 s. Our results are of importance to the broader conservation of bird wildlife

Biologie de la reproduction et territorialité de trois couas terrestres (Aves, genre Coua, Cuculidés) dans la forêt sèche de l’ouest de Madagascar

Couas (Coua, Cuculidae) are birds endemic to Madagascar. The breeding biology of three terrestrial species (Red-capped C. ruficrista, Cocquerel’s C. coquereli and Giant Coua C. gigas) was studied in two sites (Ampijoroa and Kirindy) of the western dry forest. They are monogamous, faithful to the same partner from year to year and non parasite. Both members of the pair build the nest and raise the young. Because of an important nest predation rate (parti¬ cularly in Coquerel's Coua which builds exposed nests), the young leave the nest early and flee on the ground, where their parents continue to feed them until they are able to fly. From then predation rate lowers. Low fecundity is probably counterbalanced by high adult longevity. Home range size was measured for each species, at different seasons and in habitats which dif¬ fered in their degree of disturbance. Red-capped Coua and Giant Coua have larger home ranges than Coquerel’s Coua. Detailed statistical analyses were possible only for Coquerel's Coua. In Kirindy, mean home range did not differ between logged and unlogged gallery forest, either for unpaired individuals (respectively 3.3 and 3.6 ha in each habitat) or pairs (2.4 ha in each habi¬ tat). On the other hand, mean home range was significantly larger in logged dry forest (5.3 ha for individuals and 8.2 ha for pairs) than in logged gallery forest. In Ampijoroa, individual home ranges were larger in unburned (3.6 ha) than in burned dry forest (2.8 ha) but there was no size difference in home range between unpaired individuals and pairs.Les couas (genre Coua, Cuculidés) sont des oiseaux endémiques de Madagascar. La biolo¬ gie de la reproduction de trois espèces terrestres (Coua à tête rousse C. ruficrista, Coua de Cocquerel C. cocquereli et Coua géant C. gigas) a été étudiée dans deux sites (Ampijoroa et Kirindy) de la forêt sèche de la côte occidentale. Ce sont des coucous non parasites, monogames et fidèles au même partenaire. Les deux parents participent à la construction du nid et à l’élevage des jeunes. Une forte prédation a été remarquée sur les nichées de couas, particulièrement de Coua de Coquerel (Coua coquereli) qui construit des nids facilement accessibles aux prédateurs. Une caractéristique remarquable de ces trois espèces est la poursuite de l’élevage des jeunes au sol, dès qu’ils sont capables de courir mais pas encore de voler. A ce stade, la prédation semble devenir paradoxalement très faible et permet d’atteindre l’âge adulte. Les couas se caractérisent par un faible taux de fécondité, probablement contrebalancé par une grande longévité. La superficie des domaines prospectés par chaque espèce a aussi été mesurée à différentes saisons et en milieu primaire et dégradé. Le Coua à tête rousse et le Coua géant ont des domaines vitaux plus étendus que ceux du Coua de Coquerel. Des comparaisons statistiques détaillées n’ont été possibles que pour le Coua de Coquerel. A Kirindy, la superficie des domaines vitaux de cette espèce ne diffère pas entre la forêt galerie intacte et la forêt galerie dégra¬ dée, aussi bien pour les individus isolés (respectivement 3,3 ha et 3,6 ha) que pour les couples (2,4 ha dans les deux habitats). Mais les domaines vitaux sont significativement plus étendus dans la forêt sèche dégradée (5,3 ha pour les individus et 8,2 ha pour les couples) que dans la forêt galerie dégradée. A Ampijoroa, les domaines vitaux individuels sont plus étendus dans la forêt sèche non dégradée (3,6 ha) que dans la forêt ayant brûlé une f ois (2,8 ha) mais il n’existe pas de différence de superficie entre les domaines des couples et ceux des individus isolés.Chouteau Philippe. Biologie de la reproduction et territorialité de trois couas terrestres (Aves, genre Coua, Cuculidés) dans la forêt sèche de l’ouest de Madagascar. In: Revue d'Écologie (La Terre et La Vie), tome 58, n°2, 2003. pp. 217-242

The impact of burning on the microhabitat used by two species of couas in the western dry forest of Madagascar

Habitat structure — an important consideration in all ecological studies of relationships between animals and their environment — can be studied at different scales. This topic was studied at the microhabitat scale in burned and unburned plots of a dry forest of Madagascar. The response of two endemic terrestrial coua (Coua coquereli and C. ruficeps) to burning was studued, at a microhabitat scale (involving the definition of several microhabitat variables relating to foraging sites of the two species), by comparing burned and unburned plots in a dry forest of Madagascar. There were significant differences between burned and unburned plots in terms of the microhabitat variables that were measured. The two species responded differently to the burning effect. In unburned forest, Coquerel's Coua (Coua coquereli) was restricted to places where tree dispersion and stem density were the most important variables in their foraging sites. The Redcapped Coua Coua ruficeps foraged more often at places where understorey vegetation was not well developed. Burning was not beneficial for Coquerel's Coua, because this species was restricted to favourable foraging sites and had to increase its territory size to find its food. Burning may be favourable for the Red-capped Coua, by increasing prey detectability. Ostrich 2007, 78(1): 43–4

ETUDE DE LA RELATION ENTRE LE VIRUS DE L'HEPATITE B ET SA CELLULE HOTE (ANALYSE DE LA SPECIFICITE D'ESPECE ET DE L'INFLUENCE DU STATUT MARTIAL DE L'HEPATOCYTE SUR LA REPLICATION VIRALE)

RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF