Tournée du groupe Pro Silva Méditerranée le 30 mars 2001 en Ardèche - Pour une foret méditerranéenne durable

Cette tournée a été l'occasion pour le groupe Méditerranéen de Pro Silva de se retrouver en forêt communale de Bourg Saint Andéol en Ardèche. L'objectif de la journée était de passer en revue quelques alternatives de gestion, différentes de celle pratiquée traditionnellement dans les chênaies méditerranéennes, se résumant la plupart du temps à une coupe rase de taillis tous les 30 à 40 ans

Mating skew in Barbary macaque males: the role of female mating synchrony, female behavior, and male–male coalitions

A fundamental question of sexual selection theory concerns the causes and consequences of reproductive skew among males. The priority of access (PoA) model (Altmann, Ann NY Acad Sci 102:338–435, 1962) has been the most influential framework in primates living in permanent, mixed-sex groups, but to date it has only been tested with the appropriate data on female synchrony in a handful of species. In this paper, we used mating data from one large semi-free ranging group of Barbary macaques: (1) to provide the first test of the priority-of-access model in this species, using mating data from 11 sexually active females (including six females that were implanted with a hormonal contraceptive but who showed levels of sexual activity comparable to those of naturally cycling females) and (2) to determine the proximate mechanism(s) underlying male mating skew. Our results show that the fit of the observed distribution of matings with sexually attractive females to predictions of the PoA model was poor, with lower-ranking males mating more than expected. While our work confirms that female mating synchrony sets an upper limit to monopolization by high-ranking individuals, other factors are also important. Coalitionary activity was the main tactic used by males to lower mating skew in the study group. Coalitions were expressed in a strongly age-related fashion and allowed subordinate, post-prime males to increase their mating success by targeting more dominant, prime males. Conversely, females, while mating promiscuously with several males during a given mating cycle, were more likely to initiate their consortships with prime males, thus reducing the overall effectiveness of coalitions. We conclude that high-ranking Barbary macaque males have a limited ability to monopolize mating access, leading to a modest mating skew among them

Estrogen and Progestogen Correlates of the Structure of Female Copulation Calls in Semi-Free-Ranging Barbary Macaques (Macaca sylvanus)

Females of many Old World primates produce conspicuous vocalizations in combination with copulations. Indirect evidence exists that in Barbary macaques (Macaca sylvanus), the structure of these copulation calls is related to changes in reproductive hormone levels. However, the structure of these calls does not vary significantly around the timing of ovulation when estrogen and progestogen levels show marked changes. We here aimed to clarify this paradox by investigating how the steroid hormones estrogen and progesterone are related to changes in the acoustic structure of copulation calls. We collected data on semi-free-ranging Barbary macaques in Gibraltar and at La Forêt des Singes in Rocamadour, France. We determined estrogen and progestogen concentrations from fecal samples and combined them with a fine-grained structural analysis of female copulation calls (N = 775 calls of 11 females). Our analysis indicates a time lag of 3 d between changes in fecal hormone levels, adjusted for the excretion lag time, and in the acoustic structure of copulation calls. Specifically, we found that estrogen increased the duration and frequency of the calls, whereas progestogen had an antagonistic effect. Importantly, however, variation in acoustic variables did not track short-term changes such as the peak in estrogen occurring around the timing of ovulation. Taken together, our results help to explain why female Barbary macaque copulation calls are related to changes in hormone levels but fail to indicate the fertile phase

Action collective, épreuves et apprentissages d'un bien commun : résultats d'une recherche intervention

National audienceLe chapitre 17 rapporte les résultats d'une recherche action menée en Rhônes Alpes en 2004/2005 auprès d'un groupe d'éleveurs en production laitière des Monts du Lyonnais. Il montre la mise en place d'apprentissages, qui permettent la création d'un Bien Commun Local partagé, mais inhibent aussi d'autres possibilités

Tournée du groupe Pro Silva Méditerranée le 30 mars 2001 en Ardèche - Pour une foret méditerranéenne durable

International audienceCette tournée a été l'occasion pour le groupe Méditerranéen de Pro Silva de se retrouver en forêt communale de Bourg Saint Andéol en Ardèche. L'objectif de la journée était de passer en revue quelques alternatives de gestion, différentes de celle pratiquée traditionnellement dans les chênaies méditerranéennes, se résumant la plupart du temps à une coupe rase de taillis tous les 30 à 40 ans