Revealing secondary seed removers: results from camera trapping

摘要

AbstractThis paper reports the results of the first study on secondary seed removal of seeds dispersed by Sykes' monkeys (Cercopithecus albogularis) using camera traps in Africa. Patterns of primary seed dispersal are often superimposed by secondary conveyance, emphasising the need to study these secondary processes carefully. As the agents and mechanisms of seed dispersal are often concealed, being carried out by cryptic or nocturnal animals in dense vegetation, camera trapping was deemed a viable means to investigate secondary removal of seeds disseminated by C. albogularis in the Western Soutpansberg, South Africa. Camera traps were established at preferred feeding trees of the focal Sykes' monkey group to identify animal species that remove seeds and fruits spat and dropped to the forest floor and seed removal observations were carried out. This method proved to be effective in identifying seed removers and also allowed to get indications about the quantities of seeds removed. Ten animal species were recorded visiting the trees, of which eight were observed removing seeds and fruits. Overall seed and fruit removal rates were high, indicating that the foraging behaviour of C. albogularis attracts many terrestrial frugivores. ResumeCet article donne les resultats de la premiere etude portant sur l'enlevement secondaire des semences dispersees par les cercopitheques de Sykes (Cercopithecus albogularis), realisee en Afrique avec des pieges photographiques. Des transferts secondaires se superposent souvent aux schemas de dispersion primaire, ce qui montre bien la necessite d'etudier soigneusement ces processus secondaires. Comme les agents et les mecanismes de la dispersion des graines sont souvent caches, etant le fait d'animaux cryptiques ou nocturnes qui agissent dans une vegetation dense, on a estime que les pieges photographiques etaient un moyen viable d'etudier le prelevement secondaire des semences disseminees par C. albogularis dans le Western Soutpansberg, en Afrique du Sud. On a place des pieges photos pres des arbres ou le groupe de cercopitheques de Sykes qui nous interessait se nourrit de preference, pour identifier les especes animales qui enlevent les graines et les fruits craches et rejetes sur le sol de la foret et on a ainsi pu realiser cette etude. Cette methode s'est averee efficace pour identifier les especes concernees et a aussi permis d'avoir des indications sur la quantite de graines emportees. On a pu enregistrer le passage de dix especes animales pres des arbres, dont huit furent observees en train de prelever des graines et des fruits. Le taux global de prelevement des graines et des fruits etait eleve, ce qui montre que le comportement alimentaire de C. albogularis attire de nombreux frugivores terrestres.