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- Title
Les communautés d'abeilles sauvages dans les habitats protégés méditerranéens : diversité, interactions et co-occurrence avec l'abeille domestique.
- Authors
ROPART, Lise
- Abstract
The French Mediterranean basin is a mosaic of territories including urban and industrialized areas and natural or semi-natural habitats among which numerous protected areas such as National Parks. These Mediterranean protected areas shelter a very diverse flora which is attractive for many flower-visitors. Thereby, many beekeepers also install their honey bee colonies, Apis mellifera L. in these territories. Confronted with the growing demand to settle beehives, managers of protected areas question the consequences of the installations of high densities of honey bee colonies on wild bee communities. To explore these consequences, it was essential to first estimate the diversity of pollinator species as well as their ecological traits, and their interactions with the local wild flora in the territory of the Calanques National Park. Thus, through the compilation of field campaigns on a 10-yr period, nearly 250 species of pollinators (Apoidea, Syrphidae and Bombyliidae) have been identified. These inventories also reported for the first time the existence of a bee species never previously detected in France, Nomada rubricoxa (Hymenoptera: Apidae) and a new hoverfly species, still not described -- Pelecocera sp. (Diptera: Syrphidae). Then, the factors which could structure wild bee communities were explored. I showed that small bees (body length <1.2 cm) were sensitive to both the composition of the local plant community and to the land cover composition within a 1 km radius while large bees (body length > 1.2 cm) were sensitive to land cover composition within a 1 km radius and to the density of honey bee colonies. Indeed, specific richness and abundance of large wild bees decreased with the increase in the density of honey bee colonies suggesting a competition for floral resources. This result was confirmed by studying the foraging behavior of honey bees and wild bees on the three dominant plant species of the garrigue: grey-leaved cistus, Cistus albidus L.; thyme, Thymus vulgaris L.; and rosemary, Rosmarinus officinalis L. The competition for floral resources resulted in a competitive exclusion of large wild bees and a change in the floral diet of small wild bees and bumblebees. The intensity of this competition was greater in the early spring when rosemary was in bloom. Finally, a first estimation of the quantity of available floral resource (nectar and pollen) was provided across the territory of the Calanques National Park by focusing on grey-leaved cistus, thyme and rosemary. These results indicated that the resources produced by these three species are not sufficient to cover the food requirements of honey bees installed in the park's territory. This thesis highlights the consequences of beekeeping activities -- at high densities -- on wild bee communities within Mediterranean protected habitats. Considering the importance of these habitats for the conservation of wild pollinator communities, this thesis also proposes management advices to allow the maintenance of beekeeping activities while preserving the wild pollinator fauna. It also exposes new perspectives relative to the needs to deepen knowledge on the ecological traits of pollinator species as well as to develop new methods to detect competition and to create new tools to estimate the quantities of floral resources available at a territory scale.
- Subjects
MEDITERRANEAN Region; HABITAT conservation; HONEYBEES; BEEKEEPERS; PROTECTED areas; POLLINATORS
- Publication
Ecologia Mediterranea, 2020, Vol 46, Issue 2, p108
- ISSN
0153-8756
- Publication type
Article