Aspects de l'ornithochorie et de la germination des semences des arbustes en fruticée calcicole de Calestienne

Abstract

Dispersai by birds and germination of seeds from some scrubs in a calcareous shrublandThe thorny shrubland is the mort common évolution stage of ungrazed calcareous grasslands in Western Europe. Shrubs of this thicket bear many fruits which are especially dispersed by birds, according to différent feeding behaviours. Regarding the phenology of the main species, ripe fruits are available during nearly eight months. Some germination tests have been applied to seeds with intention to break possible dormancy phenomenon. The seed of Ligustrum vulgare L. can germinale without any pretreatment. For Prunus spinosa L. and Rhamnus cathartica L., a cold period is required to break dormancy. Other species, like Rosa canina L., or Crataegus monogyna Jacq., demand spécial treatment to break complex dormancies. The role of frugivores seems more to pull down the pulp of the fruit than to break dormancy by passage into digestive system.

Keywords

• calcareous shrubland
• shrubs
• calcareous soil
• germination
• dormancy
• phenology
• frugivorous birds
• Belgium