The maintenance of populations of the mushroom coral Fungia fungites under different disturbance regimes: sexual versus asexual recruitment

Abstract

The relative contribution of sexual and asexual recruitment to the maintenance of populations of the mushroom coral. Fungia fungites. was investigated under different regimes of disturbance. Disturbances reduced the rates of sexual recruitment, but had little effect on their rates of growth and survival. Conversely, asexual recruits (buds) were produced after disturbances, but their rates of recruitment, growth and survival varied dramatically under the different regimes of disturbance. Asexual recruitment was higher under conditions of chronic sedimentation and frequent-acute disturbances, but survival was very low; whereas, asexual recruitment was lowest following an acute bleaching event, but survival was highest during the calm period that followed. Consequently, asexual recruitment made a greater contribution to population maintenance when an acute disturbance was followed by calm conditions, but sexual recruitment made a far greater contribution in the absence of disturbance, or when populations were exposed to severe-chronic or frequent-acute disturbances. The success of asexual recruitment by corals in response to disturbances is discussed in the light of their exposure to a greater variety and combination of disturbances arising from anthropogenic influences.