An evaluation of the role of macroalgae in mangrovedieback at Whyte Island, Moreton Bay, subtropicaleastern Australia

摘要

The macroalgal/cyanobacterial assemblages of the Whyte Island mangal on the sub-tropical east Australian coast were investigated to determine if these assemblages hadeither contributed to, or had resulted from, mangrove dieback on the landward margin ofthe community. Habitat disturbance in the area is indicated by: lowered abundances ofspecies of the red algal genera Bosttychia, Caloglossa, Catenella and Murrayella; thepresence of green algal species under the mangal canopy; and a well developedmicrobial mat in the ponded area. None of these features are characteristic of healthymangals in the Moreton Bay region. Impacts at Whyte Island from the ponding of water,discharge of sewage effluent, onshore algal blooms, and drifts from offshore blooms arediscussed as possible causal factors for mangrove dieback. Algae and cyanobacteriarespond quickly to environmental disturbance by showing a shift in species compositionand abundance thereby providing a useful and much needed tool in assessing, under-standing and dealing with perturbations in marine ecosystems.