Characteristics and significance of a sub-tropical 'Low Wooded Island': Green Island, Moreton Bay, Australia

Green Island, Moreton Bay (latitude 27 degrees 25'S), lies 9 degrees south of the highest latitude previously reported for low wooded islands, which a re noteworthy among reef islands for their geomorphic complexity and rarity . Green Island's geomorphic and ecological characteristics closely resemble those of law wooded islands (LWIs) of the northern Great Barrier Reef. Tho se characteristics which differ from the northern Great Barrier Reef exampl es can be largely explained by biological response to the latitudinal tempe rature gradient and to the low energy environment. As a low wooded island 1 200 km south of the southern-most LWI on the GBR and close to the latitudi nal limits of both coral reef growth and high mangrove diversity, Green Isl and may be unique. Previously, low wooded islands have been reported only f rom coral reef environments between latitude 18 degrees N and 16 degrees 23 'S, on high elevation reef flats close to mainland coasts. Although a serio us threat to Green Island's geomorphic and ecological integrity (ie, coral dredging) has been averted, management provisions to ensure the preservatio n of this complex reef island require enhancement.