Factors influencing the colonisation by springtails of great barrier Reef Islands

The Collembola fauna of ten cays of the Swain Reefs (Great Barrier Reef) were sampled in July 1982 and 1983. Marine littoral Collembola were found on all but two cays. Terrestrial Collembola were sampled quantitatively in 1983 on three cays of increasing degrees of vegetation cover. On the largest well-vegetated cay, collembolan numbers were at least twenty-five times higher than on the less well-vegetated cays. Xenylla manusiensis, the overwhelmingly dominant Collembolon among the cays, showed a positive association with organic matter in the sample. A species list for all coral and volcanic islands from which Collembola have been collected in the Great Barrier Reef is supplied with notes on ecology and distribution. Some marine littoral species are recorded here for the first time. A family signature shows that Isotomidae are the relatively most species rich group collected and Symphypleonan families and Entomobryidae the least. Adaptations to a marine littoral life of some species are described. Management options to protect the fauna, especially short-range endemics, are suggested.