Long-term data with high-precision chronology are essential to elucidate past ecological changes on coral reefs beyond the period of modern-day monitoring programs.
In 2012 we revisited two inshore reefs within the central Great Barrier Reef, where a series of historical photographs document a loss of hard coral cover between c.1890–1994 AD.
Living faviid colonies are also present, with the majority being small ( in c.1890. Elevation transects were (a) 250 m long) (starting ~1,020 m from shore) for Bramston Reef, and (b) 280 m long (starting ~110 m from shore) for Stone Island, running perpendicular from the shore to the location of the historical photographs at the reef crest.
In the photograph on the left, Saville-Kent described the large conspicuous faviids as being ‘thickly crowded’ with ‘ovate symmetry and peculiar incidence…(that) if transported to an ordinary landscape, they would pass for a flock of sheep.’ (p.15) Photographs of Bramston Reef taken in 1994 (c) looking south-east towards Gloucester Island (GI) and (d) looking north-east towards Stone Island (SI) [Photographer: A. (e,f) Modern photographs taken during this study in 2012 at the same locations as the photographs taken in 1994 (Photographers: H. Note that most of the reef flat and reef crest for both reefs is below mean low water spring (MLWS) height (0.67 m LAT) which is considered the upper limit of open water coral growth (with the exception of the start of the elevation transect at Stone Island).
Nevertheless, increased replication and high-resolution isotopic dating is helping to overcome these limitations.