Community structure, succession and development of coral reefs in Hawaii

Abstract

Reef building corals in the Hawaiian Archipelago consist of only 42 species belonging to 16 genera. The Hawaiian coral fauna is highly depauperate relative to the Indo-West Pacific Ocean, a result most likely due to geographic isolation. Although impoverished, the species composition of reef building corals is remarkably uniform throughout the archipelago. Differences in species composition which do exist appear to be caused by varying patterns of disturbance and recruitment. Although patchy distributional patterns exist within islands, the differences in species composition between islands are small. Where adequate substrata prevail within the euphotic zone most species are present. Hence species composition tends to be an all or none phenomenon. Contrary to most terrestrial ecosystems, a positive correlation does not exist between species richness and habitat area (0 to 20 m). This may be due to low habitat complexity within the zone for reef building corals and high rates of recruitment between islands. It also suggests that most reef building corals in Hawaii are generalized species. The fact that most do not drop out moving northwestward in the chain is evidence of their generalized life history (eurytopy). The most significant differences between coral reefs found on different islands, are differences in community structure. On seaward reefs differences in community structure appear to be primarily caused by differences in physical disturbance from long period swell; they can b e interpreted as differences in successional age. Moving northwestward within the chain, coral growth rates steadily decline. This has the effect of lengthening the successional process and increasing the likelihood of intervening disturbance. A hypothetical model operational over generations is presented demonstrating the effect of disturbance on the successional process for coral reefs in general. The development of large-scale morphological features such as spurs and grooves, fringing and barrier reefs and atolls involve processes operational over geological periods of time. The chronology of the Hawaiian Archipelago is now sufficiently well known to serve as a time scale against which the development of these structures can be measured.

Hydrology, plankton, and corals of the Maracajaú reefs (Northeastern Brazil): an ecosystem under severe thermal stress

“…The low coral diversity in Maracajaú, compared to other reef systems in Brazil is the consequence of the monopolization of niches by one or few species. According to Grigg (1983), reef systems with low diversity are considered climax communities, space have been dominated by one or two species as a result of their competitive superiority in the absence of frequent disturbance. According to Connell (1980), Ricklefs (1980), and Wilson (1992), disturbance rather than stability seems to enhance the species richness under certain conditions.…”

The Coral Reefs of Eilat — Past, Present and Future: Three Decades of Coral Community Structure Studies

“…I have suggested (Loya 1976a) that the unpredictable low tides at Eilat act as a diversifying force in a way similar to storm and swell damage in Hawaii (Grigg and Maragos 1974;Grigg 1983), and the extreme tidal exposures of reef flats off the Pacific coast of Panama (Glynn 1976). Connell's (1978) 'intermediate-disturbance' hypothesis, stating that the highest diversity of natural communities will be maintained in areas suffering intermediate disturbances on the scales of frequency and intensity, fits these examples.…”

Community structure of hermatypic corals at Pearl and Hermes Atoll, Northwestern Hawaiian Islands: unique conservation challenges within the Hawaiian archipelago

“…In addition, more widespread surveys conducted by Maragos et al (004) throughout the Northwestern Hawaiian Islands (NWHI, Fig. 1) indicate that the relatively uniform species inventories reported by Grigg (1983) at southwest seaward sites simplify a richer and more spatially complex coral fauna. At Pearl and Hermes Atoll, for example, 1 species were observed by Grigg (1983) while 3 were reported by Maragos et al (004).…”

“…Originating over a relatively fixed point of upwelling lava ("hotspot") in the Pacific Plate, the islands, banks and atolls of the Archipelago have developed over at least 7 million years (Dalrymple et al, 1977) through gradual erosion and subsidence as they slowly drift to the northwest by sea-floor spreading (Wilson 1963, Grigg 198, 1997. Grigg (1983) discerned several trends in coral community structure across the Hawaiian Archipelago, including a decrease in coral cover tending northward in the chain and a varying degree of dominance by species that are widely distributed throughout the chain. Grigg's surveys throughout the Archipelago were conducted primarily along southwest seaward reefs at depths close to 10 m, however, and do not necessarily characterize coral communities subject to different regimes of salient environmental parameters, including wave energy, temperature, light and sedimentation.…”