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A REGIONAL MODEL TO PREDICT CORAL POPULATION DYNAMICS IN RESPONSE TO EL NIÑO–SOUTHERN OSCILLATION
Author(s) -
Fong Peggy,
Glynn Peter W.
Publication year - 2000
Publication title -
ecological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.864
H-Index - 213
eISSN - 1939-5582
pISSN - 1051-0761
DOI - 10.1890/1051-0761(2000)010[0842:armtpc]2.0.co;2
Subject(s) - acanthaster , coral , population , reef , upwelling , ecology , coral reef , oceanography , geography , environmental science , el niño southern oscillation , predation , sea surface temperature , climatology , geology , biology , demography , great barrier reef , sociology
The objective of this paper was to modify an existing size‐structured population model for the coral Gardineroseris planulata developed from field measurements at the Uva Island reef, Panama, for use at the regional scale (Tropical Eastern Pacific). The modified model can be used to aid in prediction of changes in coral population dynamics in response to ENSO events of different frequency and magnitude. The earlier model incorporates coral growth, predation by the sea star Acanthaster planci , and mortality associated with El Niño–Southern Oscillation (ENSO) events. The regional model was modified from the earlier local version by extending the coral growth–temperature relationship to include the lower temperatures observed in areas of strong seasonal upwelling. In addition, ENSO‐associated mortality was modified by incorporating a dynamic function that relates partial mortality of corals in different size classes to the rate of temperature change during an ENSO event. This function is based on data from three reef areas (Uva Island and the Pearl Islands, Panama, and the Galápagos Islands, Ecuador), which represent a regional gradient from an area characterized by relatively high annual temperature with low variability to areas with lower annual temperature subject to seasonal upwelling. Model predictions of coral population size structure in different areas agreed with field observations. Predictions for coral recovery after an ENSO event were most accurate for the Uva Island population and least accurate for the Galapágos Islands population. We also tested the effect of various ENSO frequencies on the size structure of the coral population. Increasing ENSO frequency in the upwelling area resulted in an increase in the proportion of small colonies, while the same increase in ENSO frequency in the thermally stable reef area had little effect on the population. Sensitivity analysis suggested that more accurate estimates of growth of the smallest and largest colonies in upwelling areas as well as predation on intermediate‐size colonies are important to improve predictive capability.