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Comparing Environmental Influences on Coral Bleaching Across and within Species using Clustered Binomial Regression
Citation:
YEE, S. H., D. L. SANTAVY, AND M. G. BARRON. Comparing Environmental Influences on Coral Bleaching Across and within Species using Clustered Binomial Regression. ECOLOGICAL MODELLING. Elsevier Science BV, Amsterdam, Netherlands, 218(1-2):162-174, (2008).
Impact/Purpose:
Developing models by clustered binomial regression method in order to compare environmental effects on coral bleaching
Description:
Differential susceptibility among reef-building coral species can lead to community shifts and loss of diversity as a result of temperature-induced mass bleaching events. However, the influence of the local environment on species-specific bleaching susceptibilities has not been quantified. We evaluate environmental influences on coral colony bleaching over an eight year period in the Florida Keys, USA> Clustered binomial regression is used to develop models incorporating species-specific responses to the environment in order to identify conditions and species for which bleaching is likely to be severe. Environmental variables, including elevated sea temperature and solar radiation, explained much of the variability in colony bleaching across space and time. Incorporating coral community comparison improved the predictive ability ofthe environmental model However, environment alone did not accurately reproduce the observed levels of bleaching for individual coral species, unless species-specific responses to the environment were included in models. Species-specific models indicated individual coral species responded differently to local environmental conditions and had different sensitivites to temperature-induced bleaching. The probability of colony bleaching incrased with elevated temperature for all species, often as a threshold response, but the severity of the response differed among species. For many coral species, bleaching was exacerbated by high solar radiation. A reduced probability of bleaching under high solar radiation or in shallow locations for other species suggested an abilit to acclimatize to local conditions. Synthesis and applications: Our results indicate the likelihood of mass bleaching events depends on both the local coral community composition and environmental conditions. Model development provides a useful tool for coral reef management by quantifying the inluence of the local environment on species-specific bleaching sensitivies, identifying susceptible species, and predicting the likelihood of mass bleaching events with changing environmental conditions.