Scale dependence of coral reef oases and their environmental correlates.


In Press
Elahi, R.,Edmunds, P. J.,Gates, R. D.,Kuffner, I. B.,Barnes, B. B.,Chollett, I.,Courtney, T. A.,Guest, J. R.,Lenz, E. A.,Toth, L. T.,Viehman, S., andWilliams, I. D.


Ecological Applications


Identifying relatively intact areas within ecosystems, and determining the conditions favoring their existence, is necessary for effective management in the context of widespread environmental degradation. In this study, we used 3,766 surveys of randomly selected sites in the United States and U.S. Territories to identify the correlates of sites categorized as ‘oases’ (defined as sites with relatively high total coral cover). We used occupancy models to evaluate the influence of ten environmental predictors on the probability that an area (21.2 km2 cell) would harbor coral oases defined at four spatial extents: cross-basin, basin, region, and subregion. Across all four spatial extents, oases were more likely to occur in habitats with high light attenuation. The influence of the other environmental predictors on the probability of oasis occurrence were less consistent and varied with the scale of observation. Oases were most likely in areas of low human population density, but this effect was evident only at the cross-basin and sub-regional extents. At the regional and sub-regional extents oases were more likely where seasurface temperature was more variable, whereas at the larger spatial extents the opposite was true. By identifying the correlates of oasis occurrence, the model can inform the prioritization of reef areas for management. Areas with biophysical conditions that confer corals with physiological resilience, as well as limited human impacts, likely support coral reef oases across spatial extents. Our approach is widely applicable to the development of conservation strategies to protect biodiversity and ecosystems in an era of magnified human disturbance.

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Journal Article

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