EXAMINING PATTERNS IN CORAL DEMOGRAPHIC EVENTS IN PAPAHĀNAUMOKUĀKEA MARINE NATIONAL MONUMENT

Date
2021-12
Authors
Bonis-Ericksen, Nola Keilani
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Burns, John hr
Department
Tropical Conservation Biology & Environmental Science
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Abstract
Identifying drivers of coral resilience and survival is critical for predicting how coral reefs will respond to changing environmental conditions. Coral reef researchers have historically struggled to temporally quantify fine-scale changes in live coral patches, such as growth and partial mortality, due to the difficulty involved in high resolution underwater mapping of coral habitats. Demographic events, including growth, shrinking, recruitment, mortality, fission, and fusion are important changes that occur in live coral patches that are indicative of capacity for resilience. The objectives of this study were to 1) examine high resolution time-series imagery collected at two timepoints to quantify these changes in coral patches (shrinking, growth, fission, fusion, mortality, recruitment) in Papahānaumokuākea Marine National Monument (PMNM), and 2) statistically explore how coral patch characteristics (size and genus) and site characteristics (coral cover and reef complexity) influence the occurrence of these demographic events. This project tracked 2409 coral patches from multiple reef sites across two timepoints spanning from 2016 to 2019. Reef characteristics associated with positive (growth, recruitment) or negative events (mortality, shrinkage) were quantified to identify drivers of coral patch resiliency. Logistic regression modeling revealed that reefs composed of larger coral patches and reefs with greater structural complexity values were associated with lower predictive probabilities of mortality events. Reef complexity, patch size, and genus were found to be statistically significant indicators of reef resiliency (growth, recruitment, survival). These findings can benefit reef management programs by providing bioindicators of reef resiliency that can be incorporated into an array of monitoring efforts to enhance our capacity to conduct vulnerability assessments of these important ecosystems.
Description
Identifying drivers of coral resilience and survival is critical for predicting how coral reefs will respond to changing environmental conditions. Coral reef researchers have historically struggled to temporally quantify fine-scale changes in live coral patches, such as growth and partial mortality, due to the difficulty involved in high resolution underwater mapping of coral habitats. Demographic events, including growth, shrinking, recruitment, mortality, fission, and fusion are important changes that occur in live coral patches that are indicative of capacity for resilience. The objectives of this study were to 1) examine high resolution time-series imagery collected at two timepoints to quantify these changes in coral patches (shrinking, growth, fission, fusion, mortality, recruitment) in Papahānaumokuākea Marine National Monument (PMNM), and 2) statistically explore how coral patch characteristics (size and genus) and site characteristics (coral cover and reef complexity) influence the occurrence of these demographic events. This project tracked 2409 coral patches from multiple reef sites across two timepoints spanning from 2016 to 2019. Reef characteristics associated with positive (growth, recruitment) or negative events (mortality, shrinkage) were quantified to identify drivers of coral patch resiliency. Logistic regression modeling revealed that reefs composed of larger coral patches and reefs with greater structural complexity values were associated with lower predictive probabilities of mortality events. Reef complexity, patch size, and genus were found to be statistically significant indicators of reef resiliency (growth, recruitment, survival). These findings can benefit reef management programs by providing bioindicators of reef resiliency that can be incorporated into an array of monitoring efforts to enhance our capacity to conduct vulnerability assessments of these important ecosystems.
Keywords
Environmental science, Conservation biology, Ecology, coral, demography, reef, resiliency, Structure-from-Motion photogrammetry
Citation
Extent
51 pages
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