MAY 2018 by Lindsay Marion Veazey Dissertation
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DISTRIBUTION MODELING OF MESOPHOTIC CORALS AND ALGAE TO FURTHER ECOLOGICAL UNDERSTANDING AND RESOURCE MANAGEMENT OF HAWAIIAN CORAL REEFS A DISSERTATION SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAIʻI AT MĀNOA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN ZOOLOGY MAY 2018 By Lindsay Marion Veazey Dissertation Committee: Robert Toonen, Chairperson Christopher Kelley Erik Franklin Peter Marko Tamara Ticktin Keywords: species distribution modeling, spatial ecology, mesophotic coral reef ecosystems ACKNOWLEDGMENTS First, I dedicate this manuscript to my parents, whose encouragement, love, hiking companionship, and appreciation of all non-human animal friends strengthened my dedication to the discipline of biological sciences and emboldened my passion for environmental stewardship and animal welfare. The completion of the work presented in this document would not have been possible without the support, conversation, commiseration, patience, and ample good humor of my ʻohana near and far. The attainment of this degree is the culmination of many, many years of curiosity and wonder shared with my friends and family who have resolutely encouraged my pursuit of scientific truth. I dedicate this manuscript to all of you. Finally, to all of the women- particularly women scientists- who confronted a world shaped by and for men, and decided they would do it anyway: my path was clearer because of your resilience. I count the submission of this dissertation as one more seed of progress that may facilitate the realization of a world shaped by strong, tough, educated, and independent women. ii ABSTRACT Hawaiian photic reef ecosystems, found from the surface to 30 m depth, are imperiled by anthropogenic stressors such as climate change, overfishing, introduction of invasive species, and sedimentation from coastal construction. Mesophotic coral ecosystems (MCEs) found from 30 to 180 m may be buffered from these stressors by their deeper depth range. However, their vulnerability is not well known because minimal data exist on their location and community structure around the main islands. Consequently, I developed multiple, spatially explicit models to predict the distribution of important MCE members, which included scleractinians of the genera Montipora and Leptoseris, and the calcified alga Halimeda kanaloana. Similar models were also created for the invasive alga Avrainvillea amadelpha to better understand its potential impact on Hawaiian MCEs. Using the results of my models, I created maps across the main Hawaiian Islands, identifying the most suitable habitat for (i.e., the most probable location for colonization by) these species of interest. These are the first pan-Hawaiʻi predictive distribution maps for corals and algae within the mesophotic zone, which will hopefully serve as a valuable source of information to resource managers, scientists, and stakeholders in future marine spatial planning efforts. iii LIST OF TABLES Table 2.9.1: Number of field observations for each coral genus………………………...………41 Table 2.9.2: List of all variables considered for inclusion in my analyses………………………42 Table 2.9.3: Summary statistics for theoretical semivariogram models…………………………44 Table 2.9.4: Predictive model output…………………………………………………………….44 Table 2.A.1: Summary output for Leptoseris OLR model………………………………………45 Table 2.A.2: Summary output for Montipora OLR model………………………………………45 Table 2.A.3: Summary output for Leptoseris rare events corrected model……………………...45 Table 2.A.4: Summary output for Montipora rare events corrected model………………….…..46 Table 3.8.1: Observational data………………………………………………………………….79 Table 3.8.2: List of considered variables………………………………………………………...79 Table 3.8.3: Included variables…………………………………………………………………..80 Table 3.8.4: Performance statistics of 5 m spatial models.………………………………………81 Table 3.8.5: Performance statistics of 25 m spatial models.……………………………………..82 Table 3.8.6: Performance statistics of 100 m spatial models.……………………………………82 Table 3.8.S1: Variables not included…………………………………………………………….82 Tabkes 3.8.S2 – S13: Descriptive statistics for all GLMs and GLMMs………………………...83 Table 3.8.S14: Summary statistics (5 m)………………………………………………………...87 Table 3.8.S15: Summary statistics (25 m)……………………………………………………….88 Table 3.8.S16: Summary statistics (100 m)………………………………………….…………..89 Table 4.9.1: Observational survey data…………………………………………………………112 Table 4.9.2: Mesophotic survey information…………………………………………………...112 Table 4.9.3: List of considered variables……………………………………………………….112 Table 4.9.4: Model performance details………………………………………………………..113 Table 4.9.5: Influence of predictors in simplified model…………………………………….…114 iv LIST OF FIGURES Figure 2.8.1: The study domain…………………………………………………………….……29 Figure 2.8.2: Modeled spherical semivariogram for Leptoseris……………………...….………29 Figure 2.8.3: Modeled spherical semivariogram for Montipora ………………………..………30 Figure 2.8.4: ROC curves for all models……………………….…………………….……….…31 Figure 2.8.5: Modeled area of suitable habitat for Leptoseris. …………...………….…….……31 Figure 2.8.6: Modeled area of suitable habitat for Montipora…..………...………….…….……32 Figure 2.8.7: Hotspot map for Leptoseris. …………...………………………...…….…….……32 Figure 2.8.8: Hotspot map for Montipora. …………...………………………...…….…….……33 Figure 2.8.9: Hotspot map for Leptoseris and Montipora. …………...………………………....33 Figure 2.A.1: Bathymetry map…………………………………………………………………..34 Figure 2.A.2: Aspect map………………………………………………………………………..35 Figure 2.A.3: Curvature map………………...…………………………………………………..36 Figure 2.A.4: Rugosity map………………...……………………………………………………37 Figure 2.A.5: Slope map………………...…………………………………………...…………..38 Figure 2.A.6: Effect of depth on Leptoseris probability values……………………………….…38 Figure 2.A.7: Effect of northward summer current velocity on Leptoseris probability values….39 Figure 2.A.8: Effect of easteward winter current velocity on Leptoseris probability values……39 Figure 2.A.9: Effect of slope on Leptoseris probability values……………………………….…40 Figure 2.A.10: Effect of rugosity on Leptoseris probability values……….………………….…41 Figure 2.A.11: Effect of depth on Montipora probability values………………………………..41 Figure 2.A.12: Effect of significant wave height on Montipora probability values……………..41 Figure 3.7.1: The geographical extent of the main Hawaiian Islands…………………………...67 Figure 3.7.2: HURL submersible and ROV survey tracks for Leptoseris…………………….…68 Figure 3.7.3: HURL submersible and ROV survey tracks for Halimeda kanaloana……………69 Figure 3.7.4: Correlation scatterplot for Leptoseris (5 m)……………………………………….70 Figure 3.7.5: Correlation scatterplot for Leptoseris (25 m)……………………………………...70 Figure 3.7.6: Correlation scatterplot for Leptoseris (100 m)…………………………………….71 Figure 3.7.7: Correlation scatterplot for Halimeda kanaloana (5 m)……………………………72 Figure 3.7.8: Correlation scatterplot for Halimeda kanaloana (25 m)…………………………..72 Figure 3.7.9: Correlation scatterplot for Halimeda kanaloana (100 m)…………………………72 Figure 3.7.10: Predicted habitat suitability for Leptoseris (5 m)………………………………...73 Figure 3.7.11: Predicted habitat suitability for Leptoseris (25 m)……………………………….74 Figure 3.7.12: Predicted habitat suitability for Leptoseris (100 m)……………………………...75 Figure 3.7.13: Predicted habitat suitability for Halimeda kanaloana (5 m)……………………..76 Figure 3.7.14: Predicted habitat suitability for Halimeda kanaloana (25 m)……………………77 Figure 3.7.15: Predicted habitat suitability for Halimeda kanaloana (100 m)…………………..78 Figure 3.7.16: Goodness of fit results……………………………………………………………79 Figure 4.8.1: Video still of Avrainvillea amadelpha meadow………………………………….105 Figure 4.8.2: Geolocated survey data denoting 23,421 observations of Avrainvillea amadelpha occurrence around Oʻahu…………………………………………………………………….…106 Figure 4.8.3: Video stills of Avrainvillea and Udotea……………………………………………….107 Figure 4.8.4: Observational Avrainvillea data………………………………………………….108 Figure 4.8.5: Correlation scatterplot……………………………………………………………108 Figure 4.8.6: Change in predictive deviance…………………………………………………...109 v Figure 4.8.7: Partial dependence plots…………………………………………………………109 Figure 4.8.8: Predictions of Avrainvillea habitat suitability around Oʻahu……………………110 Figure 4.8.9: Coastal modification compared to Avrainvillea habitat suitability………………111 Figure 4.8.10: Forecasted habitat suitability around the state………………….………………111 Figure 4.8.11: Forecasted changes in habitat suitability around the state……………………...111 vi CONTENTS Acknowledgements……………………………………………………………………………...ii Abstract…………………………………………………………………………………...……..iii List of tables…………………………………………………………………………….…….....iv List of figures……………………………………………………………………………………..v 1. Introduction………………………………………………………………………………..…1 1.1 Painting a picture of the unseen………………………………………………...…………1 1.2 Niche theory……………………………………………………………………………….1 1.3 Ecological modeling: species distributions and habitat suitability………………………..2 1.4 Mesophotic coral ecosystems (MCEs): globally and in Hawaiʻi………………………….3 1.5 Dissertation objectives…………………………………………………………………….4 1.6 References…………………………………………………………………………………5 2. The implementation of rare events logistic regression to predict the distribution of mesophotic hard corals across the main Hawaiian Islands……………………………...12 2.1 Abstract…………………………………………………………………………………..12 2.2 Introduction………………………………………………………………………………13 2.3 Materials and Methods…………………………………………………………………...15 2.3.1 Organismal and environmental data……………………………………………….15 2.3.2 Regression methods………………………………………………………………..17 2.3.3 Model assessment………………………………………………………………….21