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dc.contributor.authorHusband, E
dc.date.accessioned2019-06-05T07:41:13Z
dc.date.issued2019-05-28
dc.description.abstractGlobally, coral reefs are experiencing reductions in structural complexity, primarily due to a loss of key reef building taxa. Monitoring these changes is difficult due to the time-consuming nature of in-situ measurements and lack of data concerning coral genus-specific contributions to reef structure. This research aimed to develop a new technique that uses coral colony level data to quantify reef rugosity (a 3-dimensional measure of reef structure) from three sources of coral survey data: 2D video imagery, line intercept data and UAV imagery. A database of coral colony rugosity data, comparing coral colony planar and contour length for 40 coral genera, 14 morphotypes and 9 abiotic reef substrates, was created using measurements from the Great Barrier Reef and Natural History Museum. Mean genus rugosity was identified as a key trait related to coral life history strategy. Linear regression analyses (y = mx) revealed statistically significant (p < 0.05) relationships between coral colony size and rugosity for every coral genus, morphotype and substrate. The gradient governing these relationships was unique for each coral taxa, ranging from mean = 1.23, for (encrusting) Acanthastrea, to m = 3.84, for (vase-shape) Merulina. These gradients were used as conversion factors to calculate reef rugosity from linear distances measured in video transects of both artificial reefs, used as a control test, and in-situ natural coral reefs, using Kinovea software. This calculated, ‘virtual’ rugosity had a strong, positive relationship with in-situ microscale rugosity (r2 = 0.96) measured from the control transects, but not with that measured at the meso-scale in natural, highly heterogeneous reef environments (r2 < 0.2). This showed that the technique can provide accurate rugosity information when considered at the coral colony level. The conversion factors were also applied to historic line intercept data from the Seychelles, where temporal changes in calculated rugosity were consistent with changes in coral cover between 2008 and 2017. Finally, on application to 2,283 corals digitised from UAV imagery of the Maldives, the conversion factors enabled calculation of rugosity for three 100 m2 reef areas and prediction of how this rugosity will decrease during two future scenarios of coral reef degradation and community change. The study highlights that the application of genera-specific coral rugosity data to both new and existing coral reef survey datasets could be a valuable tool for monitoring reef structural complexity over large spatial scales.en_GB
dc.identifier.urihttp://hdl.handle.net/10871/37378
dc.publisherUniversity of Exeteren_GB
dc.rights.embargoreasonI wish to place an embargo on my thesis to be made universally accessible via ORE, the online institutional repository, for a standard period of 18 months because I wish to publish papers using material that is substantially drawn from my thesis. 18 months from my original hand in date is the 11th September 2020.en_GB
dc.subjectCoral reefen_GB
dc.subjectStructural complexityen_GB
dc.subjectrugosityen_GB
dc.subjectcoral colony scale rugosity measurement techniqueen_GB
dc.subject2D to 3D characteristicsen_GB
dc.subjectclimate changeen_GB
dc.subjectcoral degradationen_GB
dc.subjectcoral community changeen_GB
dc.subjectlocal and global disturbanceen_GB
dc.subjectUAV imageryen_GB
dc.subjectin-situ measurementen_GB
dc.titleCoral Colony-Scale Rugosity Metrics and Applications for Assessing Temporal Trends in the Structural Complexity of Coral Reefs.en_GB
dc.typeThesis or dissertationen_GB
dc.date.available2019-06-05T07:41:13Z
dc.contributor.advisorPerry, Cen_GB
dc.publisher.departmentGeographyen_GB
dc.rights.urihttp://www.rioxx.net/licenses/all-rights-reserveden_GB
dc.type.degreetitleMasters by Research in Geographyen_GB
dc.type.qualificationlevelMastersen_GB
dc.type.qualificationnameMbyRes Dissertationen_GB
rioxxterms.versionNAen_GB
rioxxterms.licenseref.startdate2019-05-20
rioxxterms.typeThesisen_GB
refterms.dateFOA2019-06-05T07:41:20Z


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