Integral Projection Models and analysis of patch dynamics of the reef building coral Monstastraea annularis
Year: 2011
Type: dissertation
Abstract: Over the past 40 years, coral cover has reduced by as much as 80%. At the same time,\nCoral Reefs are coming under increasing threat from hurricanes, as climate change is\nexpected to increase the intensity of hurricanes. Therefore, it has become increasingly\nimportant to understand the effect of hurricanes on a coral population.\nThis Thesis focuses on the reef-building coral Montastraea annularis. This species\nonce dominated Caribbean Coral Reefs, but is fast being replaced by faster growing\nmore opportunistic species. It is important that the underlying dynamics of the decline\nis understood, if managers stand any chance of reversing this decline.\nThe aim of this Thesis is to investigate the effect of hurricane activity on the dynamics\nof the reef-building coral Montastraea annularis. To achieve this the Integral Projection\nModel (IPM) method was adopted and the results compared to those produced using the\nmore traditional method of Population Projection Matrix (PPM) method.\nThe models were fitted using census data from June 1998 to January 2003, which\ndescribed the area of individual coral patches on a sample of ramets on Glovers Reef,\nBelize. Glovers Reef is a marine reserve that lies 30km off the coast of Belize and 15km\neast of the main barrier reef. Three hurricanes struck Glovers Reef during the study:\nHurricane Mitch (October 1998), Hurricane Keith (September 2000) and Hurricane Iris\n(October 2001).\nThe data have been divided by two different methods in order to test two research\nquestions, firstly if the initial trauma following a hurricane affects the long term dynamics\nof a population and, secondly, if the dynamics exhibited during a hurricane varied with\nhurricane strength.\nIn this Thesis five main results are shown:\n1. All models for all divisions of data are in long term decline.\n2. As initial trauma increased, the long term growth rates decreased, conversely the\nshort term extremes increased.\n3. Fragmentation is more likely as patch size increased and more likely under stronger\nhurricanes.\n4. Integral Projection Modelling painted a similar picture to Population Projection\nMatrix models and should be a preferred method of analysis.5. Interaction of the IPMs can be used to model the changing occurrence of hurricanes\nunder climate change. It is shown that with increased intensity, the population\ncould become extinct 6.3 years sooner.\nThis research is the first step in modelling coral patch populations by the IPM\nmethod. It suggests possible functional forms and compares the results with the PPM\nmethod. Further research is required into the biological functions which drive fragmentation,\nthe method by which large patches divide into groups of smaller patches. The\nconclusions from this Thesis add to the growing body of knowledge concerning the response\nof coral species to hurricanes, focusing on the importance of understanding patch\ndynamics, in order to understand colonial dynamics.
Author: Heather Burgess
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W857669889