The mangrove forest gap dynamic model, FORMAN, was the first individual-based model (IBM) to simulate the long-term successional dynamics of three Caribbean mangrove species, Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle. Assumptions under the spatially implicit approach of gap dynamic models limit their application to small-scale simulations. An expanded, spatially-explicit version of FORMAN was developed to allow for simulations of larger spatial grids, through the inclusion of localized soil conditions and neighborhood-based light resource competition. This expanded model was used to investigate the influence of localized interactions and disturbances of varying size on forest dynamics. A data-model comparison using field data from the Shark River Estuary in the Florida Coastal Everglades (FCE) tested the models ability to predict spatial relationships (inter-tree distances) based on tree size and species. The structure and function of the simulated mangrove forests were sensitive to complex interactions between localized soil and light competition based on neighboring trees. Under spatially varying soil conditions, neighborhood-based light competition limited tree growth (especially that of A. germinans and L. racemosa) in favorable soil zones, while allowing for sapling establishment in less optimal habitats. Forest recovery rates following disturbance were sensitive to both soil stress and disturbance size. L. racemosa experienced the greatest increase in annual productivity following disturbance, and exhibited a positive relationship between post-disturbance structure (biomass and basal area) and disturbance size. There was good agreement between the model and field data for frequencies of inter-tree distances and for the distribution of inter-tree distances when examined by size-class and by each species within sizes classes. However, there were no consistent differences or trends in inter-tree distance probability distributions observed across size-classes or for species within size-classes. The expanded FORMAN model, while still limited to the km2 scale in scope, is a very first step in increasing its spatial capability beyond the gap scale. This expansion potential is important in the context of climate change, as IBMs have been suggested as potentially useful tools in identifying and minimizing inaccuracies resulting from current methods of scaling biomass and productivity estimates from site to continental scales.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-01052017-153724 |
| Date | 18 January 2017 |
| Creators | Hurff, Kieley Shannon |
| Contributors | Rivera-Monroy, Victor Hugo, Rose, Kenneth A, Twilley, Robert R |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf, application/octet-stream |
| Source | http://etd.lsu.edu/docs/available/etd-01052017-153724/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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