Marsh terracing is an innovative restoration technique being used in shallow, open water marshes in coastal Louisiana. When properly constructed and planted with an applicable plant species, terraces promote sediment deposition and accumulation by reducing wave energy. Although used extensively for marsh creation, little published information is available on techniques for establishing vegetation on marsh terraces.
The goal of this research was to determine the optimal planting season and most effective plant growth form of Spartina alterniflora for establishing vegetation on newly constructed marsh terraces. Study objectives were to: 1) compare survival and growth rates of different plant growth forms based on planting season, 2) determine the optimal method of handling/storing seed to maximize germination and survival on terraces, 3) characterize soil composition and terrace elevation as compared to ambient marsh, and 4) monitor water depth and salinity of an adjacent water body to determine any relationship to plant response.
This research was conducted on a large-scale terracing project on the Pointe aux Chenes Wildlife Management Area. Vegetative transplants of S. alterniflora were established on the terraces and were quantitatively sampled to examine differences in survival and growth. Treatments included plant growth form: containered plants (trade-gallon) and vegetative plugs; planting season: spring and fall planted; and growth period: 6 and 12 months. There was no significant difference in survival among planting seasons (p=0.0933) or growth forms (p=0.5396). Vegetative plugs and trade-gallons had similar growth rates when comparing aboveground biomass (944.79g/m2 and 1173.39g/m2, respectively) and belowground biomass (1187.82g/m2 and 1262.60g/m2, respectively). In a separate seeding study, there was little germination of S. alterniflora seed on the terraces (less than 1%), though the seed proved to be viable under in controlled germination tests. Although direct seeding is not a viable option on marsh terraces, vegetative transplants of S. alterniflora are effective in establishing vegetation on terraces. This study will add to the knowledge base of coastal restoration technology by evaluating the variability in terrace construction and the hydrologic-soil-plant relationship that is essential to terracing success, thus providing restoration project planners with additional strategies that will better incorporate vegetative establishment into terrace engineering.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-06112007-162947 |
| Date | 12 June 2007 |
| Creators | Mullens, Ashley Wilson |
| Contributors | Maud M. Walsh, Irving A. Mendelssohn, Charles E. Sasser |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-06112007-162947/ |
| 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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