Vegetation, Soil Characteristics and Growth of Earthen Terraces in Seven Terrace Fields of Southwestern Louisiana
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PRESENTATION
Mark A. Ford(1,2), Brent J. Hoffpauir(1), and George Melancon(3)
(1) McNeese Wetlands Station
McNeese State University
Lake Charles, LA
(2) Current affiliation: Coalition to Restore Coastal Louisiana
Baton Rouge, LA
(3) Rockefeller Refuge
La Dept Wildlife and Fisheries
Grand Chenier, LA
Abstract
Seven earthen terrace fields ranging in age from 13 years to 1 year were examined in southwestern Louisiana. Lateral growth of the vegetation, measured from the crowns, soil bulk density and soil percent organic material was measured at each of 10 terraces at each site. Terraces were selected randomly, with no regard to compass orientation. The oldest, at Sabine National Wildlife Refuge, had the largest lateral growth. However, there were significant differences (p=0.019 and 0.003) between the un-trenched side and the trenched side where construction materials were borrowed in two different ponds of the same age. In general, the vegetation on the un-trenched side increased by approximately 5 meters, while on the trenched side only increased a distance of 2.5 meters. Terraces on Miami Corporation land also had significant difference between the un-trenched and trenched sides (p=0.006), though growth from the crown of the terraces was slight and some of the terraces appeared to be deteriorating. There was no significant difference in lateral vegetation growth at any of the other terraces at any site, including three different terrace fields on the west side of Sabine NWR. However, terraces at one Sabine site, 4 years in age, had nearly as much lateral growth overall as the 13 year old terraces. Terraces with the lowest soil bulk densities and the highest percent organic material were not increasing in size, but were deteriorating. Terraces on Miami Corporation land with 12% organic material and in Rockefeller Refuges Unit 5 with 16% organic material were the only places that some terraces were in a state of deterioration after 1 year and 3 years, respectively. All other terraces had less than 5% organic material and were in various stages of lateral growth.
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