Restoration amidst logging pressure in the degraded Maurepas swamp, Louisiana: a Mississippi River diversion feasibility study.
Shaffer, Gary*,1, Perkins, Thais1, Hoeppner, Susanne2, Zoller, Jason1, Day, John 2, 1 Southeastern Louisiana University, Hammond, Louisiana, USA2 Louisiana State University, Baton Rouge, LA, USA
ABSTRACT- The swamp forests surrounding Lake Maurepas, located in southeastern Louisiana, have been in a state of decline for at least five decades. A diversion of the Mississippi River into these swamps has been designed to bring nutrients, sediments and freshwater to the system, as it did historically. To evaluate the potential effects of the diversion and to estimate the assimilative capacity of the swamp, measures of the annual primary production of trees and the herbaceous undercover, soil subsidence levels, and various soil and water characteristics were taken in replicate at 20 study sites representing four habitat types. Despite several years of average rainfall, forest production decreased from 2000-2003, perhaps a carry-over effect of the 1998-2000 drought. Lower forest production was accompanied by higher herbaceous production, presumably attributable to increased light levels. As a response to logging pressure, a geographic information system (GIS) was built to estimate the proportion of non-sustainable swamp in the Maurepas, and a team of scientists was assembled to develop recommendations for logging in swamps of coastal Louisiana. Using the permanent sites as training areas for constructing the GIS, we estimate that 25% of the swamp has already converted to marsh and open water, 55% is relic (non-sustainable) swamp, and 20% is naturally or artificially sustainable. At present, it appears that a diversion of approximately 60 cubic meters per second would greatly enhance swamp production and forest sustainability without triggering algae blooms in Lake Maurepas. The proposed diversion has now been funded by the Louisiana Coastal Area program.
Key words: swamp restoration, mississippi river diversion, logging, coastal Louisiana
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