Projects

Ruppia maritima restoration using seedlings in Bayou Cumbest, Grand Bay National Estuarine Research Reserve, Mississippi

Abstract

Grand Bay NERR strives to advance coastal science and improve the management of representative estuarine ecosystems along the Mississippi Coast. According to our ongoing seasonal surveys, Hurricane Katrina in 2005 resulted in loss of R.maritima (approximately 5 acres) in Bayou Cumbest due to physical disturbance and toxic pollutants released from damaged camps and residential properties. Because of the nearly 100% dependency on asexual reproduction by R. maritima in the bayou, and the lack of appropriate water currents to facilitate fragment dispersal, restoration in the bayou requires human assistance in the revegetation process. R. maritima was the only SAV species that occurred in the brackish marsh and bayous prior to the hurricane and the salinities in the area.

Estuarine Ruppia maritima produces an enormous number of seeds (several thousands to tens of thousands seeds per square meter) that are protected by sturdy seed coats. Desiccated seeds can stay viable for an extended period of up to several years, and be broadcast into the field in a large amount in a short period of time. On the other hand, R. maritima that occurs in low salinity streams, marsh ponds, and bayous rarely flowers and sets seeds. Although not tested on local populations, the difference in reproductive strategy between the estuarine and bayou populations within Grand Bay NERR probably resulted from plastic ecological adaptation of the same species to the varying habitats. Therefore, we propose to revegetate the bayou using seeds that are collected from the estuarine R. maritima beds of Grand Bay NERR

Objectives

Through this Program Development project, we intend to field-test the survival of laboratory-grown Ruppia maritima L. seedlings in Bayou Cumbest of Grand Bay National Estuarine Research Reserve (NERR), MS.

  • To determine the effectiveness of seeds/seedling transplanting methods for restoring R. maritima in bayous, streams, and brackish marshes.
  • To restore SAV beds in Bayou Cumbest that have been lost since the 2005 hurricanes through seed broadcast and seedling transplanting.

Methodology

Seeds of Ruppia maritima will be hand-collected in natural beds of Grand Bay NERR at maturation (April-May). The seeds will be treated in the laboratory either to induce a dormancy with a minimum loss of viability or to produce seedlings. Peat pots and biodegradable mats (i.e. burlap) will be used to transplant the seeds/seedlings to re-vegetate Bayou Cumbest where the previous R. maritima beds have been lost after hurricanes Katrina and Rita. After transplanting, we will conduct monitoring for the plant establishment, growth, and expansion. The success of seedling growth in the field will be determined in selected test plots; and the germination rates will be compared with those obtained from laboratory studies. The “no treatment” areas will also be monitored to rule out the possibility that SAV sprouted from the seed bank. The cost and time to restore SAV habitat area will be calculated for each transplanting technique.