Vegetative damage caused by nutria has been documented in at least 11 Coastal Wetlands Planning Protection and Restoration Act (CWPPRA) project sites in the Barataria-Terrebonne Basins. The estimate of 80,000 acres of marsh damaged was conservative because only the worse (most obvious) can be detected from aerial surveys. The number of acres being impacted was certainly higher. Since the introduction of the Coastwide Nutria Control Program, the number of impacted acres has dropped to 23,141 acres. When vegetation is removed from the surface of the marsh, as a result of over grazing by nutria, the very fragile organic soils are exposed to erosion through tidal action. If damaged areas do not revegetate quickly, they will become open water as tidal scour removes soil and thus lowers elevation. Frequently the plant's root systems are also damaged, making recovery through vegetative regeneration very slow.

Date	Total # of Damage Sites	Total # of Damage Acres *
1998	170	23,960
1999	150	27,356
2000	132	25,939
2001	124	22,139

 

Date	Total # of Damage Sites	Total # of Damage Acres *
2002	94	21,185
2003	84	21,888
2004	69	16,906
2005	49	14,260
2006	31	12,315
2007	23	9,244
2008	23	6,171

* When extrapolated to a coastwide estimate, the acres impacted over these years ranges from 102,585 to 23,141 acres (damaged acres x 3.75). The 3.75 multiplication factor comes from the area actually surveyed along transect lines (0.5 miles) and the distance between transect lines (1.87 miles).

Click below on images to see wetland damage caused by nutria.