The list of ecoregions in Louisiana are listings of terrestrial ecoregions (see also, ecosystem) in the United States' State of Louisiana, as defined separately by the United States Environmental Protection Agency (USEPA), and the World Wildlife Fund. Louisiana's ecology is in a land area of 51,840 square miles (134,264 km2); the state is 379 miles (610 km) long and 130 miles (231 km) wide and is located between latitude: 28° 56′ N to 33° 01′ N, and longitude: 88° 49′ W to 94° 03′ W, with a humid subtropical climate (Köppen climate classification Cfa).
The USEPA's ecoregions are identified through the analysis of the spatial patterns and the composition of biotic and abiotic characteristics that affect or reflect differences in ecosystem quality and integrity. These characteristics include geology, physiography, vegetation, climate, soils, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another regardless of ecoregion hierarchical level.[1]
Louisiana contains barrier islands and coastal lowlands, large river floodplains, rolling and hilly coastal plains with evergreen and deciduous forests, and a variety of aquatic habitats. There are 6 level III ecoregions and 28 level IV ecoregions, and most of these continue into ecologically similar parts of adjacent states.
WWF ecoregions are defined as "relatively large units of land or water containing a distinct assemblage of natural communities sharing a large majority of species, dynamics, and environmental conditions.... Ecoregions represent the original distribution of distinct assemblages of species and communities."[2]
| Nearctic | Temperate broadleaf and mixed forests | Mississippi lowland forests | |
| Nearctic | Temperate broadleaf and mixed forests | Southeastern mixed forests | |
| Nearctic | Temperate coniferous forests | Piney Woods forests | |
| Nearctic | Temperate coniferous forests | Southeastern conifer forests | |
| Nearctic | Tropical and subtropical grasslands, savannas, and shrublands | Western Gulf coastal grasslands |
Landforms of the Louisiana Coastal Plain