Home » Regions » North America » Eastern Temperate Forests » Southeastern USA Plains » Mississippi Valley Loess Plains

Mississippi Valley Loess Plains

Page contents

To check where a specific point lies, you can look it up in our Ecoregion Locator.

Map Legend & Subregion List

This list will help you navigate the regions in case you have problems with viewing or clicking the interactive map above.

NameColor on MapEPA Code*
Bluff Hills74a
Loess Plains74b
Southern Rolling Plains74c
Baton Rouge Terrace74d

* This code refers to the US EPA's Level 4 ecoregion codes for the continental U.S., see here.

About the Mississippi Valley Loess Plains

The Mississippi Valley Loess Plains is a narrow region stretching north-south along the Missippi river, not in the river's floodplain itself, but directly east of it. In the northernmost portion of this region, a much-more-narrow portion exists on the west side as well. This region is named for and characterized by Loess, a fine sediment that accumulated from wind-blown dust.

The topography here is more hilly and irregular than that of the Missippii alluvial plain, with gently rolling hills, and some bluffs along the river. The soils here are deep, fine-textured, and easily erodible. The topography is steepest in the west, and tends to become flatter to the east.

The climate is humid and subtropical, with high total rainfall. Temperatures are warmer to the south, with the most prononuced differences being that the south has warmer average high temperatures in winter (as much as 17°F / 9.5°C difference) with less variation of summer highs or average winter lows and almost no difference in average winter lows. There is also more continental character as one moves north, with greater changes of weather both from day-to-day and year-to-year. Although precipitation is mostly equally distributed year-round, there is a significant season with less rainfall, with the minimum usually reached in August or September. The northernmost end of this region also has a weak, bimodal precipitation pattern with a second dry season in January-February and peak rainfall in May and December.

Original forest cover here consisted of mixed mesophytic forest and southern mesophytic forest on the bluffs in the west, with upland areas to the east dominated by oak, hickory, loblolly pine, and shortleaf pine.

There is significant agriculture in this region, more in the northern portion located in Kentucky and Tennessee. In Mississippi, this region is markedly less developed for agriculture than the region to the west, with only scattered cropland interspersed with forests.

Memphis, TN is the largest city in this region, followed by Jackson, MS. Besides these cities, most of the region is sparsely-populated.

This region is bordered to the west and south by the Mississippi Alluvial Plain, which also surrounds a narrow piece of this region further west. To the east is is bordered along its length by the Southeastern Plains. At its very southern end, it shares a small border to the east with the Southern Coastal Plain. At its northernmost end, it borders the Interior Plateau to the east, and the Interior River Valleys and Hills to the north.

References

1. Wiken, E., Griffith, G. "North American Terrestrial Ecoregions - Level III", Commission for Environmental Cooperation, (2011) Web.