CHAPTER III: MISSISSIPPI’S ECOLOGICAL FRAMEWORK-ECOREGIONS OF MISSISSIPPI 73
surrounding areas due to the fertile topsoil and abundant moisture. In many cases, the bluffs provide
habitat for plant species that are rare or absent from other parts of the Coastal Plain. In addition, the
bluffs constituted a major refugium for mesophytic plant species, now generally more common to the
north, during the last glaciation.
Blackland Prairies occur in two discrete areas of the ecoregion: the Jackson Prairie and the Black Belt
(see Northeast Prairie subtype in this CWCS). These areas are among the distinct topographic regions in
the state of Mississippi. At their closest point, 65 miles separate the formations supporting the two
prairie types. The Black Belt is the larger of the two regions, stretching approximately 300 miles across
Mississippi and into adjacent parts of central Alabama. This region, generally 25-30 miles wide, derives
its name from the nearly black, rich topsoil that developed over Selma Chalk. Both areas have typically
calcareous soils and were formerly occupied by natural grasslands and associated vegetation.
The broad forest cover composition also differs between parts of the region. While the percentage of
total area occupied by deciduous forests is relatively evenly distributed across the region, mixed and
evergreen forests (each generally including a component of pine species) are much less common overall
in both the Black Belt and the North Unit (North of the Mississippi-Tennessee state line). The reasons
for this pattern are most obvious in the case of the North Unit, most of which lies outside the natural
range of the southern pine species (loblolly, shortleaf, longleaf) commonly encountered this ecoregion.
The lack of evergreen forests in the Black Belt is more complex, but is likely due to the poor suitability
of the predominantly calcareous soils for pine growth.
The composition of the ecoregion's forests is also changing. Vast acreages of the region are being
converted to pine plantations, in many cases at the expense of either existing deciduous or mixed forests,
constituting one of the most consequential forestry developments in the region in the last four decades.
The following habitat types described in Chapter IV of this CWCS can be found in the UEGCP
ecoregion:
Dry-Mesic Upland Forests/Woodlands
Agriculture Fields, Hay and Pasture Lands, Old Fields, Prairies,
Cedar Glades and Pine Plantations
Mesic Upland Forests
Bottomland Hardwood Forests
Riverfront Forests/Herblands/Sandbars
Inland Freshwater Marshes
Swamp Forests
Lacustrine Communities
Streams