Estimates for acreage changes from the mid-1970's to the mid-1980's were developed for 13 wetland and deepwater habitat categories within the Southeast Region (Fig. 1). Data tables for the region are presented in Appendix B.

REGIONAL STATUS

There were an estimated 51.2 million acres of wetlands in the Southeast Region in the mid-1970's. An estimated 48.9 million acres remained by the mid-1980's. The average annual net loss for the period was 259,000 acres. In the mid-1980's, 91 percent of the region's wetlands (44.6 million acres) were palustrine (freshwater). The remaining 9 percent (4.3 million acres) were estuarine wetlands (Fig. 3).

Figure 3.
Wetlands of the Southeast

The estuarine intertidal emergent category accounted for 73 percent of estuarine wetlands. Another 16 percent were estuarine forested/ shrub, principally mangrove-dominated habitats. Approximately 11 percent of all estuarine wetlands were nonvegetated, e.g. saltflats, mudflats and sandbars (Fig.4).

Figure 4.
Estuarine wetlands of the Southeast

Palustrine forested wetlands represented 74 percent of all freshwater wetlands in the region. Freshwater emergent wetlands made up 13 percent. Wetlands dominated by shrubs comprised 10 percent. Palustrine unconsolidated bottom (freshwater ponds) were 3 percent of the total (Fig.5).

Figure 5.
Palustrine wetlands of the Southeast

Wetlands covered approximately 16 percent of the Southeast landscape in the mid-1980's. Deepwater habitats occupied an additional 5 percent of the area for a combined total of 21 percent of the region's acreage (Fig. 6).

Figure 6.
Wetlands, deepwater habitats and uplands of the Southeast

Wetlands are present in every physical subdivision of the Southeast. The highest wetland density occurred in the combined area of the Gulf-Atlantic Coastal Flats and Coastal Zone, where wetlands covered 31 percent of the landscape. Although these two areas represent less than a fourth of the region, nearly half of the region's wetlands occur there. More than three-quarters of the deepwater habitat acreage in the Southeast was estimated within these physical subdivisions, primarily due to extensive estuarine subtidal habitats in the Coastal Zone.

REGIONAL TRENDS

Estuarine Wetlands

Estuarine wetlands declined by 1.2 percent, a net loss of 50,000 acres. This does not include all of the coastal wetland losses during the study period because most coastal areas also contain extensive palustrine wetlands that may have experienced losses. Therefore, the overall loss of coastal wetlands in states like Louisiana cannot be derived exclusively from losses of estuarine wetlands.

An increase in estuarine intertidal nonvegetated habitats partially masked a 60,000-acre decrease in estuarine intertidal emergent wetlands (saltmarshes). Nearly all saltmarsh loss and most of the increase in nonvegetated habitats occurred in Louisiana. There was little change in mangrove-dominated habitats. Estuarine subtidal (bay bottoms) increased by 27,000 acres; virtually all the increase was the result of saltmarsh loss in Louisiana. Except for coastal Louisiana, the acreage of estuarine wetlands and deepwater habitats remained stable from the mid-1970's to mid-1980's.

Palustrine Wetlands

Freshwater wetlands declined by 4.9 percent, a net loss of 2.3 million acres, from the mid-1970's base. Palustrine forested wetlands suffered large losses. All other freshwater categories showed slight net increases from conversions of palustrine forested wetlands to those categories (Fig. 7).

Figure 7.
Palustrine wetland gains and losses in the Southeast

Approximately 3.1 million acres of palustrine forested wetlands (9 percent) were lost or converted. Nearly two-thirds of this decrease was actual wetland loss to agriculture and the "other" (i.e. forest, range land and barren land) upland category. Most of the remaining decrease resulted from conversions to other wetland types, particularly palustrine scrub/shrub and emergent wetlands (Fig. 8).

Figure 8.
Fate of palustrine forested wetlands: Losses and conversions

More than two-thirds of the palustrine forested wetland loss took place in the Lower Mississippi Alluvial Plain (Louisiana, Mississippi and Arkansas) and the Gulf-Atlantic Coastal Flats, especially in North Carolina. Nearly 900,000 acres were lost to agriculture in the Lower Mississippi Alluvial Plain. Within the Gulf-Atlantic Coastal Flats of North Carolina, 887,000 acres were lost, nearly all of which went to the "other" category. There were no identifiable gains to palustrine forested wetlands within the region.

Palustrine emergent wetlands showed a net increase, with losses offset by conversion (i.e. cleared but otherwise unaltered) of palustrine forested to the palustrine emergent category (Table 5).

Table 5.
States with large conversions from palustrine forested to palustrine emergent wetlands.

There were large losses of palustrine emergent wetlands at specific locations. For example, nearly 108,000 acres were lost to agriculture in Florida. Regionwide, agriculture claimed 209,000 acres of palustrine emergent wetlands. More than 13,000 acres of palustrine emergent wetlands were lost to urban development -- mainly in Florida -- and 89,000 acres went to the category "other," mostly in North Carolina.

Palustrine scrub/shrub wetlands showed no measurable net change. As with palustrine emergent wetlands, scrub/shrub losses were offset by conversions of palustrine forested wetlands.

More than 719,000 acres of palustrine forested wetlands were converted to scrub/shrub wetlands. A third of this conversion took place in Georgia. More than 181,000 acres of palustrine emergent wetlands succeeded to scrub/shrub wetlands -- more than half of this in Florida.

During the study period, 112,000 acres of palustrine scrub/shrub wetlands were lost to agriculture. Florida accounted for approximately half of this loss with the remaining losses spread among North Carolina, Mississippi, Georgia and Arkansas. About 272,000 acres of scrub/shrub wetlands were lost to "other," predominantly in North Carolina.

Palustrine nonvegetated wetlands, e.g. mudflats, beaches, sandbars and small water bodies, increased by 43 percent, or 400,000 acres. Water bodies such as farm ponds, mine pits, golf course and residential ponds accounted for most of the increase in nonvegetated freshwater wetlands. More than half of the increase occurred in Arkansas. Most of the increases came from upland areas, predominantly from the "other" category. In general, these wetland increases did not affect the acreage totals of vegetated wetlands or agriculture.

Deepwater Habitats

There was a net increase of 199,000 acres of lakes (lacustrine habitat) during the study period. Most of the increased acreage came from the upland categories of agriculture and "other," with some increases from palustrine scrub/shrub and forested wetlands.

STATE ANALYSES

The number of sample plots within each state was based on the anticipated density and variability of the wetlands (see Survey Methods). The reliability and extent of the state-specific estimates varies. Precise estimates were possible for states with large sample sizes (Louisiana and Florida), while estimates were much less reliable for states with very small sample sizes (Kentucky and Tennessee). State trend information is summarized in Table 6. Wetland acreage estimates, the percent of land surface occupied by wetland and net wetland losses for each state are summarized in Figure 9.

Table 6.
Wetland trends for the Southeast states, mid-1970's to mid-1980's.

Figure 9.
Wetland acreages, percentage of state landscapes and net losses, by state, mid-1970's to mid-1980's

Alabama

Wetlands covered approximately 2.7 million acres or nearly 8 percent of Alabama. Palustrine forested wetlands made up over 80 percent (2.2 million acres) of the total. The net loss of wetlands was estimated to be 42,000 acres. The principal cause of the net wetland loss was agricultural development.

Arkansas

Arkansas contained nearly 3.6 million acres of wetlands, more than 10 percent of the state's land surface. Approximately 2.8 million acres were palustrine forested, the majority of which were located in the Lower Mississippi Alluvial Plain. Although a reliable estimate of net wetlands change could not be determined, there was an estimated forested wetland decrease of 210,000 acres.

Florida

Florida contained more than 11.0 million acres of wetlands, approximately 30 percent of the state. Among the southeastern states, Florida had the greatest wetland acreage and density. Palustrine (freshwater) wetlands predominated, covering more than 9.6 million acres.

Palustrine forested wetlands covered 5.5 million acres, 50 percent of the state's wetland total. Palustrine emergent wetlands covered 2.9 million acres (26 percent). Palustrine scrub/shrub wetlands covered 1.2 million acres, or about 10 percent of the state's wetland total. Florida showed a net wetland loss of 260,000 acres, mainly from the destruction of palustrine wetlands. Two-thirds of the loss of palustrine wetlands was attributable to agricultural development, with the rest split evenly between urban development and "other" land use.

Estuarine wetlands, most of which were saltmarsh and mangroves, totaled 1.4 million acres. Some losses of estuarine vegetated wetlands were due to urbanization. A precise estuarine wetland loss estimate could not be determined.

Excellent statistical reliability was achieved in a number of other categories due to the large sample size. Complete results of the Florida analysis are in Frayer and Hefner (1991).

Forested wetland conversion in Florida
PALUSTRINE FORESTED TO PALUSTRINE EMERGENT
JOHN HEFNER

Georgia

Georgia followed Florida and Louisiana with a total wetland area of 7.7 million acres, covering 20 percent of the state's landscape. This total included nearly 367,000 acres of estuarine wetlands and 7.3 million acres of palustrine wetlands. The state's net wetland loss was estimated at approximately 78,000 acres.

Palustrine forested was the predominant wetland type, approximately 6.1 million acres. Nearly 500,000 acres of palustrine forested wetlands were converted (i.e. cleared but otherwise unaltered), with virtually the entire change to palustrine scrub/shrub or emergent wetland.

Kentucky

The estimated total wetland acreage was 388,000 acres, covering about 1 percent of the land surface. The predominant type was palustrine forested wetland. A statistically reliable estimate of wetland change could not be determined.

Cumberland Island, Georgia
MARINE INTERTIDAL
© GEORGE GENTRY

Louisiana

Louisiana was second to Florida with a total wetland area of 8.8 million acres, 28 percent of the state's surface area. Estuarine wetlands, consisting mainly of saltmarshes and some mangroves, totaled 1.9 million acres. Palustrine wetlands totaled 6.9 million acres, of which 4.9 million acres were forested and 1.5 million acres were emergent.

The net loss for all Louisiana wetland types was 518,000 acres. Approximately 57,000 acres of estuarine vegetated wetlands were changed to other habitats. Nearly three-quarters of the estuarine wetland change was the conversion of vegetated wetland to deepwater habitat, i.e. from marsh to open water. Palustrine forested wetlands declined dramatically, with net losses and conversions of 628,000 acres. Most palustrine forested wetland losses in Louisiana took place in the Lower Mississippi Alluvial Plain and were directly attributable to agricultural development.

Mississippi

Mississippi had 4.4 million acres of wetlands, about 14 percent of the state's land surface. Of the total wetland area, 3.7 million acres were palustrine forested. A net loss of 209,000 acres of wetlands was estimated. More than 365,000 acres of palustrine forested wetlands were lost or converted to other wetland types. Over half of the change can be attributed to agricultural development in the Lower Mississippi Alluvial Plain.

North Carolina

North Carolina had 5.0 million acres of wetlands, 15 percent of the landscape. This total included 154,000 acres of estuarine emergent wetlands. Palustrine wetlands held 4.9 million acres, of which 3.4 million acres were forested, 1.3 million acres were scrub/shrub, approximately 119,000 acres were emergent wetlands, and 81,000 acres were unconsolidated bottom (ponds).

North Carolina stood out among all southeastern states with the highest acreage of net wetland loss. An estimated 1.2 million acres of wetlands were lost to the "other" (forest, range land and barren land) non-wetland category. Nearly all the losses were from palustrine forested and palustrine scrub/shrub wetlands, and were concentrated in the Gulf-Atlantic Coastal Flats.

South Carolina

South Carolina had 4.7 million acres of wetlands, nearly 24 percent of the state. This acreage included 418,000 acres of estuarine emergent wetlands (saltmarsh). Palustrine wetlands held 3.6 million acres of forested wetlands, 369,000 acres of scrub/shrub wetlands, and 218,000 acres of palustrine emergent wetlands.

The state's net loss of wetlands during the study period was estimated at 61,000 acres. The greatest acreage change occurred in the palustrine forested wetland category. About one-third of the 125,000 acres of forested wetlands altered was lost to non-wetland categories.

Tennessee

There were an estimated 632,000 acres of wetlands, covering about 2 percent of the state. Most of this total was palustrine forested wetlands. The net loss of wetlands was estimated at 25,000 acres.

Cardinal flower in Lutcher Moore Swamp, Louisiana
PALUSTRINE FORESTED
© NANCY WEBB