Status and Trends

of Wetlands

IN THE Coastal Watersheds of the Eastern United States

1998 to 2004
Conversion Table

United States Customary to Metric

United States Units Metric Units

inches (in.) x 25.40 millimeters (mm)

inches (in.) x 2.54 centimeters (cm)

feet (ft) x 0.30 meters (m)

miles (mi) x 1.61 kilometers (km)

nautical miles (nmi) x 1.85 kilometers (km)

square feet (ft2) x 0.09 square meters (m2)

square miles (mi2) x 2.59 square kilometers (km2)

acres (A) x 0.40 hectares (ha)

Farenheit degrees (F) 0.5556 (F - 32) Celsius degrees (C)

Metric to United States Customary

Metric Units United States Units

millimeters (mm) x 0.04 inches (in.)

centimeters (cm) x 0.39 inches (in.)

meters (m) x 3.28 feet (ft)

kilometers (km) x 0.62 miles (mi)

kilometers (km) x 0.54 nautical miles (nmi)

square meters (m2) x 10.76 square feet (ft2)

square kilometers (km2) x 0.39 square miles (mi2)

hectares (ha) x 2.47 acres (A)

Celsius degrees (C) 1.8(C) + 32 Farenheit degrees (F)
Statu s and T rend s of Wetland s 1

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

and

U.S. Department of the Interior

Fish and Wildlife Service

Status and Trends

of Wetlands

IN THE Coastal Watersheds of the Eastern United States

1998 to 2004
This report should be cited as:

Stedman, S. and T.E. Dahl. 2008. Status and trends of wetlands in the coastal watersheds of the Eastern United States 1998 

to 2004. National Oceanic and Atmospheric Administration, National Marine Fisheries Service and U.S. Department of the 

Interior, Fish and Wildlife Service. (32 pages)

General Disclaimer

The use of trade, product, industry, or firm names or products in this report is for informative

purposes only and does not constitute an endorsement by any agency of the U.S. Government.

Status and Trends of Wetlands 

Coastal Watersheds of the Eastern United States

1998 to 2004

Susan-Marie Stedman

NOAA, National Marine Fisheries Service

and

Thomas E. Dahl

U.S. Fish and Wildlife Service

Acknowledgments

The authors wish to thank numerous agencies and individuals who provided input to this report. Particularly helpful 

were interagency briefings sponsored by the National Oceanic and Atmospheric Administration’s (NOAA) National Marine 

Fisheries Service (NMFS) and the U.S. Environmental Protection Agency (EPA), Office of Wetlands, Oceans, and Watersheds, 

and attended by senior staff from the Council on Environmental Quality, Office of Management and Budget, U.S. Army Corps 

of Engineers, U.S. Department of Agriculture, NOAA, EPA, and U.S. Fish and Wildlife Service (FWS). These briefings helped 

formulate the context and presentation of the report findings and set the stage for additional collaborative efforts.

In addition, expert subject matter peer review was provided by the following technical specialists: Michael Scozzafava, 

Wetlands Division, EPA; William B. Ainslie, Wetlands Regulatory Section, EPA Region IV; Jennifer A. Wheeler, Waterbird 

Coordinator, Division of Migratory Bird Management, FWS; Martin Kodis, Chief, Branch of Resource and Mapping Support, 

Division of Habitat and Resource Conservation, FWS; FWS Regional Wetlands Coordinators Bill Kirchner, Brian Huberty, John 

Swords, Ralph Tiner, Kevin Bon, and Jerry Tande; Gary Whelan, Michigan Department of Natural Resources; and Tom Bigford, 

NMFS Office of Habitat Conservation.
Statu

s and T rends of Wetlands

3

CONTENTS

Executive Summary5

Introduction6

Coastal Wetlands7

Current Study Area, Procedures, and Objectives 10

Definitions of Habitat Categories within Coastal Watersheds 12

Results: Status, Distribution, and Trends 14

Summary and Conclusions 26

References Cited 27

Appendix: Definitions of Habitat Categories 29
4 Statu s and T rend s of Wetland s

List of Figures

Figure 1. Coastal watersheds of the Atlantic, Gulf of Mexico, and Great Lakes 10

Figure 2. Wetland area of the coastal watersheds of the Atlantic, Gulf of Mexico, 

and Great Lakes 14

Figure 3. Wetland types in the coastal watersheds of the Atlantic, Gulf of Mexico, 

and Great Lakes, 2004 14

Figure 4. Wetland density in the coastal watersheds of the Atlantic and 

Gulf of Mexico, 2004 15

Figure 5. Wetland gains and losses for the Atlantic, Gulf of Mexico, and 

Great Lakes coastal watersheds, 1998 to 2004 17

Figure 6. Attribution of loss or conversion of saltwater wetlands in the 

coastal watersheds of the Atlantic and Gulf of Mexico, 1998 to 2004 20

Figure 7. Areas of greatest coastal wetland loss in the Gulf of Mexico 24

Figure 8. Attribution of loss or conversion of freshwater wetlands in the coastal

watersheds of the Atlantic, Gulf of Mexico, and Great Lakes, 1998 to 2004 24

Figure 9. Net gains and losses of coastal wetlands in the Great Lakes 

coastal watersheds, 1998 to 2004 24

Figure 10. St. Vincent Island restoration site, Florida, post-restoration 25

List of Tables

Table 1. Previous studies of coastal wetland status and trends 8

Table 2. Area of coastal watersheds in this study 11

Table 3. Wetland, deepwater, and upland categories used in this study 13

Table 4. Estimated change in wetland area for selected wetland categories 

for coastal watersheds of the Atlantic, Gulf of Mexico, and Great Lakes, 

1998 to 2004 16

Table 5. Estimated changes to saltwater (estuarine and marine) wetlands 

in the coastal watersheds of the Atlantic and Gulf of Mexico coasts, 

1998 to 2004 19

Table 6. Estimated freshwater wetland acreage for coastal watersheds 

of the Atlantic, Gulf of Mexico, and Great Lakes as compared to the 

conterminous United States, 2004 21

Table 7. Estimated changes to freshwater wetlands in the Coastal Watersheds 

of the Atlantic, Gulf of Mexico, and Great Lakes, 1998 to 2004 22 
Statu s and T rend s of Wetland s 5

EXECUTIVE SUMMARY

he National Oceanic and Atmospheric Administration’s National Marine Fisheries Service, in 

cooperation with the U.S. Fish and Wildlife Service, analyzed the status and recent trends of 

wetland acreage in the coastal watersheds of the United States adjacent to the Atlantic Ocean, 

Gulf of Mexico, and Great Lakes. Sample plots were analyzed using digital high-resolution Timagery to identify wetlands and land use changes observed between 1998 and 2004. 

Results indicate that there were an estimated 39.8 

million acres (16.1 million ha) of wetlands in these 

coastal watersheds in 2004. This represented 38 

percent of the estimated total wetland acreage of 

107.7 million acres (43.6 million ha) found in the 

conterminous United States. 

Coastal watersheds experienced a net loss in wetland 

area. There was an estimated wetland loss of 361,000 

acres (146,200 ha) in the coastal watersheds of the 

eastern U.S. between 1998 and 2004. This equated 

to an average annual net loss of about 59,000 acres 

(24,300 ha) over the 6-year period of this study. Gulf 

of Mexico coastal watersheds exhibited substantial 

losses in freshwater wetlands. This rate of loss was 

6 times higher than the rate of freshwater vegetated 

wetlands losses in the Atlantic coastal watersheds. The 

estimated losses for all wetland types in the Gulf of 

Mexico were 25 times higher than those estimates for 

the Atlantic over the course of this study. There was 

a net gain of an estimated 24,650 acres (10,000 ha) 

in the Great Lakes coastal watersheds over the same 

period of time.

In the time period encompassed by this study, trends 

suggested the country as a whole was gaining wetlands. 

From 1998 to 2004, wetland gains in the conterminous 

United States were estimated to have been 32,000 

acres (12,960 ha) annually. The fact that coastal 

watersheds were losing wetlands despite the national 

trend of net gains points to the need for more research 

on the natural and human forces behind these trends 

and to an expanded effort on conservation of wetlands 

in these coastal areas. This point was highlighted in a 

2008 report on wetland conservation by the Council on 

Environmental Quality. 
6 Statu s and T rend s of Wetland s

INTRODUCTION

his report is the result of a cooperative effort between the National Oceanic and Atmospheric 

Administration’s (NOAA) National Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife 

Service (FWS). The efforts to monitor coastal wetland status and trends described in this report 

have been enhanced by the multi-agency involvement in the study’s design, data collection, Tverification, and peer review of the findings.

NMFS’ mission is to conserve, protect, and manage living 

marine resources in a way that ensures their continuation 

as functioning components of marine ecosystems, affords 

economic opportunities, and enhances the quality of 

life for the American public. Coastal wetlands provide 

valuable habitat for the vast majority of commercially 

harvested and recreational marine species. NOAA has 

produced regional and localized studies tracking land use 

and wetland change in coastal areas, as well as studies 

on the ecological and economic importance of coastal 

wetlands (NOAA 2005, 2008). The NMFS Habitat Program 

places special emphasis on the conservation of wetlands 

as essential fish habitat for harvested species and vital 

habitat for other species of ecological significance.

The mission of FWS is to conserve, protect, and enhance 

fish and wildlife and their habitats for the continuing 

benefit of the American people. The importance of 

wetlands as fish and wildlife habitat has always been 

the primary focus of FWS’ wetland activities. FWS 

communicates information essential for public awareness 

and understanding of the importance of fish and wildlife 

resources and changes in environmental conditions that 

can affect the welfare of Americans. To this end, FWS 

maintains an active role in monitoring wetland habitats 

of the nation. NMFS and FWS have collaborated in a 

number of efforts that produce information on coastal 

habitats for fish and wildlife species. NOAA provided 

financial and logistical support for the previous two 

iterations of the Wetland Status and Trends report 

published in 2001 and 2006.

Because wetlands are often viewed as transitional 

habitats between water and dry land, wetland abundance, 

type, and quality are directly reflected in the health and 

abundance of many fish and wildlife species. Coastal 

wetland ecosystems include the wetlands immediately 

along the sea coast or Great Lakes and along the rivers 

and bays that make up the coastal drainage area. Coastal 

wetlands support life on land and in the sea by providing 

nutrients, food, and places for plants and animals to 

reproduce and grow.

The Emergency Wetlands Resources Act of 1986 (Public 

Law 99-645) was enacted to promote the conservation 

of our nation’s wetlands. The Act requires FWS to 

conduct wetland status and trend studies of the nation’s 

wetlands at periodic intervals. This is accomplished using 

a stratified, random sampling design where sample plots 

are examined with the use of remotely sensed imagery, 

in combination with field work, to determine wetland 

change. 

The most recent national study detailed the status and 

trends of wetlands from 1998 to 2004 (Dahl 2006). 

Wetland trends data collected as part of that effort also 

provided statistical estimates of wetland status and 

trends for the coastal watersheds contained in this report. 

This report analyzed 2,265 sample plots using digital 

high-resolution imagery to identify wetlands, deepwater 

habitats, and uplands. Changes in areal extent or type of 

wetland observed in the sample plots between 1998 and 

2004 were recorded. Field verification was completed for 

824 of the sample plots (36 percent). 

This report presents the latest status information on 

coastal wetland resources and provides estimates of losses 

or gains that occurred in the coastal watersheds between 

1998 and 2004. These data were analyzed beyond the 

national data set and provide new information about 

wetland trends specific to the coastal watersheds of the 

Atlantic, Gulf of Mexico, and Great Lakes coasts It should 

be noted that the estimates of wetland area were made 

prior to hurricanes Katrina and Rita in 2005. 
Statu s and T rend s of Wetland s 7

Coastal Wetlands

Coastal wetlands occur along the shores of the United States, with the largest expanses along the 

Gulf of Mexico and southern Atlantic coasts. Coastal wetland ecosystems are integrated by the 

water that flows through them, which connects the wetlands immediately along the ocean or Great 

Lakes with those of the rivers and floodplains upstream. Coastal wetland types are as diverse as salt 

marshes, bottomland hardwood swamps, fresh marshes, mangrove swamps, and shrub depressions 

known in the southeast United States as “pocosins.” The definitive factor in coastal wetlands is 

the effect of tides on the watershed as a whole. For this reason, coastal wetlands can be described as all wetlands 

below head of tide in watersheds that drain to the Atlantic Ocean, Gulf of Mexico, or Pacific Ocean, as well as 

wetlands that drain directly to one of the Great Lakes. The target population of wetlands included in this study was 

all wetlands in the coastal watersheds of the Atlantic, Gulf of Mexico, and Great Lakes.1

Coastal wetlands, like inland wetlands, are among the 

most productive ecosystems on Earth. The bidirectional 

water movement caused by tides in marine coastal 

wetlands can augment productivity to even higher 

levels in what is called a “tidal subsidy.” The close 

connection between coastal wetlands and large water 

bodies provides extensive coastal transport mechanisms 

driven by littoral drift and larger ocean currents such 

as the Gulf Stream, and the large interlake circulation 

cells exhibited by each of the Great Lakes can magnify 

the role coastal wetlands play on marine ecosystems. 

More than half of commercially harvested fish in the 

United States depend on estuaries and nearby coastal 

waters at some stage in their life cycle (Lellis-Dibble et 

al. 2008). Coastal habitats provide spawning grounds, 

nurseries, shelter, and food for finfish, shellfish, birds, 

and other wildlife (NRC 1997). The abundance and 

health of adult stocks of commercially harvested 

shrimp, blue crabs, oysters, and other species are 

directly related to wetland quality and quantity (Turner 

and Boesch 1988; Stedman and Hanson 2000). The 

nation’s coastal resources also provide resting, feeding, 

and breeding habitat for 85 percent of waterfowl and 

other migratory birds (EPA 2005), and nearly 45 percent 

of the nation’s endangered and threatened species are 

dependent on coastal habitats (FWS 1995). Wetlands 

help improve surface water quality by filtering, storing, 

and detoxifying residential, agricultural, and urban 

wastes, and can buffer coastal areas against storm 

and wave damage and help stabilize shorelines. The 

economic value of coastal habitats is likely to be in the 

hundreds of billions of dollars, if not more (Pendleton 

2008).

Because of their close proximity to terrestrial systems, 

coastal wetlands are vulnerable to land development, 

pollutant discharges, and other human activities. 

Coastal wetland losses and degradation can be directly 

traced to population pressures and other humaninduced changes occurring along the coast. Expanding 

populations place pressures on existing natural 

resources, particularly wetlands, which are vulnerable 

to changes in water flow, pollution, and habitat 

fragmentation. Human populations in coastal areas 

have increased steadily since 1970 (U.S. Commission on 

Ocean Policy 2004). Currently over half the population 

of the United States lives in coastal counties at 

densities about five times greater than those of noncoastal counties (Crossett et al. 2004). This trend of 

people moving to coastal areas is expected to continue 

in the coming decades. 

The results of previous studies of coastal wetland status 

and trends are summarized in Table 1. Understanding 

the status and trends of coastal wetlands is complicated, 

in part, by the lack of a universally accepted definition 

C

1 This study did not include the Pacific coast due to insufficient data.
8 Statu s and T rend s of Wetland s

of “coastal” in past studies. NOAA produced two 

estimates of coastal wetlands: one used state data for 

wetlands in coastal counties in the Atlantic, Pacific, 

and Gulf of Mexico coasts (Alexander et al. 1986), and 

the other used a statistical sampling of the existing 

FWS National Wetlands Inventory maps for wetlands 

in coastal counties and watersheds along the Atlantic, 

Pacific, and Gulf of Mexico coasts (Field et al. 1991). 

The two estimates of wetland area generated by these 

studies differed substantially, although the relative 

abundance of wetlands along the Gulf of Mexico and 

relatively small amount of wetlands on the Pacific coast 

were consistent between the two studies. The study by 

Field et al. (1991) estimated that about a third of the 

country’s wetlands were coastal.

Table 1. Previous Studies of Coastal Wetland Status and Trends 

(Atlantic, Pacific, and Gulf of Mexico only)

Study Coastal Definition Year

Area Estimate 

(acres) Time Period

Loss Estimate 

(acres/year)

Gosselink and 

Bauman 1980

non-fresh tidal wetlands 

in coastal counties

1922 9,980,000

1954 9,330,000 1922 - 1954 20,000

1974 8,405,000 1954 – 1974 46,000

Alexander et al.

1986

wetlands in coastal counties 1970s 11,000,000 NA

Tiner 1991 estuarine wetlands (excluding 

the Pacific coast)

1970s 5,532,000 1974-1983 7,900

Field et al. 1991 wetlands in coastal watersheds 1980s 27,000,000 NA

Brady and 

Flather 1994

tidal wetlands on 

non-federal lands

1982 6,713,460 1982-1987 19,323

1987 6,617,380

Brady and 

Goebel 2002

wetlands in coastal counties 

on non-federal lands

1992 22,430,000 1992-1997 24,400

1997 22,300,000

In 1994, scientists with the U.S. Department of 

Agriculture’s (USDA) Natural Resources Conservation 

Service reviewed the USDA’s Natural Resources 

Inventory (NRI) data for 1982 to 1987 and separated it 

into “coastal” and “inland” using the definitions in the 

FWS’ original wetland classification system known as 

“Circular 39” (Brady and Flather 1994). They updated 

the work in 2002 (Brady and Goebel 2002) for the 1992 

to 1997 data, including all wetlands in coastal counties 

as coastal wetlands. Like the NOAA estimates, this 

included only the Atlantic, Pacific, and Gulf of Mexico 

coasts of the coterminous United States. The 2002 

results are close to those of the second NOAA inventory 

in that approximately a third of the wetlands in the 

coterminous United States were found to be “coastal,” 

with the majority of them in the freshwater system.

Again, lack of consistency in defining the term and 

geographical extent of “coastal” has hampered 

interpretation of the above studies. Dahl (2006) 

pointed out that geographic dissimilarity, differences in 

terminology, and different time periods accounted for 

discrepancies in wetland loss estimates in Louisiana. 

Gosselink and Baumann (1980) compiled information 

from the USDA’s swamplands survey of 1922, the first 

National Wetlands Inventory in 1954 (Shaw and Fredine 
Statu s and T rend s of Wetland s 9

1956), and state surveys made in the early 1970s for 

the Atlantic, Pacific, and Gulf of Mexico coasts of the 

coterminous United States. They calculated two coastal 

wetland loss rates: 19,000 acres per year for 1922–1954 

and 46,000 acres per year for 1954–1974. The two 

studies using NRI data yielded estimates of 19,000 acres 

per year for 1982–1987 and 32,600 acres per year for 

1992–1997. However, it is important to remember that 

none of these studies, not even the two using NRI data, 

used consistent methodologies, so these rates are not 

comparable and can be used only as estimates of the 

order of magnitude of coastal wetland loss during those 

periods.

Brady and Goebel (2002) drew some interesting 

conclusions from the 1992–1997 data analysis. They 

stated that coastal counties (excluding the Great Lakes) 

occupy 7 percent of the land area, have 20 percent of 

the wetlands, and 31 percent of the gross wetland loss 

(on non-federal, rural lands). They also found that 

42 percent of the loss of wetlands to development 

occurred in coastal counties, and that wetland gains in 

inland counties nearly offset losses, whereas the area 

of wetlands lost in coastal counties was more than 

four times the area of wetlands gained.2

 These results 

pointed to the need for a more in-depth and consistent 

approach to understand the current status and trends 

of coastal wetlands. 

2 This study made no attempt to determine the quality of wetlands that were lost or gained.
10 Statu s and T rend s of Wetland s

Current Study Area, 

Procedures, and Objectives

nalysis of the FWS’ national wetlands status and trends dataset was conducted to provide 

information specifically on the status and extent of wetland resources in the coastal 

watersheds of the Atlantic, Gulf of Mexico, and Great Lakes (Figure 1). The most recent 

national study detailed the status and trends of wetlands from 1998 to 2004 (Dahl 2006). 

In that study, 4,682 randomly selected plots were assessed using digital high-resolution 

imagery to identify change in wetlands, deepwater habitats, and uplands. Each sample 

plot was 4.0 square miles total area (2,560 acres). For each plot, digital aerial imagery was acquired and interpreted 

to identify wetlands, deepwater habitats, and uplands and the changes in areal extent or type of wetland observed 

in the sample plots between 1998 and 2004. This report presents additional information specific to the coastal 

watersheds areas of the Atlantic, Gulf or Mexico, and Great Lakes coasts. Findings were based on 2,265 sample 

plots that fell within the coastal watershed study area.

The United States has been divided and 

subdivided into successively smaller hydrologic 

units, which have been classified into four 

levels by the U.S. Geological Survey (Seaber et 

al. 1994). 

Since approximately 1990, NOAA has used 

a specific methodology to identify coastal 

watersheds. The methodology combined 

information on the extent of tidal influence 

(head of tide) and the U.S. Geological Survey’s 

mapping of watersheds, identifying those 

8-digit hydrologic unit watersheds that 

contained tidal water bodies. A similar method 

was used for Great Lakes wetlands using direct 

drainage to the Great Lakes instead of tidal 

effects. Because of the varying and complex 

state and federal laws governing the placement 

of coastal boundaries, closure of the hydrologic 

units was not provided by the Hydrologic Unit 

Maps along the coastline of the United States 

(Seaber et al. 1994). In this study, the outer 

coastal boundary was determined by the 

extent of the coastal sampling frame used by 

the FWS’ National Wetlands Status and Trends Study for the Atlantic, Gulf of Mexico, and Great Lakes coastal areas. 

The inland study boundary coincided with the corresponding coastal watershed. The total area sampled in these 

three areas was 212.6 million acres3

 (Table 2).

A

Figure 1. Coastal watersheds of the Atlantic, Gulf of Mexico, and Great Lakes.
Statu s and T rend s of Wetland s 11

Table 2. Area (in acres) of 

Coastal Watersheds in this Study.

Coastal Watershed Area (acres)

Atlantic 89,061,946

Gulf of Mexico 67,556,077

Great Lakes 55,936,677

Total Study Area 212,554,700

Wetland changes were determined by intensive analysis 

of the aerial imagery, interpretation of wetland types 

and hydrologic conditions, and determination of the 

changes that occurred between the respective target 

dates. The mean dates of the aerial imagery used to 

determine wetland trends were 1998 and 2004, with 

the difference being an average of 6 years. For this 

study, wetlands 1.0 acres and larger composed the 

target population.4

 Actual results indicated that for 

each wetland category included in the study, the 

minimum size represented was less than 1.0 acre. 

Additional information on the study design, data 

collection, and analysis procedures has been discussed 

by Dahl (2006). 

3 This study incorporated some estuarine embayments not included in the total land area figure. 4 Smaller wetlands were detected and included in the study, but it cannot be determined that all wetlands less than 1.0 acre were 

detected.

Changes were recorded in areal extent or type of 

wetland observed on the sample plots between 1998 

and 2004. Field verification of features on the aerial 

imagery was done for 824 plots (36 percent) during 

2004 and 2005. Field verification addressed questions 

regarding image interpretation, land use coding, and 

attribution of wetland gains or losses. Field work 

was also performed as a quality control measure to 

verify that plot delineations were correct. Verification 

involved field visits to a variety of wetland types and 

geographical settings.

To reflect reliability, each estimate is accompanied by 

a percent coefficient variation expressed as a percent 

(i.e., there is a 95 percent probability that an estimate 

was within the indicated percentage range of the 

true value). The wetland area estimates generated 

for this study include all wetlands regardless of land 

ownership. 
12 Statu s and T rend s of Wetland s

Study Limitations

Due to the limitations of using aerial imagery as 

the primary data source to detect wetlands, certain 

habitats were excluded from this study by design. 

These included:

Reefs — Tropical reef communities (coral or tuberficid 

worm reefs) occurred offshore in south Florida waters. 

These reefs ranged in water depth from less than 1 m 

to 41 m. Coral reefs were concentrated complexes 

of corals and other organisms that constructed a 

limestone structure in shallow waters (Jaap 1984). 

Reefs provided important links to fishery and benthic 

Wetlands

T 

his study used the Fish and Wildlife Service definition of wetland (Cowardin et al. 1979). This definition 

is the national standard for wetland mapping, monitoring and data reporting as determined by the 

Federal Geographic Data Committee (2005). It is a two-part definition as indicated below:

Wetlands are lands transitional between terrestrial and aquatic systems where the water table is 

usually at or near the surface or the land is covered by shallow water. 

For purposes of this classification wetlands must have one or more of the following three 

attributes: (1) at least periodically, the land supports predominantly hydrophytes, (2) the substrate 

is predominantly undrained hydric soil, and (3) the substrate is nonsoil and is saturated with water 

or covered by shallow water at some time during the growing season of each year.

Habitat category definitions are given in synoptic form in Table 3. The reader is encouraged to also review the 

Appendix, which provides complete definitions of wetland types and land use categories used in this study.

Deepwater Habitats

Cowardin et al. (1979) consider wetlands and deepwater 

habitats separately; that is, the term wetland does not 

include deep, permanent water bodies. Deepwater 

habitats are permanently flooded land lying below 

the deepwater boundary of wetlands. Deepwater 

habitats include environments where surface water is 

permanent and often deep, so that water, rather than 

air, is the principal medium in which the dominant 

organisms live, whether or not they are attached to 

the substrate. In lacustrine and riverine systems, the 

boundary between deepwater and wetland habitats is 

approximately 2m (6.6 ft) below low water, or at the 

deepest extent of emergents, shrubs, or trees. For 

the purposes of this study, all lacustrine (lake) and 

riverine (river) waters without visible vegetation were 

considered deepwater habitats.

Upland Habitats

An abbreviated upland classification system patterned 

after the U. S. Geological Survey land classification 

scheme described by Anderson et al. (1976), with five 

generalized categories, was used to describe uplands in 

this study. These categories are also listed in Table 3. 

Definitions of Habitat Categories 

within Coastal Watersheds
Statu s and T rend s of Wetland s 13

Table 3. Wetland, deepwater, and upland categories used in this study. 

The definitions for each category appear in the Appendix.

Salt Water Habitats Common Description

Marine Subtidal* Open Ocean

Marine Intertidal Near shore

Estuarine Subtidal* Open-water/bay bottoms

Estuarine Intertidal Emergents Salt marsh

Estuarine Intertidal Forested/Shrub Mangroves or other estuarine shrubs

Estuarine Intertidal Unconsolidated Shore Beaches/bars/shoals

Riverine* (may be tidal or non-tidal) River systems/channels

Freshwater Habitats

Palustrine Forested Forested wetlands

Palustrine Shrub Shrub wetlands

Palustrine Emergents Inland marshes/emergent wetlands

Palustrine Unconsolidated Shore Shorelines/beaches/bars

Palustrine Unconsolidated Bottom Open-water ponds

Palustrine farmed Farmed wetland

Lacustrine* Deepwater lakes and reservoirs

Uplands

Agriculture Cropland, pasture, managed rangeland

Urban Cities and incorporated developments

Forested Plantations Planted or intensively managed forests; silviculture

Rural Development Non-urban developed areas and Infrastructure

Other Uplands Rural uplands not in any other category; barren lands

*Constitutes deepwater habitat

marine resources and along with seagrasses and 

mangroves formed vital components of the coastal 

ecosystem (Miller and Crosby 1998). The only 

emergent coral reefs found in the conterminous U.S. 

were located in the Florida Keys extending south from 

Miami and Soldier Key to the Dry Tortugas. Coral reef 

extent and changes were not quantified as part of this 

study. Although data from other studies were available 

for only limited geographical sites, there has been 

widespread agreement that coral reef area has been 

declining (Millhouser et al. 1998). 

Oyster (Crassostrea virginica) reefs also occurred in 

the intertidal zone adjacent to marshes or mud flats of 

mid and south Atlantic states and along the Gulf coast. 

There were also a number of artificially created reefs in 

coastal waters. The area of oyster reefs and artificial 

reefs were also not quantified in this study.

Seagrasses or SubmergedAquatic Vegetation 

— Detection of submerged aquatic vegetation required 

specialized techniques such as those described by 

Dierssen et al. (2003) to accurately determine the 

extent of seagrasses. Seagrasses and other submerged 

plants inhabited the intertidal and subtidal zones of 

estuaries and near shore coastal waters (Orth et al. 

1990). Seagrasses have been used to characterize 

water quality because of their widespread distribution, 

important ecological niche and their sensitivity to water 

quality changes. The data presented in this report do 

not include area estimates of seagrasses or submerged 

aquatic vegetation.

Ephemeral Water — Cowardin et al. (1979) did not 

recognize ephemeral water areas as a wetland type 

and ephemeral waters were not included in this study. 

This is consistent with other national Wetlands Status 

and Trends studies conducted by the Fish and Wildlife 

Service (Dahl 2006). 
14 Statu s and T rend s of Wetland s

his study found that there were an 

estimated 39.8 million acres of wetlands 

in the coastal watersheds of the eastern 

United States in 2004. This represented 

38 percent of the estimated total wetland 

acreage in the conterminous United States (Figure 2). 

Of all wetlands found in the coastal watersheds, 34.0 

million acres (86 percent) were freshwater and 5.8 

million acres (14 percent) were saltwater (estuarine or 

marine) as shown in Figure 3.

In the saltwater systems, estuarine emergents were the 

most prevalent type, making up an estimated 71 percent 

(4.1 million acres) of all estuarine and marine wetlands. 

Estuarine shrub wetlands comprised 14 percent of 

the area and non-vegetated saltwater wetlands 15 

percent.

In the freshwater system, forested wetlands made up 

62 percent of the total freshwater wetland area in 

the coastal watersheds. This was the single largest 

freshwater category by area. Other freshwater wetland 

types consisted of shrub wetlands that represented an 

estimated 19 percent of the total freshwater wetland 

area, emergents at 16 percent, and freshwater ponds 

at 3 percent. 

T FIGURE 2. Wetland Area of the Coastal Watersheds 

(Great Lakes, Atlantic and Gulf of Mexico) 

as a Percent of Total Wetland Area in the 

Conterminous United States, 2004.

Wetlands of Coastal 

Watersheds

38%

Remaining 

Wetland Area

62%

FIGURE 3. Wetland Types in the Coastal Watersheds

(Great Lakes, Atlantic and Gulf of Mexico), 2004.

Estuarine and 

Marine Wetland

14%

Freshwater 

Wetland

86%

Results: Status of Wetlands 

in Coastal Watersheds
Statu s and T rend s of Wetland s 15

Watersheds of the Atlantic and Gulf of Mexico coasts have almost the same amount of total wetland area: 

15.9 million and 15.6 million acres, respectively. Watersheds of the Great Lakes had an estimated 8.4 million 

acres. Not surprisingly, wetlands occupy more land area in some watersheds than in others (Figure 4).

Figure 4. Wetland density in the coastal watersheds of the Atlantic, 

Gulf of Mexico, and Great Lakes, 2004.

Low: <10%, Medium: 10.1–17.6%, High: 17.7–32.5%, and Very High: >32.6%.
16 Statu s and T rend s of Wetland s

The estimated changes in wetland area for the coastal watersheds of the Great Lakes, Atlantic, and Gulf of Mexico 

from 1998 to 2004 are shown in Table 4. 

Table 4. Estimated change in wetland area for selected wetland categories for Coastal Watersheds of 

the Great Lakes, Atlantic, and Gulf of Mexico, 1998 to 2004. The coefficient of variation (CV) for each entry 

(expressed as a percentage) is given in parentheses.

Wetland Category

Area in Acres

Estimated Area, 

1998

Estimated Area, 

2004

Change,

1998 to 2004

Change

(percent)

Marine Intertidal 135,970

(18.8)

134,180

(19.0)

-1,860

(69.9)

-1.4

Estuarine Intertidal Non-vegetated1 699,390

(12.3)

704,660

(11.9)

+5,270

(*)

+0.7

Estuarine Intertidal Vegetated2 4,950,430 4,885,450 -64,970 -1.3

All Intertidal (Saltwater) Wetlands 5,818,260 5,756,700 -61,560 -1.1

Freshwater Non-vegetated3 960,980 1,139,940 +178,960 +1.6

Freshwater Forested 21,064,220

(3.7)

21,100,450

(3.7)

+36,230

(*)

+0.2

Freshwater Shrub 6,735,910

(5.4)

6,293,530

(5.7)

-422,380

(42.5)

-6.6

Freshwater Emergent 5,612,020

(7.0)

5,539,680

(7.0)

-72,340

(101.3)

-1.3

Freshwater Vegetated Wetlands4 33,412,150 32,933,650 -478,500 -1.4

All Freshwater Wetlands 34,373,130 34,073,600 -299,540 -0.9

All Wetlands 40,191,380 39,830,280 -361,100 -0.9

*Statistically unreliable

1

 Includes the category: Estuarine Intertidal Unconsolidated Shore.

2

 Includes the categories: Estuarine Intertidal Emergent and Estuarine Intertidal Shrub.

3

 Includes the categories: Palustrine Aquatic Bed, Palustrine Unconsolidated Bottom and Palustrine Unconsolidated Shore.

4

 Includes the categories: Palustrine Emergent, Palustrine Forested and Palustrine Shrub.

Considering saltwater and freshwater systems together, 

there was an estimated loss of 361,100 wetland acres in 

the coastal watersheds between 1998 and 2004. Both 

the Atlantic and the Gulf of Mexico coasts experienced 

net wetland losses of 14,980 and 370,760 acres, 

respectively. The Great Lakes coastal watersheds had 

an estimated net gain of 24,650 acres. For all three 

coastal watersheds, this equated to an average annual 

net loss of about 60,000 acres over the 6-year period 

of this study. There were wetlands gains in each of the 

coastal regions, but wetland losses far outweighed the 

gains, especially in the Gulf of Mexico (Figure 5).
Statu s and T rend s of Wetland s 17

Because Cowardin et al. (1979) defines “estuarine” and “marine” wetlands as saltwater systems, no 

estuarine or marine wetlands were identified in the 

coastal watersheds of the Great Lakes portion of this 

study. Shoreline wetlands of the Great Lakes were 

included with other freshwater wetlands in the Great 

Lakes coastal watersheds.

The majority of estuarine and marine wetlands fall into 

three types: estuarine intertidal emergent wetlands 

(salt and brackish water marshes), estuarine shrub 

wetlands (mangrove swamps and other salt-tolerant 

woody species), and estuarine and marine intertidal 

non-vegetated wetlands. The latter category included 

exposed coastal beaches subject to tidal flooding, as 

well as sand bars, tidal mud flats, shoals, and sand 

spits. 

Coastal wetlands are subjected to a multitude of 

anthropogenic stressors originating from the landward 

side, as well as natural forces affecting change 

from the sea. Stressors originating from land-based 

activities include dredging, filling, shoreline hardening, 

and a multitude of other human activities that 

destroy wetlands. Seaward, events such as coastal 

storms, tidal surge causing erosion and deposition, 

saltwater intrusion, and inundation have the ability 

to modify coastal wetland type and extent. Kennish 

(2004) has summarized the major threats to estuarine 

environments that include habitat loss, introduction of 

contaminants, invasive species, freshwater diversion, sea 

level rise, and subsidence, among others. EPA also has 

provided indicators of coastal condition and identified 

sources of environmental degradation affecting coastal 

ecosystems to include discharges from municipalities 

and industries and nonpoint-source runoff (EPA 2008). 

FIGURE 5. Wetland Gains and Losses in the Coastal Watersheds of the 

Atlantic, Gulf of Mexico, and Great Lakes, 1998 to 2004.

Acres

Atlantic Gulf Great Lakes

Trends in Coastal Saltwater Wetlands – 1998 to 2004
18 Statu s and T rend s of Wetland s

Between 1998 and 2004, saltwater wetlands declined 

by slightly more than 1.0 percent. Estimated estuarine 

and marine wetland losses (all intertidal wetland types) 

were over twice as great along the Gulf of Mexico as 

compared to the Atlantic coast (Table 5). Over 44,000 

acres of these saltwater wetlands were lost in Gulf of 

Mexico coastal watersheds during this study period.

The results from this study indicated that intertidal 

marine non-vegetated wetland area (tidal flats and 

shoals) declined by an estimated 6.0 percent along 

the coastal areas of the Gulf of Mexico, whereas 

they remained stable along the coastal areas of the 

Atlantic. 

The Gulf of Mexico had an estimated 36 percent more 

area of saltwater wetland than the Atlantic in 2004. 

The watersheds along the Gulf of Mexico contained 

greater area of all wetland types with the exception 

of marine intertidal flats and shoals. Both the Atlantic 

and Gulf of Mexico coasts lost saltwater vegetated 

wetlands between 1998 and 2004. Estuarine intertidal 

vegetated wetland (saltwater marsh and shrubs) in 

both of these regions declined by an estimated 65,000 

acres (1.3 percent) overall.

Estuarine emergents (salt marsh) sustained the largest 

losses, declining by an estimated 1.0 and 1.8 percent in 

the Atlantic and Gulf of Mexico, respectively. Estuarine 

salt marsh exhibited the largest declines of any 

saltwater wetland type on both the Atlantic and Gulf of 

Mexico coasts, declining by an estimated 62,500 acres. 

The ecological value of estuarine salt marsh wetlands 

has been well documented by a number of researchers 

(Livingston 1984; Montague and Wiegert 1990; Watzin 

and Gosselink 1992; Mitsch and Gosselink 2000; EPA 

2008). The total monetary value of coastal wetlands 

for storm protection has been evaluated by Costanza 

et al. (2008). These studies indicate that the loss of 

coastal wetland area has had adverse ecological and 

economic effects. 
Statu s and T rend s of Wetland s 19

Table 5. Estimated Changes to Saltwater (Estuarine and Marine) Wetlands in the Coastal Watersheds of 

the Atlantic and Gulf of Mexico Coasts, 1998 to 2004. Percent Coefficient of Variation was Expressed as 

(Standard Deviation/Mean) X 100.

Estimated Changes to Saltwater Wetlands of the Atlantic Coast

Atlantic Coast—Wetland Category

Area in Acres

Estimated Area, 

1998

Estimated Area, 

2004

Change,

1998 to 2004

Change

(percent)

Marine Intertidal 105,130

(21.9)

105,160

(21.9)

+30

(71.4)

—

Estuarine Non-vegetated1 287,920

(21.4)

287,680

(20.8)

-240

(*)

-0.1

Estuarine Emergent 1,722,900

(6.0) 

1,704,460

(6.0)

-18,430

(*)

-1.0

Estuarine Shrub 119,430

(16.6)

118,320

(16.6)

 -1,110

(*)

-0.9

Estuarine Vegetated2 1,842.320

(5.8)

1,822,780

(5.7)

 -19,540

(*)

-1.0

All Intertidal Wetlands - Atlantic 2,267,850

(6.1)

2,248,100

(6.0)

-19,750

(*)

-0.9

Estimated Changes to Saltwater Wetlands of the Gulf of Mexico Coast

Wetland Category

Area in Acres

Estimated Area, 

1998

Estimated Area, 

2004

Change,

1998 to 2004

Change

(percent)

Marine Intertidal 30,830

(38.2)

28,950

(40.3)

-1,890

(68.8)

-6.1

Estuarine Non-vegetated1 411,470

(14.5)

416,980

(14.1)

+5,510

(*)

+1.3

Estuarine Emergent 2,428,970

(5.8)

2,384,880

(5.9)

-44,090

(20.0)

-1.8

Estuarine Shrub 679,140

(14.8)

677,800

(14.8)

-1,340

(69.6)

-0.2

Estuarine Vegetated2 3,108,110

(5.6)

3,062,680

(5.7)

-45,430

(19.4)

-1.5

All Intertidal Wetlands - Gulf of Mexico 

Coast

3,550,400

(5.2)

3,508,600

(5.3)

-44,810

(24.7)

-1.2

*Statistically unreliable

1

 Includes Estuarine Intertidal Unconsolidated Shore

2

 Sum of Estuarine Emergent and Estuarine Shrub

Most saltwater wetland losses from both the Atlantic and the Gulf of Mexico resulted from inundation or saltwater 

intrusion (Figure 5). This was observed most extensively in a region of the Atlantic coast extending south from Rhode 

Island Sound to the mouth of Chesapeake Bay, which included areas along the coastal states of New York, New 

Jersey, Delaware, Maryland, and Virginia. Wetlands were also lost to open saltwater in the western Gulf of Mexico, 
20 Statu s and T rend s of Wetland s

principally along the coastlines of 

Mississippi, Louisiana, and Texas. 

These findings coincide with the 

Coastal Vulnerability Index for the 

U.S. Atlantic coast that shows the 

relative vulnerability of the coast 

to changes due to future rise in sea 

level (Thieler and Hammar-Klose 

1999).

Along the coastal fringe there 

are regional differences in 

geomorphology, land use, and 

development trends. This may 

explain why certain regions of the 

Atlantic coastline seemed to be 

particularly susceptible to wetland loss as a result of 

inundation or saltwater intrusion. Thieler and HammarKlose (1999) found portions of the Chesapeake Bay 

region vulnerable to sea-level rise as a result of low 

coastal slope, saltwater wetland as a common landform 

type, and a relatively high rate of sea-level rise. In 

contrast, the coastline of New England may be much 

less vulnerable to sea-level rise due to its steep coastal 

slope, rocky shoreline, and larger tidal range.

It has been speculated that the process of coastal 

wetland retreat caused by saltwater inundation may 

be more prevalent along the southeastern coastal 

plain than in the northern Atlantic region. Williams 

et al. (1999) found that along portions of the west 

coast of Florida, saltwater intrusion might be replacing 

forested habitats with salt marsh or more salt tolerant 

species—perhaps a more subtle ecological shift than 

the drowning of coastal vegetation by rising sea levels 

associated with saltwater inundation. However, the 

results from this study did not find coastal saltwater 

wetland losses due to inundation or saltwater intrusion 

along the coastal plain of the southeastern Atlantic, 

nor on the Florida coastline of the Gulf of Mexico. 

Intertidal wetlands lost to open saltwater were most 

prevalent in the northern to mid-Atlantic regions, for 

reasons undetermined by this study.

There were small losses of saltwater wetlands 

attributable to development or other direct human 

activities. Estimated losses of these types to urban 

and rural development was 1.5 percent of all saltwater 

wetland losses recorded during the period of this study. 

Many federal and state agencies are involved in the 

regulation, protection, and monitoring of saltwater 

wetlands, coastal areas, and the species that inhabit 

them. Additionally, coastal states also have established 

coastal zone management plans, growth management 

plans, and coastal resource agencies (Dahl 2000). These 

programs and policies appear to have been effective in 

limiting development in saltwater wetlands. There was 

also very little wetland area restored in the intertidal 

systems of the Atlantic or Gulf of Mexico between 

1998 and 2004. The most notable gains in saltwater 

wetlands were the result of conversion from deepwater 

and freshwater wetlands along the Atlantic coast, 

although these gains in area were negated by losses to 

open saltwater on both coastlines. Wetland restoration 

(re-establishment) or creation is more problematic 

in the coastal watersheds, where land values fueled 

by continued development are high. Additionally, 

successful restoration of many coastal wetlands hinges 

on consideration of physical processes including 

flow, circulation, transport of nutrients, salinity, and 

sediments (Sanders and Arega 2002).

Open Saltwater — 96.14%

FIGURE 6. Attribution of loss or conversion of saltwater wetlands in the 

coastal watersheds of the Atlantic and Gulf of Mexico, 1998 to 2004.

Freshwater Wetlands — 0.32%

Urban Development — 0.86%

Other Uplands — 2.01%

Rural Development — 0.67%
Statu s and T rend s of Wetland s 21

Trends in Freshwater Coastal Wetlands – 1998 to 2004

An estimated 33 percent of all freshwater wetland area in the conterminous United States is found in the coastal watersheds of the eastern United States (Table 6). Freshwater emergent wetlands generally contained 

shallow water and were dominated by herbaceous plants. They included areas known as marsh, swale, slough, 

wet prairie, wet savanna, reed swamps, and glades. Freshwater emergent wetland area declined in all coastal 

watersheds between 1998 and 2004.

Table 6. Estimated Freshwater Wetland Acreage for Coastal Watersheds of the Atlantic, Gulf of Mexico 

and Great Lakes as Compared to the Conterminous United States, 2004.

Wetland Category

Wetland Area in Acres

Coastal 

Watersheds

2004

Conterminous

U.S.

2004

% Wetland

Area in Coastal

Watersheds, 2004

Freshwater Non-Vegetated1 1,139,940 6,229,600 18%

Freshwater Forested 21,100,450 52,031,400 41%

Freshwater Shrub 6,293,530 17,641,400 36%

Freshwater Emergent 5,539,680 26,147,000 21%

Freshwater Vegetated Wetland2 32,933,650 95,819,800 34%

All Freshwater Wetlands 34,073,580 102,453,800 33%

1

 Includes the categories: Palustrine Aquatic Bed, Palustrine Unconsolidated Bottom and Palustrine Unconsolidated Shore.

2

 Includes the categories: Palustrine Emergent, Palustrine Forested and Palustrine Shrub.

Freshwater wetlands in coastal watersheds exhibited 

trends similar to those occurring elsewhere in the 

nation. Non-vegetated freshwater ponds, both natural 

and artificial, increased in area. Estimated pond acreage 

increased by 18.0, 19.4, and 19.3 percent in the Atlantic, 

Gulf of Mexico, and Great Lakes coastal watersheds, 

respectively (Table 7).

Collectively, freshwater wetlands in coastal watersheds 

declined by an estimated 0.9 percent between 1998 

and 2004. Freshwater shrubs declined the most of 

any freshwater wetland type, as an estimated 442,400 

acres were lost during the period of this study. Large 

losses of this freshwater wetland type in the Atlantic 

and Gulf of Mexico coastal watersheds accounted for 

this decline. There was a net gain in wetland shrub 

area in the Great Lakes. The freshwater vegetated 

wetlands (forest, shrub, and emergent types) found 

in all watersheds included in this study declined by 

an estimated 1.4 percent, whereas freshwater ponds 

increased by almost 1.6 percent.
22 Statu s and T rend s of Wetland s

Table 7. Estimated Changes to Freshwater Wetlands in the Coastal Watersheds of the Atlantic, 

Gulf of Mexico and Great Lakes, 1998 to 2004. Percent Coefficient of Variation was Expressed 

as (Standard Deviation/Mean) X 100

Estimated Changes to Freshwater Wetlands in Coastal Watersheds of the Atlantic Coast, 1998 to 2004

Wetland Category

Area in Acres

Estimated Area, 

1998

Estimated Area, 

2004

Change,

1998 to 2004

Change

(percent)

Freshwater Non-vegetated (ponds)1 404,300

(7.6)

475,370

(9.2)

+71,070

(31.2)

+18.0

Freshwater Forested 8,454,700

(4.9)

8,771,720

(4.8)

+317,020

(85.4)

+3.7

Freshwater Shrub 3,000,320

(7.9)

2,627,630

(8.2)

-372,690

(33.0)

-12.0

Freshwater Emergent 1,799,940

(10.9)

1,789,300

(10.9)

-10,630

(*)

-0.6

Freshwater Vegetated2 13,254,960

(4.0)

13,188,660

(4.0)

-66,300

(*)

-0.5

All Freshwater Wetlands 13,659,260

(3.9)

13,664,030

(3.8)

+4,770

(*)

+0.03

All Wetlands 

(Atlantic Coast Watersheds)3

15,927,100

(3.4)

15,912,120

3.4

-14,980

(*)

-0.1

Estimated Changes to Wetlands in Coastal Watersheds of the Gulf of Mexico Coast, 1998 to 2004

Wetland Category

Area in Acres

Estimated Area, 

1998

Estimated Area, 

2004

Change,

1998 to 2004

Change

(percent)

Freshwater Non-vegetated (ponds)1 349,210

(6.9)

417,030

(7.5)

+67,820

(18.1)

+19.4

Freshwater Forested 7,453,120

(4.8)

7,324,780

(5.1)

-128,340

(77.5)

-1.7

Freshwater Shrub 1,800,690

(8.6)

1,581,930

(8.9)

-218,760

(28.0)

-12.2

Freshwater Emergent 2,779,720

(9.9)

2,730,050

(9.9)

-49,670

(67.3)

-1.8

Freshwater Vegetated2 12,033,530

(4.1)

11,636,760

(4.2)

-396,770

(24.0)

-3.3

All Freshwater Wetlands 12,382,740

(4.0)

12,053,790

(4.0)

-328,950

(28.9)

-2.7

All Wetlands 

(Gulf of Mexico Coast Watersheds)3

15,933,140

(3.3)

15,562,400

(3.3)

-370,760

(25.8)

-2.3
Statu s and T rend s of Wetland s 23

Table 7. Estimated Changes to Freshwater Wetlands in the Coastal Watersheds of the Atlantic, 

Gulf of Mexico and Great Lakes, 1998 to 2004. Percent Coefficient of Variation was Expressed 

as (Standard Deviation/Mean) X 100 (continued)

Estimated Changes to Wetland Area for Freshwater Wetlands in Coastal Watersheds of the Great Lakes, 

1998 to 2004

Wetland Category

Area in Acres

Estimated Area, 

1998

Estimated Area, 

2004

Change,

1998 to 2004

Change

(percent)

Freshwater Non-vegetated (ponds)1 207,470

(12.1)

247,540

(10.0)

+40,570

(22.7)

+19.3

Freshwater Forested 5,156,400

(9.8)

5,003,950

(9.8)

-152,450

(75.0)

-3.0

Freshwater Shrub 1,934,900

(12.0)

2,083,970

(12.4)

+149,060

(76.2)

+7.7

Freshwater Emergent 1,032,360

(12.4)

1,020,320

(12.6)

-12,040

(*)

-1.0

Freshwater Vegetated2 8,123,660

(8.2)

8,108,240

(8.2)

-15,430

(74.6)

-0.2

All Freshwater Wetlands 

(Great Lakes Watersheds)

8,331,130

(8.0)

8,355,780

(7.9)

+24,650

(44.0)

+0.3

*Estimate statistically unreliable.

1

 Includes the categories: Palustrine Aquatic Bed, Palustrine Unconsolidated Bottom, and Palustrine Unconsolidated Shore

2

 Includes the categories: Palustrine Forested, Palustrine Shrub and Palustrine Emergent

3

 Includes all freshwater and saltwater wetlands

In the Great Lakes and the Atlantic regions, freshwater 

forested and shrub wetlands reflect acreage changes 

(interchange between wetland shrub and forested 

categories) largely as a result of areas being harvested 

for timber and becoming shrub wetlands, then maturing 

and returning as forested wetlands. Forest and shrub 

wetland area gains and losses were almost equal 

between 1998 and 2004 in the Great Lakes and Atlantic. 

Forested wetlands of the Gulf of Mexico region were 

represented by many different ecological associations, 

and included wet pine flatwoods, mixed hardwoods, 

river swamps, cypress domes, and hydric hammocks. 

These forested resources sustained substantial losses 

overall. 

Overall, the Gulf of Mexico coastal watersheds exhibited 

substantial losses in freshwater wetlands. An estimated 

396,800 acres of freshwater vegetated wetlands were 

lost between 1998 and 2004. This rate of loss was 

6 times higher than the rate of freshwater vegetated 

wetlands losses in the Atlantic coastal watersheds. The 

estimated wetland losses for all wetland types in the 

Gulf of Mexico were almost 25 times higher than those 

estimates for the Atlantic (371,000 acres versus 15,000 

acres lost) over the course of this study (Figure 7 on 

page 24).

The losses of all freshwater wetlands for the Atlantic, 

Gulf of Mexico, and Great Lakes coastal watersheds 

have been attributed to various causes, as shown in 

Figure 8. Coastal development in both rural and 

urban areas, loss to deepwater habitats (reservoirs), 

silvicultural activities, drainage, and filling for other 

types of development contributed to the losses of 
24 Statu s and T rend s of Wetland s

coastal freshwater wetlands along the Gulf of 

Mexico. The population of coastal counties in the 

Gulf Coast region increased more than 100 percent 

between 1960 and 2000 (U.S. Census Bureau 2003). 

Because a disproportionate percentage of the 

nation’s population lives in coastal areas, activities 

that support municipalities, commerce, industry, and 

tourism have created environmental pressures (EPA 

2005). These development pressures have resulted 

in substantial physical changes along many areas of 

the coast, and coastal wetlands continue to be lost to 

residential and commercial development (EPA 2008).

Other Development 

Activities

59.45%

FIGURE 8. Attribution of Loss or Conversion of Freshwater Wetlands in the Coastal Watersheds of the 

Atlantic, Gulf of Mexico and Great Lakes, 1998 to 2004

Agriculture 

3.60%

Deepwater

14.50%

Intertidal Wetlands

0.05%

Urban and Rural 

Development

22.40%

FIGURE 9. Net Gains and Losses (in acres) of 

Coastal Wetlands in the Great Lakes Coastal 

Watersheds, 1998 to 2004. 

Acres

Deepwater Development Other Lands Agriculture

-10,000

-5,000

0

5,000

10,000

15,000

20,000

25,000

2,500

-6,000

22,800

7,000

Figure 7. Areas of greatest coastal wetland loss in Gulf of Mexico.

Estimated net gains in freshwater wetland area were 

seen in both the Great Lakes and the Atlantic coastal 

watersheds. The Atlantic coastal region gained about 

4,800 acres of freshwater wetlands between 1998 and 

2004. The Great Lakes had the largest estimated increase 

in freshwater wetland area. There was a net gain of an 

estimated 24,650 acres over the study period, with wetland 

area coming from fresh deepwater habitats, agricultural 

lands, and the other uplands category (Figure 9). 
Statu s and T rend s of Wetland s 25

n 2008, NOAA, FWS, the Fish America Foundation, and other partners restored a large area of 

St. Vincent Island, a 12,000 acre barrier island in the Gulf of Mexico. Nearly 2,000 acres of 

wetland needed to be restored as a result of 45 miles of roads blocking natural tidal flow for 

many years. These wetlands and the surrounding Apalachicola Bay serve as a nursery for a 

wide variety of fish species, including the striped bass, Gulf sturgeon, tarpon, red drum, spotted 

seatrout and Gulf flounder. St. Vincent Island also provides sanctuary for a number of endangered and threatened 

species. Loggerhead, green, and leatherback sea turtles come ashore to nest on its beaches, and wood storks stop 

here during their migrations. 

I

Restoration on an island is extremely complicated 

logistically. All machinery, equipment, and personnel 

had to be barged to the island, offloaded at the 

docking location, and then hauled to the far end of the 

island where the work took place. Working in marine 

conditions created additional challenges, as the harsh 

saline environment increased wear and equipment 

break-downs, the soft sediment made it difficult to 

move machinery, and the sensitivity of the surrounding 

environment required special consideration be given to 

methods and best management practices. All of these 

factors added to the cost and time required to complete 

the restoration.

Today, swaths of wetlands are recovering natural 

function across areas once blocked by roads and 

disrupted by water diversion. Birds and fish are also 

returning as tidal flow returns to normal and water 

quality improves. In combination with neighboring 

restoration efforts at Tates Hell State Forest, St. Joe 

Bay Buffer Preserve and Florida Fish and Wildlife 

Commission’s Apalachicola Wildlife and Environmental 

Area, the St. Vincent Island restoration will ensure 

that the entire region benefits from this conservation 

success. 

Case Study: Restoration of Florida’s St. Vincent Island

Figure 10. St. Vincent Island restoration site, Florida, post-restoration.
26 Statu s and T rend s of Wetland s

oastal watersheds of the eastern United States contained about 11 percent of the total land area 

in the lower 48 states and 38 percent of the wetlands by area. Yet these coastal areas experienced 

roughly the same amount of wetland loss from 1998 to 2004 as occurred in the entire conterminous 

United States in the 1990s. As with other status and trends reports on wetland acreage trends, 

these data do not address the functionality of the wetlands lost, gained, or remaining unchanged Cin acreage.

More than half of the U.S. population lives in coastal 

areas, and people continue to move to coastal areas 

every year. Development was a major factor in the loss 

of coastal wetlands, especially along the Atlantic and 

Gulf of Mexico coasts, where it was the overwhelming 

factor in the loss of freshwater wetlands.

Rising sea level, coastal subsidence, and erosion 

processes were also important factors affecting 

wetland loss and distribution, especially along 

coastlines where the wetlands cannot migrate inland 

because the shorelines are artificially hardened or too 

steep. Coastal wetlands also appear to be vulnerable 

to saltwater inundation in areas of the northern to 

mid-Atlantic and the western Gulf of Mexico. To fully 

recognize the impacts of climate change on coastal 

wetlands, there will need to be a better understanding 

of the linkages among upland, wetland, and oceanic 

responses to changing conditions. 

A majority of the coastal wetland loss (61,800 acres per 

year) from 1998 to 2004 occurred in the Gulf of Mexico. 

The loss of wetlands in southern Louisiana, estimated 

at about 18,500 acres per year (U.S. Geological Survey 

1995) accounted for only about one-third of the 

wetland losses observed; much of the remaining losses 

occurred in the upper portions of the watersheds and 

were due to a combination of human-induced factors 

including urban and rural development, silvicultural 

operations, and other activities that drained or filled 

wetlands. In effect, the same human uses that are 

desired of coastal habitats are reducing their area and 

lessening their value.

That is not to say that wetland losses are not occurring 

in interior of the conterminous United States as well. 

But those losses have been offset by wetland gains 

that have resulted from re-establishment and creation 

in inland regions, whereas in the coastal watersheds 

of the Atlantic and Gulf of Mexico they have not been 

similarly offset. Wetland restoration in coastal areas 

is generally more expensive and logistically more 

difficult than wetland restoration in inland areas due, 

in part, to higher land costs, fewer suitable sites, and 

competing interests (e.g., development). Additionally, 

successful restoration of many coastal wetlands hinges 

on consideration of physical processes including 

flow, circulation, transport of nutrients, salinity, and 

sediments (Sanders and Arega 2002).

However, the results of this study suggest that 

wetland protection and restoration require more 

attention in coastal watersheds. Otherwise, there is 

a risk of reducing or losing the substantial ecological, 

commercial, economic, and recreational services they 

provide. Public policymakers and coastal managers 

have been confronted with the daily task of finding 

a balance between benefiting from economic growth 

and mitigating the effects of growth on coastal 

environments. This task will become more challenging 

as the coastal population continues to grow in a limited 

space, thereby exacting more pressure on the remaining 

natural habitats, including wetlands. 

Summary and Conclusions
Statu s and T rend s of Wetland s 27

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Statu s and T rend s of Wetland s 29

APPENDIX: 

Definitions of Habitat Categories

WETLANDS 5

n general terms, wetlands are lands where saturation with water is the dominant factor determining 

the nature of soil development and the types of plant and animal communities living in the soil 

and on its surface. The single feature that most wetlands share is soil or substrate that is at least 

periodically saturated with or covered by water. The water creates severe physiological problems for 

all plants and animals except those that are adapted for life in water or in saturated soil.

5 Adapted from Cowardin et al. 1979. 6 The U.S. Fish and Wildlife Service has published the list of plant species that occur in wetlands of the United States (Reed 1988). 7 U.S. Department of Agriculture has developed the list of hydric soils for the United States (U.S. Department of Agriculture 1991).

Wetlands are lands transitional between 

terrestrial and aquatic systems where the 

water table is usually at or near the surface 

or the land is covered by shallow water. For 

purposes of this classification wetlands must 

have one or more of the following three 

attributes: (1) at least periodically, the land 

supports predominantly hydrophytes6, (2) the 

substrate is predominantly undrained hydric 

soil7, and (3) the substrate is non-soil and is 

saturated with water or covered by shallow 

water at some time during the growing season 

of each year.

The term wetland includes a variety of areas that fall 

into one of five categories: (1) areas with hydrophytes 

and hydric soils, such as those commonly known 

as marshes, swamps, and bogs; (2) areas without 

hydrophytes but with hydric soils—for example, flats 

where drastic fluctuation in water level, wave action, 

turbidity, or high concentration of salts may prevent 

the growth of hydrophytes; (3) areas with hydrophytes 

but non-hydric soils, such as margins of impoundments 

or excavations where hydrophytes have become 

established but hydric soils have not yet developed; 

(4) areas without soils but with hydrophytes such as 

the seaweed covered portions of rocky shores; and (5) 

wetlands without soil and without hydrophytes, such 

as gravel beaches or rocky shores without vegetation.

Marine System – The marine system consists of 

the open ocean overlying the continental shelf and 

its associated high energy coastline. Marine habitats 

are exposed to the waves and currents of the open 

ocean. Salinity exceeds 30 parts per thousand, with 

little or no dilution except outside the mouths of 

estuaries. Shallow coastal indentations or bays without 

appreciable freshwater inflow and coasts with exposed 

rocky islands that provide the mainland with little or no 

shelter from wind and waves are also considered part 

of the Marine System because they generally support a 

typical marine biota. 

Estuarine System – The estuarine system consists 

of deepwater tidal habitats and adjacent tidal wetlands 

that are usually semi enclosed by land but have open, 

partly obstructed, or sporadic access to the open ocean 

and in which ocean water is at least occasionally diluted 

by freshwater runoff from the land. The salinity may 

be periodically increased above that of the open ocean 

by evaporation. Along some low energy coastlines 

there is appreciable dilution of sea water. Offshore 

areas with typical estuarine plants and animals, such 

as red mangroves (Rhizophora mangle) and eastern 

oysters (Crassostrea virginica), are also included in the 

Estuarine System.

I
30 Statu s and T rend s of Wetland s

M a r i n e a n d Estu a r i n e 

S u b syst e ms

Subtidal – The substrate is continuously 

submerged by marine or estuarine waters.

Intertidal – The substrate is exposed and 

flooded by tides. Intertidal includes the splash 

zone of coastal waters.

Palustrine System – The palustrine (freshwater) 

system includes all nontidal wetlands dominated by 

trees, shrubs, persistent emergents, emergent mosses 

or lichens, farmed wetlands, and similar wetlands 

that occur in tidal areas where salinity due to ocean 

derived salts is below 0.5 parts per thousand. It also 

includes wetlands lacking such vegetation, but with all 

of the following four characteristics: (1) area less than 

20 acres (8 ha); (2) an active wave formed or bedrock 

shoreline features are lacking; (3) water depth in the 

deepest part of a basin less than 6.6 feet (2 meters) at 

low water; and (4) salinity due to ocean derived salts 

less than 0.5 parts per thousand. 

Cla ss e s

Unconsolidated Bottom – Unconsolidated bottom 

includes all wetlands with at least 25 percent cover of 

particles smaller than stones, and a vegetative cover less 

than 30 percent. Examples of unconsolidated substrates 

are: sand, mud, organic material, cobble gravel.

Aquatic Bed – Aquatic beds are dominated by 

plants that grow principally on or below the surface 

of the water for most of the growing season in most 

years. Examples include seagrass beds, pondweeds 

(Potamogeton spp.), wild celery (Vallisneria americana), 

waterweed (Elodea spp.), and duckweed (Lemna spp.).

Rocky Shore – Rocky shore includes wetland 

environments characterized by bedrock, stones, or 

boulders which singly or in combination have an areal 

cover of 75 percent or more and an areal vegetative 

coverage of less than 30 percent.

Unconsolidated Shore – Unconsolidated shore 

includes all wetland habitats having two characteristics: 

(1) unconsolidated substrates with less than 75 percent 

areal cover of stones, boulders or bedrock and; (2) less 

than 30 percent areal cover of vegetation other than 

pioneering plants.
Statu s and T rend s of Wetland s 31

Emergent Wetland – Emergent wetlands are 

characterized by erect, rooted, herbaceous hydrophytes, 

excluding mosses and lichens. This vegetation is present 

for most of the growing season in most years. These 

wetlands are usually dominated by perennial plants.

Shrub Wetland – Shrub Wetlands include areas 

dominated by woody vegetation less than 20 feet (6 

meters) tall. The species include true shrubs, young 

trees, and trees or shrubs that are small or stunted 

because of environmental conditions. 

Forested Wetland – Forested Wetlands are 

characterized by woody vegetation that is 20 feet (6 m) 

tall or more. 

Farmed Wetland – Farmed wetlands are wetlands 

that meet the Cowardin et al. definition where the soil 

surface has been mechanically or physically altered 

for production of crops, but where hydrophytes will 

become reestablished if farming is discontinued. 

DEEPWATER HABITATS

Wetlands and deepwater habitats were defined 

separately because the term wetland does not include 

deep, permanent water bodies. For conducting status 

and trends studies, Riverine and Lacustrine were 

considered deepwater habitats. Elements of Marine 

or Estuarine systems can be wetland or deepwater. 

Palustrine includes only wetland habitats.

Deepwater habitats were permanently flooded land 

lying below the deepwater of wetlands. Deepwater 

habitats include environments where surface water is 

permanent and often deep, so that water, rather than 

air, is the principal medium in which the dominant 

organisms live, whether or not they were attached to 

the substrate. As in wetlands, the dominant plants were 

hydrophytes; however, the substrates were considered 

nonsoil because the water is too deep to support 

emergent vegetation (U.S. Department of Agriculture 

1975).

Riverine System – The Riverine system includes 

deepwater habitats contained in a channel, with the 

exception of habitats with water containing ocean 

derived salts in excess of 0.5 parts per thousand. A 

channel is “an open conduit either naturally or 

artificially created which periodically or continuously 

contains moving water, or which forms a connecting 

link between two bodies of standing water” (Langbein 

and Iseri 1960).

Lacustrine System – The lacustrine system 

includes deepwater habitats with all of the following 

characteristics: (1) situated in a topographic depression 

or a dammed river channel; (2) lacking trees, shrubs, 

persistent emergents, emergent mosses or lichens 

with greater than 30 percent coverage; (3) total area 

exceeds 20 acres (8 ha). 

UPLANDS

Agriculture8 – Agricultural land may be defined 

broadly as land used primarily for production of food 

and fiber. Agricultural activity is evidenced by distinctive 

geometric field and road patterns on the landscape 

and the traces produced by livestock or mechanized 

equipment. Examples of agricultural land use include 

cropland and pasture; orchards, groves, vineyards, 

nurseries, cultivated lands, and ornamental horticultural 

areas including sod farms; confined feeding operations; 

and other agricultural land including livestock feed lots, 

farmsteads including houses, support structures (silos) 

and adjacent yards, barns, poultry sheds, etc.

8 Adapted from Anderson et al. 1976.
32 Statu s and T rend s of Wetland s

Urban: Urban land is comprised of areas of intensive use 

in which much of the land is covered by structures (high 

building density). Urbanized areas are cities and towns 

that provide the goods and services needed to survive 

by modern day standards through a central business 

district. Services such as banking, medical and legal 

office buildings, supermarkets, and department stores 

make up the business center of a city. Commercial 

strip developments along main transportation routes, 

shopping centers, contiguous dense residential areas, 

industrial and commercial complexes, transportation, 

power and communication facilities, city parks, ball 

fields and golf courses can also be included in the 

urban category.

Forested Plantation: Forested plantations include 

areas of planted and managed forest stands. Planted 

pines, Christmas tree farms, clear cuts, and other 

managed forest stands, such as hardwood forestry are 

included in this category. Forested plantations can be 

identified by observing the following remote sensing 

indicators: 1) trees planted in rows or blocks; 2) 

forested blocks growing with uniform crown heights; 

and 3) logging activity and use patterns.

Rural Development: Rural developments occur 

in sparse rural and suburban settings outside distinct 

urban cities and towns. They are characterized by nonintensive land use and sparse building density. Typically, 

a rural development is a cross-roads community that 

has a corner gas station and a convenience store 

which are surrounded by sparse residential housing 

and agriculture. Scattered suburban communities 

located outside of a major urban center can also be 

included in this category as well as some industrial and 

commercial complexes; isolated transportation, power, 

and communication facilities; strip mines; quarries; 

and recreational areas such as golf courses, etc. Major 

highways through rural development areas are included 

in the rural development category.

Other Land Use: Other Land Use is composed of 

uplands not characterized by the previous categories. 

Typically these lands would include native prairie; 

unmanaged or non-patterned upland forests and scrub 

lands; and barren land. Lands in transition may also 

fit into this category. Transitional lands are lands in 

transition from one land use to another. They generally 

occur in large acreage blocks of 40 acres (16 ha) or 

more and are characterized by the lack of any remote 

sensor information that would enable the interpreter 

to reliably predict future use. The transitional phase 

occurs when wetlands are drained, ditched, filled, 

leveled, or the vegetation has been removed and the 

area is temporarily bare.
For more information:

www.nmfs.noaa.gov/habitat

www.fws.gov/wetlands
National Oceanic and Atmospheric Administration

National Marine Fisheries Service

U.S. Department of Interior

Fish and Wildlife Service