Under the Emergency Wetlands Resources Act of 1986, the Department of the Interior’s Fish and Wildlife Service is required to submit decadal reports to Congress on wetland status and trends. The reports provide the data necessary to effectively manage wetlands and determine if the goal of no net loss of wetlands is achieved. 

This is the sixth report in a series of congressionally mandated reports spanning nearly 70 years. Covering the period between 2009 to 2019, this report provides the most comprehensive and contemporary information available on the amount and type of wetlands in the conterminous U.S. and changes in these characteristics over time. It highlights the importance of wetlands in providing ecosystem services, as well as the effects of wetland change. 

For more information about wetlands and their importance to the Service see https://www.fws.gov/initiative/protecting-wildlife/wetlands. To read previous status and trends reports, please visit https://www.fws.gov/program/national-wetlands-inventory/wetlands-status-and-trends. 

Wetlands Status and Trends reports provide impartial scientific estimates of the extent of wetland and deepwater habitats within the lower 48 states, as well as change in their area over time. Each report builds on the previous one, providing an invaluable historical perspective and increasing our understanding of landscape patterns and processes.

Data were collected using a survey-based approach covering 5,048 plots (four mi² each) randomly distributed across the lower 48 states. Using remotely sensed imagery, field visits, and on-screen digitizing techniques, the plots were examined for change between 2009 and 2019. Data quality was ensured through a multi-step process involving quality control/assurance by a series of regional and national experts, as well as field verification and automated logic checks.

Wetlands Status and Trends reports do not set policy. The information in this and past reports is used by natural resource managers and policymakers to make strategic decisions regarding the future of America’s wetlands. Within the Service and many other federal agencies, these reports are used to guide the funding, planning, and implementation of wetland restoration and enhancement, habitat assessments, strategic habitat conservation, and ecosystem management activities. These data have also been used in actions related to the implementation of the Endangered Species Act, including informing species listing determinations.

More than half of the nation’s wetlands (outside of Alaska and Hawaii) have been lost since European colonization. The report estimates that wetlands cover less than 6% of the lower 48 states, of which 95% are freshwater. Net wetland losses documented in this report (221,000 acres) for the years 2009 through 2019 continue this downward trend at a slower rate than in the mid-1900s.

The report indicates that wetland loss rates have increased by 50% since the previous 2004-2009 report and continue to disproportionally impact vegetated wetlands, like marshes and swamps. Vegetated wetlands are disappearing so quickly that 670,000 acres were lost between 2009 and 2019, an area approximately equal to the land area of Rhode Island. Loss of all wetlands but especially vegetated wetlands have ramifications for our wetland-dependent species and communities, including natural disaster resiliency and habitat for fish, shellfish, migratory birds, and about half of species listed under the Endangered Species Act.

There are many different types of wetlands, including vegetated and non-vegetated wetlands. Within the status and trends study, vegetated wetlands include wetlands with at least 30% coverage of emergent plants (e.g., erect, rooted, non-woody plants like grass), scrub-shrub (woody plants below 20 ft tall), and/or trees (woody plants above 20 feet tall). Vegetated wetlands include swamps and marshes. Non-vegetated wetlands have less than 30% plant cover and include ponds, mudflats, shoals, and bars.   

The main drivers of wetland loss have shifted through time. In the mid-1900s loss was mainly caused by drainage and fill associated with agriculture. During the 2009 through 2019 study period, loss was associated mainly with upland forested plantations, agriculture, and development. However, other drivers also likely contributed to the loss, including climate change climate change
Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.

Learn more about climate change and sea level rise.

Vegetated wetland decreases primarily occurred in the Southeast, Great Lakes, and Prairie Pothole regions. Decreases were particularly prevalent within the Southeast, including the coastal watersheds of Texas, Louisiana, Florida, the Carolinas, and the Delmarva Peninsula, as well as areas near the alluvial plains of the Mississippi and Mobile rivers.

The report was independently peer-reviewed by 10 wetland experts from two state and three federal agencies (U.S. Environmental Protection Agency, National Oceanic and Atmospheric Administration, and U.S. Geological Survey). Additionally, several federal and state agencies, as well as commercial and non-profit organizations, provided data analysis and technical resources that were critical to its completion. 

To achieve no net loss of all wetlands, including vegetated wetlands, a strategic update is needed on America’s approach to wetland conservation. The following strategies were developed to help remedy foundational wetland policy and management gaps and better support wetland conservation:

1. Achieve “No Net Loss” of wetlands and robust coordination with government and non-government partners.
2. Produce a contemporary NWI Geospatial Dataset and spatially explicit information on wetland function.
3. Develop and implement enhanced wetland conservation and management approaches based on a holistic review of current and past actions.
4. Commit to long-term adaptive conservation, management, and monitoring.

The no net loss goal for wetlands describes efforts to balance wetland loss with wetland reclamation, mitigation, and restoration so that total wetland acreage remains at least constant. The goal was first adopted in 1989 and has been the de facto federal policy ever since. The Service supports no net loss through its 2023 mitigation policy, Wetlands Action Plan (660 FW 1), and other policies. It is also the policy of many states. The Service’s Wetlands Status and Trends reports are the benchmark by which the federal government has tracked the no net loss goal.

Status and Trends findings of substantial wetland loss in the mid-1900s catalyzed the creation of wetland protection and restoration programs and policies, including the Swampbuster Provision of the 1985 Food Security Act (Public Law 99-198), U.S. Farm Bill wetland easement programs (e.g., Wetland Reserve Program), and the addition of wetland mitigation measures within the Clean Water Act (33 U.S.C.A. 1251 et seq.) permitting process. 

Although the Wetlands Status and Trends project was not designed to determine the effectiveness of any specific policy, the data have been used to measure progress toward the overarching federal “no net loss” wetlands goal. The reports continue to support strategic wetland policy and management today by driving collaboration and innovative planning between and amongst federal, Tribal, state, and local partners.

Wetlands provide food, shelter, nesting, and breeding grounds for many of our nation's species. About 50% of our nation's threatened and endangered species are wetland-dependent during part or all of their lifecycle. Wetlands provide stopover and wintering habitats for more than 4 billion birds from Canada as well as breeding habitats for nearly 5 billion migratory birds en route to the tropics. Wetlands also provide shelter, and vital nursery habitat for many commercially important species of fish and shellfish.

Wetlands have long provided food and building materials as well as recreational opportunities (e.g., hunting, fishing, kayaking, and bird watching) that benefit the health and well-being of tens of millions of Americans each year. Additionally, wetlands are an important cultural resource for communities, including the Gullah/Geechee people, and many Native American Tribes.

Wetlands are especially valued today because they help avoid or mitigate many of our most pressing environmental challenges, including increasing temperatures, rising sea levels, hurricanes and other severe storms, droughts and floods, wildfires, and the growing need for readily available clean water. The ecosystem services provided by wetlands are unmatched by any other habitat except coral reefs.

The substantial loss of wetlands documented by this study reduces the prosperity, health, and safety of communities through increased susceptibility of people and infrastructure to natural disasters like flood, drought, and wildfire, decreased food security, reduction in clean water, increased harmful algal blooms and related increases in toxins and oxygen-depleted “dead zones,” greater vulnerability to sea level rise and storms, and reduced recreational opportunities. The impacts of natural disasters, heightened by wetland loss, have been especially substantial.

Wetland loss also leads to declines in fish, wildlife, and plant populations, including rare, commercially important, and culturally valuable species.