Less than an hour outside of New Orleans lies an iconic landscape filled with all the things one may think of when picturing Louisiana: bald cypress trees draped in delicate Spanish moss, alligators roaming the waters with snouts and eyes barely visible, and large-winged herons and egrets hunting along the flooded forest floor. Maurepas Swamp, one of the largest remaining swamp forests in the United States, provides a critical link for birds like Prothonotary Warblers migrating between their nesting grounds in North America and their wintering grounds in Central and South America. This treasured swamp, and the birds that rely on it, are currently in decline, and a new project breaking ground today aims to save them.
Like most of Louisiana’s coastal wetlands over the past 150 years, Maurepas Swamp has been deteriorating due to a number of threats. Back in the early 1900s, it was clear-cut for timber, but it started to bounce back in the 1920s. Unfortunately, things took a turn for the worse when levees were built along the Mississippi River, cutting the swamp off from the fresh water, nutrients, and sediment it needed to thrive. This isolation, along with stagnant waters and rising salinities in the Pontchartrain Basin in the decades that the Mississippi River Gulf Outlet was open, put the swamp in a steep decline. Now, trees are dying, and there aren’t enough young ones growing to replace them. Maurepas serves as a critical buffer for surrounding communities from storms and flooding—without it, major cities like New Orleans and Baton Rouge would face even greater challenges as climate change increases those threats. It’s a swamp in serious need of a comeback.
Researchers at Audubon Delta, Southeastern Louisiana University, and Louisiana State University spent over 20 years examining the health of the Maurepas Swamp and the impact of these disruptions on the vulnerable ecosystem’s hydrology—the flow of water in and out of the swamp. They tracked bird populations and even looked at an unexpected indicator—caterpillars—to get the full picture of what’s happening in this unique swamp.
Caterpillar outbreaks on the two dominant tree species in Maurepas Swamp, bald cypress and water tupelo, can defoliate large expanses of forest in some years. Although this may seem alarming, these caterpillars only have one generation per year, and the trees quickly regrow leaves after the outbreak is finished by late summer. Importantly, these caterpillars are also not newly introduced—in fact, their emergences coincide with the nest season for food for insectivorous swamp birds like the Prothonotary Warbler, Northern Parula, and Yellow-throated Warbler, and therefore play an important role in maintaining a healthy ecosystem.
Audubon’s research has shown that over the last two decades, bald cypress leafroller caterpillar outbreaks have become increasingly rare, and as a result, swamp forest songbird populations, like the Prothonotary Warbler, have declined by about half. These caterpillars depend on healthy cypress trees to thrive, but the entire swamp ecosystem is increasingly out of balance, largely because of the lack of freshwater flow. To prevent further collapse of the swamp, we need to restore the swamp’s food web, and to do that, we need to restore its connection to fresh water, especially from the Mississippi River.
Luckily, there’s a solution on the way. The River Reintroduction to Maurepas Swamp project is set to bring a much-needed boost of freshwater, nutrients, and sediment to the wetlands, giving the swamp the lift it needs to thrive for the long haul and become more resilient than ever.
This novel diversion project is set to reconnect one of the largest forested wetland complexes in the U.S. with the mighty Mississippi River, preventing further wetland loss and habitat damage. In the face of climate change and sea-level rise, this plan will protect over 45,000 acres, boosting a natural wetland buffer that helps reduce storm surges for communities all the way from Greater Baton Rouge to Greater New Orleans. It’s a game-changer for both the environment and the people who depend on it.
Today, the State of Louisiana breaks ground on this river diversion project with support from several federal agencies, nonprofits, and community partners. This project is a key piece of Louisiana’s Coastal Master Plan, and it was funded in part by the BP Deepwater Horizon oil spill settlement. Audubon is proud see the construction of this project begin after studying and advocating for the swamp for many years as a member of the Mississippi River Delta Coalition.
With the River Reintroduction project on the ground, Maurepas Swamp will keep providing a perfect home for the Prothonotary Warbler and a whole host of other amazing wildlife, from wading birds and migratory birds to bald eagles, alligators, and many more. Another key piece of Louisiana’s coast is poised for a much-needed revival, ensuring that this vital ecosystem continues to thrive for generations to come, supporting both its incredible wildlife and the communities that rely on its protection.
