Louisiana’s coastal wetlands, known for their subtropical climate, rarely experience snow or extreme cold. However, a recent winter storm in early 2025 brought an unusual blanket of snow to the region, prompting concerns about its impact on the state’s delicate coastal ecosystems. While some wildlife and plant species may have been affected, experts assured that the wetlands themselves were unlikely to suffer significant damage, as per this article from The Advocate.

One of the most immediate consequences of the cold snap was the reported fish kills along Louisiana’s coastal wetlands. Certain fish species, particularly those not native to the state, struggled to survive the sudden temperature drop. The rapid decline in water temperature appeared to have been the primary cause, as fish are highly sensitive to abrupt environmental changes. While some species faced challenges, others demonstrated resilience. Alligators, for instance, were largely unaffected by the cold. According to Chris Schieble, deputy assistant secretary of fisheries at the Louisiana Department of Wildlife and Fisheries, alligators had already entered a hibernation-like state known as brumation. They remained buried in their mounds, conserving energy and avoiding exposure to the frigid temperatures.

Similarly, native birds to our coastal wetlands may have experienced initial confusion due to the unusual conditions, but experts believed they would adapt without long-term harm. Other cold-hardy swamp creatures, such as river otters, were also expected to remain largely unaffected.

The snow-covered landscape presented an unusual sight for Louisianans, with palmettos, bald cypress trees, and live oaks weighed down by frost and icicles. Though some plants might suffer damage, Robert Twilley, a coastal sciences professor at LSU, expressed confidence that most native plant populations would recover quickly.

One species of concern, however, was the black mangrove. These subtropical plants, which have expanded across Louisiana’s coastline since the 1980s due to warming temperatures, are highly sensitive to frost. Twilley noted that while some black mangroves would likely die, he had been surprised in the past at their ability to recover.

Andrew Ferris, coordinator of the native plants program at the Coalition to Restore Coastal Louisiana, expected some mangrove losses but reassured that other native species would fare well. He visited a site in St. Bernard Parish where 2,000 bald cypress and water tupelo trees had been planted for coastal reinforcement. Since these trees are native to South Louisiana, they were well adapted to withstand cold snaps and occasional snowfall.

While native species demonstrated resilience, the freezing temperatures might have benefited Louisiana’s wetlands in another way—by reducing invasive species populations. Nutria, the destructive rodents native to South America, struggled in the cold, with many perishing due to their inability to adapt to sudden temperature drops. Schieble noted that these animals, which are notorious for devouring wetland vegetation, were unlikely to survive prolonged exposure to freezing weather.

Other invasive species in the states’ coastal wetlands, including water hyacinth and giant salvinia—both of which overtake Louisiana’s waterways during warmer months—were also expected to suffer significant die-offs. Since these plants are not cold-tolerant, experts predicted that the frigid weather would provide a temporary reprieve from their rapid spread.

However, not all coastal wetlands invasive species were impacted. Feral hogs, known for their ability to destroy vegetation and disrupt wetland ecosystems, were expected to survive. Schieble explained that their thick winter coats allowed them to withstand cold temperatures, making them one of the few unwelcome species that would persist despite the harsh conditions.

Overall, Louisiana’s coastal wetlands and wildlife proved resilient in the face of this rare cold event. While certain species, particularly non-native plants and animals, faced temporary losses, the foundational elements of the ecosystem remained intact. Scientists and conservationists will continue monitoring the effects of the cold spell, particularly on fish populations and the survival of black mangroves. However, for the most part, Louisiana’s wetlands emerged from the winter storm with their long-term stability unshaken.

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