Hurricanes and tropical storms bring more than flooding and pollution to affected areas—they also carry invasive plants and animals into new regions of the United States.
Since 2018, the U.S. Geological Survey has mapped the spread of more than 200 invasive species in the wakes of hurricanes. The maps first focused on the species spread by 2017’s major named storms, Harvey, Irma, Maria and Nate. That season saw 17 total named storms, ten of which were hurricanes. Intensifying hurricane seasons will only worsen the spread of invasive species around the U.S., Rebecca Renner reports for National Geographic.
“Our overarching goal for this as a tool...is to help with early detection and rapid response efforts,” said Matt Neilson, a USGS Wetland and Aquatic Research Center biologist, to Earther’s Maddie Stone in 2018. “In invasive species management circles [that’s] a key goal. The best time to manage a non-native species is at the start.”
The maps have an extensive most-wanted list. Zebra mussels, for example, traveled to the U.S. from the Black and Caspian seas and now plague the Great Lakes, Neilson told the Verge in 2019. The small mussels push out local mussel species and grow on hard human-made surfaces, affecting power plants’ cool water intakes, drinking water, irrigation systems and more. They’ve recently been spotted in the mid-Atlantic, per National Geographic.
An initial map of the effects of Hurricane Delta shows how the Cuban treefrog, which is covered in irritating secretions, has spread around New Orleans.
Invasive plants like water hyacinth, a floating plant native to South America, can grow densely on lakes and rivers and interferes with boating and fishing, per the Verge. Giant apple snails, which originally came to the U.S. through the aquarium trade, wreak havoc on aquatic crops like rice, per National Geographic, and spread a parasite called rat lungworm. In May, Texas Parks and Wildlife put out an advisory asking residents around the Houston area and the San Antonio River to report any sightings of the six-inch snail or its pink egg clusters, Mary Claire Patton reported for KSAT this May.
“There are two potential ways that a hurricane could move things around. The first would be storm surge. As the Hurricane’s coming, it’s pushing ocean water onto shore,” Neilson told the Verge. “The second would be through rainfall-associated flooding. We get lots of water getting dumped on the land, which raises the height of the water on those interior watersheds. Where it floods, water can spill from one watershed to the other.”
Like giant apple snails, many invasive species were first brought to the U.S. as part of the pet or hobby trade. Some scientists speculate that a 1992 hurricane caused the first mass release of Burmese pythons from a breeding facility into Florida’s Everglades, reports National Geographic. Now, the snakes dine on local species, including rabbits, deer and alligators.
The predators can grow to over ten feet long. Earlier this month, hunters working with the Python Elimination Program caught a 104-pound Burmese python that was 18-feet-and-nine-inches long, Florida Fish and Wildlife shared on Facebook. And in the last three years alone, programs have removed 5,000 pythons from the Everglades, Zachary Sampson reports for the Tampa Bay Times.
“Any potential increase in storm frequency or severity could increase the potential for species spread through the flooding,” said Neilson to the Verge.
Invasive species cost the U.S. about $120 billion per year, National Geographic reports. As climate change fuels more frequent, intense hurricanes, the range of invasive species will likely grow.