The high winds, heavy rains and storm tides caused by hurricanes and tropical storms can rapidly change the landscape of an area affected by a storm. Hurricane-related flooding can also result in a slow transformation of ecosystems found on land and in water, as floodwaters can carry invasive wildlife and plant species into new regions, accelerating their spread.

When invasive species spread into new areas, there can be environmental, economic, and human health effects. Due to the importance of the issue, farmers, ranchers, businesses, and Tribal and government officials are working to mitigate the threats these invaders pose. The U.S. Geological Survey aids these efforts by creating Flood and Storm Tracker maps that identify where non-native species may have been carried during a major flood event. These maps provide land managers information they can use to help focus their efforts in areas where invasives likely spread.

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The scientists who oversee the USGS Nonindigenous Aquatic Species database–the national repository for confirmed sightings of nonnative species found in water across the U.S.–use data on water levels, water flow and storm tide heights to identify places where waterways may have merged during flooding. They combine that information with established local nonindigenous plant and animal populations to identify aquatic species that had the potential to spread and locations where they may have expanded.

USGS experts have created more than a dozen Flood and Storm Tracker maps since the first one was produced in 2017 after Hurricane Harvey made landfall in Texas. The maps are useful tools for land managers as they work to mitigate the potential spread of non-native species. Each map focuses on local species from the almost 1,400 various plants and animals included in the database. Past maps created by the USGS have forecast the spread of many notorious invasive species, such as giant apple snails, African jewel fish, zebra mussels and water hyacinth. The maps can be viewed here.

Come back next week to learn how the USGS measures the vast extent of flooding that hurricanes and tropical storms can cause and how this knowledge helps communities better prepare for future floods.

*Editor’s note: The photo at the top of the story shows zebra mussels, which are an invasive species that can easily spread through floodwaters. Photo by Amy Benson, USGS.

In case you missed them, here are links to the other posts in this series:

• Introduction to a Six-Part Series Highlighting USGS Hurricane Science
• Storm Tide Poses One of the Most Serious Hurricane Threats to People and Infrastructure
• Changes to the Coastline Can Affect Where, and How Severely, Flooding Occurs
• Hurricanes may pose a threat to people along the coasts and far inland
• Determining how high flood waters reached helps communities prepare for future floods
• Maps and Imagery for Hurricane Response