Invasive Species Science at WARC

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This year, we recognize National Invasive Species Awareness Week on February 22 - 26 and May 15 - 22. Learn about USGS Wetland and Aquatic Research Center (WARC) invasive species science and the integral role our center plays in informing invasive species management strategies.

A Cuban treefrog on a palm frond

Cuban treefrogs are native to Cuba, the Bahamas, and the Cayman Islands, but are an invasive species in the U.S. They outcompete native frogs for food and habitat and can be a nuisance to homeowners as they clog plumbing and cause power outages when they seek shelter in utility boxes. WARC researchers use frog calls – or vocalizations made primarily by males interested in attracting a mate – to identify and track invasive frog species in the southeastern U.S. WARC researchers also perform visual encounter surveys and passively capture Cuban treefrogs to remove as many of the invasive anurans as possible.

What is an invasive species?

A species is considered invasive if it is introduced outside of its native range and causes harm to ecosystems, the economy, and/or human health.  

Nonnative, or nonindigenous, species are those organisms that have been introduced outside of their native range but are not yet known to cause harm. This means that while an invasive species is also non-native, not all non-native species are considered invasive.

Why are they an issue?

More than 6,500 of these harmful, non-native species cause more than 100 billion dollars in damage each year to the U.S. economy. Invasive species can severely impact native species and ecosystems. They often outcompete and prey upon native species, which can ultimately reduce biodiversity and alter an ecosystem’s food web. Aquatic invasive plant species, like hydrilla, can rapidly overtake a water body, blocking sunlight from reaching the plants and animals below and preventing navigation due to clogged waterways. Other aquatic invasive species, like the zebra mussel, damage infrastructure associated with power plants and other water systems, which results in increased maintenance costs.

What is WARC doing to address invasive species in the U.S.?

The USGS Ecosystems Mission Area’s Invasive Species Program provides the research, management tools, and decision support needed to meet the science needs of resource managers to reduce or eliminate the threat of invasive species and wildlife disease. At WARC, we work closely with our local, state, and federal partners to provide the science they need to address the critical invasive species issues facing the southeastern U.S. Our center leads research and monitoring programs and implements innovative technologies to help control or eradicate invasive species.

Monitoring the Introduction and Spread of Aquatic Invasive Species

The USGS WARC houses the Nonindigenous Aquatic Species (NAS) database, which tracks the distribution of introduced aquatic organisms across the United States. The publicly accessible information repository monitors, records, and analyzes reported sightings for >1,300 species like lionfish, zebra mussels, and hydrilla. The database contains observations from as early as 1800, derived from many sources, including scientific literature; federal, state, and local natural resource monitoring programs; museum collections; news agencies; and direct submission through on-line reporting forms from citizen scientists. Subscribers to NAS alerts emails can be informed when a new non-native species has been reported in their area as part of a national early detection and rapid response (EDRR) system. The NAS program also uses the data to help forecast where these species may go next. One such tool developed by members of the NAS team, along with WARC’s Advanced Application Team, is the NAS Flood and Storm Tracker (FaST) maps, which help natural resource managers track and manage the potential spread of non-native aquatic species into new water bodies due to storm-related flooding. The FaST maps are easily accessible, informative, and provide the most up-to-date information to resource managers about potential new invasions, acting as an additional tool for EDRR systems.

Hurricane Isaias (2020) Flood and Storm Tracker (FaST) Map for Zebra Mussels

Hurricane Isaias (2020) Flood and Storm Tracker (FaST) Map for Zebra Mussels

Flooding related to hurricanes and tropical storms can help spread non-native aquatic plants and animals, like zebra mussels, into new waterbodies. Once established, they have the potential to cause infrastructural damage (e.g., block pipes) and upset aquatic food webs by preying on native species. The USGS Nonindigenous Aquatic Species (NAS) program, which houses records for non-native aquatic species across the nation, creates Flood and Storm Tracker (FaST) maps which help managers track and manage the potential spread of non-native aquatic species into new water bodies via storm-related flooding.

For more information, please visit: https://nas.er.usgs.gov/viewer/Flooding/

CSI: Python-Style

Three pythons well camoflaged

How do you detect a cryptic species? A droplet digital PCR platform can detect even a single piece of genetic material, if present in an environmental sample. This information can be used to accurately estimate the likelihood that the species of interest is present in the environment.

Crime shows/movies/podcasts often tell the story of a criminal who thought they got away with it, only to be brought down by a forensic investigator who discovered a small piece of genetic material at the crime scene belonging to said criminal. Just like a crime scene, ecosystems often require researchers to zoom in to the microscopic, hard-to-spot clues to better understand the full picture. Wildlife, like humans, shed genetic material, in the form of excrement, hair, saliva, mucus, skin cells, etc., as they move. The organism’s genetic material is shed into the surrounding environment (i.e., soil, water, snow, air) and referred to as environmental DNA (eDNA). At WARC, researchers are using eDNA techniques to help detect hard-to-find invasive species, like the Burmese python. The cryptic constrictor camouflages into the surrounding Everglades ecosystem, which has made it difficult to find and eradicate. By testing environmental samples, WARC scientists can identify python eDNA in an area whether or not a snake has actually been observed. With improved detection capabilities comes the increased capacity to effectively delineate range limits and better assess the status, distribution, and habitat requirements for pythons and other secretive or rare invasive species.

 

Image: Close-Up of a Radio Transmitter on an Invasive Burmese Python

This close-up is of the radio-transmitter on a 16 1/2-foot python. The snake, being removed from the wild by USGS and NPS personnel, was re-captured in a thicket in Everglades National Park in April 2012. After its first capture, the snake was equipped with a radio-transmitter and an accelerometer as part of one of the Burmese python projects led by USGS to learn more about the biology of the species to help in efforts to develop better control methods.

Read more on how WARC and partners use telemetry studies to better understand python movement rates and habitat use patterns across South Florida.

EDRR – Early Detection and Rapid Response

The first confirmed lionfish sighting was reported in 1985 off the coast of Dania Beach, Florida. Though native to the Indo-Pacific region, a single lionfish didn’t raise many alarms. But then another lionfish was reported in 1990. And then another one in 1992. And then a few more in 1995. By the early 2000s, lionfish had taken over coastal waters in the southeastern U.S. Lionfish have invaded Atlantic coastal waters from New York to the Florida Keys, the Caribbean Sea, and the Gulf of Mexico with unprecedented speed and now serve as a case study demonstrating why early detection and rapid response efforts (also known as EDRR) are critical. A single non-native fish might not immediately pose a problem, but if it isn’t removed, it could reproduce and quickly take over the new habitat. Once a population has established and begins reproducing, it is difficult to manage or eradicate. At WARC, researchers work with partners to quickly address non-native marine fish sightings in Florida’s coastal waters, removing the fish whenever possible, to help prevent potential future invasions.

Blotched foxface rabbitfish (Siganus unimaculatus)

A citizen scientist spotted a popular aquarium fish, the blotched foxface, a species of rabbitfish, while scuba diving offshore of Dania Beach, Florida. Within 24 hours of receiving the sighting report, a coordinated effort by Reef Environmental Education Foundation (REEF) and the U.S. Geological Survey led to the live capture of the fish. Though its native to the West Pacific Ocean, this individual blotched foxface now calls the Patricia and Phillip Frost Museum of Science in Miami, Florida, home, where it is on display as part of an education exhibit on non-native marine fishes.

(Credit: James Fatherree, Hillsborough Community College.)