Genetic characterization of introduced European frogbit and water soldier (Hydrocharis morsus-ranae and Stratiotes aloides) to support management and biological control development | W81EWF 23 SOI 0017

Frequently Asked Questions (FAQs)

What is the main purpose of this funding opportunity?

This opportunity funds research that helps improve long-term management options for two invasive aquatic plants in North America: European frogbit (Hydrocharis morsus-ranae) and water soldier (Stratiotes aloides). The project focus is on generating the genetic and origin information needed to guide future classical biological control efforts in a more targeted and evidence-based way.

Which invasive species are covered?

The opportunity targets two aquatic invasive plants:

• European frogbit (Hydrocharis morsus-ranae)
• Water soldier (Stratiotes aloides)

Why are these aquatic plants a concern?

The notice emphasizes that aquatic invasive plants can create major, recurring costs in the United States because they often require ongoing control and mitigation. It also notes that common management tools (such as herbicides and mechanical removal) can be expensive at large scales and may risk harming native plant communities.

What impacts does European frogbit have?

European frogbit is described as particularly damaging because it forms dense, free-floating mats that:

• Interfere with boating and other water traffic
• Slow water movement
• Crowd out native vegetation
• Contribute to low-oxygen (hypoxic) conditions that degrade aquatic habitat
• Reduce recreational value for activities such as swimming and fishing

What is the invasion history of European frogbit in North America?

The opportunity describes European frogbit as having escaped from a botanical garden in Ottawa in the 1930s, then spreading across parts of the Great Lakes region and into U.S. states including Vermont and Washington.

What management approaches have been tried for European frogbit, and why are they considered limited?

Prior biocontrol attempts have mainly involved generalist herbivores (for example, native snails and grass carp). The notice indicates these efforts have produced limited control, which supports the rationale for exploring classical biological control using specialized natural enemies from the plant's native range.

Are there already potential biological control candidates for European frogbit?

Yes. The notice states that several candidate natural enemies have been identified in Europe and adjacent regions. The opportunity frames the current need as better targeting and selection, supported by a stronger understanding of the genetics and origins of the invasive populations.

Why is water soldier considered high concern even though it has a smaller known footprint?

Water soldier is described as an emerging invader with a relatively small confirmed distribution so far (reported primarily from the Trent River in Ontario after detection in 2008). Despite this, it is treated as high concern because its impacts are expected to resemble those of European frogbit. The notice also highlights an added public safety and nuisance issue: its sharp, serrated leaves can cut people who come into contact with it.

Where has water soldier been reported in North America according to the notice?

The opportunity reports water soldier primarily from the Trent River in Ontario, following detection in 2008.

How does the opportunity frame biological control as a management solution?

The announcement presents classical biological control as a potentially more sustainable and cost-effective approach than repeated large-scale herbicide treatments or mechanical removal. It also stresses that successful biocontrol depends heavily on understanding the genetics and source origins of invasive populations before selecting and pursuing agents.

What is "classical biological control" in the context of this opportunity?

In this notice, classical biological control refers to identifying specialized natural enemies (such as damaging insects and pathogens) from the invasive plant's native range and evaluating them as potential control agents. The process described includes focused field exploration in the native range, followed by importation of prioritized candidates into quarantine for research and host-specificity testing before any further steps toward release.

Why does the opportunity emphasize genetics before selecting biocontrol agents?

The notice identifies two key genetic questions that should be addressed early:

• How much genetic diversity exists within the introduced populations?
• Which regions in the native range the introduced populations came from?

This matters because biocontrol agents can be locally adapted to particular plant genotypes. If introduced plants originated from a specific source region, natural enemies collected from that same region are expected to be more likely to match and perform well on the invasive genotypes present in North America.

What does "molecular matching" mean here?

The notice describes using molecular matching to identify likely source areas in the native range and to map genetic structure across the invaded range. The goal is to make later biocontrol exploration more efficient and more likely to succeed by focusing surveys and agent collection in the most relevant regions and on the most relevant plant genotypes.

How does the opportunity suggest planning surveys for biocontrol agents?

The announcement indicates that effective exploration is not a one-time visit. It states that repeated surveys throughout the year are needed to capture phenology and seasonal dynamics and to identify the most impactful natural enemies.

Why does the notice suggest considering European frogbit and water soldier together in biocontrol planning?

The opportunity notes that water soldier often occurs in the same native-range habitats as European frogbit and that the two species are closely related (both in the Hydrocharitaceae). Because of this, it suggests surveys for natural enemies and biocontrol planning should consider both species together, since overlapping enemy communities or similar approaches may be relevant.

What does the notice say about risk and potential spread in the United States?

The opportunity cites USDA-APHIS weed risk assessments indicating both plants have a high likelihood of becoming serious invaders, with predicted potential distributions spanning much of the eastern half of the contiguous United States.

What types of organisms does the opportunity mention as potential biocontrol agents?

The announcement specifically references damaging insects and pathogens as the kinds of candidate agents that could be identified through field exploration and then prioritized for quarantine research and host-specificity testing.

What happens after candidate biocontrol agents are identified, according to the notice?

After candidates are identified, the notice describes prioritizing and importing them into quarantine for research on basic biology and, critically, host-specificity testing to ensure safety for non-target species before any further steps toward release.

Who is offering this grant opportunity?

This is a discretionary funding opportunity offered by the Department of Defense through the U.S. Army Engineer Research and Development Center (ERDC).

What type of funding instrument is expected?

The funding instrument is a cooperative agreement.

How many awards are anticipated?

The opportunity indicates an anticipated single award.

What is the maximum award amount?

The award ceiling is $100,000.

What is the opportunity number and CFDA listing?

The opportunity number is W81EWF 23 SOI 0017, and it falls under CFDA 12.630.

When was the opportunity posted and what was the original closing date?

It was originally posted on June 2, 2023, with an original closing date of August 2, 2023.

Who is eligible to apply?

Eligible applicants are listed broadly as "Others," with additional eligibility details referenced in the full opportunity materials.

What is the project positioned as within the larger biocontrol pipeline?

The notice frames the proposed work as a stepping-stone that makes later biocontrol exploration more efficient and more likely to succeed. By identifying genetic diversity and native-range sources first, later surveys can be targeted to the most relevant regions and plant genotypes, improving the odds of finding effective, well-matched natural enemies.