Whole lake fluridone treatments for selective control of Eurasian watermilfoil: II. Impacts on submersed plant communities

  • Published source details Madsen J.D., Getsinger K.D., Stewart R.M. & Owens C.S. (2002) Whole lake fluridone treatments for selective control of Eurasian watermilfoil: II. Impacts on submersed plant communities. Lake and Reservoir Management, 18, 191-200.


Action: Use herbicide to control problematic plants

A replicated, controlled, before-and-after study in 1997–1998 of eight freshwater lakes invaded by Eurasian watermilfoil Myriophyllum spicatum in Michigan, USA (Madsen et al. 2002) found that applying herbicide had no clear effect the overall richness or abundance of submerged plants, despite reducing watermilfoil abundance. Comparing data from just before and 3–15 months after applying herbicide, watermilfoil frequency (percentage of survey points where present) declined in 9 of 12 comparisons in treated lakes (before: 39–73%; after: 0–13%) but increased or did not significantly change in 12 of 12 comparisons in untreated lakes (before: 30–43%; after: 33–73%). However, treated and untreated lakes experienced similar changes in submerged macrophyte richness and abundance. For example, total richness increased in 12 of 12 comparisons in both treated lakes (before: 1.1–2.3; after: 2.1–3.4 species/site) and untreated lakes (before: 1.2–1.6; after: 1.5–4.1 species/site). Total frequency increased in 4 of 12 comparisons in both treated lakes (before: 72–89%; after: 82–100%) and untreated lakes (before: 51–94%; after: 87–100%), with no significant change in the other comparisons. Results were similar for native species (see original paper for data). Methods: In May–June 1997, herbicide (fluoridone) was applied to four lakes. The aim was to maintain 5 µg/L of fluoridone in the upper 3 m of water, for 60 days. Submerged macrophytes were surveyed in a grid of points across the four treated lakes and four nearby untreated lakes, before intervention (May 1997) and for 15 months after (August 1997, May 1998 and August 1998).

Output references
What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 20

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered speciesVincet Wildlife Trust