Study

Filamentous algal control using barley straw

Summary

Action: Use barley straw to control algae

A controlled study in 1990–1993 in a canal in Ireland (Caffrey & Monahan 1999) reported that adding barley straw to control filamentous algae facilitated growth of whorled watermilfoil Myriophyllum verticillatum. After 18 months, “localised stands” of watermilfoil appeared in a stretch of the canal treated with barley straw. After 33 months, watermilfoil reached 25% cover and 85 g/m2 biomass in the treated stretch. No watermilfoil was present in an upstream, untreated stretch. In all 12 comparisons between 6 and 33 months after first adding barley straw, the treated stretch contained significantly less filamentous algae (0–14 g/m2) than the untreated stretch (24–120 g/m2). Methods: The study used two adjacent 1-km stretches of a canal susceptible to nuisance growth of filamentous algae. Barley straw (loose floating bales, equivalent to 10 g/m3) was added to the downstream stretch in October 1990. Further straw was added every 4–7 months until February 1993. The upstream stretch received no barley straw. Biomass (above- and below-ground) was sampled with a plastic “stovepipe” every 2–3 months (except winter), from October 1990 to July 1993. It was dried before weighing.

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 21

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 ProgrammeRed List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Mauritian Wildlife Supporting Conservation Leaders
Sustainability Dashboard National Biodiversity Network Frog Life The international journey of Conservation - Oryx Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered species Vincet Wildlife Trust