Recovery of Potamogeton pectinatus L. stands in a shallow eutrophic lake under extreme grazing pressure

  • Published source details Hilt S. (2006) Recovery of Potamogeton pectinatus L. stands in a shallow eutrophic lake under extreme grazing pressure. Hydrobiologia, 570, 95-99.


Action: Exclude wild vertebrates using physical barriers

A replicated, paired, controlled study in 2001 in a freshwater lake in Germany (Hilt 2006) found that fencing to exclude birds and/or fish sometimes increased the biomass and length of sago pondweed Potamogeton pectinatus shoots, but had no significant effect on shoot density. After two months, pondweed shoot biomass was greater in fully fenced plots (birds and fish excluded; 14–23 g/m2) than in open areas (1–5 g/m2). Partly fenced plots (only birds excluded) had a statistically similar shoot biomass (2–11 g/m2) to the open areas. Meanwhile, pondweed shoots were longer in both fully fenced plots (22–25 cm) and partly fenced plots (11–13 cm) than in open areas (6–7 cm). Pondweed shoot density did not significantly differ between treatments (fully fenced: 340–1,690; partly fenced: 190–1,400; open: 190–1,670 shoots/m2). Methods: In April 2001, sixteen 1-m2 exclosures (2 cm mesh) were established in sago pondweed stands in two shallow-water sites (0.5 m deep). In each site, four exclosures were fully fenced (mesh extending to sediment surface, excluding waterbirds and large fish) and four were partly fenced (25 cm gap between bottom of mesh and sediment surface, excluding birds but not fish). Vegetation was surveyed in June 2001: one sample/exclosure and four samples/site outside the exclosures. Biomass was dried before weighing. This study used two of the sites from Körner & Dugdale (2003).

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 18

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 Butterfly Conservation People trust for endangered species Vincet Wildlife Trust