Is roach herbivory preventing re-colonization of submerged macrophytes in a shallow lake?

  • Published source details Körner S. & Dugdale T. (2003) Is roach herbivory preventing re-colonization of submerged macrophytes in a shallow lake?. Hydrobiologia, 506, 497-501.


Action: Exclude wild vertebrates using physical barriers

A replicated, paired, controlled study in 2001 in a lake in Germany (Korner & Dugdale 2006) found that fencing to exclude birds and fish typically increased above-ground biomass of sago pondweed Potamogeton pectinatus, but that fencing to exclude birds only had no significant effect. After two months, fully fenced plots (birds and fish excluded) contained more pondweed biomass than open areas in three of four comparisons (for which fenced: 14–23 g/m2; open: 1–5 g/m2; other comparison no significant difference). Meanwhile, pondweed biomass in partly fenced plots (only birds excluded) was statistically similar to open areas in four of four comparisons (fenced: 2–11 g/m2; open: 1–7 g/m2). Methods: In April 2001, thirty-two 1-m2 exclosures (2 cm mesh) were established in sago pondweed stands across four shallow-water sites (0.5 m deep). Each site had four fully fenced exclosures (mesh extending to sediment surface, excluding waterbirds and large fish) and four partly fenced exclosures (25 cm gap between bottom of mesh and sediment surface, excluding birds but not fish). Biomass was collected in June 2001: one sample/exclosure and four samples/site outside the exclosures. Biomass was dried before weighing. Two sites in this study were also used in Hilt 2006.

Output references
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