KILDARE WILDLIFE COLUMN: Duckweed - What lies beneath the surface

Common or Lesser Duckweed (Ros lachan as Gaeilge) is a native plant with tiny leaves that are shaped like a clover and can be found floating on the surface of ponds or canals in your local area.

Each leaf has a root hidden beneath the surface making what appears to be a single leaf an actual entire plant!

This plant can float solitary or group together to form lawns over the waters surface. As its name suggests it is a food source for Ducks offering an important protein source for these wetland birds.

It is also an important breeding area for the Common Frog who likes to hide their freshly laid spawn between these plants. Duckweed is even said to reduce algae blooms in ponds as it absorbs nitrogen from the water in turn limiting the growth of algae.

While this plant does produce a whitish flower I have never seen it flower at the Bog of Allen Nature Centre and according to what I have read about this wetland plant it is not uncommon for the plant to not produce a flower each year.

While Duckweed is a native plant and as described it does offer many benefits in smaller ponds the growth of Duckweed can become a problem.

I experienced this in a constructed pond at the Bog of Allen Nature Centre last summer. The warm weather encouraged this plant to multiply rapidly over the surface of the pond. The lawn of Duckweed that was formed limited light from reaching oxygenating plants that were submerged in the water and over a short space of time I noticed a decline in both the oxygenating plant and invertebrates living in the pond.

To resolve this issue I simply used a net to scoop about 90% of the duckweed from the pond surface. This allowed light to flood into the water encouraging the growth of the remaIning oxgenating plant and in time a return of the festwater invertebrates.

If you would like help identifying a wildlife species in your area or have taken a picture of wildlife that you would like to learn more about contact me at [email protected].