The Wetland Conservation Diary (UK): Macrophytes of the Malltraeth marsh and a few starling too!

Bangor universities botanic garden at Treborth was the scene for a day of getting to grips with wetland biodiversity with a wetland plant ID course. A visit to Malltraeth marsh rounded off the evening!

The constrcuted pond at treborth bonanic garden

A view over Malltraeth marsh

Treborth Botanic garden

Bangor universities botanic garden at Treborth was the scene for a day of getting to grips with wetland biodiversity with a wetland plant ID course. Treborth is a special place and provides a home range for a range of native species in its grounds as well as the usual exotic plant species found in a botanic garden. On route to the wildlife pond we were greeted by the deep croaking call of a pair of ravens which in turn set off an alarming frenzy by the passerines.

The wildlife pond, located in an area of wet meadow within an orchard in the gardens grounds was created as a wildlife and education resource. The design provides a topographic gradient of one meter deep open water to waterlogged overflowing margins suited to host a wide range of emergent and submerged and floating macrophytes. The gardens also support two smaller dipping ponds is for children to experience pond life.

The pond was species rich and was brimming with life, albeit most the plants were going into winter mode by translocating nutrients into their roots to conserve energy. Most plants here were relocated form Malltraeth marsh were we spent the early evening watching upto fourty thousand starlings come into roost in the Phragmites reedbeds. In the pond we encountered Chara species, a filamentous green alga which is a pioneer species and usually indicates unpolluted water with a pH of between 6 and 9, some can tolerate high salinity. This group of green algae appear as a green slime, are evergreen and can have a foul smell.

Duckweed also occurs in the pond, this plant can have a great impact onvthe rest of its plant competitors. Three species of duckweed were found in the pond; Spirodeela polyrhia (greater duckweed) has many roots on each leaf and the underleaf is purple. Lemna trisulca (Ivy- leaved duckweed) has one root for the whole system and floats just below the water surface. Each translucent leaf has three leaflets with pointed tips and a stalk connecting it to the next leaf. Lemna minor (Common duckweed) have leaves which are yellow-green with an underside lighter than the topside.

Malltraeth Marsh

Malltraeth marsh (area and altitude) is a riverine freshwater marsh, south-west of the Isle of Anglesey in North Wales. It is owned and managed by the RSPB primarily for birds (Bittern and Lapwing). The site was greatly affected by coal mining in the 19^th centaury and parts of the ground have subsided. The marsh is influenced by the river Cefni which was heavily canalised in the 1800’s. The Cefni embankments and the Malltraeth Cob have influenced the marsh to an extent where it no longer receives saltwater from the estuary inflow. It would have historically been a saltmarsh and supported obligate halophytes. Around this time, most of the marshland was reclaimed and drained for agricultural purposes with perpendicular agricultural ditches, draining into the two large drainage ditches running parallel to the straightened river Cefni.

One of the drainage ditches running parallel to the river Cefni, the ditched were originally lined with impermeable clay to maintain water level, but this was accidentally removed when cleared of sediment. It is suggested that

clearing out the ditch on a 5 to 10 year cycle will stop sedimentation and not disturb the plant communities that develop in the ditch. The ditch was created with stepped sides to created a anchoring point for emergent plants.

Phragmites australis (common reed) bed. The reeds harden in winter enough to support a roosting bird such as a starling. They have a rhobust rhizome and a characteristic white ring of hairs between the sheath and the blade. these tall reeds are important for birds to sit on over the water and keep out of reach of mammalian predators such as the Fox.