Reedbed

Reedbeds are dense stands of common reed that occur predominantly in river floodplains and low-lying coastal plains. They are a nationally scarce habitat supporting several rare dependent species of birds and invertebrates, such as the bittern and reed leopard moth.

Reedbed design

Reedbeds can be created anywhere there is:

Sufficient, reliable water supply to maintain flow, and up to 300 mm of depth in spring.
Level ground or very shallow gradient.
An available, vigorous reed source.
Access for management.

Larger reedbeds tend to support more species. Some species require extensive reedbeds, e.g. the bittern and marsh harrier. Value is added if it is part of a larger complex of swamp, open water and wet woodland as all have their associated species. The reedbed-to-open water edge is very productive as aquatic life can penetrate into the reedbed. These areas support more birds than the equivalent area just covered in reed.

The ability to vary water levels is important. Adequate water supply is needed during summer, flooding in spring is necessary to control competing terrestrial weed species, and dry periods allow access to manage and encourages oxidation of litter to make nutrients available and prolonging the reedbed’s life.

A subtly undulating landform with a variety of water depths across the reedbed is ideal. The soil required to create the unevenness is often available from the construction of ditches and excavation of meres.

Where commercial harvesting is planned, more even topography is needed, otherwise reed quality will vary and it will be difficult to harvest.

Management is required to prevent succession. This can be achieved through sustainable commercial cutting for reed thatching or bio-fuel. This should be considered in the design, for example to ensure machinery access if necessary.

Bed preparation

The extent of bed preparation depends on the establishment technique, soil type and the condition of the bed.

Reed can be established on most soil types, though clays and silts are better. Oxidised peat may need pre-flooding and drawdown to de-acidify it pre-planting.

Bed preparation involves controlling competing vegetation. Strip existing vegetation and litter during land-forming. Alternatively, control with herbicides, rotovation, ploughing or flooding. Note that rotovation and ploughing can expose weed seedbanks and favour rush invasion. Reed should be introduced as soon as water levels are suitable.

Fine scale control of water levels is needed during early establishment - low enough to promote establishment, and high enough to discourage competition from other plants:

Young reed is vulnerable to both dehydration and drowning.
Keep soil damp until the reed shoots, then raise water levels, ensuring that the top third of the plants are above the surface.
Reducing the extent of open water could restrict damage by Coots and geese.

Reed establishment

It is not necessary to plant the whole site; creating nuclei of reeds encourages spread into appropriately managed areas. Expansion rates are affected by temperature and water depth, and vary from 1 to 10 m year-1 or faster in exceptional circumstances.

Sowing seed

Hand sowing is the only practical option. Aerial seeding is very expensive.

The following factors need to be considered:

Seed viability should be tested before sowing.
Sowing should take place in still wind conditions.
Soil should be saturated but not flooded.
Bed should be flat and free of vegetation.
Sowing should take place in May-June, when daytime temperatures range from 10-25°C and nights are frost free.
fragments of the seed head should be pressed gently into the seedbed to ensure good contact. Rollers are rarely suitable; instead compression boards or trampling should be used.

Sow at densities between 10-125 viable seeds m-2 on bare, wet soil. Germination takes 3-4 days in good conditions. Keep the seedbed wet without over-topping seedlings. Once shoots reach 100-200 mm, the bed can be flooded to 50 mm.

Reed will not establish from seed in the UK, from Northumberland northwards, as summer temperatures are too low.

Planting seedlings

This is the most successful method of establishing reedbed as seedlings can compete and survive adverse weather. Nursery-grown material is expensive so it may be more cost-effective to grow your own.

Planting out by hand is slow; densities of 4 m-2 take ca 540 person hours ha-1, but mechanisation is only at an experimental stage. Plant in June; as early as possible after the last frosts but before competitors develop. Water levels should be at or just above the soil surface.

Water levels can be used to suppress weeds. Seedlings <1 year old tolerate water levels up to 200 mm over the shoots. Reedmace and rushes can be difficult to remove, but reed will usually out-compete them eventually, however areas of mixed vegetation are beneficial in the meanwhile.

Spreading soil containing rhizomes

This involves transferring the top 300-500 mm of rhizome-rich soil from an existing reedbed to a prepared recipient site. Such material is often excavated during maintenance of drainage channels or during bed lowering.

The following points should be considered:

Spread soil at least 250 mm deep and flood to 200 mm.
Do not let the soil dry out.
Minimal soil manipulation will reduce rhizome damage, and do not store the material for long periods.
Excavate and spread the material in the winter: November to February.
Dig to just below the rhizome level; the depth varies according to the site.
It may be necessary to pre-excavate the recipient site to achieve desired water levels.

This, and turf transplanting (see below), will import litter and soil invertebrates, and other plants to the site, accelerating colonisation.

2,500 m3 of material is required per hectare and transportation costs high, so, spread loads at intervals, e.g. 100 ha-1.

Turf transplant

Digging out complete rhizome mats is very successful- it minimises damage and reduces the volume of material to transport.

Space the turfs depending on their size and the desired rate of spread of the reed. Generally, the following points are important:

Larger turfs contain more undamaged material and establish more quickly.
Water levels can fluctuate more – from just below the surface to up to 500 mm deep where the turfs have long, intact reed stems attached.
Bed preparation is less critical, providing flooding is immediate to suppress competition.
Do not stack turfs in transit or storage; this damages aerial stems which supply oxygen to the rhizomes.
Carry out work in winter, during drawdown of water levels.

Management during establishment of reedbeds

Keep establishing reedbed free from competition and from grazing in the first year. New reed is eaten by a variety of grazing animals, including geese, coots, deer, rabbits and livestock, which seriously inhibit reed growth/ expansion. Some form of fencing would be essential: orange plastic netting with tape stretched over the enclosure has been successful at some sites, but needs to be combined with regular human disturbance to keep wildlife out.

Longer-term management

Rotational cutting and removal of reed in the winter is the commonest method of management, it will:

Reduce the rate of litter accumulation.
Stimulate the production of new buds.
Provide temporary open, wet habitat.
Control reed encroachment into other habitats.

Other management techniques include summer cutting, grazing and burning ensuring that only a proportion is managed each year to conserve invertebrate population. Old reedbeds may require lowering as litter levels build up.

Relevant case study

Hanson-RSPB wetland project, Needingworth

The information set out within this advisory sheet in no way constitutes legal or regulatory advice and is based on circumstances and facts as they existed at the time Nature After Minerals compiled this document. Should there be a change in circumstances or facts, then this may adversely affect any recommendations, opinions or findings contained within this document