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Phragmites australis is a common plant of damp and wet ground, which grows in water of normally less than 1m deep. The natural pattern of colonisation is by the extension of rhizomes (up to 1.5m in late summer). In older (uncut) stands the remains of older plants accumulate as litter and the level of the marsh surface becomes raised. This can eventually cause the surface to dry out and for a variety of other marshland plants to invade. Scrub (willow and alder carr) eventually develops with an increasing variety of species. The successional sequence help to define the States and values identified within the guide for restoration purposes. The different stages in succession provide suitable habitat for a range of species, especially birds and invertebrates. An indication of the complex interaction between these stages and other, physical attributes, which help to determine the biological diversity on an individual site are depicted below (after Andrews & Ward 1991).

Stages in the succession of reedbed in relation to some of the key species which inhabit them:

Contents 1 INTRODUCTION TO REEDBED 1.1 Origins and definitions 1.2 Traditional management 1.3 Reasons to restore 1.4 States and values 1.5 Guidance (routes to restoration) 1.6 Key Publications 2 Biodiversity importance of reedbeds in the UK 3 Notes 4 Comments 4.1 References and Sources

INTRODUCTION TO REEDBED

Origins and definitions

Reedbeds in the UK and most of Europe are dominated by Phragmites australis. They occur at the margins of tidal land where brackish to freshwater transitions occur, and in freshwater pools. It is a vigorous species which can quickly invade shallow open water and may develop through succession into damp scrub and woodland. The species is essentially a primary coloniser which under natural conditions either invades new areas (on large sites) or reinvades areas where changes in water levels cause degeneration in older stands. Reedbeds can be extensive monocultures in areas flooded year round (reed swamp). Where periodic flooding occurs or where drainage water runs through the site reed fen develops which tends to have a more diverse vegetation.

Traditional management

Because of their natural tendency towards scrub and woodland development, in areas where opportunities for new reedbed are restricted their survival and that of their associated plant and communities is almost entirely defendant on management. In the past cutting reed for thatch would have been a major use and is still practiced at a few sites; the largest probably being the reedbeds of the Tay Estuary, Scotland. Manipulation of water levels and other management activities have become important for nature conservation. The Royal Society for the Protection of Birds has a number of important coastal reserves where intensive management is practiced (see for example, Minsmere).

Reasons to restore

Reedbeds (and the species which rely upon them) are a rare habitat. Drainage (and enclosure of estuarine reedbeds) has reduced their area considerably. No estimates of the losses have been made, but it is considered that the national (UK) resource of reedbeds has declined markedly in extent and quality and with it the rare plants and animals which depend upon it. Whilst colonisation is essential for the development of mature reedbeds, succession to scrub and woodland is often seen as retrogressive.

States and values

The nature of the reedbed and its importance for wildlife depends to a large extent on the stage in succession it has reached. Large areas of reedbed with areas of open water, including ditches (State 2) are most important for nature conservation reasons. Under normal conditions the natural succession is from newly colonising plants (State 1) to the development of scrub and woodland (State 3). Large areas of reed swamp can have an economic value for reed thatch and are increasingly used as a means of treating effluent (see LIFE Reedbed Project).

Guidance (routes to restoration)

Two approaches to reedbed restoration are considered within the Guide (Creation and control):

1. Creation of new reedbeds (e.g. by reprofiling land levels);
2. Control of vegetation (e.g. by reversing succession and manipulation of water levels).

Much of the information on restoration methods is derived from work which aims to secure habitat for the bittern and other rare breeding birds. The RSPB has played a major part in this work and has produced a number of key publications (see below). There are also two LIFE projects concerned with reedbed creation, the first is concerned with reestablishing the bittern in the UK the second provides for the establishment of a series of

Key Publications

• Guides: [RSPB - (RSPB 4, Reserves Management Information sheets); Reedbed management for commercial and wildlife interests (Hawke & José 1996] (Niedowski 2000, a USA saltmarsh Guide, which includes sections on reedbeds)
• Web sites: EUREED a bibliography of Phragmites papers (Denmark); Virginia Institute of Marine Science Centre for Coastal Resources Management (VIMS). The RSPB has valuable information on its web site @ http://www.rspb.org.uk/ follow the links countryside/reserves management/habitats/reedbeds http://www.rspb.org.uk/countryside/reservesmanagement/reedbed.asp?FeatureID=31214&ComponentID=31660&SourcePageID=31215#1

Biodiversity importance of reedbeds in the UK

Reedbeds are a nationally scarce habitat, and dependant wildlife are often scarce. Reed swamps support characteristic communities of uncommon birds and invertebrates (Table 1). Reed fen habitats are more important for their plant and invertebrate interest.

The national resource of reedbeds has declined markedly in extent and quality. Many of the dependant species are now consequently rare or threatened in the UK. Hence, there is a need to increase the extent and quality national resource for biodiversity conservation. Reedbeds are also being created in the treatment of effluents has seen a resurgence in reedbed creation in the last decade and which is helping to offset the historical loss of this habitat.

(Source: Advisory department/Ecology department)

Notes

Important species of reed swamps

• Plants
  • cowbane
  • meadow thistle
  • greater spearwort
  • greater water-parsnip
• Birds
  • bittern
  • marsh harrier
  • bearded tit
  • Savi's warbler
  • Cetti's warbler
• Insects
  • reed leopard moth
  • Fenn's wainscot moth
• Mammals
  • water vole
  • otter

A quick guide to the ecological requirements of the flora and fauna of reedbed

Group/species	General requirements
Breeding birds	Bittern require abundant fish stocks. They hunt along the reed/open water interface in shallow water in reedbeds that are >20 ha, with 20% open water and at least 600 m of reed edge per hectare. These prescriptions will also benefit other reedbed breeding birds. Bearded tit have taken to nesting artificial nest 'boxes' in new reedbeds.
Fish	Reed-fringed shallow water and open water with abundant aquatic plants are important. Connectivity with rivers is often required to ensure recruitment of eels and other species.
Invertebrates	All stages of reedbed succession support important invertebrate communities. Maximum diversity occurs in areas of reedbed with a dry litter layer.
Amphibians and reptiles	Amphibians use well-vegetated water bodies within the reedbed. Grass snakes can be abundant in reedbeds, using piles of cut vegetation to lay their eggs.
Mammals	Reedbeds can host high densities of harvest mouse, which feeds on invertebrates in the summer and seed during the winter, and water vole. Other mammal species present are largely linked with aquatic habitats, eg otters which require abundant fish and amphibian stocks.
Aquatic flora	Ditch and water body profiles should create abundant shallow water for submerged macrophytes and emergent vegetation. Most aquatic plant species prefer mesotrophic-eutrophic conditions with a neutral to slightly acidic pH.

Comments

These notes are aimed at someone studying for A Level geography, more specifically, AQA synoptic paper on coastal management.

The notes were originally submitted by geojane in this post on TSR Forums.

References and Sources

Niedowski, N.L. 2000. New York State Salt Marsh Restoration and Monitoring Guidelines. New York State, Division of Coastal Resources & Division of Fish, Wildlife and Marine Resources.

RSPB 4 Establishing and Managing Reedbeds. Reserve Management Information sheets Royal Society for the Protection of Birds.

Hawke, C.J. & José, P.V. 1996. Reedbed Management for Commercial and Wildlife Interests. RSPB, Sandy