Section heading Bringing Reedbeds to Life: creating and managing reedbeds for wildlife Graham White, Matt Self and Sarah Blyth Bringing Reedbeds to Life: creating and managing reedbeds for wildlife 3 Andy Hay (rspb-images.com) 2 Bringing Reedbeds to Life: creating and managing reedbeds for wildlife The creation of new reedbeds and the re-invigorated management of existing sites has been a real conservation success in recent years. Significant progress has been made towards meeting nature conservation targets. Much of the work has focused on providing suitable habitat for one of the key associated species, the bittern, which had declined to just 11 booming males by 1997. By 2013 at least 1,500 ha of new reedbed had been created, or was in the process of creation, and restoration work had been undertaken on many of our existing reedbeds. Bitterns increased to 120 boomers, a remarkable response to the work undertaken. During this period, much information has been generated on reedbed design, establishment and management, and work on the ground, combined with continuing research into particular aspects of reedbed or species ecology, has continued to add to our knowledge and experience. This booklet aims to present an up-to-date summary of the techniques involved in creating and establishing reedbeds that maximise their value for wildlife. It is a result of discussion amongst RSPB staff involved in reedbed creation and management, as well as the experience of partner organisations and individuals. Bringing Reedbeds to Life: creating and managing reedbeds for wildlife 3 Steve Knell (rspb-images.com) 4 Contents Chapter one: reedbed wildlife – what does it need? 07 Introduction 07 Invertebrates 08 Fish 09 Amphibians and reptiles 09 Mammals 10 Aquatic flora 10 Birds 10 Chapter two: reedbed creation 15 Key parameters for reedbed design 15 Reedbed establishment 19 Enhancing reedbeds for visitors 24 Chapter three: reedbed management 27 Introduction-why manage reedbeds? 27 Water regime 27 Management by cutting 29 Larger scale management by machines 31 What do we do with the reed cuttings? 36 Management by burning 40 Management by grazing 41 Chapter four: reedbed restoration 43 Bed lowering 43 Reedbed rejuvenation 44 Conclusions 46 Chapter five: case studies 49 Ouse Fen 49 Ham Wall 52 Hickling Broad 54 Minsmere 56 References and further reading 60 This book does not constitute legal or regulatory advice, and you should obtain specific information and advice, and procure all necessary licences and consents, from appropriate public and statutory bodies in connection with any planned works. The RSPB is not liable for any loss howsoever arising from reliance upon or use of this book. No responsibility can be accepted for any loss, damage or unsatisfactory results arising from the implementation of any recommendations made within this book. Authors: Graham White, Matt Self and Sarah Blyth Bringing Reedbeds to Life: creating and managing reedbeds for wildlife 5 Mark Sisson (rspb-images.com) 6 Chapter one: reedbed wildlife – what does it need? c Introduction c Birds c Fish c Mammals c Reptiles and amphibians c Invertebrates Introduction The increased effort to create and this in mind, the “Bringing Reedbeds manage reedbeds in recent years has to Life” (BR2L) project during 2010-11 mainly been directed towards the undertook research to establish a better conservation of the bittern, a bird of understanding of the requirements of the wetter, early successional stages a range of reedbed wildlife, particularly of the habitat. However, although invertebrates. Some of the headline natural succession and associated findings were as follows: drying has been established as a key issue within UK reedbeds, it is clearly • The older, drier parts of the reedbed important to understand and provide support the highest overall invertebrate for the requirements of species across diversity and many invertebrates of the range of reedbed conditions. With conservation importance. Diagram 1. Fish habitat requirements Bringing Reedbeds to Life: creating and managing reedbeds for wildlife 7 • Early successional reedbeds are Invertebrates important for reedbed and wetland specialist invertebrates. Ditches and All stages of the reedbed succession pools add structural diversity and are support important invertebrate important for aquatic invertebrates communities (Kirby 2001). Maximum and plants. diversity is supported by reedbeds with damp, but not flooded, litter layer and an • Reedbeds are dynamic ecosystems; abundance of other reedbed herb species. temporal and spatial variation in Sparse reed with other emergent plants the habitat is key to maintaining a in shallow water is also good. Research in high diversity of flora and fauna. France has suggested that the maximum Management that maintains a range of biomass of invertebrates, rather than successional stages will maximise their diversity, was present in wetter areas conservation value and biodiversity. (Poulin et al 2002). Our knowledge of the requirements of Some invertebrates associated with some of the main reedbed associates, reedbeds feed on the reed itself; others from the BR2L project (Hardman et are predators or parasites of these species. al 2012, Sears et al 2013) and other A further group live within reed stems studies, are summarised in the following but don’t feed on the plant. Many live sections. within the leaf litter, or are aquatic species living amongst the emergent stems. The reedbed structure is important for many of these species (Kirby 2001). Reedbeds are particularly noted for a number of scarce moths. Wet reedbeds are favoured by those species whose larvae feed and pupate within the foodplant. Characteristic species include the brown-veined wainscot. The larvae of the micromoth Schoenobius gigantella find fresh food by floating from stem to stem on a raft of reed stem. Drier reedbeds favour those species that pupate in reed litter or underground; these include fen wainscot, silky wainscot, reed dagger, Fenn’s wainscot, white-mantled wainscot and reed leopard. The early successional phases of reedbeds can be important for a range of scarce diptera. Overall, invertebrate interests are best served if all stages of reedbed succession, from young reed in open water to old reed with scrub invasion on almost dry Graham White RSPB ground over dense litter, are provided. The juxtaposition of the stages can be important as many invertebrates have different requirements at various times in their life cycle. Small scale variation within a broader mosaic is likely to be desirable. Variation in associated habitats is also important: bare marginal substrates can be very important and shallow pools/ ditches with abundant emergent and submerged aquatic vegetation generally support a diverse invertebrate fauna. Small scale management and restoration may Species such as the twin-spotted wainscot may be cyclically be important for maintaining a range of abundant within reedbeds, causing typical signs on reed stems successional phases within the reedbed. of exit holes below the dying tip of the stem. 8 Bringing Reedbeds to Life: creating and managing reedbeds for wildlife Chapter one: reedbed wildlife – what does it need? Fish colonisation. Stocking is not a sustainable solution, but where the wetland design Fish biomass and abundance is generally has provided all the habitat types greater in shallow (about 1 m depth) required for the life cycle, the seeding of open waters and lakes than in reedbed/ locally appropriate species to establish a ditch systems. Therefore, reedbeds breeding population could be considered. will ideally contain, or be connected to, The fish community of a new wetland plenty of open water of at least that will often follow a successional pattern, depth, and preferably of varied depth, with the early stages dominated by with abundant aquatic plants. Pools piscivorous species, such as perch within reedbeds are preferred to ditches, and pike, followed by an increasing although connected deep ditches may dominance by cyprinids such as roach be useful winter habitat. Cyprinid fish and rudd. However, this will depend on typically exhibit seasonal variations in the fish present at the outset and any both distribution and habitat use. Adult introductions. fish generally gather in deeper, more sheltered waters during the winter months. In the spring, more open, Amphibians and reptiles warm, vegetated shallows less than 1.5 m deep are important for spawning Amphibians require well-vegetated and sheltering fry. Fish may also exhibit water-bodies within the reedbed, diurnal variations in distribution, using preferring gentle bank gradients, the littoral zone more by day and open shallower depths and in general, an water more by night. Connectivity within absence of fish. Common frogs prefer the reedbed system is vital to allow unshaded, seasonally flooded areas. movement between seasonal habitat Marsh frogs are more associated with preferences. Connectivity to rivers is also reedbed water-bodies and seem to be important (if the water quality is suitable) more tolerant of fish. Grass snakes can particularly to ensure the recruitment of be abundant in reedbeds, using piles of eels and their subsequent return to the cut reed vegetation in which to lay their sea. Eel passes should be used where eggs. Surrounding rough grassland/scrub appropriate. habitats are important. Creating isolated and seasonally drying pools around Overall, diversity in underwater structure, the margins of the reedbed should be with variations in bed depth and deeper considered for amphibians. Areas of refuge areas, is important to ensure that winter flooded land around the margins the seasonal microhabitat preferences of reedbeds (“blue-zone” areas – see of a range of fish species are met. Small page 16) may also be important. scale features such as flooded deer tracks on the edge of ditches can add structural variation and be valuable for (RSPB) Self Matt small fish. Similar features can easily be created along ditches with an excavator. Artificial underwater habitat in the form of rock piles, reefs or brash-bundles may also be created in the open water.