Fen Management Handbook - Scottish Natural Heritage

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8.2.2 Livestock management Phosphorus is a major component in poultry, pig and milking cattle feed, but is frequently above livestock’s requirement. When excreted and eventually spread onto fields, there is a risk of excessive phosphorus enrichment. N and P excretion from pig units can be reduced significantly by changes in feedstuffs, which can also prove cost effective for farmers. A synthetic form of P (phytase) can be added to the diet of poultry and pigs, which decreases the P in manure. Provision of cattle bridges and fencing to reduce poaching can also be significant in reducing nutrient enrichment (see 6.2.9). 8.2.3 Other land management A range of other techniques can be used to reduce the release of nutrients and other pollutants within the catchment, for example: – Installing phosphate-stripping plants on sewage treatment works that discharge into a river that forms part of a fen’s water supply. – Installing or repairing systems which separate clean (mainly rainfall) and dirty water in farm-yards. Replacement of septic tanks with mains sewerage treatment See Defra, UK - Environmental Protection - Water - Diffuse pollution of water Further specialist advice is recommended to assess appropriateness of these options to specific locations and design detail, particularly for options likely to incur high capital costs (see Appendix V for further advice). 8.3 Managing nutrient pathways 8.3.1 Reedbed filtration Passing the water which feeds a fen through a reedbed can help trap the majority of the suspended solids and some of the dissolved nutrients before it enters the fen. The reedbed might be a separate area to the fen, specially constructed, or a part of the fen set aside for this purpose. The size of the treatment reedbed needs to be matched to the nutrient loading (i.e. concentration of nutrients multiplied by estimated flow) of the incoming water. Not surprisingly, larger wetlands are required for heavier loadings, but small in-line wetlands can be effective where a fen is fed by seepage, small ditches or streams. The principles of constructed reedbed treatment systems are well known: water draining vertically down through the rhizomes is used initially to convert any ammonium present to nitrate. Another design, in which water passes laterally through the rhizomes, denitrifies the nitrate to gaseous forms of nitrogen. There will be some uptake of N by the reed, but this is eventually recycled through decomposition of the leaf litter. A high rate of P removal can be achieved by using a highly alkaline or calcareous substrate, such as limestone or crushed brick rubble, so that the phosphate is adsorbed/precipitated to calcium carbonate and other calcareous minerals such as apatite. Constraints on the design of any constructed reedbed may arise from available space, topography and variability in the flows of water in the inflow stream. <strong>Natural</strong> reedbeds are used for water treatment under certain circumstances, though there may be negative impacts on their conservation value. Hawke and José (1996) and the Constructed Wetlands Association can provide further details. Drains at the edge of a fen can be used to help intercept nutrients – particularly if vegetated with species which are responsive to nutrients. In addition routing drains into constructed wetlands will improve the effectiveness of nutrient removal. 176
Marginal interceptor ditch at Cors Erddreiniog (P.Jones). 8.3.2 Buffer zones Buffer zones are areas established immediately around a fen, or along streams, drains and ditches that bring water to a fen, to intercept nutrients which might otherwise enter the fen as a result of adjacent land management activities. Buffer zones work by increasing the residence time of water in the soil before the water enters the fen, allowing enhanced removal of soluble nutrients by plant and microbial uptake (bacterial denitrification being a key process) and removing sediments by physically trapping the particles. Oligotrophic Anglesey fen bordered by improved grassland within a dairy farm. The marshy grassland at the edge of this fen acts to some extent as a nutrient buffer, but better site protection would require definition of a formal buffer zone within the field (P. Jones). 177
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The Fen Management Handbook Edited
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Acknowledgements Production of the
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1. Introduction and Basic Principle
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Estimates of the original coverage
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Guiding principles for fen manageme
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Section 12: Fens from an Economic P
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2.1 Diversity and conservation sign
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Part of Cropple How Mire in Cumbria
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The moss flora of base-rich springs
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Bog bean growing in a transitional
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Mesotrophic openwater transition fe
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Water shrews (Neomys fodiens), also
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2.4.1 Vegetated margins of open wat
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2.4.3 Grazed or cut fen in floodpla
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2.6 Amphibians Amphibians are depen
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The mud snail Omphiscola glabra (12
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Old trees and dead wood Continuous
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Vascular plants Flat-sedge Blysmus
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3. Understanding Fen Hydrology Quan
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Groundwater discharge to fens is us
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Water Table 3.4.1.4 Spring fed fen
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3.5 Factors determining fen type 3.
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- Flooding - frequency and magnitud
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3.7 Further information and advice
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Groundwater inflow. Groundwater lev
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It is likely that groundwater disch
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Case Study 3.3 Hydro(geo)logical im
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4. Understanding Fen Nutrients Nutr
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nutrients. For example, at high con
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4.2.1 Groundwater and surface water
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4.2.3 Point and diffuse sources of
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Area of acute nutrient enrichment o
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4.4 Classifying water chemistry usi
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4.6 Identifying nutrient enrichment
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Negative indicator species for diff
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Many of the floristic changes which
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Case Study 4.1 Understanding Fen Nu
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5.1 Why do fens need management? In
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5.2 Checklist of key stages in deci
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5.3.3 Scale Although fens are linke
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5.4 Site survey to establish what i
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variability and how these relate to
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- The fauna which inhabit the fen c
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- Prioritise objectives to achieve
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inundation are less likely to be sp
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5.13 References Barsoum, N., Anders
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Case Study 5.2 Fen Management and R
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- 14km of livestock fencing install
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Case Study 5.3 Fen Management and R
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6. Fen Management and Restoration -
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Both the benefits and potentially l
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Cattle forced by flooding to the ed
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At low/medium stocking density, cat
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Goats have narrow muzzles and a fle
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Fens usually feature a range of dif
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Excessive poaching where cattle hav
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extensive areas of wetlands which w
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‘Soft track’ machines, such as
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The design of the pipeline allows f
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Protocol for burning standing reedb
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Long rotation scrub clearance may b
Page 123 and 124: ‘Bird-eye’ and incineration A t
Page 125 and 126: 6.7 Restoring fen meadow Many forme
Page 127 and 128: Current Management The current mana
Page 129 and 130: Case Study 6.2 Fen Vegetation Manag
Page 131 and 132: species diversity of wetland passer
Page 133 and 134: The temptation to burn large areas
Page 135 and 136: Outcomes In the eight years that th
Page 137 and 138: Anglesey sites is now underway supp
Page 139 and 140: Close grazed short sward of sedges
Page 141 and 142: Turf cutting Turf cutting has been
Page 143 and 144: 7.1 A framework to assist decision
Page 145 and 146: Surface water level change e.g. - a
Page 147 and 148: and the surface to acidify, resulti
Page 149 and 150: Smaller excavations are preferable
Page 151 and 152: Morton Lochs, which extend to appro
Page 153 and 154: Although shallow excavations are pr
Page 155 and 156: At Leighton Moss in Lancashire, are
Page 157 and 158: Excavating spoil within the area to
Page 159 and 160: uilt dams can only be formed in dit
Page 161 and 162: Case Study 7.1 Fen Water Management
Page 169 and 170: 8. Managing Fen Nutrient Enrichment
Page 171 and 172: Summary table of key techniques for
Page 173: 8.2 Managing the source of nutrient
Page 177 and 178: 8.3.4 Bund creation In some cases i
Page 179 and 180: emoval or soil stripping, both of w
Page 181 and 182: 8.5 Monitoring nutrient reduction D
Page 183 and 184: Recent photo of stripped surface sh
Page 185 and 186: 9.1 Scope for fen creation The Grea
Page 187 and 188: 9.3 What type of fen? New fens can
Page 189 and 190: 9.5 Restraints on fen creation Plan
Page 191 and 192: 9.6 Check list of issues to conside
Page 193 and 194: 9.7 Site assessment Planning and de
Page 195 and 196: LIDAR maps can provide a general un
Page 197 and 198: generally more acidic than silts an
Page 199 and 200: Site visits and careful assessment
Page 201 and 202: 9.8.4 Plastic membranes On sites wi
Page 203 and 204: Use of seed bombs ‘Seed bombs’
Page 205 and 206: Experience has shown that the most
Page 207 and 208: 9.10.2 Creation of niches for plant
Page 209 and 210: Meade, R. & Wheeler, B.D. 2007. Rai
Page 211 and 212: - On-going measurement of the effec
Page 213 and 214: with appropriate training. Providin
Page 215 and 216: 10.3 Biological monitoring techniqu
Page 217 and 218: Undesirable species for key NVC com
Page 219 and 220: 10.3.3 Vegetation Mapping An initia
Page 221 and 222: It is good practise to record with
Page 223 and 224: 10.4 Biological monitoring techniqu
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for Ornithology, the Bat Conservati
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Box 2: Construction, installation a
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10.8 Monitoring surface water flows
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- Phytometric tests measure how wel
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Storage of data and information on
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period, simply because it is design
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Another consideration is the likely
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11.1 An historical perspective Poll
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Inviting volunteer involvement in f
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11.3.3 Stakeholders ‘Stakeholders
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have been designated under access a
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11.6.4 Boardwalks Boardwalks are no
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11.6.5 Water borne access Waterways
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- Explore opportunities to stimulat
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Case Study 11.1 Fens and people - S
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Case Study 11.2 Fens and People - H
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12. Fens from an Economic Perspecti
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12.1.3 Biomass energy and Biofuels
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12.2 Environmental regulation 12.2.
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the peat carbon store is depleted t
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Another mechanism for funding wetla
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Whitlaw Mosses in Scotland (see det
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12.8 References Dickie, I., Hughes,
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Nitrogen fixation conversion of gas
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Appendix III - List of species refe
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Table 1 - Mammal species associated
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280 Bittern Botaurus stellaris All
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Grasshopper Warbler 282 Locustella
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Table 4 - Fish species associated w
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Table 5 - Legally protected inverte
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288 Community Topogenous fens S24 P
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290 Community S8 Scirpus lacustris
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292 Community M11 Carex demissa - S
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294 Community M23 Juncus effusus /
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Appendix V - Legal and regulatory c
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298 Type of Works Guidance for UK C
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Appendix VI - Fen management for br
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However, three of the four species
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Sensitive periods Harvest mice bree
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species like bittern, and then drop
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Sensitive periods Species breed wit
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Great Crested Newt Great crested ne
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Appendix VIII - Fen management for
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Mollusca (snails, slugs and mussels
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Other than for rare or exceptional
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There is usually some degree of sub
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Management requirements for protect
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Appendix IX - Further reading Secti
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Koerselman, W., Bakker, S.A. & Blom
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Section 5: Fen Management and Resto
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Patzelt, A, Wild, U. and Jörg Pfad
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Index A access 103, 110, 190, 226,
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cutting 114 disposal 117 management
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Fen Management Handbook - Scottish Natural Heritage

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