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Working Wetlands HLS Special Project
Dunsdon Farm
Re-Creation of Species-rich, Semi-natural Grassland
Management Plan
2008-2013
Prepared by:Becky Aston
Advisory Officer Working Wetlands
Devon Wildlife Trust, Working Wetlands Project, Cookworthy Forest Centre,
Beaworthy, Devon. EX21 5UX
Tel: (01409) 221823 Fax: (01392) 433221
E-mail:
Web site: charity, no 213224
Devon
Dunsdon Farm
Management Plan: Restoration of Culm Grassland
2008 - 2013
Devon
I%se1. Site Information / 2
2. Introduction / 3
3. Habitat Description / 3
4. Project Rationale / 4
5. Project Description / 4
5.1 Phase 1 - Soil Stripping Operations / 4
5.2 Phase 2 - Restoration / 6
5.3 Phase 3 - Sward Establishment / 7
5.4 Operation Guidelines / 9
5.5 Access / 10
5.6 Historic Environment / 10
5.7 Health and Safety / 11
5.8 Future Management / 11
5.9 Monitoring / 13
6. Management Prescriptions / 15
Appendix 1 - Maps / 18
Appendix 2 - Capital Works Schedule / 20
Appendix 3 - Restoration Plots Seed Mix / 21
Working Wetlands/Aston/01 /12/2009
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1
Dunsdon Farm
Management Plan: Restoration of Culm Grassland
2008-2013
Devon
1.Site Information
Owner: Mr Paul Stenning
Farm Address:
Dunsdon Farm
Pancras Week
Holsworthy
Devon
EX22 7JW
Working Wetlands Advisor: Becky Aston
Working Wetlands Project Officer
Cookworthy Forest Centre
Beaworthy
Devon
EX21 5UX
01409 221823
Natural England Advisor: Justin Gillett
Natural England
Level 8 - Renslade House
Bonhay Road
Exeter
Devon
EX4 3AW
0300 0600441
WWID:
Site Location:
Dunsdon Farm, Stenning, 925
Grid ref: SS301084 (centroid)
Special Project Field Numbers:
SS30082518
SS30088430
SS30080323
SS30089322
Stewardship Agreement Ref:AG00260445
Working Wetlands/Aston/01/12/2009
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Dunsdon Farm
Management Plan: Restoration of Culm Grassland
2008-2013
wildlife
TRUSTS
Devon
2. Introduction
Dunsdon Farm is located in the Torridge and Tamar Working Wetlands priority area. This has been identified due to the quantity and quality of wildlife-rich habitats present. The Working Wetlands project aims to restore these important sites into good environmental condition and strategically reconnect habitats so that they can support rare and threatened wildlife into the future. Management of these habitats will also have a positive impact on water quality and also reduce flood risk downstream.
The management plan focuses on the delivery of a Natural England special project involving an area of semi-improved rush pasture at Dunsdon Farm. The management plan applies to the soil stripping, shallow ploughing and sowing with a wildflower rich seed mix at Dunsdon Farm, and subsequent site works to enable restoration to species-rich grassland. This project aims to restore the semi-improved grassland to species-rich grassland and restore the network of small fields through hedgebank creation and hedge planting.
The special project also aims to create a demonstration farm showing the re-creation of unique Culm and wet grassland. The re-creation of Culm Grassland at this farm fits in with other Culm Grassland projects in the direct locality such as re-creation from conifer plantation. The site will be utilised to promote best practice to landowners and conservation sector employees.
The Site Management Plan can be reviewed at any time by Natural England or Devon Wildlife Trust should monitoring show it to be necessary, in discussion and agreement with the landowner. If circumstances change substantially a review may also be called for at 3 months notice from either party to the HLS Agreement. The management plan should be viewed and agreed by all stakeholders.
3. Habitat Description
The compartments at Dunsdon Farm subject to the grassland restoration process occupy ground to the north of Dunsdon SSSI, with the compartments having a gentle northerly aspect, towards a minor road to the south. Site access is via this road. There is a rich hedgerow resource found at Dunsdon Farm including species rich hedgerows and under storey flora. Traditional Devon hedgebanks are present on all boundaries. Historically the field boundaries present at the farm created a series of small fields. Some broadleaf trees are present on the hedge-banks and a small compartment (0.6 ha) of mixed broadleaf woodland at the northern end of the Culm Grassland CWS will be retained.
The current vegetation community has been empirically assessed and matches well to a MG10 (Holcuslanatus - Juncuseffusus rush-pasture) community in transition to M23/MG6 (Juncuseffusus/acutiflorus-Galiumpalustre rush-pasture/ Loliumperenne - Cynosuruscristatus grassland). The grassland is dominated by perennial rye-grass, Yorkshire fog and crested dog’s-tail. Soft rush dominates in areas where drainage is impeded. The herb flora is dominated by creeping buttercup and common birds foot trefoil with occasional meadow
Working Wetlands/Aston/01 /12/2009
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Dunsdon Farm
Management Plan: Restoration of Culm Grassland
2008 - 2013
wildlife
TRUSTS
Devon
buttercup, ragged robin, selfheal and common mouse-ear. Other herb species present include ribwort plantain, black knapweed, sneezewort, common sedge, oval sedge and white and red clovers.
4. Project Rationale
A number of published scientific papers have described Rhos and neutral grassland restoration and sward enhancement trials e.g. 2007 Mortimer S R, et al.; 2003 Adams WA, Young RJ; 2001 Walker KJ, et el. In the Culm Natural Area to date, this work has not left the scientific establishment and been employed to restore grasslands in the wider countryside. This has been due in part to scarcity of funds and also lack of land strategically located, of the correct soil type and nutrient status. The key factor however is that the landowners at Dunsdon Farm actively support restrictive operations within the farm. The conclusions of the published papers have been employed where practical in this management plan.
The land affected by the trails has been identified under the Culm Grassland Restoration Suitability Map as Level 4 (levels 1-5, 5 most suitable). This map identifies the inherent restoration characteristics of Culm (mire) habitat by assessing factors such as slope, catchment, soils and hydrology. This research was funded by Natural England; the next phase of this project is to trial different restoration techniques at field scale within core strategic areas in order to better understand the mechanics of mire habitat restoration and to ultimately re-connect fragmented habitats so that they may function in a more naturalistic and resilient manner.
The area of semi-improved grassland within Dunsdon Farm lies in a very strategic location adjacent to several areas of Culm Grassland habitat. The proposed project will create a larger, well connected, more ecologically resilient landscape; this will have a significant positive impact on the viability of the Marsh Fritillary meta-population and other wildlife sustained in this area. Map 1 illustrates the vital link in the ecological system that the proposed works will forge.
5. Project Description
The landowner, with the support of Devon Wildlife Trust’s ‘Working Wetlands’ project, is proposing to re-create semi-natural Culm Grassland habitats on land that is currently semi-improved grassland. The project is proposed to occur over a month period enabling soil stripping operations, harrowing and re-seeding to occur simultaneously in the minimum time necessary with the aim of reducing run-off and soil erosion.
The overall project is a phased programme of works supported by Natural England. Briefly these can be summarised as follows:
Working Wetlands/Aston/01 /12/2009
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Dunsdon Farm
Management Plan: Restoration of Culm Grassland
2008 - 2013
wildlife
TRUSTS
Devon
5.1Phase 1 - Soil Stripping Operation
In field 2518 each relevant compartment (see below and Figure 1) must be soil stripped in full in the period between May to June. All risings from each compartment must be used to restore the historic hedge-banks or spread over the adjacent fields as per Figure 2. Estimated amounts of soil risings are as follows (refer to Figure 2):
See Map 2 - Appendix 1 for compartment locations.
Compartment 1
Turf strip 15cm retaining approximately 10-15cm of top-soil.
Estimated amount of soil risings:
10150m2 at 0.15cm depth = 1523m3
Compartment 2
Receptor for soil risings.
Compartment 3
a. Turf strip 15cm retaining approximately 10-15cm of top-soil.
Estimated amount of soil risings:
4399m2 at 15cm depth = 660m
b. Strip top soils to a maximum of 30cm retaining <5cm of topsoil above clay horizon.
Estimated amount of soil risings:
6423m2 at 30cm depth = 1927m3
The more intensive treatment has been selected for this compartment due to the higher phosphate level result from soil sampling.
Compartment 4
Only a third of this field parcel is to receive treatment due to the volumes of soil risings created overall.
a. Turf strip 15cm retaining approximately 10-15cm of top-soil.
Estimated amount of soil risings:
2747m2 at 15cm depth = 412m
b. Receptor for soil risings.
Compartment 5
Shallow plough 9137m2 to a depth of 10cm.
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Dunsdon Farm
Management Plan: Restoration of Culm Grassland
2008 - 2013
wildlife
TRUSTS
Devon
This less intensive treatment has been selected for this compartment due to the transitional nature of the entire field.
Compartment 6
Receptor for soil arisings.
Total soil risings created = 4522m3
5.2Phase 2 - Restoration
The hedgebanks will be restored utilising the turf created from the first stages of soil stripping. Turfs should be stripped to a depth of approximately 10cm (or depth of root mat) for the construction of the hedge bank. The banks should be constructed by layering turfs and forming a smooth exterior with further turf strips. This will give greater stability during bank construction, enabling a steeper batter, leading to less slumping and run-off. The bank should be constructed to the following dimensions (refer to Figure 2 for boundary locations):
Boundary 1 (HLS Boundary Ref: 39)
2.5m wide at the base with an incline that will reduce the top to 1.5m and a height of 1.5m and a length of 238m.
Soil risings used = 714m3
Boundary 2 (HLS Boundary Ref: 40)
2.5m wide at the base with an incline that will reduce the top to 1.5m and a height of 1.5m and a length of 58m.
Soil arisings used = 174m3
Boundary 3 (HLS Boundary Ref: 41)
2.5m wide at the base with an incline that will reduce the top to 1.5m and a height of 1.5m and a length of 104m.
Soil risings used = 312m3
Boundary 4 (HLS Boundary Ref: 42)
2.5m wide at the base with an incline that will reduce the top to 1.5m and a height of 1.5m and a length of 111m.
Soil risings used = 333m3
Assuming the banks are well compacted and constructed to dimensions of 2.5m wide and 1.5m high approximately a total 1533m3 of soil arisings will be required.
Working Wetlands/Aston/01/12/2009
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Dunsdon Farm
Management Plan: Restoration of Culm Grassland
2008-2013
wildlife
TRUSTS
Devon
The remaining 2989m3 of soil risings will have to be moved to compartments 2,4b and 6 as per Figure 1. These compartments currently support species-poor rye grass/Yorkshire fog dominated communities.
Compartment 2
Evenly spread top soils to a depth of 10cm and harrow.
Estimated amount of soil risings to be dispersed:
9312m2 at 10cm depth = 931m3
Compartment 4b
Evenly spread top soils to a depth of 10cm and harrow.
Estimated amount of soil risings to be dispersed:
5494m2 at 10cm depth = 549m
Compartment 6
Evenly spread top soils to a depth of 20cm - 30cm profiling with the slope of land and harrow.
Estimated amount of soil risings to be dispersed:
Minimum = 7391m2 at 20cm depth = 1478m3 Maximum = 7391m2 at 30cm depth = 2217m3
In all compartments the soil will be evenly spread then harrowed and sown with a wildflower rich grass mixture.
5.3Phase 3 - Sward Establishment
Seed Mix
All compartments will be treated equally for the purposes of sward establishment. A bespoke seed mix supplied by Emorsgate seeds will be used and a full species list and is shown in Appendix 3 - Emorsgate will create a mixture by relative proportions that will enable the sward to be created and the structure to be correct to encourage seedling germination; for example a high proportion of crested dogs tail is used as this species fluctuates in abundance creating structure in the sward.
This will ensure a sward is established in a short time frame reducing potential soil run-off and the growth of invasive and ruderal weeds. It also enables a vegetation community to be selected which suits the conditions rather than a green hay mixture being used because of availability rather than ecological ‘fit’.
Sowing the seed mixture evenly onto prepared soil is the most successful method for establishing a mixture. Most wild species will do better on the thinner soils and poorer soils will produce more varied and more attractive vegetation, and will be easier to manage.
Working Wetlands/Aston/01/12/2009
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Dunsdon Farm
Management Plan: Restoration of Culm Grassland
2008-2013
Devon
Operations
For Soil Stripped Areas:
To create a suitable seed bed the soil should be cultivated to sufficient depth to bury remaining trash and to alleviate compaction, then harrow and roll to produce a fairly fine, firm surface. The finished seedbed should be firm enough to walk on without leaving impressions. The finished surface should be free of obstructions, such as large stones or bricks, and free of deep ruts or ridges so as to enable normal agricultural operations to take place.
For Shallow Ploughed Areas:
Before works begin the sward should be cut or grazed hard in the autumn, aiming to keep the grass short (30-50mm). The compartment should be grazed both before and after seeding as needed. To create gaps across the site with exposed soil for seed to germinate in the compartment needs to be shallow ploughed with a 40-50% destruction of the turf layer.
All Operations (Soil stripped, shallow ploughed and arising areas):
Ideally the seed should be broadcast on to the prepared seed bed using a single disk fertiliser spinner or similar. To achieve an even sowing, bulk with an inert carrier such as dry sand (sawdust or cornmeal is better for mechanical distributors where sand can cause damage to mechanisms). To get even distribution, and also avoid running out of seed part way through a job, the quantity to be sown should be split in half, with the entire area sown twice at half the rate. The first half should be sown in one direction, with the remaining seed over-sown in another direction. Seed should be spread in still conditions to avoid seed drift.
Do not harrow the seed in as most wild seeds are very fine and cannot germinate if buried. To germinate seed will need to connect with moisture in the soil. In drier conditions this can be achieved by rolling. Rolling before and after seeding presses seed into contact with the soil and brings moisture to the surface by capillary action in the firmed soil. One or two passes with a roll after sowing with will firm and level the surface and create good seed/soil contact. In wet weather a good rain after sowing will wash the seed in and settle the soil surface without needing to roll. The seed bed should not be rolled when the soil is very wet as this may compact and damage the soil surface.
Ideally, a Cambridge (ribbed) roll should be utilised as it leaves a textured surface of small ridges and furrows which is better for soil stability and gives some wind protection to emerging seedlings. However, flat rolls will do an adequate job.
The ideal vegetation community to establish in the early years after sowing would be a moderately species rich grassland characteristic of a transitional habitat to a mire from a more base rich grassland (MG5-M24 transition).
Natural England will fund the site preparatory works (soil stripping, redistribution of soil arisings and seed sowing) through Special Project funding at 100%. Further capital works
Working Wetlands/Aston/01 /12/2009
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Dunsdon Farm
Management Plan: Restoration of Culm Grassland
2008 -2013
wildlife
TRUSTS
Devon
required to restore site management will be the responsibility of landowner, but will receive funded support through HLS capital works grants (please refer to schedules in Appendix 2 for quantities and values).
5.4 Operation Gudelines
Good Practice
Each compartment must be left in a condition after soil stripping and special project operations that:
• Exemplifies good practice for handling soils. The site must be left clean of all arisings (Internet address:
• Creates ground conditions that facilitate management with machinery found in normal agricultural situations (i.e., small tractor and topper);
• Produce minimal nutrient release that could inhibit a desirable community from regenerating. Unnecessary ground disturbance should be avoided throughout the restoration period.
• Access points through boundary features need to be agreed by Natural England prior to works commencing. No new access points will be created without prior agreement with Natural England.
Buffer-zones
2 m buffer-zones (i.e. no heavy-plant fuelling or machinery maintenance within these zones) are located alongside the field boundaries.
Tracked or wheeled machinery can enter these zones but soils cannot not be removed.
No chemical storage can occur within the buffer-zones, and ideally not within the project sites at all. Codes of good practice should be adhered to.
Within the buffer-zones (identified during site visits prior to operations), refuelling must not take place. If other maintenance is required which may result in the spilling of fluids or lubricants, this must take place outside of restoration compartments.
Wildlife
Thorough checks must be made within the compartments for ground nesting birds throughout the operations period. If nesting is confirmed or suspected, works must cease until the end of the nesting period and fledging of the young to avoid disturbance. Checks by the agent will be made for scheduled nesting bird species prior to works commencing. It is the responsibility of those working on site to ensure regular checks are made throughout the works period.