Bumpers Lane Management Plan

FIELDWORK Ecological Services

(Kevin Cook B.Sc. and Associates)

Management Plan for part of Silklake SNCI, the northern meadow and Attenuation Pond at Bumpers Lane Depot, Easton, Portland, Dorset

Linked to planning applications: WP/17/00017/RES, WP/14/00330/FUL and WP/17/00372/FUL

Kevin Cook 13th February 2019, Updates 14th March 2019, 7th August 2019, 23rd October 2019

EDITED FOR THE PURPOSE OF THE WEBSITE 2024

70 Back Lane, Okeford Fitzpaine, Dorset. DT11 0RD

Phone 01258 861557 Mobile: 07809017874

E-mail: kevincookecology@gmail.com

Management Plan for part of Silklake SNCI, the northern meadow and Attenuation Pond at Bumpers Lane Depot, Easton, Portland, Dorset

Grid Ref. SY 697715

1. Background

This Plan fulfils the requirement of the Section 106 Agreement signed on the 24th June 2015 and planning documents WP/17/00017/RES, WP/14/00330/FUL and WP/17/00372/FUL that require a Wildlife Management Plan (WMP) for three discrete areas as shown in the Plan 1 below. These are:

Area A. The Wildlife Management Area (WMA) within blue boundary shown on the incorporated plan. This area largely includes land within the boundary of the Silklake Site of Nature Conservation Interest (SNCI), designated because of its importance for unimproved calcareous grassland.

Area B. A grazed pasture of semi-improved grassland.

Area C. The attenuation pond and surroundings.

NOTE: there is no management proposed within this plan for land south of the haul road.

2. The Management Plan Aims

2.1 Desired State

The natural character of the larger area of the Isle of Portland is of a varied topography and habitat with rabbit grazed short turf species-rich grassland and associated bare ground habitats, areas of tall sward grassland, and patches of thorn and other scrub. This is the ‘desired state’ of the Management Plan. The character of the locality has been recognised with two forms of designation:

Immediately east of the development site is an area that includes unimproved calcareous grassland, a Biodiversity Action Plan habitat, scattered around the former Chalklands Quarry. This forms part of the larger Silklake SNCI – some of the boundary of the SNCI does extend into the proposal area but not the BAP habitats that the SNCI was designated for.

South-east of the study area, less than 200 metres away is part of the Portland SSSI that is also the Isle of Portland to Studland Cliffs Special Area for Conservation (SAC), an internationally protected site.

Thus, it is important that the proposed development does not cause negative impacts upon these designated sites and positively contributes to their landscape and ecological values. Thus, the ecological justification for retaining and seeking the desired state discussed above is as follows:

Short turf grassland and bare habitats are important for a range of notable plants, butterflies and other insects. These grasslands are also important in providing insect food for resident and migrating birds.
Tall sward grassland is important for seed and insect production, small mammals and reptiles. These areas have particular benefits to birds of prey, including owls, and butterfly and moth species requiring tall sward grasses as part of their lifecycle.
Scrub on open grassland provides nesting space and cover for resident and migrating birds. Their root mats can provide reptile hibernation sites and cover for mammals.

Thus, the aims of the management will be to enhance the areas of grassland by reducing scrub and alien tree cover, whilst still maintaining some native scrub for resident and migrant birds.

2.2 Existing State

Generally, the WMA is rather degraded with few open species rich areas and considerable invading scrub. There are areas of disturbed ground with rubble, buried tyres etc.

Area A. In the north and east peripheral patches of largely non-native scrub dominated by Buddleia davidii and nettles Urtica dioica with a range of plants, mainly ruderals, at the edges including red bartsia Odontites verna, prickly sow-thistle, rib-wort Plantago lanceolata, red valerian Centranthus rubra and cocksfoot grass Dactylis glomerata and false oat grass Arrhenatherum elatius.

In places where the bare ground is not too disturbed a few calcareous grassland plants have established – sheeps fescue Festuca ovina, kidney vetch (a Dorset notable) Anthyllis vulneraria and wild carrot Daucus carota. These are too small to be of any ecological significance and just represent the willingness of this sort of land to support species-rich grasslands.

In the south-west and south-east is a border of scrubby woodland of predominantly Buddleia, sycamore Acer pseudoplatanus, bramble Rubus fruticosus agg. and bindweed Calystegia sepium with an edge of neutral grassland/scrub plants such as false oat grass agrimony Agrimonia eupatoria and enchanter’s nightshade Circaea lutetiana. The northern section is more open with bindweed, poppy Papaver rhoeas, bramble and teasel Dipsacus fullonum.

Area B is currently a grazed field.

Area C will be an attenuation pond within existing scrub and woodland. This will be created within the development as part of the proposed SuDs Management Plan (see later).

Ecological surveys and an assessment report (K. Cook, Bumpers Lane Ecology, 1-11-2012) highlighted a number of management issues. These and other ideas can be summarised as:

Protection of the western SNCI boundary against the development
Clearance of dumped materials and restoration
Control of alien plants: Buddleia davidii, sycamore Acer platanus, and Cotoneaster
Ongoing management of scrub and grassland
Management of the northern field and new bund and attenuation pond (see later) to increase species diversity
Control of and information for visitors

A management plan for the included part of the SNCI (Area A) was drawn up in October 2016 with a revision in October 2018. This revised plan now includes both the meadow in the north (Area B) and the Attenuation Pond (area C) in the south.

These areas are separated as a Landscape buffer zone (Area B) and a Wildlife Management Area (Area A) and the pond but will all be united within one Management Plan.

3. Management Plan Implementation

3.1 Time period

The Plan will have an initial period of capital works. In the schedule these have been separated into 3 years of capital/habitat establishment works but the works could be completed within Year 1 if this better suited the site managers.

After the initial capital works there is a revenue budget prepared that allows for the annual maintenance to continue for 30 years including Year 1 of the capital works.

3.2 Management Responsibility

For the purpose of this report no responsibility for the management is attached as this has yet to be decided. In the event that no arrangement is made between the site owners and a recognised Conservation body such as Butterfly Conservation and the Dorset Wildlife Trust, a dedicated management body is likely to be created to administer the works. This could be associated with the Isle of Portland Conservation Forum. The Dorset Wildlife Trust will continue to have an interest in the SNCI part of the site.

4. Management Plan, Schedule and Costs

4.1 General principles:

A buffer of scrub of approximately 2 metres deep will be kept along the boundary of the development
Scrub in Area A will initially be cut to 75% of the existing cover
All sycamore and Buddleia will be cut out at each location
All arisings will be removed off site
Stumps will be chemically treated immediately after cutting
Records of management will be kept by the managers for future reference by outside bodies.
The capital works of this plan can be executed in one year or be divided into 3 years.
After this period the site will be supported by an annual revenue fund for continuing maintenance

See Plan 2 below for site locations

Costs are shown where the activity is specifically related to habitat management and not part of the development costs and ecological mitigation. The latter are coded as DC.

4.2 Costed WMP and schedule

4.2.1 Capital works

Work is costed at £200 per man day to include administrative and other costs. Surplus funds can roll on to the following task/year.

NOTE: details of exact areas and what scrub to leave where will be worked up on an annual basis with the site contractor. Overall, 75% of the scrub will be removed, concentrating on the south facing areas first.

AREA A - WILDLIFE AREA

AREA B - Northern meadow

This area is owned by Stone Firms who wish to keep the existing grazing and grazing tenant therefore any conservation management of the field will have to be reviewed at a time when this agreement ends. A buffer strip between points 10a and 10b will be fenced off and planted with blackthorn Prunus spinosa scrub (2023 update - due to site and management difficulties this is no longer considered a viable option)

No grass cutting is proposed as currently the site is self-grazed by rabbits.

AREA C - Suds Attenuation Pond

The pond is to be constructed as part of the development costs. It will be finished with the planting already detailed in the SUDS plan so no capital costs are proposed. The soil surface around the sloping edge will be constructed of crushed stone and boulders. This surface will gradually vegetate with the natural vegetation of limestone but at first there will be a proliferation of ruderal plants benefitting from the fertile nature of the newly disturbed ground. This will be managed by annually cutting in late summer and removing the cuttings. Steadily the soil fertility will drop and plants characteristic of limestone will become established. As the inundation is only periodic and the porosity of the soil is high it is unlikely that any aquatic vegetation will establish.

NOTE: this conservation work is additional to the regular SuDs maintenance visits required as detailed in the SuDs Management Plan of February 2019.

The plan below has been taken from SUDs Management Plan February 2019. Note that this plan has its own separate annual maintenance regime associated with maintaining the integrity and operation of the site that is separate to this plan.

Small caption boxes are for construction purposes. Where relevant captions have been enlarged to provide ecological information.

4.2.2 Annual Maintenance Costs

4.2.3 Summary of Costs

Plan 2 follows

Approximate Management locations for guidance only as an aerial photograph (Courtesy Google Earth 2018), site conditions will dictate actual boundaries.