Guidance for the Management of Coastal Vegetated Shingle 
 
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Annex 03: Pagham Harbour 

 

Aerial view of Pagham Harbour (‘taken by Commission Air and supplied by West Sussex County Council)

Site Name: - Pagham Harbour Local Nature Reserve (LNR)

Protected Status: Site of Special Scientific Interest; Local Nature Reserve; SPA; Ramsar site; cSAC (Marine site)
Geographical location: Southern England
Local Planning Authority: West Sussex County Council
District: Chichester and Arun District Councils
OS Grid Reference: SZ 875 970
Area: 615.9 ha
Principle features/habitats: Shingle beaches and spits, saline lagoons, saltmarsh, rare plants and invertebrates; geomorphology; internationally important populations of over-wintering waterfowl

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Location

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Description

Pagham Harbour LNR comprises 1500 acres with many priority habitats, including two shingle spits that provide both coastal defence and important wildlife habitats. The Harbour is one of the few natural areas along an otherwise heavily built up West Sussex coastline.

This site comprises an extensive central area of saltmarsh and tidal mudflats with surrounding habitats including shingle, open water, reed swamp and wet permanent grassland. Pagham Spit is a good example of a fringing beach with the older parallel ridges and hollows supporting what are now thought to be the most important community of shingle lichens in West Sussex. The site also includes a series of saline lagoons, some of which were formed following the closure of a former harbour entrance.

Vegetated shingle is a nationally rare community. At Pagham, the type and extent of plant cover is dictated by the shifting nature of the substrates, the sea defence works, and by its relative exposure to the elements. In sheltered areas a diverse grass sward has developed with herbs such as early forget-me-not Myosotis ramosissima, biting stonecrop Sedum acre and the nationally endangered childing pink Petrorhagia nanteuilli, a species only found at two other minor sites in the UK. This contrasts with the sparse vegetation of the shingle ridge where the uncommon sea kale Crambe maritime and yellow vetch Vicia lutea are found. The site also provides a nesting area for little terns.

Pagham Harbour is a key site for coastal geomorphology. It is significant both as a classic shingle spit landform and for the links that have been demonstrated between the coastal near shore and offshore forms and sediments. The shingle spit system comprises a series of sub-parallel ridges and recurves, marking different phases of extension and frontal accretion. Shingle reaches the beach via the intertidal zone, and the so-called ‘Pagham delta’ and the behaviour of the spits and delta are intimately linked with water and sediment circulation around the Selsey peninsula.

The Nature Reserve is popular with local dog walkers and birdwatchers from many parts of the country, and attracts an estimated 100,000 visitors each year. The Reserve is a Site of Special Scientific Interest (SSSI), Special Protection Area (SPA), Ramsar site, and has recently qualified as a European Marine Site.    

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Site issues

 

Figure Pagham 01 Location of the main habitats and issues at Pagham Harbour LNR

Despite all the designations referred to above there are many threats to the vegetated shingle habitat including habitat loss due to urban encroachment, flood defence activities, proposed managed retreat / realignment of the southern spit, invasive garden escapes and visitor pressure. Figure (Pagham 01) below shows the location of the main issues affecting the site, derived from the oblique aerial photograph shown on the front page.  

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Urban encroachment and exotics

The site is subject to a considerable amount of encroachment: lawns and patio areas established over the shingle, boat ramps / hard standing linking properties with the shore. Garden escapes of exotics from bungalow gardens are much in evidence with many prostrate, mat-forming species, such as Cotoneaster covering the bare shingle (Figure Pagham 02 below). All alien plants and garden escapes (native or otherwise) were mapped in the summer of 2001. Of particular concern is the extent of snow-in-summer Cerastium tomentasum that threatens to over-run important lichen rich vegetated shingle communities supporting one of the main colonies of childing pink Petrorhagia nanteulii. The latter varies greatly in structure and size across the site, depending on local conditions and flowers from mid-June to September, but has been seen as early as May and as late as December.

Red valerian Centranthus ruber has also expanded dramatically in the last decade with the whole beach frontage above high water covered where once there were only a few plants. This will need to be controlled and gradually reduced in extent, but it should be noted that it could be providing a sheltered microclimate for the rare Toadflax Brocade larvae that feeds on both Common and Purple Toadflax.

 

Figure Pagham 02 Bungalows and exotics Cotoneaster spp. and Centranthus ruber encroaching on open vegetated shingle

The extent of alien species, along with childing pink, has been mapped with the help of volunteers, so this can be closely monitored in the future. The spread of red valerian over the last decade is also very evident. A list of the alien species encountered on the site is given below:

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Species List (native garden escapes bracketed)

Apple Malus domestica agg. Lavender Cotton Santolina chamaecyparissus Rose Campion Lychnis coronaria
Armenia sp. Lupin (Tree) Lupinus arboreus Rose of Sharon Hypericum calycinum
Baby’s Breath Gypsophila Mallow Lavatera sp. (Lavatera olbia) Rose Rosa sp.
Broad-leaved Everlasting-pea Lathyrus latifolia (Oak – Quercus robur) Rosemary
Broom (Spanish) Spartium junceum Opium Poppy Papaver somniferum Rue Galega officinalis
Buddleia Oxalis sp. Salix sp.
California Poppy Eschscholzia californica Oxeye Daisy Chrysanthemum leucanthemum Sempervivum sp.
Campion Silene sp. Oxyspermum sp. Senecio greyi (Brachyglottis monroi)
Chamomile Chaemomelum sp. Peony Paeonia Silver Ragwort Senecio cineraria
Cotoneaster (2 varieties) Periwinkle (Greater) Vinca major Snow in Summer Cerastium
Daisy Bellis sp. Pig Squeak Bergenia Soapwort Saponaria officinalis
Escallonia hybrids Privet (Garden) Ligustrum ovalifolium Snapdragon Antirrhinum
(Fennel Foeniculum vulgare) Purple Toadflax Linaria purpurea Tamarisk Tamarix gallica
Garlic Allium sp. Quaking Grass Briza maxima Thrift (cultivated variety) Armeria sp.
Geranium sp. Red Hot Poker (Traveller’s-joy Clematis vitalba)
Heather (non-native) Erica spp. Red Valerian Centranthus ruber Viburnum (hybrids)
Hebe Scrophulariaceae   Wallflower Cheiranthus
Hollyhock Alcea sp.   Weigelia (Floribunda and Florida sp. hybrids)
Iris (Bearded hybrids)    
Knapweed Centauria sp.    
Lavender Lavandula sp.    

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Pressure on rare species - little terns and childing pink

Harbour / inter-tidal areas: Little Terns require open bare shingle for nesting. The build up of vegetation can make a site unsuitable if left to develop. This is the case behind the southern spit on the area known as Tern Island, a remnant of an earlier more westerly spit alignment. This area had become over-run by sea couch, following the raising of the island to counteract erosion 10 years previously. In other areas this may be particularly acute where alien species colonise an area.

In 1991 ‘Tern Island’, a traditional nesting-ground due to its isolation from people and predators, was raised by 0.7m. This was in response to concerns over erosion and the potential risk of over-topping on the highest tides during winter storm conditions. The introduction of unclean ‘top-up’ shingle from the foreshore, incorporating sand and sediment, facilitated the rapid colonisation of ruderal vegetation and sea couch Elytrigia atherica, and the loss of species characteristic of the rare vegetated shingle habitat. The majority of open, bare shingle disappeared.

Pagham Spit Car Park / visitor management: Approaching the car park, rabbit damage is very much in evidence along with encroachment by Ivy. Both threaten to swamp childing pink colonies on the edge of the main track, which provides a circular walk around part of the shingle spit. The car park has been reduced to a size similar to parking facilities elsewhere on the Reserve to regulate visitor numbers. Current pressures included removal of shingle, (supporting important lichens) and plants (particularly yellow-horned poppy), dogs off leads disturbing nesting birds, dog fouling, fires and tipping of garden waste by local residents, vandalism of bird hides (Figure Pagham 03) and interpretation boards, and damage from motorbikes. Consideration is being given to the erection of both permanent and seasonal post and wire enclosures to protect ground nesting birds and rare lichen-rich communities and the prosecution of individuals breaking the Reserve’s bylaws, following extensive publicity.

 

Figure Pagham 03 Vandalism to bird hide

Pagham Lagoon: This important saline lagoon (Figure Pagham 04) is bounded on one side by a holiday village comprising permanent caravans & mobile homes. These provide a further source of pressure on the vegetated shingle habitat and better interpretation is needed to inform holidaymakers of the importance of the site.

Comment: Near the private estate of bungalows on Pagham Spit it is clear that the SSSI shingle has been damaged by fires and dumping of garden waste and building material. According to the warden there have been attempts at leaflet drops in the past organised by the landowner and English Nature to deter such activities. These have met with limited success.

 

Figure Pagham 04 Pagham Lagoon

 

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Erosion of the harbour entrance and southern spit (Church Norton)

Although the head of Pagham Spit has been secured by sheet piling, the southern spit is far less stable and subject to erosion, particularly on the seaward side (Figure Pagham 05 below). After severe winter storms the upper spit may be reduced to a width of 5m where groynes are present. This seaward side is replenished annually by the Environment Agency, who recycles enormous quantities of shingle from the foreshore over a two-month period, usually January/February. The Reserve liaises closely with EA to ensure stable vegetated areas are left untouched by the activity of machinery.

 

Figure Pagham 05 Erosion, Harbour outlet southern spit looking into the harbour

However, the deposited mixture of shingle, sand and silt often leaves an unforgiving substrate unsuitable for plant colonisation. Erosion is also self-evident at the end of the spit and on the harbour side, where an aerial photography marker and colonies of Childing Pink have been lost. Of great concern is a proposal submitted to DEFRA to allow the whole spit to roll back into the Harbour to form a more natural and sustainable line. To ensure that the integrity of the spit is maintained during this process it would be necessary to recharge the rear of the spit. This would in effect bury the Nature Reserve’s main childing pink colony along with most of the vegetation on the spit, as well as a strong colony of the Red Data Book snail Truncatella subcyclindric. The saltmarsh-shingle habitat interface would be lost, although this may be re-establish itself further back over a period of time, if and when the spit becomes stabilised and no longer needs replenishment. The intertidal area would also be reduced in size and it is not clear how this can be mitigated against. There are public fears that this proposal would open up the Harbour and threaten the inner sea wall that protects property and farmland at Sidlesham and Pagham.

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Erosion of the southern Shingle Spit at Pagham Harbour

The Harbour entrance, which lies between two shingle spits – Pagham to the north and Church Norton to the south, has changed its position on many occasions in the past. In recent times Pagham Spit has been stabilised by the establishment of a retaining wall at its southern end, although there is still scouring and erosion on the Harbour side that has been so pronounced that it will soon force the relocation of a bird hide in the vicinity (Figure Pagham 06). The northern end and harbour side of Church Norton Spit has also suffered from considerable erosion over the last few years, including the loss of valuable areas of vegetated shingle and an aerial photography marker used for coastline monitoring. At the same time there has been the rapid establishment of a new shingle island due west of the harbour entrance that is now supporting some pioneer plant species and has become an important roosting site for birds. It is hoped that as this accretes it will also attract breeding birds including Little Terns and other shingle specialists (see Figure Pagham 01).  

 

Figure Pagham 06 Erosion near the hide on the north spit

For the last 20 years or more the southern spit has been retained by a series of groynes and the replenishment of lost shingle for a period of at least 8 weeks between December and March. The Environment Agency, landowner of the intertidal area of the Harbour, currently undertakes this work. The shingle is dredged up from the foreshore area where it accumulates naturally and then deposited on the seaward side of the spit in order to prevent future breaches (the upper spit, which forms the main sea defence, can be eroded down to a width of 5m by winter storms).

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Corvid Control on Church Norton Spit and Tern Island

Corvid species can cause substantial damage to nesting bird colonies by taking eggs and young birds when the nests are not occupied by the adult. Control is effected through:

Shooting: Shooting is effective but can cause disturbance to nesting birds. Best to pinpoint corvid roosts and cull there.

Larson Traps: Larson Traps are particularly effective in the breeding season. However, they need regular checking and need to be well positioned out of public view.

Comment: Control of corvids is a sensitive issue with the public and reasons for control must be scientifically verified before commencing any control programme.

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Fox Control on Church Norton Spit

In the past foxes have been responsible for taking and disturbing a variety of ground-nesting birds As part of the protection of these species foxes have been controlled and the population kept to what is considered a sensible number, by:

Shooting: The only method that has been used is shooting between late July and late February. This is an effective method with little disturbance to other wildlife or the public if undertaken during the night or at dawn/dusk.

Gassing: Gassing is costly but effective and humane. However, it is very controversial and indiscriminate with the risk of affecting other mammals. It has not been used to date and is not recommended by the management committee

Comment: Control of foxes could be a sensitive issue with the public but it is common practise on surrounding land and while discrete has not caused public concern to date.  

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Managed realignment of the shingle spit

Proposals have been submitted to DEFRA (and approved in principle) for the managed roll back of the southern spit to a more sustainable and natural concave line that in the long term would also no longer require costly annual maintenance. Research undertaken by Southampton University indicates that if the spit were not maintained in its present form it would retreat back into the Harbour. Tern Island is a remnant of an earlier, more westerly alignment, although it is not thought that it would recede quite this far. The realignment would be achieved over a period of time by the recycling / feeding of shingle onto the Harbour side of the spit as it gradually moves in land, until such time as it has become stabilised. It is likely that the existing groynes would be removed, in part at least, on a piecemeal basis during the roll back. There is a view that the current line and slightly convex shape of the spit will make it prone to breaches in the future if no action is taken. An alternative may be to reduce the height of the spit by pushing shingle down from the main upper ridge onto the lower bank behind (harbour side) and then simply allow the spit to roll back gradually without any further replenishment.

In addition to the danger of opening up the Harbour to storm action and therefore the increased risk of breaching secondary sea defences (much of which consist of earth banks), there are also implications for the biological interests of the site. The most obvious of these is a slight reduction in the overall size of the intertidal area and the subsequent loss of some mudflat and saltmarsh habitats for wildfowl and waders. There will also be a loss of the long-established and sheltered interface between the shingle and saltmarsh habitats behind the spit, although this is likely to reestablish itself further back over time. The deposition of shingle onto the sheltered lower bank on the landward side of the spit during the roll back process would bury some of the best examples of stable undisturbed vegetated shingle in Sussex, in the short term at least. Recent surveys here have highlighted rare lichen and invertebrate communities, and a rare Red Data Book snail Truncatella subcyclindric associated with brackish strandline shingle, all of which could be lost. Church Norton Spit is also the location for the main colony of childing pink Petrorhagia nanteulii, perhaps the most important Red Data Book species to be found on the Reserve.

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Implications for the vegetation, childing pink and other rare species

As Childing Pink (an annual) has survived such a volatile and dynamic environment over the years with major physical changes to the Harbour coastline, it is likely that it will continue to colonise any new spit formation at Church Norton, especially if the re-alignment process is a gradual one. Old lichen communities and niche-dependant fauna may be less able to adapt to such changes. There is some evidence to suggest that shingle lichens (even rare ones) may become established on newly formed habitats relatively quickly, although it will take some time for any shingle to become sufficiently consolidated and stable enough to support extensive lichen rich turf communities.

The rare mollusc Truncatella subcyclindric may well be lost in the process. It is entirely absent from Pagham Spit and this could well be due to major shingle movement works here in the 1970s. Although there have been examples of the translocation of individual species of coastal plants with mixed success, conservation bodies have had little practical experience of large scale habitat re-location of this kind. The unstable nature of the habitat itself makes the intact removal of vegetated shingle turf almost impossible to achieve and there are no such case studies from which guidance can be taken. Even if this was possible there is still the issue of where to temporarily ‘house’ the most valuable vegetated shingle during the realignment process.

Of course it may be possible to translocate individual plants or to collect seeds for growing on and introducing back to the site at a later date, with the support of bodies such as the British Wild Plants Nursery in East Anglia. Seeds have already been collected from shingle plants on the Reserve during 2002 to assist with habitat creation projects in the area, notably at Selsey.

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The footpath issue

There is also the issue of public access to the site. Currently there is access along the foreshore at all times and along Church Norton Spit itself between August and March inclusive. The realignment of the spit, in addition to reducing the size of the Harbour, may also compromise the isolation of existing refuges, such as the two main shingle islands, and potentially increase disturbance to bird roosting and breeding areas. The degree of disturbance will depend upon the extent of the realignment

Comment: As with other sites where this has been proposed an Environmental Impact Statement may be required which will also have to deal with the issues of the footpath. Seasonal access along Church Norton Spit is part of the Reserve’s bylaws - there is no definitive public right of way/public footpath.

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Protecting breeding birds from disturbance

The public is excluded from the coastal spit to the south of the Harbour entrance from April to July inclusive to protect ground-nesting birds. Because this spit erodes during the winter and is subject to major reconstruction works before the end of March each year it is not possible to erect permanent fencing. Post and wire fencing and signage is therefore erected and removed each season. In the past there has been a caravan placed at the start of the spit that has been used as a wardening and monitoring base. Due to health and safety issues this has not been possible for the last two years. It is hoped that funding will soon be available for a seasonal warden, with main responsibility for the protection of breeding birds in the Harbour.

Pagham Spit to the north is an urban fringe site at the southern end of Pagham Parish and bordering Church Farm Holiday Village (Caravan Park). Popular with bird watchers, dog walkers, windsurfers and holiday makers it has become increasingly under pressure from visitors, to the extent that for several years now skylark, ringed plover and oystercatcher have failed to breed here. Apart from the ground-nesting bird interest, the site (like Church Norton Spit) is outstanding for shingle lichens, vegetated shingle communities, rare invertebrates and childing pink Petrorhagia nanteulii.

In spring 2002 it was agreed by the Reserve’s Scientific Steering Committee (including representation by English Nature, Environment Agency and Sussex Wildlife Trust), following concern by staff and the visiting public, that urgent action needed to be taken to protect the unique biodiversity of Pagham Shingle Spit. It was therefore proposed that before April 2003 permanent stock fencing, comprising round wooden posts and high-tensile wire netting (plus 2 strands of plain wire) to an overall height of 4 feet should be erected to protect the most important and vulnerable areas, including a saline lagoon. The ‘pig netting’ will be of a mesh size sufficient to exclude dogs of all sizes (dogs off leads is a major problem here). Temporary post and wire fencing will also be erected along the seaward side of the spit towards the beach, as and when birds establish nest sites here.

To ensure adequate public consultation the proposals have been published in the Pagham Beach Residents Association newsletters (Beach News), the Friend’s of Pagham Harbour newsletter (Harbour Views) and discussed at the Reserve’s Annual Liaison Meeting and the Friends AGM. Support has also been sought from the landowner, Pagham Beach (Holdings) Ltd. A sample 14 metre stretch of the exact fencing to be used has been erected just beyond the car park where people first access the site, to demonstrate exactly what the fencing will look like on the ground. The style of fencing has been carefully chosen for the location, to minimize the impact on the landscape and will still allow visitors to follow the normal circular walk around the spit.

The fencing totals 1200m and will cost around £5,000 to erect. Funding is being sought from the Reserve’s partner agencies and the Friend’s of Pagham Harbour. (A contingency fund may be required for repairs in response to vandalism.)

Efforts are also being made to improve information and interpretation around the site and in particular on land within or bordering the holiday village, to emphasise the importance of the site for nature conservation.

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Proposals for permanent fencing on Pagham Spit

Pagham Spit supports two internationally important habitats – vegetated shingle and saline lagoons. As a result it is home to communities of rare plants, lichens and invertebrates, many of which are the best examples in Sussex if not the UK. It also has the potential to support important populations of ground nesting birds such as ringed plover, oystercatcher and skylark, as it has done in the past. The latter has declined to such an extent in recent years that there is now a national action plan to protect and encourage suitable breeding areas.

The ever-increasing number of visitors to Pagham Spit is putting great pressure on both the flora and fauna of the site and has, in particular, led to the failure of ground nesting birds that are shingle specialists. The proposal is to erect permanent stock fencing around Little Lagoon and the bird hide, which will prevent disturbance from both people and dogs. Visitors will, as before, be able to take a circular walk around the spit and access the hide through a pedestrian gate during the winter months (see information notice details below).

The fencing has been carefully chosen for the location and will comprise of round wooden posts every 3-4 metres and straining posts where necessary, to which wire netting will be attached. Two strands of plain wire along the top will bring the height of the fence up to 4 ft. This specification has been chosen to provide maximum strength and protection while at the same time minimising the impact on the landscape. A sample stretch of fencing has been erected just south of the car park to demonstrate what the fencing will look like on the ground.

PAGHAM SPIT FENCING

PAGHAM SPIT SUPPORTS TWO INTERNATIONALLY IMPORTANT HABITATS – VEGETATED SHINGLE AND SALINE LAGOONS. AS A RESULT IT IS HOME TO RARE PLANTS, LICHENS AND INVERTEBRATES, & POTENTIALLY GROUND NESTING BIRDS SUCH AS SKYLARK, RINGED PLOVER & OYSTERCATCHER.

IN ORDER TO PROTECT THIS SPECIAL SITE FROM DISTURBANCE IT IS PROPOSED TO ERECT FENCING AS INDICATED ON THE PLAN BELOW. THE TYPE OF FENCING (AN EXAMPLE OF WHICH CAN BE SEEN HERE) HAS BEEN CHOSEN TO MINIMISE THE IMPACT ON THE LANDSCAPE WHILE STILL PROVIDING MAXIMUM PROTECTION FOR WILDLIFE.

WEST SUSSEX COUNTY COUNCIL

PAGHAM HARBOUR LOCAL NATURE RESERVE 01243 641508

**Update, February 2003: Postponement of permanent fencing - Following some local opposition to the fencing proposals (compounded by recent fencing programme on an adjacent part of the reserve) in spring 2003 the County Council will be requesting the public (and their dogs) to keep out of the sensitive areas by installing boundary markers and information boards. In parallel there will be a concerted effort to enforce bylaws, particularly across this part of the reserve, with prosecutions if necessary. If, through monitoring, these measures prove ineffective and the public refuse to co-operate, the fencing will proceed as specified during the winter of 2003/04 or soon thereafter.

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Controlling alien Plants/Garden Escapes

The problems associated with the invasion of a large number of aggressive alien species onto the shingle lead West Sussex County Council to grant-aid a project to establish the best method of controlling snow-in-summer. Trial plots will be either hand pulled, treated with herbicide or perhaps incinerated. However the control of ‘exotics’ was shown to be far from straight forward. The toadflax brocade moth (at its most westerly limit at Pagham) was found feeding on both common and purple toadflax early in the season. The native (common toadflax) is less frequently found and when it has been eaten by the larvae, the moth survives by eating the non-native purple toadflax. The larvae also appeared to do particularly well in areas sheltered by garden escapes such as buddleia and red valerian. It was noted that the latter had spread dramatically over the beach within the last decade.

All alien plants and garden escapes (native or otherwise) were mapped in the summer of 2001. Of particular concern is the extent of snow in summer Cerastium tomentosum that threatens to overrun important lichen rich vegetated shingle communities supporting one of the main colonies of childing pink Petrorhagia nanteulii. red valerian Centranthus ruber has also expanded dramatically in the last decade with the whole beach frontage above high water covered where once there were only a few plants. This will need to be controlled and gradually reduced in extent, but it should be noted that it could be providing a sheltered microclimate for the rare toadflax brocade larvae that feeds on both common and purple toadflax (see above). This also emphasises the value of some alien plants to the survival of some invertebrate species.

There are plans, in conjunction with English Nature, to determine the most effective way of controlling Cerastium by establishing trial plots / quadrats that will either be hand pulled or sprayed with herbicide. These will be compared to a control area where the plant will be left untouched. Once the methodology has been established and a clearance programme commences leaflets will be distributed to all Pagham Beach residents to make the case for selective vegetation control, and to forewarn them that work will be taking place immediately adjacent to their properties.

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Ragwort Control on Vegetated Shingle at Pagham Harbour LNR

Another problem, which has arisen, is from the invasion of ragwort. During 2002 Ragwort became well established for the first time on both shingle spits. The seriousness of the problem was not recognised until the latter half of the growing season, beyond the rosette stage, when control could only be partially successful. If left unchecked in future years it would greatly threaten the biodiversity of some of the best examples of vegetated shingle in Sussex.

In July 2002 any small plants that could be pulled with the root intact, without disturbing the shingle, were removed from the site. In this case disturbance could be almost entirely avoided by placing ones feet either side of the plant before pulling. Mature plants were then topped using a strimmer / brush cutter and the flowering heads removed. The remainder of the plant was then sprayed with Barrier H (Citronella Oil). However, because the near full-grown plants had little in the way of foliage there was inadequate surface area to properly absorb the Barrier H and many plants survived and even flowered again at the end of the season.   This methodology had the support of English Nature who, at the time had no formal advice for the control of ragwort on shingle. From 2003 onwards all areas of vegetated shingle will be surveyed for Ragwort rosettes in the early spring and autumn. Lesson: The spot spraying of rosettes with Barrier H via a knapsack is effective, non-toxic, avoids disturbance to the shingle from pulling (unless the plants are very small) and prevents disturbance by vehicles accessing the site to remove the plants once they have been pulled or cut. Although not cheap this is the quickest and least labour-intensive method available.

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Tern Island Restoration Project

At the end of September 2000 a major project was undertaken in an attempt to re-instate Pagham Harbour as a major breeding site for little terns, this species having last successfully bred in the Harbour during the mid-nineties (Figure Pagham 07).  

 

Pagham 07 Tern Island from the Church Norton Spit

This restoration project aimed to lower the centre of the island (approximately 75m long x 35m wide across the top, excluding the shoreline) by up to 0.2m. This would allow the island to be more influenced by sea spray and therefore inhibit the establishment of species untypical of vegetated shingle. The other key objective was to re-create and maintain a sizeable area of bare shingle for nesting terns, with a reshaped, well-profiled shoreline. Due to the fact that childing pink Petrorhagia nanteuilii had colonised the island (probably introduced during the 1991 operation) only two thirds of the island to the north and west could be completely cleared of vegetation.

Late September / early October was chosen as a relatively fair weather window, post breeding season but before the main influx of over-wintering wildfowl and waders, and at a time when the tides would be most favourable.

By mid - October 2000 the shoreline had been largely re-profiled and 9" of vegetation, topsoil and shingle stripped from two-thirds of the island. A 6" layer of clean shingle imported from a non-sensitive area of the spit was then deposited over a permeable membrane to ensure a largely weed free habitat for breeding Little Terns.

The remaining third of the island has been left due to the presence of a large colony of childing pink on more openly vegetated shingle. Immediately west of the harbour entrance shingle accretion has resulted in the formation of a new island / bank within a matter of years. The island has become colonised by pioneer plants and is becoming increasingly important as a roosting and nesting site. The Environment Agency has in the past dredged this area to maintain a clear channel out through the harbour mouth, but have recently discontinued this practice. It was suggested that this may be why the shingle on the harbour side of Pagham Spit had been gouged out in a crescent shape resulting in the under-cutting of the bird hide which only a few years earlier was at least 10m from the shoreline.

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Method

Working between the tides a ‘Himac’ tracked across the Harbour to the island on firm sand from the end of Church Norton Spit and scraped away up to 12" of vegetation, topsoil and shingle onto the shoreline. Over time this material would be naturally dispersed at high water. The edge of the island, previously a low ‘cliff’, was also re-profiled to provide a gently sloping shoreline (above a high water strandline of saltmarsh plants) on which terns could nest and up which they could retreat in the face of rising tides. The re-profiling would also provide terns with clear views of the whole island and any predators. A permeable membrane was then laid down before dumper trucks ferried clean shingle from a non-sensitive area of Church Norton Beach to the south of the spit and distributed it across the island to a depth of 4-6". Each day a shingle causeway was built up across the channel separating the spit from the intertidal mudflats and the island to provide safe, stable access for machinery. The causeway was partially washed away at every high tide.

 

Figure Pagham 08 Himac working on Tern Island

The operation took 10 successive days to complete due to the limited operational hours dictated by the tides and cost nearly £5,500. The project was funded by English Nature and the Environment Agency, and managed and supervised by West Sussex County Council.  

 

Figure Pagham 09 View of Tern Island from mainland bird hide.

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Follow-up

Following these works the island will receive minor weeding in the autumn and spring to keep the shingle clear of any plants other than sea kale, yellow-horned poppy, sea beat and saltmarsh / shoreline species that can provide useful shelter for tern chicks. A few plants have self-seeded above the membrane or actually grown up through it, but these are limited in number and easily removed by hand or treated with natural herbicide (Barrier H). Chick shelters (plastic piping 1m long x 0.2m diameter buried one-third into the shingle) have been installed around the island at 90 degrees to the prevailing wind. Although the island is now supporting increased numbers of breeding ringed plover and oystercatcher, little terns have not yet returned. In 2003 and 2004 decoys will be introduced, hopefully along with a solar generated loop-tape playing little tern calls. This combination has proved successful in the USA.

Comment: According to the warden, if and when the remaining childing pink is finally out-competed by invasive ruderal vegetation, consideration will be given to the restoration of the final third of the island. It is hoped that by this time childing pink may already have colonised the newly created open shingle habitat across much of the island.]

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Selsey Restoration

Following the damage caused to Selsey Bill during recent storm tides a decision was taken to initiate a programme of vegetation restoration. This included proposals for planting and sowing of native plants. Details of the planting programme are given below but further details are not yet available as the project is still in its infancy. In this location the shingle has a sandy matrix somewhat similar to that at Sizewell but precipitation levels are some 20% higher.

Background:

The species list for planting was drawn up using the Pagham Harbour LNR species list, the nearest vegetated shingle site. A planting density of 50 plants per 100m2 (as found at Church Norton spit, Pagham Harbour) was chosen as the main approach. The Sussex Botanical Recording Society was consulted as to any rare or local interest species at or near the site.

Specifications for planting and sowing

The detailed sowing and planting regimes are indicated below:

Sowing: (to be carried out prior to planting)

  • All seed to be of local source within West Sussex. Seed to be collected in the current growing season. (Note: all seed collected from the wild to be in accordance with English Nature consents).
  • All seed to be pre-treated to reduce germination response times (chitting, soaking etc.).
  • Sowing quantities approx. 0.5gm/m2 .
  • Mix seed thoroughly to ensure an even distribution of seed species.
  • Mix seed with coarse sand bulking material to 50gm/m2. Continue to mix frequently during application.
  • Broadcast seed on site in at least two transverse directions.
  • Lightly rake over or wash in between the shingle.

Planting:

  • All plants to be obtained from British Wild Flower Plants in Norfolk (Tel. 01603 716615) and grown from locally collected seed under contract.
  • Plants to be kept watered and maintained in healthy condition prior to planting.
  • Planting to take place in October/November 2002 or Feb/Mar 2003. Sufficient shingle to be locally removed to plant the plant just below its nursery level. Line the hole with 0.5kg coarse sand; tease out soil and roots from plant and place in hole. Backfill with shingle to just above the level of the soil.
  • If dry, water in, otherwise do not.
  • Plants must be regularly monitored in the first 4 – 6 weeks, during which time, water if necessary.

NB This project is still in the relatively early stage of development.

Species list and quantities for herbaceous plants:

    Sea kale Crambe maritima
    x 300
    Yellow horned poppy Glaucium flavum
    x 300
    Sea Campion Silene uniflora
    x 100
    Viper’s bugloss Echium vulgare
    x 100
    Biting stonecrop Sedum acre
    x 150
    Common toadflax Linaria vulgaris
    x 30
    Thrift Armeria maritima
    x 100
    Bittersweet Solanum dulcamara
    x 150
    Yellow kidney vetch Anthyllis vulneraria
    x 50
    Common bird’s foot trefoil Lotus corniculatus
    x 50
    Hare’s- foot clover Trifolium arvense
    x 50
    Orache Atriplex sp.
    x 20
    Maritime herb Robert Geranium robertianum ssp maritmum
    x 100

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    Lessons in restoration

    Pagham Harbour is a site which encapsulates many of the problems facing shingle management throughout the UK and the rest of Europe. It is a ‘relatively’ natural system hemmed in on its landward side by building and other human pressures. Managing these is a major part of the work of the Pagham Harbour LNR. More specifically the issues surrounding and the lesson learned from the following are relevant to other sites:

    • Control of alien species - the work on controlling individual species may be applicable elsewhere. This may be particularly important in relation to the use of chemical control as opposed to hand-weeding and the like;
    • Control of visitor pressure through the erection of permanent fencing even on a mobile spit. Value of local consultation;
    • Pros and cons of managed realignment; [This is dealt with as a discussion in relation to Cley-Salthouse Annex 07 (also part of the ‘Living with the Sea’ Guide "Coastal Habitat Restoration, towards good practice") and at Porlock (Annex 01).]
    • Introducing or re-introducing plants and seeds to regenerate vegetation. This could be very useful. Even though the work is just beginning the lessons learnt for here and Dungeness will be useful for many other sites.

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