6th European Conference on ECOLOGICAL RESTORATION 10 September 2008 | Ghent (Belgium)
Excursion Map Zeebrugge & Baai van Heist Uitkerkse Polders
Excursion ‘THE BAY OF HEIST’ Nature Reserve
(Knokke-Heist, West-Vlaanderen)
10 September, 2008
THE BAY OF HEIST NATURE RESERVE (Knokke-Heist, W. Vl.)
1. Short description of the area
1.1. name, municipality
Knokke-Heist, adjacent to Zeebrugge (prov. West-Vlaanderen)
1.2. biogeographical region
Eco-region of the Coastal dunes (Holocene)
1.3. management authority
Agency for Nature and Forest, Flemish Regional Authority (since 1997)
1.4. protection status
Natura 2000: - European ‘Habitat’-directive: SAC ‘BE2500001 Dune-sites including the IJzer-rivermouth and Zwin’ - European ‘Bird’-directive: SPA ‘BE2524317 Coastal nesting Birds at Zeebrugge-Heist’ Decree of 14 July 1993 on the protection of coastal dunes: protected dune-site Flemish Ecological Network: Large Nature Entity ‘104 The Bay of Heist, Sashul, Vuurtorenweiden and Kleiputten van Heist’ Flemish Regional Nature Reserve (ministerial orders of 22 Octobre 1997, 13 July 2000) Destination on the town and country - planning map: none (beaches were left blank).
1.5. ecological characteristics
soil type
Initially artificially raised beach by sand-suppletion: marine coarse sandy sediment with a large amount of shells, shell-fragments (lime) and shingles. After the initial suppletion, spontaneous sedimentation took and still takes place with deposition of essentially finer sand and silt. Low embryonic dunes formed by eolian transport of finer sand.
ecological key processes
High tides, 2 times in a period of 25 hours. Storms. Inundation by salt seawater of the higher zones at spring tides. Wind, eolian sand-transport. Some areas are influenced by seepage of fresh, lime-rich groundwater from the sand body against the dike.
historical information
The beach-plain was strongly enlarged by sand-suppletion and subsequently spontaneous sedimentation during and after the building of the 3 kilometer long eastern groyne of the harbour of Zeebrugge (1977 – 1983). The development of low dunes was locally initiated by the artificial planting of faggots but mainly occurred spontaneously, due to the natural establishment of Sand couch (Elymus farctus) on the site.
The impressive spontaneous development of embryonic dunes with Elymus farctus and of pioneer salt marsh vegetation with Suaeda maritime and Salicornia spp. on the silt-rich areas led to the designation of ‘The Bay of Heist’ as a Flemish Nature Reserve by ministerial order of 22 October 1997.
important nature values
‘The Bay of Heist’ is at the moment the only ‘Green Beach’ along the Flemish coast.
From the low tide-line to the foot of the sea-dike ‘The Bay of Heist’ shows at the present time the following pattern:
- a large tidal sandy beach with a slow slope and a rich benthos, especially strong Lanice-colony’s; - a strand-wall with a ridge of embryonic dunes with Elymus farctus and Honkenya peploides (habitat-type: 2110 embryonic shifting dunes) this natural dune-ridge is interrupted by a quite large tidal gully that was formed by a storm in December 2005; - a tidal inlet behind the embryonic dune-ridge on the strand-wall with a silt-rich soil and salt marsh vegetations with Salicornia div. spp., Suaeda maritima, Puccinellia div. spp., Spartina anglica, Obione portulacoides, Limonium vulgare, Spergularia media, Spergularia marina etc. (habitat-types: 1310 Salicornia and other annuals colonizing mud and sand, 1320 Spartina swards (Spartinion maritimae, 1330 Atlantic salt meadows (Glauco-Puccinellietaliae maritimae); - embryonic and more stabilized low dunes along the groyne of the Port of Zeebrugge and along the sea-dike of Heist; on the highest dunes, that are out of reach of the tides, a ‘grey dune‘– vegetation (habitat-type: *2130 Fixed coastal dunes with herbaceous vegetation) with Tortula ruralis var. ruraliformis immediately succeeded on the Elymus farctus - dominated vegetation. There is but few establishment of Ammophila arenaria (habitat-type 2120 Shifting dunes along the shoreline with Ammophila arenaria (‘white dunes’)). Euphorbia paralias and Eryngium maritimum are strongly present on the grey dunes as well as on the embryonic Elymus farctus – dunes; - the dunes along the sea-dike of Heist are literally veined with tidal gully’s that still are inundated by the seawater at spring tides; in these tidal gully’s in between the low dunes salt- and silt- depositions by the sea combined with fresh water seepage from the dunes offers the transitional environment appropriate for salt-tolerant vegetations with Parapholis strigosa, Catapodium marinum, Juncus maritimus, Triglochin maritima, Glaux maritima, Plantago coronopus, Apium graveolens, Aster tripolium, Trifolium fragiferum, Cochlearia danica, Sagina nodosa, Centaurium pulchellum, Centaurium littorale etc..
Since the nature reserve is not accessible for the public during the nesting season from the summer of 1998 on, the strand-wall of ‘The Bay of Heist’ has become an important nesting site for coastal bird species as Sterna albifrons, Charadrius hiaticula and Charadrius alexandrinus, although the last mentioned specie has been in decline for the last couple of years. In the dunes Galerida cristata, Anthus pratensis and Perdrix perdrix are among the regularly nesting species. Especially during the migration periods and in winter, ‘The Bay of Heist’ is also a foraging and resting site for Haematopus ostralegus, Numenius arquata, Numenius phaeopus, Limosa lapponica, Pluvialis squatarola, Calidris alba, Calidris alpina, Calidris canutus, Plectrophenax nivalis etc..
In the shallows in front of the beach of Heist a sandbank that emerges at low spring tide developed recently. This ‘mudflat and sandflat not covered by seawater at low tide’ is situated in a marine Special Protection Area in the frame of the European Bird Directive and partially in a marine reserve that both were designated by the Belgian federal authority.
important ecological constraints
The sportive and recreational use of the beach disturbs the nesting as well as the foraging or resting birds.
Indigenous as well as exotic invasive plant - species as Melilotus albus, Senecio inaequidens and Hippophae rhamnoides constitute a threat for the embryonic dune and ‘grey dune’ habitats. The same threat occurs for the salt marsh – habitats with the numerous appearance of the exotic salt-tolerant shrub Bacharis halimifolia, that escapes from nearby gardens.
Encroachment of the salt marsh and the transition-zones of the salt marsh and the dunes with Elymus athericus and Calamagrostis epigejos occurred locally for some years and leads to a loss of biodiversity.
Anthropogenic rubbish that is deposited by the tide pollutes the tide-mark.
1.6. ecological objectives for the area
A management-plan for the Flemish Nature Reserve ‘The Bay of Heist’ was approved by ministerial order of 13 July 2000. Although ‘The Bay of Heist’ has a rather limited superficies of 54 hectares and is situated between a sea-dike with flat-buildings and a harbour-groyne, the influence of the sea is so strong that the aim of that management – plan is to maintain the site as a ‘conducted natural entity’. The main management-actions are:
a) The regulation of the public access needs good means of signalling and a close-up surveillance in order to offer sufficient nesting-, foraging- and resting-opportunity for the birds: - during the nesting season of the birds only a 42 meter large zone at the foot of the sea-dike and a walking-path that, passing through the embryonic dunes and salt marsh, leads from the sea-dike to the recreational beach area outside the nature reserve are accessible for the public; - during the rest of the year the nature reserve is accessible only for pedestrians with the exception of two never accessible resting zones for birds: the central tidal inlet and an area of the tidal beach next to the groyne of Zeebrugge-harbour;
- the zone with a width of 42 meter at the foot of the sea-dike can the whole year be used for normal beach-recreation; in that zone a 12 meter large strip is delimited to allow the spontaneous development of (‘white dune’)-vegetation, elsewhere in that zone the dune-sand is annually levelled by the municipality to offer a flat and clean recreational sandy beach; - guided visits are organised quite often with the collaboration of the NGO Natuurpunt. b) The manual weeding of invasive species such as Melilotus albus, Senecio inaequidens and Hippophae rhamnoides on the dunes and of Bacharis halimifolia on the salt marsh and the transitional areas to maintain the dune and salt marsh- habitats. c) The mechanical mowing of the area’s that are encroached with Elymus athericus and Calamagrostis epigejos to maintain the habitats of salt marsh and of the transitional zones between salt marsh and dunes. d) The manual and selective beach-cleansing to remove the non-biodegradable anthropogenic rubbish in order to maintain natural tide-marks with its invertebrate fauna (amongst numerous others: Talitrus saltator) and the tide-mark vegetations with Cakile maritima, Salsola kali, Honckenya peploides, Atriplex glabriuscula and allow the development of new embryonic dunes with Elymus farctus. e) Every kind of fishing is prohibited within the Flemish Nature Reserve.
2. Stops during the excursion
See numbers on the aerial photograph on the next page (anno 2007)
1. Start of the excursion at the crossing of the sea-dike of Heist and the eastern groyne of Zeebrugge-harbour: explanation about the (quite recent) formation of the site and its main geomorphological pattern.
2. The place where the pipe of the initial sand-suppletion (1977 – 1983) discharged on the beach. A depression that until 1998 was a permanent tidal pool is still recognizable although the former pool got filled up with sediment, deposited by the sea. View on the central tidal inlet with salt marsh vegetations. Resting zone for coastal birds.
3. Second resting zone for coastal birds on the lower tidal sandy beach along the shoreline with Lanice - banks. Strong erosive area.
4. Main tidal gully through the strand-wall and its embryonic dune ridge. That tidal gully was formed during a storm in December 2005 and enlarged during the storms of the winter 2007 - 2008.
5. Contrast between the dune-vegetation in- and outside the nature reserve, due to the recreational trampling outside the nature reserve.
6. Along the walking path: tidal ‘veins’ (= gullies) through the embryonic dune- landscape with their halo-tolerant vegetations, the encroachment with Elymus athericus and the results of the mechanical mowing.
7. Main entrance of the reserve and free accessible recreational zone at the foot of the sea-dike, with a strip of 12 meter width for the spontaneous development of dune-vegetations under recreational use.
SER EXCURSION ‘DE BAAI VAN HEIST’ 2007
3
4 2
6 5
7 1 3. Annexes
3.1. Annex 1: Development of the site
3.2. Annex 2: Leaflet ‘Welcome to the ‘Bay of Heist’ nature reserve
1989 1996
Development of the site (1) 2000 2005
development of the site (1)
baai folder Engels 05-01-2007 09:16 Pagina 1
is the first step first the is orache Babington’s or sandwort sea wort,
VLIZ The Bay of Heist of Bay The
Agentschap voor Natuur en Bos en Natuur voor Agentschap sea rocket, prickly salt- prickly rocket, sea like plants of establishment The
annual) pioneer plant species which are washed ashore. washed are which species plant pioneer annual)
na and flora. and na
provide a seedbed for the germination of seeds of (often of seeds of germination the for seedbed a provide
habitats and wild fau- wild and habitats
as these floodmarks, after being covered up with sand, with up covered being after floodmarks, these as
servation of natural of servation
. This is quite fortunate, quite is This . ’ Heist of Bay The ‘ at not but away,
Directive on the con- the on Directive
is cleared is ’ floodmark ‘ this beaches Flemish most On line.
under the European the under
driftwood and lumps of peat forms along the high-water the along forms peat of lumps and driftwood
conservation area conservation
resting zones are shown on the map. the on shown are zones resting
A deposit belt of seaweed clusters, shells, bird carcasses, bird shells, clusters, seaweed of belt deposit A
designated a special a designated
exception of the bird resting zones. The footpaths and footpaths The zones. resting bird the of exception
A I F D CTION N ORMATION UNE
was ’ Heist of Bay The ‘ free to roam anywhere in the nature reserve, with the with reserve, nature the in anywhere roam to free
– scale international
along the groyne. Outside the breeding season walkers are walkers season breeding the Outside groyne. the along
Pioneer salt marsh vegetation: annual seablite and glasswort and seablite annual vegetation: marsh salt Pioneer
kind anywhere on the Flemish coast, or indeed even on an on even indeed or coast, Flemish the on anywhere kind must keep to the central footpath and the boardwalk the and footpath central the to keep must
the only examples of their of examples only the – communities biotic rare very of 31 July), visitors July), 31 – April (1 season breeding the During
as a Flemish nature reserve. Because of the presence the of Because reserve. nature Flemish a as ’ Heist
The Bay of Bay The ‘ designated Decree Ministerial a 1997 October • DO NOT SET UP WINDSHIELDS OR PARASOLS OR WINDSHIELDS UP SET NOT DO •
under the Dunes Decree, then on 22 on then Decree, Dunes the under ’ area dune protected ‘ • MOTOR VEHICLES PROHIBITED VEHICLES MOTOR •
Flemish Government decree designated most of the beach a beach the of most designated decree Government Flemish • DO NOT MAKE NOISE MAKE NOT DO •
grow and natural dunes to form. On 4 October 1995 a 1995 October 4 On form. to dunes natural and grow • DOGS ARE NOT ADMITTED NOT ARE DOGS •
trampling, which enabled pioneer plants to germinate and germinate to plants pioneer enabled which trampling, • DO NOT DIG HOLES DIG NOT DO •
seaside visitor. A lower level of recreational use meant less meant use recreational of level lower A visitor. seaside • DO NOT DROP LITTER DROP NOT DO •
of this broadened beach proved unattractive to the average the to unattractive proved beach broadened this of • DO NOT LIGHT FIRES LIGHT NOT DO •
sand ’ muddy ‘ the and sea the to distance long relatively the • KEEP TO THE PATHS THE TO KEEP •
of silt and sand in this sheltered area. Right from the start, the from Right area. sheltered this in sand and silt of • DO NOT DISTURB ANIMALS DISTURB NOT DO •
Zeebrugge (1977-1985) and the partially natural deposition natural partially the and (1977-1985) Zeebrugge • DO NOT PICK OR DAMAGE PLANTS DAMAGE OR PICK NOT DO •
of the construction of the eastern groyne of the port of port the of groyne eastern the of construction the of
. This is an unintended beneficial consequence beneficial unintended an is This . ’ beach green ‘ a conduct:
flats and salt marshes, a landscape-type that scientists call scientists that landscape-type a marshes, salt and flats wildlife, we ask visitors to abide by the following code of code following the by abide to visitors ask we wildlife,
plain, consisting of more than 50 ha of beach, dunes, mud dunes, beach, of ha 50 than more of consisting plain, reserve are very fragile. In order to protect this valuable this protect to order In fragile. very are reserve
dune formation has started again in this sub-area. this in again started has formation dune
a very narrow foreshore, but now it shows a broad shore- broad a shows it now but foreshore, narrow very a nature ’ Heist of Bay The ‘ in fauna and flora The entrances.
However, this was by no means the end of the evolution, as evolution, the of end the means no by was this However,
rein is given to nature. In the early seventies Heist-West had Heist-West seventies early the In nature. to given is rein public access to the nature reserve are displayed at the at displayed are reserve nature the to access public
. ’ ‘kille or foreshore wet bare, a to reduced and off rubbed
mechanical beach cleansing, but in this part of Heist free Heist of part this in but cleansing, beach mechanical tion on nature conversation. The main rules governing rules main The conversation. nature on tion
central sand ridge, a large part of the salt marsh was marsh salt the of part large a ridge, sand central
grow is immediately trampled underfoot or destroyed by destroyed or underfoot trampled immediately is grow in accordance with Flemish and European legisla- European and Flemish with accordance in ’ Forests
broke through the through broke ‘mui’ or tideway new a tides, storm of
other beach along the Flemish coast, any plant trying to trying plant any coast, Flemish the along beach other Agency for Nature and Nature for Agency ‘ the by managed is reserve nature
. When, in the autumn of 2001, as a consequence a as 2001, of autumn the in When, . purslane
nature reserve! On any On reserve! nature ’ Heist of Bay The ‘ visit must really animals (including fish and worms) or to destroy nests. This nests. destroy to or worms) and fish (including animals
sea and cord-grass grass, meadow sea up, higher and,
line? Vast, monotonous stretches of sandy beach? If so, you so, If beach? sandy of stretches monotonous Vast, line? the peace, to practise sports or play games, to trap or kill or trap to games, play or sports practise to peace, the
glasswort of species two , seablite annual including zwin,
What jumps to mind when you think of the Flemish coast- Flemish the of think you when mind to jumps What In every Flemish nature reserve it is forbidden to disturb to forbidden is it reserve nature Flemish every In
vegetation developed in this muddy this in developed vegetation marsh salt Halophytic
S R ITUATION EGULATIONS
the summer of 2001 not far from the Heldenplein. the from far not 2001 of summer the
joined up with the sea during sea the with up joined – ‘zwin’ a as Dutch in known
– channel tidal elongated This reserve. the of part tral
Hazegraspolder
0020 004000 3000 2000 1000 5000 m 5000 0
behind this sand ridge in and out of the basin-shaped cen- basin-shaped the of out and in ridge sand this behind
11 Inner dunes of the old old the of dunes Inner 11 België
the spring high tide, the sea flowed with varying intensity varying with flowed sea the tide, high spring the
0Blinkaartbos 10
N
RAMSKAPELLE
siderably between 1998 and the autumn of 2001. During 2001. of autumn the and 1998 between siderably
BLANKENBERGE Panne) Panne) WESTKAPELLE
6
as the seaward side. This sand ridge increased in heigt con- heigt in increased ridge sand This side. seaward the as 1
9 Golf course (Brabantse (Brabantse course Golf 9
ZEEBRUGGE
5
east to west, with intertidal beach to the landward as well as landward the to beach intertidal with west, to east 15
8 Park 58 Park 8
Nederland
3
4 HEIST sand ridge stretches out straight across the beach, from beach, the across straight out stretches ridge sand
Willemspark 7
7 8 11
2
which is continously being fashioned by sea and wind. A wind. and sea by fashioned being continously is which 9
10
Palingpotweiden 6 RETRANCHEMENT
14
KNOKKE
is a very dynamic and variable landscape variable and dynamic very a is ’ Heist of Bay The ‘
HEIST
16 Verdronken zwarte polder zwarte Verdronken 16 5 Kleiputten van Heist van Kleiputten 5 12 KNOKKE-
M ARSHES 13
15 Reygaertsvliet (De Vrede) (De Reygaertsvliet 15 Vuurtorenweiden 4
CADZAND
S A T S ALT ND ND IDEWAYS IDEWAYS HORELINE, HORELINE, 4Dievegat 14 Sashul 3
3Zwin 13 ’ Heist of Bay The ‘ 2
CADZAND-BAD
oordzee N NIEUWVLIET-BAD
R
ESERVE
2Zwinbosjes 12 Fonteintjes 1
16
N O T ATURE ’ HEIST F BAY HE NATURE AREAS BETWEEN BLANKENBERGE AND BRESKENS AND BLANKENBERGE BETWEEN AREAS NATURE
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MORE INFORMATION towards the formation of a new dune. This vegetation acts Koen Maréchal, Warden of the reserve as a sand trap, which gives new species like sea couch a GSM: (0479)89.01.05 chance to establish themselves.
Agency for Nature and Forests Coastal Zone Cell Zandstraat 255 8200 Sint-Andries (Brugge) tel: (050) 45.42.49 fax: (050) 45.41.75 WELCOME Sea sandwort WELCOME Sea couch is a very special type of grass: it tolerates salt The Agency for Nature and Forests is responsable for the water and does not stop growing when covered with sand. TOTO ‘THE‘THE BAYBAY OFOF HEIST’HEIST’ preparation and implementation of Flemish nature policies Because of this sand-fixing ability sea couch is a vital link and the management of nature reserves owned by the in natural dune formation. When these ‘embryonic dunes’ NATURENATURE RESERVERESERVE Flemish Region. The Agency for Nature and Forests also pro- or ‘low sea couch dunes’ subsist and continue to grow, vides financial assistance for the purchase and management fresh water, originating from precipitation, starts to accu- of land by recognised nature associations. mulate in the sandy dune. Once the dune has grown to such an extent that the plant roots are out of the reach of the salty seawater, the vitality of sea couch decreases, thus enabling another type of grass – marram – to grow. However, this depends on there being a sufficient supply of fresh sand, which is no longer the case in the larger part of ‘The Bay of Heist’. Where dead stalks of sea couch or mar- ram are covered with sand, fungi like the charming Psathyrella ammophila grow. Here also scanty, low, mossy and herbaceous vegetation may develop: the grey dune. Besides typically low flora such as biting stonecrop, little mouse-ear, dark-green mouse-ear, rue-leaved saxifrage and striated catchfly, stronger plants also develop in the Agentschap voor Natuur en Bos dune, such as sea holly, sea spurge – a southern species Caterpillars of the cinnabar Twisted moss Sea buckthorn baai folder Engels 05-01-2007 09:16 Pagina 2
Flemish nature reserve ‘The Bay of Heist’
which is here at the northernmost point of its distribution range – pale goat’s beard, beaked hawk’s beard and the maritime variety of perennial sow-thistle.
At storm and spring tide seawater penetrates far into the dune, and between two high tides a salt crust may occur on the soil of these small tidal inlets. Elsewhere one might find rust spots, indicating a seepage of freshwater from the dune. In this particular environment – with alternating Zeebrugge eastern groyne fresh- and saltwater, humidity and drought – a special Noordzee salt-tolerant vegetation thrives, with species such as buck’s-horn plantain, Danish scurvy-grass, sea plantain, sea arrow-grass, wild celery, lesser sea spurrey, common centaury, knotted pearlwort, sea milkwort, hard-grass, sea fern-grass, and the most eyecatching insect-tempter of late summer, sea aster.
Posts 1 lo w- Annual seablite Sea aster wat er li ne n auti cal ch BIRDS OF THE BAY arts
Each type of vegetation attracts very specific animals. The buoys dunes are the breeding place and habitat of several endan- gered songbird species, such as the crested lark, the meadow pipit – regularly demonstrating its parachute-like flight – and the Northern wheatear, a nice small Turdidae which breeds in rabbit-holes. The partridge (dune) and the shore post lark (high-water mark and salt marsh) find an ideal biotope here; and where the top of the beach is littered median high-water line with a layer of shells, the Kentish plover, the great ringed Posts plover and little tern feel on top of the world. The rarity of Western boardwalk this type of habitat is also the reason why these species are endangered at international level and deserve to get a chance in ‘The Bay of Heist’, where they have all started to breed in varying numbers. The Kentish plovers find their central footpath food in the muddy ‘zwins’ and in the surf. During the win- ter half-year they migrate to warmer climes and are Zeedijk replaced by sanderling, dunlin and grey plover. The dark- bellied Brent goose is a regular winter visitor. Bird species Vissershuldeplein with a year-round presence are the oystercatcher, com- Elisabethlaan mon redshank and common shellduck. Like the Northern wheatear, the common shellduck breeds in rabbit burrows. Whereas plovers find their food (small crustaceans and insects) by sight, the oystercatcher uses its long beak to probe sand and silt for bivalve molluscs such as cockles
and shells or lugworms. Barnse vaartje3 Heistlaan N
0 100 200 m 2 0 200 400 m
LegendL EGENDE Entrance/InformationEntrance/I nformation water/sea wet pasturepasture Parking wet beachbeach bird restingresting z onezone year year-round -round
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Main roadroad LighthouseLighth ouse mud !at flat a ndand salt salt marsh marsh willow woodland woodland
brushw ood grey dunedune and and dune dune pasture pasture LimitLimit ofof the the reser reserve ve 1 TheThe BayBay ofof Heist Heist’’ Flemish Flemish natur nature e reser reserve ve brushwood De Sashul’ regional nature reserve urban area area trampledtrampled v egetationvegetation FenceFen ce 2 De Sashul’ regional nature reser ve
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Little tern Kentish plover ALIVING BEACH MANAGEMENT The dunes, mud flats and salt marshes and the transition which only occur in comparable densities in the neighbourhood of The management plan for ‘The Bay of Heist’ nature reserve zone between salt marshes and dunes ar not the only very Bray-Dunes (France). The common brown shrimp, Corophium (amphi- was drawn up by the Department of Biology of the special areas of ‘The Bay of Heist’. The wet portion of the pod) and various even rarer species of shrimp also occur in large num- University of Ghent and approved by ministerial decree of beach and the lowest part that is flooded by the sea for bers. This abundant food supply attracts a lot of water- and seabirds, 13 July 2000. Up to now nature management has been most of the year also support a very particular fauna. Large such as the common tern, sandwich tern and little tern in summer, the restricted to the maintenance of tranquillity, the preven- colonies of Pygospio elegans, Spio filicornis and great crested grebe, common eider and red-breasted merganser du- tion of damage to vegetation, the removal of brushwood Spiophanes bombyx thrive at the low-water line. This part ring the winter half-year, and the great cormorant all year round. The branches along the eastern groyne and the elimination of of the beach and the shallow sea adjoining ‘The Bay of common seal and the grey seal are regulary seen off ‘The Bay of Heist’, white melilot, an invasive green manure crop. The narrow- Heist’ are an important spawning and nursery area for and the common seal occasionally takes a rest along the coastline. leaved ragwort, another exotic plant, originating from many fish species such as sandeel, plaice and flounder, Southern Africa, is now being removed. In the future, eco- logical engineering measures could be taken to preserve some biotopes containing extremely rare animal species. The management of ‘The Bay of Heist’ will have to conti- nously adapt to a very dynamic natural environment, the beach!
Lugworm Oystercatchers
EVOLUTION AND STATUS OF COASTAL BREEDERS IN THE ZEEBRUGGE PORT AREA
Eric WM Stienen & Wouter Courtens
Copyright Jan van de Kam
Research Institute for Nature and Forest Kliniekstraat 25 1070 Brussels Belgium
The Zeebrugge port area; importance for coastal breeding birds
With the development of the outer port of Zeebrugge vast areas of sandy, scarcely vegetated and relatively undisturbed land were created offering suitable nesting habitat for coastal breeding birds. After the first sand suppletion (finished in 1984) pioneer species like Little Tern Sterna albifrons and Kentish Plover Charadrius alexandrius settled in the area in 1985. At first the vegetation developed slowly and breeding birds reacted reluctantly, but from 1988 onwards the area attracted increasing numbers of plovers, terns and gulls. During the next 20 years the area underwent major changes. Suitable nesting habitats were claimed for the development of buildings, car parks, roads and railways, while ongoing raising of land created new nesting opportunities. In areas that remained more or less undisturbed, Herring Larus argentatus and Lesser Black-backed Gull L. graellsii displaced pioneer species as the succession of the vegetation progressed. To ensure nesting of pioneer species management measures were taken, like regular removal of the vegetation and covering areas with shell fragments. The radical changes (raising of land, industrial development and nature management) caused strong and sudden fluctuations in the population size of true pioneer species, while slow processes like succession of the vegetation, competition for nesting habitat and recruitment of young seem to attribute more to the population dynamics of gulls and Common Terns S. hirundo.
Compensation measures
In 2000, a small ‘tern peninsula’ (2 ha) was created along the eastern breakwater of the Zeebrugge harbour as a compensation for the loss of nesting habitat for terns in the port area. The peninsula was enlarged to about 10 ha just before the onset of the breeding season in 2002. In order to offer suitable nesting habitats to the different species, the peninsula had to meet several ecological conditions. In general, all tern species concerned nest in highly dynamic and sparsely vegetated habitats that are free from ground predators and disturbance by humans. In natural habitats, succession of the vegetation is restricted through the influence of salt water (salt spray and regular flooding during winter) and through processes of erosion and accretion. At artificial nesting sites like the ‘tern peninsula’, management of the vegetation is often necessary. All species further require a flat, sandy area in the vicinity of the breeding grounds and adjacent to open water for courtship and roosting. Finally, there must be suitable feeding grounds in the vicinity of the colony site, but given the successful occupation of the harbour area in the 1980s and 1990s as well as the high reproductive rate of the terns and gulls nesting in Zeebruge this condition is fully met.
Although there are some general similarities in nesting habitat, the different tern species occupy their own specific breeding niche and require specific ecological conditions. Little Terns are true pioneers that prefer bare sand, gravel or shell material for nesting. They build their nest close to the high-water mark and do not appreciate the presence of gulls. Common Terns prefer sparsely vegetated habitats that are situated somewhat higher above the high-water mark, while Sandwich Terns choose the highest parts. The latter species further requires the presence of nesting Black-headed Gulls. As Sandwich Terns are non-aggressive against intruders they depend on nearby nesting gulls to chase away predators. In term, Black-headed Gulls generally breed in more densely and higher vegetated habitats than terns. So in order to attract all these species the peninsula had to offer a natural succession series from non-vegetated lower areas, via sparsely vegetated, to partly vegetated higher areas ( as well as a sandy area for roosting and courtship situated adjacent to the water. In order to make the lower parts of the peninsula suitable for Little Terns the sand was covered with a 5 cm layer of shell material. To minimize erosion and to support quick colonization by Black-headed Gulls the higher parts were implanted with salt-resistant grasses. Most parts of the peninsula were not implanted because earlier experience in raised terrain showed that the area will become suitable for Common Terns within 2-3 years. No specific measures were taken to attract plovers (Kentish and Ringed Plover Charadrius hiaticula) because it was assumed that the parts developed for Little Terns were also suitable for those species.
Sandwich Tern Common Tern Little Tern Black-headed Gull
High-water mark
layer of shell material natural growth of Biestarwe and vegetation; no implanting
Figure 1. Each species occupies a specific part of the peninsula.
Status of terns and plovers
The port of Zeebrugge and the adjacent nature reserve Baai van Heist harbour 2 species of plovers, 5 species of gulls and 3 species of terns. Apart from Herring Gull, all these species are listed on the Red list of threatened birds in Flanders. Furthermore most species are listed on important European instruments for the protection of birds such as EC-Bird Directive on the conservation of wild birds (EC- BD), the Bern Convention on the conservation of European wildlife and natural habitats and the Bonn Convention on the conservation of migratory species of wild animals.
Table 1. Importance of the Zeebrugge population of coastal birds.
Species Maximum Proportion of EC- Bern Bonn number of total population BD pairs
Ringed Plover Charadrius hiaticula 10 < 0.1% II II Kentish Plover Charadrius alexandrius 114 0.3% II II Mediterranean Gull Larus melanochepalus 90 < 0.1% I II II Black-headed Gull Larus ridibundus 2390 0.1% Common Gull Larus canus 24 < 0.1% Lesser Black-backed Gull Larus graellsii 4573 2.6% Herring Gull Larus argentatus 1986 0.2% Sandwich Tern Sterna sandvicensis 4076 7.2% I II II Common Tern Sterna hirundo 3052 4.8% I II Little Tern Sterna albifrons 425 3.8% I II II
Throughout the world coastal breeders have decreased heavily in numbers. Breeding habitats of many species are threatened by human activities like recreation, port expanding and works for coastal defence. As a result of these activities the suitable breeding habitat for these species has been strongly declined. Therefore these birds seek more and more artificial nesting sites like roof tops and harbour plains to nestle. Zeebrugge is such an artificial site that is, however, extremely important for the population as a whole (Table 1). Of Lesser Black-backed Gull, Little Tern, Common Tern and Sandwich Tern more than 1% of the total biogeographical population breeds in Zeebrugge. Peak numbers of Sandwich Tern even exceed 7% of the total population. However in pioneer species like these numbers can heavily fluctuate depending on local feeding conditions, the presence of predators, the presence of suitable nesting sites, vegetation height etc. Such fluctuations are very typical Sandwich Tern for example. Birds nesting in Zeebrugge in a certain year may move to the Netherlands in the next year and back again the year thereafter.
Little Tern Common Tern Sandwich Tern
450 3500 4500 400 3000 4000 350 3500 2500 300 3000 250 2000 2500 200 1500 2000 N pairs N Pairs N pairs 150 1500 1000 100 1000 50 500 500 0 0 0 1985 1989 1993 1997 2001 2005 1985 1989 1993 1997 2001 2005 1985 1989 1993 1997 2001 2005
Figure 2. Numbers heavily fluctuated during the past 23 years.
Future perspective
Although the ‘tern peninsula’ was highly successful in terms of attracting large numbers of terns and in terms of breeding success, there are some drawbacks in building nature for coastal breeders. Regular removal of the vegetation in the higher parts and suppletion with shell material in the lower parts will be necessary. Predators like rats, foxes and wild cats must be controlled in order to keep the peninsula suitable for nesting. But given that this one of Europe’s most important and most productive tern colonies such is certainly worthwhile.
Excursion Uitkerkse Polder Nature Reserve
(Blankenberge, De Haan, Zuienkerke, West-Vlaanderen)
10 September, 2008
Blankenberge
Wenduine
Brugge
UITKERKSE POLDER NATURE RESERVE (BLANKENERGE, DE HAAN, ZUIENKERKE, W. Vl.)
1. Short description of the area
1.1. name, municipality
Blankenberge, De Haan en Zuienkerke (prov. West-Vlaanderen)
1.2. biogeographical region
Flemish ‘polders’: clay area (quaternary period) with high human influence
1.3. management authority
Natuurpunt (since 1989)
1.4. protection status
Natura 2000 (SPA: Polder complex, SAC: partial); mostly nature zone on physical, planning map and partly agricultural area; designated in the Flemish Ecological Network, situated in a protected landscape, acknowledged private nature reserve; supported by LIFE-funding and the Flemish Government.
1.5. ecological characteristics
soil type
quaternary clay soils, originated by marine deposition, resting on a layer of peat who contains salt; locally surfacing of salty peat or sand; gradients in salinity and in humidity.
ecological key processes
the core areas are influenced by seepage of salty water from the sea and the salty soil, without intertidal holdings. small ditches covers the whole area.
historical information
The reserve is a rare and intact poldercomplex at the Flemish coast. The Flemish east coast was once comparable with the present Wadden Shallows in Holland, Germany and Denmark. The mud-flat was situated after a dune-belt and beach-coast. Because of the enclosing of the dune-belt and beach-coast between 6000 and 4200 BP this mud-flat changed into a peat bog.
Since 2800 BP, the sea affected the peat and developed salt marshes. The incursion of the northsea changed again the peat bog into an intertidal area with mud-flats and creeks and channels. The first settlements occurred, but were regularly destroyed. Since 1000 AD people started to impolder on a small scale
1 The salt marshes are ever since used as salt meadows.
Together with the growing of the medieval city Brugge, people start with small-scale digging of peat for fuel and salt. This digging continued from 1200 Ad until the 20th Century and caused a micro-relief. This small-scale micro-relief due to the digging, together with the sometimes medieval parcel structure of the salty meadows and location of the ditches, is still visible.
Since the middle of the 20th century, a lot of grasslands became intensively used by farmers, changed in arable fields or the micro-relief got destroyed. important nature values
Halophilous habitats are a very rare and vulnerable habitat within the whole European Union, mostly confined to estuaries. However, in the polders along the eastern Flemish coast, and at the 'Uitkerkse Polder' especially, salt meadows also occur outside the intertidal holdings.
Because of the influence by seepage of seawater and/or high concentrations of historical salt in the peat, there established a very typical 'shore like' habitat: species of dynamic and salty shores are missing, but rare and vulnerable 'brackish' species such as Salicornia europaea, Suaeda maritima, Parapholis strigosa, Aster tripolium, Glaux maritime, 4 kinds of Puccinellia sp. and Spergularia marima. They grow together with typical polder species like Trifolium fragiferum, Cynosurus cristatus and Hordeum secalinum and heathland species like Carex disticha and Lychnis flos- cuculi.
Therefore, the salt meadows, Salicornia-vegetations and Glauco-Puccinellietalia, at the Uitkerkse Polder can be considered as a geographically unique variety of the halophilous habitats in the European Union.
These salt meadows, characterised by their relief, are also a favourable breeding spot for Annex I species like Recurvirostra avosetta, Luscinia svecica, Sterna hirundo, Circus aeruginosus. The Uitkerkse Polder is of European importance for migrating birds such as Platalea leucorodia, Philomachus pugnax, Limosa limosa and Pluvialis apricaria. Perhaps, the project area is most known as an outstanding wintering area for thousands of waders, geese and ducks.
Among them is the Anser brachyrhynchus: 90% of the entire Western population (Svalbard-population) winters in the Uitkerkse Polder. They strongly depend on the grasslands as feeding area. For several waterbird species the project area holds more than 1% of the world population (Ramsar criteria). important ecological constraints
The habitats are highly threatened by the recent developments and intensification of modern agriculture. On a increasing scale, the wet grasslands are drained, excessively manured, transformed into fields, and/or their microrelief destroyed. Watermanagement is still rejected on agriculture. So, the presence of the unique and vulnerable habitats and their associated species are more and more limited to the present-day nature reserve, which are managed by Natuurpunt vzw.
Helicopters, planes, roar of guns against birds, recently disturb. the wintering geese and breeding birds.
2 The increased pressure for building sites, camp sites, tourist infrastructure, … is a slumbering problem.
Finding an equilibrium between tourism and nature conservation is an important challenge.
1.6. ecological objectives for the area
Large scale restoration of the unique salt meadows, concerning Salicornia- vegetations and Glauco-Puccinellietalia and their associated breeding species like Recurvirostra avosetta, Sterna hirundo, Circus cyaneus, Platalea leucorodia and Luscinia svecica.
Restoring an inshore variety of 'Kreken' (large shallow inlets and bays), Magnopotamion habitats, grey dunes and Calthion/Arrhentherion meadows as well. All are almost or completely disapeared nowadays.
Creating outstanding migrating, foraging and/or wintering conditions for species like Anser Brachyrhynchus, Anser albifrons, Platalea leucorodia, Asio flammeus, Pluvialis apricaria, Philomachus pugnax, Limosa limosa.
Promoting and developing nature oriented tourism to ensure the social and economical embedment of Natura 2000.
2. Management/restoration objectives and techniques the production of necessary management schemes and a monitoring survey of the results the acquisition of land in order to restore halophilous grasslands large scale restoration of salt meadows, extending of the existing ‘core areas’ and creation of new ones starting up recurring management (grazing management, hayfields) to obtain the optimal development and management of salt meadows and hay meadows and theis associated species the development and realization of an broad program to develop the socio-economic potentials of the project area by means of our enlarged and re-styled visitor centre and the parking, the visitor facilities like a new bridge and footpath, observation hides, new signposting and information panels, the publication of tourist walking brochures and articles, maintaining the permanent exposition at the visitor centre, a layman’s report and a website for the general public. organisation of several activities in order to exchange experiences between other (Life)- projects and authorities, organisation of information meetings to inform local people
3 3. Projects
In 1989, Natuurpunt and BirdLife Belgium launched a conservation programme for Uitkerkse Polder.
In phase I, from 1989 till 1996, Natuurpunt focused on protection of last ‘high quality’ relics through land purchase and good management. A small visitor centre and two bird observation hides were build.
In 1997, the focus still on protection of relics through land purchase and good management, till the first Life-project ‘Salt meadows in the Flemish Polders’ started in 1999. This was an important step forward , were the focus shifts from ‘protection’ to ‘restoration’ of deteriorated meadows. The collaboration with farmers improves and there were an increased number of visitors (to 10.000/year).
The positive results of the first Life-project (1999 – 2002) leads to the submission of a follow- up Life-project in September 2002. This time, the large scale restoration of deteriorated salt meadows and the promotion and development of nature friendly tourism was the focus.
At the end of the second Life-project, the results can be seen on the whole project area. A significant increase of breeding birds and wintering geese were counted.
4. References
Text & maps: Leticia Gheysens, Stefan Versweyveld & John Van Gompel (Natuurpunt site manager) e-mails: [email protected], [email protected] & [email protected] Coxiestraat 11, 2800 Mechelen (tel +32.15.29 72 20)
5. Annexes
5.1. Annex 1: Map with land acquisition in the ‘Uitkerkse Polder’
5.2. Annex 2: Flyer ‘Uitkerkse polder, discover a wonderful world of birds’
5.3. Annex 3: Flyer ‘Uitkerkse polder, a surplus value for nature and people’
4 5 Annex 1: Map with land acquisition in the ‘Uitkerkse Polder’
6 7 8 9 10 11 VLAAMSE LANDMAATSCHAPPIJ UW PARTNER IN DE OPEN RUIMTE