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Revitalising Dunes in Kennemerland Dynamic nature conservation in a large urban setting

Contents Introduction Sand dunes and drinking water abstraction Amputated sand dunes Return of coastal dynamics in National Park Zuid-Kennemerland Hospitality and new recreational activities Restoration of wet dune habitat in the Kennemer dunes Volunteers at work in the dunes Effects of climate change on dune flora and fauna Marquette: a paradise for meadow birds On wisent safari in the dunes Monitoring Cultural history of Nationaal Park Zuid-Kennemerland Land redevelopment around Egmond-Binnen Seaside village vegetation: calcareous grassland of the dunes Dynamic dune management: Rejuvenation of Buizerdvlak PWN Management Memo 2015-2025 : Vital dunes, source of enjoyment Green bridges in Zuid-Kennemerland: Connecting fragmented nature

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Introduction It gives me great pleasure to introduce this brochure which relates how and why we manage a major part of the dunes of the province of North Holland. As a drinking water company, PWN also manages two nature reserves: the Noordhollands Duinreservaat (North Holland Dune Reserve, in short: NHD) and the Kennemerduinen (Kennemer Dunes), both of which are Nature 2000areas, together comprising a surface area of more than 7300 hectares. These reserves consist of dunes, both dry and wet systems and are the source of 50% of the biodiversity in the Netherlands. They are an important recreation area, and are our national shield against flooding. Much (45,000,000 m3) of the drinking water for the people of the province of North Holland is also obtained from this nature reserve. It all began at the end of the 19th century, when municipal companies began to abstract water from the dunes for supplying drinking water for their towns. The province of North Holland created PWN as a drinking water company in 1920 and in 1934 also assigned us the task of caring for the dunes used to provide the water. In the middle of the 20th century it became clear that abstraction of water from the dunes was exceeding replenishment by yearly rainfall. Salt and brackish water was being extracted from the wells. In other words, the balance was disturbed. Projects were realised to infiltrate pre-purified river water in parts of the dunes, and at the same time the abstraction of groundwater was reduced. Nowadays the areas used for infiltration of pre-purified river water take up about 5% of the NHD surface, and measures have been taken to enhance ecological qualities of these infiltration works as well. Today the intrinsic value of these natural areas is widely acknowledged. Groundwater withdrawal has been diminished drastically: today only about 10% of the annual rainfall in the dunes is used as drinking water: the rest is left to fulfil its ecological purposes. In large areas water abstraction has been stopped altogether, for instance in the Kennemer dunes. This has led to a widespread restoration of wet dune slacks. Water management hereby preserves a subterranean fresh water body that, besides its own ecological value, functions as a drinking water reservoir in case of a disaster. Fortunately, that happens very rarely, but the reservoir is an important insurance for the people in this part of the country. The cost of management of this nature reserve comes in part from parking tickets, entrance tickets and a fee for the use for the water function of the dunes. I hope the brochure gives you a good overview of the activities we carry out to preserve and increase the quality of this unique area, both for its natural values and its recreational opportunities.

PWN Water Supply Company North Holland Sjakel van Wesemael Manager Nature and Recreation


Sand dunes and drinking water abstraction The relationship between the sand dune ecosystem and drinking water abstraction has been problematic for a long time. After WWII the relationship was dominated by the negative impact on ecological values. Since the end of the 20th century there has been a change in direction. Since the sand dunes first formed freshwater has been deposit underground as a result of precipitation. In the Middle Ages the urban population began to grow. Ditches and canals became more and more polluted, and it was not long before their waters were no longer suitable for drinking water. There were incidences of diseases such as cholera and typhoid fever. Those who could afford to settled at country estates, for example at the foot of the dunes where the availability of clean water was no problem. The public importance (health and hygiene) of reliable drinking water led to the extraction of dune water for the benefit of the urban population, first at Vogelenzang in 1853 for the population of Amsterdam. Around 1900, groundwater pumping-stations were built in the dunes for towns such as Haarlem, Zaandam,


Alkmaar and Den Helder. As a result, the dune areas exploited for drinking water were protected from urbanisation. Sand dunes: a useless wilderness? Some hundred years ago the ecological value of sand dunes was scarcely recognised. The dunes were in part ‘the count’s wilderness’ and hunting grounds. Drifting sand was considered a threat. The dunes were used for various purposes, from keeping sheep to forestry. Small plots of arable land by the villages on the sea coast were cleared, and the tasty dune potatoes grew well. But plans for large-scale reclamation were made as well, and government subsidies became available. Many more ways to make the area ‘useful’ then followed: sand extraction; building and afforestation of pine during the Great Depression (1930); and

utilisation by the mining industry. The Second World War had a huge impact on the Dutch coastal dunes. The German occupation dug trenches, planted minefields and built bunkers connected by many underground tunnels. Extracting dune water is not without consequences Dune water extraction kept pace with the population growth and developments in usage, the so-called ‘water civilisation.’ In the end this led to desiccation of the dunes: more water was withdrawn than could be replenished naturally. To prevent the groundwater table from dropping further and to prevent the intrusion of salt water, plans were drafted to replenish the freshwater deposits in the dunes by means of infiltration of pre-purified river water. Halfway the 20th century, the first open infiltration areas were set up. The river water, however, had an unintended side-effect: it proved to contain many more nutrients than rainwater did. For this reason many plant species characteristic of moist dune slacks were pushed out by nettles in the infiltration areas. At the same time, however, public awareness of the value of dune habitats was rising. External pressure was exerted to break the hegemony of the water extraction companies: the Stichting Duinbehoud (Society for Dune Conservation) was established. Drinking water supply, but another way The options for extending surface infiltration were limited. Better pre-purification of

the surface water to be infiltrated became necessary. The environment had also become an important social issue by the end of the 1980s. Campaigns were launched to reduce water usage. Water-efficient shower heads and toilets were introduced. More collaboration between regional water supply companies meant more efficient use of existing resources. Jointly conducted research into possible alternatives such as deep-well infiltration and fitting surface infiltration better into the landscape led to alterations. Because of the necessity of protecting their sources, the dune water supply companies had already considered conservation an important basic principle. Water extraction and conservation Large portions of the sand dunes in North Holland are owned by the province of North Holland. In the early 20th century the province had begun to buy dune areas in order to secure them as a source of the North Holland drinking water supply. In 1920 the province established its own water supply company: Provinciaal Waterleidingbedrijf van Noord-Holland (Provincial Water Supply Company of North Holland, in short: PWN). In 1934, the province charged PWN with the management of the dune areas. The interests of conservation and water supply were regarded as equivalent. Proper management of the dunes requires research so the consequences of management measures can be predicted and monitored. The required funding is generated through the water bills, though the water customers benefit from


Proper extracting of dune water requires research and monitoring.

proper conservation as well. The dunes contain a large, well protected stock of drinking water, which is in fact a large, sheltered drinking water reservoir that can literally be tapped in the event of an emergency. Reconciliation of ecological values and water infiltration Surface infiltration strongly influences the natural groundwater system. In the Noordhollands Duinreservaat (North Holland Dune Reserve, in short NHD) infiltration takes place in two former agricultural areas near Castricum and Wijk aan Zee. The two areas together cover less than 5 percent of the total surface area of the NHD. The change brought about in the naturally fluctuating system and the different water quality caused wet dune slack plant species to disappear. Better pre-purification and concentration of infiltration and extraction in a smaller area are likely to remedy much of the damage. Surface infiltration fitted naturally into the dune landscape gives the infiltration ponds the appearance of dune lakes. To many visitors the infiltration ponds and the water birds living in them are attractive elements, ones that would really be missed. By sensible use of technical options along with conservation and restoration of ecological values, the water extraction function will continue to contribute to conservation of the sand dune habitat. More water, more plants By concentrating water extraction in a smaller area and dismantling a number of older


abstraction sites, a more natural fluctuation in the groundwater level has been achieved in a major part of the dunes. Slacks are temporarily or more or less permanently flooded now, and the water of dune streams is once again of good quality. For the most part, the restoration activities were carried out over the past two decades. On the isle of Texel, in the Grafelijkheids Dunes near Den Helder and in the Kennemer Dunes near Haarlem, PWN has halted groundwater extraction entirely. On other sites it was reduced. Existing infiltration pools were updated. They were drained dry and cleaned by removing the sludge. At the same time the banks were made more natural and sloping. The topsoil of the slacks, which became wet again, was removed on a large scale. Blowouts were again allowed to occur. This dune restoration, also known as regeneration, has been successful. Characteristic plant species such as centaury (Centaurium littorale), marsh helleborine (Epipactis palustris), southern marsh orchid (Dactylorhiza praertermissa) and early marsh orchid (Dactylorhiza incarrata) colonise the slacks again. Parnassia (Parnassia palustris) is also making a comeback. The proportion of rough herbage is declining. Natterjack toads, real pioneers, appear to have availed themselves of the new opportunities quickly. Dune water supply companies: important managers 14,000 hectares of the Dutch coastal sand dunes are managed by dune water supply companies. More than half of this area is managed by PWN.



Increase of growth places of Parnassia palustris between 1992 and 2000.

Due to drinking water extraction, road construction and building in the dunes was stopped or prohibited. The regeneration project is leading to an increase of characteristic dune vegetation and associated fauna. Besides their conservation efforts in the dunes, the water companies also create opportunities for nature-oriented recreation in the areas they manage. This results in a unique situation of well protected, but open-to-the-public natural areas close to the urban and densely populated Randstad area. Every year millions of people enjoy visiting these areas. Due in part to their geographical location the water extraction areas are important links in the western part of the Ecological Main Structure in the Netherlands. The water supply companies are well aware of their responsibilities. These include taking specific mowing or grazing measures to combat the effects of nutritious precipitation. The areas have also been designated now as Habitat Guideline Area and Natura2000-area, which adds another important responsibility to those the water companies already had with regard to the management of a major part of the Dutch sand dunes. The importance of the drinking water supply function provides a healthy basis for this management. Sjakel van Wesemael, PWN manager Nature and Recreation


Amputated sand dunes In the second half of the twentieth century, the disappearance of large insects, along with the disappearance of animals that depend on them, was noted in the sand dunes. The research project Living Dunes was carried out to find out what the causes were and to find remedies. The problem: amputation of the sand dune ecosystem Around 1930 some conspicuous breeding bird species in the sand dunes started to decrease in numbers. Some species disappeared entirely, such as the stone curlew (Burhinus oedicnemus) (late 1950s), the little owl (Athene noctua), that used to breed in rabbit holes (late 1960s), the Montagu’s harrier (Circus Pygargus) (1980s) and the red-backed shrike (Lanius collurio) (late 1980s). Other species declined dramatically, such as the nightjar (Caprimulgus europaeus), the short-eared owl (Asio flammeus) and the golden oriole (Oriolus oriolus). All these species have one thing in common: they feed on large insects and/or small vertebrates. From historical anecdotes we knew that some large, numerous insects, such as the May beetle (Melolontha melolontha) and June beetle (Amphimallon solstitialis), used to be much more abundant than at the time of the Living Dunes project. A relationship between the sad deterioration of the sand dune ecosystem and the food situation was postulated for that reason.


Research Radboud University at Nijmegen conducted research in order to discover the causes and to identify what possible measures could be taken. The problem described was recognised throughout the country, and consequently 50% of the costs were paid by the Ministry of Agriculture and Nature. The three major dune water supply companies in the Netherlands (PWN, Dunea and Waternet) were responsible for the other 50%. The field work was carried out from 2006 to 2010, and the report was finished in 2012. The aim of the research project was to find measures that could restore our sand dunes affected by acidification, over fertilisation and desiccation to their original state to the greatest extent possible. Special attention was paid to the (insect) fauna. Simultaneous studies were carried out in both the Dutch and Danish sand dunes. In the latter, acidification and overgrowth of grasses started much later. Red-backed shrikes, in Jutland for example, were still breeding in abundance. Those measures that had already had or were expected to have a positive effect on the vegetation and were expected to be advantageous to the fauna communities of the Dutch coastal sand dunes in particular were studied as well. The first two measures to be studied were creating blowout activity in some parts of the dunes and grazing of large herbivores. The focus was on management measures in the calcareous dunes beyond the coastal strip (the sea dunes of the mainland dunes). These so called Grey Dunes were stringently protected in Europe at the time and restoration of them in the coming decades was considered urgent. Results One of the most significant discoveries of the study was that during their underground larvae stage many large insects feed exclusively on the roots of vital grasses, such as marram (Ammophila arenaria). These vital grass roots appeared to occur only in dunes showing blowout activity. It appeared that the underground life of the small June beetle (Amphimallon solstitialis), was reduced by as much as one year, from three to two, if it ate vital roots instead of older, non-vital roots.

Consequently, the number of above ground beetles also increased. These slow-moving beetles are nutritious prey for insect-eating birds and other animals. This finding provided a good starting point for restoration management: create more potential for blowouts in the dunes! This argumentation, however, had one weak point: spontaneous blowouts rarely occurred anymore. Did beetle larvae also respond positively to artificially created blowouts? The research conducted gave the answer to this question: fortunately, there was no difference between the two types of blowouts.

Blowouts are starting points for dune restoration. Continuation In addition, the researchers focused particularly on the effects of grazing on the fauna in areas that had been grazed for a relatively long period of time, and the factors that were relevant to the fauna in that respect. Open, natural dune grasslands were compared to grazed grasslands and disturbed grassland strongly influenced by atmospheric deposition. Effects were studied by looking to the life cycle of grasshoppers. Development of larvae was most retarded in the disturbed grasslands. In grazed meadows the rate of development of grasshoppers was slightly improved compared to the conditions in disturbed grasslands. However, grazing cattle may have also had a negative effect on the numbers of nests of ground dwelling insects. In a later stage, other measures were to be studied such as burning, sod-cutting or perhaps small-scale farming. The project left room for studying new, promising measures as well. We hoped that in this way one day we would once again find large insects and the animals that depend on them in a natural sand dune landscape. Dick Groenendijk, PWN consultant Conservation


Return of coastal dynamics in National Park Zuid-Kennemerland For centuries, the coastal dunes of the Netherlands protects low-lying Holland from the sea. Against all tradition, five gigantic 100-150-metre wide holes have been dug to once again give the wind free rein and to allow the dunes to drift. By also setting five dune complexes further inland open to the wind, a large-scale, dynamic dune landscape has been created with characteristic habitats of white dunes, grey dunes and humid valleys.

The project Noordwest Natuurkern (Northwest Nature Core) was realised between Bloemendaal aan Zee and IJmuiden in Nationaal Park Zuid-Kennemerland (South Kennemerland National Park, in short: NPZK). The project is managed by PWN Waterleidingbedrijf NoordHolland (PWN Water Supply Company, in short PWN) in cooperation with Natuurmonumenten (Nature Monuments, in short NM)) and Hoogheemraadschap Rijnland (the Rijnland Water Authority, in short HHR) and meets the objectives of the plan for the Natura 2000 site Zuid-Kennemerland (South Kennemerland). It is financed by provincial funds and the EU LIFE+ programme as part of the LIFE project ‘Dutch Dune Revival.’ Implementation took place between the autumn of 2011 and April 2013.


Recreating dynamic dunes Project Noordwest Natuurkern targets extending the habitat of mobile white dunes by 18 hectares and the humid valleys by 7 hectares. It extends and improves the condition of grey dunes. The recovery of dynamic dunes is achieved by creating notches to funnel sand and salt spray through the foredunes and by reactivating the drifting of underlying parabolic dunes. The notches are 100 to 150 m wide at the top and are dug in a V-shape to 6 m +NAP (Dutch Ordnance Datum) rising to 9 m +NAP. The notches extend the wind and salt effect to the reactivated parabolic dunes lying directly inland. The movement of the parabolic dunes will also create embryo dune slacks. The conditions for humid valleys are also created by reusing the material of turf-stripping the mobilised dunes to shoaling a dune lake,

Cremermeer. The lake was dug sixty years ago for sand extraction and is of little conservation value. Fish (carp) were removed from the lake, the steep sides were re-profiled and shallow areas were created. The condition of the grey dunes is improved by the sand blowing over from the remobilised dunes. Existing grey dunes undergo accelerated acidification, and the richness of lime of the blowing sand stops the process of acidification. The conditions for lime-rich habitats and species improve. Why dynamic dune management and why here? Through centuries of restrictions on behalf of coastal defence and the recent nitrogenrich precipitation, the calcareous dunes were rapidly becoming overgrown and acidified. Characteristic types of grey dunes disappeared

and white dunes were lost. We started remobilisation projects inland at around the change of the millennium (Verlaten Veld 1998, Huttenvlak 1999 and Bruid van Haarlem 2002/2003). Reactivation of parabolic dunes was successful, re-establishing dynamics and mobilising sand drift, but after a number of years the sites begin to stabilise again, which indicates the projects have a limited life-span of 10 to 15 years. To prevent stabilisation in the first years after completion, follow-up management is required to remove the remains of the former landscape and vegetation. Over time, people began to think differently about the function of the foredune areas and to consider giving the wind room so that this area can act as a ‘motor’ of dynamic influences and processes for the inland dunes. With greater influence of the wind and more salt deposition,


it may be possible to create a sustainable remobilisation. Noordwest Natuurkern is the next remobilisation project of a more long lasting nature: it is being carried out near the shore on a large scale. Noordwest Natuurkern is one of the few sites on the Dutch mainland where large scale remobilisation is possible. The dune is sufficiently wide to guarantee the safety of the hinterland, and it consists of a quiet nature area with no urban infrastructure. Sustainable climate-resilient management Sand movement on a sufficient scale will ensure that the dune is rejuvenated, does not age or become acidified. The ‘sand spray’ spreads lime in varying quantities across the surrounding area, thus achieving a great variation in the amount of lime. This leads to an increase in variation in environments and species, each with its own requirements. As the parabolic dunes move, blow-outs are created on the windward side down to the groundwater. If the groundwater level rises due to climate change, the height of the dune slack grows with it and the variation is maintained. This is important, as the groundwater level is expected to change in the future due to both a rise in sea level and changes in the rainfall pattern. Using climate change predictions of a sea level rise of 35-85 cm by 2100, the slacks just behind the near shore area will become much wetter with more open water. Rainfall also is predicted to increase. According to the climate atlas for North Holland, this could potentially be 50 mm, i.e. an average rise in the water table of approximately 15 cm. With no intervention, it is anticipated that large parts of the slacks will become too wet in the future and unsuitable for humid valley vegetation.

was unlikely to have an impact on archaeologically interesting sites. The dune area of the National Park is a geological monument, and dynamic dunes are part of that character. The scale was almost too large, so special concessions were required. The sand drift locations were chosen in order not to endanger the most valuable dune slack sites and species by sand drift for the next 50 years. No plant species will be lost by the implementation of the project. To accommodate the sand drift, the recreational routes had to be changed. A beach access path had to be relocated about 400 m southward Sand movement on and will run through to the beach a sufficient scale at a much lower level, which is an will ensure that the improvement for people using it. dune is rejuvenated,

Working around constraints A number of constraints were included in the project design and implementation. The local authority had to be sure the sand drift would not cause a nuisance does not age or or weaken coastal defences. To Organising public support become acidified. allow for the project, the line of Many vested interests were present the so-called ‘primary barrier,’ the and therefore many parties were front chain of dunes for flood control involved in the planning. The project was and protection, has been moved eastward conceived in 2005 by PWN, NM and HHR and (inland). Because we anticipated growth of the dune was discussed in 2007 by the Advisory Committee and area by sand being transferred from the beach to the the NPZK Consultative Group. In 2008, discussions hinterland through the notches, the project became part were initiated with conservationists regarding the of a pilot project in the region. impact on existing species and habitats. In 2010, the The location of the excavations avoided disruption to work gained support because it would help the dunes WWI and WWII bunkers of historical interest, even adapt to climate change. In 2008, we held public though during construction some unknown bunkers were opinion surveys, from which we learned to keep the discovered. Similarly, investigations showed that the project communication small and personal during the design


phase. The plan was submitted to the LIFE+ programme in 2009, and the grant was awarded in 2010. Support was also granted from the Ministry of Economic Affairs, the province of North Holland, NPZK, HHR, Stichting Duinbehoud (the Dune Preservation Foundation) and the Velsen, Bloemendaal and Zandvoort municipalities. In 2011, we worked on the concessions and action plans needed for realisation. An extensive communication and information program was provided for the local community: newsletters, signs, websites, excursions and presentations through the visitor centre. Local, regional and national media were updated regularly. Realisation of the project After the details of the project were agreed upon and the area was checked for unexploded ordnance, the first stage began in January 2012 with the removal of vegetation from the inland parabolic dunes. The five excavations in the foredunes were completed during the winter of 2012-2013. Uses were found for the 220,000 m3 of sand from the excavation works to fill part of the Cremermeer (lake), to strengthen weak spots in the foredune, to use for the Zandpoort green bridge connecting the National Park with the Amsterdamse Waterleidingduinen (Amsterdam water supply dunes, in short: AWD) to a whole dune area of 7000 hectares and to raise the beach in Zandvoort. Results The effects of the measures are monitored in various ways. Dispersion processes are monitored by comparison

between digital terrain models, measurements at erosion markers and sand gauges. The effect of salt on the inland dunes is also monitored. To monitor the biotic processes, insects are inventoried and surveys are taken of the vegetation structure and summer birds. The first stormy season after the intervention (OctoberDecember 2013) showed that sand dispersal near the coastal strip of dunes is much greater than inland. It appears that much more sand is blowing across the dune from a dynamic coastal strip of dunes than from a non-dynamic one. This result can prove very positive for the sustainable effect of the dispersion project on the surrounding dunes. We still do not know the extent to which and how often acid grey dunes need a dusting of calcareous sand before they are rejuvenated and their quality improves. A small amount of lime may already be sufficient to sustainably return the grey dunes to a healthy state. If that is the case, the Noordwest Natuurkern project is making a major contribution to the sustainable conservation of dozens, if not hundreds of hectares of grey dunes in the Zuid-Kennemerland dunes. Nature surprises us. The notches have a tremendous effect. The blowing sand from the dispersing dunes is extensive and reaches farther than expected. The arrival of the stone curlew (Burhinus oedicnemus) was the crowning glory of our work. The public enjoys. Marieke Kuipers, PWN senior consultant Nature and Recreation Leon Terlouw, PWN consultant Conservation Ina Roels, PWN ranger


Hospitality and new recreational activities What can a dune manager do to protect nature conservation values, to minimise conflicts between recreational uses, to meet the needs of visitors and residents, and be hospitable? Dunes and local residents PWN manages some 7300 hectares of dune area between Bergen aan Zee and Zandvoort. Local residents especially use the dunes for leisure activities. Within 10 km from the dunes approximately half a million local residents account for almost five million visits of a total of six million per year. Above the Noordzeekanaal (North Sea Canal) more than half of the local residents visit the dunes at least once a month, and 30% visit once a year. So PWN has a major responsibility to meet regional recreational needs. A majority of the visitors come to experience nature, landscape and peace. And that is reflected in PWN’s policy. PWN wants to be hospitable to visitors looking for nature-orientated recreation in the dunes. Over the years 98% of the visitors have felt their visit was successful. At the same time, visitors prefer there to be more recreational opportunities AND want ‘their dunes’ to remain unchanged. When PWN


drew up their Beheernota 2004 - 2014 (Management Plan 2004 - 2014) just after the millennium, they reviewed their recreational policy thoroughly, discussing it with users and other interested parties. And successfully: the profile for recreation in the dunes is quiet, nature-oriented enjoyment and facilitates four target groups: walkers and bikers; runners and horse riders; families with children; and volunteers (for management and monitoring). To establish conservation and recreation, zoning is introduced: quiet open dune areas and more crowded zones in wooded land and near main entrances. Appropriate facilities support the zones and are tailored to the needs of the public. Zoning also minimises annoyance caused by conflicting uses. New trends, new policy The newest Beheernota (Management Plan) for 2015 to 2025 elaborates on the last period of renewing and increasing recreational opportunities and participation. The Plan also meets the main trend in recreation: diversification of demand. Increased interest in peace and relaxation, quality, adventure activities, events, use of social media and Smartphones, a healthy lifestyle and sport plays an important part in this. PWN wants to meet the needs and be hospitable to visitors for natureoriented recreation. We offer quality, variation, innovation and customised activities. To reach this aim we strive to improve the existing supply and the special experiences of nature, cultural heritage and health. We will work together with entrepreneurs in and around the dunes, to tailor to the needs of the public. To prevent and reduce annoyance caused by conflicting uses, we are very critical in regard to new recreational activities. From various surveys it appears that our visitors above all prefer to keep the dunes unchanged, although the use of the dunes for different types of leisure activities is ever increasing.

PWN wants to meet the needs of and be hospitable to visitors for nature focused recreation.

From walking to Nordic walking What kinds of activities do our visitors do in the dunes? For many decades walking and cycling have been the most popular activities, followed by running/jogging, walking the dog, going to the beach and picnicking. Bike racing used to be the next most important activity, but since the 1990s mountain biking has been growing in popularity in the Noordhollands Duinreservaat (North Holland Dune Reserve, in short: NHD). A survey held in 1994 showed that 10% of the interviewees were annoyed by racing and mountain bike traffic. From a survey in 2013 it appeared that these top two annoyances continue to exist. Just after the millennium Nordic walking was up and coming and one often encountered training groups, particularly of women over fifty, in the dunes. To present we have not been advised of any annoyance they may cause. To dune


manager PWN, however, the question arises of which future social trends will be noticeable in our dune areas and how they will relate to nature conservation purposes and the enjoyment of other visitors. Requests to the dune manager In order to get insight into our visitors’ requests for using the dune area, we have made an inventory of all the requests received. It is an impressive list. Here’s a representative selection: police dog training, archery on playing field, wedding photography reportage, filming, barbecue, dispersal of ashes of relatives, memorial signs, broadcasting experiment by radio amateurs, geocache (GPS treasure hunt), mountain bike contest, commercial ball-shooting, kite flying, having a goat graze, Cowboys & Indians party for 72 toddlers, commercial street golf, carpentry village for children as part of festival week, half marathon, Nordic walking event, covered wagon tours, bike tours, walking tours, group drop-offs, car permit for disabled persons, ice-cream cart, Canta vehicle, boosters, helicopter landing, drama events, GPS tours. In addition to these kinds of requests, we see a number of developments while on patrol, such as growing numbers of paragliders in the coastal strip, clinics on Segways and, still, many unleashed dogs. Keeping developments under control What developments have we been able to control by this policy to present? One very important issue was regulating mountain biking in the NHD. Mountain biking was increasing and led to friction between mountain bikers and walkers. Mountain bikers are not a primary target group for PWN, and new facilities for them are not planned. In consultation with the users, an arrangement was agreed upon allowing the mountain bikers to cycle on 155 km of unmetalled paths in the wooded zone until 10:30 am. The mountain bikers asked for an additional 50 km route of their own. However, only a maximum of 17 km additional route could be provided, running for just a few kilometres over hilly terrain. This was not to the mountain bikers’ liking and the arrangement of 155 km in the early morning hours was not extended further. We were also asked to lay a 5 km horse and wagon track, but a separate facility for this recreation group will not be provided. Subject to permit conditions, however, hitched up horses are allowed to use a number of metalled roads. We also hold annual talks with this group. From regular talks with horse riders we have received requests for more bridle paths. We feel there are sufficient facilities for this relatively small group. As for the issue of better maintenance of bridle paths, this we were easily able agree to.


Public surveys show that groups of runners/joggers do not cause inconvenience to our visitors. We do address groups, however, if we think they might cause less disturbance to landscape and other visitors if they would exercise in other dune zones. Checklist and permit policy As mentioned above, every year we receive many requests for use of the dune area. To ensure that requests are dealt with consistently by our staff members, we have made a checklist. The checklist formalises our policy and is simple and efficient (see box). We have the options of ‘permit activities if consistent with policy,’ ‘decline if absolutely not consistent’ and for everything in between we apply a permit policy. Sometimes we withdraw a permit if an activity is ‘getting out of hand.’. Recently, for example, we cancelled a permit because of excessive alcohol consumption during the activity.

Checklist for new recreational activities 1. Is any harm caused to nature conservation values or wildlife? (no harm to natural environment, in accord with admission rules, no damage to infrastructure or furniture, in keeping with zoning) 2. Does it cause any annoyance to other visitors? (quiet, nature conservation-oriented enjoyment, use of existing facilities, no safety risks, no increase of conflicting uses, small-scale) 3. Does it harm PWN? (compatible with image, not commercial, not setting a precedent, no risks to drinking-water supply and coastal defence) 4. Does it offer opportunities? (for image, revenue) 5.Good and timely communication

On a visitors’ evening we asked members of the public what they thought about our approach. Of course not everyone fully approved our choices, but many advocated a fairly restrictive policy. We think that with our policy, good communications with the public (visitors and those making requests), and a concrete checklist, we are prepared to deal with the future, a future in which man and nature can benefit optimally from the dune area. Marieke Kuipers, PWN senior consultant Nature and Recreation

Restoration of wet dune habitat in the Kennemer dunes

The management of the Kennemer dunes area, has shown many developments over the past decade. In many dune slacks groundwater dynamics are back and grass of parnassus has again become the rightful symbol of wet dune slacks. The past decade in broad outlines In May 2002 water collection in the Kennemer dunes, part of Nationaal Park Zuid-Kennemerland (South Kennemerland National Park, in short: NPZK), was definitively stopped. The long-running dispute over termination of drinking water collection in order to get wetter dunes was successfully resolved. Water collection had begun in 1898. It caused drying out of the dunes, as Dubois demonstrated as early as 1905. By 1991 water collection had increased to 15 million m3 a year, but after 104 years the tap was turned off at last. This milestone was preceded by twenty years of investigations, plans, discussions, even in the Council of State, and projects to avoid high water level problems on the margin of the inner dunes. The provincial Groundwater plan (1986) prescribing reduction of dune water collection finally led to full discontinuation in 2002. A far-reaching

decision like this for the sake of habitat restoration was unprecedented in, and probably outside, the Netherlands. The Masterplan But reduction and termination of water collection in itself does not automatically lead to recovery of nature. The dunes were extremely dried out – groundwater levels in almost the entire area had dropped by about 2 metres – and only one percent of the total surface area could still be defined as moist dune slack, whereas in the past that used to be one-third! The major cause of drying out was dune water collection, besides other factors such as coastal erosion, afforestation and lowering of the polder table. Stopping dune water collection would lead to a tenfold increase of wet dune slack habitat. In NPZK approximately 300 hectares were involved. Without drastic management measures, however, nature that had been lost would not be restored because the dune soil was richer than it used to be. Almost all the valleys had been used for agricultural activities such as growing dune potatoes. For that reason the so-called Masterplan was drawn up in 1999, describing systematically which management measures would be necessary for each individual valley to attain one of the desired four future habitats: pioneer


slack; dune grassland slack; blowout slack; or dune marsh slack. To provide opportunities for characteristic moist dune slack species and to combat monotonous rough vegetation, the fertile top layer of the soil in many valleys was removed or the green vegetation was mown for about ten years.

Dragonflies can survive in dune slacks and pools drying up in summer. They are doing well today. First restoration projects Earlier experience in this matter was gained in Houtglop (PWN) and Zuidervlak (Natuurmonumenten (Society for the Protection of Nature Reserves, in short: NM)) at the end of the 1980s. In 1998, the first restoration project of the Masterplan was carried out in Groot Olmen. A surface area of 7.1 hectares was mown and the humusrich top layer of the soil was removed. Due to a period of heavy rainfall the groundwater level rose more than expected. The intended blowing-out did not take place for that reason, and a large part of the valley was directly influenced by the groundwater. Since then several threatened vegetation species of nutrient-poor moist dune slack have settled: grass of parnassus (Parnassia palustris), seaside centaury (Centaurium littorale), brookweed (Samolns valerandi), little green sedge (Carex

oederi) and glaucous sedge (C. flacca). The pioneer birds par excellence, little ringed plover (Charadrius dubius) and ringed plover (C. hiaticula), found the sand flats immediately. First-year breeding pairs of little ringed plover and their young were seen. In addition, great ringed plovers engaged in courtship were spotted. Northern lapwings made breeding attempts and common shelducks frequented the pools to forage. More sod-cutting, mowing, birds… North of Groot Olmen, NM has created a blowout slack as well: Huttenvlak. This slack has a history similar to that of Groot Olmen: first a good deal of sand-blow activity, then a ‘pool phase’ and now mostly wet again. Sod-cutting in Zuidervlak and Noordervlak has also created good conditions for moist to wet dune slacks with pioneer vegetation and associated breeding birds such as little ringed plover and great ringed plover (C. hiaticula). The first moving sand dune activated by PWN was Verlaten Veld (12 hectares) at Kraansvlak, in the winter of 1998-1999. For 10 years the sand front of the dune shifted at a rate of more than 4 metres a year. Measures are not limited to sod-cutting or digging-off. At locations with lightly humus-containing soil mowing is carried out as well. At De Grote Pan rare plant species such as grass of parnassus (Parnassia palustris), red bartsia (Odontites vernus), seaside centaury (Centaurium littorale), autumn gentian (Gentianella amarelle) and alpine rush (Juncus alpine articulates), have returned, and sometimes glaucus sedge is almost dominant. Vogelmeer cluster After having levelled off the western bank of lake

Vogelmeer, ecological optimisation of the lake was completed in the winter of 2002-2003. In addition, a total surface area of 23 hectares of dune slack was sod-cut and the parabola dune the Bruid van Haarlem (Bride of Harlem) was reactivated. A large part of Vogelmeer was made shallower, particularly on the west side. The southern bank was made suitable for a larger area of reed marsh. Some small islands were created as well. Finally, the existing ‘lagoon’ on the large island was extended and a dune crest was denuded. In the adjacent, gently sloping valley of clean sand that has been created, blunt-flowered rush (Juncus subnodulosus), glaucus sedge, jointed rush (Juncus articulates), alpine rush (J. alpine articulates), little green sedge (Carex Oederi), grass of parnassus (Parnassia palustris), black bog-rush (Schoenus nigricans) and seaside centaury (Centaurium littorale) have settled. In and around Vogelmeer today we see black-necked grebe (Podiceps nigricollis), little grebe (Tachybaptus ruficollis), little ringed plover (Charadrius dubis), greylag goose (Anser anser), common shelduck (Tadorna tadorna), garganey (Anas querquedula) and northern lapwing (Vanellus vanellus) breed and raise their young. Dragonflies Due to the wetter environment and the many digging activities, availability of water has increased temporarily or permanently in many locations. Dragonflies including pioneer species such as broad-bodied chaser (Libellula depressa) and scarce blue-tailed damselfly (Ischnura elegans) clearly benefit from this situation. Species that can survive in dune slacks and pools drying up in summer, such as the rare emerald damselfly (Lestes sponsa) and yellow-winged darter (Sympetrum flaveolum), are also doing well today. And further… After a period of calm, we implemented the other half of the Masterplan. The result is over 100 hectares of wet to moist dune slack habitat with scattered small white dunes, and around 40 hectares of moving dune. Four dune lakes have been modified. Since the spring of 2004 integral grazing has been practised in most parts of the National Park. Many valleys have been mown for many years unless grazing delivered enough benefits. The results of 15 years of nature conservation measurements are overwhelming. Marieke Kuipers, PWN senior consultant Nature and Recreation Piet Veel, PWN former manager of Kennemer dunes


Volunteers at work in the dunes


PWN has been working with volunteers for nature conservation activities for more than 10 years now. Has the arrangement lived up to expectations? About 16 years ago, the Nature Conservation & Recreation department of PWN tentatively suggested having volunteers carry out part of PWN’s practical nature conservation work. Dune management activities were increasing and work was piling up. Our request for extra help dovetailed with people’s need to participate in nature conservation activities after retirement, or just to do something completely different besides a job. At about the same time PWN began recruiting volunteers for occasional Saturdays to carry out special jobs such as preserving a stretch of moorland, removing pine tree seedlings, etc. This proved successful. Today, so-called Dune Work Days are held three Saturdays a month from September to March. On these days volunteer groups varying in size from 5 up to 20 carry out activities under supervision of our green maintenance team. Local volunteer teams In 2003, the first local volunteer team was also established: a group of enthusiasts who started working in the dunes near Bloemendaal every Wednesday. Of course, it required the green maintenance team’s effort to organise and supervise, but it was very rewarding. Nowadays there are 10 regular groups of volunteers working in the dunes. Specialists The increasing use of large grazers like horses and Scottish Highland cattle and even Wisents (European bison) to control growth of grasses, shrubs and trees, made regular inspection

of fences necessary. Volunteers were asked to help with this job as well. Our volunteers also maintain and herd a flock of sheep. Some former carpenters and other craftsmen are involved in tearing down, removing and rebuilding structures. Relations management To strengthen relationships between the volunteers, PWN offers them the opportunity to issue their own newsletter. Every volunteer has been given a subscription to the magazine Between Dune and Dike, which publishes articles concerning nature conservation and nature research. In addition, every year PWN organises a special day and special evenings for volunteers to meet and exchange developments, projects and news. It is also an opportunity for PWN to show their gratitude for the volunteers’ efforts. Future There are many interesting ideas and developments to organise groups of volunteers in a different and more independent way in the near future, including in co-operation with other nature conservation organisations. Working in nature is very popular and there is a big demand for participation in the teams. Therefore the nature conservation organisations have to find a good solution for a sustainable organisation for volunteers, now and in the future.

Volunteers and PWN are happy with each other, and nature and visitors benefit from the arrangement. The fact that one sleeps well after a hard day’s work in the dunes is a welcome bonus! Marianne Snabilie, PWN manager Green maintenance team


Effects of climate change on dune flora and fauna Having the mildest winter and mildest spring (2014) since 1706 just behind us, the issue of climate change has become an everyday reality. Southern species are advancing, plants and animals appear much earlier in the year. Do we see the impact of climate change on species and processes in the PWN nature reserves in recent years?

What’s in store for us? The climate of the future will be very similar to what we have experienced in recent years: warm summers, with long dry periods interspersed with heavy downpours. Mild winters with about 10% more precipitation than in the past 30 years. An increased frequency and strength of storms might also be in store for us, but scientists are not sure about this yet, since the trend over the past 40 years has been just the opposite.

has increased substantially in recent years; aided by the implementation of nature development projects on former farmland this approach will continue in the future.

Sand blowing: uncertain If the number and strength of the storms actually does increase, it would be beneficial to the dunes. Storms carve out parts of the sea dunes, from which blowouts can develop, eventually leading to the formation of new, mobile dunes. Storms could also enlarge bare patches of sand created by rabbits and dune cattle, thereby creating What does this mean for the dunes? small blowouts. This constant renewal of the dunes is There is a constant battle in the dunes between plants and needed to counteract the effects of acidification sand. In some periods the sand wins the battle, and eutrophication (air pollution). but now the plants seem to have the upper Unleached lime-rich sand is brought to hand. Climate change has brought about the surface and scattered by the wind an obvious extension of the growing on the surrounding ground. Plants season. Plants now have a much and animals of young dynamic longer time to store reserve food for Greening of the dunes, which are amongst the most the winter in their roots, etc. And dunes causes trouble threatened species, will benefit. the sand has less time to defeat the for the real ‘dune plants. The result is a clear greening desertlovers’. Breeding birds take of the dunes, which causes trouble advantage of mild winters for the real ‘dune desert-lovers,’ The changes in the presence of breeding especially the drought and heat loving birds due to climate change are not as plants and animals. How this develops striking as in many other species groups. in future will depend mainly on the predicted summer droughts. If indeed they become longer and more But the low frequency of severe winters since 1997 leaves traces in the form of a growing trend among species frequent, the balance may again tip in favour of the sand. susceptible to harsh winter conditions such as bittern (Botaurus stellaris) and kingfisher (Alcedo atthis). Wet dune valleys: no longer a source of Both species have been increasing nationally since 1997. concern The wet dune valleys have seen improvement not only due The bittern settled as a breeding bird in the PWN dunes in 2001, the kingfisher in 2002, and since then one pair to the increased rainfall, but also from the reduction of (for bittern sometimes two) of each species breeds there water extraction and a variety of local measures. The area


About 700 permanent ‘sniffer trees’ noted as early as 2002 that southern species are advancing and northern species are becoming rarer.

annually. The decline of the whinchat (Saxicola rubetra) is also possibly due to climate change. This species, which is no longer a breeding bird in the PWN dunes, has withdrawn to the cooler northern and mountainous areas of Europe. Insects migrate north A warmer climate is not necessarily beneficial to insects. Due to the rapid growth of vegetation, the (micro) climate close to and in the soil where the larvae of insects are often found, may actually become cooler. Due to the longer growing season, species may be able to start a new generation, but may not have enough time to go into winter dormancy at the right stage. Drought might reduce the nectar supply. On the other hand, in a mild winter insect growth can start sooner and continue longer, as is evidenced by the red-veined darters (Empetrum fonscolombii) that occasionally emerge in the PWN dunes in spring. Until 1991, the wasp spider or tiger spider (Argiope bruennichi) was found only in the south of the province of Limburg. Since then it has steadily expanded to the north. In 2002, it was recorded for the first time in the Kennemer dunes. In 2005, the species reached the Noordhollands Duinreservaat (North Holland Dune Reserve, in short: NHD), where it was seen in five places. In 2006, concentrations of up to 25 females with egg cocoons were seen near the Papenberg (in NHD). Nowadays, the species can be found as far north as Bergen. The croaking calls of grasshoppers and crickets are inextricably linked with dry, sunny weather. Due to higher spring temperatures, many species are seen or


heard earlier nowadays than before. Several species are involved in a march to the north such as the lesser marsh grasshopper (Chorthippus albomarginatus), now widespread in the dunes. The sickle-bearing bush cricket (Phaneroptera falcate) is an interesting newcomer. This species established itself (after an incidental observation) in 1980 in the Netherlands (Brabant, Limburg). In 2003, a population was established in the Kraansvlak. The species has recently expanded to the NHD as far as Bergen. Due to their good flying ability and their wandering tendencies, dragonflies can quickly respond to climate change. The small red-eyed damselfly (Erythromma viridulum) is a southern species that has become increasingly frequent in the Netherlands since the 1990s, and has also colonised the PWN dunes. Here the species is found by various waters created by the restoration of dune valleys. The same applies to the emperor dragonfly (Anax imperator), now a common species in the PWN dunes. Another travelloving dragonfly from the south is the red-veined darter (Sympetrum fonscolombii), spotted annually since 1998, and also observed reproducing in bare, shallow dune pools. Lichens respond rapidly Because of their diaspores as fine as dust, lichens respond rapidly to changes in their environment. With the epiphytes monitoring network in the NHD (about 700 permanent ‘sniffer trees’), it was noted as early as 2002 that southern species are advancing and northern species are becoming scarcer (see table). In total, 30 southern species appeared or increased in the monitoring network in the period from 1990 to 2000, and not a single northern species. Twelve northern and two southern species have decreased or disappeared.

Table. Change in species composition in relation to the geographical distribution of the species (source: Sparrius and Aptroot 2001), taken from the epiphytes monitoring locations in 1990, 1993 and 2000

changes 1990-2000 newly found increase of more than 100% 1-100% increased decreased disappeared




14 3 9 9 7 8 0 6 2 5

0 0 0 5 7

Dutch flora grows Although plants do not generally colonise as fast as lichens, we also see remarkable changes in this group. Nationally, climate change is now an even more important cause of increase or decrease than desiccation or eutrophication, and due to this the number of species in the Netherlands is growing. In the dunes we see these changes in the sharp expansion or establishment of species such as narrow-leaved ragwort (Senecio inaequidens), early sand-grass (Mibora minima), maiden pink (Dianthus deltoids) and rock samphire (Crithmum maritimum). Orchids with their fine seeds can respond relatively rapidly. The lizard orchid (Himantoglossum hircinicum) has established over the past 5 years at various places in the Kennemer dunes, and has now also reached the NHD. The bee orchid (Orchis apifera), like lizard orchid a frost-sensitive species hibernating as rosettes, is also expanding to the north and reached the NHD in 2007. But the most striking is the early flowering of many species, and also the remarkable second flowering period of many species, including the exuberant flowering of spindle (Euonymus europaeus), glaucous sedge (Carex flacca), Nottingham catchfly (Silene nutans) and parsnip (Pastinaca sativa) in late autumn in recent years. Hubert Kivit, PWN head Research Dick Groenendijk, PWN consultant Conservation Rienk Slings, PWN former ecologist


Marquette: a paradise for meadow birds Not only does the Marquette estate with its castle offer a slice of cultural history, it has a combination of a unique meadow bird reserve with water storage as well.


Marquette estate The Marquette estate (110 hectare) consists of gardens, lanes, wooded parcels and wet meadows. It is located at the boundary between dune and polder in Heemskerk. The reserve is owned in part by the province of North Holland and the rest is the property of the Landschap Noord-Holland Foundation. PWN is responsible for nature management of the reserve. Meadow bird reserve de Kampen (20 hectares) lies on the east side. In 2010, this reserve was expanded by adding 5 hectares of meadowland and 10 hectares of water storage. Hoogheemraadschap Hollands Noorderkwartier (regional water authority Hollands Noorderkwartier, in short: HHNK) , in consultation with PWN, was responsible for the latter. Excess water can be collected in case of surplus rainfall. Clever arrangement of the reserve also provided opportunities for nature, and especially for meadow birds to feed and breed there successfully. Valuable On a national level, meadow birds are not doing well in the Netherlands, except for in a few areas. Project Marquette provided some welcome opportunities, but we still had to wait to see what course nature would take. Thanks to the special layout and intensive management we now know that it is possible to develop very healthy meadow birdlife at an ‘improbable place,’ that is to say near an old, tall forest with many birds of prey, crows and foxes and close to a residential neighbourhood. A veritable colony of lapwings (Vanellus vanellus), godwits (Limosa) and redshanks (Tringa tetanus) has sprung up, and the most threatened species, for example the ruff (Philomachus pugnax), are now also regularly spotted. Marquette also distinguishes itself in a positive way in comparison with other meadow bird reserves in much more favourable locations. The number of birds migrating to Marquette from the surrounding meadows is increasing all the time. Protecting meadow birds During breeding season, plastic electric fence is erected along the banks of ditches in the meadows to keep out the foxes (and the dogs from the adjacent residential neighbourhood). Meadow birds breeding here are lapwings, godwits and redshanks, oystercatchers

Clever arrangement provides opportunities for nature, water storage and meadow birds.


(Haematopus ostralegus) and snipes (Gallinago gallinago) . But wild ducks (Anas platyrhynchos), avocets (Recurvirostra avosetta), gadwalls (Anas strepera), garganeys (Anas querquedula), shelducks (Tadorna tadorna), shovelers (Anas clypeata), mute swans (Cygnus olor), coots (Fulica atra) and tufted ducks (Aythya fuligula) have also been spotted. Song birds such as meadow pipits (Anthus pratensis), skylarks (Alauda arvensis), blueheaded (Motacilla flava) and white wagtails (Motacilla alba) know where to find the reserve to breed. Once in a while the corncrake (Crex crex) and spotted crake (Porzana porzana) are seen as well. Collaboration leads to success We can sustain this success and expand it as well by collaborating with various parties. Local farmer Jaap


de Ruijter is collaborating by supplying young livestock for grazing, which provides dynamic and open spots during the breeding season. He also cuts hay from the land so there will be other open places for the meadow birds the following year. Together with the local wildlife management unit, we make sure the number of foxes are kept low in the area surrounding the estate in order to ensure that the fox fence works satisfactorily. Botanical management Meadow bird grasslands are richer in flowers and thus also in butterflies and other insects than regular meadows. Flowers at Marquette include many greater yellow rattles (Rinanthus augustifolius), sorrels (Rumac acetosa) and the pink ragged robin (Lychnis flos-cuculi). Rietorchids (Dactylorhiza praetermissa) also grows here. Early in

the year the large light-yellow spots of marsh marigolds (Caltha palustris) announce the coming of spring. Besides butterflies like small whites (Pieris apae), the common blue (Polyommatus Icarus), meadow brown (Maniola jurtina) and six-spot burnet (Zygaena filipendula) are also spotted frequently here. Further towards the castle lie grounds managed especially for the plants. Very unusual plants like briza, blysmus, carex, bulbous foxtail (Alopecurus bulbosus) and sea arrowgrass (Triglochin maritima) grow here.

death, Ger continued the work. He controlled the water level, consulted with the farmers, placed nest protectors, maintained the fox fence. The meadow birds benefited from this. Ger died unexpectedly in 2008. His brother Robert and Ger’s son Ruben tirelessly carry on the bird work. Paul van der Linden, PWN ranger Jenny van Rijn, PWN senior consultant Communications

Stoker family The meadow birds at Marquette owe a great deal to the Stoker family. Wietse Stoker started keeping track of bird life in 1987 along with his son Ger, who later became a forester at manager PWN. After his father’s


On wisent safari in the dunes A herd of wisents lives wild in the Kraansvlak dune in a daring project to study whether these animals can help keep the dunes open and to see if the wisents and the public can co-exist.


On April 24, 2007, after a long journey from Poland, three wisents were introduced to a Dutch landscape for the first time in their lives: the Kraansvlak, part of Nationaal Park Zuid-Kennemerland (South Kennemerland National Park, in short: NPZK). They walked quietly out of their boxes and immediately climbed to the top of the first dune they saw. The contours of the impressive animals were silhouetted against the morning sky: it was a wonderful moment for the team involved when they saw the wisents in the dunes! Smart animals, since from that summit they had a clear overview of the area. They quickly disappeared into the cover of shrubbery and forest from where they only could be monitored via the GPS transmitters on their collars. On March 18, 2008, these three wisents, a young adult bull and two cows, were joined by three more from Poland, two adult cows, one of which was accompanied by her calf born in the spring of 2007. Within half an hour after their release, the two groups found one another and merged into one group. With the second release, the pioneer group of the first Dutch wisent project was complete. The group was allowed to engage freely in activities these wild animals always do: graze, forage on shrubs, strip bark from trees, wander around, take sand baths and reproduce. The wisent bull did a great job at the latter and is now the father of 17 calves (March 2014). Researchers from various Dutch and international universities closely monitor the herd, their behaviour and the effects of their presence. This is one of the main objectives of the project: record experiences while these wild and still vulnerable (IUCN Red List) species live under the most natural conditions in the Dutch context, and share this knowledge. Project phase The animals live in the approximately 300 hectare dune area Kraansvlak, an area fenced off to the public. The initiative for this pilot project was taken by a project group consisting people from PWN, ARK Nature, Kritisch Bosbeheer (Critical Forest Management) and Stichting Duinbehoud (the Dune Preservation foundation). The project was initially set for 5 years (from 2007 to 2012). Due to its success and the eagerness of the researchers to acquire more detailed knowledge, PWN and ARK prolonged the project by 5 years (from 2012 to 2017). Not only the ecological elements are of interested, but so are the management aspects and the public interest and response. The knowledge gained is ultimately of great interest for further reintroductions to other Dutch and European nature reserves. Kraansvlak area Before the project began we knew very little of the wisent, and what we did know came mainly from studies carried out in Poland. There the animals are often given supplementary feed in wintertime, but in the Kraansvlak we felt the animals should be able to take care of their own food supply, including during the winter months. Wisents were regarded as forest animals, as might be deduced from their narrow build. They are known for their ability to strip bark from trees and shrubs, and they do not hesitate to push over trees for that purpose. Such behaviour is seen much less in cattle and horses, and in that respect wisents play a unique role in ecosystem dynamics. Wisents also love taking sand baths. Areas like the dunes, which are dynamic by nature, had much to gain from these wild giants, some of which weigh as much as 900 kg.


Ecological studies Researchers are studying the wisents’ foraging behaviour and the impact of the animals’ food choice on the development of the vegetation in the area. This is done by monitoring their food choice and feeding activity, and by periodically taking measurements along vegetation transects. Some of the animals have GPS collars which transmit their position several times a day and also record the level of activity. The positions are plotted on a detailed vegetation map, so we know quite accurately how the animals exploit the different habitat types. The same kind of research is being done with the Konik horses that have also lived in the area from 2009, and with the Scottish highland cattle living in the adjacent Kennemer dunes. In 2012, at the end of the first five year pilot we concluded: • based on their appearance, their behaviour and reproduction, the animals are doing well in the dune area; • contrary to the common opinion regarding their preferred habitat, the wisents do not restrict themselves to the wooded parts of the terrain, but prefer rough grasslands and shrubs for foraging and use sandy patches for resting and ruminating; • although in general the diet composition of wisent and cattle appear quite similar, looking into it in more detail shows that there are distinct differences between the animal species: they forage on specific woody species in different seasons, and also prefer different parts of woody plants. Wisents appear to eat far more bark, and cattle consume twigs to a larger extent; • wisents seem to feed more as an intermediate type compared to the grass/roughage eating cattle. This is indicated by the activity level of the wisent, which includes more peaks during the day. Apart from the data, some clear field changes are also visible: the Euonymus shrub is quickly deteriorating as a result of bark stripping by wisents, and there are more sandy patches due to their sand bathing behaviour.

Public interest Seeing how the wisents are using the terrain is very special and exciting. Once you see an impressive animal such as a wild wisent, you never forget it. Visitors not only from the neighbouring area but also from the rest of the Netherlands and surrounding countries are coming to the Kraansvlak and showing interest in the project. A special lookout point was made for the public on the Kraansvlak lakeside. On warm summer days there is a good chance of seeing the animals nearby or even standing up to their bellies in the water. You can also go on a safari to look for the wisents in the Kraansvlak with a forester guide. These excursions are always fully booked in advance. After five years of positive experiences, a special walking path was opened in the western part of the Kraansvlak. Outside the bird breeding season visitors are more than welcome to make use of this path on their own and to have the chance to see a wisent in the wild. We advice: Whenever you see a wild animal like a wisent, show respect and keep your distance (in the Kraansvlak: at least 50 meters). It will increase your chance of a great sighting of this magnificent animal species: a unique opportunity in Europe! It is even more exciting as, after a selection procedure by Belgian TV channel Een, the wisent was selected as one of the Big Five in Europe. For the trail and more information on the first Dutch wisent project: Yvonne Kemp, ARK Nature and PWN ecologist Jenny van Rijn, PWN senior consultant Communications

Monitoring Managing nature is a long-term process. However, researchers who work with an organisation for more than 30 years are becoming rare, which is why PWN invests in annual collection of information about the dunes for decades. Research data over extended periods allow us to spot trends and intervene effectively.

Research The dunes managed by PWN fall under the aegis of Natura2000. We are increasing our knowledge of these reserves via research, which we differentiate into three types: evaluation; detection; and accumulation of new knowledge. The emphasis at PWN is on the first two. In evaluation research we check what the effect of our management is so we can learn from it and make corrections. Detection research is of a whole different order: we constantly keep our finger on the pulse and try to observe trends. Continuous monitoring to answer our questions which encompass the quality of the livestock, how the summer bird situation is developing, or the quality of our reserves in general. For example, we have a data collection programme which entails meticulous recording of the vegetation found in 500 random spots every year. This type of long-term research is very important because human memory is sometimes very selective. Long-term successive samples help us to objectively deduce patterns. Thus we increase our knowledge and develop our understanding of what is happening in the dune ecosystem. The third variant, research to gain new information, is always aimed at a very specific question. For example, why is the wheatear declining? Volunteers welcome Not only do we use our own rangers and call in specialist agencies for our research, we also get help from large numbers of enthusiastic volunteers. For example there is a group which annually combs through a different area of a square kilometre to identify all plants growing in it.

There are also volunteers who help us with their knowledge of summer birds, lizards, mushrooms, dragonflies, fish or butterflies. We share all research data with national data collecting networks. These networks in turn also provide us with very useful reference material. Nevertheless, it is not necessary for a volunteer to contribute knowledge per se. Many people faithfully help us by emptying and repairing sand traps every week. Sand traps are placed randomly on the top of dunes to catch drifting sand. From this we deduce where the sand originates and how it affects the dune ecosystem, as dune sand rejuvenates and brings in a new supply of lime and nutrients. International exchange Thanks to the large amount of research, we are also in contact with researchers internationally, an important network because of course our nature does not end at the national borders. Take the research by Bert Buijzer for example, who has ties to the Vrije University (Amsterdam). He researches the consequences of climate change on crowberry and studies this species from Bergen (Netherlands) to Spitsbergen, which are the southern and northern boundaries of its habitat, respectively. Along with the two other dune water supply companies in our country, Dunea and Waternet, we are in search of reference material abroad on the increasing nitrogen precipitation in the dunes. We found a reference area in Wales, for example, where they are not troubled by nitrogen precipitation as yet. Incidentally, we are also collaborating on this with the KWR national research institute. Hubert Kivit, PWN head Research


Cultural history of Nationaal Park Zuid-Kennemerland

This article is not a lyrical narrative of the outcome of archaeological or historical investigations in the Nationaal Park Zuid-Kennemerland, but instead concerns the approach to how to get an understanding of the cultural history of the park. From inventory to task force The project was initiated by the chairman of Nationaal Park Zuid-Kennemerland (South Kennemerland National Park, in short NPZK) in 2004. First an inventory was made of the cultural-historical values of the park in cooperation with expert volunteers. We now need to draw up a policy with the responsible organisation as well. The initial inventory of the cultural history of NPZK was carried out by the Centre for Cultural Heritage of North Holland based on written sources and was completed in 2005. It was an excellent starting point for NPZK to accomplish with the assistance of twenty expert volunteers from the region. A task force, Cultural History NPZK, was made up of staff from managing organisations and committee members from two local historical societies. In 2006, the task force arranged six theme sessions and two final meetings. The task force first endeavoured to complete the history of the park and the surrounding area.


The history of the area can be roughly divided into four main periods of time: 1. Early historystory In prehistoric times people lived on beach embankments and old dunes, the only parts of western Holland fit for habitation. Human habitation dates back as far as the year 3000 BC. Recently, traces of habitation were also revealed and excavated in the dune area, leading to the unique find of three settlements dating back to the 5th and 6th century: the Early Middle Ages. The inhabitants were agricultural and cattle farmers. They used pottery from the German Rhineland region. 2. Formation of Young Dunes Formation of young dunes began in the 8th and 9th centuries. Around 1200 AD blowout activity was apparently so fierce that the dunes became nearly uninhabitable. Land reclamation allowed people to move inland, while the dunes continued to be used as hunting grounds. The population of rabbits was maintained by dune bailiffs for that reason. The Brederode family ruled the dunes for 400 years. 3. Late Middle Ages In the 16th century, the availability of clean dune water gave rise to industrial development. Many dune streams had been turned into narrow, dug dune channels during the Middle Ages. The water then provided opportunities to operate paper mills, laundries and breweries. The first manors were built, and following the introduction of the track boat a century later, the first country estates were created. Sand from Elswout was used to construct the canal-side houses in Amsterdam. The character of the dune margin became entirely different from that of the dunes, ‘the wilderness.’ 4. Land reclamation In the French era, around 1800, a period of extensive human intervention in the dunes set in. The dunes near IJmuiden were partially levelled, and the sand was used as foundation under Amsterdam Central Railway Station. From 1850 potato growing expanded rapidly in the dunes in response to the potato blight elsewhere. The coastal strip was fixed. In 1898, the town of Haarlem began extracting dune water. From 1920 on there was large-scale afforestation. During the Second World War large parts of the dunes were turned upside down due to construction of the German Atlantic Wall. The last two centuries have had a decisive impact on the current dune landscape, which is clearly visible in many locations.

The wind brings the past to the surface.

Conserving and experiencing ancient treasures The history of the area was reported in consultation with the expert volunteers and task force members. We were unable to draw up a policy with the volunteers. In the coming years we will begin a new project with responsible organisations and interest groups and individuals to draw up a policy on cultural history. What is to be preserved and what can visitors experience. How shall we manage the ancient treasures? Marieke Kuipers, PWN senior consultant Nature and Recreation, and former chairperson of the task force Cultural History of NPZK


Land redevelopment around Egmond-Binnen PWN has transformed agricultural land into a nature conservation area at 15 locations around Egmond-Binnen. The landscape around the village of Egmond-Binnen is known for its geological values, archaeological sites and cultural-historical elements. Take an old map from 1821, cover it with a contemporary one and look at it: almost all the old roads, trails and waterways are still there, some in good and some in poor condition. Together they form a small-scale landscape that is worthwhile restoring. In principle, the inner margin of the sand dunes has great nature-conservation value potential. Due to the differences in height between dunes and adjacent polders and the higher groundwater level in the dunes, calcareous clean dune water flows to the lower parts. That is a rare situation in the western part of the Netherlands, one which offers wonderful opportunities for the formation of dune streams and the associated flora and fauna. The agricultural plots in Egmond-Binnen became available for nature restoration when the plots were voluntarily sold or their tenancies terminated. They border on the Noordhollands Duinreservaat (North Holland Dune Reserve, in short: NHD), managed by PWN on behalf of the owner, the province of North Holland. PWN was therefore asked to carry out the desired nature restoration project in collaboration with the municipality and the province.


Cultural-historical impact statement But before starting any digging activities, PWN wanted to get a clear picture of the past. ARDA Consultancy for nature, cultural history and recreation was therefore commissioned to carry out a Cultural-Historical Impact Statement (CHIS), a picture ‘through the ages’ of this slice of dune land. The study also included the cultural history and nature-conservation value potential so PWN would be able to make well-balanced decisions regarding the nature restoration to be carried out. Eventually it all came together in a plan in which 15 sites were designated for nature recovery. In consultation with the directly concerned government agencies, stakeholders and the inhabitants of Egmond-Binnen the plan was definitively shaped. Thanks to subsidies from the government and the province the work could then be started. Digging After the required permits were obtained, one of the first sub-projects was moving a parking lot from the dunes to the west. Hidden behind an artificial dune, visitors now park their cars out of sight. The old parking lot was transformed into a place where young and old can experience nature very directly. There are two shallow pools, inviting people to explore and play. The grounds that belonged to farmhouse Waterrijk were also radically changed. The six hectare area had been used as fertilised pastureland. The humus layer was excavated down to the bare, poor sand. As a result, the ground surface came closer to the groundwater. For that reason

a shallow pond was also dug, thereby creating an ideal starting point for plants and animals that love moist, poor inner-dune-grasslands such as the reed orchid (Dactylorhiza majalis subsp. Praetermissa), marsh helleborine (Epipactis palustris), marsh bedstraw (Galium palustre), fairy flax (Linium catharticum), their natural insect species and of course salamanders, frogs and (natterjack) toads. Elsewhere, dune streams and ancient dune plots were restored. These small fields can already be seen on old maps from the 19th century. The fields were used by local people for growing crops like potatoes and rye. In the mid 20th century, the fields were abandoned but the old earth-wall structures were still clearly present in the landscape. In a number of fields arable weeds now grow, or sometimes still rye. This attracts many birds such as the partridge (Perdix perdix), especially in the winter. A former flower bulb field was also returned to nature after removing a three (!) kilometre drainage pipe from the 2.5 hectare area and excavation of the fertilised top layer down to the clean dune sand. A stream bed was created in which two dune streams come together. Bleaching field During the inventory by ARDA the dunes revealed a secret. A still completely intact bleaching field from the early 17th century was recognised in the landscape. As far as we know, it is the most northerly bleaching field in the dune margin. The bleaching of linen was a time-consuming process and required a great deal of clean water. For that reason, a few centuries ago many bleaching fields could be found along the entire dune strip in the Netherlands. Today these are all gone, so this discovery was a revelation. PWN incorporated the recovery of the bleaching field in its plans and called in archaeologist Wim Bosman for further investigation. He meticulously documented every trace on the surface and in the soil and gave his advice. The bleaching field was reinstated in May 2010. Re-use of soil Most of the soil released during the project could be re-used in the immediate vicinity. For example, the excavated soil from Waterrijk was re-used in laying out a new flower bulb field elsewhere. Much of the soil could be used for roadwork at Schoorldam. Nature experience New paths were made for visitors so the new nature conservation area can be experienced up close. There are information boards along the route that explain the ancient history and the new nature developments to be expected. Researchers are following developments with eager anticipation. In 2014 another 2.5 hectares were added: a developer had to make compensation for sand lizards (Lacerta agilis)because of developments elsewhere near the coast. So the former bulb fields were landscaped into a lizard habitat with sand from a renaturing project. Hopefully, another few plots will be transformed and added to the dune reserve in the years to come.

Dune streams were recovered, pastureland transformed into new nature, flower bulb areas turned into a nature conservation area and a parking lot was converted into wet dune nature by relocating it outside the dunes.

Leon Terlouw, PWN consultant Conservation Jenny van Rijn, PWN senior consultant Communications


Seaside village vegetation:

calcareous grassland of the dunes Seaside village landscape in the North Holland Dune Reserve is primarily concentrated round Wijk aan Zee and Egmond aan Zee. It was created through centuries of intensive use by these villages and has an unusually high ecological value. Unusual ecological value

Plant species that are rare in our country have a special bond with the seaside village landscape, for example yarrow broomrape (Orobanche purpurea) and oxtongue broomrape (Orobanche picridis), Spanish catchfly (Silene otitis) and Nottingham catchfly (S. nutans), kidney vetch (Anthyllis vulneraria) and the well-known pyramidal orchid (Anacamptis pyramidalis). Special plants often also attract special insect species. Caterpillars of the white spot (Hadena albimacula) depend on Nottingham catchfly. Nowadays this uncommon moth is mostly found in the vicinity of IJmuiden and Egmond. The viper’s bugloss (Hadena irregularis), the caterpillars of which live on Spanish catchfly, is even rarer. This moth has only been found in the dunes round Egmond, but there is some question of whether the species is still present there as it has not been recorded for years. Calcareous grasslands

The flowery grasslands round the seaside villages share a number of qualities with the calcareous grasslands of Western Europe. You can characterise them as the calcareous grasslands of the dunes. The similarities in the abundance of flowers and biodiversity


originate in soil structure and management history. The soil structure is distinguished by high availability of lime along with high availability of phosphate and rapid conversion of organic material. This results in an open soil rich in humus in which plants can germinate easily and in which calcareous fragments are constantly present. These soil characteristics closely correspond with the intensive historic use of the grasslands. Management

Two factors are important in the management. First, maintaining the intensive effect caused by humans the way it used to be done by the seaside villages. Such use can be characterised by periods of intensive grazing, removing firewood and sod, and agriculture involving the use of fertilisation with fish-offal, for example. There was even overexploitation during some periods, followed by temporarily leaving a completely exhausted landscape to its own devices in order to recover. Second, grazing. Grazing cattle trample existing humus packets and mix lime and humus. In the management practice, a seaside village grazing regime is interspersed with aspects of the first factor. Old fields were left fallow. The age-old custom of cutting the common sea-buckthorn (Hippophae rhamnoides) and other brush for firewood, cutting sod and removing humus is imitated by removing wood, moving and cutting sod in places. Some of these seaside village sites may also be foraged and dogs are allowed to run free. Dick Groenendijk, PWN consultant Conservation

The flowery grasslands around the seaside villages share a number of qualities with the calcareous grasslands of Western Europe, including the presence of the well-known pyramidal orchid (Anacamptis pyramidalis).


Dynamic dune management:

Rejuvenation of Buizerdvlak Dynamics are an essential process for keeping dunes healthy.

In 2010, in the dune area by Bergen and on the border of the Noordhollands Duinreservaat (North Holland Dune Reserve, in short NHD) and Staatsbosbeheer (Dutch Forestry Commission, in short SBB) a stabilised dune of 5 hectares was reactivated. We began by clearing out the grasses, bracken and scrubs. Because this dune, Buizerdvlak, is located in a restricted area we also removed 2 hectares of pine forest (that was already nearing the end of its life) in the direct vicinity so the public could see the development of this dune from a foot path/cycling path. In days gone by people saw blowing sand as a threat: the Dutch dunes are a defence against the sea. Therefore afforestation took place on a large scale in the 20th century to keep it from blowing away. But in the end, no dynamics can kill the dunes. Over the last decades PWN introduced several projects as an experiment to learn the art of reactivating the old dynamic process. Geomorphologist Bas Arens advises PWN in this process and is also involved in monitoring developments. He mentioned Buizerdvlak as a potentially

promising project: it is only about 400 meters from the sea and the sea-dunes are relatively low, so there is a great deal of wind power and salt spray to get the process going. This was the first remobilisation experiment for PWN on a landscape scale in a dune area with sand with low lime content. Given free range, the wind did what we expected. Sand blew away: Buizerdvlak started ‘to walk’ eastwards. It does not move as an entire dune: some parts go faster than others. In three years the maximum deflation has been 4 meters, the maximum deposition 3.5 meters. Old roots and young seedlings of marram grass (Ammophila arenatia) are removed manually on a regular basis to keep the process going. The sand that became available by rejuvenation (approximately 40,000 m3) was used for the creation of low artificial dunes in an area of former agricultural fields and for renovation of waterworks in the dunes. The project was realised by co-financing from Government subsidies.

Before and after the clearing.


Leon Terlouw, PWN consultant Conservation Egbert van Diepen, PWN ranger

PWN Management Memo 2015-2025

Vital dunes, source of enjoyment PWN manages 7,290 hectares of dune reserves. Once every ten years we set down our policy for management thereof in a Beheernota (Management Memo) for the owner of this dune reserve: the province of North Holland. Task PWN manages a large section of the North Holland dunes under the authority of the province of North Holland. The area managed by PWN is 7,290 hectares; it serves important functions and is of great value to society. As the land owner, the province has signed an agreement with PWN to cover three social tasks: provide safe, reliable drinking water; manage the related nature area; and ensure suitable recreational opportunities. The PWN Beheernota 2015 – 2025 is our vision of and policy choices for nature conservation and recreational management for a new ten-year period. Retrospective and together into the future The Beheernota was created in close collaboration with those around us. Thanks to consultation rounds with town hall meetings and a managerial conference, we now have a Beheernota in which all of society, across the board, is heard. In the Beheernota PWN reviews the previous management period and concludes that: the dunes encompass more than 50% of Dutch biodiversity; that natural processes are recovering; that we are involving more people in our management; and that visitors are enjoying it all to their heart’s content. We use these results here as our starting point: we note that some measures have inadequate effects and that future developments could be either threats or opportunities. We will revise our management in the coming years as necessary. New vision Our new vision through 2025 consists of six core themes under the motto “Vital dunes, source of enjoyment.” We are going to work on vital, ecologically resilient dunes to make them more defensible against the increasing pressure of climate change, nitrogen precipitation and advancing exotic species. We are going to incorporate water extraction and recreation in the dunes even more sustainably in order to preserve nature, scenery and cultural heritage for the long term, too. From studies we know that THE source of enjoyment stems from the qualities of the dunes: nature, scenery and peace and quiet. We facilitate quiet, nature-oriented recreation in order to allow as many people as possible to enjoy the dunes AND to realise nature objectives. 98% of the

visitors now find their visits successful. However, we expect the demand to become more and more diverse over time, which is why we are putting more effort into hospitality, quality, variety and renewal. We strive to facilitate more involvement of visitors, residents and water customers in nature conservation and sustainability. We stimulate involvement via communication and participation. The more people deepen their relationship to nature, the broader the support for nature conservation. The willingness to contribute increases with this, making our management sustainable. We also want to broaden the front of collaboration with the region, in as many dimensions as possible. Good for support, good for the region. After all it is good if everyone can contribute to sustainable dune management, and that does not always have to be financial, quite the contrary. Contributions in kind, such as assisting with management, are also very welcome. What’s next We will be working on the above-mentioned six core themes in the next ten years, elaborated into policy in the management memo. Policy for our reserve in Noord-Kennemerland (North Kennemerland) will be elaborated in regional plans later. We have drawn up a joint ten year plan together with co-managers and the relevant government agencies for the Nationaal Park ZuidKennemerland (South Kennemerland National Park). Most of the nature management will be elaborated and guided by Natura 2000 management plans. All plans will go into effect in the middle of 2015. Marieke Kuipers, PWN senior consultant Nature and Recreation


Green bridges in Zuid-Kennemerland:

Connecting fragmented nature


The dunes in Zuid-Kennmerland are a major hot spot for biodiversity. Note, however, that natural migration in this area is severely handicapped by habitat fragmentation. In December 2013 the first green bridge in the area, connecting the Amsterdamse Waterleidingduinen with the Kraansvlak, was finished. Two other green bridges will be built in the near future. Threats A railway and two big motorways are responsible for the fragmentation of valuable dune habitat in Zuid-Kennemerland (South Kennemerland). For many animals such as insects these roads are an insurmountable obstacle. Many small and large animals end their lives as road kill. The genetic variation of these species is under pressure, and there is a major risk of local die out, which could lead to

Blue-winged grasshopper will find new home, thanks to green bridges.

less biodiversity. Furthermore, spreading of ecosystem engineers like rabbits (Oryctolagus cuniculus) is also seriously hampered by the fragmentation effects of the motorways and rail-way. Local extinction and reduced spreading options for the rabbits may also have an effect on the various dune habitats. To counter these negative effects, plans for three green bridges in the region were made, the first of which was finished in late 2013. Results Building the three green bridges will improve migration opportunities for many species, including rare ones and essential ecosystem engineers like rabbits. The green bridges will reduce the quantity of road kill, and because the green bridges will be designed out of natural dune habitat, the green bridges themselves can be inhabited by insects and slow moving animals. Many of these species take time to spread and need many life cycles to bridge the distance covered by an ecoduct. All these improved migration options will result in qualitative enhancement of the overall population and the dynamics of these populations. Long term effects include increased genetic diversity of plants and animals resulting in resilient populations, and enhanced seed dispersal by migrating animals through a larger area resulting in enhancement of the habitat. In addition, we believe that these green bridges will not just improve migration opportunities within Zuid-Kennemerland (South Kennemerland) but in the Dutch

coastal zone as well. Animals expected to migrate due to climatic warming will find migration options to the north facilitated. Green bridge Zandpoort The first green bridge in the Zuid-Kennemerland (South Kennemerland) region was finished late 2013. It is called Zandpoort and is the most southern one, located near the village of Zandvoort. To evaluate the effects of the green bridges, a monitoring programme was designed in which insects, reptiles, amphibians, mammals and even snails were all counted. The programme was launched in early 2014 and will run for five years. The first results are promising and indicate the establishment of several key species like bluewinged grasshopper (Oedipoda caerulescens) and queen of Spain fritillary (Issoria lathonia). Future In 2016, the two other green bridges (Duinpoort and Zeepoort) will be finished. They will reduce the fragmentation of our dune landscape in a major way and will improve the overall landscape quality. Roe deer (Capreolus capreolus) and rabbits crossing busy motorway and railways will be facilitated. Furthermore, niobe fritallary (Argynnis Niobe), blue-winged grasshopper and many more key-species will find new homes on the green bridges, and populations of these type of insects on either side of the green bridge will then be connected naturally. Dick Groenendijk, PWN consultant Conservation


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