The Oostvaardersplassen nature reserve is in the Flevoland province of The Netherlands, even at 56 square kilometres is just a small part of the 430 square kilometre Polder Zuidelijk Flevoland. The Polder was reclaimed between 1959 and 1968, is just east of Amsterdam and is now home to over 200,000 people as well as agricultural land and of the course the Oostvaardersplassen nature reserve.
It’s stand-alone importance as a nature reserve for the preservation of wetland birds is internationally significant but it is most well-known now for the ambitious re-wilding efforts that have taken place there. This re-wilding has relied heavily on the introduction of large herbivores as architects of a sparsely wooded open habitat which has prevented to some degree the succession of scrub and woodland on a valuable wetland habitat. This has maintained a fairly open landscape not dissimilar to a plane but as the reserve is entirely enclosed by a fence and there are no apex predators or opportunities for these herbivores to migrate the reserve has also faces some harsh criticism on animal welfare grounds.
What became the reserve was originally earmarked for industrial or agricultural use but when it was not immediately utilised it soon became a wetland of open water and marsh vegetation and was visited within just a few years by thousands of wetland birds that hadn’t been seen there before in such great numbers. Biologists working for the ministry of Infrastructure and Watermanagement (the organisation responsible for the design and construction of the polder) soon realised that the area was of major importance for wetland birds and in 1975 the area was given temporary nature reserve status.
In 1986 it was officially designated a nature reserve for the preservation of wetland birds and later as a special protection area for wetland birds according to the European Bird Directive and as a RAMSAR wetland site in 1989. In 2010 it became a Natura 2000 area for the protection of 31 wetland birds. In 1983 2000 hectares was added to the initial 3500 hectares reserve, this area was a ‘dry’ zone of grass and tall herb species, reeds, shrubs and trees and provided forage and nesting sites for some of the protected bird species present on the reserve such as geese, herons and spoonbills. This zone was managed to provide these specific habitats for the birds and formed a border around the reserve.
As well as the addition of this 2000 hectares 1983 was also the year the first of the larger herbivores were released into a small part of the reserve and the re-wilding began. These first introductions included Heck cattle and Konik ponies. The Heck cattle are about as close as we get in the modern day to the extinct Aurochs which once roamed the plains of Europe and Asia and the Konik’s are related to the Tarpan, the last species of wild horse which are now extinct as well. The original populations of 32 cattle and 20 pony’s have exploded to a total population which now numbers in the thousands. They were followed in the 90’s by an introduction of 54 red deer whose population has also grown significantly.
This reintroduction was largely the work of Franz Vera a Dutch biologist and ecologist, it wouldn’t be an exaggeration to say the Oostvaardersplassen is Vera’s life’s work. He worked hard lobbying the Dutch government for the creation of the nature reserve in the first place and again for the release of the range of herbivores that can now be found there.
What these re-introductions have led to is the creation of a reserve that has been referred to by some as ‘the savannah behind the dikes’ in reference to the herds of large herbivores and the reserves resemblance of African planes. They have also led to a significant amount of criticism of the reserve. As the re-introduction of herbivores wasn’t accompanied by an introduction of any predators, the reserve is completely enclosed by a fence and, at least initially, there was a policy of complete non-intervention by humans populations rapidly increased to the point that a significant number of animals starved to death.
The argument that starvation is a natural process and occurs even where there are predatory species is a strong one but the scale on which these animals was starving was unprecedented and caused significant public backlash. There were several occasions where police had to disperse people who were throwing food into the fenced reserve to feed the animals. In a fully functioning ecosystem natural death due to starvation and disease does of course occur and the bodies of those animals supports a whole host of carrion feeding mammals, birds and invertebrates and would form part of a natural ecosystem and support biodiversity that is often lacking from the European landscape in a day and age of industrial agriculture and land management.
An additional benefit of the large populations of herbivores and the main benefit that was hoped for after their introduction was that there grazing would limit the succession of scrub woodland and shrubs and help, along with the grazing of migrating and resident geese and other wetland birds, to maintain an open landscape and retain the integrity of reedbeds and wetland habitats. Some patchy woodland did establish itself as would be expected and this type of habitat was a significant inspiration to the Knepp estate in Sussex where a similar mix of species has been reintroduced and where it was found that while grazing herbivores did maintain a lot of open ground ‘nursery’ areas formed from thorny shrubs protected some trees and allowed small patches of woodland to establish forming a woodland pasture habitat.
As one of the first deliberate re-wilding projects the Oostvaardersplassen has been an inspiration to other projects as much as it has been a success in it’s own right and has given us a phrase that the Dutch have been using to describe what has occurred at the reserve. The phrase is “new nature” and what better phrase to describe what we see at Oostvaardersplassen or many of the other re-wilded reserves around the world.
The land at the Oostvaardersplassen is ultimately new, once sea the prevailing habitat of it’s surroundings would once have been lowland heath and what we see at the reserve is very much a wetland habitat, perhaps without as much grazing some of the dryer patches of the reserve would eventually become heath, and perhaps without the grazers it would become woodland but that’s the beauty of the project and this idea of “new nature” nature is being allowed to take it’s own course, eventually the reserve may be linked to other nature reserves in Holland through corridors of reclaimed agricultural and industrial land which can be integrated into the reserve and we may see the return of predators and other species and some of the fences will come down but what is clear is that this projects reach goes far beyond the reserve and beyond Holland and it is inspiring rewilding all over the world.