Why the Oostvaardersplassen rewilding scheme may have missed the mark

Recent years have seen a movement towards “rewilding”, the process of giving land back to natural processes. As it stands, rewilding is understood to be highly positive for the climate, biodiversity, and the wallet; since minimal human intervention results in almost no fuel output, no hi-tech re-routing of rivers, and no chemical fertilisers – not to mention no mass deforestation! Vitally, rewilding allows for new ecosystems to establish themselves securely, and for regionally extinct species to re-emerge. 

This is exactly what has happened at the Oostvaardersplassen, a rewilding site established in the Netherlands during the late 80s. Having previously been extinct in Western Europe, White Tailed Eagles have been recorded at this site alongside around 250 other species of bird. However, the success of the Oostvaardersplassen in this respect is largely due to grazing animals, the introduction of which to the site has proven controversial for animal rights activists, ecologists, and among public opinion.

Location of the Oostvaardersplassen, Netherlands. Image: Google Maps.

Grazing animals have been the keystone species in transforming the Oostvaardersplassen, once largely submerged, into its current grassland. Grazing animals have historically been integral in establishing varied habitat and grasslands through their intensive management of vegetation; this is why the vegetation doesn’t reach “climax”, which is where unkempt land eventually turns into woodland. This was the idea behind maintaining grassland at the Oostvaardersplassen, which now boasts herds of hardy breeds such as Konik ponies, Heck cattle, and Roe deer, valued for their similarities to ancient breeds (for example Aurochs) who once excelled at the job. The introduction of grazing animals also promotes biodiversity in other respects: cows can transport around 230 plant species in their gut and hair, and under-grazed areas promote the growth of shrubs and other flora, which in turn attract insect species such as butterflies. 

Allowing natural processes to take over in the Oostvaardersplassen means human intervention is minimal. Frans Vera, the ecologist who spearheaded the Oostvaaedersplassen since its conception, considers some of the positives to this; including how the animals have natural herd structures and mating processes (without artificial insemination). 

An aerial view of the Oostvaardersplassen, Netherlands. Credit: Sky from Above Drone.

However,  the so-called “seasonal dieback” of these grazing animals has proved controversial. Herd populations are heavily contingent upon the seasons so weaker animals are left to die out and struggle through harsh winters. The winter of 2017 was met with particular outrage from animal rights activists after 3000 deer, horse, and cattle died.  Central to the activists’ arguments is that these deaths were unnatural because of  the Oostvaardersplassen’s perimeter fence which, activists claim, prevents migration and the natural movement of animals to find food. Crucially, plans to establish a nature corridor to  the Oostvaardersplassen also collapsed. Protestors now throw hay to animals over the fence and have organised vigils, as well as sending some *interesting* paraphernalia to Vera. 

Part of what makes the Oostvaardersplassen’s death toll so harrowing is that deer carcasses, which aren’t legally required to be incinerated, are left on the grassland. These are left as part of the site’s non-intervention principles, and also for necrophagous insects (those who draw vital nutrients into the soil) to feed on. Yet, it is certain that these carcasses, deemed to make the Oostvaardersplassen resemble a “cemetery”, bring animal deaths into a clarity many struggle to reconcile themselves with.

As a consequence, tensions between nature lovers are brought into view. It’s undeniable that the Oostvaardersplassen has been successful at promoting a number of new species, undermining the idea of climax vegetation, and revitalising various ecosystems. However, navigating this with the high risk of alienating the public and activists  is problematic. Although Frans Vera resents public outcry, stating that “the fixation is solely on [the animals’] death not on the quality of their lives”, it appears a compromise must be met. Since the winter of 2017, the number of grazing animals allowed at the Oostvaardersplassen has been capped to prevent overpopulation, as out-of-control population growth is largely considered the reason behind the mass mortalities in 2017.

Complete non-intervention is now an unviable path forwards for the Oostvaardersplassen. Intervention is necessary in two ways; both to placate public opinion, and to prevent unchecked animal populations. Moreover, Frank Berndese, a former professor of ecology and conservation, has also observed that the very principle of the Oostvaardersplassen has been rooted in intervention via the prevention of woodland succession and maintenance of the grassland. These have been strictly engineered by the introduction of grazing animals. Thus, a fallacy in rewilding is exposed. What the Oostvaardersplassen lays out clearly, however, is that non-intervention is always calculated, both by public and natural forces. 

By Mia Fulford

Header image: NOS