I covered Oostvaardersplassen multiple times on this blog, but never the ecologic dimension of the reserve as a whole. Oostvaardersplassen is often praised as a new wilderness, f.e. in the documentary “De nieuwe wildnernis” from 2013. Others have claimed it is a failed case of rewilding.
Oostvaardersplassen, located in the province of Flevoland in the Netherlands, is a fenced area of 56 square kilometres. In 1983, 35 Heck cattle were introduced, followed by 27 Konik ponies in 1984 and 54 red deer in 1992. The number of the animals was not regulated and there also was no supplementary feeding. In the early 2000s, the number of cattle reached its peak of about 1000 animals, and after that, started to decrease again while the number of horses and red deer started to increase further. As of October 2017, there were 230 Heck cattle, 1040-1060 Koniks and incredible 3910-3990 red deer in the reserve (go here). It has to be noted that the largest carnivore in the reserve is the fox, while there are no lynxes, bears, wolves and of course no lions which would be the natural enemies of grown bovines and equines.
What is very interesting is the drop in the number of cattle. It is very likely that the cattle are outcompeted by geese [1] and possibly also horses, because both can graze a few centimetres deeper than cattle [1,2]. I would not rule out that the cattle may one day disappear from the reserve because of that. If that is the case, how did aurochs coexist with these animals? One possible explanation would be so-called predation-mediated coexistence. Adult aurochs were possibly less easy to kill for wolves and even lions than horses or deer. Thus, these predators would reduce the population of these animals more than that of the aurochs, and therefore enabling coexistence between these species.
Roe deer already disappeared from the reserve, perhaps outcompeted [3] (that’s what the literature says; however, I recently saw a video from OVP that shows a roe deer in the reserve).
The original natural population density of large herbivores in Europe without human influence is unknown. But the fact that the avifauna in the OVP has declined by 36% since 1997 [3], as well as the drastic reduction of cover from woody vegetation from 30% to less than 1% from 1996 to 2011 [4] may suggest overgrazing in OVP.
The OVP should be regarded as an artificial system rather than a nature area, in which some of the native large herbivores are present (red deer, cattle, horses) and others are not (roe deer, wild boar, elk, wisent) [4] and, more importantly, no predators for adult deer, cattle and horses. Because the area is fenced, the large herbivores are unable to migrate and the area is basically an island – an island devoid of predators. The reduction in avifauna diversity and decrease of habitat diversity in the reserve as a consequence of the intense grazing pressure caused by the very high density of the herbivores as a consequence of the lack of predators, as well as the disappearance of roe deer from the reserve suggest that the OVP anything but a “natural” ecosystem. It is as if one would fence an area in the Serengeti, kill off all the predators, watch some herbivore species reaching very high densities while others disappear, and a loss of habitat types and an accompanying loss of species diversity in that area.
In the Yellowstone reserve, the reintroduction of wolves has shown to have an impact on herbivore activity and population density, which in turn influences the vegetation [5]. A reintroduction of predators in the OVP is unfortunately out of question, as the surrounding area is densely populated and farmers would have to fear for their livestock.
Some consider the OVP because of all that a “failed case of rewilding”. Regardless of if this is true, it is still very valuable as a dedomestication experiment. There are hints that the Heck cattle population in the OVP, which has been exposed to selective pressure for 40 years now, is evolving (go here or here).
Literature
[1] Cornelissen et al.: Rewilding Europe: Early dynamics of a multispecies grazing ecosystem.
[2] Bunzel-Drüke et al.: Praxisleitfaden für Ganzjahresbeweidung in Naturschutz und Landschaftsentwicklung – “Wilde Weiden”. 2008.
[3] van Vuure: On the origin of the Polish Konik and its relation to Dutch nature management. 2014.
[4] Cornelissen et al.: Effects of large herbivores on wood pasture dynamics in a European wetland system. 2014.
[5] van Vuure: Retracing the aurochs – history, morphology and ecology of an extinct wild ox. 2005.
Not too long ago the plan was to connect the OVP through wildlife corridors to Het Horsterwold (the woods near Zeewolde) and from there over a wildlife bridge over Het Nuldernauw so it could be connected to National Park the Veluwe. From there all the major parks would be connected to each other and across the border to Germany and Belgium through a plan called "Ecologische Hoofdstructuur" (Ecological Main Structure).
ReplyDeleteThe plan was pretty far along and budgeted for until a business oriented libertarian/conservative party called VVD became the leading political party in government. They didn't prioritise nature and the plan was nixed.
The plan woul've been finished by now if it had went ahead and with the recent natural return of the wolf in the Netherlands the picture would've been complete. But oh well, this is why we can't have nice things... :(
It is worth noting that, while wolves have certainly had a significant effect on some herbivores in Yellowstone, especially wapiti, they have had a far less significant effect on others. Bison, for example are not regulated by wolves and show no evidence of avoiding areas with wolves. Their population is rising and they are suspected to still be well below ecological carrying capacity of the park, though well past the socio-economic capacity. Bison in Bialowieza are similarly not regulated by wolves and it would seem the only herbivores there that are regulated are red deer, similar to wapiti in Yellowstone. It is possible that lions (and possibly hyenas) would give some advantage for bovines over equines. In Africa cape buffalo are the sixth most predator-resistant megaherbivore after the elephant, two rhino species, hippopotamus, and giraffe. There are, however, systems where buffalo are not regulated by lions, but instead by disease and food. Apparently habitat productivity has a lot to do with it, with buffalo being more susceptible to predatory regulation in systems where food and water are not limiting factors. Zebras seem to be limited by lions regardless, possibly because they are less sensitive to food quality.
ReplyDeleteIt might be food preference from the predators that keep limiting the zebras. In Kristiansand Zoo (Norway), the staff I spoke to told me the lions (when given a choice) prefer horse over any other food. The tiger in comparison, would take deer, cattle or even chicken over horsemeat.
DeleteThis may just be the particular animals personal preferences though, and not that of the whole species. Lions, like any other animal, have their own personality traits.
Some lynx (individuals) in Eastern Europe are specialized on red deer, even taking down adults. A couple could well live in the 56 km2, but it requires tree cover and yes, the sheep may be tempting for them as well.
ReplyDeleteRecently the dutch tv show 'vroege vogels' did an episode about the OVP. In the show they announced new plans for the nature reserve. One of the measures that will be taken are the shooting of large numbers of horses and red deer to get a more diverse vegetation and an increase in species diversity. This was partly due to the increasing complaining of bird watchers who saw the number of bird species decline sharply. Personally i am very interested in the impact this will have on the area and of course the heck cattle that are present in the area.
ReplyDeleteOn iNaturalist, observations of roe deer and wild boar have been reported within OVP, so those are two more herbivores to add to the list. The only way that I can see OVP being somewhat sustainable is if the Red Deer population is cut in half (either with exporting or with culling/selling of meat), if large native trees are planted in certain areas to make a mosaic hardwood forest, and if it is expanded as much as possible (either expanding the borders or creating more land area within OVP). As for reintroducing predators, the only candidate that I can think of is the Striped Hyena. They are scavengers and hunters, and are not very territorial (so two family groups might be able to share OVP if enough food is present).
ReplyDeleteCorrection: the sighting of a Wild Boar was very close nearby, but not actually within the reserve. There are two roe deer sightings in the reserve itself. I would also suggest adding a few Fallow Deer once Red Deer numbers are reduced and a Forest can be replanted.
DeleteForest planting isn't the way to go here. The appeal of large herbivores in the OVP is that they prevent forest regeneration, creating a large floodplain suitable for waterbirds. Predator introduction (wolves ideally, and not confined to the reserve) might reduce red deer numbers (but probably not horse or cattle numbers) allowing for some natural regeneration of trees, but it would be a great shame if the whole area became another forest.
DeletePiernas relativamente largas, tronco relativamente corto, cuernos finos y no muy grandes pero bien orientados, color incorrecto:
ReplyDeletehttps://yeguadamor.com/index.php/vacas
I think that "rewilding" in Western Europe can at best offer a more or less successful simulation of wilderness. I can only confirm your information on OVP from decades of observation - most recently last week. From the number of large herbivores perceptible from the observation points, one could conclude that the red deer population has also been "adapted" in the meantime. Earthworks are being carried out on the area, which is now almost completely free of trees - presumably for planting woody plants. Large areas in the area have been closed off with fences.
ReplyDeleteI remember a lecture by Frans Vera, who always defended the original concept (no regulation measures). He said that starvation was the most common cause of mortality among large herbivores in the Serengeti, too. In any case, politically this was probably not tenable in OVP?
What is missing for a "real wilderness" in OVP is above all the area factor. Not only is it too small for populations of large carnivores, it also prevents migratory movements of herbivores. We know this in (almost?) all herd-forming wild grazing animals. In Central Europe, too, they probably occurred as an adaptation to seasonal changes. And in the seasonally comparatively stable areas close to the Atlantic, other factors such as insects may have played a role. Here I refer you to a video recorded in a Belarusian "jungle". It shows how much herbivores suffer from insects in the summertime https://www.youtube.com/watch?v=Erb2RmvzjWI. Something similar is known from the Camargue. There, too, cattle and horses would probably move to higher ground if they could. However, the temporary absence of the herds due to migration leads to a break for the vegetation. This probably results in higher biodiversity. In the case of "island situations", however, regulation of herd populations is likely to be indispensable.
actually the decrease in biodiversity mostly was because of the decrease in biodiversity in the swamp area. the swamp area is maintained a reetland by geese who are dependent on grasslands which is why the large herbivores are there in the first place to maintain the grasslands for the geese. but the water system of the OVP was closed, and this ment there were little water dynamics which created less diversity in the swamp vegetation. this lead to less diversity in the bird life which caused the drop in biodiversity. the claim that this is caused by large herbivores is false. the 2 arent related. now the state forest department has been working on a swamo reset in the reetlands. they are doing it for a couple of years now. they first pumped a lot of water out of the swamp creating a lot of new sproutings and are now refilling it with water again to protect the plants and fish again. this will solve the biodiversity
ReplyDeletethe park is big enough for wolves if we consider the connected forests and grasslands who are connected for all animals exept the heck cattle and koniks. the area is big enough for a wolf pack if we consider how big the density of prey is. a max of 5000 prey big prey animals in a 60 square kilometer park is more than habitable. best would if the Oostvaardersterwold gets realized and the get doubled in size with the connection of the holsterwold forest. this forest is near the oostvaardersplassen and is inhabited with fallow deer, roe deer and koniks. the forest also would mean a proper connection with the largest forested area of western europe which is the veluwe in the netherlands
ReplyDeleteplus the veluwe already has multiple wolf packs and can possibly host lynx'populations also the area already has small populations of wild cattle like sayaguesa and very proper looking wild highland cattle. also some icelandic hores and lots of red deer, wild boar, fallow deer and roe deer
DeleteThe aspect with the swamp biodiversity is interesting, do you have a source or a paper for that?
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