Predation and death

Death as part of nature

Death of large grazers is mainly because of:

  • diseases and food shortage
  • hunting by men
  • predation by predators
  • force of nature

Diseases, often caused by lack of food, are by far the major cause of death. In the Netherlands, predators have little influence on large grazers, and the forces of nature hardly ever lead to massive mortality as wildlife supervisors often intervene. Carcasses that are left behind play a crucial role in the natural cycle: when there is death, there is hope!


Diseases and lack of food

Diseases will have more impact when the number of grazers (density) increases in an area: the animals infect each other more easily: directly or indirectly through manure, among other things. Moreover, high densities also cause food shortages and animals weakened by hunger are more prone to diseases. This is why large areas and low densities are important for the grazers' health. But even when densities are low it can happen that old, weak or sick animals do not profit from the available food and will be so weakened that disease and parasites can be fatal for them. The re-wilding process of horses and cattle also means that they will build up an immune response to diseases. They learn to deal with their food supplies more efficiently, to eat herbs and avoid poisonous plants. It is essential that natural selection mechanisms can do their work to such a degree that the herd stays healthy. ARK staff try to reduce intervention to a minimum if the animals are ill, but when they must it is aimed at curing the animals or removing the sick or the weakened.

Hunting by men

Large herbivores are often culled to prevent overpopulation and diseases. However, the criteria for culling are different from natural pressures by predation. The majority of prey of natural predators consists of young animals, whereas they are spared in the shooting season. Hunting and shooting also carry the risk that animals become shy of people, which is a demerit for nature areas. We know roe and deer as shy nocturnal animals, but they are often observed in daytime and in open fields (as in the Oostvaardersplassen) where no shooting or hunting take place.

Predation by predators

The larger the grazer, the less it has to fear from predators. Predation hardly carries any weight on the number of grazers, but predatory animals do positively influence the health of herds, and their behaviour and range of distribution. For these reasons, ARK would welcome the introduction of larger predators. Additional measures will be necessary for the protection of these predators, such as a hunting ban and strict monitoring for fear of poisoning. The last decades, the number of large predators has been on the increase in Western Europe, and the Netherlands may benefit from it. The most important species:

Wild cat

It mainly preys on animals up to the size of a hare and could take a young beaver or an abandoned calf. It currently has reached the boundaries of its range of distribution in the Ardennes within a stone's throw of southeast Netherlands. Their numbers have tripled in Germany in the past ten years. In 1999 and 2003, a dead and a live wild cat were found in the Netherlands in the Ooijpolder near Nijmegen and in central Brabant respectively.

Fox

For its size, the fox may be able to attack an abandoned young calf and must be able to handle a young beaver. In spite of being intensively chased down by men it managed to maintain itself and expand. It shows great ability to adapt itself to our culture. Their numbers are on the increase in almost all thinkable areas and terrains, even in the centres of large cities. The fox has not been seen in some of the West Frisian islands.

Sea eagle

When speaking about the large grazers, we should see the sea-eagle mainly as a carrion bird. They often feast on dead red deer in the Oostvaardersplassen. During the pesticides era, wintering sea eagles were fed on poison-free carrion by Scandinavian conservationists for decades and narrowly escaped extinction in Europe because of the impact of DDT and other harmful agricultural pesticides. Now that the environment has become cleaner, this bird of prey is flying high again. Over four hundred pairs are now nesting in Germany and their range of distribution is extending this way.

Lynx

Lynx is specialised in the chase of animals up to the size of a rabbit or hare, but it may catch roe deer, young red deer and young wild boar. There have been several sightings in south and central Limburg in the last decade. They may have come from re-introduction programmes in the German Eiffel area and there are now small populations in our country and in the Ardennes.

Wolf

Adult deer, horse, cattle, elk and wisent, they all had everything to fear from of wolf as their natural enemy in Europe. A healthy herd can defend itself perfectly, but young solitary and weakened animals do run a risk. Though we haven't seen them in the Netherlands for over a century, the wolf is undeniably regaining territory in Europe. Various wolf families are living in eastern Germany and it is expected that the species will expand towards the west. Wolves are making a comeback in France as well.

When there is death, there is hope!

In the Netherlands, red deer, roe deer and beavers that have died a natural death can be left in the field. Such large carcasses prove to be a source of life: boar, fix, raven and sea eagle are content with them, and dozens of species of flesh flies, ants and scavenger beetles. The latter are hunted by the Devil's coach-horse beetle and the digger wasp. Fungi and bacteria eventually cause the release of essential minerals from the carcasses, like phosphor and calcium, to be returned to the soil from which plants draw their nutriments.


The Livestock Act versus Natural Processes

The law does not (yet) see horses and cattle as game but as livestock for which we have the duty of due care. That is the reason why cattle in nature areas are kept free of brucellosis, leptospirosis, bovine TB and bovine rhinotracheitis (IBR). The carcasses of horses and cattle are not allowed to be left behind in nature areas but are moved for destruction as prescribed by law. The large Dutch livestock count and the ensuing economic interests make it understandable that no risks are taken, but the balance has tipped too far. By safeguarding the Netherlands completely from relatively harmless diseases like IBR, we weaken the natural defence system of cattle. This will not help their health in the long term. It would be quite responsible to let carcasses decay as part of the natural cycle in vast nature areas with broad buffer zones between cattle farming areas. 

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