2024-02-11 20:21:19
They had too many in a river dune near Lexmond, while there were too few in the Amsterdam Water Supply Dunes. That is why the first 22 rabbits were moved from river dune to coastal dune last month. ‘Rabbits bring variation back to the landscape.’
“It is almost encouraging that it still exists in the Netherlands: a nature reserve where damage is caused by too much rabbit feeding!” Biologist Jasja Dekker is not the man for gloating, but after all these years with only sad stories about disappearing rabbits, he can clearly enjoy a nature reserve where they apparently have too many.
“The rabbit population has been decimated in many places, especially due to the viral diseases myxomatosis and Viral Hemorrhagic Syndrome (VHS). So yes, I am surprised by a nature reserve of only seven hectares where more than a thousand rabbits hop around.”
That rabbit paradise is called Luistenbuul and is a river dune in a loop of the Lek, just above Lexmond. “We indeed have too many rabbits here,” agrees ranger Mirjam Eikelenboom of Het Zuid-Hollands Landschap. “Apparently there is a lot of things here that the rabbits find very attractive, because they do not leave en masse to the areas around them.”
Mother Nature has also not yet intervened in the relatively high status of the rabbits. While viruses have decimated rabbit populations in other areas, the population in Luistenbuul has always recovered quickly. “This is apparently a hidden gem, not only for human visitors,” the ranger notes matter-of-factly.
Love-hate relationship with rabbits
Yet Eikelenboom has a kind of love-hate relationship with the rabbits, it seems. “By digging, they ensure that the calcareous sand of the river dune continues to surface. Plants such as yellow bedstraw or soft stonecrop love this. Partly because of this valuable ‘stream valley flora’, this small area has been designated as a Natura 2000 area. But in addition to digging, they also graze. And with so many rabbits, that means that many of those valuable plants don’t even get the chance to grow, let alone form seeds.”
Instead of waiting for ‘natural balance’ or an unexpected virus outbreak, Eikelenboom and colleagues decided to take matters into their own hands. “Nature management in the Netherlands simply means: active intervention in a number of cases. That is why we caught the first 22 rabbits this winter, in collaboration with rabbit expert Dekker and with the help of a ferreteur.”
“The catching is very controlled and animal-friendly,” says Dekker. “Frette owner Michael Moerman and his father Paul have been catching rabbits for a long time using tame, tagged ferrets. First they map an entire castle and close all exits with net. Sometimes there are as many as forty back doors where you have to add some extra people.”
“If a ferret is sent in, the rabbits should flee from the castle and we can immediately release them from such a net. If there is no response, for example, a rabbit may be standing opposite the ferret in a dead-end hallway. Moerman then quickly digs the ferret out again with the help of the transmitter signal, to prevent the animal from attacking the rabbit.”
Catching rabbits is not easy
Dekker’s story sounds slightly simpler than the reality, he must admit. “Catching was not easy. The castles of the Luistenbuul were really enormous and that was difficult to capture. Then the rabbits continue to avoid the ferret underground. That’s why the counter eventually got stuck at 22.”
These 22 animals were released last month in the Amsterdam Waterleidingduinen, where they were welcomed with open arms by ecologist Luc Geelen of Waternet. “The rabbits have completely disappeared from most of our dune area, mainly due to viral diseases. There is only a small population in the western part of the area. But in the meantime, those rabbits can really add something to the landscape. With their digging and grazing they make the landscape more varied, which in turn benefits many plants and animals. So we would like to have them back, also in the other parts of the dune.”
The Amsterdam Water Supply Dunes have mainly been in the news in recent years due to the large number of fallow deer in the area. They have been hunted for several years, but there are still more than twice as many deer than the 800 that biologists had calculated as ‘ecologically responsible’. The forest rangers in the area complain that hardly any flowers bloom due to the violence of all those grazing deer.
However, Geelen already thinks it is responsible to add additional grazers in the form of rabbits. “Next year we hope to reach our target number of 800 fallow deer. Then now is the time to work on a varied palette of grazers. Every grazer grazes differently and therefore has a different effect on nature. Rabbits really belong in the dunes,” says Geelen.
Rabbits graze very drastically
For the rabbit relocation to be successful, it is essential that the population of fallow deer is further reduced, says biologist Dekker. “Different grazers have their own effect. Cows graze very coarsely and leave long tufts, and with a wandering flock of sheep you can graze very specifically. But fallow deer and rabbits look a bit alike; they both graze very drastically. They really measure the plants. So if there are a lot of fallow deer walking around, there will be less left for the rabbits,” says Dekker. “I suspect that the amount of fallow deer in the area will not have helped the rabbit population in any case.”
Bird researcher Herman van Oosten, who was not involved in this project, can understand the wish of the managers of the Waterleidingduinen to bring in more rabbits. “With their grazing, rabbits provide short vegetation around the burrows. Further on, the grass can in principle grow a little higher again. That variation is very good for insects, which is good for insect-eating birds such as wheatears. And those wheatears also need old rabbit holes to make their nests. Fewer rabbits and rabbit holes also means fewer opportunities for wheatears, which we see very few in the Netherlands.”
Van Oosten has also experimented with buried nest boxes for wheatears in other areas, such as the dunes near Castricum. That also appears to work well. “At one point I had three breeding female wheatears in the Vogelduin near Castricum, all three of whom were in a nest box, while rabbit holes were also available there. But apparently the birds realized that you are safer in such a box from foxes that can dig out your nest.”
Nevertheless, Van Oosten thinks that fresh rabbit holes in particular can support the wheatear population in a more natural way. “And I also think that the Waterleidingduinen are somehow attractive to the wheatear. They have now completely disappeared from the Vogelduin, but a few years ago I still had a lonely male there that was singing in vain. The only female from the Vogelduin, which I could recognize by the colored rings around her leg, was attempting to breed in the Waterleidingduinen at that time. So the potential is there,” Van Oosten notes.
Nice dinner for the hen harrier
In addition to new wheatears, biologist Dekker also hopes for birds of prey such as the hen harrier. “That’s a typical rabbit eater,” he says. “And just like the wheatear, the hen harrier has disappeared from many areas in our country.”
To prevent the relocated rabbits from also falling prey to myxomatosis or VHS, they are vaccinated before being released. And to get them used to their new environment, Waternet has built a traditional ‘warande’ with the help of volunteers. That is a large type of run, in which rabbits used to be kept.
“But apparently a few rabbits couldn’t wait for Waternet to open the run after a few weeks. On infrared images from the camera placed near the run, we at one point saw a rabbit climbing over the high fence. If I hadn’t seen it myself, I would never have believed it!” says Dekker.
As far as ranger Eikelenboom is concerned, it does not stop at this one-off capture. “Of course, out of a thousand rabbits, you won’t notice anything if you catch these 22 animals. After the maternity season, we hope to catch even more rabbits in order to lower our numbers and increase them in the dunes.” Waternet has a permit to move animals to the Waterleidingduinen for five years.
Despite the almost proverbial speed at which rabbits reproduce, Dekker thinks it should be possible to tackle the nuisance in Luistenbuul. “If several hundred animals have been removed after five years, it can really make a difference in the river dune. And hopefully with those few hundred animals in the Waterleidingduinen you can reach just above the critical limit that is necessary to maintain an independent population again.”
Also read:
In the Middle Ages, rabbits were not the sweet, cuddly creatures that they are today at Easter
Walk into a supermarket and you know that Easter has nothing to do with Christianity, but is a festival with hares. And thanks to Youp van ‘t Hek’s classic Flappie, Christmas is definitely linked to rabbits.
Vlieland brings rabbits from the Maasvlakte to its own dunes
The rabbit population on Vlieland was increased by a quarter at the beginning of this month by releasing 26 animals. The rabbit plays a key role in the dunes, but the population has been weakened by disease and grass growth. Will the newcomers make it?
1707831294
#relocation #rabbits #saves #coastal #dune #river #dune