You may have heard of the Dutch rewilding experiment: horses and other large herbivores free roaming in a nature preserve, to reconstruct prehistoric ecosystems. theguardian.com/environment/20…
I've been following this story with interest, as it's one of the few rewilding experiments to include large herbivores. One of my research areas is the ecological impacts of losing ice age megafauna, like mammoths.
What's happened at the Oostvaardersplassen? It's complicated, and I've never visited this site, but I have some preliminary thoughts (@JCSvenning, I'd love to hear yours, too).
In this preserve, animals aren't fed any supplemental material. It's as "natural" as possible. Three warm winters allowed megafaunal populations to boom. Then, in a harsh winter, thousands of animals have died.
Starvation happens in nature, all the time. The Oostvaardersplassen is not a zoo; we should expect some of this to happen. But the Oostvaardersplassen is also not completely natural -- it has fences, and no native predators (to my knowledge).
In a natural setting, large animals do definitely starve all the time, sometimes in very large numbers. But their populations are also kept in check in part by predators, and they can usually also migrate to other regions to find food or water in hard times.
There are some conflicting frameworks at work here: animal rights and ecology and conservation can be at odds with one another over animal suffering. Think about nature videos where animals are starving, or hunted, or injured. It's natural, even though it's hard to watch.
From an ecological perspective, as terrible as it is, sometimes animals starve to death, get sick or injured, and suffer. From an an animal rights perspective, suffering must be alleviated and prevented (at least for captive animals).
Why does this framework distinction matter? Because a lot of how we interpret what happened at the Oostvaardersplassen comes down to whether we think this is a "natural" system or not. There are fences, but are they captive animals? Are they wild?
Is this die-off an unfortunate but very natural process? Or is it a preventable tragedy born of neglect or mismanagement? Or something in between? And what does this mean for rewilding, generally?
I still stand behind rewilding as a conservation tool. But the Oostvaardersplassen raises important questions about the level of active intervention needed, especially in the absence of native predators or finite resources (including available area for rewilding).
I've worked at @KonzaLTER, a remnant tallgrass prairie with a reintroduced herd of bison. They cull the herd every year to maintain a healthy population size, based on the carrying capacity of the site.
Often, our efforts at restoration must involve a lot of hands-on management. You often can't just dump species in a wild space and call it a day. This can make people uncomfortable, because we want "nature" to be "nature" (read: non-human).
I don't think the Oostvaardersplassen means we should give up on rewilding efforts. But we need to be thoughtful about how we implement it as a scientific community, and we need to think about messaging when it comes to communicating the less cute and cuddly sides of nature.
