In my previous article I covered the basics of rewilding. What it is, and why there are some problems in achieving it. This time, I’m going to talk about instances where passionate individuals and organisations have, rightly or wrongly, forged ahead with animal introductions.
In the United Kingdom, our only controlled mammal reintroductions to date have involved the beaver, which succumbed to hunting pressure in the 16th century. The first official trial began in Knapdale, Scotland in 2009, but there are now several populations across the country including one in the River Otter in Devon and one at Wildwood in Kent. In all cases, beavers appear to have had a positive impact on biodiversity and the landscape. It’s hoped by many that beavers will soon be found nationwide, when they will be expected to aid in conservation and habitat management projects, and maybe even reduce the risk of flooding to much of the UK!
Similar success stories can be found around the globe. Oostvaardersplassen, a nature reserve in the Netherlands, was reclaimed from the sea in 1968. When it was found to be unsuitable for farming, the land was left to become a wildlife haven. The release of Heck cattle and konik ponies to graze the land has led to the development of ecological functions rivalling natural sites. Oostvaardersplassen is now an extremely valuable EU bird reserve, with white tailed sea eagles recently reported to be breeding there.
If we move further East, we find Pleistocene Park in Russia. Here, Sergey Zimov has pioneered the introduction of herbivores such as Yakutian horses to otherwise unproductive Tundra. This experiment began in order to support the idea that overhunting wiped out the Pleistocene fauna. Zimov believed that introducing herbivores to Tundra would create productive grassland similar to that which once sustained mammoths.
Many people were sceptical but now, over 20 years since the first introductions, science appears to be proving him correct. It seems that, by stomping down moss and eating the grass that grows in its place, the herbivores are indeed converting the Tundra to a grass steppe. As well as helping to answer fundamental questions about our ancestors’ roles in Pleistocene extinctions, this experiment is also helping to quell climate change. It seems that by removing moss and creating grass instead, the animals of Pleistocene Park are slowing the carbon-releasing thaw of soil permafrost. In future, Zimov plans to add further herbivores, Siberian tigers and, if science allows, woolly mammoths to the system!
Returning to more traditional rewilding, we can’t ignore Yellowstone. It is well-known (thanks to a certain Youtube video) that wolves were reintroduced to Yellowstone in 1995, after 100 years of absence. Once released, the wolves began extensively hunting the out-of-control elk population, which had a knock on effect (known as a cascade) to other parts of the food chain.
With elk numbers reduced, young saplings could grow without being nibbled down at every opportunity. Aspen trees, which had been declining for years, suddenly began to reappear. Grizzly bear numbers increased too, with the wolves making it easier for the bears to scavenge leftovers. Perhaps the most remarkable change was that on the behaviour of the elk; with the wolves hunting those that were out in the open, the prey began to avoid the predator by staying in the forests. All of a sudden, things began to grow in the wide open spaces, and rivers began to flow down different pathways as they were no longer disrupted by grazing hooves.
The wolves, just like the beavers in Britain and the herbivores in the Netherlands and Russia, were keystone species: animals that have a disproportionate effect on the ecosystem. By removing these keystone species we created unhealthy ecosystems that required extensive human management, but through rewilding we were easily able to cure them.
Next time, I’ll discuss all of the issues that rewilding creates, from animal welfare controversies to conflict with farmers. The four examples mentioned here are truly remarkable, but all of these projects have their downsides no matter how ecologically successful they may be!
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