The last blog entry I posted mentioned the reintroduction of red kites to England, surely one of this country’s most impressive conservation success stories of the past few decades. Such reintroductions can be seen as one minor aspect of the “rewilding” programme being advocated by some conservation biologists. In its most extreme form, radical rewilders advocate populating whole landscapes with large herbivores and predators that once roamed these regions but are now locally extinct, either because of human hunting pressure or environmental change (sort of Jurassic Park backed up with real science). The idea is that reintroducing such animals results in more “natural” habitats in which ecological processes are returned to a more pristine state and biodiversity is maximised.
There are arguments for and against rewilding in all its forms, and four recent coincidental occurrences make rewilding a topical subject for this blog.
Coincidence one is that the Guardian newspaper has posted a great animated video about rewilding, voiced by environmental writer George Monbiot, whose work I’ve mentioned previously. It’s an interesting overview of rewilding, if a bit simplistic; and (spoiler alert!) I’m sure I’d not want to jump naked into a river with hippos!
Coincidence two is that I’m currently reading Once and Future Giants: What Ice Age Extinctions Tell Us About the Fate of Earth’s Largest Animals by Sharon Levy, which discusses some of the more radical rewilding notions that have been proposed, such as introducing elephants, lions, zebra and other African megafauna to North America, as stand-ins for their Pleistocene cousins which may (or may not) have been over hunted by the ancestors of native Americans. That’s a controversial topic, as you might imagine, and it’s a book that’s well worth reading, not least because it effectively captures the atmosphere of the various camps of scientists promoting the hypotheses they personally support.
Coincidence three is that a paper was published in the journal Science last week which provides evidence for what can happen when larger animals (often the first to go locally extinct) are removed from ecological communities. In this case, the seeds of a dominant, bird dispersed palm tree have evolved to be significantly smaller in size in those populations where the largest seed dispersing birds have been removed. All of this has happened in the last 1o0 years or so, remarkably rapid evolution. One of the authors, Spanish scientist Pedro Jordano, gives an account of the paper in his blog. The study is one of the few published that links loss of biodiversity of species interactions to their ecological and evolutionary consequences, and has generated a lot of media attention.
The final coincidence is that a short review paper has finally appeared which I co-authored with Duke University medical researcher William Parker entitled “Evolutionary biology and anthropology suggest biome reconstitution as a necessary approach toward dealing with immune disorders“. You can take a look at the paper (or at least read the abstract) yourself. But in essence the review places William’s Biome Depletion Theory in a broader perspective of how the loss of species with which Homo sapiens would normally interact (in this case gut worms of various types) can have profund knock-on effects for human health and may explain the epidemics of some conditions that are currently prevalent within industrialised societies. More controversially, the review advocates that we begin to routinely rewild our gut fauna by selectively introducing one or more types of laboratory-bred worms to the guts of children. There’s already a lot of discussion around this topic but one day in the future such procedures may become no more unusual than standard childhood vaccinations.
Having said that, there were enough problems convincing land owners that reintroducing beavers was a good thing in the Scottish Highlands, whilst similar plans for wolves and bears have stalled; reintroduction of tape worms to their children’s lowlands will probably take even more convincing.