By: Lykke E. Andersen*

One of my favourite Christmas presents this season was a book recommendation: Inheritors of the Earth: How Nature Is Thriving in an Age of Extinction written by British biologist and ecologist Chris D. Thomas.

As the gift-giver very well knows, I don’t particularly sympathise with ecologists, conservationists, and conservatives, as I find them irrational in their fixation on an imagined perfect world 50 to 150 years ago, which they cling on to at all costs, ignoring billions of years of evolution, and thinking they know better which species (and people) ought to be where and when.

The author of the book, Chris D. Thomas, is labelled “shockingly contrarian” because, in contrast to the popular perception of humans being in the process of causing the 6th mass extinction on this planet, he argues that biodiversity has increased in almost every country, county or island as a direct consequence of human activity.

I have long suspected this was the case, just by watching the beautiful gardens in my parents’ old neighbourhood in a medium sized city in Denmark, and contrasting those with the neighbouring protected forest. The gardens on the street overflowed with thousands of different pretty, pretty plants. The neighbouring forest was also impressive with the large beautiful trees and the deer walking around, but simple biodiversity bean-counting would indicate that the city gardens were clearly more biodiverse.

Thomas, as a Cambridge trained biologist with a masters in ecology and a subsequent Ph.D. from University of Texas, having published hundreds of scientific studies, which have been cited more than 37,000 times, obviously packs a lot more credibility than my intuition. He estimates that, on average, every island (and island-like area) has 20-100% more biodiversity now than it would have had in the absence of humans.

Needless to say, he recognizes the devastating effects humans have had on big animals and vulnerable species (such as flightless birds) across the world, but he argues that these extinctions were mainly caused by our stone-age ancestors (deliberately hunting large animals) and early explorers (inadvertently bringing along dogs, rats and other species that rapidly extinguished local species unaccustomed to those threats). Modern society is causing an unprecedented increase in biodiversity, mainly because we are moving species across continents so much more rapidly than plate tectonics and the occasional hurricane have ever been able to do before.

Ecologists usually hate imported species, and they have mobilized customs officials in almost every airport of the world to fight against the movement of species across borders. Fortunately, they are not very effective. I personally smuggled three Danish acorns into Bolivia 18 years ago, and while the resulting trees are still debating between themselves whether it is summer or winter (1), they are finally turning into real oak-trees. So I have personally increased biodiversity in the Bolivian Altiplano, while I am pretty sure I haven’t caused any extinctions.

And that is the general effect of humans on Earth. We are causing biodiversity increases much more rapidly than we are causing extinctions. Thomas’ arguments go much further than just moving species around, though. He argues that the species transported to new places will eventually evolve into different species, unable to mate with their ancestors. Thus, my oak-trees in Bolivia, if they grow old enough to have acorns, may have off-springs that turn into ever-green oak-trees, much different from their grand-parents. If that really happens, I would personally have caused a new species to appear!

I absolutely love botanical gardens around the world. It is one of the first places I go to when I visit a new city. I admire the incredible, visionary work of their founders, and I refuse to consider it a crime to help increase biodiversity and natural beauty in the world, so I will continue to smuggle in the seeds of beautiful/tasty/useful plants I come across.

Thomas tells the story of the Monterey Pine, an endangered species (according to the International Union for the Conservation of Nature), and critically endangered in one of its original locations on Guadalupe Island, mainly because of feral goats and a fungal disease. Fortunately, someone smuggled seeds of the Monterey Pine to New Zealand, Australia and Chile, where the pine has spread happily in the absence of those threats, and with the help of humans. Indeed, by now it is the most widely planted pine in the world, valued for rapid growth and desirable lumber qualities. It currently accounts for 95% of timber production in Chile, and 89% of New Zealand’s plantation forests (2).

Of course conservationists complain that the Monterey Pine (Pinus Radiata) is displacing native species in these new locations. Meanwhile, on Guadalupe Island conservationists are killing off the goats and fencing in the few remaining critically endangered pine trees to try to keep them alive. This just does not make any sense to me. How can the very same plant be a critically endangered species in one location, in need of preservation at all costs (even justifying the killing of other species), while it is considered an invasive species in other locations, despite being highly valued by the local population?

If we want our own and other species to survive in this era of rapid change, we really have to get over our neophobia and our tendency to judge which species (and persons) ought to be where and when. Every species should be allowed to grow in the environment where it best flourishes (3). That is how our planet has always dealt with an ever-changing climate and thus managed to systematically increase the level of biodiversity.

I encourage everybody to engage in a bit of civil disobedience and help disseminate their favourite species to other parts of the globe, and thus help avoid the 6th mass extinction.


* Senior Researcher at INESAD. The viewpoints expressed in this blog are the responsibility of the author and may not reflect the viewpoints of all members of Fundación INESAD.


(1) I can’t blame them, because it is freezing cold right now in the middle of summer and with much less sun than in the middle of winter. I am impressed they are surviving at all.


(3) With the exception of diseases and pests that clearly harm humans. Those we are allowed to fight in any way we can in the name of self-defence.


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