How many species do we need?

The way that we are managing this planet has led to many species of life now being at risk of extinction. Of the “highest” form of life, mammals, fully one fifth (21%) of species are now at risk of extinction.

If we carry on as we are then that figure will continue to rise, year on year, year after year, and one day we will find the species call “humans” is on it.

But before we look at why this matters for business, let’s look at why it matters for nature. Does it matter if we lose 20% of species, if we still have 80% remaining? Or even 50%? How many species do we really need?

You may intuitively feel that a “thriving rainforest”, “teeming with life”  is somehow better than a “barren desert”. Or you may not. But can it be measured objectively?

A group of scientists set out to answer this question and built a facility called the “Ecotron”*. They used it to study what happens when there are more, or fewer, species.

What they found was interesting.

  • First, the more species there are, the more efficiently those organisms harness energy from sunlight. If there are more species then the system as a whole consumes more carbon dioxide, turning it into plant tissue which other species can eat. The more species there are, the more productive the system as a whole is.
  • The second thing the researchers found was that when part of the system changed significantly (for example, if there was a drought) then the systems with more species were impacted less than the ones with fewer species, and they recovered more quickly as well.

A richer, more varied eco-system is able to be both more resilient and more productive than a less varied one. The same applies for the economy.

What this also means is that the species on this planet are like the rivets holding the wings on to the body of an aeroplane. We can lose a few species, or a few rivets, and the wings will still stay on. But beyond a certain point, the loss of any single species could cause the wings to drop off.

The species are the environment. Our ‘plane’ (or perhaps our plane-t?) is held together by each of these individual species. Lose any one and we lose a part of the ‘plane’ we are flying in.

* For more details on the Ecotron see this book and also the New Scientist:

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