Extinction risk

I’D like to reply to your Counterpoint article of June 8.

The earth took more than 10 million years to recover from the mass extinctions of the Cretaceous. It needed these species because every species has a niche role that helps the host ecosystem to function productively and efficiently.

The key word here is ‘balance’.

Remove the apex predator, for example the wolf, and the cariboo eat out the aspen trees that provide the logs for beavers to build their dams.

Lacking resources to build their dams and lodges, the beavers disappear; the dams fail and the fish and wildlife that depend on the lagoons behind the dams also disappear. Now that the wolves have been reintroduced to Yellowstone National Park the aspens are growing again and the beavers are back.

We might also consider the effects of removing our apex predator, the dingo.

As for extinction, this is the mechanism for adapting to changes to the Earth over long periods.

As continental drift moved the continents around, climates change.

Australia changed from a forested continent to a mainly desert one, species disappeared and new better-adapted species replaced them.

In fact, 99.9999% of all the species that have ever lived on earth since life began nearly four billion years ago are extinct.

This shows how important extinction is.

It also puts us in the frame and tells us that unless we take our relationship with the animals and plants we share the Earth with a lot more seriously, we could be next!

As the example of the wolf and the caribou demonstrates, the issue is controlling populations so that a working balance is maintained. In 1950, when I was eight years old there were about three billion people on earth.

Each of them had an average ecological footprint of 8.5ha.

In 2020 there were about eight billion people on earth. Each of them had an average ecological footprint of 11ha.

Such a footprint means that collectively we required 1.7 times the surface area of the earth to support us. Need I say more?

Rob Tanner, Bridgewater