The death of a rhino symbolizes the catastrophe of the 'sixth extinction'

One dying species

The world bid goodbye to the last male northern white rhino this week. Sudan, the rhinoceros, died in his reserve in Kenya, leaving a daughter and a granddaughter as the only remaining members of their sub-species. With no breeding pairs left, they are, effectively, extinct. Sudan's demise was a a vivid example of what's been called the "sixth extinction." Humans are driving the extinction of species at a rate that can only be compared to what's happened in Earth's past with an asteroid impact or global supervolcano devastated our planet.

Evaluating the damage

Brian Keating is a naturalist and retired head of conservation at the Calgary Zoo and gives wildlife tours through his company, Goingwild.org. He visits Africa at least every year, and has visited the reserve where Sudan lived and died. During his time as a naturalist, he's seen tragic declines in numbers for many species, which could put them on the trajectory to extinction. In Africa, most of the big animals are in trouble. The big cats have seen massive declines, as cheetahs have dropped to only about 7,000 animals, and occupy only ten per cent of their former habitat. As for the lions, Keating says, "Since I've been travelling to Africa, the population of lions has halved, and halved, and halved again," down to 20,000 animals from the 300,000 that existed when he began visiting the continent in 1982.  

But counting individual species are just a small part of the story. It's the overall damage that is really tragic. "It's not species extinction, it's extinction of populations." 

Keating is an avid birdwatcher, who began as a boy. And he mourns the fact that during his life as a birdwatcher, it's estimated that half of the biomass of birds on the planet has disappeared. Similarly, says Keating, globally large animals, the "megafauna," have also declined in biomass — perhaps as much as 60 per cent.

A glimmer of hope

Keating describes himself as an "optimistic pessimist," and suggests there are a few examples where we've been able to pull species back from the brink — that might serve as models for doing better in the future. He points to the famous mountain gorillas of Rwanda and the Uganda, who experts predicted would be extinct by the year 2000. Keating says that thanks to conservation work, there are about 900 mountain gorillas alive today, "which is still a razor blade edge of survival, but it beats the heck out of the three or 400," that were left in the sixties. 

He says it's still possible to preserve the remaining jewels on the planet, "and there are still many of those jewels left." 

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