Playing Hide and Seek or Hidden Forever?

So apparently the Thylacine is back.

There have been recent sightings of a Thylacine, or Tasmanian Tiger, on mainland Australia. Last seen as a single animal in captivity, the Thylacine has been considered extinct since 1936.

Officially classified in Australia as ‘extinct’, sightings in both Tasmania and occasionally in mainland Australia have kept life in the Thylacine species.

‘Benjamin’ – The last Tasmanian Tiger, via Wikimedia Commons

After hearing the news, a few questions popped out at me:

  1. When is a species or ecosystem officially extinct?
  2. How do scientists track presumed extinct species?
  3. When do we (either as scientists or the public) give up on a species?

When is a species officially extinct?

Unsurprisingly, evidence of thought-to-be extinct animals is hard to come by.

You can imagine the difficulty of a research organisation trying to justify the research of a rare species.

Find one and make headlines across academic and social medias. Fail and the work may be classified a waste of time and money.

But conservationists should keep an eye and ear out. If nothing else, not finding a species is another data collection point towards confirming extinction.

And you never know when one may ‘rise from the dead’. So-called Lazarus species have been found after declared extinct.

A local Lazarus species is the Leadbeater’s Possum. Thought extinct after the Black Friday bushfires in 1939, they were rediscovered in 1961.

The organisation behind conservation statuses is the International Union for the Conservation of Nature (IUCN). The IUCN consolidates research from around the world to create estimated health, vulnerability and population for species and habitats.

The IUCN lists a species as extinct only when “there is no reasonable doubt that the last individual has survived”. Unfortunately, the global extinction rate is estimated to be at least 10,000 species per year.

According to the IUCN Red List of Threatened Species, the Thylacine is gone forever.

How are species tracked?

It’s incredibly difficult to be certain that a species no longer survives.

The world is a massive place. With 95 percent of the world’s oceans unmapped, and around with 18,000 new species discovered in 2016, it is getting harder and harder to find ‘lost’ species.

Images, audio visual recordings and DNA are all vital tools in the kit of people trying to track hard to find species.

As you can see from the Thylacine images, blurriness is often the hallmark of amateur camerawork.

Sighting of the Thylacine (Source: Andrew Mooney Supplied to the ABC)

The most reliable way of verifying the existence of a species is through DNA analysis. Hair and blood samples can be collected from nests and burrows, and DNA is often present in faecal matter.

 

All these listed methods are suitable for faunal species. Although flora rarely move, they require researchers looking in exactly the right spot.

For instance, the ‘living fossil’ Woollemi pine was discovered in 1994, despite growing 150km from Sydney.

When do we give up?

Ideally, never. Conservation of existing species and habitats is the logical cure for extinction.

Conservation efforts are restricted by funding. The unfortunate truth is funding is frequently based on cost-effectiveness, or achievable outcomes.

It’s difficult to know the precise role a species plays within the broader ecosystem, and unfortunately those functions are often discovered in hindsight.

One of the most interesting stories of unintended ecosystem consequences is the removal of wolves into Yellowstone National Park (read for yourself here).

As a final step, there have been discussions around cloning from preserved genetic material.

As much as it might be interesting to see the Thylacine roaming the country again, if we can’t comprehend the function of a living species in an existing ecosystem, then it might be a step too far to introduce something from a bygone era.

That being said, I know I cried at the extinction of the reintroduced Australian dinosaurs

The fabled Australian Palmer-saurus (Source: Sunshine Coast Daily