Why are species going extinct?

Why are species going extinct?

Species go extinct because of the process that created them.

Ah ha, not the answer you were expecting. You thought I was going to say habitat loss, pollution, introduced pests, climate change or some other lefty topic sung about by old hippies and youngsters frightened for their future.

Indulge me for a few minutes and follow this little sequence of logic to the end of the post and you’ll see why extinction is more about the process of evolution than it is about humanity.

Polar bears and koala (not) bears

If you go to northern Manitoba, Canada, you can go out to the wilds and see a polar bear. There are even tour operators who will take you and look after you so the bears don’t rip your Gortex jacket.

You cannot see a wild polar bear in Australia.

However, if you go out to the Australian bush, into the right habitat types, keep your eyes keen, and have a bit of luck, you will see a koala. And, yes, a koala is not a bear, it is a marsupial mammal.

There are no wild koalas in Canada.

Canada, polar bears; Australia, koalas. This we know and take for granted. The reason is that all species have regions where they occur in the wild and regions where they do not go and have never been seen, except in a zoo. It’s called their geographic range.

Let’s extend this idea a little.

Bird species in Australia

There are 828 bird species in Australia that are known to be present. Some are rare, others common. Some occur everywhere and some are found in just one or two places or in the case of the King Island scrub tit, on one island. It would take a lifetime of twitching holidays to personally see all these species because it is also nature’s way that species have certain habitats and places they prefer.

Some species are super specialists and only occur in certain very specific habitats, for example, old growth forest. As there is not much of this habitat left, these species have a narrow range. You need to hike into the forest and be very patient in order to see one.

Other species are just about everywhere. The Indian myna or the house sparrow are familiar to half the people on the planet, even those who have never owned a pair of binoculars.

Even in a habitat that occurs everywhere, like open woodland or backyards, not all species occur everywhere. There will be a dozen or so species in the average Aussie backyard in Sydney only several of the species in the Melbourne suburbs will be different, and those in Brisbane different again.

This is normal and always has been. Some species are rare, some are common. Some are localised others are everywhere. Welcome to nature.

In fact, nearly half, 400 or so, of the 828 bird species in Australia occur nowhere else on earth. They are endemic or unique to the island continent or both.

Alright, I’ve laboured this enough.

The point is that this is what the process of evolution does, it creates diversity. Random mutation alongside natural selection results in diversity as organisms focus on the most efficient way to harness resources that they convert into more organisms.

If you prefer to replace organisms in the last sentence with genes, you get Richard Dawkins, Selfish Gene.

I use organisms because a gene does not do it on its own, it needs other genes to make a vehicle that can travel forward in intergenerational time. But, of course, Dawkins is right, really it is genes that are selected.

We are so familiar with the result of natural selection, namely a huge variety of species unevenly spread across regions and habitats, that we take it for granted. Don’t be stupid, everybody knows that there are no wild polar bears in Australia, it’s too hot for them.

Nature is made up of gene combinations that are the most efficient at converting the resources in a given place, given the conditions. This is what evolution does all the time, everywhere.

This is the bit you need to follow… given the conditions.

Specialisation happens as an inevitable result of natural selection. There are still generalists with a fine working model of existence, crocodiles for example, that have not changed much, but the majority of species become quite specialised.

The problem with specialisation is what to do when the conditions change. Just ask the dinosaurs how that went for them.

Again we accept that mass extinction 66 million years ago without blinking. A huge, diverse group of land animals all die out in a short space of time because a meteorite hit the earth and changed the conditions. They couldn’t cope with what the impact and its aftermath did to their food and shelter. It disrupted things too much for them to adapt fast enough. Except for the crocodiles who could switch to fish.

The 5th mass extinction that knocked out the dinosaurs and 76% of species alive at the time, is a dramatic, iconic example of change. Only, the thing is that conditions change all the time. And this means that species go extinct all the time. It is an inevitable part of the process.

I’ll just say this again. If conditions change (and they always do) and they change fast enough, big enough or for long enough, some species cannot survive and go extinct. Period.

This is just a consequence of natural selection creating diversity and the whirlwind of a spinning planet with a complex atmosphere, ocean currents and mobile continents generating change.

The flip side of change that causes extinction is the opportunity for diversity. Change things and gaps open up for new species to exploit. But we’ll save that idea for another time. Today we are on the extinction consequence.

Change and extinction are inevitable

Only this is not what you are told.

Take this example from the front page of the Guardian online feed on 31 March 2019 stating that record numbers of Australian mammals face ‘imminent extinction’ that includes this quote

“The report calls on the next Australian government to commit to a policy that no more of Australia’s unique wildlife species will be allowed to go extinct, and to ensure, backed by the necessary laws and resources, that this policy is fulfilled”

Wilderness Society’s national forest campaigner, Peter Roberston.

Pause and read that quote again.

This person is asking you to believe that extinction, a law of nature that has a history as long and deep as life itself, can be overturned by muppets in Canberra.

Come on, get over yourselves.

You are not that important. Human activity is the biggest current agent of change sure, but to think that a specific political decision can rewrite evolution means you really do not understand the challenge.

We could leave it there as today’s healthy thought. Only there is just…

One more thing

Thinking we can ‘save the koala’ forces us into a bind. We are now imagining that extinction is terrible, an awful result that must be prevented. So important is this premise we even ask the politicians to make a policy to stop it happening.

We would have a very different view of conservation if extinction were an acceptable option because that is what happens in nature.

The choice to save a species from extinction becomes a conscious one made with a clear understanding of cost and benefit. We may still want to save the koala or the panda or the Southern Corroboree frog but if we do it’s a positive choice.

Important postscript

This post simplified natural selection as just about honing a solution to shelter and food and secretly implied that competition for these resources is what sorts out the weaker options. This is true but it’s not the only way.

There is also sexual competition that drives specialisation. Just so you know, Charles Darwin figured this one out too.

Amazing.

Why the sixth mass extinction was inevitable

Why the sixth mass extinction was inevitable

Palaeontologists have a fine time of it. They fossick around in obscure parts of the world where there are few people and take a hammer to rocks.

They have done this for generations, found lots of fossils, and come up with some interesting conclusions.

Here are five of them.

  • 444 million years ago 86% of species were lost.
  • 375 million years ago 75% of species were lost
  • 251 million years ago 96% of species were lost
  • 200 million years ago 80% of species were lost
  • 66 million years ago 76% of species were lost.

These are, of course, the five mass extinction events in the fossil record. The last one being the most famous when all the dinosaurs copped it.

Here is another pattern they found

Over time diversity has increased despite these mass extinctions and several smaller ones in between them.

There are more species alive today than at any other time in evolutionary history, despite the obvious fact that humans are kicking the sixth mass extinction into existence.

This is the history of life on earth. It is dynamic with huge shifts in diversity but with an underlying driver powerful enough to increase diversity over time.

If you believe this evidence then a few core concepts become clear:

  1. Extinction happens.
  2. Large extinction events happen often enough to make another one inevitable.
  3. After extinction events, diversity recovers
  4. And for at least 150 million years the trend is for diversity to increase rapidly, noting that the non-avian dinosaurs were lost during this time.

Diversity happens because there is time enough for mutation and natural selection to hone any number of specialisms. When organisms specialise they are successful in a relatively narrow set of conditions. A proportion of species become vulnerable to change in those conditions.

Enter human beings. Modestly specialised initially but with a distinct advantage. They had the brains and communication to adapt to a wide range of conditions, especially when they tamed fire and then much later discovered fossil fuels.

Once in control of energy humans have appropriated over half the global biomass production, removed vegetation, getting rid of wildlife and altered the composition of the atmosphere. More than enough change for mass extinction.

Humans affected the change but change would have happened at some point. Tectonic plates moving to cut off ocean gyres, volcanic eruptions, another meteorite strike, it would happen soon enough, maybe 50 million years hence.

Is the reality of extinction too painful?

Perhaps it is. Perhaps we are just too much in the present day to accept timeframes beyond ourselves. Certainly, there will be huge consequences of extinction for our production systems, the ecosystem services we rely on, and the very liveability of the planet for our species.

We’ll need a lot of adaptation to survive.

What we might also remember as we plan for change and seek to retain what we can of the diversity of life, that extinction is real and inevitable. It is as much a part of the process of evolution as the creation of new types.

Species

Species

…the fact that ecological communities constantly experience temporal turnover, and that consequently some species will not only fluctuate markedly but also become either locally or globally extinct, is something that, while well appreciated by ecologists generally, is often omitted from popular news stories. 

Mugurran et al 2010

By research paper standards this is an accessible quote. You may only need to read it a couple of times to get the gist. It means what it says.

Everything in nature changes and species disappear from both the backyard and from the planet.

Ask any ecologist who has more than a few minutes of fieldwork on their resume if they agree with this premise and they will say yes. There is change over time. They would concede that if you stare at a patch of nature long enough, it will start to move. Organisms will come and go, sometimes never to return, their place taken by an equivalent.

In my own garden that backs onto eucalyptus forest in the Blue Mountains of NSW I have seen this happen with the seasons as the grass stops growing in winter, during drought when even the trees droop, and also through the decade we have lived in the house.

When we moved in the garden was blessed with tree creepers, fairy wrens and wagtails. There were regular visits by resplendent satin bower birds and even occasionally a lyre bird or two. I have stared at a frogmouth in its daytime roost and had glossy black cockatoos drop casuarina cones on my head. Delightful.

Then, three years ago the noisy miners arrived. An especially aggressive social breeder that with brazen behaviour worthy of a panzer corps will chase all the other species away. Only the big beaked cockatoos and the butcher bird are unmoved.

None of the aforementioned chorus are extinct but they are not longer in my garden.

More recently some new neighbors moved in next door. They have a nervous pointer and a black labrador with a limp. The swamp wallaby no longer hops up from the creek to pick at our herb garden.

There are several important things in this simple everywhere reality of ecological change.

The first is change itself.

Nothing in nature has ever been or ever will be stable. It is not how nature works. At times the dynamic is subtle and hard to see with human perception of time and space. Typically though we can see, smell or hear it. All it takes is a little patience and some observation.

If a human who might live three score years and ten can perceive this change with just a little patient observation, then…

the second important thing is that change is fast.

Incredibly fast on an evolutionary or geological time scale. Happenings that take decades are the blink of an eye equivalent for a planet that is billions of years old.

Such rapidity means that the idyllic lilly pond with the weeping willow tickling the water will not be there in a thousand years or so. Sedimentation and succession will make dryland of it unless there are humans with the spare time to occasionally dig it out.

This is the third important reality, stability requires inputs.

The main reason that nature is so dynamic is due to entropy, more strictly, the constant struggle organisms must undertake to counteract it. It takes an enormous effort to keep things the same. Energy must be pumped in to prevent chaos.

Humans have, of course, become true masters of this use of energy to counter entropy. We have figured out where to find and use external fuel sources to change the world to suit ourselves. It’s our superpower. But it has also duped us into believing that we can keep things the same, despite all the evidence to the contrary. We even think we can save species from local or real extinction.

This is the fourth of the important things, the often crazy notion that we can save species from ourselves, the most severe new driver of ecological change in aeons.

Change as the norm is “omitted from popular news stories” because the acknowledgement not only questions our god-like ability to rule the planet, it would mean admitting our role in the acceleration of change.

After all, the noisy miner spread with the suburb.

Positive future

Scenarios with pragmatic outcomes

It is a short time into the future, nowhere near an aeon. Against all likelihoods, Homo sapiens did not join the hundreds of thousands of species that have crossed the extinction finish line because miraculously there was a meme that spread through the social fabric of every nation on the planet faster than pictures of Harry and Meghan.

The meme said, “ecological communities constantly experience temporal turnover”.

The miracle of course was twofold. People not only understood this gibberish but they extended it to the practicalities of the real world.

Everyone recognised change everywhere and embraced it. They let species move around, leaving some places and moving into others. They saw vegetation as fluid not as a vase on a shelf, still but fragile.They realised that there were some species that would go extinct and that if a particularly cute one was popular enough to save, then this was going to need effort specific to that species. It was a choice.

And they saw the whole landscape, all at once, despite its altered state, and they focused on what that landscape could do, not what was in it.

It was truly remarkable.

It even made the news.

Reputation?

Reputation?

The Australian Broadcasting Corporation, the ABC, holds a reputation. It is a highly respected media source down under, modeled not so loosely on the British Broadcasting Corporation. On taxpayer funds it provides Australians with news, entertainment and community service online, on radio and on TV.

It’s fair dinkum.

No surprise then that the ABC news app uploaded a post providing simple steps people can take to help koalas survive in their area. Just a small but useful morsel of public service information.

Here are the eight headline steps…

  1. Tell people koalas are going extinct
  2. Share social media posts
  3. Protect habitat
  4. Plant koala food trees
  5. Watch out for koalas in trouble
  6. Drive carefully and be vigilant
  7. Contain dogs
  8. Save 24-hour rescue hotline into your mobile

I am not sure what you think about this list.

Have a read of it again.

You may find it helpful and informative just as the ABC online editor no doubt hoped. Perhaps you are a fan of the furry and cute koala, so iconically Australian that stuffed toy versions outsell kangaroos in airport departure lounge shops.

But have you seen one in the wild?

Probably not. So the logic leap is that they are rare and, as the list tells us, going extinct. No doubt they need protection.

But there is a problem.

There is no evidence that koalas are going extinct. We don’t even know exactly how many there are in the wild so it’s impossible to know if the numbers are changing towards an extinction risk.

We do know that this species is widespread, cosmopolitan and does very well in favourable habitat containing younger woody plants. It can do so well that some local populations grow rapidly and become overabundant. We also know that the habitat koalas like exist in both agricultural and natural landscapes from Townsville to Mount Gambier, a latitudinal range of nearly 3,000 km.

We also know that when we have a good way to find them, sniffer dogs ironically, they pop up everywhere, often in places where they were either not known or have not been seen for a long time.

Folks, this critter is no more likely to go extinct than the Pope. There are plenty of places for it to hang on indefinitely.

So number one on the list is a lie.

Items 2, 3 and 4 on the list are, therefore, actions based on a lie. Now we are asked to do things that will cost us time and money because some people believe it’s right even though they present no evidence to justify such a request.

This should sound familiar, we see it in politics every day. Only in that forum we allow ourselves some leeway because we know the buggers are rarely honest, it’s why we invented democracy.

Now for a spoiler alert…

species go extinct

They always have.

An average mammal species is present in the fossil record for about 1 million years. There have been extinctions and mass extinctions throughout evolutionary history, some of them catastrophic, and almost all of them occurred before Homo sapiens even existed. And after each single or mass event, evolution continued to generate even more diversity. It’s what nature does.

So, get over it people. Species are an abstract concept, invented by us to help describe nature and how it works but mainly to satisfy our peculiar need to name and classify objects.

And then, for deep psychological reasons only Freud could begin to fathom, we assign a value to the object. Not the species you understand, the objects that make up the species.

This gives us items 5, 6, and 7 on the ABC’s list.

The objects in this case being specific individual koalas, that you or your canine companion (of a single species but with enough human selected natural variation in form and behaviour for a taxonomists to describe a Family or even an Order) might come across on your travels. Noting, of course, that most people will only see a koala in a zoo because they don’t take long walks in the bush staring up at the canopy.

What these ‘object-centered’ actions do ask is for us to be good citizens. People who are careful, aware of what’s going on around us and should we see distress, offer help. Nothing at all wrong with any of these. It’s just they should be a given. I would want to do this anyway for all objects, including other people, and I would want my kids to be vigilant too. It’s the biblical golden rule from Matthew 7:12 “Do unto others as you would have them do unto you“.

Item 8 on the list is, well, it’s blatant marketing.

A hotline? Come on ABC you are supposed to be the last bastion of the precommercial world where information is the currency, not profit or popularity.

The ‘simple steps’ in this list are just an opinion.

So sorry ABC, not fair dinkum, not fair dinkum at all.

Real numbers

Real numbers

Recently Alloporus lamented in an incredulous post the fake news that is too often a part of the conservation story about the return of an extinct species. An obvious impossibility, but spin it fast enough and the whine turns into a noise you want want to hear.

Well there is a recent counterpoint to this story that talks about the real numbers behind the sorry state of the Earth’s species.

The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) has recently published a major assessment on the health of the world’s species that comes from over 120 cooperating countries. It’s not good folks for pretty much everything is in decline.

The specific numbers can be cherry picked based on your own interest but from elephants to soils everything is falling in quality and quantity as risks rise. The real headline is that these trends are recorded in double digit percentages. We are not talking about a little bit of loss at the margins, this is one in four (25%) or three in five (60%) type effects.

Quotes like

25,821 plant and animal species of 91,523 assessed for the 2017 “Red List” update were classified as “threatened”

means that 28% of the assessed species on the Red List are threatened with extinction, pretty darn close to a third.

And it’s not all about rapid human population growth in the developing world when you see

Soil erosion has affected 25 percent of agricultural land in the European Union

So even where we can apply the technological and supply chain efficiencies of mature economies we are still degrading the place… a lot, a quarter in this example.

Just think now about the Bush stone curlew fake news. It is meaningless in the light of the reality. Even the faint hope it might bring if it were true, the saving of one species is only a brief ‘feel good’ in the bigger picture.

It is time to be rational. We need to fess up to the reality that not only has the horse bolted, but the barn doors are off their hinges.

Fortunately, there is still some habitat to save through smarter resource and land use decisions. Much more habitat and soil to rehabilitate with more sensible land management practices. And maybe even a few species to save.

But the reality is that this has to be done whilst at the same time feeding and raising the living standards of 7.5 billion souls growing at 250,000 a day. Because if this fundamental need is ignored in favour of a conservation ideal, the resources will be taken anyway. It has to be about all values with the humans ones up front.

This is an unpleasant reality but even a limited understanding of human psychology and history tells us that people come first as individuals and then as tribes. It’s what gave us our numerical success and is as unstoppable as the tide. This basic biology has only one outcome.

The real numbers are only going to get worse. This is the truth.

The hope we have is that it should be possible to feed, clothe and house (and put online) all the people currently here (and those about to arrive) whilst still retaining some of the Earth’s innate heritage through smart choices. But there is a big if. Reversing declines and saving some of the best bits will happen, if, and only if, we accept that this is multi-value problem with no one value able to preclude all others.

Crudely this means that production cannot exist without some conservation values and, critically, vice versa. We have to get multiple values from the remaining natural resource base or the real numbers will get an awful lot worse.

Incredulous

Incredulous

Here is a recent headline from an ABC online article, a reputable publicly funded media source

Bush stone-curlews popping up in suburbs as bird once extinct in ACT makes a comeback

Nice you might think given that headlines containing good news are like threatened species themselves, rare and at risk of being lost forever.

Here is the problem.

The IUCN lists the conservation status of the Bush stone-curlew as “least concern”. In other words, its not under any immediate threat of extinction in the wild.

In fact, the species has a broad habitat preference throughout Australia pitching up in open forest, eucalyptus woodland, rainforest edges, grassy plains, arid scrubland and along inland watercourses across much of the vast continent. It is a common species in the cities of Brisbane, Cairns and Townsville and is abundant in the tropical and subtropical north. In other words, it’s not a rare species at all.

I’m told there are pubs up north where you can sup on a stubbie alongside a foraging stone-curlew.

To use the word extinction, the termination of a lineage, where the moment of extinction is generally considered to be the death of the last individual of the species, is a lie.

This bird is not extinct.

Placing a geographic limit so as to use the term is disingenuous. Strippers are extinct in the Vatican is about as crazy a statement.

So is this fake news?

I think it is. The bird species is not actually extinct. It’s not even at risk unless you specify a discrete subset of its natural range. And when we learn that the Canberra specimens were almost certainly taking a wander from a nearby reserve artificially stocked with a few pairs to “reintroduce” them to the local scene, then the implicit hope in the story takes a huge dive.

I know that there are feeds to feed in this modern age of lightning fast news cycles. And I also know that there are good reasons for at least trying to be upbeat when, for the conservation minded, the world appears to be crashing down. But, like cricketers crossing the line, there are consequences for cheating on the truth. In the end people do not respect you, they dismiss everything you say even when you are actually being honest.

So my call to myself, and everyone who is in the business of information, let’s be as honest and as truthful as we possibly can and leave the spin alone when it comes to the facts.

This is easy to say and not at all easy to do but we all have to try.