Why are species going extinct?

Posted on 31 May, 2019 by alloporus

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.

Eat your greens while you can

Posted on 24 May, 2019 by alloporus

Many key components of biodiversity for food and agriculture at genetic, species and ecosystem levels are in decline. The proportion of livestock breeds at risk of extinction is increasing. Overall, the diversity of crops present in farmers’ fields has declined and threats to crop diversity are increasing.
FAO Commission on Genetic Resources for Food and Agriculture

This banal quote comes from the web summary of a critical FAO Report on The State of the World’s Biodiversity for Food and Agriculture.

It is bad people.

Biodiversity loss is not just about Andean condors, orangutans, koalas and rhinos, as important as these iconic creatures are, it is also about a myriad of plants, microbes and invertebrate animals, and especially insects, that actually make nature what it is and, crucially, allow nature to provide for us.

Alloporus has banged on about this for ages. Blue in the face kind of stuff. Here are a few:

They have bored faithful readers witless. And the message still holds.

Biodiversity loss is bad for humans.

This recent message from the FAO is a little more subtle. It refers to the loss of biodiversity in the diversity that humans have created over generations of artificial selection. This is the diversity we get from humans playing god. Think chihuahuas and great Danes, sausage dogs and schnauzers. Only it also applies to crops and livestock.

We made it and now we are getting rid of it.

Let’s back up a little and ask why we made genetic, species and ecosystem diversity in agricultural systems in the first place.

Well right from the beginning of agriculture 10,000 years ago it was clear that wild varieties of grass were never going to deliver enough grain and wild cattle were way too unruly for the herd boys to cope. Better options were needed.

Initially through trial and error and later through the wonders of more formal selective breeding, farmers were able to choose crops and varieties that were best suited to the specific conditions on their farm and run livestock that would breed well and grow fat without squishing the shepherd.

It did not matter if that was in the highlands of Scotland or southern Sudan, there were suitable beasts and ideal crops.

This was humans creating variety for their own ends. Selecting the best production system possible. And for a few thousand years this meant the creation of all sorts of efficient breeds and crop types that became familiar to local communities. It helped to create distinctive cuisines and trade in the items that couldn’t be grown locally, spices being the most famous example.

Then two inventions changed everything.

The first was mechanised agriculture.

This meant ploughs that would never tire and fertilizers that made it possible to grow crops that unimproved soil could not support. Ubiquitous energy also meant we could synthesize and deliver pesticides and herbicides whenever they were needed.

The second was that we figured out genetics and how to use this to rapidly select for optimal varieties that could use the tilled soil and fertilizer to deliver the best possible yields.

It was possible to make serious money from agriculture if you could harness these breakthroughs and scale them up. So we did. We tilled the fields and spread fertilisers, then planted fewer and fewer types of crop. The ones that gave the best yields and market prices: corn, wheat, rice and potatoes.

This production we converted into more people.

Agriculture created diversity to ensure food production was possible almost everywhere. Fossil fuel energy homogenised production for high yield crops on the best soils in the most benign climates and squeezed the market.

No problem surely. What is the FAO going on about? We have more food than ever and in most places, it is as cheap as chips.

Well, what happens if the handful of species that make up the bulk of production are hit with a disease or what if the climate changes in the main grain growing regions?

If the production system is diverse then it can adapt to these events shifting readily between crops not affected by plague or drought. If the system is simple, it is far less resilient to change.

More importantly, if these crops and varieties from ancient genetic stock are lost, there is nothing for the geneticists to latch on to and engineer their way out of a production crisis.

This brings us back to biodiversity proper. It is the resilience of diverse systems that is most valuable to humanity, not the presence or not of iconic species. We have to have as much genetic, species and ecosystem diversity as possible if only as a reserve for future options should things go sour.

There is great irony in the FAO report.

Humans first create and then destroy diversity. That is a hoot.

That we are doing it as blindly as we eradicate what nature created makes you want to cry.

Why the sixth mass extinction was inevitable

Posted on 17 May, 2019 by alloporus

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:

Extinction happens.
Large extinction events happen often enough to make another one inevitable.
After extinction events, diversity recovers
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.

Should there be drought relief payments?

Posted on 10 May, 2019 by alloporus

When it’s been dry for months, the last two crops have failed, and it’s still 40 degrees in the shade, you’d have to be a sociopath not to have empathy for the farmer.

No matter how courageous and resilient farmers might be, there are limits to what any human being can handle, physically, financially and emotionally. And drought is tough, really tough.

Even the most closeted city dweller should feel something and want to help. Donate maybe. Perhaps lobby for governments to assist in what is an obvious emergency. And that is what has happened in the current drought in NSW.

Public donations have come from all around the country and state and federal government have allocated drought relief funding because, more often than not, the human response to a crisis is to help.

Emergency assistance when drought is at its worst helps to alleviate the worst of this for those most affected. It is a natural and proper response. What is known about the effects of drought on rural communities is that not everyone is affected the same way, some really struggle and others ride it out.

Some farmers suffer acute or prolonged hardship. Other survive, some relatively unscathed. Typically the survivors have prepared their stock, kept fodder on their paddocks by resting them, closed down their crop production early and planted a cover crop, or have cash in hand from a financial plan that anticipated lean times. Some or all of these tactics make it possible to sit out dry times. These landholders are also in great shape to benefit when the drought breaks as it always does.

The thing is it was the same in the previous drought and will be the same in the next one. And there will be a next one. Some farmers need emergency help and others do not.

But Jacki Schirmer and her colleagues suggest that multiple inquiries and research studies have concluded that this approach is not enough and we need to support farmers in good times as well as bad. Perhaps get a little ahead of the emergency and promote some of the actions that the survivors knew about.

When water supplies dwindle we panic and forget about it when it’s been raining. The Australian federal government did the same with energy supply. Forget about it until the lights go out.

This is poor planning and terrible leadership.

There is great irony in a Minister handing out drought relief and making it a photo op for his leadership. If he was a true leader he would ask if there was anything that could be done about a drought in advance of it happening. For example, is there insurance that can reduce some of the pain? There is a solution for most farmers and, although this is a contentious suggestion, most farms can be drought-proofed to some degree. However, it requires planning, a long game and as Schirmer et al, support in the good times.

What should drought relief look like?

If the idea is not to need the emergency response, then ‘relief’ should happen before the drought, embedded in the production system.

This would include actions that are

more conservative to production
that promote retention of soil moisture (most actions that retain ground cover and reduce tillage),
that encourage soil carbon (because this helps retain soil moisture)
keep water on the farm by slowing down water movements (as Peter Andrews advocates)
production system change

Suppose you take the drought relief money, several billion at the last count, and use it as incentive payments to undertake actions that are consistent with this list.

It might just help.

Alternatively, incentivise commodity prices from drought-resistant production systems

Perhaps force landholders to pay back drought relief payments during the years of plenty.

Whatever the carrot or stick policy approach you’d prefer, they can all result in fewer landholders in strife.

So the answer culd be no, we shouldn’t have drought relief payments. Perhaps drought mitigation payments and restructuringturing instead.

How to interpret a percentage change

Posted on 3 May, 2019 by alloporus

Here is what the International Energy Authority said happened to carbon emissions last year across the globe.

Carbon emissions rose by 1.7 per cent in 2018 to a record 33.1 billion tonnes, with coal making up a third of the total increase

That is 560 million tCO2 more carbon emitted than the previous year.

That increase is equivalent to the total emissions of the international aviation industry or if you prefer, the annual emissions for Australia.

Recall that 1990 was a pivotal year for climate change issues. It was chosen, arbitrarily for those not in the know and all those with an ounce of common sense, as the benchmark year to compare targets for emission reduction.

In 1990 global greenhouse gas emissions were roughly 22.4 billion tCO2.

Rather than concern ourselves with the increase since then, yep it is half as much again, let’s focus on what a 1.7 per cent increase on 22.4 billion looks like.

It’s 381 million tCO2e

Buckets of water example

Now, let’s suppose that I have two buckets the size of laundry baskets. Each bucket is big enough to hold 50 litres of water.

The first bucket is the 1990 bucket. It contains 22.4 litres of water.

The second is the 2018 bucket and it contains 33.1 litres of water.

If each day I added 1.7% of the starting volume to each bucket (381 ml and 560 ml) in 72 days the 1990 bucket would be full.

The 2018 bucket is spilling water on the floor in 30 days.

Less than half the time!

Same percentage. Very different result.

The analogy is not quite reliable for the greenhouse gas issue. The atmosphere may be like a bucket in that it has a finite volume but it is a huge bucket unlikely to overflow with gas.

The issue for greenhouse gases is, of course, the way they alter the atmospheric composition and change the warming potential, retaining more of the sun’s energy as the proportion of greenhouse gases rises.

The per cent change result still holds. 1.7 per cent of the 2018 amount has a much bigger effect than 1.7 per cent of the 1990 amount.

Global population example

The global population growth rate in 2018 is around 1.1% or roughly 83 million people added to the mix each year.

This percentage gain is less than the 1.6% gain in 1990 that delivered roughly the same number of new people.

So again let’s do the bucket test. This time we’ll go with the 1.1 per cent gain and use slightly smaller, 10-litre buckets.

The 1990 bucket starts with 5.3 litres of water and the 2018 bucket has 7.2 litres.

If each day I added 1.1% of the starting volume to each bucket (58 ml and 79 ml) in 81 days the 1990 bucket would be full.

The 2018 bucket is spilling water on the floor in 35 days.

Lower percentage but a faster fill. Ouch.

Pay rise example

Is it fair to give a 1% pay rise to all employees in the company? Sounds fair.

Everyone gets the same proportional raise, all the boats get to float. Except that the CEOs 1% gets him a new fridge out of the first paycheck and the tea lady gets a coffee at Starbucks.

Be aware of percentages when the media spout them.

They are only useful if you know the amount the percentage refers to.