WWF report: Global wildlife populations down by half since 1970

[Hamilcar]

It would really help if we collected the useless third of humanity and put them on a giant "Ark" ship and send them to Mars, with assurances that we'll join them eventually.

[CountDeMoney]

It's Halloween season, so let's have an update to this horror story.

Nobody cares, man.

[grumbler]

It would really help if we collected the useless third of humanity and put them on a giant "Ark" ship and send them to Mars, with assurances that we'll join them eventually.

Ah, someone else who's read "the Marching Morons." 

[Syt]

It would really help if we collected the useless third of humanity and put them on a giant "Ark" ship and send them to Mars, with assurances that we'll join them eventually.

Ah, someone else who's read "the Marching Morons." 

More likely a reference to the Golgafrinchan Ark in Hitchhiker's Guide ot the Galaxy: http://hitchhikers.wikia.com/wiki/Golgafrinchan_Ark_Fleet_Ship_B

Though it might be that Adams got his inspiration from Marching Morons.

[Syt]

It's Halloween season, so let's have an update to this horror story.

https://www.nationalgeographic.com/animals/2018/10/millions-of-years-mammal-evolution-lost-news/?user.testname=none

Human-caused extinctions have set mammals back millions of years

Mammals took over the world after the last big extinction event. Now, one mammal is undoing all of that—us.

IT'S OFTEN SAID that extinction is the rule, rather than the exception—after all, 99.9 percent of all species that have ever existed on Earth have gone extinct. In a sense, that adage is true. Life on this planet has toughed it out through five mass extinction events, in which huge numbers of species disappeared during relatively short periods of time. After each, life eventually rebounded.

The keyword in that last sentence is eventually, though. Many scientists say we're in the midst of a sixth mass extinction, with species dying off 100 times faster than they have in the past. And, according to a new study, it'll take several million years for mammals to bounce back from the extinctions that have been occurring because of us.

The scale of the losses

"No matter how you look at it, it is going to take a long time for mammals to recover," explains Matt Davis, a paleontologist with Aarhus University's Centre for Biodiversity in A Changing World (BIOCHANGE) in Denmark and lead author on the paper published this week in Proceedings of the National Academy of Sciences.

Davis, with the help of ecologists Søren Faurby and Jens-Christian Svenning, using funding from the Carlsberg Foundation, set out to determine just how much evolutionary history has been lost in the mammal lineage alone since the rise of modern humans after the last ice age (roughly, in the past 130,000 years). In addition to counting the number of mammal species that have gone extinct (about 300, in case you were curious), they determined how evolutionarily distinct each species is—that is, the amount of time it spent evolving independently, or in other words, its phylogenetic diversity.

If you think of life like a tree, then this evolutionary uniqueness is akin to the length of the branch for each species or group of species. The longer the branch, the more the species have changed since splitting of from their shared ancestors. According to the team's models, in the past couple hundred thousand years, we've lost about two and a half billion years of evolutionary history.

"With the extinction of so many megafauna, we've lost both a whole chunk of functional space and some of the longest branches on the evolutionary tree," Davis explains. "This kind of pattern isn't common in the extinctions we know of from the fossil record, so we are entering uncharted territory."

The authors calculated that given the current rate of extinctions, we'll lose even more mammals in the next 50 years, and it'll take 3 to 5 million years to once again reach today's biodiversity levels. If we want to go back to the level of mammal diversity that existed before our species, that'll take 5 to 7 million years. Plus, since big body sizes develop more slowly than small ones, it will take even longer to recover the loss of diversity in large mammals like mammoths that occurred between 2,000 and 50,000 years ago. And those are the "best case scenarios," Svenning says.

Weighing what matters

"Any study like this is always something of a 'back of the envelope' study because there are so many moving parts, but the authors pulled it all together wonderfully," says evolutionary ecologist Will Pearse from Utah State University, who was not associated with the research. The findings aren't all that surprising to him, but he's still upset by them and says he "shuddered" when he read the part about how long recovery could take. "This study shows we're on the brink of losing so much diversity it may not even recover within the lifetime of our own species," he says. "And if that isn't cause for concern, I don't know what is."

Evolutionary biologist Arne Mooers from Simon Fraser University in Canada, too, found the paper unsurprising but sobering, and wonders how the findings will inform conservation policy going forward. "That is the 20,000-dollar question, because it gets to the heart of what conservation biologists are actually trying to conserve," Mooers says.

Still, it's unclear how to bridge the divide between research and conservation policy. "So far, phylogenetic diversity has mostly been an academic issue and hasn't been used much with conservationists on the ground," Davis explains, and he feels that should change. "Phylogenetic diversity isn't the only metric we should be using, but it is one we should be using a lot more."

Still, there's only so much time and money to go around, so studies like this inevitably raise questions about how those resources should be allocated says Christopher Lean, a philosopher of science at Australian National University who was not a part of the research team. He says the paper is "critical" for conservation science, as it highlights the importance of preserving evolutionary diversity.

"We are currently losing lineages with unique evolutionary history at a devastating rate," he says. "When we lose distinct species we lose evolutionary heritage and unique possibilities held within this heritage."

Pearse says he doesn't see these findings as changing how conservation is conducted so much as underscoring the urgency and magnitude of the task. "For me, the saddest part of this is all the history we are losing," he says. "When we kill off a species, we are depriving our children of millions of years of unique, unbroken history."

We're much less flippant about the protection of ancient human artifacts, he points out. "Stonehenge is about 5,000 years old, and so we would never destroy that, but 5,000 years barely registers in comparison with the shortest twigs on the mammalian tree of life that we are so willing to snap off."

[HVC]

That's not fair. Mammals we eat are doing great too. Come on nature, make yourself tastier, it's your only hope.

[Eddie Teach]

Mammals the Chinese eat, not so much.

[dps]

Mammals the Chinese eat, not so much.

Dogs and cats are doing fine.

[Eddie Teach]

I was speaking of rhinos and tigers.

[dps]

I was being facetious.

[Syt]

Long article on NYT about the massive drop in insect populations in the past few decades and the influence on other populations, and also how little we actually know about insect populations: https://www.nytimes.com/2018/11/27/magazine/insect-apocalypse.html

Some excerpts:

When his parents took him driving, he remembered, the car's windshield was frequently so smeared with insect carcasses that you almost couldn't see through it. But all that seemed distant now. He couldn't recall the last time he needed to wash bugs from his windshield; he even wondered, vaguely, whether car manufacturers had invented some fancy new coating to keep off insects.

In the United States, scientists recently found the population of monarch butterflies fell by 90 percent in the last 20 years, a loss of 900 million individuals; the rusty-patched bumblebee, which once lived in 28 states, dropped by 87 percent over the same period. With other, less-studied insect species, one butterfly researcher told me, "all we can do is wave our arms and say, 'It's not here anymore!' "

Anyone who has returned to a childhood haunt to find that everything somehow got smaller knows that humans are not great at remembering the past accurately. This is especially true when it comes to changes to the natural world. It is impossible to maintain a fixed perspective, as Heraclitus observed 2,500 years ago: It is not the same river, but we are also not the same people.

A 1995 study, by Peter H. Kahn and Batya Friedman, of the way some children in Houston experienced pollution summed up our blindness this way: "With each generation, the amount of environmental degradation increases, but each generation takes that amount as the norm." In decades of photos of fishermen holding up their catch in the Florida Keys, the marine biologist Loren McClenachan found a perfect illustration of this phenomenon, which is often called "shifting baseline syndrome." The fish got smaller and smaller, to the point where the prize catches were dwarfed by fish that in years past were piled up and ignored. But the smiles on the fishermen's faces stayed the same size. The world never feels fallen, because we grow accustomed to the fall.

People who studied fish found that the fish had fewer mayflies to eat. Ornithologists kept finding that birds that rely on insects for food were in trouble: eight in 10 partridges gone from French farmlands; 50 and 80 percent drops, respectively, for nightingales and turtledoves. Half of all farmland birds in Europe disappeared in just three decades.

The study included data from the 1970s and from the early 2010s, when a tropical ecologist named Brad Lister returned to the rain forest [on Puerto Rico] where he had studied lizards — and, crucially, their prey — 40 years earlier. Lister set out sticky traps and swept nets across foliage in the same places he had in the 1970s, but this time he and his co-author, Andres Garcia, caught much, much less: 10 to 60 times less arthropod biomass than before. (It's easy to read that number as 60 percent less, but it's sixtyfold less: Where once he caught 473 milligrams of bugs, Lister was now catching just eight milligrams.) "It was, you know, devastating," Lister told me. But even scarier were the ways the losses were already moving through the ecosystem, with serious declines in the numbers of lizards, birds and frogs. The paper reported "a bottom-up trophic cascade and consequent collapse of the forest food web."

[Razgovory]

Cool.  There hasn't been a mass extinction of insects since the Permian-Triassic.  Actually that was the only mass extinction of insects.

[jimmy olsen]

Cool.  There hasn't been a mass extinction of insects since the Permian-Triassic.  Actually that was the only mass extinction of insects.

Yeah...that's really a bad fucking sign.

[Syt]

More on the insect decline:

https://www.bbc.com/news/science-environment-47198576

Global insect decline may see 'plague of pests'

A scientific review of insect numbers suggests that 40% of species are undergoing "dramatic rates of decline" around the world.

The study says that bees, ants and beetles are disappearing eight times faster than mammals, birds or reptiles.

But researchers say that some species, such as houseflies and cockroaches, are likely to boom.

The general insect decline is being caused by intensive agriculture, pesticides and climate change.

to many other species, including humans.

They provide food for birds, bats and small mammals; they pollinate around 75% of the crops in the world; they replenish soils and keep pest numbers in check.

Many other studies in recent years have shown that individual species of insects, such as bees, have suffered huge declines, particularly in developed economies.

But this new paper takes a broader look.

Published in the journal Biological Conservation, it reviews 73 existing studies from around the world published over the past13 years.

The researchers found that declines in almost all regions may lead to the extinction of 40% of insects over the next few decades. One-third of insect species are classed as Endangered.

"The main factor is the loss of habitat, due to agricultural practices, urbanisation and deforestation," lead author Dr Francisco Sánchez-Bayo, from the University of Sydney, told BBC News.

"Second is the increasing use of fertilisers and pesticides in agriculture worldwide and contamination with chemical pollutants of all kinds. Thirdly, we have biological factors, such as invasive species and pathogens; and fourthly, we have climate change, particularly in tropical areas where it is known to have a big impact."

Some of the highlights of study include the recent, rapid decline of flying insects in Germany, and the massive drop in numbers in tropical forests in Puerto Rico, linked to rising global temperatures.

Other experts say the findings are "gravely sobering".

"It's not just about bees, or even about pollination and feeding ourselves - the declines also include dung beetles that recycle waste and insects like dragonflies that start life in rivers and ponds," said Matt Shardlow from UK campaigners Buglife.

"It is becoming increasingly obvious our planet's ecology is breaking and there is a need for an intense and global effort to halt and reverse these dreadful trends. Allowing the slow eradication of insect life to continue is not a rational option."

The authors are concerned about the impact of insect decline up along the food chain. With many species of birds, reptiles and fish depending on insects as their main food source, it's likely that these species may also be wiped out as a result.

While some of our most important insect species are in retreat, the review also finds that a small number of species are likely to be able to adapt to changing conditions and do well.

"Fast-breeding pest insects will probably thrive because of the warmer conditions, because many of their natural enemies, which breed more slowly, will disappear, " said Prof Dave Goulson from the University of Sussex who was not involved in the review.

"It's quite plausible that we might end up with plagues of small numbers of pest insects, but we will lose all the wonderful ones that we want, like bees and hoverflies and butterflies and dung beetles that do a great job of disposing of animal waste."

Prof Goulson said that some tough, adaptable, generalist species - like houseflies and cockroaches - seem to be able to live comfortably in a human-made environment and have evolved resistance to pesticides.

He added that while the overall message was alarming, there were things that people could do, such as making their gardens more insect friendly, not using pesticides and buying organic food.

More research is also badly needed as 99% of the evidence for insect decline comes from Europe and North America with almost nothing from Africa or South America.

Ultimately, if huge numbers of insects disappear, they will be replaced but it will take a long, long time.

"If you look at what happened in the major extinctions of the past, they spawned massive adaptive radiations where the few species that made it through adapted and occupied all the available niches and evolved into new species," Prof Goulson told BBC News.

"So give it a million years and I've no doubt there will be a whole diversity of new creatures that will have popped up to replace the ones wiped out in the 20th and 21st centuries.

"Not much consolation for our children, I'm afraid."

Original paper: https://www.sciencedirect.com/science/article/abs/pii/S0006320718313636

[mongers]

.....
snip.

Original paper: https://www.sciencedirect.com/science/article/abs/pii/S0006320718313636

Thanks for that Syt, an interesting and disturbing read.