Sixth Mass Extinction Event

[Volkonski]

Greetings fellow residents of the Anthropocene! This topic deserves a thread of its own.

What the ‘sixth extinction’ will look like in the oceans: The largest species die off first

https://www.washingtonpost.com/news/ene ... 75b2151993

From sharks to whales, giant clams, sea turtles, and tuna, the disproportionate threat to larger marine organisms reflects the “unique human propensity to cull the largest members of a population,” the authors write.

“What to us was surprising was that we did not see a similar kind of pattern in any of the previous mass extinction events that we studied,” said geoscientist Jonathan Payne of Stanford University, the study’s lead author. “So that indicated that there really is no good ecological analogue…this pattern has not happened before in the half billion years of the animal fossil record.”

The researchers conducted the work through a statistical analysis of a 2,497 different marine animal groups at one taxonomic level higher than the level of species — called “genera.” And they found that increases in an organism’s body size were strongly linked to an increased risk of extinction in the present period — but that this was not the case in the Earth’s distant past.



“These losses in the ocean are paralleling what humans did to land animals some 50,000 to 10,000 years ago, when we wiped out around half of the big-bodied mammal species on Earth, like mammoths, mastodons, saber-tooth cats and the like,” said Anthony Barnosky, executive director of Stanford Jasper Ridge Biological Preserve, who was not involved in the study but reviewed it for the Post. “As a result, terrestrial ecosystems were locked into a new trajectory that included local biodiversity loss over and above the loss of the large animals themselves, and changes in which kinds of plants dominated.”

[Volkonski]

Ecological selectivity of the emerging mass extinction in the oceans

http://science.sciencemag.org/content/e ... ce.aaf2416

Abstract

To better predict the ecological and evolutionary effects of the emerging biodiversity crisis in the modern oceans, we compared the association between extinction threat and ecological traits in modern marine animals to associations observed during past extinction events using a database of 2497 marine vertebrate and mollusc genera. We find that extinction threat in the modern oceans is strongly associated with large body size, whereas past extinction events were either nonselective or preferentially removed smaller-bodied taxa. Pelagic animals were victimized more than benthic animals during previous mass extinctions but are not preferentially threatened in the modern ocean. The differential importance of large-bodied animals to ecosystem function portends greater future ecological disruption than that caused by similar levels of taxonomic loss in past mass extinction events.

Terrestrial biodiversity is declining rapidly (1), and the oceans are poised to follow suit without intervention (2). This “sixth mass extinction” may approach or exceed the magnitude of the five major extinctions of the past 550 million years (My) if current loss rates persist (3). Because the effects of massive diversity loss are difficult to scale upward from laboratory experiments or local ecosystem disruptions (4), ancient extinction events provide critical information for forecasting the structure and function of the future biosphere. Previous attempts to contextualize present threats using past extinctions focused mainly on extinction intensity (rate and magnitude of taxonomic loss) [e.g., (3, 5)]. However, the distribution of losses across ecological functional groups (e.g., predators versus nonpredators) also strongly affects postextinction ecosystem function. Indeed, the preferential loss of dominant functional groups characterizes the two most important, era-bounding mass extinctions (6): the end-Permian event [252 million years ago (Ma)] exterminated all reef-building animals, and the end-Cretaceous (66 Ma) eliminated the nonavian dinosaurs.

[Volkonski]

Avian extinction rates are increasing.



http://evolution.berkeley.edu/evolibrar ... extinct_10

[Mikedunford]

It's been about 15 years, but I've done a lot of reading and research on mass extinctions. As a direct result, I'm very skeptical of most of the papers that present specific claims on rates.

I should note right now that I don't have any doubts about the actual threat to species that humanity is causing, just the attempts to put such specific numbers on it.

Basically, my objections boil down to two main points:
1: On the change in rates historically, and particularly the bird rate changes, I think that a lot of the effect can be attributed to gains in our knowledge baseline - we see more species going extinct because we've put in more time looking for already-rare species, and we've put in more time and effort tracking those we know about. That's something that I'm sure researchers are aware of, but it's spectacularly hard to account for when conducting research like this.

And that effect is likely to be particularly large when we're looking at birds. First, birds are charismatic, and people have put in particularly huge efforts to find and identify rare bird species - with much of that work taking place in the 19th and 20th centuries, which coincides with the increase in extinctions identified in the graph. Second, identifying birds that went extinct prior to that search (through the use of sub-fossils) is complicated by the fact that the very features that make birds great at flying also make them horrible at turning into fossils. (Small, light, hollow bones.)

2: On the fossil record comparisons, the problem with the fossil record is that it's highly selective. Marine invertebrates (like mollusks) are much more likely to leave fossils than marine vertebrates. This, in turn, means that any statement about extinction rates of vertebrates in the past is complicated by the lack of good record. Further complicating things, there's the issue of naming fossil species. Different paleontologists tend to specialize in different parts of the geological column, and that can lead to different parts of the community studying the same group of organisms to develop different standards for deciding when something is a different species. Add in the nature of the fossil record (we can study the rocks we can access), and it becomes very difficult to say that our understanding of the past is based on a firm knowledge of what was happening to organisms at the species level across the entire planet at any time.

Again, no doubts here that we're doing irreparable harm to biodiversity - just to any claims that we can make solid comparisons between now and past extinctions.

[Volkonski]

Do Species Matter?

http://www.themillbrookindependent.com/ ... ies-matter

But, suppose we strip the question down to its bare bones: is there evidence that species make a difference? We lost the Passenger Pigeon and (for the most part) American Chestnut, and life seemed to go on pretty well without them. The Blue Tuna is close to extinct, to the distress of a few connoisseurs of raw sushi. And a small rodent on the Great Barrier Reef of Australia, the Bramble Cay Melomys, may have been the first mammal to disappear from climate change. Do these species matter?

An increasing body of scientific work suggests that a diverse world—what biologists call high biodiversity—is a healthier world. Working at the Cary Institute in Millbrook, NY, Rick Ostfeld has shown that the prevalence of Lyme disease and other tick-borne illness is more widespread in areas where the natural diversity of birds and mammals has been reduced by suburbanization. We should expect the same for the prevalence of the Zika virus, carried by mosquitoes.

In field experiments, where ecologists have excluded the presence of birds in the forest canopy, the level of insect herbivory increases markedly, reducing the growth of trees. Foresters should take note: a diverse forest is likely to have a high diversity of birds compared to a plantation forest of a single species. Other experiments in grasslands have shown that the more diverse the field, the greater resistance the grassland shows to periodic droughts and other perturbations that it may face.



We don’t know where we are along the path of declining biodiversity, except that the current rate of loss is well in excess of what is seen in the geological record. We know that humans have driven some species extinct, and it is likely that 10 billion humans will lead to more extinctions. By one reckoning, a loss of 20% of the species puts an ecosystem at risk. One estimate suggests that 18 to 35% of extant species will go extinct because of climate change in this century. Even if we pick the lower boundary of this estimate, the chance of losing the critical rivet seems too great to take.

[Volkonski]

https://www.washingtonpost.com/news/ani ... cary-ones/

But it’s complicated, for a few reasons. The world’s human population is on a course to hit 9.7 billion by 2050, and all those people are going to need more to eat. If we keep using today’s food production methods, that will require more land for crops and cows, chickens and other meat sources, which will mean less habitat for wild animals (and could catalyze a sixth “mass extinction“).

We have had some success saving species by banning the hunting of them. However, we can only do that once. If habitat destruction continues then extinctions will happen anyway. We will eat the planet to death.

[Volkonski]

The cats are helping us eat the world to death.

Cats really are evil though not as evil as we humans.

Feral cats one of biggest contributors to sixth mass extinction

http://www.ibtimes.com.au/feral-cats-on ... on-1529154

To protect the Night Parrot, Australia has targeted to kill 20 million feral cats. The decision is apparently in the right direction because a global analysis published in the Proceedings of the National Academies of Sciences blames the animal for driving at least 63 species of birds, mammals and reptiles into extinction the past 500 years.

Feral cats, though, are less harmful than rodents which are linked to the extinction of 75 species. Dogs, meanwhile, are responsible for the extinction of a dozen species.

Tim Doherty, of Deakin University in Australia, is seeking the holding of a wider study to document the effect of introduced predators on a global scale. He says a worldwide assessment across all regions and predator species would provide scientists with information to allow them to determine the impact of invasive predators across predators, prey species and geographic locations.

Data from the International Union for Conservation of Nature’s Red List named the predators as rodents, cats, dogs, pigs, red foxes and small Indian mongooses. These invasive predators contributed to at least 87 bird, 45 mammal and 10 reptile extinctions, or over 50 percent of all known extinctions in those groups. Meanwhile, carnivores are threatening 596 species, reports Gizmodo.

[Volkonski]

Wildlife Populations Have Dropped by Almost 60% in 40 Years, WWF Says

http://time.com/4547132/wildlife-popula ... cline-wwf/

Global wildlife populations have plummeted by 58% between 1970 and 2012, according to the latest Living Planet Report published by conservation group WWF on Wednesday.

The report — an analysis of data on more than 14,200 populations across 3,700 species of mammals, fish, amphibians, birds and reptiles — projected that if the trend continued, the world could lose more than two-thirds of wildlife by 2020.

Worst affected are species that live in lakes, rivers and wetlands — these freshwater dwellers have seen an 81% drop in populations over the past four decades, according to WWF.

The rapid rate of decline is attributed to rising human populations, habitat loss and degradation, hunting and climate change.

[Sterngard Friegen]

Have other declines been as rapid? In what ways is this abnormal when a new clade arises that is more successful than prior ones?

[TollandRCR]

Have other declines been as rapid? In what ways is this abnormal when a new clade arises that is more successful than prior ones?

We were not around for the other five mass extinctions. We would probably/certainly have been victims in them. The BBC has a good page on the Big Five mass extinction events. Some of those earlier events took hundreds of thousands or millions of years. One of the earliest extinctions involved the introduction into the atmosphere of a poison gas -- oxygen. This was the fault of photosynthetic plants.

Most of the current mass extinction is invisible to most of us. I think of us as being preoccupied with large furry animals and ignorant of the fungi and worms. When E. O. Wilson accepted the 2007 TED prize, he gave a talk on behalf of his constituents, the 10¹⁸ insects and other small creatures. http://www.ted.com/talks/e_o_wilson_on_ ... anguage=en

[Volkonski]

OK, things are worse than previously reported on this matter.

http://www.cnn.com/interactive/2016/12/ ... d=32516250

[RoadScholar]

I've always thought the future as depicted in Bladerunner to be ominously plausible.

[RTH10260]

OK, things are worse than previously reported on this matter.

http://www.cnn.com/interactive/2016/12/ ... d=32516250

Hmmm - any indication that Homo Sapiens Sapiens is among the survivors

[Volkonski]

Primates facing 'extinction crisis'

"Forests are destroyed when primate habitat is converted to industrial agriculture, leaving primates with nowhere to live," she told BBC News.

"And primates are hunted for meat and trade, either as pets or as body parts."

Other threats - all driven by human behaviour - are forest clearance for livestock and cattle ranching; oil and gas drilling and mining.

"The short answer is that we must reduce human domination of the planet, and learn to share space with other species," Prof Setchell commented.

Currently 60% of primate species are at risk of extinction.

[RoadScholar]

We are pointed toward the future seen in Blade Runner, and lots of people don't seem to care. I don't get it.

[kate520]

Climate change is as fictional to them as Blade Runner.

[Foggy]

Blade Runner without the opportunity to migrate to another planet....

[RoadScholar]

Egad! Right you are.

[Volkonski]

Size matters when it comes to extinction risk

http://www.bbc.com/news/science-environment-41279470

Heavyweights are threatened mainly by hunting, while featherweights are losing out to pollution and logging.



The research adds to evidence that animals are dying out on such a scale that a sixth extinction is considered under way.



Yet, when the researchers made a data base of thousands of birds, mammals, fish, amphibians and reptiles at risk of extinction, they found disproportionate losses at the large and small ends of the scale.

"Surprisingly, we found that not only the largest of all vertebrate animal species are most threatened, but the very tiniest ones are also highly threatened with extinction," Prof Ripple told BBC News.

[Volkonski]

This is bad. This is very bad.

New study suggests insect populations have declined by 75% over 3 decades

http://www.cnn.com/2017/10/19/europe/in ... index.html

A new scientific study has found "dramatic" and "alarming" declines in insect populations in areas in Germany, which researchers say could have far-reaching consequences for the world's crop production and natural ecosystems.

The study, published on Wednesday in peer-reviewed journal PLOS One has found that, in German nature reserves, flying insect populations have declined by more than 75% over the duration of the 27-year study.



"Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services."



"Insects pollinate the crops we eat, they contribute to pest control, we'd have to use more pesticide. They're even crucial in waste control -- most of the waste in urban areas is taken care of by ants and cockroaches."

[Volkonski]

https://theconversation.com/how-changin ... tion-81061

Transforming large swaths of the tropics into farmland could render almost one-third of wildlife there extinct, new research suggests.

From the Amazon rain forests to the Zambezi floodplains, intensive monoculture farming could have a severe adverse impact on wildlife around the world.

Wildlife would disappear most dramatically in the remaining forests and grasslands of Latin America and Sub-Saharan Africa. The greatest species loss would occur in the Peruvian Amazon basin where as many as 317 species could vanish as a result of agricultural development.

As a doctoral researcher at Humboldt University Berlin, I studied human food consumption, land use and how they affect wildlife. Our research was published July 17 in Nature Ecology and Evolution.
While human population has doubled since 1970, the number of birds, mammals, reptiles and amphibians have dropped by more than half. At its root, this widespread environmental destruction is a result of our growth as a species and increasing food consumption to sustain ourselves.

[Volkonski]

The Guardian
✔
@guardian

North Atlantic right whales may face extinction after no new births recorded
https://
trib.al/D7nMhrU

4:26 PM - Feb 26, 2018

[quote]Scientists observing the whale community off the US east coast have not recorded a single mother-calf pair this winter. Last year saw a record number of deaths in the population. Threats to the whales include entanglement in lobster fishing ropes and an increasing struggle to find food in abnormally warm waters.

The combination of rising mortality and declining fertility is now seen as potentially catastrophic. There are estimated to be as few as 430 North Atlantic right whales left in the world, including just 100 potential mothers.

“At the rate we are killing them off, this 100 females will be gone in 20 years,” said Mark Baumgartner, a marine ecologist at the Woods Hole Oceanographic Institution in Massachusetts. Without action, he warned, North Atlantic right whales will be functionally extinct by 2040.[/quote]

[Sterngard Friegen]

Life always finds a way. It’s just different life. We shouldn’t be specieist.

[TollandRCR]

https://theconversation.com/how-changin ... tion-81061

Transforming large swaths of the tropics into farmland could render almost one-third of wildlife there extinct, new research suggests.

From the Amazon rain forests to the Zambezi floodplains, intensive monoculture farming could have a severe adverse impact on wildlife around the world.

Wildlife would disappear most dramatically in the remaining forests and grasslands of Latin America and Sub-Saharan Africa. The greatest species loss would occur in the Peruvian Amazon basin where as many as 317 species could vanish as a result of agricultural development.

As a doctoral researcher at Humboldt University Berlin, I studied human food consumption, land use and how they affect wildlife. Our research was published July 17 in Nature Ecology and Evolution.
While human population has doubled since 1970, the number of birds, mammals, reptiles and amphibians have dropped by more than half. At its root, this widespread environmental destruction is a result of our growth as a species and increasing food consumption to sustain ourselves.

Often when we speak of “wildlife” we do not consider beetles, slime molds, fungi, nematodes, or frogs. The world is more than mammals, birds, fish, and large reptiles. I would guess that hundred of species would be at risk.

Some of those species may turn out to be important to us or other species. The great chain of being is wonderfully complex.

[maydijo]

[quote]Scientists observing the whale community off the US east coast have not recorded a single mother-calf pair this winter. Last year saw a record number of deaths in the population. Threats to the whales include entanglement in lobster fishing ropes and an increasing struggle to find food in abnormally warm waters.

The combination of rising mortality and declining fertility is now seen as potentially catastrophic. There are estimated to be as few as 430 North Atlantic right whales left in the world, including just 100 potential mothers.

“At the rate we are killing them off, this 100 females will be gone in 20 years,” said Mark Baumgartner, a marine ecologist at the Woods Hole Oceanographic Institution in Massachusetts. Without action, he warned, North Atlantic right whales will be functionally extinct by 2040.

[/quote]

This pertains to southern right whales, so a different species; but when Shackleton first sailed to Antarctica he said words to the effect that the southern right whales were so numerous, he could've walked to Antarctica across their backs. That was in 1916, so just a little over 100 years ago. It's pathetically sad what we do to this world.