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Author Topic: The Holocene Extinction  (Read 34064 times)

Bruce Steele

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Re: The Holocene Extinction
« Reply #350 on: September 30, 2019, 11:08:00 PM »
Vox-mundi, I thought your latest post belonged here as well. Some of the birds listed, blue birds and olive sided flycatchers are here on my farm and I noted earlier a decrease in the blue bird numbers. I think roadrunners are also in decline and the highway serves as a very long term chronic mortality source.
https://www.audubon.org/field-guide/bird/olive-sided-flycatcher

Re: Heatwaves
« Reply #381 on: Today at 10:45:32 PM »
Collapse of Desert Bird Populations Likely Due to Heat Stress from Climate Change
https://phys.org/news/2019-09-collapse-bird-populations-due-stress.html

As temperatures rise, desert birds need more water to cool off at the same time as deserts are becoming drier, setting some species up for a severe crash, if not extinction, according to a new study from the University of California, Berkeley.

... The researchers' latest findings, part of UC Berkeley's Grinnell Resurvey Project, come from comparing levels of species declines to computer simulations of how "virtual birds" must deal with heat on an average hot day in Death Valley, which can be in the 30s Celsius—90s Fahrenheit—with low humidity. These temperatures are, on average, 2 C (3.6 F) hotter than 100 years ago. The birds that the model predicted would require the most extra water today, compared to a 100 years ago, were the species that had declined the most in the Mojave Desert over the past century. The desert straddles the border between California and Nevada.

The most threatened turn out to be larger birds, and those that have an insect or animal diet.

The team calculated that larger birds, like the mourning dove, require 10% to 30% more water today to keep cool because of the 2 C increase in Mojave Desert temperatures over the last 100 years.



According to the UC Berkeley analysis, birds that eat insects or other animals are more threatened by changes in evaporative water loss because they typically get all of their water from the moisture in their food. They seldom, if ever, drink from surface water sources. A 30% increase in water requirement could mean that larger birds have to catch an extra 60 to 70 bugs per day to survive the increased heat. If those bugs are even around, the birds still have to expend extra energy and time to find them.

The American kestrel, prairie falcon and turkey vulture, all large and carnivorous, have declined, as have large insect-eaters like the white-throated swift, violet-green swallow, olive-sided flycatcher, Western meadowlark and Western bluebird.

Smaller birds that eat seeds or are omnivores are less threatened, according to the model.

Vegetarian birds, such as seedeaters, face a different problem. Because they can drink from surface water sources—springs and pools in desert oases, they can supplement the water they get from their food. But that's only if water is around.

... According to Beissinger, the team's conclusions about these California and Nevada desert birds may apply to species in other regions of the world.

Eric A. Riddell el al., "Cooling requirements fueled the collapse of a desert bird community from climate change," PNAS (2019)
 Logged
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late
« Last Edit: September 30, 2019, 11:26:45 PM by Bruce Steele »

vox_mundi

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Re: The Holocene Extinction
« Reply #351 on: October 01, 2019, 01:24:09 AM »
Thanks, Bruce  :)

Here on the East coast the survivors seem to be omnivores, seed and fruitovores. That said, the bird population here has crashed. Some days, I can count the number of birds I see in one day on one hand.

Fortunately, we have plenty of water.
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

vox_mundi

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Re: The Holocene Extinction
« Reply #352 on: October 03, 2019, 06:45:38 PM »
Booming Demand Driving Tuna to Extinction, Researchers Find
https://www.theguardian.com/environment/2019/oct/03/booming-demand-for-tuna-driving-unsustainable-level-of-fishing-report

Scientists have warned that existing levels of tuna fishing are unsustainable after researchers found that global catches have increased more than 1,000% over the past 60 years.

A study in the journal Fisheries Research estimated that about 6m tonnes of tuna are now caught annually, a rate that “risks driving tuna populations to unsustainable levels and possible extinction”.

... The decline of tuna populations could threaten food supply chains and jobs around the world, as well as potentially destabilising the underwater food web, Coulter said. “Tuna are both predators and prey. They eat smaller fish and invertebrates and are a food source for larger marine life, such as sharks and whales.

“If we lose tuna due to overexploitation, we break those links in the food web and disrupt the function of the ecosystem. This means that the survival of other species in the ecosystem is also threatened,” she said.


Fig.3: Global catches of tuna and other large pelagic fishes from 1950 to 2016 as assembled and harmonized from the five separate tuna RFMO datasets, by a) ocean basins; b) major taxa (156 additional taxa are pooled in ‘Other’); and c) important taxa beyond the 12 major target species covered in the FAO Atlas of Tuna and Billfish Catches (144 additional taxa are pooled in ‘Other’).

AngieCoulter, et.al., Using harmonized historical catch data to infer the expansion of global tuna fisheriesFisheries Research, 2020
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

TerryM

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Re: The Holocene Extinction
« Reply #353 on: October 03, 2019, 11:53:02 PM »
Vox
You might want to run some of these overfishing stories past Bruce. He's an excellent source of 1st hand information regarding the oceans & fishing. Sometimes the explanations aren't quite as one sided as they might at first appear.
Terry

vox_mundi

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Re: The Holocene Extinction
« Reply #354 on: October 04, 2019, 12:20:18 AM »
Thanks Terry

I think, though, tuna (and related species) are seriously stressed, especially bluefin. And we're working down the food chain.

As a keystones species it's having ripple effects in the rest of the ecosystem.

I do recall reading of a aquaculturist, possible in Australia, who had successfully farm raised bluefin. I haven't heard anything more, so that may have been a one shot wonder.

These meta-studies have the advantage of giving a systems level view of the subject that may not be obvious at the regional level.
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

Bruce Steele

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Re: The Holocene Extinction
« Reply #355 on: October 04, 2019, 06:43:10 AM »
Terry, There are lots of different tuna and different stocks around the world and I am no expert. I did fish albacore for a couple months out by the 200 mile line on a 38 ft. jig boat. Land was days away.
Not all the stocks are in bad shape . You might keep in mind that there hasn’t been a single fish species driven to extinction by commercial fishing. So I get a little put off when “ extinction “ is in the title. I did read the article ( part way )but it seemed solely based on fish landing data, kinda boring...My scientific review.

kassy

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Re: The Holocene Extinction
« Reply #356 on: October 04, 2019, 11:09:28 PM »
Climate change pushes Italy beekeepers to the brink

https://phys.org/news/2019-10-climate-italy-beekeepers-brink.html

Black year for European beekeepers

This year has been a black one for many European beekeepers, particularly in France and Italy, where unpredictable weather has produced what are being termed the worst honey harvests ever.

https://phys.org/news/2019-10-black-year-european-beekeepers.html

Of course the weird weather also influences all kinds of less monitored wild species.
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

vox_mundi

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Re: The Holocene Extinction
« Reply #357 on: October 09, 2019, 01:53:31 PM »
Botswana Rhinos Risk Wipeout as Poaching Rises
https://phys.org/news/2019-10-botswana-rhinos-wipeout-poaching.html

Nine Botswana rhinos have been poached since April, the government said Wednesday, an unprecedented rate of one per month that could see rhinos wiped out in the southern African country by 2021.

... Sold for up to 55,000 euros ($60,300) per kilo on the black market, rhino horn is used in traditional medicine or as a symbol of wealth and success.

Botswana's neighbour South Africa lost more than 7,100 rhinos over the past decade, including 769 in 2018.

Namibia has also recorded recent incidents of rhino poaching, which leaves the animal bleeding to death after its horn is hacked off.
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

vox_mundi

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Re: The Holocene Extinction
« Reply #358 on: October 10, 2019, 06:35:11 PM »
Two-Thirds of Bird Species in North America Could Vanish in Climate Crisis
https://www.theguardian.com/environment/2019/oct/10/bird-species-extinction-north-america-climate-crisis

Continent could lose 389 of 604 species studied to threats from rising temperatures, higher seas, heavy rains and urbanization

Bird extinctions are yet another face of the human-caused biodiversity crisis threatening up to a million animal and plant species. A related study from Cornell University last month found the US and Canada lost one in four birds – or 3 billion total – since 1970.

“Birds are indicators of the health of our environment, so if they disappear, we’re certainly going to see a lot of changes in the landscape,” said Brooke Bateman, the senior researcher who wrote the report. “If there are things changing with birds we have to understand that the environment is changing for us as well.”
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

Hefaistos

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Re: The Holocene Extinction
« Reply #359 on: October 12, 2019, 06:56:00 PM »
OTOH:
The world is literally a greener place than it was 20 years ago.
"Taken all together, the greening of the planet over the last two decades represents an increase in leaf area on plants and trees equivalent to the area covered by all the Amazon rainforests. There are now more than two million square miles of extra green leaf area per year, compared to the early 2000s – a 5% increase.

“But, now that we know direct human influence is a key driver of the greening Earth, we need to factor this into our climate models,” Nemani said. “This will help scientists make better predictions about the behavior of different Earth systems, which will help countries make better decisions about how and when to take action.”

The world is a greener place than it was 20 years ago, as shown on this map, where areas with the greatest increase in foliage are indicated in dark green. Data from a NASA instrument orbiting Earth aboard two satellites show that human activity in China and India dominate this greening of the planet."

More greens assumedely counteracts the "extinction". Or maybe it's all mono-culture greens where nothing else lives?
In any case, this is a real carbon sink.

https://www.nasa.gov/feature/ames/human-activity-in-china-and-india-dominates-the-greening-of-earth-nasa-study-shows

wili

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Re: The Holocene Extinction
« Reply #360 on: October 12, 2019, 07:08:01 PM »
I don't follow.

If this is mostly from ag products, where is the carbon sink. Maybe in the areas converting to no-till it could be, but where they are practicing traditional modern ag practices, there will be very little if any carbon sink...more likely carbon loss from degraded soils.

But perhaps I'm missing something here?
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Darvince

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Re: The Holocene Extinction
« Reply #361 on: October 13, 2019, 04:19:25 AM »
This... has basically nothing to do with the thriving of, especially, wild animal species. If I'm a farmer in north-west India and I plant a small garden of fruit trees outside my house, that means leaf area has increased, but it doesn't mean biodiversity has increased.

And, from your article:
Quote
The researchers point out that the gain in greenness seen around the world and dominated by India and China does not offset the damage from loss of natural vegetation in tropical regions, such as Brazil and Indonesia. The consequences for sustainability and biodiversity in those ecosystems remain.

Hefaistos

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Re: The Holocene Extinction
« Reply #362 on: October 13, 2019, 03:57:30 PM »
I don't follow.

If this is mostly from ag products, where is the carbon sink. Maybe in the areas converting to no-till it could be, but where they are practicing traditional modern ag practices, there will be very little if any carbon sink...more likely carbon loss from degraded soils.

But perhaps I'm missing something here?
Forestation might be considered a carbon sink, no? From the article:
"China’s outsized contribution to the global greening trend comes in large part (42%) from programs to conserve and expand forests. These were developed in an effort to reduce the effects of soil erosion, air pollution and climate change. Another 32% there – and 82% of the greening seen in India – comes from intensive cultivation of food crops."

The rest apart from forestation is more correctly describes as carbon sequestration. Assumedly it will be more intense if it's land that is exploited for ag production with multiple cropping.

vox_mundi

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Re: The Holocene Extinction
« Reply #363 on: October 22, 2019, 01:20:27 AM »
Dozens of Elephants Die in Zimbabwe Drought
https://phys.org/news/2019-10-dozens-elephants-die-zimbabwe-drought.html

At least 55 elephants have died in a month in Zimbabwe due to a lack of food and water, its wildlife agency said Monday, as the country faces one of the worst droughts in its history.

... An adult elephant drinks 680 litres (180 gallons) of water per day on average and consumes 450 kilogrammes (990 pounds) of food.

... Africa's elephant numbers have dropped from around 415,000 to 111,000 over the past decade, mainly due to poaching for ivory, according to the International Union for Conservation of Nature (IUCN).

... More than five million rural Zimbabweans—nearly a third of the population—are at risk of food shortages before the next harvest in 2020, the United Nations has warned.

----------------------

Drought Causes More Than 100 Elephant Deaths in Botswana
https://phys.org/news/2019-10-drought-elephant-deaths-botswana.html

More than 100 elephants have died in two months in Botswana's Chobe National Park due to drought, which has also affected wildlife in other countries in the region, the government said Tuesday.
« Last Edit: October 22, 2019, 11:50:03 PM by vox_mundi »
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late