Biodiversity decline megathread

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Bird on a Fire
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Biodiversity decline megathread

Post by Bird on a Fire » Thu Mar 04, 2021 5:54 am

A couple of these today.

UK Seagrass meadows: 90% gone.

Some cool facts about seagrass meadows:
Seagrass flowers are pollinated by shrimps and other creatures, as well as water currents. The meadows can store carbon 35 times faster than tropical rainforests and harbour up to 40 times more marine life than bare seabeds.
No deep discussion of what's caused the declines. This article cites "the impact of coastal development on seagrass ecosystems, including eutrophication and habitat loss due to dredging, anchoring and coastal infrastructure".


Also, UK moths: down a third in 50 years.
“This decline is worrying because moths play a vital role in our ecosystems,” said Richard Fox of Butterfly Conservation, which produced the report with Rothamsted Research and the UK Centre for Ecology & Hydrology. “They are pollinators of many plants, with some wildflowers, such as orchids, relying on visiting moths for reproduction. They also provide essential food for thousands of animal species, including bats and many familiar birds.”
According to Fox the prime driver for the declines is likely to be habitat loss and more intensive agriculture, including chemical farming, but other important factors include climate change and, possibly, increased nitrogen deposition and light pollution.

“No species will be totally immune from all these different factors,” he said. “Even moths living at the top of a Scottish mountain will be impacted by climate change and nitrogen deposition.”
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Re: Biodiversity decline megathread

Post by Fishnut » Thu Mar 04, 2021 1:13 pm

19 ecosystems in Australia are collapsing:
  • Great Barrier Reef
  • Australian tropical savannas
  • Mangrove forests in the Gulf of Carpentaria
  • Wet tropical rainforest in North Queensland
  • Western-central arid zones
  • Georgina Gidgee Woodlands, central Australia
  • Ningaloo Reef, northern Western Australia
  • Shark Bay seagrass communities, Western Australia
  • Murray Darling river basin - waterways
  • Murray Darling river basin - riverine
  • Montane and sub-alpine forests, South Australia, New South Wales and the Victorian highlands
  • Great Southern Reef Kelp Forests, southern Australia
  • Mediterranean-type forests and woodlands
The Murray Darling is an absolutely massive river basin, stretching from southern Queensland down to the southern coast of Australia (I had no idea how big or important it was until I attended a couple of talks on it at my last fisheries conference). It's under significant pressure from water extraction and there's been significant mass mortality events in recent years where lakes and side-rivers have dried up. In 2019 two events in quick succession occurred, the first killing about 10,000 fish, the second killing 100 times that. A lot of the native species are at risk of extinction because of overfishing and loss of habitat, and these mass mortalities make their continuing existence even more precarious.
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Re: Biodiversity decline megathread

Post by Bird on a Fire » Wed Mar 17, 2021 4:21 pm

Interesting blog on the lost rainforests of England, and a project to crowdsource mapping of them. Anyone familiar with the Westcountry (around Dartmoor, Exmoor and Bodmin Moor), the Lake District, the Forest of Bowland, the Yorkshire Dales, and the Pennines etc. could help out.
Few people realise that Britain harbours fragments of a globally rare habitat: temperate rainforest.

Everyone’s heard of tropical rainforests. But we also have rainforests in Europe! Temperate rainforests occur in mid-latitude, temperate zones, in places which receive heavy rainfall due to an ‘oceanic’ climate.

Put more simply: temperate rainforests are very damp woodlands – so damp that plants grow on other plants. These plants are known as ‘epiphytes’. If you want to recognise temperate rainforest in Britain, the key indicator is an abundance of mosses, lichens and polypody ferns festooning the branches and trunks of trees.
https://lostrainforestsofengland.org/20 ... ainforest/

Very few people know that England once supported large expanses of temperate rainforest, in a swathe across the western upland parts of the country – from the Lake District in the north, through the Pennines, Dales and Forest of Bowland, to Dartmoor, Exmoor and Bodmin Moor in the Westcountry. They were felled by Bronze Age settlers, medieval tin-miners, Victorian charcoal-makers, and in the modern era by foresters who replaced them with high-yield conifers for timber. Blanket bog formed over large areas of the uplands, deterring the return of dense woodland, and overgrazing by sheep has prevented their regrowth on the hillsides and in the cloughs.

Yet despite all this, pockets of temperate rainforest cling on in England today. They huddle in lost valleys and sprout from piles of scree where boulders prevent even the surest-footed sheep from nibbling fresh saplings. What’s more, they could yet spread further, if we give them the space to grow and protect them from overgrazing. Indeed, as I’ll show in later posts on this blog, some of England’s rainforests are already expanding through natural regeneration.
https://lostrainforestsofengland.org/20 ... f-england/

The author is Guy Shrubsole who wrote Who Owns England?.
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Re: Biodiversity decline megathread

Post by Bird on a Fire » Wed Mar 17, 2021 4:25 pm

A sad one from Australia: a bird that's become so rare, young males can't learn how to sing, and therefore can't attract mates, thus exacerbating the population's decline:
Populations have reached such low numbers that young males are not getting a chance to learn mating calls from other adults, according to Dr Ross Crates, an ecologist at the Fenner school of environment and society at the Australian National University.

“The poor birds are not getting the chance to to learn what they should be singing,” Crates said.

When regent honeyeaters emerge as chicks, the males stay relatively quiet to avoid attracting attention to their newborn. This means it is not until later that the juveniles learn the mating songs from adult males.

But if there aren’t enough of those around, according to Crates, then they will just pick up the calls of other birds. And those calls are not what female regent honeyeaters are listening out for.

Crates’ study, in the journal Proceedings of the Royal Society B, suggests that these birds that don’t learn to sing their usual song are less likely to find a partner.
https://www.theguardian.com/environment ... love-songs

These kinds of density-dependent effects are known as Allee effects, or when things get this dire are sometimes called an 'extinction vortex'.

Full paper is here but I can't read it because sci hub isn't working. https://royalsocietypublishing.org/doi/ ... .2021.0225
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Re: Biodiversity decline megathread

Post by Bird on a Fire » Wed Mar 17, 2021 4:26 pm

Fishnut wrote:
Thu Mar 04, 2021 1:13 pm
19 ecosystems in Australia are collapsing:
  • Great Barrier Reef
  • Australian tropical savannas
  • Mangrove forests in the Gulf of Carpentaria
  • Wet tropical rainforest in North Queensland
  • Western-central arid zones
  • Georgina Gidgee Woodlands, central Australia
  • Ningaloo Reef, northern Western Australia
  • Shark Bay seagrass communities, Western Australia
  • Murray Darling river basin - waterways
  • Murray Darling river basin - riverine
  • Montane and sub-alpine forests, South Australia, New South Wales and the Victorian highlands
  • Great Southern Reef Kelp Forests, southern Australia
  • Mediterranean-type forests and woodlands
The Murray Darling is an absolutely massive river basin, stretching from southern Queensland down to the southern coast of Australia (I had no idea how big or important it was until I attended a couple of talks on it at my last fisheries conference). It's under significant pressure from water extraction and there's been significant mass mortality events in recent years where lakes and side-rivers have dried up. In 2019 two events in quick succession occurred, the first killing about 10,000 fish, the second killing 100 times that. A lot of the native species are at risk of extinction because of overfishing and loss of habitat, and these mass mortalities make their continuing existence even more precarious.
Australia is impressively awful at conservation. It goes to ram home the point that neither lack of knowledge nor lack of money are the problem, but rather lack of political will.
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Re: Biodiversity decline megathread

Post by bjn » Wed Mar 17, 2021 5:13 pm

Australia is dominated by a "if it moves shoot it if it doesn't dig it up" attitude, the whole idea of a true Australian being someone who is either chopping things down or digging things up. Many sections (hopefully growing) disagree with that, but if you do you are an impractical Greenie who is against jobs 'n growth. Many of large primary industries have evolved since white settlement and they aren't going away, it's not going to change any time soon. c.f. The Adani Mine in Queensland.

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Re: Biodiversity decline megathread

Post by Fishnut » Wed Mar 17, 2021 5:17 pm

When your Prime Minister brings a lump of coal into parliament (admittedly, when he was just an MP) and tells people "don't be scared" it's pretty safe to say the environment isn't high on their concerns.
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Re: Biodiversity decline megathread

Post by monkey » Wed Mar 17, 2021 5:54 pm

Bird on a Fire wrote:
Wed Mar 17, 2021 4:25 pm
A sad one from Australia: a bird that's become so rare, young males can't learn how to sing, and therefore can't attract mates, thus exacerbating the population's decline:
Populations have reached such low numbers that young males are not getting a chance to learn mating calls from other adults, according to Dr Ross Crates, an ecologist at the Fenner school of environment and society at the Australian National University.

“The poor birds are not getting the chance to to learn what they should be singing,” Crates said.

When regent honeyeaters emerge as chicks, the males stay relatively quiet to avoid attracting attention to their newborn. This means it is not until later that the juveniles learn the mating songs from adult males.

But if there aren’t enough of those around, according to Crates, then they will just pick up the calls of other birds. And those calls are not what female regent honeyeaters are listening out for.

Crates’ study, in the journal Proceedings of the Royal Society B, suggests that these birds that don’t learn to sing their usual song are less likely to find a partner.
https://www.theguardian.com/environment ... love-songs

These kinds of density-dependent effects are known as Allee effects, or when things get this dire are sometimes called an 'extinction vortex'.

Full paper is here but I can't read it because sci hub isn't working. https://royalsocietypublishing.org/doi/ ... .2021.0225
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Re: Biodiversity decline megathread

Post by Squeak » Wed Mar 17, 2021 9:24 pm

Fishnut wrote:
Thu Mar 04, 2021 1:13 pm
19 ecosystems in Australia are collapsing:
That's my PhD supervisor's paper. And I note it doesn't include the ecosystem that we identified as collapsing on Macquarie island, probably because it's far too small to make that list. :(

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Re: Biodiversity decline megathread

Post by Fishnut » Wed Mar 17, 2021 10:00 pm

Squeak wrote:
Wed Mar 17, 2021 9:24 pm
Fishnut wrote:
Thu Mar 04, 2021 1:13 pm
19 ecosystems in Australia are collapsing:
That's my PhD supervisor's paper. And I note it doesn't include the ecosystem that we identified as collapsing on Macquarie island, probably because it's far too small to make that list. :(
Wow, that's depressing. I thought Macquarie was doing better now. How badly mistaken am I?
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Re: Biodiversity decline megathread

Post by Squeak » Wed Mar 17, 2021 11:36 pm

Fishnut wrote:
Wed Mar 17, 2021 10:00 pm
Squeak wrote:
Wed Mar 17, 2021 9:24 pm
Fishnut wrote:
Thu Mar 04, 2021 1:13 pm
19 ecosystems in Australia are collapsing:
That's my PhD supervisor's paper. And I note it doesn't include the ecosystem that we identified as collapsing on Macquarie island, probably because it's far too small to make that list. :(
Wow, that's depressing. I thought Macquarie was doing better now. How badly mistaken am I?
The rabbit, rat, and mouse eradication was a roaring success and the coastal vegetation is doing wonderfully as a result. I spent two summers face down in the vegetation before the eradication and had no idea there were any spiders on the island and the summer after the eradication, the coastal grasslands turned properly silver with webs as the spider population experienced a massive predation release. All sorts of things are in flux at the moment as the coasts find a new equilibrium.

Sadly, changing rainfall/cloud/evapotranspiration patterns on the plateau mean the cushion plants started dying a decade ago and those cushion plants literally anchor the rest of the feldmark ecosystem. They provide shelter and carbon for everything else, from ferns and grasses and mosses, to Collembola and other inverts. Without cushion plants, you get gravel and ultramafic soils and nothing else.

Given that cushion plants grow 1mm a year and three dry* years in a row kills them, it's pretty precarious. A lot of those dying cushion plants are thousands of years old.

* Their roots have almost no functional xylem, so dry doesn't mean a shortage of rainfall, it means fewer days with mist/low cloud to keep the leaves damp. Macquarie island rainfall has increased in recent decades but the rain has come as big dumps interspersed with sunny days, when it used to be consistently drizzly and misty. It was a surprisingly hard pattern to unpick from available data but quite neat when we finally put it all together.

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Re: Biodiversity decline megathread

Post by Fishnut » Wed Mar 17, 2021 11:49 pm

Squeak wrote:
Wed Mar 17, 2021 11:36 pm
Fishnut wrote:
Wed Mar 17, 2021 10:00 pm
Squeak wrote:
Wed Mar 17, 2021 9:24 pm
That's my PhD supervisor's paper. And I note it doesn't include the ecosystem that we identified as collapsing on Macquarie island, probably because it's far too small to make that list. :(
Wow, that's depressing. I thought Macquarie was doing better now. How badly mistaken am I?
The rabbit, rat, and mouse eradication was a roaring success and the coastal vegetation is doing wonderfully as a result. I spent two summers face down in the vegetation before the eradication and had no idea there were any spiders on the island and the summer after the eradication, the coastal grasslands turned properly silver with webs as the spider population experienced a massive predation release. All sorts of things are in flux at the moment as the coasts find a new equilibrium.

Sadly, changing rainfall/cloud/evapotranspiration patterns on the plateau mean the cushion plants started dying a decade ago and those cushion plants literally anchor the rest of the feldmark ecosystem. They provide shelter and carbon for everything else, from ferns and grasses and mosses, to Collembola and other inverts. Without cushion plants, you get gravel and ultramafic soils and nothing else.

Given that cushion plants grow 1mm a year and three dry* years in a row kills them, it's pretty precarious. A lot of those dying cushion plants are thousands of years old.

* Their roots have almost no functional xylem, so dry doesn't mean a shortage of rainfall, it means fewer days with mist/low cloud to keep the leaves damp. Macquarie island rainfall has increased in recent decades but the rain has come as big dumps interspersed with sunny days, when it used to be consistently drizzly and misty. It was a surprisingly hard pattern to unpick from available data but quite neat when we finally put it all together.
Oh god, that's awful. The pest eradication was such a huge deal, to hear that it might not even matter because of climate change is devastating.
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Re: Biodiversity decline megathread

Post by Squeak » Thu Mar 18, 2021 3:32 am

The eradication is an unquestionably good thing. It's enormously important for nesting birds and for the coastal plant communities and for the geomorphological values of the island. It's a world heritage area because it's a rare bit of mid-sea boundaries being stuck above water, not because of its biodiversity. But all the rabbit warrens were muddling up the soils and causing collapses, which was problematic in itself.

It's just that the feldmark communities on the plateau have a different set of stressors. There were never that many rabbits or mice up there (we looked for spatial relationships between rabbit tooth scrapings and dieback but couldn't find any).

Sadly, the cushion plants are particularly hard to germinate out two keep in captivity. And if you collect from the wild, they look fine and healthy for two years, then they die, so lots of the usual conservation tools are harder than usual to implement.

I believe there are a few spots where they've installed a watering system on the island to keep a few plants nicely soggy.

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Re: Biodiversity decline megathread

Post by bjn » Thu Mar 18, 2021 6:49 am

Could it be feasible to introduce a different species of cushion plant should the Macquarie Island one go extinct?

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Re: Biodiversity decline megathread

Post by Squeak » Thu Mar 18, 2021 9:11 am

bjn wrote:
Thu Mar 18, 2021 6:49 am
Could it be feasible to introduce a different species of cushion plant should the Macquarie Island one go extinct?
Tricky. There are several close subspecies but they face similar problems on other islands where rainfall patterns have changed, so they probably wouldn't help. Whether more distant relatives would survive in that super harsh environment is unclear - these guys have amazing contractile roots that stop them getting blown away and don't seem to care how many or few nutrients there are in the soil. You'd need a few centuries of growth for the new systems to establish and to find out whether they can survive and create a vaguely similar ecosystem or whether they've turned out to be the new cane toad. At least they'd probably grow slowly, so hand eradication would probably work if you really screwed things up.

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Re: Biodiversity decline megathread

Post by bmforre » Thu Mar 18, 2021 2:40 pm

Squeak wrote:
Thu Mar 18, 2021 9:11 am
bjn wrote:
Thu Mar 18, 2021 6:49 am
Could it be feasible to introduce a different species of cushion plant should the Macquarie Island one go extinct?
Tricky. There are several close subspecies but they face similar problems on other islands where rainfall patterns have changed, so they probably wouldn't help. Whether more distant relatives would survive in that super harsh environment is unclear - these guys have amazing contractile roots that stop them getting blown away and don't seem to care how many or few nutrients there are in the soil. You'd need a few centuries of growth for the new systems to establish and to find out whether they can survive and create a vaguely similar ecosystem or whether they've turned out to be the new cane toad. At least they'd probably grow slowly, so hand eradication would probably work if you really screwed things up.
Could you get Elon Musk interested in this as part of a program to found new life on Mars? Plants able to cling on in harsh conditions might be useful - not least for getting financing?

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Re: Biodiversity decline megathread

Post by Squeak » Thu Mar 18, 2021 10:09 pm

bmforre wrote:
Thu Mar 18, 2021 2:40 pm
Squeak wrote:
Thu Mar 18, 2021 9:11 am
bjn wrote:
Thu Mar 18, 2021 6:49 am
Could it be feasible to introduce a different species of cushion plant should the Macquarie Island one go extinct?
Tricky. There are several close subspecies but they face similar problems on other islands where rainfall patterns have changed, so they probably wouldn't help. Whether more distant relatives would survive in that super harsh environment is unclear - these guys have amazing contractile roots that stop them getting blown away and don't seem to care how many or few nutrients there are in the soil. You'd need a few centuries of growth for the new systems to establish and to find out whether they can survive and create a vaguely similar ecosystem or whether they've turned out to be the new cane toad. At least they'd probably grow slowly, so hand eradication would probably work if you really screwed things up.
Could you get Elon Musk interested in this as part of a program to found new life on Mars? Plants able to cling on in harsh conditions might be useful - not least for getting financing?
I could see the genetics of the contractile roots having some kind of cool applications. They work because there are X-shaped fibres down the length of the root, so when the root is well-hydrated and nourished, those Xes fatten up, dragging the plant down into the soil. It's quite a clever mechanism that ought to be either manually engineerable or genetically identifiable and copyable.

However, I somehow doubt the subantarctic ecological community would be super-keen on a Musk-approach to conservation in an environment where we are desperately trying to unpick the damage caused by two centuries of thoughtless introductions (rabbits, rats, carnivorous mice, cows, deer, cats, wekas, any number of weeds, etc). :/

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Re: Biodiversity decline megathread

Post by Bird on a Fire » Wed Apr 14, 2021 10:54 am

Who's chopping down tropical forests, then? Turns out a lot of it is because of us:
Key findings from the report:

The EU is the second biggest importer of deforestation after China. In 2017, the EU was responsible for 16% of deforestation associated with international trade, totalling 203,000 hectares and 116 million tonnes of CO₂. The EU was surpassed by China (24%) but outranked India (9%), the United States (7%) and Japan (5%).
Between 2005-2017, soy, palm oil and beef were the commodities with the largest embedded tropical deforestation imported into the EU, followed by wood products, cocoa and coffee.
During this period, the largest EU economies – Germany, Italy, Spain, the UK, the Netherlands, France, Belgium and Poland – were responsible for 80% of the EU’s embedded deforestation through their use and consumption of forest-risk commodities.
EU demand for these commodities is also driving destruction in non-forest ecosystems, such as grasslands or wetlands. The report establishes clear links between EU consumption, particularly of soy and beef, and the conversion of grassland landscapes, such as the “deforestation hotspots” of the Cerrado in Brazil and the Chaco in Argentina and Paraguay. (These were also identified in WWF’s recent Deforestation Fronts report).
https://www.wwf.eu/?uNewsID=2831941


In particular, it's beef:
Beef production is the top driver of deforestation in the world’s tropical forests. The forest conversion it generates more than doubles that generated by the production of soy, palm oil, and wood products (the second, third, and fourth biggest drivers) combined. Beef also drives conversion of non-forest landscapes, from grasslands to savannas.
(bare in mind that most soy production is to provide fodder for beef)


Converting that deforestation into carbon terms:
The three highest-emitting regions (Latin America, Southeast Asia and sub-Saharan Africa) dominate global emissions growth from 1961 to 2017, driven by rapid and extensive growth of agricultural production and related land-use change. In addition, disproportionate emissions are related to certain products: beef and a few other red meats supply only 1 per cent of calories worldwide, but account for 25 per cent of all land-use emissions.
https://www.nature.com/articles/s41586-020-03138-y
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Re: Biodiversity decline megathread

Post by Bird on a Fire » Thu Apr 15, 2021 1:11 pm

Examples of declines are so widespread, we might as well ask which bits of biodiversity aren't f.cked.

New paper in Frontiers in Forests and Global Change does just that, asking Where Might We Find Ecologically Intact Communities? The answers is, um, not super inspiring:
The vast majority of land on Earth — a staggering 97 percent — no longer qualifies as ecologically intact, according to a sweeping survey of Earth’s ecosystems. Over the last 500 years, too many species have been lost, or their numbers reduced, researchers report April 15 in Frontiers in Forests and Global Change.

Of the few fully intact ecosystems, only about 11 percent fall within existing protected areas, the researchers found. Much of this pristine habitat exists in northern latitudes, in Canada’s boreal forests or Greenland’s tundra, which aren’t bursting with biodiversity. But chunks of the species-rich rainforests of the Amazon, Congo and Indonesia also remain intact.
Summary at https://www.sciencenews.org/article/ear ... ct-species
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