> To answer this, we used a combination of approaches. First, we conducted a global meta-analysis of studies in which researchers measured the length of fungal hyphae in local soils using microscopes. This length of hyphae per unit of soil is known as “hyphal density”, and it provides a way to quantify how much fungal network is present in a given amount of soil. We assembled data from 322 studies, representing more than 16,000 individual soil cores collected across 9 global biomes. This gave us one of the most comprehensive datasets of arbuscular mycorrhizal fungal hyphal density compiled to date, spanning ecosystems from forests and grasslands, to drylands and farms.
> We then used these observations to train a machine learning model. The model was built using dozens of geospatial environmental layers, including climate, vegetation, soils, and land use. By learning how measured hyphal density varied across these environmental conditions, the model allowed us to predict the density of AM fungal networks across Earth’s terrestrial ecosystems at a fine spatial resolution of approximately 1 km². We also used spatial uncertainty analyses, including bootstrapping, to understand where predictions were more or less certain.
This is absolutely mindblowing work! One of the best things I've ever seen on the internet. I only wish it was granular enough to help identify mother trees[0] in individual forests
Seeing California's central valley in the bottom 3% is honestly depressing. What should have one of the world's most fascinating soil ecology has been degraded by over a century of intensive agriculture and practices that are downright hostile to any living soil
Isn't it more in line with what would be the natural climate's non-irrigated state? Low density in deserts everywhere else, and super high in eg. Eastern Kansas which is far from untouched by industrial agriculture.
You can see the black zones everywhere where there's intensive agriculture.
Naturally, plants get over 80% of their phosophorus from mycorrhizal fungi. They typically exhaust the immediately available stock near their roots before they start exuding the hormones that start the mycorrhizal association. Fertilizers (phosphorus being the most common) interrupt this natural chemical handshake.
Tilling, allowing soil to go fallow with no cover crops, and heavy machinery—especially when used in combination—are also well documented to be extremely destructive to soil microbiology.
The central valley is especially heartbreaking because just a few hundred years ago it was home to Tulare Lake which was the largest freshwater lake west of the Mississippi River. It was dried up to strip native Californians of a vital source of food and lifeways (though it occasionally reappears when we get historic rainfalls).
One of the biggest problems with the central valley today is high salinity (partly due to fertilizer use). The lake used to naturally manage its salinity with halophytic flora and periodic high-water flushing
Very cool. "The resulting map is strongest in well-sampled regions, less certain where samples are sparse. Read more about mapping uncertainty here." I can't access the paper to see what countries were actually sampled. The interactive map implies/shows that large areas weren't sampled (e.g. nowhere in the British Isles). It would be helpful if the map showed the uncertainty of the resulting map, on the map somehow.
> To answer this, we used a combination of approaches. First, we conducted a global meta-analysis of studies in which researchers measured the length of fungal hyphae in local soils using microscopes. This length of hyphae per unit of soil is known as “hyphal density”, and it provides a way to quantify how much fungal network is present in a given amount of soil. We assembled data from 322 studies, representing more than 16,000 individual soil cores collected across 9 global biomes. This gave us one of the most comprehensive datasets of arbuscular mycorrhizal fungal hyphal density compiled to date, spanning ecosystems from forests and grasslands, to drylands and farms.
> We then used these observations to train a machine learning model. The model was built using dozens of geospatial environmental layers, including climate, vegetation, soils, and land use. By learning how measured hyphal density varied across these environmental conditions, the model allowed us to predict the density of AM fungal networks across Earth’s terrestrial ecosystems at a fine spatial resolution of approximately 1 km². We also used spatial uncertainty analyses, including bootstrapping, to understand where predictions were more or less certain.
This is absolutely mindblowing work! One of the best things I've ever seen on the internet. I only wish it was granular enough to help identify mother trees[0] in individual forests
[0] https://www.scientificamerican.com/article/mother-trees-are-...
Seeing California's central valley in the bottom 3% is honestly depressing. What should have one of the world's most fascinating soil ecology has been degraded by over a century of intensive agriculture and practices that are downright hostile to any living soil
Isn't it more in line with what would be the natural climate's non-irrigated state? Low density in deserts everywhere else, and super high in eg. Eastern Kansas which is far from untouched by industrial agriculture.
You can see the black zones everywhere where there's intensive agriculture.
Naturally, plants get over 80% of their phosophorus from mycorrhizal fungi. They typically exhaust the immediately available stock near their roots before they start exuding the hormones that start the mycorrhizal association. Fertilizers (phosphorus being the most common) interrupt this natural chemical handshake.
Tilling, allowing soil to go fallow with no cover crops, and heavy machinery—especially when used in combination—are also well documented to be extremely destructive to soil microbiology.
The central valley is especially heartbreaking because just a few hundred years ago it was home to Tulare Lake which was the largest freshwater lake west of the Mississippi River. It was dried up to strip native Californians of a vital source of food and lifeways (though it occasionally reappears when we get historic rainfalls).
One of the biggest problems with the central valley today is high salinity (partly due to fertilizer use). The lake used to naturally manage its salinity with halophytic flora and periodic high-water flushing
Very cool. "The resulting map is strongest in well-sampled regions, less certain where samples are sparse. Read more about mapping uncertainty here." I can't access the paper to see what countries were actually sampled. The interactive map implies/shows that large areas weren't sampled (e.g. nowhere in the British Isles). It would be helpful if the map showed the uncertainty of the resulting map, on the map somehow.
Proud to see that my home state of Florida is absolutely lit up with root fungus.
Does it correlate with human longevity?
A map without borders.
Imagine that.