Mycorrhizal hotspots

[adampembs]

We walked an area of birch at the side of the main road, perhaps 50metres long by 30metres wide, and found 4-5 mycorrhizal species within 20 minutes, and the same last year. We then went to the county’s largest area of ancient oak woodland, spent two hours there walking a few miles and found 2 species.

I’ve noticed this in several places, you can walk for hours and find nothing, then find a patch with lots.

Does anyone know of any work done on this phenomenom? Or have theories why they exist?

[Chris Yeates]

Too many variables Adam

don’t forget, you’re not spotting species, merely those species fruiting due to favourable conditions. The minute people start collecting the actual VAM affected roots and culturing / sequencing them they can find lots of species. I think I’ve heard that in Kew Gardens (and elsewhere) there are a lot of exotic fungi (associated with exotic trees) which have never “occurred” in this country but are effectively here . . . .

cheers

Chris

[adampembs]

Chris Yeates wrote:

Too many variables Adam

don’t forget, you’re not spotting species, merely those species fruiting due to favourable conditions.

cheers

Chris

Sure, its a purely human perception as to “hotspot” , but perhaps there are triggers to fruiting in those spots. Perhaps in the centre of a ancient wood, the fungus has reached saturation, so only fruits at boundaries. Or maybe a young wood with several intermingled tree species caused a lot of competition not only between the trees but also among the fungi. I’m guessing…

[roy betts]

Was the ground equally as wet? Perhaps the rain managed to penetrate the Birch stand and not the canopy in the centre of the wood.

[mollisia]

Hello,

I remember that Prof. Moser talked to me once about this phenomen and he had the idea that it may be that a fruiting mycelium might influence surrounding mycelia to fruit. I’m not sure how serious this was ment, at least he didn’t publish that theorie as far as I know. But the idea, that a fruiting mycelium produces certain substances that may be influencing neighbouring mycelia is not too impossible in my opinion.

I had the same phenomen last week with my course, when we (= 15 persons) walked for one and a half hour in a completely fungus-free beech forest, which usually has plenty of Russula species in that time, and we only found three species in some 10 fruitbodies – all under the same beech tree! No idea what was so special in this very spot in the forest, it was all looking the same ecologically ….

best regards,

Andreas

[adampembs]

If memory serves, there is also a tendency for the mycelium to fruit in rings as it grows further from a tree. Perhaps when the mycelium is very old and encompasses a patch of forest, with many trees, it “knows” it is less effective to produce fruit bodies in the centre, so perhaps these hotspots are at the edge of the mycelium, say at a natural barrier or where it encounters the mycelium of a competing fungus. Therefore both species fruit to try to find good “root real estate.”

[Leif]

I’ve noticed this too, there are places that routinely have a more abundant harvest than other places. I can think of two areas that are good during otherwise barren periods. I imagine that changes in the underlying geology and soil could quite easily have a large impact on the amount of available water, for example, and the nature of the soil and rock does significantly influence the fauna. As I am sure you know, some plants favour acid soil, whilst others require alkaline soil. Also many fungi are symbionts, and poor soil might perhaps lead to an increase in certain kinds of fungi that help plants compensate for the low level of certain nutrients. I know one area that is very good for rare spine fungi and Lyophyllum species, but walk 20m and they are gone. So it might be that factors that are invisible to us influence the plants and fungi.

[Gaby]

Interesting theory about one fruiting mycelium inducing competitive fruiting by other mycelia (if I understood correctly). I look for Russula as “proof of life” in pine forests, for instance: usually there are several other kinds of fungi in the vicinity.

[Author]

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