Synanthropic Californian lichens

Hello iNat community,

recently I have taken an interest in the non-axenic cultivation of synanthropic lichens. While I have located a number of interesting papers on Researchgate, I have been unable to locate any outdoor specimens except for several yellow/orange dot clusters (I imagine these are an assorted mix of Caloplaca and Candelariella) in areas severely contaminated with hazardous vertebrate droppings. Furthermore, an Observations search in iNat for lichens of Los Angeles County (my area) did not appear to be effective, despite many listed synanthropic spp. apparently having plenty of suitable nontoxic substrate to potentially colonize in local gardens. Any tips or advice on this phenomenon? It appears that weedy dessication-tolerant mosses have claimed most of the niches for them.

Thanks in advance

Interesting question. Are you including lichen that benefit from car or cruise ship exhaust?

Yes; by “nontoxic substrate” I was referring mainly to poisonous compounds that such synanthropes were not immune to.

In my area (SW Coastal BC) there are street trees planted by the cities, many of which host lichens that handle N or SO (or both) pollution well. When air quality maps of cities are done (see Montreal for example), you can see the gradient of tolerance, and spots where no lichen appear.
If you are not seeing urban lichen then perhaps there is lack of substrate (e.g. street trees) or the trees are not old enough to have accumulated colonies, or the wrong kind of trees, or the pollution is too high beyond tolerance, or…
If there has been an air quality monitoring project near your area that may provide useful info.
Hope that helps.

Thanks again for the tips. I have a suspicion that it mainly has something to do with the notorious California aridity (we have mostly clean air and taxonomically diverse street trees), since a number of European rainy cities I visited were absolutely covered with bark and stone lichens happily sitting next to cigarette piles.

After considerable further searching, the interesting first article of this bulletin was located and appears to confirm my suspicions; I suppose the issue is resolved