On hostile ground

Only once have I been seriously embarrassed while searching for lichens. The incident took place in 1999, a more innocent time, before it became pretty much unthinkable to "wander onto" a military installation. I was poking around the perimeter of a military airfield in Cornwall, England, the inside of which, even then, was strictly "off limits." But there was no one around, and the control tower was just a smudge on the horizon. I crawled through a hole in the fence and started my survey.

Why would I take such a risk? Lichens have been intensively studied in Great Britain by an army of amateur naturalists since about 1750. In the beginning they came from the leisured class of doctors, clergymen, and the landed gentry. But soon they were joined by members of all classes: schoolteachers, gardeners, coal miners, peddlers, even a Scottish umbrella maker. In short, thousands of lichenophiles have been crisscrossing the countryside for more than 250 years.

That long history of study has created a dilemma for modern British lichenologists: how can one make one's mark in such a well-tilled field? An ability to think laterally helps. But true devotees recognize that the key to discovery lies in new habitats that are emerging all the time in unlikely places, many virtually unexplored.

The first neglected habitat I discovered was associated with the pylon towers that support high-voltage lines. The pylons are coated with zinc, and so the ground underneath them gets a highly toxic drip during rain. That keeps out most of the higher order plants, but it opens up a niche to swards of tiny lichens belonging to little known species.

Not only are such "pylon lichens" rare, but their biology is unusual in other respects as well. Instead of being slow growing, like most lichens, they can complete their life cycle in less than a year. Their natural habitat is the spoil heaps of heavy-metal mines. I spent one holiday following pylon lines across the countryside before turning to a similar niche--the ground under the galvanized crash barriers beside the British motorways. Word soon spread, and it wasn't long before my North American colleagues were recording similar species along the interstates and around other American analogues to the British sites.

Lichens can grow in such stressed places because they are made up of fungi and algae living together symbiotically: the algae supply the fungi with carbohydrates, and the fungi supply the algae with minerals and much-needed shade. When they team up that way, they can live closer to the poles, higher up in the mountains, and farther out in the deserts than other organisms can.

What is more, they can live in places that didn't even exist in the earliest days of lichen-hunting--industrial wasteland, concrete structures, tarmacs, railway lines, abandoned cars. All have proved fruitful.

The day I crawled through the fence around the airfield, it was high summer, and the air was still enough for me to hear the sound of bees droning. I was also aware of--though, as usual, indifferent to--the human activity around me, the occasional helicopter flying overhead. But a pilot must have spotted a furtive figure walking, stooping, sometimes lying prone. Before long a Land Rover full of armed guards in riot gear pulled up beside me, no doubt wary of the hammer and chisel I was clutching. I pleaded that I was just a harmless "nature watcher," pursuing my hobby. But the station commander was not amused. He gave me a dressing down, and sent me packing.

Oliver L. Gilbert is a retired lecturer from Sheffield University, England. He has been interested in botany since an early age.

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