Life is complicated. Soft summer days beckon and seem to hold the promise of simplicity and ease. A trip to the beach or to the mountains, or a day spent in the shade of a four hundred yer old oak or in a canoe paddling down a gentle river lulls the mind into an idyllic tranquility. Nature seems perfect peaceful and serene. But this is an illusion.
You could be, for example, a checkerspot butterfly. What a carefree life, fluttering through the paintbrush and tidy tips, the wild parsnips and owl;s clover. But if you were a checkerspot, you would be studied and followed, photographed and mapped more than any other butterfly of Earth. Your life would not be your own. And the reason for this is that there are so few of you. You are almost extinct. As a matter of fact, during dry years or droughts you seem to have vanished completely. But you persist, if only in a few places. Your life is not easy.
You live in a few choice spots in the chaotic jumble of rocks that have been twisted and turned, compressed and exploded, thrust up and dropped down to form the Coast Range and Bay Area. For the moment, cosmically speaking, this heap of rubble has come to rest in such a way that here and there along the ridges on either side of a valley now named for one of Earth’s abundant minerals–silicon–there are outcroppings of a rock known as serpentine.
Serpentine, composed primarily of the namesake mineral of the valley, is a beautiful rock. It comes in greens like jade, shot through with ripples of white. It is soft–if a rock can be– and soapy in texture. It is a rock people notice. It is a rock you would need if you were a checkerspot.
In areas where serpentine abounds, it weathers and provides a soil that is a little different from the soil found in surrounding areas. It is nutrient poor. Some flowers and grasses find this serpentine soil a little hard to take. But some plants love it. And those that do grow wildly and bloom in the spring making a scene that looks lik a painting from Paradise. And it is these plants that you would rely on for your bread and butter if you were a checkerspot.
Checkerspot larva feed on the small plantain and owl’s clover found growing on serpentine soils. The brief blooms in the spring of the serpentine plants coincide exactly with the short nectar-eating life of the checkerspot butterfly. Serpentine plants and checkerspots have a partnership that cannot be easily altered.
In spring it is not hard to see where serpentine stops at the bottom of a ridge or the crest of a hill. Abruptly a glorious scene of blooming flowers changes to one that is less lush, one in which grass predominates. Where the serpentine ends it is like leaving Paradise to return to Earth again, albeit a beautiful Earth. Recently, though, something has changed in the serpentine areas surrounding our valley. Earth is creeping into Paradise. The plants and grasses that rarely ventured in to the lean serpentine soils are encroaching, crowding out the plants that once thrived and rose to the serpentine challenge. Your neighborhood would be shrinking if you were a checkerspot.
What’s going on here? And what’s to be done? Unlikely answers have been found to both of these questions. In a word the answers ar “Cars” and “Cows”. But the connections are complex enough that they lay to rest forever the notion of simplicity in nature.
The answer to why the serpentine is now able to support plants that never grew there before lies in the emissions of exhaust gases from thousands and thousands of cars. The nitrogen compounds belched out of a hundred thousand tailpipes have created air that we can sometimes see, and these gases are not totally gone even when we cannot see them. This nitrogen has to go somewhere. It drifts with the breeze and blows with the wind that funnels down the valley to work on the mountains where serpentine soils lie benignly beneath. The nitrogen is deposited, little by little. And as surely as gardeners see changes in their plants from the nitrogen fertilizer they carefully apply, the serpentine soils are nourished. Plants and grasses that would not survive in the lean soil before, now gain a foothold and soon thrive. The owl’s clover and plantain, the tidy tips and wild parsnips, small plants used to living frugally in meager soils, are edged out and overwhelmed by more robust vegetation, foodstuffs that would be foreign to you if you were a checkerspot.
And this is where the cows come in. If just enough cattle are allowed to graze on serpentine lands, the intruders are kept in check. The intruding grasses are large and preferred by cattle. But if there are too many cattle, they will eat even the smaller less vigorous native plants, the ones the checkerspots rely on. Just enough cows, the plants and checkerspots that live on these plants continue to flourish. Too many cows, no plants at all and no checkerspots.
But checkerspots are survivors, reappearing and hanging on when once they were thought gone. Somehow in some incomprehensible way, they have claimed media attention. They are giving life their best shot. Hanging in the balance against unforeseen and unknown odds, enduring complications and complexities, they may represent for us more than a vanishing species. Life is never simple.