Evotour, Part Six. Fire and Renewal in the California Mountains

Cuyamaca Rancho State Park in California used to have meadows surrounded by pines and black oaks. The pines and oaks extended partway up Stonewall Peak. But in 2003, a fire burned the entire area except some places around the meadow. Today, that meadow is the only place you can find pines and black oaks.

However, the chaparral shrubs have grown back profusely. I am accustomed to dry chaparral that consists mostly of dead sticks, but this chaparral was filled with fresh green stems, flowers, and fruits. Along with the profuse regrowth of manzanita, ceanothus, scrub oaks, and holly-leaved cherry, there were perennial wildflowers in full bloom: penstemon and yerba santa. The shrubs had grown over three meters tall and state park personnel, the few that remain after budget cuts, have to keep trimming them away from the trail. A few of the black oaks have resprouted, and a few pine seedlings have been replanted.

This is a theme I have presented before, but I enjoy being reminded of it when I see it again in the natural world. Ecological disturbances, such as fires, are disasters for the organisms killed by them, but act as a source of renewal for the ecosystem as a whole. Dead grass and wood are transformed into fertilizer that feeds the vigorous growth of new plants, either resprouts or seedlings. The chaparral in Cuyamaca, and the tallgrass prairie of the Midwest, depend on a fire cycle.

I do not doubt that my hike at Cuyamaca would have been prettier if the pines and black oaks had been intact, but I would not have seen the way organisms capitalize on natural disturbances as an opportunity for renewal.

A Statement of Respect

This morning, my colleague from graduate school, Art Zangerl, died after a long battle with cancer. He personified what it means to be a dedicated scientist. He had a zeal for using science to understand not just his own area of study (coevolution of insects and herbivores) but the whole human experience of the world. I remember him doing research while we were still graduate students; he would nearly run from one room to another, carrying electrophoresis gels. This was a new technology back then, and Art studied the PGI locus to understand population variability in weeds. He was never afraid to embrace new technology, while not discarding the old. I remember him sitting at a calculator that was the size of a small table, a Wang, which used a cassette tape to store its calculation. This was long after calculators were hand-held. He also had a passion for studying things (such as invasive weeds) that had an important effect on the human economy. He worked with May Berenbaum, who may be the most famous entomologist in the world. Among other things, they studied photophytodermatitis (or is it phytophotodermatitis?) caused by wild parsnips. Everyone respected, admired, and loved Art.

In the photo posted above, taken about 1981, Art (behind the equipment) and Mark Boudreau (who is now a professor of sustainable agriculture) were using an infra-red gas analyzer to measure photosynthesis. You can see that it was a home-made apparatus, and Art was a major contributor to its construction.

Art’s wife posted his final message online right after his passing. One of the things that he regretted seeing in our society today was the large number of people who attack science general and evolution in particular in the name of religion. He wrote, “Evolution is like a magic key. Once you understand it, really understand it, so much becomes clear.” He said that evolution helps us understand the darker side of human nature, but also what he called the social side, such as altruism. Although evolution has made us a species capable of hatred, we are also a species that can fight against hatred and oppression. Art particularly admired the work of the Southern Poverty Law Center.

I hope that I can leave behind as good a legacy of honest intellectual inquiry and genuine human warmth as Art Zangerl.