Philadelphia Reflections

Native Habitat

Gifford Pinchot

Teddy Roosevelt's friend Gifford Pinchot is credited with starting the nature preservation movement. He became a member of the Governor's cabinet in Pennsylvania, so Pennsylvania has long been a leader in the formation of volunteer organizations to help the cause. Sometimes the best approach is to protect the environment, letting natural forces encourage the growth of butterflies and bears in a situation favorable to them. Sometimes the approach preferred has been to pass laws protecting threatened species, like the eagle or the snail darter. Sometimes education is the tool; the more people hear of these things, the more they will be enticed to assist local efforts. The direction that Derek Stedman of Chadds Ford has taken is to help organize the Habitat Resource Network of Southeast Pennsylvania.

butterfly

The thought process here is indirect and gentle, but sophisticated; one might call it typically Quaker. Volunteers are urged to create a little natural habitat in their own backyards, planting and protecting plant life of the sort found in America before the European migration. If you wait, some insects which particularly favor the antique plants in your garden will make a re-appearance, and in time higher orders like birds that particularly favor those insects, will appear. The process of watching this evolution in your own backyard can be very gratifying. To stimulate such habitats, a process of conferring Natural Habitat certification has been created. In our region, there are over three thousand certified habitats.

Of course, you have to know what you are doing. Provoking people to learn more about natural processes is the whole idea. For example, milkweed. That lowly weed is the source of the only food Monarch butterflies will eat, so if you want butterflies, you want milkweed. For some reason, perhaps this one, the Monarch is repugnant to birds, so Monarchs tend to flourish once you get them started. After which, of course, they have their strange annual migration to a particular mountain in Mexico. Perhaps milkweed has something to do with that.

Empress tree

If you plant trees and shrubs along the bank of a stream, the shade will cool the water. That attracts certain insects, which attract certain fish. If you want to fish, plant trees. And then we veer off into defending against enemies. The banks of the Schuylkill from Grey's Ferry to the Airport are lined with oriental Empress trees, with quite pretty purple blossoms in the Spring. These trees seem to date from the early 19th Century trade in porcelain (dishes of "China" ) on sailing vessels. The dishes were packed in the discarded husks of the fruit of the Empress tree, and after unpacking, floated down the Schuylkill until some of them sprouted and took root. Empress trees are certainly an improvement over the auto junkyards hidden behind them. On the other hand, Kudzu is an oriental plant that somehow got transported here, and loved what it found in our swamplands. Everywhere you look, from Louisiana to Maine, the shoreline grasslands are a sea of towering Kudzu, green in the spring, yellow in the fall. It may have been an interesting visitor at one time, nowadays it's a noxious weed. So far at least, no animals have developed a taste for Kudzu, and no one has figured out a commercial use for it. When an invasive plant of this sort gets introduced, native habitat and its dependent animal life quickly disappear. So, in this situation, nature preservation takes the form of destroying the invader.

Charles Darwin

But where is Charles Darwin in all this? The survival of the fittest would suggest that successful aggressors are generally fitter, so evolution favors the victor. Perhaps swamps are somehow better for being dominated by Kudzu, pollination might be enhanced by killer bees. At first, it might seem so, but if the climate or the environment is destined to be in constantly cycling flux, diversity of species is the characteristic most highly desired. For decades, biologists have puzzled over the surprising speed of adaptation to environmental change. Mutations and minor changes in species seem to be occurring constantly, and most of them are unsuccessful changes. But when ocean currents change, or global warming occurs, or even man-made changes in the environment alter the rules, we hope somewhere a favorable modification of some species has already occurred standing ready to take advantage of the changing environment. Total eradication of species variants, even by other species which are temporarily better adapted, is undesirable. In this view, the preservation of previously successful but now struggling species is a highly worthy project. The meek, so to speak, will someday have their turn, will someday inherit the earth. For a while.

St. Lawrence Seaway map

And finally, there are variants of the human species to consider. To be completely satisfying, a commitment to preserving "native" species in the face of aggressive new invaders must apply to our own species. Surely, a devotion to preserving little plants and insects against the relentless flux of the environment does not support a doctrine of driving out Mexican and Chinese immigrants at the first sign of their appearance, like those aggressive Asian eels plaguing the St. Lawrence Seaway?. Here, the answer is yes, and no. For the most part, invasive species are aggressive mainly because they find themselves in an environment which contains no natural enemies. If that is the case, fitting the newcomers into a peaceful equilibrium is a matter of restraining their initial invasion long enough for balance to be restored through the inevitable appearance of natural enemies. So, if we apply our little nature lessons to social and economic issues related to foreign immigration, the goal becomes one of restraining an initial influx to a number which can be comfortably integrated with native tribes and clans. In the meantime, we enjoy the hybrid vigor which flourishes from exposure to new ideas and customs.

In the medium time period, that is. For the long haul, if the immigrant tribes really do have -- not merely a numerical superiority -- a genetic superiority for this environment, perhaps we natives will just have to resign ourselves to retreating into caves.

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Originally published: Friday, March 23, 2007; most-recently modified: Wednesday, May 29, 2019