Tinkering With Extinction

I am known as ‘the weed man’ or ‘the bug man’ due to my near-obsession with noxious weeds and my purchases of insects (often at the cost of a dollar per insect) to release as a controlling agent in my battle against exotics. I often write letters to the county and to adjacent landowners to either chide them or inform them of an infestation. People sometimes bring weed specimens to me so I can identify them. Everywhere I go during the warm months I leave behind a trail of uprooted invaders.
The insects are the latest and probably most hopeful agent in our now constant war one invading species. More and more, scientists are coming to understand that our burgeoning problems with weeds may only be controlled with biological mechanisms, by importing into this country some of the insects and bacteria and fungi that are natural enemies where the exotic originated. I have, in recent years, purchased moths that subsist by eating only the roots of certain knapweeds, beetles that eat knapweed flowerheads, beetles that attack only the flowerheads of dalmatian toadflax. Most all the species of insects available are host specific. Furthermore, some weeds—toadflax, knapweed, and leafy spurge—have so overtaken the landscapes out West they are considered the greatest threat to both the lanscape and the agrarian economy.
I am not simply being alarmist on this. At present, Montana has somewhere between four and six million acres infested with knapweed. Leafy spurge and toadflax are running up along the flanks. Throughout history we have seen, once they are somehow introduced, exotic and invasive species crashing through our paradise time and time again—plants, animals, and disease alike. Consider the impact of smallpox on the Native American populations. Whole tribes were ravaged once the Old World settlers introduced the disease into the “biologically naive” New World population. The Algonquin population plummeted from 30,000 to 300. Some estimates put the loss of Mexico’s natives due to the smallpox epidemic at nearly seventy-five percent. Closer to home, the Mandan population fell to a mere thirty-one survivors following a three-year epidemic that ended in 1840. A startling ninety-eight percent of infected Plains Indians perished.
Consider, also, how the accidentally introduced brown tree snake is currently liquidating the bird and rodent populations of several islands where no natural predator exists to hold the serpent numbers in check. Even the kindly frog and rabbit have devastated lands when they abruptly appeared without natural enemies to hold their numbers down. Here in Montana, the introduction of fresh water shrimp into Flathead Lake (from stock gathered in the Great Lakes) virtually wiped-out the entire salmon fishery. The shrimp, ironically enough, were meant to be a food supplement for the fish. Instead, they began competing with them. Montana has recently seen whirling disease run rampant through our legendary river and stream trout populations. And now a tiny snail from New Zealand is infesting some waters, out-competing the food species required by our fish. The fish will starve to death eating the plentiful snails because their shell is indigestible and protects the soft lout inside. Like Jonah in the Bible, most snails survive being swallowed by the fish.
A glance outside your window as you drive just about anywhere through our state will reveal how severe our noxious weed problem has become. The weeds have altered the handsome face of our state, promoted erosion, replaced our blonde fall grasses with grotesque brown tangles, usurped the forage desired by both domestic and game species.Some scientists fear we are on the verge of mass, worldwide extinctions of unprecedented rapidity—one that is now taking hold of an alarming range of species, all brought about by us, by our altering of critical habitats, by our ever increasing injection of exotic species (plant, animal, insect, fungus, bacteria) into permissive environments were they thrive and over-produce without check at the expense native species. This would be the sixth “great extinction” to beset Earth, something along the lines of the Cretaceous-Tertiary event, which occurred sixty-three million years ago and left mammals walking while all the dinosaurs perished. Some earlier events are thought to have killed off over ninety percent of all life forms. I am just nutty enough to worry. The logic of all this is clear to me. You can’t take up half the space and expect all the test of the critters to maintain their numbers. A parking lot, after all, is not a forest.

--Mitchell Hegman