Willamette Institute for Biological Control, Inc.

Articles

Hedgerows and Other Fragments of Wild Land

by Bill Denison

The fragments of wild land I have in mind are not wildernesses. They are man-created as surely as pavement, parks, or cornfields; but they are refuges and corridors for a wide spectrum of species. They represent the diversity we only vaguely understand t o be essential; the unsupervised patches that m ankind disdains to foster.

I am thinking not only of the shrubby, weedy hedgerows that once divided one tamed farm field from the next, but vacant urban and suburban lots, unkempt industrial fringes, and riparian zones.

These fragments are homes to the homeless of all kinds; to the poor, the independent, and the wild. As such, they threaten our perception of control, our sense of order. Creatures don't reside here, they lurk. We tolerate them for the time being, but we'll clean them up when we get around to it.

These fragments of nature may be perilous, but they are at least equally advantageous. What are the dangers and the benefits found in hedgerows and other fragments of wild land?

Dangers

Weeds. Weedy plants, adapted to man-disturbed habitats, are a nuisance; they compete with our useful plants; and they harbor pest insects, fungi, and viruses that afflict our crops. Weeds shed their unwanted seeds into our neat lawns and fields. Disease fungi, destroyed on crop residues by burning or tillage, survive the winter on weeds in hedgerows to attack another year.

Vermin. Rats and mice, annoying in themselves, are potentially dangerous as vectors of fleas and lice, and through them, of human diseases such as plague and typhus. Crows, blackbirds, starlings, sparrows and pigeons: these non-game, non-songbird, statusless creatures annoy and harbor disease.

Insects. Insects that afflict our crops, and perhaps also mosquitoes that both annoy and carry disease, are among the residents harbored in wild fragments of land.

Benefits

Weeds. Many weeds were once cultivated crops. Some still are: Queen Ann's Lace is the wild ancestor of carrot; pigweed is a cereal crop in some cultures and may be again in ours.

True, weeds harbor plant diseases and insects, but they survive. That survival is evidence of their ability to resist the attacks of pest and disease - of hearty characteristics that are genuinely irreproducable and of untold value in future scenarios. Weeds have already contributed their genetic resistance to crop disease. For example, much of the resistance to Potatoe Late Blight (cause of the Irish potato famine) was bread into potato from a weedy relative, Solanum demissum.

Vermin. Wouldn't the world be better off without the Norway Rat and the House Mouse? But vacant lots do not create rats and mice; the presence of garbage does. Clean up your act and the rats and mice will diminish; not extinguish, but largely disappear. Besides, we do not want them to go altogether. They test the benefits fo new medicines and the hazards of new poisons.

Crows and sparrows may take a significant toll of our crops. But they are also important agents of biological control, consuming tons of insects per year. The Chinese found out. They organized a great sparrow hunt in their fields, then lost much more to insects than they had saved from the birds.

Insects. Insects prey on other insects. Spiders are an important factor in the balancing act of insect populations. Insects are also subject to diseases and parasites. All these and more are harbored in hedgerows and wild fragments. The cost of harboring pest insects is more than redeemed by the benefit of the refuge provided to enemies of pest insects.

Wildlife. Game animals including pheasant, rabbit, quail, deer; other wildlife such as fox, raccoon, skunk, possum, squirrels, mice and others that are part of our heritage; songbirds that are, incidentaly, protected by international treaty, not state or federal law; all depend on hedgerows and wild fragments. The Red Tailed Hawks seen perched along Willamette Valley stretches of I-5 do so because it is the only untilled stretch containing the field mice and gophers they need to survive.

Other benefits. Hedgerows provide protection from wind erosion. Can we forget the lessons of the 30's Dustbowl now being imitated by the drought and soil loss in the mid-west? Hedgerows provide noise abatement. Hedgerows between home and highway cut noise to livable levels, even in suburbia. Hedgerows provide security. A well placed blackberry bramble is an excellent dissuasion for passers-by who may or may not notice the garden crops, or other valuables on the other side. Hedgerows provide visual relief. Beauty is in the eye of the beholder, but almost everyone prefers hedgerows, woodlots, and tree-lined streams to unrelieved square miles of tillage.

Of all the benefits, perhaps the most important is the unknown benefit of biological diversity. Who among us is wise enough to predict what new synthesis of understanding will emerge in the future? The scenarios are unimaginable, but everything we now know points to the immense value of the unsupervised, perhaps disdained, wildness of hedgerows and other fragments of wild land.

What is needed is a statewide effort to protect, enhance, and integrate these areas into the mainstream of agricultural, forestry, and wildlife management strategies coordinated with the activities of public utilities and highway systems.



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