Enjoying Spiders

Listen to the commentary
Real Audio : MP3 download

Halloween is upon us, the one time of year people put up spider webs at home instead of taking them down. It’s also a great time to celebrate and explore some of the things that creep us out. Like spiders.

Since children are usually a little more open to these subjects than adults, I’ve enlisted the young naturalists from my house, Jane and Will, to help out with today’s show.

Let’s start with the basics. Kids, are spiders insects?

Both: Nooooo.

How can you tell?

Jane: Spiders have eight legs; insects have six.

Will: Yeah, and spiders have only two body sections; insects have three.

Jane: Besides that, all insects have antennae, and most have wings.

Will: Spiders don’t.

There are more than five hundred species of spiders found in Illinois, more than three thousand in North America. The big ones like tarantulas, orb weavers, and wolf spiders tend to get the most attention, but they represent only a small portion of the spiders all around us.

And spiders are all around us. In an often-repeated bit of wisdom, which I pass along here without scientific confirmation, you’re never more than three feet from a spider.

Spiders thrive in and around buildings, on trees, in grass, under rocks, and in caves. There’s even a spider that lives most of its life under water, using air bubbles trapped in silk to breathe.

Kids, does this mean we’re in constant spider danger?

Both: Noooooo.

Very few spiders are aggressive toward humans. When they bite people it is usually because they have become trapped next to the skin, either in clothing or bedding. This is not to say a bite from a spider can’t be serious. In Illinois, both brown recluse spiders and black widows can deliver a bite requiring medical attention. As a rule, though, people greatly overestimate the likelihood and severity of spider bites. Spider venom is meant for spider prey, which is mainly insects and other spiders.

If it creeps you out to think of how many spiders there are around you, think of how many more mosquitoes, flies, and other pests we’d have without spiders on the scene to eat some of them. Or better still, enjoy some of these cool spider facts.

Jane: Some spiders with fierce names, such as the rabid wolf spider, are really harmless to people. Others, like the black widow, live up to their names.

Will: Trapdoor spiders live in burrows underground. At night they wait by the door and spring out to capture insects passing by.

Jane: Spiders can parachute. As you may remember from Charlotte’s Web, spider young send out a balloon of silk to be carried away in the wind.

Will: A bolas spider swings a strand of webbing like a sticky tetherball to catch moths out of the air.

Is your spider sense tingling yet?

Jane: We sure hope so.

All: This year, think spiders for Halloween.

Illinois Needs Updated Water Withdrawal Law

Listen to the commentary
Real Audio : MP3 download

It’s not unusual for the Illinois Department of Natural Resources to receive calls from well-meaning citizens asking whom they should contact for a permit to take water out of a stream. The answer to this question might surprise you—it’s no one. Although there are highly developed state and federal regulations concerning what can be discharged into Illinois waterways, our state has only very old, very vague rules about taking water out of them.

According to Wayland Eheart, professor of civil and environmental engineering at the U of I, this lack of specific regulations spells trouble as the demand for surface water in our state grows. It both sets the stage for conflict among users of surface water, and threatens water quality, since the levels of pollutants allowed in wastewater discharges are calculated with reference to historical low streamflows.

The rule that applies now in Illinois is known as riparian doctrine. It allows those who own land adjoining a waterway to use a “reasonable” amount of water from it. What constitutes a reasonable amount? Riparian doctrine does not say. But in a future where the demand for surface water could outstrip supply, it would be terrible public policy to have such a fundamental question decided on a case-by-case basis in the courts.

Eheart offers the following scenario to illustrate how a shortage of surface water might come about in the not-so-distant future. Say this year’s drought is followed by another dry year, or two, or three. Under such circumstances, farmers who had not previously irrigated their crops might install irrigation equipment, which is very expensive. That means taking water from streams that are already under stress in times of severe drought. But it also creates an incentive to take water from streams even in times of moderate drought, since the highest cost associated with irrigation—buying the equipment—would already have been paid.

According to Eheart, a typical center-pivot irrigation rig covering a hundred sixty acres can consume water at roughly the same rate as a small town. This is because, by design, little of the water used for irrigation is returned to its source. In contrast, much of the water used by households and industry flows back into waterways after having been treated.

The state water withdrawal law Eheart envisions would avert conflicts between users by allocating each a percentage of the available flow in a stream, and establish priorities for types of water use in times of scarcity. Eheart emphasizes that such a law would protect all water users, including farmers. As he points out, there is nothing in current law that would prevent a factory upstream from putting a pipe into a river and effectively turning a downstream farmer’s irrigation equipment into idle scrap metal.

Eheart also envisions implementing a market for water withdrawal permits, which would allow farmers and industries needing more water to trade for permits with others needing less.

The complexities of developing new laws to govern the withdrawal of surface water in Illinois make it tempting to leave well enough alone. But if we want such laws to achieve a fair balance among the needs of all users and the needs of aquatic ecosystems, we would do well to get them enacted before conditions change for the worse.

Walking, Wellness and the Environment

Listen to the commentary
Real Audio : MP3 download

The most basic form of human locomotion, walking, gets so little respect in our culture, I sometimes wonder we don’t just forget how to do it. As a means of getting from one place to another, it’s a last resort. As a form of exercise, it’s at the bottom of the list. But recent and upcoming activities in Champaign-Urbana and on the U of I campus suggest that walking may be poised for a comeback.

Last week six elementary schools—three in Urbana and three in Champaign—marked the second local observance of International Walk to School Day. This event encourages walking to school as a way of promoting children’s health, reducing fuel consumption and air pollution, and emphasizing the need for safe routes for walking and bicycling.

Now these are all fine reasons to walk to school, but they’re a little heavy on virtue. I would emphasize in addition that it is enjoyable for children to walk to school, and a treat for parents who have the opportunity to walk with them.

The walk to and from school is a great time to enjoy listening to kids. They’re not distracted by books or tv or computers or toys. And parents who are walking with them are free to listen instead of focusing on the demands of driving. In the morning you may be reminded of the kinds of things that kids look forward to in a day, whether that’s time to work on a special project in class, free time in P. E., band, or just what’s on the menu for lunch. In the afternoon, you may find out what children have learned in class, but you’re just as likely to hear what was gross, what was funny, who was mean or nice to whom—the kinds of things that really occupy kids.

Walking to school is also a great way to enjoy the natural world, even in a relatively urban setting. After all, any walk can be a nature hike if you approach it as one. Walking to school gives kids a chance to investigate the ants that sometimes pile up around cracks in the sidewalk, it gives them time to wonder why squirrels chase each other the way they do, and it provides excellent opportunities to smash acorns, kick walnuts, or collect buckeyes.

And on top of that, walking to school is good for kids and the environment.

Of course walking also promotes wellness in adults, and beginning today the U of I is hosting a three-day conference for researchers from around the world who study the connections between walking and health.

Conference organizers also hope to engage the community with a number of “legs on” activities. Chief among these is a massive “Walk Toward Wellness” on the main quad at the U of I tomorrow, which will be led by Chancellor Richard Herman and his wife Susan. Registration for the walk will begin at 11, and the walk itself will start after an introduction by interim Provost Jesse Delia at noon.

So, if you can, walk your kids to school tomorrow, or walk on over to the quad at noon.

Ethanol and the Environment

Listen to the commentary
Real Audio : MP3 download

It would be difficult to live here in the heart of corn country and not like the idea of ethanol, the corn-based fuel that can substitute for gas in our cars. But as citizens who foot the bill for energy policy and who value a healthy environment for ourselves and our children, we have an obligation to look more closely at what we’re buying when it comes to energy alternatives. As it is currently produced, ethanol delivers far less than the hype surrounding it promises.

Marketers of ethanol term it a “renewable” resource, trading on the idea that it is simply energy captured from the sun made available for use as fuel by distilling grain into alcohol. What most people don’t realize, though, is that large quantities of fossil energy are used to grow corn, and still more is required to power the distilling process. Indeed, whether the system as a whole produces more energy than it consumes is still open to debate. In any case, even under the rosiest scenario, only a fraction of the energy available in a given quantity of ethanol can realistically be labeled “renewable.” The rest is, in effect, repackaged fossil fuel.

Ethanol has also been touted as environmentally friendly, because as an additive to gas it alters the composition of engine exhaust, reducing emissions of certain pollutants. What ethanol does not do is significantly reduce nitrogen oxides, the most important smog-causing tailpipe emission from a late-model car. The best way to reduce smog-producing tailpipe emissions is to reduce the amount of fuel cars burn in the first place.

Beyond that, if we’re going to gauge ethanol’s environmental friendliness, we really need to look past what’s coming out of our tailpipes. The true environmental costs of adopting ethanol as a fuel are in fact much broader. They include the environmental impacts of growing corn, such as habitat alteration, soil erosion, and pollution from pesticides, herbicides and fertilizers, as well as the environmental impacts of the distilling process. Ethanol plants have been very slow to adopt air pollution controls, and they use enormous quantities of water, itself a finite resource.

When we’re asked to buy the idea that ethanol represents a homegrown alternative to gas, we are also asked to buy the implication that using it can help free us from the geopolitical entanglements associated with our dependence on oil. But ethanol replaces only about two percent of the gasoline we currently use, and even greatly expanded production will not reduce our demand for oil significantly.

As in the case of air pollution, if we’re serious about reducing our dependence on oil, we can make greater strides toward that goal by adopting higher standards for fuel efficiency.

A special thanks to Walt Robinson from the Department of Atmospheric Sciences for Assistance with today’s program.