Thursday, October 26, 2006

Celebrating Owls at Halloween

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If you’ve ever been awakened by the call of a screech owl, you know why people associate owls with all things eerie. But as Halloween approaches, I like to take time to appreciate the creatures of the night. The biggest fans of such creatures at my house are my children, Jane and Will, and they’ve joined me today to celebrate owls.

As birds that work the night shift, owls are equipped with some fascinating adaptations that enable them to locate and capture prey in the dark.

Will, would you tell about owls’ eyes.

Will: Sure. Owls see very well in low light. Their eyes are extra large for their bodies, and their retinas are super sensitive.

Since owls can’t move their eyes up and down or side to side the way we do, they have to move their heads instead. Sometimes it looks like an owl can turn its head around in a complete circle, but they can’t go quite that far.

Rob: Jane, why don’t you talk about how owls’ hearing helps them function in the dark?

Jane: Okay. Owls possess excellent hearing, which allows them to find prey they can’t see--like a mouse scratching for food under a pile of leaves. Owls’ ears are surrounded by deep, soft feathers that can be spread to make a sound-collecting funnel. The dish shape created by the owl’s face is also thought to collect and focus sound. It’s said that an owl can hear a mouse squeak from half a mile away!

Dad, we should also tell people that an owl’s ears are openings in the side of its head. Those tufts on top of some species are display feathers, which have nothing to do with hearing.

Rob: Thanks, Jane. I would add that while owls hear very well, they are also good at not being heard as the fly. They have specially adapted flight feathers that reduce the noise made by air passing over their wings. This allows them to swoop in on prey undetected.

Will, maybe you could say more about owls as hunters.

Will: Owls use their powerful feet and sharp talons to attack and hold prey. And just about any small animal can be prey for one owl or another.

Owls eat some small animals, like insects, worms, scorpions, crayfish, frogs and snakes.

Jane: Jane again. Owls also prey on mice, rats, voles, rabbits, squirrels, and many kinds of birds. The great horned owl, which has a poor sense of smell, even makes a habit of eating skunks.

You can tell what owls have eaten because they cough up pellets containing fur, bones, and other material they can’t digest.

Rob: One way to find owls during the day is to look for these pellets and for large splashes of owl whitewash at the base of trees, especially evergreens, and then look up.

Will: Or maybe you’d rather enjoy owls from a distance.

Jane: Listen to the great horned owl—

All: Halloween is just around the corner.

Credit for audio of owls calls to the Macauley Library at the
Cornell Lab of Ornithology
, Ithaca, New York. Special thanks to Tammy Bishop for her help!

Thursday, October 19, 2006

Local Effects of Climate Change and Screenings of An Inconvenient Truth

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Residents of the American Midwest will not witness directly the most dramatic effects of global warming in the century to come. Melting ice sheets, thawing permafrost, and enormous changes in ocean currents will greatly impact our lives, but we won’t have front row seats to watch them happen. Even so, projections by Professor Don Wuebbles and other UIUC atmospheric scientists suggest that by the year 2100 the climate of Illinois will differ greatly from what we experience today. If you’ve got plans to be around then, a visit to present day eastern Texas might be a good preview of what you’re in for.

If we do nothing to reduce the amount of carbon dioxide and other greenhouse gases we put into the atmosphere when we drive our cars and run our air conditioners, the best climate models predict a worldwide rise in average annual temperature of 2 to 11 degrees Fahrenheit by the end of this century. But climate models suggest that temperature changes in our area are likely to be more dramatic. That is, the Great Lakes region can expect a rise in average daily temperatures of 5 to 12 degrees in winter and 5 to 20 degrees in summer.

At first glance the projections for changes in precipitation over the next hundred years look a little less depressing, since current models suggest that the annual average amount of precipitation for Illinois is projected to remain more or less constant. But within that average are unfavorable changes in seasonal patterns of precipitation. Models predict an increase in average winter precipitation, and no change or a decrease in summer precipitation. This scenario leaves us with much drier conditions than we now experience, since increases in winter precipitation will not compensate for the drying effects of a warmer climate. Drier conditions, of course, mean more pressure on Midwestern aquifers and surface water, especially as it becomes necessary to irrigate corn

Evidence also suggests that Illinoisans of the twenty-second century are likely to face more frequent disruptive weather events than we do now. Projections indicate longer, more severe heat waves, both earlier and later in the season, and a greater likelihood of intense storms, including 24-hour, multi-day rains.

Of course such changes in climate would also entail complex, undesirable ecological changes too numerous to even sketch here. But if you call to mind a few of the pests that are currently kept in check by our long winter freezes—kudzu and Asian soybean rust among them—you can get a sense of the impact significantly warmer winters might have.

Am I beginning to sound like Al Gore? I guess it’s no coincidence, since it’s the return of his documentary on global warming to Champaign-Urbana that got me going on this topic.

Next week the University YMCA and the UIUC Environmental Council will host two free screenings of An Inconvenient Truth. Both screenings will take place on Tuesday, October 24th—the first at noon at the University YMCA and the second at 7:00 p.m. in the auditorium of the National Soybean Research Center [map] on Peabody Drive in Urbana. A discussion led by Bill Sullivan, Director of the UIUC Environmental Council will follow the evening screening.

On the chance that you won’t make it to the film, which is way more entertaining than you might expect, let me emphasize two of the most important points it makes. First, every reputable climate scientist in the world agrees that global warming is real, dangerous, and a result of human activity. Second, most experts agree that we can avoid the most serious consequences of global warming if we act now to reduce greenhouse emissions.

Thursday, October 12, 2006

Economic Benefits of Environmental Clean-up in Great Lakes Area

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Put yourself in the position of a policy maker trying to decide whether or not to spend tens, or maybe even hundreds of millions of dollars to clean up a polluted river or harbor on the Great Lakes. Forty three such sites have been identified, and they’re contaminated with PCBs, heavy metals, and other industrial wastes--really nasty stuff that poses a direct threat to human health and destroys or degrades aquatic life. Among the many questions you face is whether there’s an economic benefit to be realized by such an undertaking.

Well, there is.

John Braden is a professor in the U of I Department of Agricultural and Consumer Economics who has worked in recent years to quantify that benefit.

Most recently, Braden has collaborated with economists from Georgia State University and the Northeast-Midwest Institute based in Washington DC to gauge the value to local homeowners of cleaning up sites on the Buffalo River in New York and the Sheboygan River in Wisconsin.

One way Braden and colleagues sought to do that was to collect data for housing sales in both areas for the years 2002 through 2004. Their preliminary study of this data suggests that property values of single-family, owner-occupied homes are depressed significantly by the polluted state of the rivers: between one and seven percent in Sheboygan and between six and nine percent in Buffalo. In other words, a home in the Sheboygan study area that sold for a hundred thousand dollars in 2003 would more likely have sold for between a hundred-one and a hundred seven thousand dollars if the river were not so heavily polluted. Not surprisingly, the negative effect of the pollution on property values was more pronounced nearer the rivers.

Researchers also surveyed homeowners in both study areas directly about whether they would be willing to pay more for residential properties were the pollution in the rivers cleaned up. In Sheboygan, responses to the survey suggest that area residents would be willing to pay on average ten percent more for residential properties; in Buffalo that figure was fifteen percent.

From a public policy standpoint it’s worth looking at the aggregate numbers that come out of these studies. A seven percent increase in property values for the area that was studied near the Sheboygan River would translate into a $108 million dollar increase overall. A nine percent increase in property values for the Buffalo area would mean a $140 million dollar increase overall. Such increases in property values mean increased revenue for local governments, which suffer from depressed values just as citizens do. Since local governments pay a share of clean-up costs in order to obtain state and federal assistance, any revenue increase they invest in further clean up could also bring in even more state and federal help.

Braden emphasizes that the increase in property values he and his colleagues have calculated is only one of the economic benefits to be realized by an accelerated clean-up of contaminated areas around the Great Lakes. He suggests such areas would likely also enjoy great benefits as opportunities for recreation multiply and fisheries recover.

Of course good public policy does not rest on economic factors alone. In the simplest terms, we ought to clean up our own messes. But that’s not to say we can’t enjoy it when we find out that doing the right thing pays off, too.

Thursday, October 05, 2006

Rain Gardens an Elegant Way to Handle Storm Water

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Facilities & Services Rain Garden sketch

Sandy Mason's UI Extension column on Rain Gardens

Wisconsin DNR Rain Gardens How-to Manual for Homeowners (pdf file)

In a vegetable garden, you grow vegetables. In a flower garden, you grow flowers. In a rain garden you . . . . Well, unlike these others, the purpose of a rain garden isn’t limited to what grows in it. A rain garden is actually a landscape feature that functions as a small-scale, temporary wetland.

A rain garden typically consists of a shallow depression that is planted with shrubs, flowers, and grasses that are native to the region where it is located. A rain garden may be designed to receive water from a downspout or sump pump, or it may be located to intercept water that runs off of a parking lot or other impermeable surface.

Like a natural wetland, a rain garden provides important ecological services. Chief among these, it reduces the amount of water that enters streams via storm drains during and immediately following rain showers. In this way, a rain garden helps to alleviate flooding and cut down on the amount of silt and pollution that washes into our waterways. Water that is held back in a rain garden infiltrates the soil more effectively than water that runs over a lawn, and thus it can also help to recharge groundwater locally.

Also like a natural wetland, a well-designed rain garden is a pleasure to look at, and it provides a bit of wildlife habitat, albeit on a small scale. During the growing season native flowers used in a rain garden can be a magnet for butterflies and other beneficial insects. Over the winter the seeds from those flowers and the berries from shrubs can provide food to attract birds.

I should emphasize that while a rain garden functions like a wetland, it is not a pond. A rain garden should dry up following precipitation as the water it holds filters into the soil.

If you would like to see a really super rain garden in the making, check out the project on the U of I campus just south of Allen Hall on Dorner Drive. There, students enrolled in a Natural Resources and Environmental Sciences internship class are busy actually constructing a rain garden. They’re implementing a design that was produced by students from another class this past Spring. Beyond retaining and purifying stormwater, this particular rain garden is intended to alleviate ponding around a substantial red oak tree on the site, and to prevent flooding on heavily used adjacent sidewalks. Construction of the rain garden is being funded by U of I Facilities & Services in conjunction with the Environmental Council as part of a broader effort to develop and showcase sustainable practices on campus.

If you are interested in creating a rain garden of your own, you may want to start with some of the links at the Environmental Almanac website. These include a how-to column by U of I Extension educator Sandy Mason and a more detailed online manual for homeowners.

Whether at home or in larger landscapes, if your goal is to reduce storm runoff, rain gardens are an elegant, low tech, low cost, environmental solution.