Nov 28, 2009

Let us now praise crane flies

The humble crane fly comes in many sizes, with hundreds of species in the Southern Appalachians, but there is little superlative about them. They are leggy creatures, and the largest can span about three inches. These are often called "mosquito hawks" under the mistaken notion that they hunt mosquitoes. While they resemble mosquitoes, they are entirely harmless to people and to pretty much everything.
They are the living embodiment of harmlessness, spending most of their life as a worm-like larva that eats muck and goo. Many are aquatic during their larval stage, but anywhere there is moisture and detritus there is probably a crane fly larva turning the mud and slime into something more useful: food for dragonflies, salamanders, fish, birds and all the things that eat crane flies.
Their primary defense is being inconspicuous, whether oozing through mud or in flight as adults. They are slow and quiet fliers, never buzzing like a mosquito, and their long legs afford protection. Often the tip of a leg will make first contact with a spider web, allowing them to fly away before becoming entangled. Some are so sensitive and delicate they use spider silk as a perch, hanging from strands unnoticed by the spider. Others perch on rootlets or hang on the shady side of a leaf. When they find a perch they will hang still and wait for other crane flies to find them. Any damp, shady spot might host a cluster of crane flies.
Should they get attacked, they often lose only a leg. I've seen them soldiering on with as few as three legs. As adults their goal is to mate and deposit eggs where their larvae can thrive, but eventually crane flies will be eaten.
There is a whole family, Trichoceridae or winter crane flies, that emerge during winter months. Five species occur in our area. They can freeze and will become active whenever the sun warms them. You can find congregations dancing in a sunbeam on winter afternoons. They are one of the reasons phoebes and bluebirds overwinter with us rather than retreating to warmer climes.

Nov 24, 2009

Grousing for a pardon

In a smart play on the tradition of a Thanksgiving turkey receiving a Presidential pardon, the Western Grouse Project is requesting that President Obama pardon endangered and threatened grouse in the American West. Prairies are neglected within our system of national parks and forests. The few grasslands in public ownership receive inadequate management from the Bureau of Land Management, and prairie ecosystems suffer losses of diversity as a result.
Grouse are an emblematic component of these ecosystems, and protecting them also means protecting plants, rodents and other creatures that share their habitats. The Gunnison Sage Grouse of Colorado and Utah is among our most endangered birds, with an estimated 4,000 individuals remaining. The Mono Basin Sage Grouse is a genetically distinct population along the California-Nevada border, and the federal government will issue a decision next year on whether to list those populations and the more widely distributed Greater Sage Grouse as threatened or endangered.
All these birds deserve protection, and we need to set aside more sagebrush and prairie for wilderness and conservation purposes. With better land management, these birds ought to rebound toward their historical abundance, at which time they can be delisted and treated as game birds.

Nov 23, 2009

Science is Wrong: Yellow-breasted chat

Cornell Lab of Ornithology calls it "our largest wood-warbler." "Arguably our most distinctive wood-warbler" says David Sibley. Descriptions of the yellow-breasted chat inevitably mention its exceptional traits in the first breath. It's scientific name, Icteria virens, suggests it is an oriole, and ornithologists have hypothesized it may actually belong with tanagers, vireos or thrashers, yet it is considered a warbler.
I spent an afternoon in the library while in graduate school trying to learn why the chat is a warbler, and the only conclusion I could draw is that a respected scholar put it there decades ago, and no one has had the guts to overrule him. Sometimes science works that way, especially in biology with charismatic objects of study.
Phylogeny, the study of relationships among living things, is more of a historical discipline constrained by science than a pure science. Data is usually limited by extinctions or more mundane factors, and there is an art to choosing which sets of species to compare.
It is also important to choose the right traits. Variable traits like color and size can be deceptive, and usually you need more of a gestalt that may be hard to capture in numbers. Often researchers work with museum skins, pinned or voucher specimens, so the character of the living plant or animal can be obscure. I suspect the authority who called the chat a warbler was working mainly with dead specimens.
Live chats have a whole suite of behaviors that are uncharacteristic of warblers but fit right in with mimic thrushes. Their voice is quite similar to a catbird's, and like those and mockingbirds and thrashers, they do aerial dances above their nest. Such traits are less likely to be similar due to convergence than color. Many different kinds of birds migrate. Chats seem to have been classified as warblers because they are yellow and migrate. That's just wrong.
One of these days someone is going to use molecular data to prove that chats are mimic thrushes. That's one of my benchmarks for knowing when molecular phylogeny has matured from art and bullshit to real science.

Nov 18, 2009

Fall pollinator

November seems late for flowers and bees, but a few hardy specimens stay active throughout fall. New England aster produces flowers even after most plants have shed leaves and withdrawn their life force underground.

Underground is where halictid bees nest. An underground burrow offers protection from cold, especially as falling leaves blanket the ground. 56 species in eight genera are known in Great Smoky Mountains National Park, and I'm not sure which species this is. You need to examine wing veins and subtle features of the head and legs to tell them apart, though occurrence in mid November could be diagnostic.

These bees, important pollinators of many native plants, come in greens, oranges, blues and blacks. Often their color varies with the angle of light, and this one shimmered with both green and orange. Most halictids are solitary, but others are social, cooperatively building and provisioning nests. They are a favorite object of study among biologists hoping to understand the evolution of sociality in insects. Whether working alone or together, these bees gather pollen and store it underground. They lay one or more eggs in a burrow, seal it for protection and when the egg hatches, the larva consumes the pollen to fuel its growth to adult form.

Asters are usually white, but fall blossoms often carry a hint of purple. With so few plants flowering in November, asters are often busy with insect activity. Green and black bees were visiting this plant, and a couple types of nectar-sipping flies also made appearances. Flowering witch hazels were also abuzz with visitors. As diverse as Southern Appalachian forests are, some living thing is taking advantage of any niche and any opportunity, including the sunny weeks between when leafy shade fades and winter takes it grip.

Nov 16, 2009

Ida flooding

El Nino conditions in the Pacific inhibited tropical storm formation in the Atlantic this year, resulting in a mild hurricane season. Upper elevation winds always flow from the Pacific to the Atlantic, and in El Nino years these winds are stronger than usual. They shear the tops of Atlantic storm systems, disrupting circulation and dissipating energy, so fewer storms form, and the ones that do are not as strong as they would be otherwise.
The remnants of Hurricane Ida caused record storm surges this weekend on the Virginia coast and dropped up to 10 inches of rain on coastal North Carolina. This is a reminder that warming oceans are still imparting considerable energy to storms. Ida began in the southern Gulf of Mexico, traversed the entire gulf, crossed Florida and still had enough power to push nearly six feet of water onto Virginia beaches.
As Weather Underground meteorologist Jeff Masters points out, the combination of coastal subsidence and rising sea level means that today's surges are a foot higher relative to the land than storms in the 1930s that produced similar swells. At the same time climate change is generating more and stronger storms, coastal areas are growing more vulnerable to damage.
Masters also asks his readers to sign a letter to the White House asking for funding to replace a failing weather satellite, QuikSCAT, that has proven invaluable to weather forecasters. I signed it. It just takes a few seconds, please join me.

Nov 15, 2009

Laurel Falls

When Clarence Darrow squared off against William Jennings Bryan in the Scopes trial in Dayton, Tenn. 85 years ago, both attorneys likely drank water from Richland Creek. The town's water supply once flowed out of a reservoir just below the confluence with Laurel Creek. The one-foot-diameter pipe still runs along the creek, broken in places and no longer connected to the small dam.
Running through a narrow gorge it has carved into the eastern escarpment of the Cumberland Plateau, Richland Creek now provides recreation to Dayton residents and visitors. Boulders define the creekbed, creating deep swimming holes and fast-flowing chutes that attract kayakers. The deep gorge is shaded in morning and afternoon, but midday you can swim in the cold, clean water and drip dry in sunshine.
On a November afternoon, boulders were drenched in dry leaves as much as sunshine, with only beeches and sweetgums holding their colors in the nearly bare forest. Witch hazel and pale purple asters were flowering, a final feast for a few species of bees and hover flies. Hardy crane fly orchids poked new leaves through the layer of fallen leaves, rich purple yielding to a papery green as they matured. They generate energy from the unshaded winter sun and next summer will send up stalks of gangly flowers for which they are named.
From the 80-foot descent of Laurel Falls until it joins Richland Creek, Laurel Creek tumbles through boulders and across exposed layers of rock laid down when the plateau was a seabed. Mostly sandstone, the rocks sometimes include nuggets of quartz and pebbles. At the junction of the two creeks is a broad boulder field and a few campsites for backpackers. The land was once owned by paper manufacturer Bowater but was given to the state a few years ago and is now part of Cumberland Trail State Park.

For more photos, visit my album on Facebook.

Nov 12, 2009

A natural fit

Follow the link in the title of this post to my latest column in Metro Pulse. I propose a natural history museum in Knox County, capitalizing on the role of the Southern Appalachians in the evolution of terrestrial life. State leaders convened in Knoxville this week to lament Tennessee's lagging education system, and development of a major educational asset like this would be a step toward a better future.

Nov 11, 2009

Oaken browns

looking up into a white oak

Experts in fall colors say heavy rains just before the leaves turn result in less spectacular colors. Maples seem consistently spectacular, especially sugar maples, and burgundy trees like dogwoods and sourwoods seem the same each year. Hickories have a few days of brilliant gold, and maybe they linger at peak color longer in drier years. The type of tree that varies most year to year is oaks.
This fall the oaks were brown. I saw one red oak that was truly red, the exception that confirmed my impression. I dug through fall photos taken last year, and I offer this one as proof. It's a white oak near my house, and it was never as pretty this year as it is in this picture.

Underbilling for overflows

The Environmental Protection Agency fined Knoxville Utilities Board $68,050 for sewage overflows over the past four years. This is a minuscule fine, less than two cents per year per customer, surely inadequate to cover EPA's expense in monitoring KUB's system and Knoxville's creeks. It's acceptable, however, because KUB has committed to upgrades that will cost about $120 per customer per year and hopefully bring an end sewage spills into backyards and streams. Halfway through the 10-year program, KUB is reporting a 70 percent reduction in overflows.
Less sewage in our waterways means more life, from crayfish to minnows to birds. It means fewer annoying insects like mosquitoes and flies and more interesting ones like mayflies and dragonflies. It means less worry about touching the water or eating fish and less slime on the rocks. This adds up to healthier recreation, better quality of life and higher property values. So our investment as ratepayers and as taxpayers supporting EPA is yielding long-term value for the community.

Nov 10, 2009

Merida Message

International conservation groups meeting in Merida, Mexico this week have released the Merida Message: "runaway carbon emissions are driving the climate towards irreversible tipping points, we are contaminating our planet with pervasive toxicity, destroying the diversity of life on our planet, exhausting freshwater supplies and causing acidification in our oceans, and over-exploiting our oceans, causing fisheries to collapse. As a result, we are deepening poverty, weakening social structures and threatening global security. This situation is in stark contrast to the world we can have if wilderness and its contribution to natural life support systems are properly valued and protected. Wilderness sustains us, generating the essential services that make possible our economic and social prosperity, our physical health and our spiritual well-being. Our essential choice - indeed, the imperative - has never been clearer.

This statement underscores a persistent problem with the modern economy, an imbalance between short-term and long-term value. Geared toward perpetual growth and quarterly profits, our economy is drastically distorted toward short-term gains. As the current economic crisis proves, financial titans are willing to take huge risks, and they have gamed the system to immunize themselves from harm. They play with everyone's retirement savings so they become "too big to fail." More critically, an economy focused on growth rather than sustainability risks squandering resources that will be worth much more to future generations than to us. We destroy wealth by discounting the long-term value of resources we exploit.

Nov 9, 2009

Climbing fern

Climbing fern is an unusual fern found in the higher elevations of East Tennessee. It grows like a vine, draping itself over other vegetation, but it is a fern. Ferns do not have woody stems. This plant actually produces very long fronds with leaflets every couple inches. The texture of the leaflets makes it apparent that this is a fern and not a woody plant. The stems are thin, more suggestive of tendrils than vines, and the plant has a delicate, lacy posture.

Fronds grow reproductive structures near their tips, and these have the same shape as the leaflets, but in miniature. Spore-producing organs form on the underside of these fertile leaflets.

This photograph was taken on the Obed River segment of the Cumberland Trail. American climbing fern (Lygodium palmatum) occurs throughout the Cumberland Plateau and is less common in the Smokies. Northern populations have squared-off leaflets different from the round-tipped leaflets seen here. There are also distinct coastal populations on the Atlantic and Gulf of Mexico. I wonder if anyone has studied whether we have more than one species.

There is a Japanese species of climbing fern sold as an ornamental, and an Asian species has invaded Florida, causing major problems in the Everglades. Stem-boring moths are being tested as potential biocontrols. I hope they are testing whether the moths pose a threat to native climbing ferns, though the distribution suggests they would have a difficult time spreading northward.

Nov 3, 2009

conformist collapse

Recessions and depressions can have natural causes -- a real event like a drought or hurricane -- or human causes like excessive risk taking and fraud. After watching William Black speak at UCLA, I am more convinced than ever that our current economic crisis is largely the result of conformist behavior. Sure, there was fraud, lots of it in layers, but what transformed an esoteric corner of the financial world -- bonds derived from mortgages and credit contracts -- into a black hole capable of sucking in the real estate and banking industries was simple conformity.

As a glance at modern television programming confirms, our nation grows more immature each year, and this economic crisis was pure high school. The student government changed the rules so rich kids could sell their lunches. They had but one lunch to sell, so they hired some nerds to build a machine that mixed their sandwiches with cheap sandwiches and wrapped them in fancy packaging. The cheerleaders said it was the greatest thing since sliced bread, and there was more to go around. Pretty soon the dope dealer started spiking the cheap sandwiches, and everyone got hooked. The price went up, and anyone who said it tasted funny got ridiculed. When the dope dealer got busted, the whole school went into withdrawal. It was neither tragedy nor swindle so much as mass foolishness fueled by mundane manipulations.

That's the allegory. As I get the chance, I will translate the tale and show that there were really only two chances to avoid the mess: integrity of the nerds or government that refuses to do the bidding of the rich. Conformists always depend on someone else's honesty. That's a great way to get fooled.