Trophic sun Cascades
peaks & valleys
l u So
the weekly
the bright side
BY DICK DORWORTH
A
ll of nature—the environment’s cornucopia of lakes, forests, rivers, oceans, mountains, meadows, deserts and plains, and the flora and fauna of local and foreign ecosystems and you and me representing humanity, just to name a few of the interlocking parts of the natural world—is affected every day by trophic cascades. It is a term and topic not without controversy, both within the scientific community and among those prone to conflating science and politics. Nevertheless, we are all well served by contemplating and trying to understand (and observe) trophic cascades in the world in which we live. Author, scientist and environmentalist Aldo Leopold (1887-1948) is credited with first describing the dynamic as early as the 1930s and ’40s in connection with his observations of wolves and the effects on the ecosystem when they were removed. Just mentioning wolves, as everyone reading this well knows, invites controversy. Perhaps if Leopold had been observing mountain pine bark beetles, sea otters, wolverines or blue-green algae and their trophic cascading relationship to the changing interactions of entire ecosystems, instead of wolves, the term ‘trophic cascades’ would rest more comfortably in popular discussions and debates about the world’s environment. Leopold literally turned ecologists’ understanding of the environment upside down. Before him, it was generally perceived that every ecosystem was regulated from the bottom up by resource availability: that is, plants at the bottom take energy from the sun; herbivores take energy from (eat) the plants; and carnivores (predators) at the top take energy from (eat) the herbivores. The food chain of nature is far more complicated than this simplistic description, of course, but Leopold noted that when wolves were removed from a particular environment the deer population increased, which in turn reduced the vegetation, which negatively affected every part of the ecosystem connected to that vegetation. That is, all of it and its regulation worked both ways—top down as well as bottom up. Brian Silliman and Christine Angelini of the Nature Education Knowledge Project describe it as, “When ecosystems are green, predators are often holding grazers in check, while, when they are overgrazed, predator loss or removal is often responsible for elevated grazer densities and plant loss. This tri-trophic interaction, where predators benefit plants by controlling grazer populations, is known as a trophic cascade.” By the early 20th century the sea otter of Southeast Alaska and the Aleutian Islands was hunted to near extinction for its pelt, called by one wholesale distributor “the most luxurious and exclusive fur in the world.” Sea urchin populations exploded as their primary predator, the sea otter, vanished, and, as a consequence, kelp beds, a staple of healthy seabed ecology in Alaska, diminished drastically. In recent years sea otters have been reintroduced to the oceans around the Aleutians and “…predictable changes in the density of sea urchins, kelp, and the organisms that utilize the habitat created by healthy kelp beds, have been observed, demonstrating the potential for whole-ecosystem recovery with the reinstatement of predator populations (Estes & Duggins 1995).” That is, trophic cascades can decimate entire ecosystems from bottom to top of the food chain, and vice-versa, and they can also reverse the damage in Dick Dorworth is a Blaine both directions and restore County resident, author and ecosystems to the dynamic bal-former world record holder ance that is a healthy natural for speed on skis. Visit his website and blog at dickdorworld. worth.com. tws Think of that. 18
Armchair Airline Captains
BY BRENNAN REGO
Air Service to and from the Wood River Valley has been an absolute breeze this year. From the efforts of organizations such as Fly Sun Valley Alliance and the Sun Valley Board of Realtors and local businesses like Sun Valley Air Club, all sorts of jets are landing at Friedman Memorial Airport these days. For the Valley’s resort-based economy, each landing in Hailey means a great deal and opens the door to endless bright possibilities. This is a poem about travel via the written word, through which a writer might transport a reader almost anywhere. It’s a poem about wordsmithing for those who enjoy playing with words.
Armchair Airline Captains BY BRENNAN REGO
Photo courtesy of Sun Valley Air Club
We are the captains of your armchair airline, Waiting to jet you on the wings of our ink To destinations of our craft’s creation Where our ideals may intersect. So sit back, relax and enjoy the flights of our fancy, And let us suspend your reality Like great illusionists On a dog-eat-dog-eared stage. We are the merrymakers ‘round your hearth-hemmed campfire And the mischief-makers in your mind. We are the window washers of brains, Who help you see more clearly what could be. We are the edge of your seat, the book-spine-tinglers, The cliffhangers, the page turners and the coveted arcs. We are the bookworm-ridden apples And the reason for your bite-tattered finger nails. We are your bedtime yarn spinsters Whose graphite needles administer Your pre-doze dose of happily ever afters, Once-upon-a-time princesses and villains most sinister. We are the dark and stormy knights, Garbed in icky, coffee-stained, thrift-store armor, Who’ll whisk you away on the clickity-CLACK Of warhorse hooves through our keyboards’ tickling. We paint scenes with thousand-to-one odds against us And conjure battle horns to sound our triumph. The best of us will rip your soul right out of your body And suture it back without a single loose thread. We are the witching hour scribblers, The pen points’ ball dribblers, Whose pigments let fly the figments of Your and our mustang imaginations. “The Bright Side” is The Weekly Sun’s positive voice by Editor Brennan Rego. Send topic ideas that celebrate life in the Wood River Valley area to brennan@theweeklysun.com.
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Photo by Sun Valley Resort, courtesy of Fly Sun Valley Alliance
Editor’s Note The Weekly Sun gladly accepts submissions of poetry, short fiction and other literature by local authors or about local topics for publication consideration. Send submissions to Editor Brennan Rego at brennan@theweeklysun.com.
T h e W e e k ly S u n •
december 24, 2014