City Creek Nature Notes – Salt Lake City

July 7, 2017

June 30th

Filed under: Black swallowtail butterflly, Cheat grass, Gambel's Oak, Starthistle — canopus56 @ 8:41 pm

Inedible insects and plants – a war

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Caterpillar of the Black swallowtail butterfly. (Author taken June, 2017, mouth end is down).

4:00 p.m. It is natural for people when enjoying a late afternoon walk up the stream cooled canyon road to give more attention to mammals and birds than to the dominate plant community. Birds sing for beautiful songs us, and thus, we imbue them with more anthropomorphic sentience than they possess. Peregrine falcons and Red-tailed hawks soar and hunt like us with purposeful intent. Mule deer stare back with quizzical large-black eyes through which we feel we can see their souls. Coyotes watch us with the familiar intelligence of our domesticated dogs. Mountain lions in the canyon follow our motions, and we can see behind their cat eyes, a decision process to ignore us like our house cats or to begin hunting us as prey. People do not generally extend the respect given to these more conscious animals to the machine-like insects. We appreciate butterflies and bees and fear wasps and spiders, but otherwise our fascination with insects goes to the grotesque or brightly colored. Plants do not engage us like birds or coyotes, so in our perception they fall into the category of uninteresting background. But plants are the dominate form of life on land and in the canyon.

I need a boost before leaving on my daily jog, and today, I brew and drink a cup of coffee before leaving home like more than 100 million other Americans. Drinking coffee is recommended before exercise to enhance endurance (Hodgsen, Randell and Jeukendrup 2013). I am unconscious of the fact that the cup of coffee, a drink enjoyed by billions every day, is a brew of some 800 plant-created chemicals that are insecticides (Hartley 2009). Organic gardeners also recommend brews made from other common food plants that humans enjoy, like onions, garlic, and red peppers, because they also contain insecticides that kill certain insects on contact. Organic gardeners also recommend tea as a fungicide, but it is also consumed by another 100 million Americans each day without ill effect.

A caterpillar of the Black swallowtail butterfly (Papilo polysenes) lays on the road, severely dehydrated, and I help it to the cool of the roadside grass and then dose it with water. In its caterpillar phase, it is bright green with black strips and bright orange spots. Like other swallowtail caterpillars, it has a gland that emits a foul smelling odor that deters predatory birds. Thus, its clown-like outfit is to warn birds that no meal can be had. Conversely, the hungry caterpillar, like the others that have fallen on the road during the spring (April 13th, May 7th, and May 13th), landed here due to a defense of the surrounding trees, including the Gambel’s oak trees. Many canyon’s stream associated trees, including the oaks, the Rocky Mountain narrowleaf cottonwood trees, and the River birch trees, are covered in wax on their upper sides. This aids in conserving water under today’s hot sun, but it is also defends the trees against insects. Insects, like the swallowtail caterpillar, slide off even though they have evolved specialized feet to aid them in grasping the leaves (Hartley 2009). Other plants in the canyon have obvious defenses. The few Stinging nettles (Urtica dioica) that exist in the lower canyon, viewed microscopically, are covered in small, barbed, poison-tipped silica spears, and this accounts of the strong skin rash that develops when they are brushed against (Hartley 2009). In the canyon, both Cheat grass and Yellow star-thistle set bristled seeds that makes them unpalatable to mule deer.

But in the Darwinian competition for survival, land plants are winning over animals.

* * * *

Per Thoreau’s “Journal” on June 30th, 1840, he describes the wind by its effects on plants and his mood. On June 30th, 1851, he sees blue flag (Iris versicolor) and a small aster. He describes the smell of fresh shoots of fir-balsams. On June 30th, 1852, he cites as a marker of summer is when wild roses, morning glories, orchids, blue-flags, fireweed, mountain laurel and white lilies all bloom at once. On June 30th, 1860, he takes the temperatures of the air (83 degrees), spring water (45 degrees), river water (77 degrees), and the ground three inches beneath the surface. He notes that river meadows where light penetrates are at the height of their beauty.

* * * *

Most plants in City Creek Canyon taste bitter and are inedible. Typical advice given for foraging for wild foods is to taste a small bit of the plant and then wait to see if you become violently ill or if your tongue breaks out in a rash. In 2009 a speculative but provocative lecture series, British ecologist Sue Hartley describes how in the oceans, about half the plant biomass is consumed by animals (Hartley 2010; see Hartley 2009). On land, animals consume only about 20 percent of plant biomass, and this is because of the extensive chemical defenses that plants have co-evolved to deter animals from consuming them. Hartley explains that where animals can eat a particular plant specie, they usually have evolved a genetic resistance to that plant’s chemical defenses. For example, cabbage contains chemicals that make it partially toxic to domestic livestock and rabbits, but the human gut has evolved to tolerate its poison. Similarly, caffeine and tannin in tea and coffee plants are those plants’ biological insecticides and fungicides, and their poisons only incidentally and accidentally provide billions of drinkers with a desired pharmacological boost. In contrast in the canyon, Scrub jays, Rock squirrels and mule deer eat the acorns of Gambel’s oak trees. To humans, the oak’s acorns are bitter and inedible, but after leeching out its toxic gallotannins for several days and much labor, the acorns can be processed into a gruel or flour. Hartley notes land plants and animals co-evolve. Plants become toxic to prevent being eaten, animals gain resistance and eat more, plants increase the dose or develop and entirely new toxins to ward off animals. Hartley opines that since land animals can consume only small portion of the total terrestrial biomass, plants are winning to co-evolution race (Hartley 2010). In the canyon, plants do not sing, fly, or leap to our delight, but they and not us are in control.

* * * *

On June 30th, 2002, Great Salt Lake Audubon plans a bird watching hike up City Creek Canyon (Salt Lake Tribune). On June 30th, 1996, coliform levels in City Creek Canyon stream have quadrupled in the last few years, and the City is considering replacing outdated restrooms in the canyon (Salt Lake Tribune). On June 30th, 1919, Water Commissioner Clarence C. Nelsen opined that recent water shortages were caused by city residents wasting water (Salt Lake Telegram). Salt Lake City delivers 42,000,000 gallons of water, or 350 gallons per resident each day. Nelson notes that Los Angeles, a city five times the size of Salt Lake City, uses only 20,000,000 gallons of water each day (id). On June 30th, 1910, City Councilperson L. J. Wood gave his views on the proposed repeal of the prohibition of automobiles in City Creek Canyon (Salt Lake Tribune):

“Another phase of the affair is that the people who cannot afford to hire conveyances and go to more distant places can easily take their lunches and other accompaniments for a day’s outing, and go up City Creek canyon, where they can be free from molestation by buggies, motorcycles and automobiles. It is now the poor people’s pleasure spot and should be kept free from any privileges that will change the present enjoyable features of the canyon as nature arranged it” (id).

In response, on July 1, 1910, a Salt Lake Tribune editorial argued that the road should be improved by adding paved pedestrian walkways and then opened to motorists. (In 2014, United States President Barrack Obama designated the San Gabriel Mountains north of Los Angeles in the Ashley National Forest as the San Gabriel National Mountain. He did so in response to complaints by low-income minorities that they had inadequate park lands on the Los Angeles Valley floor for recreation.) On June 30th, 1904, the water rights claim of Douglas A. Swan in City Creek Canyon was denied by the City Waterworks Committee (Salt Lake Tribune). On June 30th, the City Board of Public works approved specifications to lay a new iron pipeline up City Creek Canyon (Salt Lake Tribune).


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