Eco-Gallery: Essay: The Human Imapct


	Globemallow and tiny phacelia crenulata on the cracked floodplain of the Tohono O’odham Indian Reservation. ©Jack Dykinga

Last night I stood in the Sonoran Desert’s first summer rain and could hear the earth sigh as the long groaning of the dry months passed. I’ve spent my life here waiting for rain. Sometimes, the rains whisper in and out and sometimes they stay away for years. We find the heart of the desert in that zone where the rains measure less than ten inches a year and the evaporation rate runs at least a hundred inches a year.

When the June rains came last night (the first substantial moisture since last September), my city of Tucson, a metroplex of 900,000, announced that mandatory water restrictions might not be necessary. The problem, you see, had passed and could now be forgotten. But of course, the problem never had existed because, for the desert, water shortages don’t exist: there are just the rhythms and hard truths of this biologically rich ground raked by dry winds and domed by skies empty of clouds for months at a time. I’ve got an ironwood tree in my yard that should be good for five hundred years, a boojum that can hit eighty feet given seven or eight hundred years. They belong here.


Wrinkled, dying, and sun-colored leaves of the agave plant. ©Jack Dykinga

Creatures who belong here conform to desert extremes. The saguaro, the giant columnar cactus, functions as symbol of this desert — of dryness -- and yet the saguaro survives by being a giant water tower largely immune to the fickle weather patterns with widely varying rainfall. The mesquite either lives as almost a shrub on the dry plains or thrives as a tree along the washes where its deep roots (found once at two hundred feet) drink greedily in spite of the cloudless skies. The annual flowers live in a fantasy of rains, quick growth and flowering to the casting down of seed and then incineration when the rains, as always, vanish once again.

Many creatures adapt by evading the extremes of heat (120 degrees to freezing) and dryness. Success is measured in natural abundance: the Sonoran Desert hosts around 130 species of mammals, 500 birds, 20 amphibians, around a hundred reptiles and say 3500 types of plants. Some animals migrate (such as the hummingbird); others are active only in morning and evening (crepuscular) or are nocturnal. Some practice estivation (a hot weather hibernation) and/or winter hibernation; some toads remain dormant until it rains.


	Monsoon clouds fill the sky near the antelope hills, Cabeza Prieta National Wildlife Refuge. ©Jack Dykinga

Once when I was a boy out hunting, I sprawled under a palo verde tree to rest and watched a Gila Monster saunter past like a God. At the moment, I thought such a creature summed up the desert know-how that I lacked. And in a sense, I was right. The venomous lizard with its orange and black markings spends ninety-eight percent of its time underground evading the Sonoran desert.

Human beings struggle for balance of power: an endless lover’s quarrel with this place. Some estimates figure sixty percent of the Sonoran desert has been displaced by alien species released by our kind. Some scholars argue that Clovis Man, an early hunting culture, wiped out the mega fauna of mammoths and other giant mammals eight to ten thousand years ago.

More recently, after World War II, pump irrigation drained deep desert aquifers and in a single lifetime destroyed them, thereby destroying the desert agriculture grown dependent on the wells.


A fallen and decaying Saguaro cactus against volcanic ash. ©Jack Dykinga

Today, large cities metastasize at the desert’s edge where mountains feed rivers and water tables in Tucson, Phoenix and Hermosillo. Large water dreams, such as the Central Arizona project (a $5 billion scheme that makes part of the already overtaxed Colorado River run uphill into central and southern Arizona) simply prolong the avoidance of reality. I now live in a house in a city with a sinking water table and a growing population. This is one more way to manage here: mine the resource and then when it dies, die with it.

But nothing has changed. The reality I first glimpsed as a boy when that Gila Monster ambled past, unconcerned and at home, persists. Here a successful life form either evades the desert through dormancy or storages like the Saguaro or keeps moving like the hunter/gatherers or the migratory birds. The final choice is to make a stand and die like the modern Sunbelt civilization.

That is the beauty of deserts. All the lies stop here. Or life itself stops.