A Hike To Cienega Creek Provides A Glimpse Of Hope For Native Desert Plants.
By Kevin Franklin
LOOK OVER HERE--it's some cryptogamic soil," says David Hogan, a biologist/lawyer for the Southwest Center for Biological Diversity.
The towering Hogan lowers his six-and-a-half-foot frame to just a few inches off the ground and parts some dried grass. The rest of the people on this Southwest Center-sponsored hike to Cienega Creek gather around and peer at what looks like dark mold growing on dirt. Hogan explains cryptogamic soil is really a collection of microscopic, non-vascular plants that live on the surface of soil in dry climates. In undisturbed areas of Arizona, it can be found in large patches. The community of blue-green algae and lichens fix nitrogen in the soil, making it more usable by other, more complex plants. They also hold in moisture and reduce flooding.
"Cryptogamic soils," says Hogan, "are one of the best indicators of grassland health."
Hogan explains the fragile cryptogams are destroyed when heavy-footed animals like cattle repeatedly trod upon them. Now that cattle have been removed from this area, plant life like this has started to return.
As we amble along the creek-bed, Hogan points out many of the plants and animals along the way. We come to a collection of tamarisk trees. Tamarisk was introduced to the Southwest from Eurasia as a flood-control measure and has since taken over many riparian areas, out-competing native species like willows and cottonwoods, writes Janice Bowers in Shrubs and Trees of the Southwest Deserts.
While some birds and animals use the tree for cover, it doesn't provide the first-rate food and shelter of native plants, which many animals need to survive. For that reason, most land management agencies consider tamarisk a pest.
Hogan explains, however, the most likely plant to replace the hardy tamarisk in the disturbed soil is...tamarisk.
The fast-growing tamarisk thrives in damaged soil and in places with high salinity in the water, like the lower Colorado River where it has completely taken over.
"If the conditions here in the riparian area were rested from cattle grazing and the conditions in the uplands were rested," says Hogan, "the habitat would change so that tamarisk just wouldn't be able to compete.
"But to do that, land managers would have to acknowledge they're doing something wrong with the way they administer the land under their care. It entails having to change the status quo, and the Forest Service and BLM are not going to do that voluntarily."
In protected Cienega Creek, the tamarisk are clearly being out- competed by the natives. Hogan points out a grove of 15-foot cottonwoods he says are only three years old. Given the right conditions our native species thrive.
Groups like the Southwest Center for Biological Diversity are taking an active hand in ensuring Cienega Creek remains one of those places with the right conditions. A few months ago they had a group of people planting native sacaton grass in a dried-out, mud-cracked field populated mainly by Russian thistles, a.k.a. tumbleweeds. Like the tamarisk, tumbleweeds are an unproductive, non-native invader.
"They're doing well," Hogan says on inspection. He hopes the sacaton, which can grow five feet high, will spread out and eclipse the tumbleweeds. After that, the carpet of grass will begin to revitalize the soil, and eventually the area might return to the towering mesquite forest it once was.
Like the fragile ecosystems in the Amazon destroyed by short-term thinking, when the forest here was cleared, the top soil soon left with it. Agriculture became futile and the area was abandoned as a wasteland.
Now, a six-inch clump of grass planted by hand is a symbol of new hope. The story parallels that of ailing riparian areas throughout the desert Southwest. Perhaps if more people get involved, efforts to restore our vital habitats will grow in kind.
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