Protecting Colorado’s Ecosystem
Anna Sher
Anna Sher has spent more than a decade trying to protect Colorado’s ecosystem.
Sher, an associate professor of biology, has been researching effective ways to prevent the spread of tamarisk, an invasive species of weed that can drive off native wildlife. She's traveled the West, studied the ecological impacts and potential solutions and lobbied for change and involvement.
"The problem with tamarisk is that it's able to establish itself and effect other changes to the ecosystem that are harmful to the original plants and animals," says Sher, who also directs research, herbaria and records at the Denver Botanic Gardens. "It changes the structure of the forest."
What is tamarisk?
Imported from Asia in the 1800s as an ornamental, tamarisk spread from gardens to natural waterways, boosted along the way by planting programs to control erosion. It spread across the West, and concentrations are now found on an estimated two million acres throughout the Western and Southwestern U.S.
The plant, also known as salt cedar, creates salty soil conditions around it -- conditions that are inhospitable to native plants. It can also increase fire intensity and frequency. And tamarisk gobbles up water, depriving farmers and cities downstream.
Working toward a sustainable future
President Bush signed a bill into law in 2006 authorizing the government to study and direct management of tamarisk, and a DU panel last year called for eradication of tamarisk and other invasives as part of a nine-point plan for a sustainable water future.
As scientists develop ways to eradicate tamarisk, there is new debate over whether they should, Sher says. If tamarisk goes, what replaces it? Will native species return to vacant plots now that the soil has been left high in salt? And what about birds that have adapted to tamarisk?
Science as a solution
Sher, who also serves as board president of the Colorado-based nonprofit Tamarisk Coalition, says scientists' challenge is to understand the role of tamarisk while pushing for research into tamarisk and the effects flood control and other water policies have on natural landscapes.
And the work is more important than ever as demand grows.
"In arid ecosystems, rivers are the veins of life," she says. "Whatever we do to them has an effect on the entire region."
Published on Nov. 10, 2008