Tech Researchers and Bosque Revegetation Project

SOCORRO -- New Mexico Tech geoscientists currently are conducting a study of soil and groundwater salinities at the Bosque del Apache National Wildlife Refuge, hoping to provide essential information to habitat managers who are starting to revegetate some of the 4,000 acres of the refuge which were burned during last spring's bosque wildfires.

Bruce Harrison, assistant professor of environmental geology at New Mexico Tech, Jan Hendrickx, associate professor of hydrology at Tech, and their research colleagues are using electro-magnetic-field measuring devices to survey and map soils in cleared-out areas in the Bosque del Apache, identifying "hotspots" of high salinity that are not conducive to growing native species of trees, such as cottonwoods and willows.

Salinity is a measure of the concentrations of salts and other mineral substances commonly found in most waters and soils.

An initial and important component of the ongoing revegetation project being mounted at the Bosque del Apache is a plan to eradicate, or at least control, the proliferation of the thick, choking stands of salt cedar trees, or "tamarisk," an introduced, exotic species which has taken over vast stretches of the Middle Rio Grande valley's bosque ecosystem.

"Some people think that salt cedar actually tends to accumulate salts, changing the salinity of the ground around it," Harrison says, "but no one has definitely proven this is so.

"And, still others believe that salt cedars use up more water than most plants, which is another 'maybe,'" he adds.

In an attempt to shed more light on these lingering uncertainties about managing the bosque, Harrison, Hendrickx, and Tech graduate students Deborah Stevens and Jelle Beekma, have also set up a network of 40 testing wells in an acre of refuge land infested with salt cedar to measure short-term changes in groundwater levels and salinities.

"As researchers, we have found that an added benefit in working at the Bosque del Apache is the structured management program that has been in place since the refuge's inception," Harrison points out. "For instance, if certain areas have been flooded for the birds, we can then conduct electro-magnetic surveys there to see if flooding may be causing those areas to become more or less saline. . . . Part of our research focuses on looking at the effects of management on salinity."

Harrison adds that the research project also will involve collecting data on groundwater depths, stratigraphy above the groundwater, and surface features of various areas on the Bosque del Apace National Wildlife Refuge.

"Much of what we learn here at the Bosque del Apache is applicable to other large bosque areas of the Rio Grande drainage," Harrison says. "This research project will have benefits to anyone dealing with bosque management issues, from the pueblos that are starting their own revegetation projects to the farmers who depend on irrigation. . . . Through this research, we're hoping to provide valuable information about the relationships between groundwater and soil salinities and reclamation and management practices along the Rio Grande."

Financial support for the research project has been made available through the Bosque Improvement Group, which receives federal funding through the efforts of U.S. Senator Pete Domenici. An additional $5,000 grant from the Office of the President at New Mexico Tech was earmarked for the project's efforts in helping to restore the recently burned areas.

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(George Zamora)