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NMSU-Jornada researcher to investigate regional monsoon phenomena

As the 2011 North American monsoon season winds down in New Mexico, the NOAA National Climatic Data Center reports that, as of early September, 72 percent of the state was still experiencing extreme to exceptional drought conditions. Given that the monsoon season is typically when much of the state expects more than half of its annual precipitation, optimism about the end of the drought is in small supply. And while there are no wildfires currently burning in the state, New Mexico experienced its worst fire year on record.

Debra Peters, an ecologist with the USDA Agricultural Research Service and an affiliated faculty member in two NMSU departments, has been awarded $400,000 from the National Science Foundation for her part in a large five-year study of how changes in monsoonal patterns are likely to affect vegetation and wildfire frequency in the Southwest. Peters is an expert on the grasslands and shrublands of the Chihuahuan Desert. (NMSU photo by Darren Phillips)

Debra Peters, a landscape ecologist with the USDA Agricultural Research Service at the Jornada Experimental Range near Las Cruces and an affiliated faculty member in the New Mexico State University departments of Plant and Environmental Sciences and Biology, has been awarded $400,000 from the National Science Foundation for her part in a large five-year study of how changes in monsoonal patterns in amount and timing of precipitation are likely to affect vegetation and fire frequency in the Southwest.

The study will attempt to project how climate change is likely to affect the monsoon phenomenon. One aspect of that project will be related to assessing the effects of future monsoonal patterns on invasive species and wildfire danger.

The $2.95 million collaborative research project, "Processes and Patterns in the North American Monsoon Macrosystem," is headed by Russell Munson, a professor of ecology at the University of Arizona, and involves more than a dozen researchers from UA, the University of Utah, the U.S. Geological Survey, the National Center for Atmospheric Research and two Sonoran universities, in addition to Peters from NMSU. In addition to ecologists, the multidisciplinary team includes hydrologists, climate modelers, land-surface modelers and dendrochronologists.

Peters' research focus in the project will be vegetation modeling. She will take the predictions of colleagues involved in the climate modeling, including projected temperatures and moisture, and incorporate that data, along with specific geographic and biological information, into ECOTONE, a computer modeling tool that predicts where and how robustly grass and shrub
species will grow.

The ECOTONE model has been used successfully to predict transitions between native grasslands and shrublands in the Chihuahuan Desert. Peters has been involved in that research through her participation in the Jornada Basin Long Term Ecological Research Program, funded by an NSF grant to NMSU.

"This new project on the effects of monsoons in the Southwest is part of a large regional effort that will provide scenarios of vegetation change resulting from climate change," Peters said. "The most effective way to make those predictions is through simulation models developed from long-term data collected in this region, in some cases for over 100 years. Long-term data provide the historical context for understanding and predicting the future."

A major focus relevant to New Mexico will be predicting the likelihood that invasive grasses will encroach into the Chihuahuan Desert. Cheat grass, buffalo grass and Lehman's grass, which originated in South Africa and which have established themselves in the lower Sonoran Desert of Arizona and northern Mexico, are likely suspects. These grasses are of little value as forage for livestock but produce bulk that would raise the danger of destructive wildfires in areas like the Jornada Basin.

Much of Peters' recent research has focused on the interaction of grasses and shrubs. The balance between those two types of vegetation can have a substantial effect on air and water quality, forage production, and biodiversity as well as the likelihood and severity of major wildfires.

Although residents may not think that New Mexico rangelands were spared in terms of wildfire prevalence and severity this year, Peters suggests that the current mix of grasses and shrubs in the Chihuahuan Desert is a much less volatile ground cover than the invasive grasses in the Sonoran Desert.

One possible scenario Peters and her colleagues will be evaluating is that climate changes in the Chihuahuan Desert will entail more spring moisture, which she thinks would be key to the future success of the South African grasses in New Mexico. Ironically, increased spring moisture could thus result in more fuel for wildfires than currently exists in the Chihuahuan Desert grasslands. And if those circumstances are coupled with less moisture during the monsoon season, her model would predict more serious wildfires in those areas.

In addition to the formal research results the project will produce, funds will also support educational projects, including training for graduate students, post-doctoral fellows and K-12 teachers, and the creation of a public display that will describe the research to the public.

For more information about the work being conducted at the Jornada Experimental Range, visit the website at http://jornada.nmsu.edu/