The Dixon Water Foundation’s Mimms Unit in Marfa will be profiled on RFD TV’s Out on the Land on February 4 and 5, 2014. For showtimes and channel information please visit Out on the Land‘s schedule. [The complete episode is now available online.]
MARFA – Laughter and moos filled the air as a herd of children met the herd of cattle at the Dixon Water Foundation’s Mimms Unit last Friday, during the Marfa International School’s week-long “Living Classroom” at the ranch.
Twenty-four students from kindergarten through eighth grade learned about desert grasslands and sustainable land management through science projects and presentations by local experts. The children experienced what it’s like to be a wildlife biologist tracking animals; to be a scientist monitoring water and soil quality; and to be a botanist identifying grasses and collecting native plants. Chasing grasshoppers, listening to birds, and writing about the landscape were also part of the program.
“This has been amazing,” said teacher Lisa Gordon. “To be outside actually doing this kind of science has so much meaning.”
The Dixon Water Foundation’s President and CEO Robert Potts introduced the ranch’s cattle management system, which mimics the grazing habits of native bison to conserve water, wildlife and the desert grassland.
“Cattle are the tool we use to keep more rainwater in the ground, improving the soil and improving the grassland,” he told the students, before demonstrating how he moves the ranch’s herd between pastures.
Mark Brandin, Marfa International School director, said the week was an enriching and memorable experience for all of his students.
“I believe each child at MIS now has a much greater appreciation for the unique land in which we live, and we look forward to further studies at the ranch throughout the year,” he said.
The Dixon Water Foundation frequently welcomes students to its ranches in Marfa and northeast Texas. Last month Marfa ISD eighth-grade students had a nature writing workshop at Mimms, and Sul Ross State University wildlife management students took a field trip there in September.
Educators are invited to contact Potts at firstname.lastname@example.org for information about visiting the ranch, as well as to discuss funding opportunities for using the ranch as a classroom.
MARFA – Rodent researcher Bobby Allcorn had a busy September. Each week the Sul Ross State University graduate student trapped hundreds of small rodents—from petite silky pocket mice to husky wood rats—on the Dixon Ranches Mimms Unit. That’s great news for a host of other wild animals.
“The effects of the Rock House Fire, combined with the drought, devastated the small rodent population,” said Allcorn, whose research is funded by the Dixon Water Foundation, a non-profit that promotes healthy watersheds through sustainable land management. “These animals do rebound with precipitation though. And they’re coming back in force.”
In 2011, the Dixon Water Foundation partnered with Dr. Bonnie Warnock of Sul Ross’s Borderlands Research Institute to monitor the small-rodent population on the Mimms Unit. Then the historic Rock House Fire burned most of the ranch on Marfa’s northwest edge.
Without vegetation to eat or hide in, the number of mice and rats crashed, to the point that researchers rarely caught a rodent. The effects ricocheted throughout the food web, from bobcats to quail.
“Predators eat small rodents, so if there aren’t any small rodents, larger animals become prey more often,” Allcorn said. “For example, pronghorn really suffered after the fire. Not only was there no forage for them, but predators went after them more.”
Small rodents play other roles in maintaining healthy grasslands. They disperse seeds and can even alter the plant composition of an area.
“They’re a representation of overall ecological health,” Allcorn said.
Allcorn will finish his small-rodent research next year, at which point he’ll be able to draw more conclusions.
“But for now I can say the population and diversity have certainly increased since last year, due to the rainfall,” Allcorn said. “That’s a great thing for all the other animals and the environment.”
How did the Rock House Fire and 2011 drought affect soil microbes at Mimms Unit? That was the subject of a recent research project by Masahiro Ohnishi, a Natural Resource Management graduate student at Sul Ross State University in Alpine. The Dixon Water Foundation funded Ohnishi’s research, which was featured in “The Road to Recovery” in the July 2013 issue of Texas Wildlife, republished here with permission of the Texas Wildlife Association. Ohnishi’s research was featured previously in the May 16, 2013 issue of the Big Bend Sentinel.
MARFA – Two years ago, the Rock House Fire and a record drought scorched most of the Dixon Water Foundation’s Mimms Ranch outside Marfa. The effects aboveground are still obvious, where grasslands are punctuated by patches of barren earth. But how did the fire and drought affect microbes toiling in the soil to create the nutrients grasslands require? This subterranean recovery was studied recently by Masahiro Ohnishi, a Natural Resource Management graduate student at Sul Ross State University in Alpine.
“We wanted to see what kinds of bacteria and archaea are in the soil after the fire and after the drought, and how they recovered from these huge disturbances,” says Ohnishi, whose research was funded by the Dixon Water Foundation, a non-profit that promotes healthy watersheds through sustainable land management.
Bacteria and archaea are single-celled microscopic organisms that are found practically everywhere—from deep-sea vents and arctic glaciers, to cattle intestines and human belly buttons. Many microbes belong to nature’s recycling crew; they break down dead plants and convert them into nutrients required by living plants. Microbes also help create a complex soil texture, which in turn allows seeds to take hold and more rainwater to soak into the ground. All of these functions make soil microbes essential members of a desert grassland ecosystem.
To determine which microbes populate Mimms Ranch, Ohnishi analyzed the microbial DNA in soil samples collected from several unburned, burned and intensely overgrazed sites. Then he used statistical analyses to compare these microbial communities before and after the summer rainy season in 2012. He also looked for correlations with the amount of plant cover, soil nutrients, and other soil characteristics at each study site.
In burned areas, Ohnishi found nearly half as much microbial DNA as in unburned areas, indicating soil microbes had been hit hard by the fire and drought. But microbial activity recovered after the summer rainy season at both burned and unburned sites. Ohnishi observed a corresponding increase in the amount of certain soil nutrients needed by grasses and other plants, which also bounced back after the summer rains.
Ohnishi was particularly amazed by the diversity of soil microbes he encountered. For example, one five-gram soil sample—the weight of a nickel—was home to around 400 types of bacteria.
“There’s so much diversity, and these microbes perform so many functions,” he said. “We have no clue what they all do yet.”
Understanding what each soil microbe does will be up to future researchers. For now, Ohnishi’s research demonstrates that these microbes are part of the recovery process after a devastating fire and drought. And he envisions his research contributing to a micro-ecosystem approach to land management, in which supporting microbial activity would be a way to improve rangeland health.
Bonnie Warnock, associate professor of range science at Sul Ross State University, directed Ohnishi’s research.
“Both the physical and biological health of the soil is critical to healthy ecosystems,” she said. “We tend to take the soil for granted and forget that it is, in a very real way, the base for all life.”