Grazing cattle and sustaining bobwhite quail can be part of the same equation, says Kelly Reyna, our partner with UNT Quail. Reyna and our Bear Creek Unit were recently featured in this article, “Saving a Texas rite of passage, one ranch at a time,” on the North Texas Quail Corridor, an initiative to conserve this treasured but increasingly scarce game bird.
Desert rodents rebound after summer rains
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.”
While the drought persists, recent rains have been a boon to small rodents, like this silky pocket mouse found on the Dixon Ranches Mimms Unit near Marfa. (By Bobby Allcorn/Borderlands Research Institute)
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.”
Dixon-funded research on soil microbes featured in Texas Wildlife magazine and Big Bend Sentinel
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.
Soil still teems with life after fire, SRSU student finds
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.
Ohnishi collects soil data at Mimms Unit (Photo by Nora Ohnishi)
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.”
Dixon funds Sul Ross researchers developing cattle for desert
This article in the Big Bend Sentinel describes Sul Ross researchers breeding cattle suited for grazing desert grasslands. Their research was funded by a grant from the Dixon Water Foundation.