Virtual fences are a pollinator-friendly option for ranchlands

The Annual Meeting will be held 9-13 December at the Walter E. Washington Convention Center in Washington, D.C., where more than 28,000 scientists will gather to discuss the latest Earth and space science research.

In the new study, researchers at Oklahoma State University investigate how virtual fencing technologies could ease ecological impacts on grassland vegetation. The phrase "virtual fence" might evoke images of those invisible dog fences in backyards, but there are some key differences. There is no buried fence line, and the boundaries can be changed easily with a computer. As cows wander toward the fence, they receive an auditory warning from their collar. If they ignore this and move closer to the fence, they receive an electrical stimulus similar to one from an electric fence.

Previous work on virtual cattle fences focused on their efficacy for containing livestock, such as excluding the animals from sensitive ecosystem areas that are being restored, said Timothy Olsen, a natural resources masters' student at Oklahoma State University and lead author of the study. Olsen and coauthor Bryan Murray wondered how virtual fences might affect the vegetation structure and heterogeneity of grassland in grazed areas.

Previous studies showed that continuous grassland habitat is more beneficial for supporting bird and pollinator diversity and abundance than fragmented habitat. The researchers hypothesized that the warning from the collar as cattle approached the virtual fence would prompt the animals to graze more randomly, rather than forage right up to a physical fence -- making the ecological boundary between grazed plains and natural grassland more gradual.

To test that, the researchers set up six 1,000-square-meter study sites at the Oklahoma State University Bluestem Research Range. Within the grassland pasture, the team created linear boundaries, with three plots with physical fences and three having virtual fence lines. The cattle grazed in the study sites during the spring and summer seasons.

Using drone imagery, the researchers surveyed the six sites and created height models of the vegetation. They then compared the vegetation heights in the traditional fence and virtual fence with ungrazed rangeland. They found the virtual fence created a gradual transition more than 15 meters (50 feet) from the fence, changing from native grassland to fully grazed grass. Additionally, in the virtual fence areas, the researchers found a greater variation of vegetation heights compared to the fenced rangeland. This transitional zone could help increase native habitat for pollinators and birds.

Olsen notes that while virtual fences can help create stronger ecosystems, they can also help ranchers. Fences require time, money and labor to install and maintain, and they are static features ranchers have to work around.

"Virtual fences are an easy way to manage livestock, saving time and labor," Olsen said. Instead of hiring a team to herd and move cattle from one area to another, the grazing area can be changed remotely on a computer.

Ranchers could also use virtual fences to intentionally create more gradual shifts to grazing areas. "Some studies have looked at virtual fences for rotational grazing where over a period of time, managers can gradually shift the grazing area, nudging cattle to a new field," Olsen said -- no fences or herding required.