Goat eating buckthorn

A goat dines on buckthorn.

Q: So the city of North Mankato wants to use goats to control buckthorn. From what I know, eating off the top of the plant results in more new growth the next year. And goats eat every other plant and beneficial young tree as well, yes? How will this not make the problem even worse?

A: Ask Us Guy doesn’t have a lot of goat knowledge but he will provide a well-researched, scholarly, peer-reviewed answer to this question — in two years.

That’s when a team of researchers at the University of Minnesota is set to finish its project: “Understanding the benefits and limitations of using goats for invasive plant control.”

Currently, there hasn’t been a solid academic study on the question, according to Tiffany Wolf, a principal investigator in the research project.

“Goat management has surged in popularity, but proof that it works in the long-term is lacking,” Wolf wrote in a summary of the $456,000 study. “This project will evaluate the lasting benefits of goat defoliation for buckthorn management and determine if feeding poses harm to the native plant ecosystem.”

Wolf notes that there are solid reasons that park managers and other landowners are hoping that goats might be a real solution to the spread of buckthorn and other nuisance species.

“Managing invasive plants is expensive and labor-intensive,” she wrote. “The high cost of conventional tactics like mowing and herbicide application has led managers to look to less traditional methods of control, including browsing goats.”

A less-extensive study was done a decade ago by the owner of a Wisconsin goat herd with $1,900 in government funding.

Kimberly Hunter, in a description of the study to the U.S. Fish and Wildlife Service, said goats’ dining preferences start with “woody plants, favoring buckthorn, multiflora rose and honeysuckle over young oak or hickory. Second choice is broad-leaved plants like thistle, burdock and curly dock. Last on the list is grass and hay crops like alfalfa and clover.”

Goats will also eat native flowers and native tree seedlings, Hunter wrote: “I handle this by targeting the graze to avoid the critical growing times for these plants or putting a temporary protective fence around the native plant.”

It’s true, as the reader suggests, that chewing off the above-ground portion of buckthorn doesn’t immediately kill the plant. But with repeated grazing by goats, the root-system is weakened and starved, and the plant will die. So the animals need to be invited back when regrowth occurs.

Goats, being short creatures, can’t do anything about tree-sized buckthorn, so those need to be cut down or sprayed with herbicide. Goats, however, will work together to eat smaller trees even if the plants are higher than a goat can reach. One goat will stand on its back legs, bend the young buckthorn down and hold it while others in the herd chow on the leaves.

So, goats alone won’t fix an area where large mature buckthorn have taken over, and it’s not a one-time fix. The upside, according to Hunter: “Goats work 24/7 without benefits.”

They’re also putting their lives on the line in some cases, according to the University of Minnesota. A deadly parasite that can kill goats is found in woodland snails. So, the U study will also look at whether goose grazing in advance of goat grazing might be an answer to keeping the goats safe (and reducing the costs of goat grazing that come with goat mortality). The idea would be that the geese can safely eat the snails, paving the way for the goats to do their job.

Finally, one potential issue the reader didn’t raise — whether goats might simply spread the buckthorn seeds through their feces — has already been addressed by the U’s College of Veterinary Medicine. Researchers fed goats buckthorn berries and recorded how many seeds passed through.

Turns out the goats’ digestive system is very effective at destroying the vast majority of the seeds. About 63% of buckthorn seeds not eaten by goats were capable of growth. Of the seeds eaten by goats, only 2% of the seeds passed through. Of that 2%, only one of every nine seeds was still viable.

Q: Question for the all-inquisitive Ask Us reporter.

Is there a legal set-back for political signs to be placed from the roadways? The majority of signs are placed in lawns but on County Road 33 there is a bright yellow political sign at the very edge of the road. Is this legal? It appears to be a distraction/hazard for people driving on the county road.

A: Under Blue Earth County ordinances, private signs of any sort cannot be in the public right-of-way. So a sign that’s literally “at the very edge” of a county road would probably violate that portion of the ordinance.

Political signs are allowed on private property without any sort of permit or government permission, so long as they are eight square feet or less in size and not located “on any intersection so as to obstruct vehicular lines of sight.”

Contact Ask Us at The Free Press, P.O Box 3287, Mankato, MN 56002. Call Mark Fischenich at 344-6321 or email your question to mfischenich@mankatofreepress.com; put Ask Us in the subject line.

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