John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
Goats are better than herbicides when it comes to clearing weeds, say scientists.
There's no better way for a city to garner amusing headlines than by whipping out a bunch of goats for lawn-clearing duty. It happened this year in Seattle when the local transportation department used ruminants to eat unwanted brush ("Getting Their Goat"), last August when D.C. did the same in Congressional Cemetery ("The Kids Are Alright"), and that same month when the barnyard animals munched their way through O'Hare ("Goats Help 'Baaaa-ttle' Brush at Chicago Airport").
But there's another reason that cities keep flooding their land with goats. These bounding, human-voiced animals are extremely good at what they do—which is eating everything in sight. Their ironclad tongues and guts make quick work of tough or hazardous vegetation that humans struggle to control, such as blackberry tangles and poison ivy. Sure, they sometimes slack off to stand on top of each other, but under the supervision of a good herder they're a miracle for brush-clearing.
Now, there's even more evidence of their landscaping efficacy thanks to researchers at Duke and six other universities, including one in the Netherlands. (The world's most methodical minds are clamoring to be near goats, it seems.) Their focus, explained in the journal PeerJ, is how the creatures can be leveraged against a troublesome invasive grass from Europe, Phragmites australis.
The common reed thrives in salt marshes up and down the East Coast; it spreads rapidly, walls off scenic waterside views with 10-foot stalks, and can destroy native plants and change entire ecosystems. Americans have responded to the foreign grass with all-out war: There's been "digging, mowing, burning, flooding, grazing, and treatment with a number of different herbicides," according to the Michigan State University Extension. And it keeps coming back.
So the researchers obtained some goats and put them in test pens. According to their calculations, a pair of goats was able to chew a reed infestation from 94 percent down to 21 percent over the course of the study. Released in the wild, such hungry goats could make a big impact, they say, reducing the coverage of weeds by half in as little as three weeks. And in a nice side benefit, treatment by goats instead of herbicides allows native grasses to grow back (as much as five-fold, according to the study).
Duke's Brian Silliman, who led this research, believes that goats could be a cheap and sustainable supplement to more traditional reed-killing methods. (Indeed, New York City has already tried it.) He explains:
"This could be a win-win-win-win situation," Silliman said. Marshes win because native diversity and function is largely restored. Farmers benefit because they receive payment for providing the livestock and they gain access to free pasture land. Managers win because control costs are reduced. Communities and property owners win because valuable and pleasing water views are brought back....
The only drawback, he added, is that "people have to be okay with having goats in their marsh for a few weeks or few months in some years. It seems like a fair trade-off to me."