Previous research has suggested cattle are the next invasive species, being introduced to regions where cows were not previously found. While this has yet to be confirmed, their presence is currently an issue in Mongolia, where these grass-eaters are now overgrazing and destroying vital rangelands, a new study says.
As the name implies, rangelands are swaths of land including short and tall grass prairies, woodlands, wetlands and deserts that are grazed by domestic livestock or wild animals. And even though by definition these areas belong to cattle and the like, at least in Mongolia, there comes a point at which they can overstay their welcome.
According to rangeland ecologist Dr. Brandon Bestelmeyer, who led the research, a staggering amount of grasslands worldwide are impacted each year by too many livestock. This includes places from the western United States and Mexico to Kenya, Australia and even Iceland. In the United States, for example, 41 percent of all land is currently grazed by livestock.
As the economy in Asia continues to grow and pressures are put on the crucial agriculture industry, Mongolians in particular are struggling to save their rangelands.
"There's the possibility of continued decline in rangeland conditions - the term that's often used, and overused, is desertification. So if you have too many livestock and livestock numbers actually increase, and you couple that with periodic droughts, then you may run into some big trouble," Bestelmeyer, with the USDA Agricultural Research Service (ARS), Jornada Experimental Range, told Nature World News.
One challenge is that in Mongolia it's often unclear what healthy versus unhealthy rangeland is. It would seem obvious that degrading rangelands are characterized by barren ground and vegetation, however, the question is in determining what role overgrazing livestock play in this.
"If we've learned anything from 100 years of research, it's that location matters. You can't understand a particular landscape and ecology and its health until you get particular measurements in that area," added researcher Kris Havstad, supervisory scientist at the ARS.
So Bestelmeyer and his colleagues have relied on a concept called geological sites, which involves taking a piece of land in Mongolia and determining what it should look like without overgrazing. Havstad compares their technique to going to the doctor's. There's no one number that determines whether you're in good or bad health, but rather it's dependent on a whole set of numbers from various tests and how you interpret them. The same goes for assessing rangeland health.
Bestelmeyer is quick to point out that grazing in itself is not a bad thing, but it's a slippery slope between what constitutes grazing and overgrazing. Naturally the solution would be to merely take away the problem and reduce the number of livestock on these lands, but that's easier said than done.
"The precondition to rangeland management is to not have too many livestock so that you don't really have any options about where to put them. One of the first steps is how you get (at a landscape scale) the livestock to a level where you can manage the rangeland effectively," he explained.
Some of the types of interventions discussed with the Mongolian government include the taxation of animals, or a grazing fee, and making it a rule that land be in good condition if the people want to continue to use public rangelands. The hope is that eventually laws will be established that will restrict overgrazing, rather than simply requiring a fee; however, Bestelmeyer notes that that idea is a long way off.
Another issue is the conversion of rangeland to cropland to abandoned land. This is a concern that's seen in Brazil's Amazon as well, where forests are cleared for agricultural purposes, only to have grazing cattle quite literally abandon these plots and move on to greener pastures.
And if rangelands go, what are the cattle going to graze on? It's a self-perpetuating cycle in which dying rangelands leave less grass for the cattle to graze on, and yet those same cattle that overgraze create these barren rangelands in the first place.
Not to mention disappearing rangeland can have rippling effects on Mongolia's economy, which is highly dependent on agriculture. According to Havstad, about 25 percent of the region's gross national product, or GNP, comes from agriculture. Loss of rangelands can cause certain plant species to die and increased amounts of both wind and water erosion, sometimes to the point that the land is beyond saving.
In addition, rangeland loss has implications when it comes to food security. The global human population is expected to increase to a whopping 11 billion people. And as the world gets bigger and our food consumption needs rise, fertile agricultural land worldwide will be more and more vital to our survival. The researchers plan to continue helping Mongolians monitor their rangelands so that they can lead to a prosperous future... for cows and humans alike.
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