Groups such as the Center for Biological Diversity criticized the plan, arguing that expanded livestock grazing harms threatened wildlife and causes ecosystem degradation.
But this professor said it’s not that simple.
Osvaldo Sala is an ecologist and professor at Arizona State University, and the director of the Global Drylands Center — he’s also co-author of a recent paper on what experts call de-stocking: the decline in livestock around the world.
The Show spoke with Sala about the nuances of the global grazing environment.
Full conversation
OSVALDO SALA: You can think about the whole world is either urban area, croplands, forest or drylands. Drylands are the largest. Almost 50% of the world, of the terrestrial surface, is covered with drylands.
And the narrative is that drylands are being degraded because of overgrazing. Overgrazing means that we humans put too much livestock, that eats too much grass. But in approximately half of the world in the last 25 years has been what we call de-stocked.
SAM DINGMAN: And that's reductions in livestock, correct?
SALA: Yeah, livestock, but it also depends on different parts of the world. So in North America, it's mostly livestock.
DINGMAN: OK.
SALA: But in Africa, it could be goats could be buffalos or other kind of animals.
DINGMAN: Can you put in context for us, why is that a problem, globally speaking? What is the significance of this de-stocking?
SALA: It is both a problem and an opportunity. But we have to take advantage of the opportunity and prevent the problem.
So, for example, increases in amount of grass that accumulates because of reductions in stocking rates increases the probability of fire. So that is a danger.
DINGMAN: Right.
SALA: And also, depending on the region, can reduce biodiversity. But grasslands, they are overgrazed, tend to lose species diversity because some of the plant species that are preferred by animals may be degraded or driven to extinction. But the same thing happens on the other end when the grasslands are abandoned, instead of having a diverse composition of plants and they end up with just one that dominates.
DINGMAN: And so just to drill down on the numbers a little bit, I believe you found that livestock populations have shrunk by about 12% over the past 25 years?
SALA: Geographers always say that by changing the scale, you change the answer to the same question.
DINGMAN: I see. OK.
SALA: So in very, very coarse, the major driver of these global changes is wealth. So the variable that explains the changes in stocking rates in the last 25 years is GDP. The wealthiest countries of the world tend to de-stock, and that is all North America, southern Europe, now China, Australia. Those are exhibiting decreases in stocking rates.
The poorer countries in Central Africa and South America and India, Pakistan, are increasing.
DINGMAN: At the risk of asking a foolish question, help me understand why wealthier countries tend to de-stock. That seems sort of counterintuitive to me.
SALA: There are several reasons. Some of them we know and some that we don't know. For example, we know that the meat demand is the same all over the world, in poor and wealthy nations. And there is a much larger increase in human population in the underdeveloped part of the world. And so if everybody is eating about the same amount of meat, the demand increases more in the developing world.
DINGMAN: I see, I see. So the demand is higher in places where the population is increasing at a faster pace, correct?
SALA: The other thing is that there is more resources in the ... wealthy part of the world, then therefore the efficiency with which we grow animals is much higher. So we need, with fewer animals, we produce more or less the same amount of meat.
DINGMAN: So what do you make, Professor Sala, of the administration's recent move to expand private livestock grazing onto national forests and other public lands, considering, as you were just explaining, that there doesn't seem to be rising demand here in the U.S.?
SALA: Most of the land, public land in the West, is managed by one or other federal agency. The Bureau of Land Management, the BLM, is the major land manager in the West. And they have pieces of land that they rent for ranchers to bring their animals to graze.
And so I published a paper, like 10 years ago, showing that there's a decline in the number of cattle, and they never meet the goal that the BLMs has set for their land. So there is more supply of land than there is demand.
DINGMAN: So if I'm following that correctly, that would make it somewhat curious that the administration is trying to proactively increase the amount of land of which there's already a surplus?
SALA: Yes, it seems to be counterintuitive. There is more supply than demand.
DINGMAN: Well, so let's come back then to what you were saying at the beginning of our conversation, which is that leaving all of that to the side for the moment, but according to your analysis, it could still be a potential opportunity to allow increased grazing.
So for somebody who's listening to this and has environmental concerns about the impact of increased grazing on public lands, talk a little bit more about why, if handled properly or managed correctly, that could be a beneficial thing.
SALA: So, grazing is not necessarily good or bad. There is an optimal level of grazing. So, if land is overgrazed, at any reduction, de-stocking rate will be beneficial.
But if land is not overgrazed, I mean, decreasing of stocking rates will increase the probability of fire, they will reduce the amount of water runoff, that is the amount of water that we can drink out of rivers and streams.
The answer to that question is it's regionally dependent. So most of the U.S., in my opinion, is not overgrazed. But I don't think that we are arguing that we need to increase rates. I think it's a decision that depends on the location. There may be still parts of the U.S. that are overgrazed, and there are parts that are undergrazed.
DINGMAN: So I suppose at the end of the day, it comes down to how granular the approach of the administration will be when it comes to this.
SALA: With humans, too. I mean, you cannot say that it'd be good if Americans eat less. Maybe for some, but not for others. It would be good to tailor the answer to the individual that you are thinking about.
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