Noisy Deserts
Increased visitation and recreation in the desert inevitably leads to more human-generated noise. We talk with Joel Berger, University Chair in Wildlife Conservation at Colorado State University, about how this noise may or may not be affecting the iconic desert bighorn sheep. More specifically, we discuss how the noise may lead to increased prenatal stress on the females. The female bighorn typically give birth in the late Spring, which is when recreation in the SW desert is at its peak.
Meet the Scientist: Joel Berger
JOEL BERGER grew up in Los Angeles but traded surfing for desert and mountain adventures where, yes, he rode dirt bike. But gradually was attracted to wildlife and to science, and concentrated on animals larger than a bread box, where his first studies were on bighorn sheep, both in North America’s deserts and in British Columbia. There were also iconic endangered species and those lesser known. Among these have been African black rhinos and Tibet’s wild yaks, Patagonia’s huemul, and saiga deep in Mongolia’s Gobi Desert. In Alaska and the Russian Arctic, it was muskoxen for about a decade. As of late, I’ve had joint projects in our own backyard – bison, pronghorn, and mountain goats. During the past few years, I’ve focused on desert bighorns in SE Utah with a concentration on prenatal stress during late gestation. Past support has been from the Guggenheim Foundation, Smithsonian, National Geographic, and the National Science Foundation, as well as some federal and state agencies. His latest book is ‘Extreme Conservation – Life at the Edges of the World’. Joel is the University Chair in Wildlife Conservation at Colorado State University.
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Interview Excerpt - Human Noise and the Desert Bighorn
ScienceMoab: You you’ve been studying the desert bighorn sheep for a while now. I’m just curious why what kind of triggered you to start asking the questions of how noise is affecting the livelihood of the desert bighorn.
Berger: I was interacting with a number of folks in and around Moab especially in the noise ordinances and the increasing levels of aerial activity, whether it be tourist helicopters, whether it be sightseeing planes, there was starting to become an issue and it had been on and off over a couple of decades. people said Joel, since you’re focusing on Big Horns already in recreation, is there a way that you could get at the possible sensitivity of big horns to sound? So it came about through concerns by the local people: ranchers, recreationists, the business community, and government agencies.
ScienceMoab: It was brought to your attention that not a lot is known about the noise affecting the sheep, especially recreational noise in southeast Utah, so how did you go about designing this study?
Berger: So the major thing that we want to know is how big horn females are responding. Most of the recreation in southeast Utah occurs during the spring and late spring. This is exactly when females are in their last trimester of pregnancy. We know that it can be really stressful in late pregnancy, and that’s when animals need access to highly proteinaceous grasses. so we’re trying to understand what noise does to pregnant females. Wild bighorns in Utah are not in experimental settings, we don’t bring them into a captive facility to play sounds. So we need to be creative. we’re exposing females in groups to three kinds of sounds: the sounds of motorcycles, sounds of people talking, then we use a familiar sound, like a raven.
ScienceMoab: I know you’ve only had one real season collecting data. But what if anything, can you tell us what kind of insights into any of the trends that that you’re seeing what the data you found?
Berger: It depends on group size, and it depends on the habitat. What we’ve been finding so far, is that if the sheep are surprised, they respond pretty strongly. In other words, if they’re around a bend, and we know many of the trails, whether they’re hiking trails, whether they’re mountain biking trails, whether they’re motorcycle or other, or V kinds of trails, some runs straight, but some have a lot of turns and switchbacks in them. If the Sheep can’t hear things coming, they get surprised real quickly. And they’re likely not only to bolt, but to go far. So that’s that’s an important one, we know that they’re more vulnerable when they get surprised. Sometimes they hear the sounds coming, and they have a chance to prepare, and then they tend not to bolt, they just move off. And so on the one hand, if people are saying, yeah, the sounds aren’t that important. That’s an opinion. But some of our data may bear that out. But other times, and especially when the sheep haven’t been exposed, they bolt out of there, and we’ve had pregnant sheep move up to three or four miles at one time. That’s rare. That’s not the common but that’s kind of the extreme is what we’ve had on some responses.
ScienceMoab: So if your findings are that recreational sounds are adding more stress to the bighorns, especially the females, what do you hope could be some of the plausible outcomes of this study?
Berger: My hope would be that we would bring together different stakeholders, hold workshops across different parts of Utah, and get a much better feel for what the public is thinking and try to come to some sort of an agreement on where the best places are to put effort. How do we educate the public and make this work best for everybody?
ScienceMoab: So why are bighorn sheep so popular?
Berger: Your listening audience is in the realm of some of the best areas in the world for petroglyphs, petroglyphs, rock inscriptions, carvings, those have a bio cultural component that goes back 1000s of years, and other parts of the world petroglyphs go back 10,000 years. In the southwestern deserts we have more than 90,000 petroglyphs of which bighorn sheep for the animal ones are more than 50%. Obviously, if we respect the people who have come before us, petroglyphs are one way to understand what was important to them. If we want to honor not only tradition, but symbols that are still important, we need to think about bighorns.
