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NMSU statistics professor helps study amphibian populations at Yellowstone

Responsible management of wildlife habitats and resources starts with a good understanding of the dynamics of the ecological system over time: Are populations and breeding sites changing? And if so, what are the reasons for that change? A New Mexico State University researcher is working with the National Park Service to help provide answers to those questions and give wildlife managers a clearer picture of how climate and habitat features affect populations.


Tiger salamander
A tiger salamander is one of the amphibians being tracked as part of an occupancy modeling study in Yellowstone and Grand Teton national parks. William Gould, associate dean for research in the New Mexico State University College of Business and a professor of applied statistics, is in his 10th year working with the National Park Service to model the distribution of breeding amphibians in order to better understand the dynamics of the ecological system over time. (Photo courtesy National Park Service)
William Gould fishing
William Gould, associate dean for research in the New Mexico State University College of Business and a professor of applied statistics, will spend a month in Bozeman, Montana, conducting occupancy modeling of amphibian populations in Yellowstone and Grand Teton national parks. (Courtesy photo)

William Gould, associate dean for research in the NMSU College of Business and a professor of applied statistics in the Department of Economics, Applied Statistics and International Business, is in his 10th year working with field researchers at Yellowstone and Grand Teton national parks to use occupancy modeling to look at the distribution of breeding amphibians across the landscape.

?Amphibians were adopted by the National Park Service as a vital sign for monitoring, and there are a lot of reasons for that,? Gould explained. ?One is that there have been significant amphibian declines over the last few decades worldwide, so there?s a lot of concern about them.

?The second thing that makes them very informative as a bioindicator of the environment is that they live in both a terrestrial and an aquatic environment,? he continued, ?and they?re sensitive to things like pollution, fungus and other things that can affect those populations.?

Researchers have collected data for the past 10 years on breeding populations of tiger salamanders, chorus frogs and spotted frogs in more than 500 locations in the parks. Gould will again spend a month this summer in Bozeman, Montana, using that data to estimate trends in breeding occupancy and a better understanding of the dynamics of the system over time.

?We?re trying to connect to those dynamics to a half-dozen different covariates, like elevation and wetland depth, and different climate drivers such as runoff and evapotranspiration,? he said.

This information helps researchers understand which features or aspects of an area might make it more or less likely to be occupied by breeding animals. That, in turn, can help a manager understand whether or not there?s a potential threat to their populations, he said.

?The National Park Service has a responsibility to manage these areas, not just for humans who come visit, but also for wildlife that exists within those areas,? Gould said.

Gould gained expertise in occupancy modeling through a faculty development opportunity funded by the College of Business. Since then, he?s collaborated on dozens of research projects and taught occupancy modeling to graduate and undergraduate students at NMSU and abroad, including as part of a Faculty-Led International Program, or FLiP, course in Costa Rica, which he teamed up with NMSU biology professor Timothy Wright to teach.

?The application of statistics to other fields is becoming increasingly important,? Gould said. ?Almost any discipline that collects information and wants to synthesize that information, they rely on statistical methods to do that, so having a background in statistics allows me to work with people in a variety of different disciplines.?

College of Business Dean James Hoffman said development training is crucial for faculty, allowing them to build on their expertise and return with valuable new teaching ideas and professional connections.

?Our faculty members are eager to use their time outside of the classroom to stay on the leading edge of their fields,? Hoffman said. ?Giving these individuals the opportunity to expand their academic knowledge and body of research makes them even better mentors and leaders for our students.?

The amphibian occupancy modeling project is a collaboration with the National Park Service, the U.S. Geological Survey and the Northern Rockies Conservation Cooperative. An article based on the first seven years of occupancy modeling data will be published in an upcoming issue of Ecosphere, a peer-reviewed journal published by the Ecological Society of America, available online at http://esajournals.onlinelibrary.wiley.com.