Researchers are seeing red flags in the health of Colorado’s elk herds, and new research aims to understand the role that recreation plays in declining wildlife numbers. Reporter Elizabeth Stewart-Severy broke down the details of that research with Aspen Public Radio’s Zoe Rom.
A local nonprofit, the Watershed Biodiversity Initiative (WBI), is working on a two-year study meant to identify the best habitat for wildlife. Once those places have been identified, where will this research go?
This study will help build a foundation that local land managers can draw from as they make decisions about how to use public lands. WBI, which is coordinating and raising funds for the study, has a science team that includes four agencies: the U.S. Forest Service, Bureau of Land Management, Colorado Parks and Wildlife and Pitkin County Open Space and Trails.
That science team also involves several organizations that are invested in understanding and protecting local ecosystems. The Aspen Center for Environmental Studies, Aspen Global Change Institute, Aspen Valley Land Trust and Roaring Fork Conservancy are all working with WBI.
Tom Cardamone, Executive Director of WBI, said the plan is to continually revisit this science in the field to understand how the habitat is changing.
This study focuses on large mammals, like elk. We see elk all over the valley — are they really at risk now?
There are concerns that you wouldn’t see from the side of the road. Researchers with CPW look at the ratio of calves to adult cow elk in the early winter — the calf:cow ratio — to gauge the health of the herd.
That number has been falling in our area for several decades.
CPW monitors two local herds, called the Avalanche and the Fryingpan herds, and both have seen declines. In the 1970s and 80s, there were nearly 60 calves for every 100 cows; now there are closer to 40.
Researchers also look closely at how many young calves survive to join the herd, called “recruitment.” This number is also declining -- and the trend is not unique to Colorado. Eric Bergman, a researcher at CPW, said in fact, Colorado looks pretty good compared to other western states.
“We still have really, really good recruitment in Colorado,” Bergman said. “It's not like our elk herds are crashing in any way."
But some are declining more sharply than others, including the Avalanche herd. Bergman and others at CPW are looking to understand why.
Do they have any theories?
Julie Mao, a biologist at CPW, said ecological conditions are likely to blame.
It’s not unusual to see a dip in how many calves survive hard winters, but in the past, herds would bounce back quickly. Mao said the Avalanche herd hasn’t recovered since 2007-08, the last really cold, harsh winter in our area.
Mao points to two likely culprits: climate change and a boom in recreation. She said there’s real urgency to preserve the habitat that gives elk the best chance for survival.
“There’s enough indicators that there’s a problem on the landscape that we need to conserve now,” Mao said. “We don’t have time to wait.”
This summer, CPW researchers are starting two new studies that focus on the best ways to minimize the impact of recreation on elk.
What is the focus of this new research on recreation?
Officials with CPW say it’s already known that humans have a negative impact on wildlife. This is why land managers use seasonal closures to keep people out of elk habitat during the most sensitive times of the year, when elk are calving and during the winter.
“Let's all concede: Humans impact wildlife,” Bergman said. “We want to greatly minimize that negative impact, and so what can we do to be better about it."
He said more research can help land managers understand if seasonal closures are working the way they should, and what they might be able to do to improve that balance of recreation and wildlife protection.
One study uses radio collars to track cow elk and their calves, and scientists will be able to watch their movement patterns and see how both the adult animals and their young survive and move.
The other uses new technology with cameras that systematically take photos on set schedules, then run those images through a computer model that analyzes how many animals are using the area. Cameras are set up in Sky Mountain Park and Burnt Mountain, both areas that have seasonal closures near Snowmass Village. Bergman will be able to see how those closures are working and if they might need some tweaking to better serve the elk.