For the last 10 years, Western Ecosystems Technology, Inc. -- an environmental and statistical consulting group -- has been studying the mule deer that winter on the Pinedale Anticline. Over the first four years of the study,
But the latest data, just released in a new report [pdf], makes those increases look like a temporary distraction from an overall downward trend. From 2008 to 2009 the Anticline’s mule deer population plunged by 1,700 – a 45 percent drop in just one year, and the lowest population documented in the course of the study.
Here's what we know:
- In the last 12 months, 754 natural gas wells have been drilled on the Pinedale Anticline.
- Mule deer avoid natural gas well pads.
- Mule deer on the Anticline have decreased by 60 percent since the gas boom started.
And here's what we don't know:
- Whether gas drilling is to blame for the mule deer decline.
- What to do next.
Mule deer are declining throughout the West, according to Miles Moretti, president of the Mule Deer Foundation. "The biggest pressure on mule deer is loss of winter range," he says. "I don't know why, but it seems that every place there is winter range there is oil and gas."
Still, the authors of the report, caution against attributing the declines on the Anticline exclusively to natural gas development. They suggest that a series of unusually mild winters combined with winter off-road vehicle restrictions in surrounding areas could have caused mule deer to seek other winter range. However, they add that increased drilling activity may have disrupted fawn survival or adult reproduction.
BLM officials, wildlife experts and industry representatives got together to discuss the mule deer data at a public meeting in Pinedale on October 27. Biologist and report author Hall Sawyer explained it's not just the number of mule deer that's going down, but their survival rate as well. During the study, some deer died in early May due to poor body condition. "Survival is as low as we've ever seen it," Sawyer said. "It certainly raises a red flag."
According to the Bureau of Land Management's development plan [pdf] for the Anticline, a 15 percent decline in mule deer will trigger serious mitigation measures, which could include on-site habitat enhancement, protecting habitat in surrounding areas, through conservation easements, for instance, or modifying operations on the Anticline.
BLM Pinedale Field Manager Shane DeForest says his agency "predicted there would be substantial impacts from development." He feels the report offers validation that adaptive management -- a process where managers monitor wildlife as development goes forward and adjust operations along the way based on how they respond -- is working as it was intended. "It is meant to be a living process," he says, explaining that the next step is to design and implement mitigation measures. The BLM is accepting public input on mitigation through November 3. Comments should focus on specific actions the BLM can take to protect mule deer and can be sent to email@example.com. Next, the BLM will meet with the Wyoming Game and Fish Department and industry representatives to come up with a mitigation plan, which they intend to unveil at a public meeting after the Christmas holiday.
Others believe the 2009 data simply shows natural variation. "Continuing monitoring is needed,” industry representative Tim Murray said at the recent Pinedale meeting, according to the Casper Star Tribune. “Let's see what the results are before we start reacting too much.'"
Emilene Ostlind is a High Country News editorial intern.
Mule deer photo used with permission from Mark Gocke. Data in chart from "Mule Deer Monitoring in the Pinedale Anticline Project Area: 2010 Annual Report," by Hall Sawyer and Ryan Nielson of Western Ecosystems Technology, Inc.