- Associated Press - Saturday, February 7, 2015

GRAND JUNCTION, Colo. (AP) - The West’s “sagebrush sea” has gotten a lot of attention recently for supporting some 350 species of plants and animals, with the future of creatures from mule deer to greater sage-grouse inextricably linked to this habitat on which they rely.

Now increasing research, including a new study by a Grand Junction couple, is finding that this sea is populated with countless islands of soil fertility typically associated with sagebrush plants themselves.

The study by Tamera Minnick and Richard Alward additionally found those islands to be lacking on former oil and gas well pads sampled in Rio Blanco County - a discovery that could help guide how pads are reclaimed in the future.

The couple’s findings came only after long, hard hours of digging in the dirt with the help of undergraduate students, followed by lab analysis of soil samples and writing a paper that was published last week in the January issue of Ecological Applications.

“It’s really rewarding when you get to the end and get something out like this that we can both say, ‘Yeah, we did this,’ ” Alward said.

“I don’t think I could have done it without him,” said Minnick.

The two are plant ecologists. Minnick is a professor of environmental science at Colorado Mesa University, and Alward is an ecological consultant whose clients include the oil and gas industry. He also serves on the Colorado Oil and Gas Conservation Commission.

Their work, made possible in part by a grant of almost $94,000 by ExxonMobil, involved soil sampling on eight reclaimed or abandoned oil and gas pads dating from the 1960s to 2008 on Bureau of Land Management land in Rio Blanco County.

Samples also were taken at two nearby reference sites designed to indicate pre-drilling soil conditions. The sampling was done in 2009 with the help of some then-undergraduates at CMU.

The research was designed to build on past research finding that trees and shrubs can create “resource islands” in the soil beneath them. This is because of things like moisture running down stems, and decay of roots and fallen leaves, and of dead insects and other particles that are captured in branches and foliage and fall to the ground.

“The shrubs modify their environment. They engineer it to be better for them,” Alward said.

In the case of sagebrush, its root system also extends horizontally underground well beyond the radius of the sagebrush canopy itself, extracting water and nutrients so it’s not available to other plants nearby.

Research had found elsewhere that all of this contributed to patchy patterns of enriched soil in other sagebrush country, and Minnick and Alward first confirmed that this also was the case at their reference sites. Such enriched soil can contribute to growth of new sagebrush as old plants die off, and to growth of a more diverse mix of other vegetation as well.

The researchers’ next step was to determine whether islands of enriched soil had re-established themselves on ground where soil had been scraped off and mixed together when oil and gas pads were created.

“What we’ve shown with this is that even with a well pad that’s had 47 years to recover, the soils were still mostly in that homogenized state,” Alward said.

The finding could be important because state and BLM reclamation requirements for well pads “only talk about plant cover. They don’t talk about soils,” he said.

“Soil recovery indicates that we’ve got a functioning ecosystem again, not just some plant cover. We don’t just have a garden but we actually have an ecosystem that can support diverse wildlife.”

“. If you’re concerned about recovering wildlife, then you need an ecosystem that is self-regenerating and we did not find any evidence for that (at the studied sites).”

The oil and gas conservation commission says a reclaimed area should contain grass, forbes and shrubs reflecting what’s at an undisturbed reference site, Alward said. But he said his and Minnick’s study found that not all shrubs are alike.

“Sagebrush engineers its own unique ecosystem. Rabbitbrush does not serve the same function,” he said.

That’s in part because rabbitbrush root systems don’t extend laterally much beyond the plant’s canopy radius.

“You could theoretically have a well pad with a 30 percent shrub cover, and if it’s all rabbitbrush it is not recovered as a sagebrush ecosystem,” Alward said.

Minnick said the study shows the need to get shrubs, especially sagebrush, re-established in reclamation. There can be a challenge in doing that when often a reclamation goal is simply to get vegetation growing on bare ground to prevent problems such as erosion and outbreak of weeds.

“It’s a lot easier to get grasses established and to manage them than it is to have a diverse ecosystem,” Minnick said.

Alward said ensuring that some sagebrush seed is used during reclamation is a good starting point. Also, at the reclamation stage, well pads can be intentionally made uneven with pockmarks, and woody slash that was removed during pad creation can be put back in piles rather than being evenly distributed. The piles and pockmarks can capture and provide nutrients and moisture and serve as sites for shrubs to start growing.

He said that some oil and gas companies “are already doing a lot of this.”

“The one thing our study says is, it’s worth that extra effort. If you want to reclaim habitat and help prevent listing of sage-grouse, then it’s important to not only do that extra effort but document that you’ve done it.”

The U.S. Fish and Wildlife Service is currently considering whether the greater sage-grouse should be listed for protection under the Endangered Species Act in Colorado and other western states.

“If your goal is a functioning ecosystem, it’s worth taking those extra (reclamation) steps, and in areas that support sage-grouse and mule deer and elk, golden eagles and pygmy rabbits, I think it’s worth the effort,” Alward said.


Information from: The Daily Sentinel, https://www.gjsentinel.com

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