Vital coast prairies in growing jeopardy

ACCELERATING DECLINE In the sample shown above, the grassland prairie shrank 38 percent in 64 years from 1941 to 2005, and 52 percent in 11 years from 2005 to 2016. Overall, this area has dwindled 70 percent over 75 years. The rate of loss is faster now because the increased edge effect of encroachment is closing in on the remaining open space in many areas. Image courtesy Bureau of Land Management

Paul Mann
Mad River Union

MCKINLEYVILLE — The North Coast’s ecologically essential grasslands are continuing to shrink at a rapid rate that requires a new fire management strategy, scientists say.

In the 64 years between 1941 and 2005 coastal grasslands shrank by 32-40 percent, a loss of some 1,630 acres, according to the Arcata field office of the Bureau of Land Management.

Most coastal grasslands have continued to shrink in area since 2005, with an estimated reduction of 50 percent as of today.One area of the King Range Wilderness has shrunk an extraordinary 70 percent in the past 75 years and the contraction is accelerating.

Scientists say the gremlin is California’s 100-year history of total fire suppression.

What would help are carefully controlled, low-intensity burns. They would eliminate vast quantities of forest floor duff and detritus that fuel catastrophic wildfires, while at the same time clear out the woody shrubs and encroaching trees that hamper and obstruct the growth of perennial bunchgrasses.

Thriving perennials are crucial to the North Coast’s healthy prairies and their wildlife ecology, says veteran botanist and range conservationist Jennifer Wheeler of the Bureau of Land Management’s Arcata office. In the last five years, she says, the bureau has reclaimed approximately 330 acres of grassland that were lost to recent woody vegetation encroachment.

Those 330 acres are only a fraction, however, of the some 7,000 acres of North Coast grasslands managed by the bureau.

They are declining, Wheeler said in an interview, owing to the lack of what she calls disturbance: prairies need to be burned, grazed or mechanically/manually tended if they are to be reclaimed from the shrubs and trees that infiltrate and invade them.

“It’s important to have a mosaic of all the habitat types because wildlife depends upon grasslands, as do humans,” she explained. “That drives the terrestrial food system. The grasslands are a prey base for raptors, carnivores, hunters and trappers.”

The reintroduction of native, perennial bunchgrasses provides a host of ecological benefits: diverse species composition, deeper root systems, better water filtration to lower depths, improved air flow and soil stability, reduced susceptibility to invasive species, stronger toleration of drought and greater fire resistance.

The worsening grassland decline therefore represents a major ecological setback.

“Grassland areas are being lost to the encroachment of shrubby vegetation, like berry brambles, coyote brush (a shrub in the daisy family) and Douglas fir,” says Wheeler. “Even little wild grasslands on which rabbits, gophers and snakes are so dependent are losing their habitat.”

In a presentation at the McKinleyville Land Trust’s recent annual fundraiser, Wheeler said the field office has planted 400,000 perennial bunch grass plugs since 2008, spanning some 250 acres of small coastal prairies.

The plugs comprise 14 native grass species and many forbs (from the Greek phorbs) which are herbaceous, flowering non-woody plants, as distinct from grasses, sedges and rushes. Examples include clover, sunflowers and daylilies.

The bureau plantings are progress but they come with an important caveat, Wheeler points out. “We augment the composition but we don’t enlarge the area. That doesn’t mean every square foot is occupied, it means a colony has been placed and it influences an indeterminate area around it,” possibly 400 acres in all.

Normally, 500 plugs are planted per colony, with about 800 colonies established so far; they constitute material progress but are well behind the rate at which local grasslands are shrinking.

“I don’t think we’re going to reverse the trend unless somehow we embrace fire in our culture. I’m holding on to the biodiversity and  helping pollinators and wildlife that are dependent on prairie grasslands, but I don’t think we’re going to change it back wholesale to what it was.”

She adds, “On the other hand, I don’t think it’s a losing battle. In the King Range [National Conservation Area in southern Humboldt] there was maybe one prairie’s June grass left. We’re still making substantial progress and we’re using local plant material that comes from the King Range and is used in the King Range. We’re enhancing those native populations. Overall, we've treated about 6% of the grasslands within the field office through reclamation and enhancement so far, and we expect to continue to expand on these efforts.”

Wheeler says organizations like the McKinleyville Land Trust can play an important role in expanding public knowledge of the grasslands crisis, knowledge that is “highly lacking.” People tend to visualize the prairies as an abstraction—“all grasses are the same.” Bunch grass biology is not taught in high school or even in junior college and she first learned about it in an undergraduate, upper division rangeland resource science course at Humboldt State University, where she earned her degree in 1993. “Unless you have a really keen interest in rangeland landscapes, I don’t think you get that education.”

Land trusts can install interpretive panels along trails to enlarge public awareness, set up discussion panels about the ecological benefits of grasslands to pollinators and wildlife and plant small scale colonies of Idaho fescue, prairie June grass and other species, she said.

Public education is also crucial to changing the attitudes of property owners, large and small, toward fire, forestry experts say. Reversing policy from total suppression to controlled burns means addressing deeply instilled popular fears of forest fires. Those apprehensions will have to be counterbalanced with the spread of less well-known information about the ecological and safety benefits of prescribed blazes.

 







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