Showing posts with label invasive species. Show all posts
Showing posts with label invasive species. Show all posts

October 22, 2015

Could We Have a Natural Control for Horrible Cheatgrass?

A cheatgrass monoculture (Bureau of Land Management).
If it were possible, I would nominate these scientists for a prize.
Now, some 65 years after famed naturalist Aldo Leopold summed up the general consensus in the battle against cheatgrass as hopeless, there might be hope.

"We're in a better position to fight back than we have ever been," said Susan Meyer, a U.S. Forest Service research ecologist working with fungus at the Shrub Sciences Laboratory in Provo, Utah.
 Why is cheatgrass a Bad Thing?

• It comes up early in the spring. At that point it is soft and green. It looks good to eat, hence the "cheat" part.

• But very soon it sets its seeds in horrible, prickly awns that hurt grazing animals' mouths, puncture people's shoes and socks, catch in other animals' coats, and spread wherever they are  carried. 
In addition to being a wildfire threat and an ecological problem, cheatgrass can harm animals. Its stiff, spiny seedheads, called awns, can work their way into the ears, eyes or mouths of everything from cats to cattle.
• Because it dries out early in the summer, it carries fire easily.
The keys to cheatgrass spread are its short life cycle and prolific seed production. Because cheatgrass stands dry out by mid-June, fires are more likely to occur earlier in the season. These mid-summer fires are tough on native forbs and grasses.
Cheatgrass seeds drop prior to fires and will germinate with fall precipitation. This gives rise to dense, continuous stands that make additional fire ignition and spread more likely. Fire return intervals have gone from between 60–110 years in sagebrush-dominated systems to less than 5 years under cheatgrass dominance. With every reoccurring fire, cheatgrass becomes more dominant and expands its range further. 
• It has damged the West by reducing feed for both wildlife (elk, deer, pronghorn antelope) and domestic animals:  
“Cheatgrass has probably created the greatest ecological change in the western United States of anything we’ve ever done,” said Steve Monsen, a retired Forest Service botanist in Utah who conducts research for the agency.
It can be grazed when young and green, but unlike native perennial grasses, it does not "cure" on the stem for winter consumption.

On my own little patch of Colorado, I watched cheatgrass move from roadsides, seemingly leap over healthier pastures, and appear in groves of pines trees.

So what Is the new development?

There are pesticides that work against cheatgrass, but the invasion is too big to spray it all. Susan Mayer and others are looking at bacteria instead:
Meyer and Ann Kennedy, a scientist in Washington state working with bacteria, are drawing attention from top land managers and policy makers — and research money — after showing that the seemingly invincible cheatgrass might have an Achilles' heel. 
"We've found several organisms that are really good at colonizing the root of the seed, and reducing the elongation of that root," said Kennedy, who works at Washington State University. "Then that cheatgrass is less competitive the next spring."
This will all cost a whole lot of money. But isn't the West worth it?

June 14, 2014

Primroses, Wild Mustard, and Homiletics

Having a sort-of average spring after several dry years means seeing old friends, plus some plants we regard with suspicion.

Cutleaf primose scattered in pasture.
I mentioned the purple/blue mustard. They were succeeded in May by cutleaf (or prairie) primroses—not the huge banks of them sometimes seen on the remaining High Plains grasslands, like Pawnee National Grasslands, but a lot for us.
Cutleaf evening primose, Oenothera coronopifolia
Here is a close-up —these were a little shredded by hail on the previous day.

They have been followed by a yellow-flowered wild mustard that has a sort of rotting-soap smell (or "stale dishrag") when stepped or driven upon. It looks like this one: Sinapis arvensis, but the distribution map does not show it in Colorado. Maybe a relative? Can't mow it all to stop the seeding, so it will be back when conditions are right.

Or as the gospel says, "But when it is grown, it is greater than the herbs, and becomes a tree, so that the birds of the air come and lodge in its branches."

If preachers ever interacted with the natural world, they might dust off their sermons on the parable of the mustard seed this year. People could visualize it.

July 31, 2012

Fighting Cheatgrass with Fungus

Whoever can stop cheatgrass deserves a Nobel prize and the thanks of a grateful continent.  A fungus holds some promise.
“Cheatgrass is a very insidious kind of biotic virus,” said Stephen Pyne, a Western fire historian at Arizona State University. “It takes over and rewrites the operating system. Because it grows earlier, it can burn earlier,” then in its regrowth “drive off all the other competitors. That makes for a complete overthrow of the system.” 

Mike Styler, head of the Utah Department of Natural Resources, said simply: “It’s changed the entire ecology of the West.” 

But the black fingers of death — Pyrenophora semeniperda — may help restoration ecologists like Dr. Meyer reclaim some beachheads in the vast swath of land already conquered by cheatgrass.
I have been seeing it a lot more around here lately, thanks to two drought years in a row, which just makes me sick to contemplate.