The Great Abandonment

[Silver]

Here the big transition is in the plant community. It has been cause by fire suppression. Historically sagebrush was very rare or non existent. Juniper was limited crags and rocky slopes. The naturally caused fires would run across the grass lands quickly just burning of the above ground portion of the grass. The woody brush species would die where as the grass would rebound back up. Now there are areas with miles of either sagebrush or in some cases juniper. The big junipers thickets don't burn well because they choke out every thing under the trees. Which doesn't allow a hot enough fire to burn up into the trees.

Lack of fire causes very similar problems here, and our environment is very different from yours.

 

[Dave]

You can drive down the highway and see where there has been fires. Just grass with no sagebrush. A mile down the road it will have thick sage. It takes a lot of years for the sage to invade back into those fire areas. The only real effective control method is fire. Some controlled burns are used but the issue is keeping them under control. There is a fine line between this stuff will spread too easy and it takes a flame thrower to get a fire started. And of course government prosecution of some rancher who burned a little BLM ground has people nervous about starting a controlled burn.

 

[Logan52]

They say much of the bluegrass land around Lexington was originally a Savannah type grassland interspersed by large Burr Oak and Blue Ash trees. Large herds of buffalo and their grazing maintained this condition and were essential to it.
Where I live on Sugar Creek, a deeply dissected north facing drainage, it was damper and there were near solid stands of Sugar Maples and wild cane brakes.
The marl hills to the south were drier and devoid of trees. Indians regularly burned them to provide grazing for buffalo and elk. Early settlers called them the "Bald Hills", but today they are covered with solid stands of Red Cedar.

Today, these distinctive ecosystems all grow up in multiflora rose and bush honeysuckle when abandoned.
The Nature Conservancy bought up hundreds of acres along the Kentucky River palisades and tried to recreate the old ecosystems. Without grazing large herbivores and the Indians annual burning, they found it impossible to do so.

 

[chevytaHOE5674]

Lack of fire causes very similar problems here, and our environment is very different from yours.

Same here it was frequent low intensity fires that burned off the grass, small underbrush, and dead fall. But decades of fire suppression has now caused a buildup of brushy thick dense understory that chokes out almost everything.

 

[Mark Reynolds]

Interesting to read these. There is not really one cause for ecosystem shifts, and that is what these are. "Succession" is what I learned at Purdue and in elementary and high school. I learned about the state and transition models a few years later at Oregon State. The ecosystems in the east are a lot more resilient to change and 'succession' can be expected to take place. Succession does in the west as well, but the ecosystems are much more 'brittle' and come with thresholds. When a threshold is crossed, succession is broken and it requires a tremendous amount of input of resources to return an ecosystem to what it was formerly, and it often can't be done at all.

There are multiple 'culprits' for the ecosystem shifts. Plowing native prairie or savana or sagebrush steppe, large scale logging, lack of fire, removal of wildlife species/extinctions, introduction of non-native and invasive species, climate shifts or climate destabilization (climate 'change' is too political to use, and there is a dark difference between change, shift and destabilization). Most people see these changes on a limited, local scale. The variety told here gives a glimpse of how widespread these changes are. Good or bad, my career has taken me many different places where I can observe these effects first hand in conjunction with my career.