Tuesday, September 28, 2021

There's snakes in them Painted Hills!

Painted Hills
The Painted Hills unit of the John Day Fossils Bed monument in Oregon is a beautiful landscape, filled with multi-colored hills that are a testament to the changing environmental conditions in the area over millions of years. But almost hidden among the ground cover is the same hegemonic grass species that is rapidly spreading in the Great Basin.

Medusahead seedheads rise above the surrounding ground cover
We spent a few hours in the park and hiked the five major trails. In all of the trails I found clusters of Taeniatherum caput-medusae. Some trails had only isolated small groups, but others had thousands of individual plants. The species was also relatively easy to identify, with the seedheads sporting twisted awns that made it seem like the head of the fabled Medusa.

It was even possible to determine larger clusters of the species from a distance. The dried grass formed a very dense looking golden mass, which stood out very clearly from the surrounding darker colored ground.

The carpet of medusahead was easy to distinguish on the desert floor
The carpet of medusahead grass serves as a foreground to the beautiful hills

When I moved closer to examine the golden carpet, I found dense thatches of medusahead, the individual plants so close to each other that they formed an almost impenetrable barrier to other species. T. caput-medusae has a very high silica content (which makes it unpalatable to grazing animals for much of its life cycle, with grazing capacities reduced by as much as 80 to 90%), and the thatch is not only slow to degrade but is also a source of fine fuels for any fire. These attributes contribute to its continued spread and dominance over existing plants in an area. 

Dense thatch of medusahead in Painted Hills
The Painted Hills is undoubtedly gorgeous, and this beauty is enhanced by the natural flora that surrounds the hills, whether it be the trees or the sagebrush or the bunch grasses and associated forbs. The continued encroachment and spread of T. caput-medusae in this protected environment would tarnish that beauty and result in a monotypic community that is also very fire-prone.


  1. I lived in Oregon for 15 years and the state was my playground during a very happy part of my life. I grieve for that wonderful site, the Steens, and so many places...but mostly for the prong and sage grouse.

    1. The sage grouse is definitely being affected by the spread of these invasives. Hopefully, there will be a way to protect their habitat, or at least maintain areas where it is possible to control the invaders.