Rafting on the Colorado River brought almost indescribable joy…
…yet there really was some work involved also.
One stop along the river included Specter Canyon, not a easy place to tie up to.
We waded up into the canyon and heard about the Tamarisk problem from Emily, a seasonal on the vegetation crew.
Tamarisk, also known as salt cedar, comes from Eurasia and was introduced to North America in the 1800s to stabilize river banks. Unfortunately it is a very thirsty plant and can uptake nearly 200 gallons of water a day. Plus it replaces the native vegetation, altering the ecosystem. Tamarisk grows in dense, nearly impenetrable thickets. It also is well-adapted to alkaline, or salty, soils. The soils of the southwest are naturally alkaline, but with the construction of dams, rivers are no longer able to flush salt from the ecosystems and soils are becoming even more alkaline, which deters general plant growth.
For many years the park has tried to use mechanical and chemical controls which include pulling, cutting to stump level and applying herbicide, or girdling to leave the dead tree standing for wildlife habitat. To date crews have removed over 275,000 individual plants from over 6,000 acres. However, these methods rarely kill the plant and often stimulate shrubby re-growth. Now biological controls are taking over. The tamarisk leaf beetle has been tested for 20 years and released in Utah.
Biologists didn’t think the beetle would make it below the 38th parallel, which is near the upper end of Lake Powell. Yet beetle populations have expanded and arrived in the Grand Canyon area without land managers actively releasing them.
The small beetle and its larvae control tamarisk by eating the outer foliage of the plants, thus reducing chlorophyll production and photosynthesis, which reduces the food that is made for the plant. This process should weaken and potentially kill the plant over time. While the demise of this nonnative invader is welcome, it will pose new management challenges such as: how to remove the standing dead trees, how to assess rapid changes in wildlife habitat, and how to successfully restore native plant communities. It is important to understand that ecosystem balance, and not eradication, is the objective when using biological control agents. The goal of the beetle is to control the damage to the ecosystem caused by tamarisk and to prevent its further spread and domination. Ecosystems with beetle populations will never see the case of the last beetle eating the last tamarisk plant.
Bedrock Rapid ~RM131.2
Park resource managers are eager to expand and develop new partnerships with other federal land management agencies and organizations to assist with the development of long-term plans to restore native ecosystems in the Colorado River corridor both within and outside park boundaries. Commercial and private river trips enjoying rapids like this will be a part of the plan. If you would like to volunteer to help with this effort, please contact Grand Canyon Trust.
After this bit of work we continued down the river to Deer Creek Falls.
