Grand Canyon Program Targets Invasive Species
For decades, vegetation managers at Grand Canyon National Park have been removing invasive, non-native species to preserve and protect the park’s ecosystems and all of the components. While much of that effort has focused on the inner canyon, recently Grand Canyon South Rim has been the main focus of this process.
Park biologists have identified several non-native species such as the tamarisk and the silver leaf nightshade which are invading and crowding native vegetation. Tamarisk- which grows up to 16 feet tall- is easily identified by its wispy foliage composed of small, fleshy leaves and its pink flowers which produce large amounts of seeds. Tamarisk consumes an excessive amount of water and can evaporate up to 300 gallons per day, significantly more than some native plants. Also, the dropped leaves of tamarisk make the soil too salty for most native species to thrive.
Exotics can out-compete native species, change nutrient cycles, and disrupt food chains. Eradicating invasive species is difficult, but can help native species reestablish themselves. Tamarisk and silver leaf can only be removed with chemicals. As a result, the park is using several herbicides rated low in toxicity.
According to Lori Makarick, vegetation program manager at Grand Canyon National Park, the program isn’t designed to return the Grand Canyon to a completely natural state. Instead, it protects it from the most harmful effects of invaders like animal-habitat destruction and wildfire. Makarick also explained that only non-native plants that have the ability to pose a threat to the park’s ecosystems will be targeted. Removal efforts are scheduled to start next month and continue through the fall.