No one wants to see weeds instead of wildflowers when they visit Yosemite. Yet non-native invasive plants are the single largest threat to Yosemite plant life. 

These invasive plants replace native species and disrupt ecosystems, including birds and animals that depend on native plants for food and shelter. Every year brings new invaders, with over 200 currently identified—30 in the past three years alone.

This project was the first comprehensive mapping of invasive species in the park. Websites and iPod Touch GPS units helped coordinate efforts between staff, volunteers and encouraged ‘citizen scientists’.

Using the survey data, invasive plants can now be quickly identified and eliminated. This information also helped develop a podcast that teaches visitors about the negative impact of bringing outside firewood (and invasive weeds) into the park.

Working together we can protect Yosemite’s beautiful wildflowers.

Partnering with Yosemite National Park

Garrett Dickman


Project Notes

Himalayan blackberry has displaced more than 100 acres of native vegetation in meadow and riparian areas with high plant and animal diversity. Yellow star thistle has displaced many native plants, reduced the food supply for wild animals  â€” the sharp spines stop hikers from even walking through it.