The Hidden Impact of Invasive Species at Santa Margarita River Trail Preserve
Arundo donax, invasive plant at Santa Margarita River Trail Preserve
Nestled in San Diego County, the Santa Margarita River Trail Preserve is one of Southern California’s last untouched ecosystems. Spanning 18 miles of scenic trails, it’s home to nearly 1,000 species of plants and animals, making it an essential part of the South Coast Ecoregion — one of the world’s biodiversity hotspots.
But despite its beauty, the Preserve faces an urgent threat: invasive species.
The Santa Margarita River is the last free-flowing river in Southern California, providing vital habitat for native wildlife. Its riparian and upland ecosystems support species like the endangered California gnatcatcher and arroyo toad. However, non-native plants such as black mustard (Brassica nigra), Malta starthistle (Centaurea melitensis), and arundo (Arundo donax) are rapidly taking over. These invasive species crowd out native plants, disrupt wildlife habitats, and alter the landscape.
Species like black mustard and starthistle have spread across the eastern parts of the Preserve, while tree tobacco (Nicotiana glauca), arundo (Arundo donax) and tamarisk (Tamarix ramosissima) dominate patches of the river floodplains. These invaders outcompete native vegetation and threaten the balance of the ecosystem.
Combatting Invasive Species: Wildlands’ Strategy for Restoration
Addressing the invasive species problem at Santa Margarita River Trail Preserve requires collaboration, persistence, and innovative strategies. The Wildlands Conservancy, in partnership with dedicated volunteers and organizations like the Fallbrook Trails Council, is committed to restoring the Preserve’s health.
Each year, the team tackles invasive plants using a variety of methods. String trimmers clear black mustard and starthistle from trails, while volunteers hand-pull these plants from oak woodland restoration areas. Along the river, hand saws are used to cut tree tobacco, and brush-on herbicide prevents further spread. Wildlands is also focused on removing tamarisk and arundo, which threaten the floodplain ecosystem and native tree growth.
Volunteers Make a Difference
Volunteers are essential to the success of these restoration efforts. In recent years, the Fallbrook Trails Council has organized successful community workdays, where locals come together to clear weeds and restore trails. Volunteers also help protect newly restored areas near the Willow Glen Trailhead, ensuring that native plants have space to thrive.
As Wildlands’ South Coast Regional Director, Zach Kantor-Anaya, shares:
"As long as we are persistent and have the human power to maintain areas, we can turn the tide on these invasive plants. This is where volunteers can make a huge impact."
Get Involved
The Santa Margarita River Trail Preserve is a fragile ecosystem that needs our collective protection. By volunteering, spreading awareness about invasive species, or simply visiting and enjoying the Preserve, you can play a key role in its future.
Every action counts in preserving this Southern California treasure. Whether you volunteer, visit, or share the message, your involvement helps ensure that the Santa Margarita River Trail Preserve remains a vibrant and thriving habitat for generations to come.
Santa Margarita River Trail Preserve, San Diego County