Invasive Plant Species

Russian Thistle, an invasive species at the park.

NPS photo.

Managing Invasive Plants at Cabrillo National Monument

Invasive plants are species that have been introduced into Cabrillo National Monument, either purposefully as ornamentals or accidentally through means like boots, car tires, and other vectors. These non-native plants thrive so well in their new environment that they rapidly spread, out-competing native plant populations. This aggressive growth is why park staff and volunteers work diligently to remove invasive plants from the park.

If allowed to grow and reproduce unchecked, invasive plants can quickly deplete resources that native plants need to survive. In addition to outcompeting native flora, invasive species can increase fire frequency (a common issue with many European grass invasions), eliminate valuable food sources for native animals, and facilitate the invasion of other non-native plants.

Cabrillo staff and volunteers are dedicated to removing invasive species throughout the park to protect and preserve the native ecosystem.

 

Understanding Invasive Plants

Invasive plants are species that have been introduced into environments outside of their native range, either purposefully (as ornamentals) or accidentally (via boots, car tires, etc.). These plants are non-native and have the ability to thrive exceptionally well in their new environment, to the extent that they rapidly spread and begin to outcompete native plant populations. This aggressive growth can lead to significant ecological imbalances and poses a serious threat to biodiversity.

Impact of Invasive Plants

Competition with Native Plants

Invasive plants can outcompete native plants for essential resources such as sunlight, water, and nutrients. This competition often results in the decline or even extinction of native plant species, leading to a loss of biodiversity and altering the natural habitat.

Increased Fire Frequency

Certain invasive species, particularly many European grasses, can increase the frequency and intensity of wildfires. These plants often grow densely and dry out quickly, providing ample fuel for fires. Increased fire frequency can further damage native plant communities and alter the landscape.

Disruption of Food Sources

Invasive plants can disrupt the food web by eliminating or reducing the availability of valuable food sources for native animals. This can have cascading effects on the entire ecosystem, affecting not only plants and herbivores but also the predators that rely on them.

Facilitation of Other Invasive Species

Invasive plants can create conditions that facilitate the invasion of other non-native species. For example, they can alter soil chemistry or hydrology, making it easier for other invasive plants or animals to establish and spread.

Management and Removal Efforts

Cabrillo National Monument staff and volunteers are actively engaged in managing and removing invasive species throughout the park. These efforts are crucial to protecting the park’s native ecosystems and ensuring the survival of native plant and animal species. Management strategies include:

• Physical Removal: Manually pulling or digging out invasive plants, especially those with shallow root systems.
• Chemical Control: Using herbicides selectively to target invasive species while minimizing impact on native plants.
• Biological Control: Introducing natural predators or pathogens that specifically target invasive species, helping to control their populations.
• Monitoring and Research: Continuously monitoring the presence and spread of invasive species and conducting research to improve management techniques.

How You Can Help

Visitors to Cabrillo National Monument can also play a role in preventing the spread of invasive species:

• Clean Your Gear: Before entering and leaving the park, clean your boots, clothing, and gear to remove any seeds or plant material.
• Stay on Designated Trails: Avoid straying off designated paths to minimize the risk of spreading invasive plant seeds.
• Report Sightings: If you spot any invasive plants while visiting the park, report them to park staff so they can take appropriate action.
• Volunteer: Join the park's volunteer program to assist in the removal of invasive species and other conservation efforts.

By working together, we can protect Cabrillo National Monument's unique ecosystems and preserve its natural beauty for future generations.