slender false brome

Integrated Pest Management (IPM) is a method for managing plant and animal pests while protecting human health and the environment. The District has adopted an IPM Guidance Manual to direct its management of harmful invasive plants, invasive animals, and weeds on preserves; flammable vegetation near facilities; and rodents and insects in District-owned buildings. Under IPM, District staff make sure they understand the biology of the pests, chemical and non-chemical options for controlling them, and any secondary effects of the control techniques (soil erosion, pesticide drift, and bioaccumulation). Non-chemical techniques to control pests (prevention, cutting, digging, mowing, traps) are considered before chemical methods (pesticides, herbicides, insecticides). An Environmental Impact Report has been prepared on the IPM Program.

2015 Annual IPM Report

This report presents the results of the first year of pest management activities prescribed under the Midpen Integrated Pest Management (IPM) Program.  The District treated thirty-one species, including twelve listed noxious weeds (plants that have been defined as a pest by state law or regulation) using a variety of treatment methods. Treatment methods that included the use of chemicals, did so using only Board approved chemicals.  

Download Report

Bear Creek Redwoods Open Space Preserve Integrated Pest Plant Management

A plan has been developed for the prevention, detection, and control of priority invasive plant species impacting the Bear Creek Redwoods Open Space Preserve. This preserve is being prepared for public access. Part of the preparation includes managing invasive plant species so that pre-opening construction and future public use does not spread invasive plants and create a larger management problem, and so that the District has a strategy to proactively manage invasive plant species in the Preserve.

Download Plan 

Invasive Species Control

An invasive species is a plant or animal species that invades portions of the local ecosystem, takes over large areas, and reduces biodiversity in ways that often cause economic or environmental harm. The District removes invasive species from its preserves whenever possible.

The District follows a strategic plan when dealing with invasive species. When weedy plant species are located, their potential for becoming invasive at that location is evaluated. Of particular concern are invasive plants that will threaten rare native species or are likely to spread rapidly or cover large areas. A new sighting is added to a priority-based list for work by District staff, volunteers or contractors. District staff researches the best methods to control an invasive species using an integrated pest control approach, and makes certain to return to a site as many times as necessary in subsequent years to first contain the spread of the invasive plant and then eradicate it completely from that site. Regeneration of native plants is encouraged at the control site, or native plants are seeded or planted.

Stinkwort

A rapidly spreading non-native invasive species, Stinkwort (Dittrichia graveolens), has been identified in Midpen preserves spreading to trails, grazing lands and serpentine soils. The plant is poisonous to livestock and touching can cause skin itchiness or blistering.

Identification:

  • Sticky, gummy leaves with powerful aroma of camphor
  • Light green, thin linear leaves
  • Small yellow flowers and fluffy seed heads
  • Mature plants spread into a “bushy beach ball” shape, up to 3 feet tall

If seen, please record in the iNaturalist app or contact Tom Reyes, Integrated Pest Management Coordinator at (650) 691-1200.

Download Stinkwort Information

Feral Pigs

Since 2000, the District has been trapping feral pigs in the South Skyline and Sierra Azul regions. Feral pigs root up hillsides with their snouts, disturb plants, cause erosion, dig up wetlands, and eat acorns and other food sources so that less food is available to native wildlife. The trapping program, conducted in coordination with surrounding landowners and park districts, has greatly reduced the population of and damage caused by feral pigs.

Slender False Brome

A new and potentially destructive invasive species, slender false brome (Brachypodium sylvaticum), has been found in the Woodside area, including Thornewood Open Space Preserve. A perennial bunch grass originally from Europe, Asia, and North Africa, it is capable of achieving over 90% ground cover, inhibiting the growth of tree seedlings, and completely replacing native vegetation.

In Oregon, this invasive grass has spread to over 10,000 acres and has become a major resource management problem. Slender false brome was identified in Woodside in January 2004. This area is the only known location of the weed in California. It is important that the problem is taken care of quickly before it spreads and becomes unmanageable.

Slender False Brome Ten Year Status Report

For more information, please visit the District Slender False Brome page.

Sudden Oak Death

Sudden Oak Death (SOD) is a forest disease caused by the fungus-like pathogen Phytophthora ramorum. The pathogen has caused the widespread dieback of some oak species and other plants commonly found in oak forests in Northern and Central California, including some District preserves. The pathogen causes cankers to grow on the leaves or wood of infected plants. Consequently, other pest organisms like fungi and bark beetles can eventually kill an infected tree. How the pathogen spreads is currently unknown, but it appears to be associated with moist winds, especially around California bay trees. It may also be spread by moving infected vegetation and soil, including material accidentally carried by shoes and tires.

In 2005, the District committed $350,000 over 10 years to find ways to prevent and treat Sudden Oak Death by working to identify resistant trees, preventing infection of heritage trees, and participating in collaborative research.  In 2006, the District began working closely with the California Oak Mortality Task Force (COMTF) to achieve these goals. The District partners with scientists on SOD research projects to better understand how to manage the preserves in light of this spreading disease.

The combined results of all these studies will help the District prevent the spread of Sudden Oak Death for the safety of its visitors, health of the environment, and protection of California’s trees.

Sudden Oak Death Ten Year Update

In the meantime, District staff continues to monitor the preserves for symptoms of Sudden Oak Death and to work with representatives from the COMTF to stay abreast of the latest science and news regarding the spread and control of the pathogen. The District follows “clean practices” when working in Sudden Oak Death areas to control its spread into new areas. Closures of certain trails during the rainy season may also assist in controlling its spread.

To prevent the unintentional spread of Sudden Oak Death (remove soil and vegetation), educational materials and signs are posted at open space preserves with high-risk areas for Sudden Oak Death to encourage visitors to stay on trails and to clean their shoes, pet’s paws, and tires before leaving the preserve. Please take note of these signs when visiting District preserves.

For more information, visit the California Oak Mortality Task Force.

Rodenticides

By 2013, scientific research was suggesting strong evidence that commonly-available pesticides called second-generation anticoagulant rodenticides (SGARs) were harming wildlife throughout California, and linked to the illness and death of many bobcats in our preserves.

Predators like bobcats, hawks, and owls can eat hundreds of mice and rats a year, and when predators eat rodents that have consumed SGAR pesticides, the toxins can accumulate and cause diseases such as notoedric mange. This disease weakens the immune system in felines, causing them to become feeble and emaciated.

After numerous sick animals were observed in the preserves, Midpen staff educated preserve neighbors about the effects of SGAR rodenticides on wildlife and joined the ongoing effort to lobby the California State Legislature in prohibiting their use. In 2014, the legislature passed AB 2657, limiting access to SGARs to individuals with state-issued pest control licenses. Midpen also took action with its IPM Program, using non-chemical techniques whenever possible to protect human and environmental health.

In recent years, there have been indications that bobcat populations in the preserves are now healthier, and have not been observed with signs of notoedric mange. However, some anticoagulant rodenticides are still readily available in California, which, if used irresponsibly, could continue to threaten wildlife. Midpen continues to work with other agencies and organizations to ban SGAR rodenticides and promote alternative pest control methods.

How can you help? Harden your home against rodents by removing ivy and fallen fruit, patching holes in buildings and not leaving pet food out. When active pest control is necessary, consider non-chemical methods such as snap and box traps to control rodent populations in your neighborhood.

Rodenticide resources:

IPM Coordination Team

The IPM Coordination team is multidisciplinary team made of District staff led by the IPM Coordinator, Tom Reyes.  The team includes:

  • Michael Bankosh, Maintenance Supervisor
  • Jean Chung, Property Management Specialist
  • Steve Davidson, Open Space Technician
  • Brendan Dolan, Maintenance Supervisor
  • Brian Fair, Open Space Technician
  • Ellen Gartside, Volunteer Program Lead (Restoration Ecology)
  • Amanda Mills, Resource Management Specialist II (Restoration Ecology)
  • Coty Sifuentes-Winter, Senior Resource Management Specialist (Vegetation Ecology)

See a plant out of place?  Let the District know the species using iNaturalist, a free citizen science app, or e-mail Tom Reyes at treyes@openspace.org.