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Mapping Weeds in Griffith Park

CATEGORY: Preservation |
On Jul 17, 2023

Calflora is a non-profit organization that developed a database of California plants that fulfills a huge need for the conservation, education, and appreciation for the state’s incredible plant diversity. Over 10,000 native and introduced species are now captured by qualified contributors, with more than three million geotags which collectively describe each species’ distribution.

Recently Calflora has built a separate specialized system called Weed Manager that has become a successful tool to help agencies and organizations across the state manage invasive plants, by mapping infestations and tracking treatments in real time.

Los Angeles County has embraced the system, and City of LA Sanitation Department’s Biodiversity team encouraged urban park ecologist, Courtney McCammon, to become involved. As a consequence, Courtney and a small trained team of Friends of Griffith Park volunteers are geo-mapping species of concern in the Park. While in the field, data is recorded by drawing spatially on the Weed Manager smartphone app, with input of the species and estimate of the number of plants.

FoGP has been in a constant battle against castor bean, tree tobacco, black mustard, fountain grass and Russian thistle, to name a few. Invasives pose an existential threat to the native flora diversity of Griffith Park, crowding them out of space and zapping the soil of nutrients. Soil disturbance opens a niche for non-natives along every trail, and required brush clearance produces a backlash of more non-natives.

To make matters worse, in recent years there has been a blanket moratorium on the use of all herbicides by City Departments, whereas targeted and limited herbicide use was an effective tool previously.

Mechanical removal can’t solve the entire problem. Interestingly, the County (not the City) lifted its moratorium on herbicides recently, except glyphosate Round-up, — the chemical that caused the controversy in the first place.

~Gerry Hans, FoGP President



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