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Tapping Crowds to Track California’s Weeds

Help map the spread of invasive plants with a smartphone app

Jeremy Miller

Artichoke thistle flower in Wildcat Canyon Regional Park. Citizens with smartphones can help in a statewide weed-mapping initiative.

If you have a sharp eye for invasive plants – and a smartphone – you can help a Bay Area non-profit in its effort to document the distribution and spread of invasive plants across California.

The Berkeley-based California Invasive Plant Council, or Cal-IPC, has found that weeds cost the state at least $82 million annually in terms of increased erosion and flooding, degraded agricultural land and reduced water supplies.

California is hardly alone. A 2005 study by researchers from Cornell University put the nationwide cost of battling invasive weeds at a staggering $120 billion [PDF].

Climate change is making the issue even more complex, says Doug Johnson, Cal-IPC’s executive director, who is trying to better understand how non-native plants may respond and how they may gain advantage over native plants during prolonged bouts of warming or cooling. Continue reading