The biggest environmental threat in California?

Here’s another environmental threat to keep you up at night:

“Nitrogen deposition and pollution is [a] more acute threat than climate change. … [But] few people are paying attention.” — Dr. Stuart Weiss, Chief Scientist of Creekside Science.

Weiss’s key paper on Bay Area nitrogen deposition, written while he was at Stanford, has a great title: Cars, Cows, and Checkerspot Butterflies: Nitrogen Deposition and Management of Nutrient-Poor Grasslands for a Threatened Species (Conservation Biology, v. 13 no. 6, Dec. 1999, pp. 1476–1486).

I’m listening to Weiss talk to the California Naturalist class I’m taking right now. Weiss makes some interesting points: Smog does an amazing amount of damage, not only to human lungs but also to non-human organisms. Non-native grasses are big contributors to the increase in pollen in recent times. Free-range cattle on California grasslands can keep non-native invasive grass species under control, providing habitat for endangered species as well as reducing allergens.