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Treebeard's Stumper Answer
22 March 2002

Roadside Attractions

It's officially spring! It's time to get outside and enjoy the wildflowers that are starting to appear. The best wildflower fields are in the back country on Figueroa Mountain and beyond, far from human disturbance. But it's convenient that many wildflowers are abundant right along the roads. Introduced weeds are common, but there are also many natives like poppies and lupines that thrive along our highways despite traffic and mowing and scraping. Wildlife follows. What environmental factors make the roadsides attractive for wildflowers and wildlife?

Arroyo Lupine (Lupinus succulentus) is a California native wildflower that is often abundant along local roads and highways, like this colony along rural Happy Canyon Road in the Santa Ynez Valley behind Santa Barbara. I shouldn't overstate my claim. Introduced weeds dominate along many roads and highways, but some natives hold their own. Introduced or native, these plants do well along our roads. And it's not just plants that favor roadsides. I regularly see once-endangered White-tailed Kites and other raptors as I drive to and from school. What environmental factors make the roadsides different for weeds, wildflowers, and wildlife?

Our roadsides are a disturbed habitat that is attractive for weeds and some native wildflowers that are adapted to follow fire and flood. Roads collect rainwater and let the sunlight in, like a jungle river. Road cuts create seeps and rocky exposures that some native plants prefer. Caltrans tends our scenic roads, and the cattle are on the other side of the fence. Roads are also avenues for invasive weeds that can take over the wildlands. It's nice to see lupines and poppies along the highway, but you'll find a lot more natural diversity in a remote place like Figueroa Mountain. Take a drive, but then go for a hike!


Roadsides are no doubt the most visible habitat for daily commuters like me, but Roadside Ecology is a still a complicated topic. It's important not to over-simplify. Here are a few of the environmental factors that make roadsides different. The effects are both positive and negative, with the kind of complexity that makes this an interesting subject.

I'm sure there are many more environmental effects of roads, but that's a good start. Here are some links for further research:

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