The season is turning here in northern California. Although the hills are still colorful and fragrant with spring wildflowers, when I glance below the level of the blooms, I see that the meadow is drying out, from the ground up. In a few more weeks, the green grasses will become golden…and we will start to scrutinize the neighborhood flora for the first evidence of our local invasive species, yellow star thistle. Star thistle is an affliction that has taken over this landscape while I watched. In 1971, when I moved to this land, there were no spiny yellow flowers in the summer meadows. Although the plant (native to southern Europe) first appeared in California during the 1800s, it wasn’t until the mid-1980s that we realized we had a problem here. Yellow star thistle grows fast, crowds out other species, and can quickly form nearly impenetrable thickets. Deep taproots deplete soil moisture reserves (a real problem in drought-prone California). It is estimated that star thistle now affects fifteen million acres in this state. Around the world, invasive species are recognized as a major cause of the alarming decline in biodiversity. Understanding and solving the ecological problems created by invasives is one of many areas where ecological theory and restoration ecology often cross-fertilize for mutual benefit. For example, restorationists need ecological theory—population models, succession theory, life-history traits—to design effective strategies for restoring landscapes altered by invasive species. Restoration projects, in turn, can provide a valuable laboratory for ecologists studying disturbance theory. Foundations of Restoration Ecology, one of the foundation volumes in our SER series, explores this powerful integration of ecological theory and practice in many different contexts. For a sample of this seminal book, along with fourteen others in the SER series, you can download the free SER Restoration Reader here. Back on this land that I love, the restoration part of our effort to rid the land of yellow star thistle is still in the experimental stage (see the native plant post last week). But after more than a decade of labor-intensive effort, we are doing pretty well keeping the star thistle in check, with a strategic combination of hand-pulling, weed-whacking, and mowing. So, we are armed and ready to do battle when this summer’s volunteers show their sprouts. Bring them on!