Freshwater vernal pools alongside busy Highway 4 may seem like an unusual home for an endangered plant. But here a golden, daisy-like wildflower makes a delightful ephemeral display on spring days. JMLT cares for this last-known stand of Contra Costa goldfields within its namesake county. The shocking-yellow flowers grow thickly in meadows, creating sheaths of vibrant color that astound onlookers. The Contra Costa goldfields (Lasthenia conjugens) is an annual in the aster family, and is actually an herb that grows to a height of 4 to 12 inches with light green, feather-like leaves. Only 13 known populations exist in four counties. Although this species once grew throughout a large swath of coastal California and in some inland areas, development nearly brought it to extinction. Non-native grasses have also played a part in the plant’s near-demise, killing nearly all the other goldfields growing in Contra Costa County. The federal government classified the goldfields as endangered in 1997.
In 2002, the Contra Costa Transportation Authority awarded JMLT a conservation easement on a 30-acre preserve east of Hercules. When we took over the property, the number of plants had plummeted to nearly zero. Cattle grazing beat back the deadly grasses and give the goldfields a chance to recover — and it worked! To prosper, the plant needs pools that form in the winter but dry out in the spring. Interestingly, the churn and divots from cattle hooves create these little pools, collecting water allowing the plant can thrive. The goldfields have burgeoned here since, bringing their numbers back into the thousands.
In addition to the seasonal wetlands comprising the Contra Costa Goldfields preserve, JMLT manages nearby vernal pools as well as a section of Rodeo Creek that traverses the area. The creek provides a rich habitat populated with native fish as well as amphibians and frogs, including the California red-legged frog, a federally listed threatened species. Numerous birds including mallards, great egrets and belted kingfishers have been observed foraging along the creek. The area is home to coyotes, raccoons and small rodents. Annual biological assessments track the number of flowers that now thrive on the property.
Spring is best for viewing the gorgeous goldfields in bloom and JMLT leads wildflower hikes during that time of year.
GETTING TO CONTRA COSTA GOLDFIELDS
The Goldfields are located adjacent to Highway 4 near the city of Rodeo. From Eastbound Highway 4: Take the Sycamore Ave exit, turn left onto Claeys Lane, go over the overpass, the Goldfields will be on the right just past the overpass. From Westbound Highway 4: Exit on Claeys Lane, the Contra Costa Goldfields property is on the left.