On Tuesday, my second day with the Mother Lode field office in El Dorado Hills, CA, I was very excited to head to the field for the first time. Our first stop at a small plot known as “vernal pools” was a little anticlimactic. We weren’t surprised to not find any pools – even outside of conservation circles, the four-year drought has been a hot topic, with water restriction measures getting more and more stringent. Without the vernal pools, my mentor Graciela informed me, much of the native flora we might’ve found at this plot was absent.
Our second venture was more exciting. Graciela and I accompanied the staff’s botanist to Cronan Ranch to check out the progress of a grazing project there. The rolling hills in Cronan are currently dominated by invasive non-natives – mostly yellow star-thistle (Centaurea solstitialis) and medusahead (Taeniatherum caput-medusae). The grazing project aims to give natives a chance to get a foothold by allowing sheep to chew down the existing vegetation and reduce the amount of viable seeds produced by invasives.
The 500 sheep had made quite alot of progress when we arrived. The hill they’d been grazing on looked dramatically different from the others – almost everything green had been eaten. Sure enough, most of the star-thistle had been chewed nearly to the ground, in time to keep it from producing seeds in a few weeks. The sheep had done less damage on the medusahead – perhaps because, as our botanist pointed out, the plant is so high in silica during parts of its life cycle. This makes it unpalatable and undigestible to grazers.