New Grazers, New Paradigm
Early last spring, the Sonoma Mountain Ranch Preservation Foundation (SMRPF) entered into a grazing agreement with the Sonoma Mountain Institute (http://sonomamountaininstitute.org/), a local non-profit based on the outskirts of Petaluma at the old Moon Ranch near Vallejo’s fort. For several years now, one of Sonoma Mountain Institute’s (SMI) major projects has been to develop ways to restore soil health and natural vegetation in open rangelands, particularly on the mountain itself. The method they’ve chosen for this restoration closely mimics natural processes under which California’s native vegetation evolved, reproducing ancient grazing effects in a fashion resembling shepherding more than traditional North American cattle-grazing practices.
A Return to the Past
How are SMI’s methods different? Imagine, for a moment, that you are transported back to an era when large herds of grazing animals roamed California’s hills and valleys. These would have been herds of antelope, elk, ground sloths, and mammoths, among others during epochs long passed. These large herds were kept moving as their numbers exhausted the surrounding food supply, individual animals competing for each mouthful of food. Grazing animals were also kept in relatively tight groups by the constant presence of predators like dire wolves (Canis dirus, “fearsome dog”) and saber-toothed cats (Smilodon fatalis—the name says it all!). Across the broad rangelands these grazing groups moved, leaving behind a closely cropped landscape that resembled something machine-mowed. They also deposited a well-distributed source of composting manure, nitrogen, in the form of urine, and nutrients in the form of digested plant materials; all spread across broken-up soil—a perfect, fertile place for seeds to settle in and grow. The land replenished itself in concert with these ancient, grazing herds.
This was the basic environmental rhythm under which our native grasses evolved. Grasses and the other plants that grow among them (such as wildflowers) were cropped down, trampled, and fertilized over an intense period of grazing. Grazing animals ate away or trampled the standing dead material we call thatch. They trimmed back the leaves of the grasses, allowing sunlight to penetrate deep into the plant to stimulate growth. In quick succession, the grazers were forced by a shortage of food and the presence of predators to move off and graze elsewhere. This gave the grasses a long period of time to recover under new and ideal circumstances. Thatch and manure, now mixed into the soil surface, were broken down by soil microbes into fine particulate organic matter that not only nourished growing plants, but held moisture in the soil that the growing plants could use.
Arrival of the Europeans
When Europeans arrived in North America and began to settle the land, in the 18th century, they brought with them the concept of keeping confined herds of grazing animals. Their herds were kept within permanent fencing that never moved, and quickly exhausted their preferred foods. They returned to their favorites over and over, not giving the plants a chance to recover. Favored plants either died off or severely underperformed. Over time, the spaces once occupied by preferred plants are overtaken by other, aggressive, invasive plants—many not palatable to cattle. The result is a shrinking supply of good-quality cattle forage on the range.
SMI is attempting to recreate pre-European conditions, restoring rangeland by confining cattle within temporary paddocks delineated by portable electric fencing. The fence is a surrogate for predators, keeping the cattle tightly bunched. When the paddock forage has been grazed to the desired level—trimmed and thatched, but not over-trampled—the cattle are moved and the fences repositioned. These moves typically occur every 24 hours or so, to simulate natural grazing-and-recovery patterns of the past. By frequently moving cattle, overgrazing is avoided and plants get ample time to rest, recover, and enjoy a period of growth before being grazed again.
Markers of Success
After just one grazing season under the SMI protocol, we’re already seeing significant changes. Portable electric fencing makes excluding cattle from areas relatively simple. Cattle no longer loiter on our dirt roads or in our wet meadows, so roads are in better shape and meadows are less sloppy and torn up. There is less need for permanent internal fencing. Less fencing translates to fewer maintenance costs and a nicer view scape. Since cattle are moved almost daily, their water source has to move with them. This reduces trailing; those deep furrows that result from cattle going back and forth to stationary water supplies. Those deep trails are beginning to disappear.
We are thrilled with the results so far and have every reason to believe that this system of cattle grazing, by reproducing the ancient herd-and-grassland relationship, will restore and benefit our rangelands indefinitely.