Grown In Marin 

From Marin Agricultural Land Trust News, Spring 2006

Over on the other side of the fence, not only is the grass greener, but thousands of wildflowers display a spectacular spring bloom. What's that other guy got that you lack? It may be a few cows.

When you see cattle or other hungry herbivores standing in the grass, they aren't just posing for photographs, they are usually eating. And when they eat, they eat a lot: full-grown sheep and cattle typically consume their weight in forage in only a month—that's 200 pounds for a sheep and 1,000 pounds for most cows. All this chowing down has a significant impact on the ecology of the grassland.

First, consider what happens when any animal eats. No matter what you choose to call it, animal waste, full of concentrated nitrogen and other plant nutrients, is redistributed to the soil as the animals move about, contributing chemical variation to the environment. Wildflowers often need more nitrogen than grasses (just like the flowers in your garden), so they thrive when herbivores form a major part of the nitrogen cycle.

However, no matter how good the soil, growing plants in the dark is next to impossible; sun and shade are very important factors in shaping their success. When annual grasslands don't support significant populations of herbivores or have intermittent fires, unchecked growth can result in the accumulation of thatch, the blanket of dead stalks and plant remains from previous years' growth that shades seeds and young plants.

Since many wildflowers require strong early season sunlight to activate growth, this "thatch roof" drastically affects the vegetative composition of the grassland. Many scientific studies, including classic comparisons conducted on the Jepson Prairie Preserve in the Sacramento Valley, have documented that when regular grazing is stopped on California annual grasslands, areas once known for their impressive wildflower displays exhibit a marked decline in diversity within a few short years.

Grazers, do, of course, have impacts on the land apart from the removal of grasses. However, one common concern, that freely grazing livestock will eat all those beautiful wildflowers, is simply a misconception. Not only are cattle known to prefer grasses to most flower species, but many of the wildflowers most famous for their stunning displays also manufacture chemical defenses that make their foliage and flowers distasteful to browsing animals. For example, the Douglas iris (Iris douglasiana), common on the rolling hills across West Marin, is partially protected from herbivory by its mild poisons. California golden poppies (Eschscholzia californica), visible as vast blankets of gold on the hillsides of many ranches, also have a mild toxin in their foliage.

Other common species that you are likely to find in grasslands and throughout Marin county are blue-eyed grass (Sisyrinchium bellum), baby blue eyes (Nemophila menziesii var. menziesii), and California buttercups (Ranunculus californicus). Common shrubs, blooming a bit later and closer to eye level, include the buttery yellow bush lupine (Lupinus arboreus) and my personal favorite, the bright orange sticky monkey flower (Mimulus aurantiacus). There are many more wildflowers to find right in our backyards, from the familiar favorites to ephemeral and rare species.

If you'd like to explore local wildflowers further, a particularly good environment for seasonal viewing is the coastal scrub, a characteristic vegetative community which can be found on many of the ranches bordering Tomales Bay, and is accessible to the public at Point Reyes National Seashore. The Abbotts Lagoon and Chimney Rock trails are perennial favorites, or, sign up for malt's Hikes & Tours on the Cerini Ranch or the Gale Ranch to see Marin County wildflowers at their best (see pages 5 & 6 for details). And as you stop to smell the flowers this spring, remember that hungry herbivores play an important role in this— and every year's—impressive displays.

—Stella Cousins