I recently participated in a field walk across riparian, meadow and rangeland habitats in the Halleck Creek Valley, led by Wendell Gilgert and Geoffrey Geupel of Point Blue Conservation Science and focused on understanding landscapes through birds. I had not expected to also learn about the impacts of human habitation on landscapes, but I ended the walk with a greater appreciation of the interrelationships between human activities and the lands in which they play out.
The morning started with a neighborly welcome of homemade scones and hot beverages that made our breath in the early morning air meld into the morning mist. But where were our leaders? Cell phone outreach was tried, but only brought us back to quiet and waiting. The reason for the delay fit right in with the theme of the day: a milk truck navigating the ribbons of road threading through traffic and country calm had delayed our hosts.
Wendell, Point Blue’s working landscapes program director, brought his extensive education, experience and contagious passion for healthy land to each step. Geoffrey, the group’s emerging programs and partnerships director, kept our ears tuned to the sounds around us. He supplied each walker with two laminated cards appropriate to the day and the locale, to reference as we progressed. One card focused on 13 birds found in riparian habitats, the other on nine birds found in mountain meadows.
I wished there were a “Healthy Earth Makes Healthy People” degree program, with Wendell and Geoff designing the continuing education units. We hardly took a step before Wendell would point out something right below our feet. This green, long-stemmed clump of grass, he explained, was particularly photo-dependent. On top, it serves as a good grazing plant; under the soil, its long root system helps sequester carbon and increase the soil’s health and ability to retain water. It does well when grazing is balanced; over-grazing can invite less hardy, and less helpful, annual grasses to take root. These aspects of healthy land management are currently being researched here in Nicasio.
Several times during the morning, Wendell referred to the gift of 20/20 hindsight. He was not being trite, but making the point that it is possible for tomorrow’s knowledge to rewrite today’s wisdom. We started out along Old Rancheria Road until we came to a bridge crossing Halleck Creek to the old Rogers Ranch. Here Wendell invited us to look carefully at the differences right and left: downstream had more shade and the roots were unnaturally exposed, whereas upstream was wider and more open, the streambed covered with rocks and organic debris of sufficient complexity and density to completely block one of three culverts under the bridge. (Initially bridges like this one were built with the goal of simply getting across the waterway.) The reason for this disruption to the natural movement of water, Wendell said, was the inadequate size of the culverts, which backed up the flow in one direction while intensifying it in the other.
We walked on, engaging the curious and endearing bovine faces. If the shine of a coat shouts of health, these cows were very healthy indeed. Cows, however, have their own effect on the landscape. They like to relax and ruminate in the shade while limiting the ability of native plants and bushes to grow. Then they leave their distinctive pies behind. Together with the pies, the shade of the trees and the moisture underneath make a perfect bare-ground habitat for nitrogen-hungry thistle seeds to germinate. There they were growing huddled together like someone had just scattered bushels of dark chocolate morsels, crowding out perennials like pine bluegrass and California melic grass, clovers and annual grasses.
Several yards later we were again called to look closely, this time at distant hills. Cows like to trace and retrace their steps, and in so doing create little ridges in the hillsides. This disturbs the flow and absorption of rainwater, which then creates bulges in the hills that, with time, can lead to blowouts. We walked on until we got to a deep gully carved by unnaturally fast-flowing water; changes in the land upstream had allowed forceful water to cut through layers of sediment laid down over many centuries. Now the water, through a complex chemical interaction, was carrying sediment and compounds detrimental to downstream life forms.
Our guides then asked us to focus on sounds. You can assess the health of a riparian habitat by the absence or presence of song sparrows, Geoff said. “Listen. Hear the female wrentit?” he asked. We did. As he explained how rare it was to see a male, he quickly turned and, with great excitement, said, “There, there’s one over there.” (It turned out to be an app from Wendell’s phone.)
The American robin and its love of juniper berries are important to the propagation of juniper. The presence of scrub such as coyote bush, often burned as a nuisance, is vital for the scrub jay. The early blooms of the California buckeye, toxic to non-native bees, are an important food source for native bees, giving them an early start on their pollinating activities.
As we came to the end of our walk, warmed by the good nature and laughter that had enveloped the morning, I knew I would now experience riparian and meadow lands with a deeper sensitivity.
Grace Rogers, a retired psychologist, lives in Nicasio, where she has been active in local affairs since the 1970s.