Stitching together green corridors
”
Why is there a songbird on the front page of the Chronicle?
”
one of our daughters asked Monday.
The Chronicle that day led the news with an account by Glenn
Martin of the sweeping changes wrought by some pretty modest shifts
in land use in the Sacramento Valley.
Stitching together green corridors
“Why is there a songbird on the front page of the Chronicle?” one of our daughters asked Monday.
The Chronicle that day led the news with an account by Glenn Martin of the sweeping changes wrought by some pretty modest shifts in land use in the Sacramento Valley.
Much of the lower Sacramento River was until recently hemmed in by miles of rockwork and levees. As opportunities present themselves, the river is being transformed, and strips of forest are returning to the river’s edge. As the forests resprout, so does a vast and varied network of wildlife.
For the truly bird-besotted, it’s to be expected that the Chron got a few details wrong. First, the bird capturing the attention of readers across Northern California was not a Golden-crowned Sparrow, as the photo caption indicated, but rather a first-year White-crowned Sparrow. The white stripes will not show up until next year. An informational graphic indicated Brown-headed Cowbirds were introduced to the area, when in fact they simply followed the spread of livestock west to the Pacific.
But (except for dedicated bird nerds) those are inconsequential. The most read paper in the northern part of the state saw fit to trumpet something of great significance.
It’s this: patches of habitat are good, but corridors of habitat are better.
The Sacramento and San Joaquin Valleys once contained vast forests along their rivers. As the rivers flooded almost every spring, they would rearrange sediments, and vegetation followed suit. Towering trees formed a canopy above layers of other plantlife.
The first Europeans to visit the state called these broad riparian forests “green hells,” for the difficult passage they required. Under the canopy, the air was thick with moisture and hot. Insects swarmed. Dense growth made it difficult to see more than a few feet, and even more difficult to navigate.
So it’s only natural that as agriculture came to dominate the landscape of California’s Great Valley, farmers sought to reduce the unproductive acreage devoted to that green hell and to convert it to productive farmland. Moreover, the forests had captured and held some of the valley’s richest soils.
But that, combined with a host of other activities, increased the destruction of flooding, and levees were built and maintained at great expense.
By pushing levees back and restoring at least some of the forests along California’s great rivers, we all gain several important things. First, flood capacity is reduced, and the power of floodwaters is blunted by the vegetation along river edges. Second, corridors of natural vegetation are returned.
Those corridors form highways for wildlife in ways that isolated patches of parks never can. Mountain lions are again appearing on the valley floor. Migratory bird numbers are actually increasing in many cases.
A couple of years ago, when our family visited the Pacific coast of Costa Rica, we stayed in a small community set back from the sea. The government required a 100-meter strip of undisturbed jungle between the beach and buildings. As a result, howler monkeys barked and called each morning. They’re so arboreal that they won’t live where canopies have been disturbed.
Something had transpired to allow one builder to erect condominiums at the edge of the sand, and the jungle was interrupted. Fortunately for the monkeys and other wildlife, there was still enough tangled growth to sustain them. But give it enough time and enough condos and the monkeys are gone.
Corridors allow secretive animals to travel in search of mates and food. They allow young to safely disperse.
That awareness is growing, and it’s becoming an important part of The Nature Conservancy’s strategy. The organization has acquired easements connecting Henry Coe Park’s vastness to the south, and managers are seeking ultimately to create a corridor that runs the length of the Pajaro drainage.
As a green highway comes together, we all win, with healthier landscapes, a more sensible approach to flood control, and new opportunities to hike, hunt or fish.
The animals win, but we may win more.
