Biology Reference
In-Depth Information
joint venture, between 1996 and 2010 the region acquired more than
39,000 acres of bay habitats, restored nearly 10,000, and enhanced close to
5,500 (seasonal wetlands got a 5,000-acre boost on these three fronts). An-
other 13,390 acres of bay habitats were in the throes of final restoration
permitting or construction as of this writing. Because it will take years for
many projects to evolve into mature marshes, experts differ as to how
close the region is to meeting its 100,000-acre goal for tidal marsh. But
progress in the tens of thousands of acres is tangible.
“Twenty-five years ago, when I was working for the Audubon Society,
we were just battling one development project after another that impacted
bay wetlands,” says Beth Huning, coordinator of the San Francisco Bay
Joint Venture. “Now, instead of focusing on stopping things, we're re-
creating ecological functions, re-establishing natural hydrology, and re-
connecting habitats and open spaces around the bay. Momentum is on our
side. Landowners are contacting us now, instead of developers. They want
to work with us to protect their lands, rather than build on them.”
Building a wetland from scratch requires more than just taking a piece of
land and adding water. Over time, techniques have ranged from “guerrilla
restoration”—knocking over a weir or blasting a hole in a levee—to the
careful engineering of new landscapes, with detailed attention to the
planting of vegetation, the creation of upland refuges for wildlife during
high tides, and the digging of sinuous channels that mimic their natural
counterparts. Every site presents unique characteristics. For engineers
trained to create stability, the challenge is to design for complexity, vari-
ability, resilience, and long-term change.
According to Phil Williams, “We've gone through successive genera-
tions of restoration projects, where we can actually see how well they did.
We are learning from our experiences by going back, monitoring, assess-
ing, being accountable for the work we've done. It's a learning curve un-
precedented in any other major estuary.”
Through generations of projects around the bay, wetland planners
learned a number of key lessons about what makes a good wetland recipe.
First was that it didn't have to be green to be good, at least not at the start.
Designers of large projects soon stopped planting plugs of cordgrass and
other marsh species in favor of letting tides import seeds.
The second lesson was that in order to foster the natural growth of a
vegetated marsh, the base elevation of the site must be exactly right. Engi-
neers experimented with adding mud until elevations were just above and
