Losing the life aquatic
Sacramento’s vernal pools have flourished for thousands of years. Now, threatened by county mismanagement and development, they’re threatened with extinction.
Flat and brown and kind of scorched. That’s one way of seeing the landscape around Sacramento.
But for famed naturalist and writer John Muir, the Central Valley in 1868 was “one sweet bee-garden throughout its length.” Where we see grasslands now, the landscape might have been better described as “flowerlands,” and he wrote that walking across the valley was like “wading through liquid gold.”
“The Great Central Plain of California, during the months of March, April, and May, was one smooth, continuous bed of honey-bloom, so marvelously rich that, in walking from one end of it to the other, a distance of more than 400 miles, your foot would press about a hundred flowers at every step.”
But even in Muir’s time, that landscape was disappearing fast. He observed that “of late years plows and sheep have made sad havoc in these glorious pastures, destroying tens of thousands of the flowery acres like a fire.”
There is, however, a little bit of Muir’s landscape left, bursting with color and life, if you know where to look, and when. Vernal pools are some of the last best pieces of it that still exist. For now.
These unique ecosystems have survived for hundreds of thousands of years, although the landscape around them has been radically transformed. In fact, 90 percent of the Central Valley’s unique vernal pools have been plowed under or paved over. Mismanagement and development endanger what remain.
“This special place is deteriorating,” says Eva Butler, a local champion for vernal pools. “If this continues much longer, these resources aren’t going to be here.”Living laboratories, windows to the past
Here and there, people like Butler are trying to save what’s left of the Valley’s vernal-pool landscape.
Butler is founder of Sacramento Splash, an environmental-education program based at the old Mather Air Force Base. Most weekdays from February through April, groups of students gather at Splash’s headquarters on Excelsior Road.
They trundle out to the field, under the expert tutelage of Butler or one of the other guides, to peer into the pools, catalog flowers and count critters. These small bodies of water are uniquely compact outdoor laboratories, ranging in size from puddles to small lakes. What they all have in common is that they are ephemeral—wet in the winter, dry in the summer.
“Each is an intact ecosystem. It’s just the right scale,” says Butler.
SN&R first interviewed Butler about the Mather pools more than a decade ago, in 2001. She’s since handed the reins of the Splash organization to her daughter Emily, and now splits her time between Sacramento and Maine, where she lives with her husband. But her enthusiasm for Mather, its natural beauty and its educational value is undiminished.
“There are so few places for most kids to study science in the outdoors and experience nature firsthand,” she explains. And she’s convinced that if fifth graders learn to appreciate special places like this, they will continue to value them and work to protect them as adults.
After Mather Air Force Base was closed in 1993, this stretch of the base—about 1,300 acres south of the Mather airfield and out to Zinfandel Road—was designated as a vernal-pool preserve. Unfortunately, the county still doesn’t have an approved management plan or the money to protect the Mather pools. More on that in a bit.
When SN&R visited Mather a few weeks ago, amphibians were abundant in and around the pools. Throughout the season, you can find Western toads and Pacific chorus frogs and the occasional salamander here. By summer, the pools will be dry and inhospitable to such wet-skinned creatures.
Ducks and geese like to snack in the bigger pools. Little mouselike creatures called voles have worn crisscrossed pathways into the grass between pools, as they try to avoid the hungry hawks, kestrels and other birds of prey that cruise the skies above.
Here and there, orange-ish mounds of soil signal the presence of pocket gophers. Butler waves some students over and explains that even something as unassuming as a gopher mound will become part of the show in a few weeks.
“These gopher tufts will create a little microhabitat. Then, later, you’ll see this field of goldfields, punctuated by a tuft of pink monkey flowers,” she enthuses.
The life cycle of a vernal pool is boom and bust. In the summer, the pools are dry and drab. In the winter rainy season, they flood; the underlying hardpan keeps the water from draining away.
The aquatic phase begins, seemingly cold and dead. But late in January and into February, the pools transform again. Vernal-pool buttercups begin to sprout along the bottom of the pool. Soon, the water teems with crustaceans like tadpole shrimp and fairy shrimp, and others specially evolved for this habitat, which have lain dormant in the baked mud all summer, waiting for the rainy season to release them.
Splash has special permits from the U.S. Fish and Wildlife Service to scoop some water out of the pools, so the students can do a proper inventory: copepods, flatworms, frog tadpoles, crab shrimp—the list goes on, Butler explains. “Half of the things you find in vernal pools are found only in vernal pools.”
In fact, some of these special crustaceans were on the planet even before the first fish. Accordingly, today they are only found in spots where fish cannot live—like the salty waters of Mono Lake, or in vernal pools which are otherwise dry most of the year.
As the weather warms and the rains subside, the water begins to evaporate. By early April, many of them are dry and boasting bright rings of flowers—the blue downingia, tiny popcorn flowers with their white petals and yellow centers no bigger than a letter on a printed page, and blue lupins. In between pools are great stretches of frying-pan poppies, smaller and yellower than their more famous cousin, the California poppy.
Some of these flowers, like the meadowfoam, downingia and another vernal-pool native called goldfields, each have their own specialist bee species, which collect pollen only from that particular vernal-pool flower to feed to their offspring. These pairings are the product of millions of years of co-evolution. One sweet bee garden, indeed. There are different theories about why these flowers grow in rings. Some scientists think that some species are genetically suited to sprout at certain depths of water. Plant ecologist John Gerlach speculates that it may have more to do with the ducks, who dabble in the bottom of the pools and churn up the seeds and sprouts, which then ripple out to the banks and form flower rings later on.
Whatever explains the striking pattern, the flowers only last a few weeks. Eventually, the moisture and the green will be gone, and these pools will return to the brown and burnt landscape of summer.
The gently undulating hills here were all created by the coming and going of water. The pools and swales are the result of great alluvial fans of sediment and rock that were pushed around by an ancient and now-departed river. As this ancestral American River flowed and changed its course, it carved three distinct terraces into the land. The upper is the oldest terrace, formed perhaps 250,000 years ago. The “youngest” part of the landscape, down by the Mather airport runway, is a mere 50,000 years old.
Gerlach, who visited the vernal-pool areas at Mather with SN&R in March, says that 50,000 years ago, grizzly bears and elk roamed the area. There was no grass then; that only came when farming and cattle were introduced. Gerlach points out what at first looks like some tall grass, a little higher than the rest of the plants around. The shoots are round and smooth and leathery. These are a native species, a kind of lily.
“Where we’re standing right now, there would be grizzly bears just ripping through here and eating the bulbs of these lilies. Bears are like big pigs.” Native Americans would collect the lilies, too, using digging sticks, and then roast them.
Then came the plows and the sheep and the cows. Irrigation ditches changed the hydrology of the valley, flower lands were converted to grasslands. At low elevation near the river, where the soil is most fertile, vernal pools were wiped out.
“The low ones are mostly all gone, due to rice farming and building,” says Gerlach.
On higher ground, where the soil wasn’t fertile enough to farm, grazing cattle tromped and smeared the features of the landscape. The taming and draining of the Central Valley and the great grass invasion “was the biggest conversion of habitat on the planet,” says Gerlach.
The conversion is still happening. New invasive species are cropping up. Gerlach spots some waxy manna grass, which looks just like a weedy grass that might pop up in your lawn. “This is a vernal pool killer,” he says, pulling out a clump of the noxious stuff.
Elsewhere, the pools are threatened by a weed called medusahead, which looks a bit like tiny brittle fish bones atop a long stalk. The list of nonnative species goes on: Filaree, hawkbit and Italian thistle are all moving in.
And in the last few years, they’ve begun to threaten vernal pools that had been pristine before. Butler thinks it might be because there hasn’t been enough rain. “Last year was the worst year I’ve ever seen.”Saving the best and last
Butler says the change in the last decade has been dramatic. “There [were] once magnificent pools that [had] been here for 100,000 or 200,000 years. You can’t even find them anymore. The pace of change has been that fast,” she says.
This area needs active management. Hand-pulling of weeds, some carefully chosen herbicide, some meticulously timed burning, maybe some goats—there are several tools in the toolbox. “We know how to do this stuff,” says Butler.
But there’s been no plan and no money. As part of the conversion of the base, which was closed in 1993, Sacramento County agreed to create a vernal-pool preserve of about 1,200 acres. It’s just one piece of a complex reuse plan for the 5,000-acre base that includes an airport, commercial development and lots of suburban housing.
The preserve exists on paper. But the management plan is still not in place, 20 years later. County economic-development officials say that execution has taken so long, in part, because it’s just one piece of the drawn-out conversion. The last parcel of base property was only officially transferred from the Air Force to the county this year.
The plan is also in some way dependent on the ongoing development of the base, and development everywhere ground to a halt during the recession. Then, add in the time it takes for several bureaucracies to coordinate anything.
“We really took our time and worked closely with the agencies to produce a wetlands-management plan like the region has never seen,” said Clark Whitten, Mather’s program manager for the county’s office of Economic Development and Marketing.
The actual management, whether it be burning, grazing or other methods, will be funded by new residential development around the south part of the base.
The developer will be required to pay fees for the preserve upfront before construction begins. But when that will be is anyone’s guess. “It’s really market driven,” says Whitten.
Butler is hopeful that a plan may finally be coming together—county staff expects to ask the board of supervisors to approve it this summer. “Preserves require constant vigilance and active management,” she says, adding that she believes action to combat the weed invasion “cannot wait another season.”
Elsewhere, a different kind of invasion threatens much of the remaining vernal-pool habitat. “Every development project proposed in Sacramento County sits on top of vernal pools,” says plant biologist Carol Witham, president of the Sacramento Valley chapter of the California Native Plant Society.
Witham ticks off the names of the development projects now in the pipeline with Sacramento County or the city of Rancho Cordova, projects like Cordova Hills, SunCreek, NewBridge. “It’s tens of thousands of acres of new development,” Witham says, adding she’s “seen no evidence” that the massive amounts of development are needed. There’s plenty of developable land closer in to the already-built urban areas and existing infrastructure—if we need it. “And we have a surplus of housing and commercial development. Enough to meet our needs for the next 20 years.”
The Environmental Council of Sacramento is suing the county for approving the controversial Cordova Hills housing development on the east side of Grant Line Road, slamming it as “classic leapfrog development.” It also straddles some of most pristine vernal-pool habitat in the county.
“These are a loci of tremendous diversity. More diverse than the Galaacute;pagos Islands,” says Sean Wirth, a member of the ECOS board. “We’ve modified and modulated everything. The vernal pool is one of the last hydrologies that is still intact.”
The Sacramento County Planning Division estimates that there are about 3,800 acres of vernal pools left in the south and east portions of the county. Environmentalists and county planners are hopeful that the South Sacramento Habitat Conservation Plan, once it’s finally adopted later this year, will help to protect existing pools. It will provide a mechanism through which development fees can help fund restoration and preserves in areas off-limits to development.
In 2010, county planners estimated that a little more than 300 acres of vernal pools in the south and east county would be lost to development, or at least “impacted” by it. That’s about 10 percent of what remains. County officials warn that those numbers are being updated and may change. And they don’t take into account pools that could be lost for other reasons. Agricultural operations, such as plowing and converting open space to vineyards, can also lead to their destruction. And those 300 acres include just “wetted” pools. The health of vernal pools is also dependent on the land around it—the uplands. The numbers are still being finalized, but overall, the plan anticipates that roughly 35,000 acres of grasslands, wetlands (including vernal pools) and open space will be protected by the HCP. But another 35,000 acres will be impacted by development.
“Ironically, whatever management and preservation the county ultimately does will be funded by development of other vernal pools,” says Wirth. A lot of pools will be lost in the process.
“It’s about protecting the right pools, and making sure they are linked to each other,” says Leighann Moffitt, planning director for Sacramento County.
As development moves forward in the east county, Moffitt says the plan is to create connected vernal-pool areas between the new subdivisions. For example, Moffitt says the developer of Cordova Hills is being asked to set aside 400 to 500 acres of vernal pools. These will be connected to vernal-pool preserves at the NewBridge project and at SunCreek. The heart of this extended corridor will be the Mather preserve.
The developers don’t have to participate in the HCP; it’s strictly voluntary. But that would mean having to negotiate separately with the U.S. Fish and Wildlife Service, the state water board and other regulators in order to get development permits.
Developers who go it alone might wind up having to spend more money and protect more acreage—and the county would find it that much harder to coordinate, connect and save the “right pools” and the best habitat.
Meanwhile, “the inventory of vernal pools keeps dwindling,” says Witham. And with it the little bit of the landscape that existed just 100 years ago.
For example, one University of the Pacific graduate student last year submitted a master’s degree thesis identifying 12 previously unidentified species of crustaceans found in pools around the Sacramento region.
“What else might we be losing by paving this over?” asks Witham.
Gerlach says that people may underestimate the importance of Sacramento’s wetlands landscape because it’s not dramatic.
“That area is equivalent to Half Dome in importance, considering the species present, the age and scarcity of this natural resource,” he says.
“We are getting down to the last of the last. The last of the oldest of the vernal pools.”