The California That Was: A Day in the San Luis National Wildlife Refuge

I've spent a good part of the last few months blogging about the "Hawai'i That Was", in which I have been exploring the bits and pieces of the original islands that existed before European/American incursion. I will even finish the series before long, but in the meantime I've been keeping up with the new semester (already a third of the way over), and the fall field trips. I had a break last Saturday and Mrs. Geotripper and I headed south to see if any of the migratory birds had arrived at our local refuges.

Tule Elk at the San Luis NWR

The first refuge, the Bear Creek unit of the San Luis National Wildlife Refuge was sort of a bust, as no water had been allocated to the pools there, but the Tule Elk autotour a little farther south afforded some neat photo opportunities. A huge Tule Elk buck rose out of the grassland, and I was suddenly reminded that there is a "California That Was" as well. I live in a huge prairie, the Great Valley of California, and even though most of it (95%) has been consumed by agricultural and urban development, there are still some pieces left here and there where one can be reminded of what a treasure this valley truly is (or was).

Can you see why I took this picture?

The prairie grasslands extended for four hundred miles from present day Bakersfield to Redding, and the valley averages forty or fifty miles across. Although it receives rainfall equivalent to a desert in the southern portion, rivers draining the Sierra Nevada provided plentiful water, so much so that a large part of the south valley was covered by shallow lakes (Buena Vista and Tulare). Those lakes disappeared during the last two centuries as streams were diverted for agricultural development.

The valley supported a rich ecosystem that included numerous grazing species such as the Tule Elk, deer, and pronghorn antelope, and predators that included wolves, coyotes, mountain lions, and Grizzly Bears. Many of them are gone, but we were privileged to see the Tule Elk herd and a well camouflaged deer that made its way to the Salt Slough for a drink.

Salt Slough in the San Luis NWR

More than anything else, the "California That Was" was bird country. Millions upon millions of migratory geese, cranes, and ducks called the valley home during the winter months when the northlands were covered with ice and snow. The lakes, rivers, and wetlands provided food and shelter for the tired migrants. Although far less land is available to them today, hundreds of thousands of birds still spend the winter here, and that's what we were looking for on Saturday. We heard that some Sandhill Cranes had already arrived and we wanted to have a look.

Egrets and Sandhill Cranes at the Merced NWR

Hundreds of them had indeed arrived, but we were surprised by the number of egrets present in the refuge. It's strange how such birds can be clumsy looking and graceful at the same time.

Great Egret at the Merced NWR

The California prairie is perhaps the most altered landscape on planet Earth. It's nice to know that there are dedicated groups of people working to maintain some small corners of the valley for the birds and other wildlife. It's a real privilege to have a chance to see what was once here.

Sandhill Crane at the Merced NWR

Driving Across the Most Dangerous Plate Boundary in the World: These Rocks are All Wrong!

The view from Muir Beach Overlook, midway between San Francisco and Point Reyes National Seashore

Point Reyes National Seashore: Is it land's end, or ocean's end? From a human point of view, it is the former. This is the far west of North America, and you can't go any farther without a boat or plane. But if we consider the oceanic crust that was being subducted beneath the continent here, it is the latter. It's where the ocean floor came to an end by being consumed and presumably melted within the Earth's mantle, the subcrustal layer that extends to the core some 1,800 miles down. In any case, it is the starting of our journey across the most dangerous plate boundary in the world. As I've pointed out before, it isn't presently the most dangerous boundary; it changed long ago, and the stripping effect of erosion has revealed the inner workings of the subduction zone that produced much of California's present-day landscape.

Drake's Beach, with outcrops of Purisima Formation that reminded early sailors of Dover.

But the rocks at Point Reyes are all wrong! As was mentioned in the first post of this series, an ocean-continent convergent boundary (a subduction zone) consists of three structural features: an accretionary wedge, a forearc basin, and a magmatic arc. The wedge deposits should be found nearest the coastline, and the granitic or volcanic rocks of the magmatic arc would be found far inland. As we look around at our journey's starting point at the lighthouse at Point Reyes, we find rocks related more to the magmatic arc. There are exposures on the Point Reyes peninsula of granitic rock, metamorphic rocks, and the silica rich sediments that have been eroded from them. Why are things out of order here?

It's due to the structural changes that resulted in the cessation of subduction and the beginning of movement on the San Andreas fault. At transform boundaries like the San Andreas, the crust and upper mantle (the lithosphere) are shifting laterally. The rocks west of the fault, Point Reyes, the Central Coast's Salinian Block, Los Angeles, San Diego and the Baja Peninsula are moving as a unit to the northwest, more or less towards Alaska.

Around 30 million years ago the rocks of Point Reyes were in Southern California. Around 29 million years ago a major restructuring of plate boundaries took place. Granites and metamorphic rocks related to the Sierra Nevada were sliced off and started their northward journey and we find them today underlying the lighthouse at Point Reyes. And that's where we now start our journey across the most dangerous plate boundary.

Source: USGS (http://pubs.usgs.gov/of/2005/1127/)

I'm afraid we've got a bit of a walk before we can get in a car and start driving. The lighthouse at Point Reyes is situated midway up the cliff above the sea, and we've got a climb of about 300 steps to reach our road. The rocky headland where the lighthouse is located is composed of granitic rock and some overlying late Cenozoic sedimentary rocks.The rocks are resistant to erosion and stand as a high rocky point.

Photo by Mrs. Geotripper

Take a few deep breaths and start climbing...

The cliffs of granitic rock are steep and nearly vertical. If you listen carefully, you may hear the barking of sea lions in the small coves below. During the right time time of year you may spot some of the migrating whales offshore.

The climb, though, is worth the effort, because when we reach the top of the hill there is a marvelous view to the north towards one of the longest unbroken sandy beaches in central or northern California. One might think it would be a popular swimming beach, but the fierce winds, high and unpredictable waves, and cold water make for uncomfortable conditions.
From this lofty perch we can make out the mountainous terrain of Inverness Ridge, composed mostly of the granite and metamorphic rocks of the Salinian Block. The gentle westward slopes expose sedimentary rocks of Miocene and Pliocene age, deposited during the long journey northwest from Southern California when the rocky basement was submerged beneath the ocean waves. Active dune fields can be found along the extensive beaches of the peninsula.

The peninsula is protected from development as Point Reyes National Seashore, and is a haven for wildlife. On our drive towards the "mainland" we are likely to see numerous bird species, including California Quail. A herd of Tule Elk graze the grasslands along the road.

The road climbs over the crest of Inverness Ridge and descends to the village of Inverness and the shores of Tomales Bay. We've reached the San Andreas fault, the second most dangerous plate boundary in our narrative. Maybe the rocks will be "right" when we find a way to cross the boundary between the Pacific and North American plates.

A Scarred and Beaten Ecosystem Persists: The Native Species of the Great Valley

I live in an extraordinary place! In my last post on the Great Valley I was discussing our use and abuse of our most precious resource, one of the richest soils on the planet. Some 95% of the original ecosystem has been manipulated by humans to achieve the highest biomass production possible. Our burgeoning population has to eat after all, and the amount of arable lands is declining worldwide, not expanding. I also posted a number of photographs that intimated what the Great Valley might have looked like prior to 200 or so years ago when European colonists began twisting the landscape to their desires. The valley must have been a fascinating sight in all seasons!

Cedar Waxwing (Bombycilla cedrorum). For more pictures of these beautiful birds, check out my post at Geotripper's California Birds.

Since arriving home after nearly two weeks of extensive travels, I finally had a chance to get out and check my walking routes, around the pasture near my home, and out by the "mini-wilderness" on the west campus of Modesto Junior College. We also stole a moment from our errands today and watched the sun set at the Beckwith unit of the San Joaquin National Wildlife Refuge, which has a viewing platform just eight miles west of town. There had been a lot of changes in the two weeks as a number of migrant species had arrived, including especially the Cedar Waxwings (above).

Nuttall's Woodpecker (Picoides nuttallii), a California endemic species.

Walking through my normal haunts, I was struck once more with a realization about the scarred and embattled ecosystem I live in. There are survivors of the apocalypse still living among us. Like a war zone, there are vast areas of destruction, and little enclaves where the native species still hang on. Sometimes it is in stretches of woodland along rivers where the ground was too uneven to plow. In other instances, the alien invaders happened to plant ornamental trees that produce just enough berries or fruits that the natives can thrive. In a few precious localities, the alien invaders set aside larger environments from abandoned farmlands (partly so they could hunt the natives species, but that's the Faustian bargain that had to be made). In any case, the walks and observations this week for some reason included no Pigeons, Starlings, or House Sparrows, all of whom are opportunistic alien species. The birds I saw were the native species that had found a way to survive in this new alien world. There was a Nuttall's Woodpecker, a California endemic (when one includes a portion of Baja California, anyway). It was hunting for insects on fenceposts instead of trees.

Yellow-billed Magpie (Pica nuttalli):  More on this California endemic can be seen in this post.

There was a small flock of Yellow-billed Magpies in the pasture. These striking birds are a wholly Californian endemic species, found only in our Great Valley. They were almost wiped out by the West Nile virus, but they are slowly making a comeback.

Western Bluebird (Sialia mexicana)

I see the Western Bluebirds on occasion throughout the winter and spring. I think they migrate up into the Sierra Nevada during the summer. 

Western Scrub Jay (Aphelocoma californica)

The Western Scrub Jay is a perennial visitor to the feeders in my backyard. They've done well in relation to agricultural development, especially with nut trees, as can be seen above. They'll often make noise on our roof as they peck at pecans (and a number have taken root in our yard after pecans being left behind by the jays)

Oak Titmouse (Baeolophus inornatus) on a west campus oak tree.

Another more-or-less California endemic is the Oak Titmouse (Baeolophus inornatus). It ranges a little into Baja California and Oregon. The acre or so of oak trees in the "mini-wilderness" provides them a bit of valley habitat in our area.

Sooty Fox Sparrow (Passerella iliaca unalaschcensis)

Finally, there is a Sooty Fox Sparrow (Passerella iliaca unalaschcensis) that I discovered Tuesday on the west campus of my school. I'm new at this birding business and so was not used to searching the leaf litter for what I always thought were House Sparrows. The Sooty is one of four subspecies of Fox Sparrows. The number and variety of American sparrows is incredible, and is a startling picture of ongoing evolution in action.

It's inspiring to find that some hint or echo of the Great Valley's natural heritage still survives here and there, especially when it is a short walking distance from home or work. More than anywhere else, though, the glory of the ancient days still lives on in the federal bird refuges that line our valley like a string of pearls. Last night we saw a sky filled with migratory birds, thousands of them, who still have a winter home on part of the valley floor (see the video at the top of the post). These are places that should be protected and cherished, and not criticized because they take up some of the water in these hard drought years. Although I understand farmer resentment in such situations, the total water devoted to wildlife survival is no doubt a small percentage of the total utilized, and I'd rather see a healthy population of native birds over an additional field of cabbage or corn.

Where the Sierra Nevada Rises from the Sea: Point Reyes National Seashore

Drake's Beach, with outcrops of Purisima Formation that reminded early sailors of Dover.

Around 30 million years ago major parts of Central California were in Southern California. It's about that "simple". Around 29 million years ago a major restructuring of plate boundaries was taking place along the Pacific Coast. A subduction zone (convergent boundary) that had influenced the California margin for nearly 200 million years, forming the granitic rocks of the Sierra, was changing over to something new. It was transforming, so to speak.

For many millions of years, oceanic crust and exotic terranes were carried eastward towards the continent, only to be forced beneath the edge of North America (subducted). Eventually the source of oceanic crust, the East Pacific spreading center, made contact with the convergent margin and subduction ended. Because of the relative motion of the two plate edges, a new fault system developed, the San Andreas, and a portion of Southern California began to move northwestward along the new fault. Such zones that divide crustal plates from one another are called transform boundaries. Granitic rock that had formed as part of the Sierra Nevada Batholith was sliced off from the south end of the province and was carried north several hundred miles (see below). The displaced granitic rocks are referred to as the Salinian Block.

The Point Reyes Peninsula is one of the more intriguing corners of California. It's connected to the California Coast Ranges after a fashion but it is a world apart. Tomales Bay, Olema Valley, and Bolinas Lagoon mark the location of the San Andreas fault. The epicenter of the infamous 1906 San Francisco Earthquake was close to Point Reyes, and offsets totaled close to 20 feet during the magnitude 7.8 seismic event.

The peninsula is protected from development as Point Reyes National Seashore, and is a haven for wildlife. During my visit several years back I captured my best shot ever of a California Quail. On our way to the beaches, we saw a herd of Tule Elk.

The Peninsula has several distinct geological sections. The mountainous terrain of Inverness Ridge is composed mostly of the granite and metamorphic rocks of the Salinian Block. Much of the western and southern parts expose sedimentary rocks of Miocene and Pliocene age. During the journey northwest from Southern California, the peninsula was submerged beneath the ocean waves. Active dune fields can be found along the extensive beaches of the peninsula.

Drake's Estero is an interesting feature. The branching arms of the bay suggest that it is a submerged river valley. The shallow water has proven to be a good spot for oyster farming, and the 80 year old business is embroiled in a battle with the park service over land-use issues.

Source: USGS (http://pubs.usgs.gov/of/2005/1127/)

From the headland of Point Reyes, Point Reyes beach stretches northward for around 10 miles, making it one of the longest stretches of sandy beach in Central or Northern California. As popular as it might have been, the fierce waves and very cold water make for uncomfortable water play.

The rocky headland where the lighthouse is located is composed of granitic rock and some of the overlying late Cenozoic sedimentary rocks. The lighthouse is visible from as far as 24 miles away, but fog obscures the view for around 140 days a year. Winds are nasty (highest recorded was 133 mph), and the temperature generally hovers between 50 and 60 degrees Fahrenheit all year.

Reaching the lighthouse requires descending 300 steps, but during the rare clear days, the spot is one of the best in California for whale-watching. Expect crowds on the nice days...

Steps leading to the Point Reyes Lighthouse

In the next post, we'll explore the more inland part of Point Reyes National Seashore, mainly Tomales Bay and Bolinas Lagoon.

Point Reyes Lighthouse, constructed in 1870

Traveling in the Way-Back Machine: The Great Valley as it could once again be...

I've written a couple of posts about my "backyard" discovery of the San Luis Wildlife Refuge Complex that preserves 26,000 acres of Great Valley prairie and wetlands environments. In the first, I referenced the "Way Back Machine" that Mr. Peabody the dog and his boy Sherman used to explore the past during the Rocky and Bullwinkle Show (actually the WABAC machine). I used the term in the sense of traveling back in time to the way the Great Valley once was before European settlers co-opted the valley for agricultural development.

The more I've learned about the refuge and what they've been trying to accomplish, I'm beginning to think of the "way-back" as being a return of at least a part of the valley to the conditions that allowed the natural wildlife and vegetation to co-exist with the human community. We are trying to put the rather tattered "web" of life back together.

The Tule Elk was an integral part of the valley ecosystem. They are a subspecies of the Wapiti endemic to California. They were major grazers of the valley floor along with pronghorn antelope and blacktail deer. They were preyed on by wolves and California Grizzly Bears. Before the settlement of the Great Valley by Spanish, the Mexicans, and the Americans, more than 500,000 were thought to exist in California. They made great eating, and good leather. They were already being slaughtered in the early 1800s, but the Gold Rush truly put an end to their existence. In 1873 the state legislature, with ironic timing, banned the hunting of the elk, but they were thought to be already extinct. In 1874 a single breeding pair was discovered on the shores of the now non-existent Buena Vista Lake, and the cattle baron Henry Miller placed them under his protection. He is credited with saving the species.

The elk had a tenuous existence in the years following. Despite building up some numbers, hunting and poaching reduced the population to 21 individuals in 1895. Efforts began to protect the species by establishing herds at several isolated locations, including the Owens Valley east of the Sierra Nevada. One of these herds was successfully started at San Luis in 1974, and is now stable at around 50 individuals living on 760 acres (a bit over a square mile). "Surplus" elk are transferred to other refuges to maintain grazing conditions. The restoration of the elk population has been a success, and there are around 4,000 of them around the state.

An auto tour at San Luis encircles the elk preserve, and we saw 30-35 of them on our drive the other day. Their enclosure is big enough to ensure good grazing conditions and to allow them some degree of privacy (lots of trees and riparian habitat to hide in).

To wrap up our exploration of the refuge, I'm including a few landscape photos to give you a feel for the place. Below is the edge of the elk enclosure and some of the dry grasslands. Not much to look at on this summer day, but you can be sure we'll be back in the spring after a few rainstorms. I expect there will be quite a flower display.

Salt Slough once drained part of the San Joaquin floodplain and hosted salmon runs and excellent wildlife habitat. Agricultural development and disruption of the riparian forest turned it into a muddy agricultural runoff channel contaminated with selenium and other toxins. Part of the efforts of the refuge managers has been to return the slough to a condition resembling its original environment. Fishing is already possible.

There is a viewing platform along Souza Marsh with a telescope. I'm glad I looked before focusing!

The marsh was pretty quiet on this summer day, but I imagine it will come to life in the migration season. We'll be back for sure!