Archive for April, 2014

Most of us know Yerba Buena Island (aka YBI), if we know it at all, is from tunnel we drive through to get from one end of the Bay Bridge to the other. We may have even gone to Treasure Island, but Yerba Buena is a bit of a forbidding mystery — it’s current owners do not encourage visitors. Ruth Gravanis joined us April 17th, 2014 to uncover some of that mystery.

Two thirds of the island is still mostly owned by the Navy — although not for long, the intent is for them to hand the island over to the city. The other third is owned by the Coast Guard whose station will remain after the Navy is done for good.  Soon this island, will be a proper part of the city, and connected to the easy bay by a pedestrian & bike bridge, with new development slated for both it and treasure island. There is much to know and discover about this place.

~10,000 years ago, it wasn’t an island at all, but a hill in the broad valley that was soon to be the bay. The story of who lived there before the Spanish is still uncertain, but the Island seems to have been used by two different people’s of differing statures and burial practices. The island was used as a fishing camp and a place for gathering acorns. An extensive archeological survey was done, but details have been kept private.

The first westerner to name the island was Juan de Ayala in 1775, who called it La Isla de los Alcatraces (Island of the Pelicans — there is some controversy as to whether he called it this, or the map was transcribed correctly). For whatever reason, it was an English Captain, Frederick Beechy, who called named Alcatraz Alcatraz. He named Yerba Buena after the herb that grew all over the island at the time (the plant no longer grows there naturally).

The name didn’t entirely stick, it has been referred to as Sea Bird Island, Wood Island, and Goat Island. When the island became an official part of San Francisco in 1850, Goat Island was the official name. Goats had been exiled to island after they wrought havoc on the mainland. It was the petition by the Native Daughters of the the Golden West that brought the name Yerba Buena back to the island.

The Island was quarried in the 1860s and the stone was used extensively in Oakland and San Francisco buildings. The Army had a base on the island in the 1860s-1880s as well, but nothing remains on the island of this period. However, two buildings were moved to Angel Island. A lighthouse was built in 1875. Many of the trees seen on the island today are a result of an Arbor Day in 1887 where schoolchildren were brought by ferry to plant trees… a project of Sutro, General Vallejo, and Joachin Miller.

The Army handed over their base to the Navy in 1898 and officers mansions began to be built. Admiral Nimtz was the one of the last Naval officers in residents.  Aside from the mansions, the bridge, and treasure island, all sorts of things got built: administrative buildings, a 1 room schoolhouse, a mine factory, a tower for tracking ship movements.1973 the Coast Guard took up their third of the island. The Navy ceased operations on the island in 1997.

But the cultural/historical side of the island is no the only thing — it has a rich natural history as well. A rare plant study commissioned by the Navy found significant remnants of the original habitats, oak woodlands, dune habitat, tide pools, riparian scrub. A rich mix of native plants, insects, fungus, marine mammals, and birds.

There are many threats to these pockets, invasives like ice plant, eucalyptus (thanks to the Arbor Day in 1887). Eucalyptus isn’t completely without merit, it does provide roosting sites for falcons, and potential for bats, but they need light and space around them to let other things in (here in the Bay Area, not in Australia, very little grows under eucalyptus except invasive ivies).

The next question of course, is when the bike path comes in, and when the Navy has handed over the Island, what comes next. It is likely to become more of a recreation destination, more people will be living on it, and on treasure island, and we have to make sure we do not love it to death. A habitat and sustainability plan is already part of the development agreement, but there are still many things that have yet to be decided — how and where the bike path comes in being a big one.

You can follow the ongoing project at http://sftreasureisland.org

To learn more about the natural side of the island, check out this video from ShengChun Li, and the Treasure Island Museum


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Life in a Cubic Foot

David Liittschwager’s idea of one cubic foot partly started with the idea of having a manageable sample size (the talk was given March 20th, 2014). It is not an uncommon practice to find a limit around observations. So looking at a one cubic foot volume for visible species collecting at different times to find representatives of one day’s time. The size also reflects a common collecting practice of using 5 gallon buckets for collecting, and it is a similar volume.

But in has not turned out to be very limiting. The “dirty secret” for David is that he’s never really finished cataloging within those limitations. The biodiversity that can be found is amazing if we take the time to look. Even a pile of leaf litter in new york city turned up 100 species.

The spots to which he went were chosen by the likes of E.O. Wilson for the biodiversity they know is present. And the most spectacular of these locations have been tropical reefs. He flipped through amazing photo after photo of creatures collected from this little space and carefully sorted out to be identified and photographed.

All those creatures aren’t there all the time of course, but things move and water flows over the reef and through the open skeleton of one cubic foot. Collecting at different times of day and night then going through the process of sorting and identifying and photographing. It took about a month to come up with a representative sample of 24 hours. 

David looked up with some chagrin at a leafy acquatic plant, and said they should have spent time looking through the leaves, they would have found a ton more.

More recently he was out just at the mouth of the San Francisco Bay 100 yards west of the GGB, 100 yards south of the north tower, seeing what pass through a cubic foot of water as the tide moved in out, pulling in with a 300 micron net: mites, water fleas, tons of cephalopods, algae, crab and fish larvae, skeleton shrimp. With an 80 micron net they pulled in the glistening forms of diatoms. On a back of the napkin calculation, in a normal 24 hour period of spring tide, nearly a quarter million linear feet of water would pass through that cube — and maybe  2.6 billion creatures would flow through that space. 

David’s work in these small spaces shows us a different magnitude of beauty and grandeur, life, diversity, and abundance at scale we would not expect. Another lesson in all that we do not know about the planet we inhabit.

Find out more about David Liittschwager’s work at liittschwager.com.

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It’s not actually a lake! All the squirrels are imports! And yes, there are sharks that patrol the waters of this beloved urban slough.

We’ll go on a whirlwind tour of all five Linnaean kingdoms and learn how some of the animals, plants, fungi, protists, and monera fit together in this misnamed watery ecosystem.

Though you’ve walked around its three mile circumference many times, there’s so much more to learn about the process and results of renewed human research at Lake Merritt. Check out recent bio-blitz compilations and other citizen and scientist cooperative research.

Presented by environmental educator Constance Taylor, founder of Wild Oakland.

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