The first month on Cat Ba Island – getting my bearings

My apologies for the long gap between posts, life has been a bit busy.

I recently began a new position in Vietnam, on Cat Ba Island to be specific.  My first impressions are that this is a damp and precipitous landscape.  I have not seen the sun since I arrived in Vietnam on March 4th.  For Cat Ba Island this means a riotous profusion of greenery tempered by the steep terrain and lack of soil.

Where the northern end of the road terminates

Where the northern end of the road terminates

This is a land where Ymir’s bones lie close to the surface, broken and weathered, their calcium leaking back into the waters from which these precipitous cliffs rise.  The geology is the first thing that strikes you here.  The cliffs have been weathered by millions of years of rain, the ever-so-slightly acid rainwater eating into the ancient limestone creating a mature karst landscape.  Like bones, coral, and seashells, limestone is primarily made up of calcium carbonate, which in other forms makes marble and dolomite.  This is probably one of the reasons this is a place where snail diversity is immense, ranging from tiny frilled creatures more akin to limpets to giant land snails, many of which are still unknown to science.  Snails need lots of calcium to make their shells.

Unknown frill terrestrial snail

Unknown frilly terrestrial snail

Land snail shells collected around the office - and a wasp nest

Land snail shells collected around the office – and a wasp nest

The banded limestone found here is a relic of abundant diatom (a type of plankton) skeletons laid down five hundred million yeas ago and subjected to the vagaries of time.  Limestone, while soft to the chisel and hammer, is a remarkably durable stone at the macro-scale, one of the reasons climbers like it, but at a chemical level it is easily weathered.  We are often told that water has a pH of 7, that is it neutral.  Natural rainwater, we then assume, should also have a pH of 7, but it is closer to 5.6 due to the dissolution of carbon dioxide into the water making carbonic acid.  A pH of 5.6 is about as acidic as a cucumber or an onion for comparison.  Of course, other environmental factors can reduce this tremendously, leading to extremely acidic rain.  Rain falling on the limestone erodes small channels in the rock that look like thumbprints in wet clay.

Rainwater erosion on limestone

Rainwater erosion on limestone

Eventually these concentrate water flow, carving small holes in the stone reducing it to a swiss-cheese like structure with an extremely jagged and sharp exposed surface.  These little caves connect into larger caves.  In these protected, damp environments bacteria grow, exuding waste products and creating hydrogen sulfide that mixes with the water and makes a weak sulfuric acid, increasing the chemical weathering.  This cycle persists, eventually leading to enormous caves.

The airflow in these caves evaporates the mineral rich water tricking through the now porous stone and the calcium carbonate re-solidifies into stalagmites, stalactites, soda straws, and any number of strangely beautiful and complex cave structures.

Caves often form in weak portions of the stone and, eventually, gravity takes its toll and the weakened rocks collapse leaving behind steep spires and fields of slowly eroding boulders.

Limestone spi

Limestone spire in the north end of Cat Ba Island

Cat Ba and Ha Long Bay are examples of a drowned karst landscape, a mature karst landscape that has been flooded by rising waters.  What little soil does form is washed down into the many bays, coves, and channels of the region, leaving little for plants to sink roots into.  In the shallow waters of the bays mangroves find nutrients, in abundance.  Here mangroves are near the northern margin of their range, their numbers restricted and the trees short, making low dense forests.

Gray mangroves on the south western side of the island

Gray mangroves (Avicennia marina) on the south western side of the island

As in many places, the mangroves are in trouble here, often cut down to make shrimp farms.  This leads to reduction in local fisheries, increased erosion, and lack of protection from storm surges and tsunamis.  The local government is taking steps to protect what remains and to, potentially, restore some of the previous mangrove forests.  In the rich mud of the mangrove regions there are numerous animals, among them one of my favorites, mudskippers, amphibious fish that hop about in the mud protecting their little territories.

Mudskipper amongst mangrove roots

Mudskipper amongst mangrove roots

On the cliffs however there are few nutrients and plants grow in what cracks and declivities they can find.  As per many islands there are a number of endemic species, here one of the most commonly seen ones is the Ha Long Cycad (Cycas tropophylla), an ancient type of gymnosperm that looks like a cross between a fern and a palm tree.

Ha Long Cycad (Cycas tropophylla), endemic to a 400km square area, globally rare, locally abundant

Ha Long Cycad (Cycas tropophylla), endemic to a 400 square km area, globally rare, locally abundant

The season here is shifting into spring and some of the trees have begun blooming, among them the hoa gạo or Cotton Tree (Bombax ceiba), so named for the kapok-like fibers that are found in the seed pod.

Hoa Gạo (Bombax ceiba), Cotton Tree in English.  The Vietnamese name translates to "Rice Flower"

Hoa Gạo (Bombax ceiba), Cotton Tree in English. The Vietnamese name translates to “Rice Flower”


I still have not seen the little primates I came here to work with, they are few in number and they clamber about on the vertical cliffs like, well, monkeys.

Soon though.

A New Job, a New Voyage, An Endangered Species

The rain has finally come to California, bringing with it the promise of new growth and greenery.  As it rains outside the window I am inside,  surrounded by loosely organized piles of clothes, books, outdoor gear, and laptop peripherals attempting to fit my life into two 20kg bags.  Before I go I need to take care of all those technological tasks our life is filled with as well, back up my computers, transfer my iPhone and iPad to a different computer (Apple, you really need to make that easier to do), and do the final run-through on what I am taking with me.  Despite all this, my mind is only partially on the task at hand.

Several weeks ago I was offered a position working on primate conservation in northern Vietnam and my mind is on the location, the people I will be working with, and the upcoming tasks.

The Gulf of Tonkin - NASA image

Northern Vietnam, Southern China, and the Gulf of Tonkin – NASA image

This is exciting, not in the least because Vietnam, like much of South East Asia, (and Southern China) lies firmly in one of the great biodiversity hotspots of the world.  Northern Vietnam is on the edge of Sundaland, a name for the vast expanse of what used to be land connecting the Southeast Asian mainland to Borneo and the Indonesian islands, now mainly under water and expressed as the Sunda Shelf.  During the last ice age this is thought to have been a broad grassland spotted with mountain forests and laced with broad rivers.  For nearly 100,000 years plants and animals moved back and forth across this landscape, becoming wide-spread and subsequently isolated as the rising seas flooded the lowlands, leaving the complex arrangement of islands and peninsulas we now see.

This exposure and inundation of land in this part of the world has been taking place for a long time.  This combined with the vigorous tectonic activity of the region has led to a wonderfully complex region topographically, and subsequently (or in conjunction) biologically.

Sundaland showing current and proposed past rivers

Sundaland showing current and proposed past rivers (source)

This submerged region is now thought to be the cradle of the Asian population, the “Out of Sundaland Theory”, although there is a competing “Out of Taiwan Theory” as well.  Where I will be working is only loosely in former Sundaland, a melding point between Sundaland and the complex geography of Southern China and Northern Laos.  In any event hominids, and later humans have been exploring and living in South East Asia for a long time, and that span of time has allowed tremendous cultural and linguistic complexity to develop as well.  This is one of the places that our most successful and long-lived hominid ancestors, Homo erectus, lived.

I will be on the edge of this region, just off the coast of northern Vietnam, on the northern margin of the Red River delta not too far from the Chinese border.  The location is Ha Long Bay, a dramatic karst landscape that is both mature and submerged.  The ingredients for a karst landscape are limestone and time, lots of both.  In some parts of the world the only signifying features of kart landscapes are rich soils (lots of cations) and , if it is wet, periodic sinkholes.  Where water is in abundance caves are common, as groundwater is often mildly acidic which erodes the limestone.  Over time continued erosion wears down the limestone bedrock to such a great degree that all that is left are startlingly steep sided hills, separated by flat valleys.  This is a mature karst landscape.  In Sundaland some of these mature karst regions were flooded when the sea level rose resulting in a dream-like landscape that looks like something Hayao Miyazaki would imagine if he were to direct a pirate movie.

Ha Long Bay mature submerged karst landscape (source)

Places like Ha Long Bay are excellent examples of island biogeography.  Islands are often home to endemic species, the tortoises and finches on the Galapagos Islands are the classic example of this, made famous by Darwin.  Animals and plants that make their way to an island, or are trapped by rising seas or continental drift become isolated and diverge from their ancestors.  This is the essence of island biogeography and the recognition of how finch beaks on the Galapagos changed in response to the limited food sources available on the islands helped Darwin to recognize how evolution takes place.  My personal hero in the tale of evolution, Wallace, worked in the submerged island remnants of Sundaland and experienced the same insights as Darwin.  Ha Long Bay is a small area, but has its own endemic species, many of them we probably know little to nothing about.

One we do know of is the Cat Ba Langur (Trachypithecus poliocephalus poliocephalus), a dark haired leaf eating monkey with white heads and brilliant golden furred babies.  They are found only on Cat Ba Island, one of the largest islands in the Ha Long Bay, and are critically endangered.  Critically is an understatement, there are less than a hundred of these primates alive in the world.  And. That. Is. All. There. Are.

Cat Ba Langur on limestone cliffs. [EDIT – the photo I previously had here was of the closely related White-Headed Langur – it was mislabeled as a Cat Ba Langue at the source I found it]

In 25 hours I get on a flight to Hanoi to take part in an effort to both keep these primates from going extinct and to conserve the biodiversity of the island.  There are a lot of moving parts in the project, many partners at all levels, and only a few of us on the ground to keep everything running smoothly.

I’m excited, eager, and somewhat intimated.  I leave tomorrow.

The Beneficial Lady Beetles: Good Luck Bugs or God’s Little Cows

J.B.S. Haldane, one of the founders of population genetics, is credited with saying, “If one could conclude as to the nature of the Creator from a study of creation it would appear that God has an inordinate fondness for stars and beetles.”  Like most quotes attributed to famous people, it is probably apocryphal, but the point is valid.  There are a lot of Coleoptera species in the world, not as many as there are stars in the sky, but 1 out of 4 animal species in the world is a beetle of some sort. Many people experience an inordinate queasiness around insects and other arthropods.  There are a few species, however, that rarely elicit distaste.  Of these the Coccinellidae or  Ladybugs (also called Lady Birds and Lady Bird Beetles) are particularly adored.  The most iconic of these are the jewel-like red and black spotted types, of which there are many.  All told there are some 5,000 species of ladybugs around the world, not all of which are red, around 450 in North America, and approximately 175 species in California alone.  All ladybugs share the endearing, rounded shape that their name, Coccinellidae (meaning “little sphere” – Note: some sources suggest that this name means “scarlet”), derives from.  These are primarily solitary little beetles that are found nearly everywhere there are a lot of plants, especially in gardens, fields, grasslands, and shrublands.

Convergent Ladybug (Hippodamia convergens) on manzanita leaf

Convergent Lady Beetle (Hippodamia convergens) on manzanita leaf

The rounded shape that gives ladybugs somewhat of a bumbling appearance is actually highly effective armor to protect them from ants.  “Why do they need protection from ants?” one might ask.  Well, contrary to their appearance, they are fierce and merciless predators, specializing in aphids.  Hungry ladybugs will eat a wide variety of insects, but to reproduce they must eat aphids and eat large quantities of them.  An adult Convergent Lady Beetle (Hippodamia convergens), a common and easily identifiable ladybug found in the Americas from Canada to northern Bolivia, eats 40-75 aphids a day with the larvae eating only slightly fewer.  Aphids have a special relationship with ants. Aphids by themselves are small, defenseless, and relatively harmless, but, as any gardener or farmer knows and fears, they can very quickly reach immense numbers.  Aphids live off of plant sap, sinking their mouthparts into soft plant tissue like miniature vampires.  Plant sap is high in sugars that the aphids excrete in the form of honeydew.  Ants, like many animals, have an affinity for sugar and collect the sweet honeydew from aphids, in some cases treating them not so differently from the way we treat free range cows.  In exchange for honeydew the ants protect the diminutive aphid herds from predators.  Predators such as the voracious and heavily armored ladybug. Farmers and gardeners have a particular fondness for ladybugs as they can potentially save a whole crop from devastation.  The name “Ladybug” or “Lady Beetle” supposedly derives from vast numbers of ladybugs descending on pest infested fields after villagers prayed to the Virgin Mary to protect their crops.  In Germany one of the names was Mary’s Chicken, in Sweden The Virgin Mary’s Golden Hen, in Spain Gods Little Cow, in Turkey they have the name Good Luck Bug, and in Yiddish they are called Moses’s Little Cow.  In Russia seeing a ladybug indicates that a wish will soon be granted or is an indication to make a wish.  Before Christianity took over northern Europe their name was tied with the Norse goddess Frejya rather than with Mary.  Nearly all the names for ladybugs indicate how well respected and loved they are, though there are a few names reflect the burning aspect of the chemical defense they use to deter larger predators. The Convergent Lady Beetle is particularly favored by farmers in the US as a natural pest control method.  Despite their solitary nature one acre of alfalfa suffering from an aphid infestation can support up to 50,000 ladybugs by Dr. Kenneth Hagen’s estimate.  Many farmers take preemptive steps to control aphid infestations by releasing ladybugs in bulk, purchasing buckets containing between 70,000 and 80,000 individuals per gallon.

Convergent Ladybug (Hippodamia convergens) in a hibernation swarm.

Convergent Lady Beetle (Hippodamia convergens) in a hibernation swarm.

If ladybugs are solitary, how does one collect 70,000 of them?  They migrate; I’ve mentioned insect migration before, but this is not the extraordinary long distance flight of dragon flies or monarch butterflies.  This is a short migration up into the hills and mountains where the ladybugs cluster in protected areas and wait for the weather to warm up. Ladybugs do not fly if the temperature drops below 55ºF (13ºC) and the Convergent Lady Beetle spends the cooler months in diapause, an insect analogue to hibernation.  In California, Convergent Lady Beetles living in the Central Valley head up into the Sierras while those closer to the coast find local hollows and protected areas to gather in.  They often show fidelity to specific sites and, in the Sierras, can gather in vast numbers.  Individual sites can have as much as 500 gallons of ladybugs, or more than 37 million individuals.  Collectors scoop these ladybugs up and sell them to agriculturalists around the country. In the coastal portions of California the distances the ladybugs travel to wintering sites is not as great and they do not gather in the same density.

Hippodamia convergens in Redwood Regional Park

Hippodamia convergens in Redwood Regional Park

One place to see Hippodamia convergens gathering is in Redwood Regional Park in Oakland.  There is one spot that they return to, a glade near one of the streams.  They coat the low growing and dead vegetation, branches, and logs in an intermittent film of slowly moving red gems.

Hippodamia convergens on dead vegetation

Hippodamia convergens on dead vegetation

In some spots they clump like globs of foam stuck to old hemlock stalks, in other areas they gather on lichen covered logs.

Hippodamia convergens on log

Hippodamia convergens on log

They are not completely dormant.  If you sit and watch them for a few minutes you will see them slowly mill about.

Hippodamia convergens on twig

Hippodamia convergens on twig

In a few places they form a nearly even coat over branches.

Hippodamia convergens covering a branch

Hippodamia convergens covering a branch

In other spots they cluster between the stalks of old flower-heads.

Hippodamia convergens on flower head

Hippodamia convergens on flower head

Finding these conglomerations of ladybugs is particularly exciting, in part as it is so shocking even when you are expecting it.  We have so few opportunities to see large numbers of wild animals in their natural environment any more that when we do it is particularly impacting, especially if it is of a type of animal we usually see as solitary individuals.  The ladybugs are also very pretty, which is always a bonus. *** Macro photos taken with a 70-300mm lens and kenko macro-tubes at a high ISO due to the late time of day and shade.

Chert – the birthstone of our species

Few types of stone have as long lasting and intimate relationship with our species as do those of the chert family.  Humans have been using this hard, glassy stone continuously to make tools since the time of Homo habilis, some 1.5-2 million years ago.  Our neolithic ancestors mined chert using fire to crack the stone (see video to see how it was done), at least 33,000 years ago at the Nazlet Khater site in Egypt chert was extracted from subterranean mines,  and flint (a type of chert) was used before we had matches to make fire, today we use crushed chert as the abrasive on some sandpapers, and to extract exquisitely detailed micro-fossils from the distant past.  When I worked as an archaeologist near Santa Barbara most of the projectile points, stone awls, and cutting tools we found were made from chert.

What is this “chert” we have been using so assiduously for the last 2 million years?

Chert is a microcrystalline stone made of silicon dioxide (SiO2) with a cryptocrystalline structure (crystals so fine that they are difficult to see even under a microscope) that lacks cleavage planes.  One of the most useful, for us, aspects of cryptocrystalline materials such as chert is that when they are struck they shatter in a predictable conical manner (conchoidal fracturing).  Obsidian and plate glass share this characteristic, making them and chert excellent for making extremely sharp stone tools.  Chert is more common than obsidian, but still rare enough that it was traded over great distances.  Another beneficial aspect of chert is that it is extremely hard, raking a 7 on the Mohs scale.

A number of well known minerals fall into the chert category: flint, jasper, radiolarite, chalcedony, agate,  and onyx are all types of chert, each with specific characteristics that give them enough difference from each other to warrant specific names.  The famous (and expensive) sharpening stones from Arkansas are made from novaculite, a porous, metamorphosed chert that makes an excellent abrasive.  Flints tend to be high quality cherts that are found specifically in chalk or limestone; these are deposited diagenically (via silicon replacement).  Chalcedony, agate, and onyx are a nested subset of minerals with chalcedony, a fibrous form of chert, being the parent of the group.  Jasper is usually found in association with volcanic activity and is sometimes considered to be under the chalcedony subset.  Jasper, agate, and onyx are popular semi-precious stones used for jewelry and sometimes intricately carved.

Red jasper cameo of Medusa by Benedetto Pistrucci (source)

What got me started thinking about cherts once more was a short day-hike I took with a friend in the Marin Headlands, those steep sided hills to the north of San Francisco that are so often obscured by the thick maritime fog.

Marin Headlands and the Golden Gate bridge partially hidden by fog

Marin Headlands and the Golden Gate bridge partially hidden by fog

The Northern California coast has a complex geology and is undergoing a number of divergent changes simultaneously.  This is an emergent shoreline (Geology of Northern California chapter 10, page 37), a place where the land is slowly rising in elevation.  Rising lands often suffer from high rates of erosion and the California coast has an even more drastic set of factors contributing to the erosion rare than merely rising land.  The bedrock is fractured by many faults, weakening the stone, earthquakes (most extremely minor) shake rubble loose periodically, and both wind and water eat away at the ocean facing slopes.  In addition, the sea level has risen several hundred feet since the last glaciation twelve thousand years ago, and the surf is greedily pounding on the hills, tearing parts of them away.

If you watched the video you probably noticed that the chert they were mining peeled off in plates, indeed that the whole formation was made up of sheets of stone layered atop each other like pastry dough.  About 50% of rock in the Marin Headlands is chert and has a similar texture.

Radiolarin ribbon chert cliff showing soft folds and a sharp fault-line cut

Radiolarite chert cliff showing soft folds and a sharp fault-line cut

This is ribbon chert, more formally known as radiolarite chert.  It gets the latter name because it is a biogenic stone made from the semi-gelled skeletons of radiolaria, a type of plankton that builds a silica based support structure.  These this rock was laid down over a 100 million year span beginning 200 million years ago and is filled with tiny fossils of the radiolaria.  Supposedly some of these are large enough to see with a standard hand-lens.

The folding tells us something interesting.  The folds in the above photo are smooth, meaning that this probably slumped slowly while it was still ductile.  Portions of the cliff have sharp folds where the rock broke, indicating that those deformations most likely happened more rapidly and after the stone had lost much of its ductility.

Red and greenish/blue indicate iron, either in oxodised or reduced form

Red and greenish/blue indicate iron, either in oxidised or reduced form

Much of the chert here is red, but there are many patches of vibrant blue-green and aqua as well.  The colors in chert indicate trace amounts of other minerals.  The red and the lovely greenish-blue are both indicators of iron, the red indicating that the iron has oxidised, the blue-green that it has been reduced (had the oxygen removed from it).  This is similar to the mottled gleying that one sees in wetland clay soils.  I am particularly fond of the blue and green colors in chert, perhaps because they are a bit more rare than the red.

Close-up of blue/green chert bands

Close-up of blue/green chert bands

The hardness of the chert leads to beaches with an interesting texture of sand, more like tiny glossy pebbles than the standard sand.

Chert sand

Chert sand

The combination of colors on the cliffs, beach, sky, and ocean make for a nice combination as well.

Tennessee Valley beach in the Marin Headlands

Tennessee Valley beach in the Marin Headlands

We have been using chert for nearly as long as we have been using tools, close to 2 million years now with no sign of slowing down.  If our species had a birthstone it would probably be chert.

California Condors, Megafauna, and Trophic Cascades

A long time ago I worked as an archaeologist near Santa Barbara.  I spent most of my days in the field excavating Chumash sites, recording evidence of looting, drawing maps, and hunting for unknown sites.  It was a fun job, I learned a lot, and it was my first exposure to California Condors.

The Chumash left behind a repository of exquisite petroglyphs, painted and carved into the soft sandstone that makes up much of the Transverse Range, an east-west oriented set of coastal Southern California mountains.  One of my jobs was to preserve this rock-art.  In the dust that makes up the floor of the caves and shelters the art is painted lives a bacteria that eats the organic pigments in the paint used by the Chumash.  Visitors would unwittingly kick up the dust, spreading the bacteria and speeding up the degradation of the rock art.  At several sites we paved the floor with stones to trap the dust.  One of these sites was Condor Cave in the San Rafael Wilderness; I’m sure you can guess how it came by that name.

Condor art at Condor Cave – from

It wasn’t until several years later I when was backpacking in the Ventana Wilderness with a friend that I saw my first wild California Condor.  We stopped and sat, mesmerized, watching five large birds swoop and soar around us.  Of course my camera was acting up at the time and the only photos I got were pathetic to say the best.  The experience stuck with me, all the more so because I had been studying anthropology and repercussions of the North American megafauna extinctions.  

About a week ago I was driving from San Francisco to Los Angeles along HWY 1.  It was one of those spectacular California days where the coast is shrouded by pockets of thick fog broken by regions of bright sunlight and the Pacific Ocean lives up to its name lying tranquil in its bed.

Sun, fog, and kelp-beds along the coast between Morro Bay and Big Sur

Sun, fog, and kelp-beds along the coast between Morro Bay and Big Sur

This stretch of road is made up entirely of corners and as I rounded one I saw a pocket of people pulled over in a turn-out looking up at something on the hill-side.   I caught a glimpse of a large bird on the slope, pulled over at the next turn-out, grabbed my camera, and jogged back to find a very calm California Condor sunning itself in the late afternoon light.

California Condor soaking up the last of the sunlight

California Condor (Gymnogyps californianus) soaking up the last of the sunlight

The California Condors are in rough shape.   DDT, hunting by mis-informed ranchers who believe that condors killed calves, egg collecting, habitat loss, and lead-poisoning are all implicated in modern times for the low numbers of  the California Condor (Gymnogyps californianus).   Additionally, these long-lived birds have small clutch sizes (few eggs per breeding cycle) and reproduce extremely slowly; so slowly that a 1996 study by the Fish and Wildlife department found that it would take 1800 years at the current population growth rate of 1.0003 to achieve a stable wild population of 150 individuals.  This low population growth rate is part of why there is a captive breeding program.

California Condor (Gymnogyps californianus) in the Los Padres National Forest

California Condor (Gymnogyps californianus) in the Los Padres National Forest

In historic times the California Condor ranged from British Columbia to Baja, but during the 19th century its range was rapidly diminished to include only California.  Through captive breeding and release strategies the range has been re-expanded and now includes Arizona, northern Mexico, and a little of Utah, in addition to California.  These birds have what is known as a “relict distribution”, that is, they occupy only a fragment of their former range.

California Condor range map - from: IUCN Redlist

California Condor range map – from: IUCN Redlist


While it is certainly true that lead poisoning, DDT, and all the rest have been massively detrimental to present day condors this overlooks a very important aspect of the condor niche.  These are large birds, the largest flying birds in North America, with up to a 9.5 foot (2.9 me) wingspan and weighing up to 23 pounds (10.4 kg).  These birds are meat eaters and they need a lot of meat.  The historic population was highest along the coast, where aquatic megafauna would, and still does wash up on the beach.  Beached whales, elephant seals, sea lions, dolphins, seals, and large fish may be disturbing to see, but they provide a wealth of food for bears, foxes, coyotes, weasels, wolves, eagles, gulls, ravens, and condors.  It is true that there are still large gatherings of sea mammals along the coast, but it is also true that there are far fewer of them than there used to be and this has imparted an additional stress to the condors, among other species.

Northern Elephant Seals (Mirounga angustirostris) on the California Coast

Northern Elephant Seals (Mirounga angustirostris) on the California Coast

For birds further inland other sources of meat were, and are important.  Terrestrial megafauna is what fed and feeds inland condors.  We have nowhere near the diversity nor the biomass of large free-living terrestrial animals than we did even a few hundred years ago, let alone what we had when humans first arrived in North America.  Shortly after the arrival of humans most of the large animals, the megafauna (generally being defined as an animal with a body-mass greater than 100 pounds (45 kg) began going extinct.  The giant beavers disappeared, the mastodons vanished, the giant sloths, camel relatives, giant tortoises, horses, and various species of deer were wiped from the continent, and along with those animals also went other animals that relied upon them; dire wolves, saber-toothed cats, short-faced bears, American lions, American cheetah, tetratorns (think condors on steroids), dung beetles, and condors.

Tule Elk (Cervus canadensis ssp. nannodes) being restored to California grasslands

Tule Elk (Cervus canadensis ssp. nannodes) being restored to California grasslands

There is vociferous disagreement as to why the megafauna went extinct, but many, if not most, scholars believe that humans hunted these animals to extinction.  Humans arrived during an ice age and the rapid change in climate (rapid in an evolutionary sense) may have placed the animal populations in a position where enthusiastic hunting had a greater impact than would be otherwise expected; but whatever the exact details the short story is that humans arrived and within a few thousand years a majority of the megafauna went extinct.  This triggered what is known as a “trophic cascade”.

You can think of an ecosystem as being analogous to a game of Jenga.  All together the blocks form a solid tower, but as you remove blocks (species) the tower (ecosystem) becomes more and more unstable.  Eventually one too many blocks is removed and the whole structure comes tumbling down.  In essence, this is what a catastrophic trophic cascade looks like.  So many animals were removed from the ecosystem that now, eleven thousand years later, we are still seeing some of the effects.  Just as blocks you never touched in the Jenga game come tumbling down, species of plants, insects, and animals that were never hunted went extinct or had their life patterns radically altered.  Some plants lost their ability to disperse their seeds, forests and grasslands were no-longer grazed as heavily and the composition of species changed drastically, watersheds and rivers changed their patterns, soils changed as they were walked upon by different animals with different behaviors, concentrations of bacteria and fungus changed, altering soil and groundwater chemistry.  Trophic cascades are a big deal.  They are ongoing, but operate in the background, running smoothly and unnoticed until something breaks the chain of events and the whole tower of blocks comes tumbling down.

The current narrow range of Condors is due, in part to the cascading effects of the megafuna extinctions and more recent changes brought by colonizing Europeans.  We know from the fossil record that prior to the megafauna extinctions several species of condors lived in North America over a range that includes the historic range of the California Condor and stretched across the southern states and up the east coast to New York.

Prehistoric US fossil sites for North American condors, courtesy of the San Diego Zoo library

Seeing the California Condors in the wild is like catching a brief glimpse into the distant past, a time when North America had wildlife diversity to rival that of Africa.  The fate of the condors is far from certain.  They are from a time and place that no-longer exists and it remains to be seen if they can adapt to the world as we have made it, even with our assistance.  I hope the condors do succeed, the world is a richer place and better place for their presence.

Preening in the late afternoon sun

Preening in the late afternoon sun

Tides, Why Tide Charts Don’t Average to Zero, and Agendas

Tides are an important part of life on earth. Earthly tides are primarily governed by the moon, a result of Lunar gravity tugging on the planet as the Earth spins along side of our over-sized neighbor.

A few days after the 2013 "supermoon"

A few days after the 2013 “supermoon”

Tides affect both the earth’s crust (raising it enough so that large particle accelerators must be designed with the geo-tide in mind) and, more familiarly, the oceans. Technically speaking, all bodies of water are affected by the tides, but the large tides experienced by coastal dwellers is a result not only of the Earth-Moon-Sun gravitational dynamic but of resonance, coastline shape, and of characteristics of the ocean floor.

Resonance is simply the self-reinforcing effect of synchronization. The most familiar form of resonance for most people may be pumping your legs on a swing. If your timing is right the small amount of energy added to the pendulum motion by pumping your legs will lift you higher and higher. If your timing is off you can kill your speed and come to a stop. You can do the same with your hand and a basin of water, a small amount of hand motion will quickly wind up sloshing water out of a bathtub. Swings, tides, and lasers work on this principle of resonance.

The shape of the coastline and the depth of the ocean floor can concentrate or diffuse tides as well, focusing or dispersing the vast energies at play. This is why the tides in places with fjords like British Columbia and Norway can be so dangerous.

I grew up near the ocean and spent a lot of time watching the ocean and exploring tidepools and the rocky beaches of the California coast.

Mussels anchored on exposed rocks in the intertidal zone.

Mussels anchored on exposed rocks in the intertidal zone.

The interesting part of the coast was not the sandy beaches, but the craggy high surface areas that trapped pools of water. All sorts of creatures live in these pools. Strange and wonderful creatures like the Gumboot Chiton, Cryptochiton stelleri, large molluscs that crawl out of the water at low tide to feed on exposed seaweed.

Cryptochiton stelleri, or Stellars's Hidden Chiton, so named because the characteristic eight bony plates are hidden under rugose red skin

Cryptochiton stelleri, or Stellars’s Hidden Chiton, so named because the characteristic eight bony plates are hidden under rugose red skin

In tidepools I have found and caught octopus, eels, and fish, but two of the most common residents are Shore Crabs

Shore Crab, a common California coast resident

Shore Crab missing an arm, a common California coast resident

and anemones, both hovering between the scavenger and hunter niches.

Anemones: close-up of arms

Anemone: close-up of arms

These and many other creatures live in what is known as the intertidal zone, the region of the coast that is above low tide and below high tide. This is an area of tremendous free energy. Energy is a two edged sword as any scientist or engineer can attest to. Energy makes all things possible, and most things can be broken down into either growth or destruction. Creatures that live in the intertidal zone reap the benefit of straddling two environments, feasting on the windfall of both, but the fierce waves and tides also expose them to the dangers of being left to suffocate in water, desiccate in the sun, be torn from holdfasts, and fall prey to other adaptable creatures. Excellent potential for great growth or swift destruction.

In the intertidal zone there are bands of life that roughly conform to the amount of time spent out of water. Mussels and barnacles occupy the upper reaches and are the most familiar.

Mussels and Gooseneck Barnacles on exposed rocks.  Both are tasty to eat.  Mussels are commonly eaten in the US and Gooseneck Barnacles fetch high prices in Spain, where people risk their lives to collect them.

Mussels and Gooseneck Barnacles on exposed rocks. Both are tasty to eat. Mussels are commonly eaten in the US and Gooseneck Barnacles fetch high prices in Spain, where people risk their lives to collect them.

Lower down, in some places, Sea Palm grows in dense stands, often damaged by the waves.

Sea Palm (Postelsia palmaeformis), the only species of this kelp and one of the few that can live for extended times out of water

Sea Palm (Postelsia palmaeformis), the only species of this kelp and one of the few that can live for extended times out of water

At each level a different selection of species dominates creating a many-layered composite of ecotones, much like a mountain in miniature. The vertical ranges for these species collections is so narrow that it can be used to track sea level changes.

If you want to see nudibranchs, octopus, and sandcastle worm, then when do you go to the coast?

sandcastle worm (Phragmatopoma californica) colony

Sandcastle Worm (Phragmatopoma californica) colony

Clearly you go at low tide… but what does this mean?

One of the things that bothered me about tide-charts (like the one below) is that if you average the high and low tides you do not get zero.

Graphical tide chart made with the TideTrac app

Graphical tide chart made with the TideTrac app

I went out a while back to experiment with day-time long exposure photos. This is the tide chart for the day. Notice that the lowest tide of the day is still +0.4 feet (12cm)? The average tide for the day is +2.9 feet, nearly a meter. What is that all about?

The answer is that tide charts were designed for sailors, not tide-poolers or surfers. Tide charts are set by a datum, one of 17 potential datums, that all are based off of the LOWEST tides, not the average tide. For a sailor who wants his boat to stay in the water and not be slammed against rocks, this is important.

Even a small bump carries a lot of energy

Even a small bump carries a lot of energy

For the rest of us, it is a little non-intuitive. We have picked the lowest tide as the datum because that is what was important to the people making the charts at the time. If it had been house contractors instead, the datum would have been the highest tides. Tide-poolers would probably have picked the average tide as the datum, making it easy to determine when the most species would be exposed at any given moment.

There is a lesson here; be wary of maps and charts. Maps and charts are made to tell a specific story, a story with a perspective, a message, and an agenda. Like an advertisement on TV or a political speech, it is important to be aware of both the audience and the proponents of the product. And in truth, there is little that is more political than maps and charts.

Oh, the long exposure photos turned out great.

Ten seconds of waves washing in and out during the day

Ten seconds of waves washing in and out during the day


Note: for those of you who look at the full-sized photos, several of these have been pulled from my archives and were taken with my first digital camera; a Canon ELPH from the early 2000s. A great little camera, but of a disappointingly low resolution.