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I've written before about the rocky intertidal as a habitat where livable space is in short supply. Even areas of apparently bare rock prove to be, upon closer inspection, "owned" by some inhabitant or inhabitants. That cleared area in the mussel bed? Look closely, and you'll likely find an owl limpet lurking on the edge of her farm.

See?

Owl limpet at edge of her territory, a clear area surrounded by mussels.
Owl limpet (Lottia gigantea) on her farm at Natural Bridges
2017-04-01
© Allison J. Gong

And of course algae are often the dominant inhabitants in the intertidal.

Assemblage of algae in the intertidal
Assemblage of algae north of Waddell Creek
2020-06-09
© Allison J. Gong

When bare rock isn't available, intertidal creatures need other surfaces to live on. To many small organisms, another living thing may be the ideal surface on which to make a home. For example, the beautiful red alga Microcladia coulteri is an epiphyte that grows only on other algae. Smithora naiadum is another epiphytic red alga that grows on surfgrass leaves.

We describe algae that grow on other algae (or plants) as being epiphytic (Gk: epi "on" + phyte "plant"). Using the same logic, epizooic algae are those that live on animals. In the intertidal we see both epiphytic and epizooic algae. For many of them, the epizooic lifestyle is one of opportunism--the algae may not care which animal they live on, or even whether they live on an animal or a rock. Some of the epiphytes, such as Microcladia coulteri, grow on several species of algae; I've seen it on a variety of other reds as well as on a brown or two (feather boa kelp, Egregia menziesii, immediately comes to mind). Smithora naiadum, on the other hand, seems to live almost exclusively on the surfgrass Phyllospadix torreyi.

Animals can also live as epiphytes. The bryozoan that I mentioned last time is an epiphyte on giant kelp. Bryozoans, of course, cannot move once established. Other animals, such as snails, can be quite mobile. But even so, some of them are restricted to certain host organisms.

The aptly called kelp limpet (Discurria insessa), lives only on the stipe of E. menziesii, the feather boa kelp. Its shell is the exact same color as the kelp where it spends its entire post-larval life. Larvae looking for a place to take up a benthic lifestyle settle preferentially on Egregia where adult limpets already live. It's a classic case of "If my parents grew up there it's probably a good place for me."

Limpet on stipe of feather boa kelp
Discurria insessa on stipe of Egregia menziesii
2020-06-07
© Allison J. Gong

The limpets cruise up and down the stipe, grazing on both the epiphytic diatoms and the kelp itself. They can make deep scars in the stipe and even cause breakage. Which makes me wonder: What happens to the limpet if it ends up on the wrong end of the break? Does it die as the broken piece of kelp gets washed away? Can it release its hold and find another bit of Egregia to live on? Somehow I doubt it.

Discurria insessa on stipe of Egregia menziesii
2018-05-16
© Allison J. Gong

The last time I was in the intertidal I encountered another epiphytic limpet. Like the red alga Smithora naiadum, this snail one lives on the narrow leaves of surfgrass. It's a tiny thing, about 6 mm long, and totally easy to overlook, given all the other stuff going on in the tidepools. But here it is, Tectura paleacea. Its common name is the surfgrass limpet, which actually makes sense.

Top view of surfgrass limpet on leaf of surfgrass
Surfgrass limpet (Tectura paleacea) on surfgrass (Phyllospadix torreyi) at Davenport Landing
2020-07-07
© Allison J. Gong

Tectura palacea feeds on the microalgae that grow on the leaves of the surfgrass, and on the outer tissue layer of the plant. They can obviously grow no larger than their home, so they are narrow, about 3 mm wide. But they are kind of tall, although not as tall as D. insessa.

Lateral view of surfgrass limpet on leaf of surfgrass
Surfgrass limpet (Tectura paleacea) on surfgrass (Phyllospadix torreyi) at Davenport Landing
2020-07-07
© Allison J. Gong

Cute little thing, isn't it? Tectura palacea seems to have avoided being the focus of study, as there isn't much known about it. Ricketts, Calvin, and Hedgpeth write in Between Pacific Tides:

A variety of surfgrass (Phyllospadix) grows in this habitat on the protected outer coast; on its delicate stalks occurs a limpet, ill adapted as limpets would seem to be to such an attachment site. Even in the face of considerable surf, [Tectura] palacea, . . . , clings to its blade of surfgrass. Perhaps the feat is not as difficult as might be supposed, since the flexible grass streams out in the water, offering a minimum of resistance. . . The surfgrass provides not only a home but also food for this limpet, which feeds on the microalgae coating the blades and on the epithelial layers of the host plant. Indeed, some of the plant's unique chemicals find their way into the limpet's shell, where they may possibly serve to camouflage the limpet against predators such as the seastar Leptasterias hexactis, which frequents surfgrass beds and hunts by means of chemical senses.

And that seems to sum up what is known about Tectura palacea. There has been some work on its genetic population structure, but very little about the limpet's natural history. The intertidal is full of organisms like this, which are noticed and generally known about, but not well studied. Perhaps this is where naturalists can contribute valuable information. I would be interested in knowing how closely the populations of T. palacea and Phyllospadix are linked. Does the limpet occur throughout the surfgrass's range? Does the limpet live on both species of surfgrass on our coast? In the meantime, I've now got something else to keep my eye on when I get stranded on a surfgrass bed.

I'm not the world's most diligent user of iNaturalist, but I do try to upload observations after I've been tidepooling or hiking or poking around outdoors. The other morning I did go to to the intertidal, for only the second low tide series since the COVID quarantine began. State park beaches were closed over the Independence Day holiday weekend, to all except people who could walk there. This rather limited my options, but it was fine because I hadn't been to Natural Bridges in quite a while. It's a site I know well, so I also used the trip to record some video clips to use when I teach Marine Biology in the fall.

My favorite iNat observation for the day is this one:

Bryozoan on a piece of kelp in the shell of a mussel in the mouth of an anemone
2020-07-06
© Allison J. Gong

It's not the prettiest photo, or even the best of the ones I took today. What I like is that it shows four different organisms and demonstrates a few ecological concepts. Let me explain.

The first two organisms are the bryozoan Membranipora membranacea encrusting a small piece of giant kelp Macrocystis pyrifera. This bryozoan really likes to live on giant kelp. In the late summer and fall, it is not uncommon to see kelp thalli so heavily encrusted that blades become brittle and break. The bryozoan also makes the overall kelp thallus both heavier and more brittle than usual, contributing to the annual break up when the winter storms arrive.

The third organism is the mussel, Mytilus californianus, which is probably just an empty shell with the piece of kelp jammed inside.

The fourth organism (or first if you're going from largest to smallest) is the anemone. It is a giant green anemone, Anthopleura xanthogrammica. It's not that uncommon to see them eating mussels, as they are opportunistic predators that will consume anything unfortunate enough to fall onto them. If the mussel shell in indeed empty, then it won't provide the anemone with much in the way of food. However, the bryozoan on the kelp, and even the kelp itself, will. The anemone's gut will be able to digest both of them.

2

For some reason, the barn swallows at the marine lab like building their nests above doors. It seems that little 1/2-inch ledge of the door frame provides support for the mud nest. And the birds don't always choose little-used doors, either. This year a pair constructed their nest above one side of a double-door that people walk through all day. The mother laid and incubated her eggs, but would occasionally get flushed off the nest if someone came through the door. I always tried not to disturb her any more than necessary. The animal is always right, so I figured she knew what she was doing.

The eggs hatched about a week ago, I think. The mom would sometimes leave the nest when people approached, and even though I couldn't see anything in the nest I'd hear little cheeps. Earlier this week I thought I could see little heads poking above the edge of the nest.

It seems there are three baby birds in this nest!

Trio of baby barn swallows in nest
Trio of nestling barn swallows (Hirundo rustica)
2020-06-27
© Allison J. Gong

I haven't spent much time watching the nest closely, because I don't want to scare the mother off and keep her away. Today I was lucky and stuck around just long enough, and with the big camera at hand, to capture both parents returning to feed the babies. The first parent arrived with an insect and landed on the nest. The other parent alit on the door frame.

Parent barn swallows return to the nest
Parents arrive at the nest
2020-06-27
© Allison J. Gong
Parent with insect, and babies waking up
2020-06-27
© Allison J. Gong
Baby barn swallow opening mouth to be fed
Open wide!
2020-06-27
© Allison J. Gong
Parent barn swallow feeding a nestling
So many gaping mouths to feed!
2020-06-27
© Allison J. Gong

After depositing the insect into one of the gaping yellow mouths, the first parent flies off. The second parent doesn't seem to have anything to offer the babies, though.

Three nestling barn swallows and one parent
Not enough bugs to go around
2020-06-27
© Allison J. Gong

Ooh, maybe this parent has food!

Three nestling barn swallows, and second parent flying towards nest
Oh, maybe Dad has something for us!
2020-06-27
© Allison J. Gong

The second parent lands on the nest. . .

Parent barn swallow on nest containing nestlings
We want more!
2020-06-27
© Allison J. Gong

. . . and promptly takes off again. . .

Parent barn swallow leaving nest containing nestlings
Alas, no luck this time
2020-06-27
© Allison J. Gong

. . . leaving the babies alone in the nest again.

Three nestling barn swallows showing yellow gapes
Hungry nestling barn swallows
2020-06-27
© Allison J. Gong
Three nestling barn swallows
2020-06-27
© Allison J. Gong
Three nestling barn swallows
2020-06-27
© Allison J. Gong
Three nestling barn swallows
2020-06-27
© Allison J. Gong

These babies still need to grow feathers, although they are clearly big enough to thermoregulate without a parent sitting on them. Growing feathers takes a lot of metabolic energy, and aside from when the parents arrive with food the nestlings will sleep. But it's funny. They seem able to keep an eye (or maybe an ear) out for the parents flying around, and whenever one flies past the doorway they all perk up and start cheeping. There are lots of swallows at the marine lab right now, and I wonder if these babies can identify their parents from among all the other adults in flight.

They'll grow fast, being fed frequently by their parents. They'll have to get big and strong, to prepare for their migratory trip south in the fall I've never noticed exactly when they leave, I think because by the time they head south they've dispersed from the nest site. I always look forward to their return in the spring, though.

Every year we are fortunate to watch a pair of red-tailed hawks (Buteo jamaicensis) raise young in a tree across the canyon. We're not always sure if the parents are the same birds every year, and I think this year's female is a different bird from last year. Her mate may be the male who has used this nest site for a couple of years now, but again, we don't know.

This year the parents raised three youngsters, who have just begun leaving the nest. They prepare for their first flights by making their way to the edge of the nest and flapping their wings to exercise the flight muscles. This is usually fun to watch, as they don't seem to care whether or not a sibling is in the vicinity. This flapping activity begins before the bird is fully feathered, and they look like awkward punk-rocker teenagers, trying to be cool and not even close to pulling it off.

The hawk nest is in a eucalyptus tree. As the time to fledge approaches, one or both of the parents often perches at the top of a nearby cypress tree. Usually the youngsters' first flights are to the cypress tree. Cypress trees may be the ideal location for fledging, because they have lots of soft-ish branches to fall on when the birds biff the landing. The first flights don't go far from the nest, and the birds end up hopping along branches as they flap their wings. So they are called branchers.

With raptors, the females are bigger. Males tend to leave the nest before their sisters, who have more growing to do, so we always assume that the first one to depart is a boy. This year the females lagged by only a day or so behind their brother. And all three of them seem to be progressing pretty quickly, compared to cohorts we've watched in previous years. Good little branchers!

Pair of sibling red-tailed hawks (Buteo jamaicensis), or branchers
2020-06-12
© Allison J. Gong

We watched these two for a while in the early evening. I don't know where the third one was. The branchers watch their parents soar around effortlessly. Here they are at the very top of the cypress tree:

Pair of sibling red-tailed hawks (Buteo jamaicensis), or branchers
2020-06-12
© Allison J. Gong

Okay, my digiscoping skills need work. I did, however, get lucky enough with the spotting scope and my phone to catch a few video clips.

You can see them trying to maintain their footing as the wind blows the tree around. They're able to use their wings for balance, but then they catch a little lift and get knocked about. In the second clip one of the birds is hanging out when its sibling crashes into it. If they were human teenagers, you'd hear one yelling "Look out below!" while the other hollers "Get off me!" Yeah, landing is toughest part of flight!

Over the next few weeks the branchers will get better and better at landing, and their flights will get longer. They will learn how to find thermals and soar. Their parents will continue to provide food for them, but at some point the kids will learn how to hunt on their own. Rodents of the neighborhood, look out! Eventually the branchers will be as badass as their parents. Then they'll disperse to find territories of their own.

Every year, in June, my big whelk lays eggs. I have a mated pair of Kellettia kellettii living in a big tub at the marine lab. I inherited them from a lab mate many years ago now, and they've been nice pets. They've lived together forever, and make babies reliably. As June rolls around I start looking for eggs. This year I want to document the entire process, from egg-laying to larval development. Fortunately, I had the foresight to photograph the parents in May, as I didn't want to disturb the female once she began laying.

The female is significantly larger than the male. I know the big one is the female because that's the one that lays the eggs. I've never managed to catch the whelks copulating, but given the female's track record they either copulate regularly or she is able to store sperm for a long period of time.

In any case, she started laying eggs today. I went in to check on them and there she was!

Female whelk laying eggs
Female whelk (Kellettia kellettii) laying eggs
2020-06-12
© Allison J. Gong

I know from previous years that it can take over a week for the female to lay her entire clutch of eggs. Each of those pumpkin seed-shaped objects is an egg capsule, containing a few dozen embryos. The newly lain capsules are white, as you see above, and will gradually get darker as the embryos develop into larvae. The mother will lay the eggs and then depart. When the larvae are ready to leave the capsule, a small hole will wear through in the top of the capsule and the larvae will swim out. More on that later, hopefully.

I took some time-lapse video of the female, and was able to record her moving over the egg capsules and then leaving. I'd also put some food in the tub, and I think she got distracted.

I think it's really cool to see how well the snail can swivel around on her foot. Snails are attached to their shell at only a single point called the columella, the central axis around which the shell coils. Some snails can extend quite far outside the shell, and they can all pull inside for safety. The dark disc on the back of the foot is the operculum that closes up the shell when the snail withdraws into it.

Tomorrow when I check on things at the lab I'll see if she has resumed laying.

2

I've always known staurozoans (Haliclystus 'sanjuanensis') from Franklin Point, and it goes to reason that they would be found at other sites in the general vicinity. But I've never seen them up the coast at Pigeon Point, just a short distance away. At Franklin Point the staurozoans live in sandy-bottom surge channels where the water constantly sloshes back and forth, which is the excuse I've always used for my less-than-stellar photographs of them. Pigeon Point doesn't have the surge channels or the sand, and I've never seen a staurozoan there. I'd assumed that the association between staurozoans and surge channels indicated a requirement for fast-moving water.

Turns out I was wrong. Or at least, not completely right.

California coastline from Waddell to Pigeon Point

A few weeks ago I was doing some identifications for iNaturalist, and came upon some sightings of H. 'sanjuanensis' at Waddell Beach. I thought it would be a good idea to check it out--to see whether or not the staurozoans were there, and to see how similar (or not) Waddell is to Franklin Point.

Photos of the sites, first Franklin Point:

Rocky intertidal at Franklin Point
Rocky intertidal at Franklin Point
2020-06-06
© Allison J. Gong

And now Waddell:

Rocky intertidal at Waddell
Rocky intertidal at Waddell
2020-06-09
© Allison J. Gong

They don't actually look very different, do they? But I can tell you that the channels at Franklin Point get a lot more surf action, even when the tide is at its absolute lowest, than the channels at Waddell. When we were at Waddell yesterday the channels were more like calm pools than surge channels. It sure didn't look like staurozoan habitat to me.

Which just goes to show you how much I know. It took a while, but we found lots of staurozoans at Waddell! And since the water is so much calmer there, picture-taking was a lot easier. The animals were still active in their own way, but at least they weren't being sloshed around continuously.

Staurozoan attached to red algae at Waddell
Staurozoan (Haliclystus 'sanjuanensis') at Waddell
2020-06-09
© Allison J. Gong

And a lot of them had been cooperative enough to pose on pieces of the green algae Ulva, where they contrasted beautifully.

Staurozoan attached to green alga at Waddell
Staurozoan (Haliclystus 'sanjuanensis') at Waddell
2020-06-09
© Allison J. Gong
Staurozoan attached to green alga at Waddell
Staurozoan (Haliclystus 'sanjuanensis') at Waddell
2020-06-09
© Allison J. Gong

I was even able to capture a few good video clips!

Staurozoans at Waddell
2020-06-09
© Allison J. Gong

So, what have I learned? Well, I learned that I didn't know as much as I thought I did. And that's a good thing! This is how science works. Understanding of natural phenomena increases incrementally as we make small discoveries that challenge what we think we know. With organisms like these staurozoans, about which very little is known anyway, each observation could well reveal new information. The observations I made at Waddell have been incorporated into iNaturalist to join the ones that were made back in May, so little by little we are working to establish just where staurozoans live and how common they are. Maybe they aren't quite as patchy and ephemeral as I had thought!

2

This weekend we have some of the loveliest morning low tides of the year, and fortunately the local beaches have been opened up again for locals. The beaches in San Mateo County had been closed for two months, to keep people from gathering during the pandemic. For the first time in over a year I was able to get out to Franklin Point to check on the staurozoans. These are the elusive and camera shy animals that we don't know much about, except that they are patchy in both space and time.

Yesterday the beach at Franklin Point was quite tall, as a good meter or so of sand had accumulated. This is a normal part of the seasonal cycle of sand movement along the coast--sand piles up in the summer and gets washed away during the winter storms. The rocks that you can see only the tops of in this photo would be much more exposed in the winter.

Beach and rocks at Franklin Point
2020-06-06
© Allison J. Gong

It took a while to find the staurozoans. Every time I visit Franklin Point it takes my search image a while to kick into gear, but each time I find the staurozoans my intuition gets a teensy bit better calibrated. As usual, the staurozoans were very patchy. I'd not see any in the immediate vicinity, then I'd move a meter or so away and see them all over. Part of that is due to usual honing of the search image, but part of it is that the staurozoans really are that patchy.

Staurozoan (Haliclystus 'sanjuanensis)
Staurozoan (Haliclystus 'sanjuanensis') at Franklin Point
2020-06-06
© Allison J. Gong

They are always attached to red algae, often the most diaphanous, wispy filamentous reds out there. And they don't seem to like pools, where the water becomes still for a few moments between save surges. No, they like areas where the water sloshes back and forth constantly.

You can see why it's so difficult getting a decent photo of these animals! They're never still for more than a split-second. Staurozoans may have a delicate appearance, but they're very tough critters. Their bodies are entirely flexible, being made out of jelly, and offer zero resistance to the force of the waves. It's a very low-energy way of thriving in a very high energy environment. Who says you need a brain to be smart?

Trio of staurozoans (Haliclystus 'sanjuanensis')
Trio of staurozoans
2020-06-06
© Allison J. Gong

And, of course, they are predators. Being cnidarians they have cnidocytes that they use to catch prey. The cnidocytes are concentrated in the eight pompon-shaped tentacle clusters at the ends of the arms. To humans the tentacles feel sticky rather than stingy, similar to how our local anemones' tentacles feel. Still, I wouldn't want to put my tongue on one of them. The tentacles catch food, and then the arms curl inward to bring the food to the mouth, which is located in the center of the calyx.

The natural assumption to make is that animals tend feed on smaller and simpler animals. Somehow the predator is always considered to be "better" or at least more complex than the prey. I'm delighted to report that cnidarians turn that assumption upside-down. In terms of morphology, at least, cnidarians are the simplest of the true animals. Their bodies consist of two tissue layers with a layer of snot sandwiched between them. They have only the most rudimentary nervous system, and a simple network of fluid-filled canals that function as both digestive and circulatory system. That said, they have the most sophisticated and fastest-acting cell in the animal kingdom--the cnidocyte--which can inject prey with the most toxic venoms in the world.

They don't look like deadly predators, do they?

Staurozoan (Haliclystus 'sanjuanensis')
Staurozoan (Haliclystus 'sanjuanensis') at Franklin Point
2020-06-06
© Allison J. Gong

Cnidarians use cnidocytes to catch prey and defend against their own predators. The cnidocytes of Haliclystus are strong enough to catch and subdue fish. Anything that can be shoved even partway into a cnidarian's gullet will be digested, even if it isn't quite dead yet. This fish was long dead when we saw it, but its tail is still sticking out of the staurozoan's mouth.

Imagine being shoved head-first into a chamber lined with stinging cells. Death, inevitable but perhaps slow to arrive, would be a blessing. Although perhaps less horrific than being digested slowly feet-first.

Speaking of fishing, I caught one of my own yesterday. I saw it fairly high in the intertidal, above the reach of the surging waves. At first I saw only the pale blotchy tail, and even though I recognized it I didn't think it was alive.

Monkeyface prickleback in a tidepool
Hmm, dead or alive?
2020-06-06
© Allison J. Gong

I poked it with my toe. No reaction. Then Alex found a kelp stipe, and I poked it again. It seemed to move a little bit. I'm a lot less squeamish about live things than dead things, so I picked it up to see how alive it was.

It was a monkeyface prickleback (Cebidichthyes violaceus)!

Monkeyface prickleback (Cebidichthyes violaceus)
Monkeyface prickleback (Cebidichthyes violaceus) at Franklin Point
2020-06-06
© Allison J. Gong

Monkeyface pricklebacks are common enough around here that people fish for them. They (the pricklebacks) hide in crevices in the intertidal. Like other intertidal fishes, they can breathe air and are well suited to hang out where the water drains away twice daily. I put this one in a deeper pool and watched it slither away into the algae.

Staurozoans found always mean a successful day in the intertidal. Day after tomorrow I'm going to look for them at a different spot. iNaturalist says they're there, and I want to see for myself. I'm not sure exactly where to look, but I know the habitat they like. And even if I don't find them, it'll be a nice chance to explore a new site. Finger crossed!

2

Back in 1994, the U.S. Army base at Fort Ord was closed in one of the base closure events that occur every once in a while. UC Santa Cruz (UCSC) acquired some 600 acres of the former base to establish the Fort Ord Natural Reserve, which serves as an outdoor laboratory and teaching space for students of all ages. University students from UCSC and California State University Monterey Bay (CSUMB) take classes and have internships on the Reserve. Kindergarten students visit the Reserve for what may well be their first experience of Nature. And I take my community college students there every year.

Coastal scrub habitat at Fort Ord Natural Reserve
2020-03-06
© Allison J. Gong

This year, Joe Miller, the reserve manager, had a lot of things for us to learn about, and we were kept busy all day. The first thing we did, after an introduction to the reserve, was hike to the first of several areas where Joe had set some rodent traps the night before.

There were 30 of these Sherman traps to check.

Sherman traps at Fort Ord Natural Reserve
2020-03-06
© Allison J. Gong

They are live traps, baited to lure in a rodent. The doors shut on the rodent once it ventures inside to grab some seed.

There's a super high-tech method to getting a live rodent out of a trap without hurting either the rodent or the human. You hold the trap vertically, open the top end, slip a plastic bag over the open end, make sure there are no escape openings, then flip the trap over so the rodent falls into the bag. And voilà, instant mouse in a bag!

Students observe Joe's mouse in a bag at Fort Ord Natural Reserve
2020-03-06
© Allison J. Gong

Then you work the rodent head-first into a corner of the bag with one hand, and reach into the bag and approach it from the back end. Follow the backbone forward, then grab the rodent by the scruff of the neck.

Joe holds a scruffed California deermouse (Peromyscus maniculatus)
2020-03-06
© Allison J. Gong

Holding a rodent by the scruff of the neck allows the biologist to handle the animal safely and minimizes the probability of getting bitten.

Scruffed rodent at Fort Ord Natural Reserve
2020-03-06
© Allison J. Gong

We caught three or four deermice, but the cutest rodent we saw was a pocket mouse (Chaetodipus californicus). Joe didn't bother with gloves because, as he said, these guys are really mellow. And it really was! He handed it to us and we took turns holding it.

Pocket mouse (Chaetodipus californicus) at Fort Ord Natural Reserve
2020-03-06
© Allison J. Gong

Cute little guy almost fell asleep on a student's arm.

Pocket mouse (Chaetodipus californicus) at Fort Ord Natural Reserve
2020-03-06
© Allison J. Gong

I think it's called a pocket mouse because it's so cute you want to put it in your pocket and take it home.

We had to let the rodents go because Joe had other things for us to do. In addition to the rodent traps, Joe had set up pitfall arrays to catch herps (reptiles and amphibians). A pitfall array consists of two strips of aluminum flashing set up in the shape of a capital T. At each end of the T there is a pitfall trap. The critter runs or slithers along the flashing and then falls into the trap, which is a small bucket buried so the lip is just at ground level.

Joe shows us a pitfall array at Fort Ord Natural Reserve
2020-03-06
© Allison J. Gong
A student checks a pitfall trap
2020-03-06
© Allison J. Gong

We got skunked on the pitfall traps--all of them were empty. We did, however, get to see herps. Joe showed us a couple of tiger salamanders, which he had permits to keep as teaching animals. These two animals are hybrids between the native tiger salamander (Ambystoma californiense) and a salamander that was introduced from Texas into California to be used as bait. As happened quite often, the bait species took hold in its new habitat and is proving to be a nuisance. In their larval stage they are voracious predators, gobbling up the larvae of other amphibians including those of endangered species such as the red-legged frog. In the area of FONR, pretty much all of the tiger salamanders are hybrids to some degree.

Joe's two "pet" salamanders are very cute!

As with all other amphibians, tiger salamanders require a variety of habitats to complete their life cycle. They reproduce in water, and the larvae live in water. California has distinct wet and dry seasons, and the salamanders must find vernal pools where the water will last long enough for their larvae to metamorphose into the terrestrial adult form. Sometimes the pools don't persist long enough, and in very dry years the pools may not form at all. During the dry season, tiger salamanders may estivate underground, waiting until the weather gets cool and damp enough for them to emerge from burrows and forage on insects and small vertebrates.

One of the students had her heart set on seeing horned lizards, and her wish came true. Some UCSC interns working on the horned lizard mapping project caught a couple of small lizards for us to see. The larger adults aren't coming aboveground yet.

Horned lizard (Phrynosoma blainvillii) at Fort Ord Natural Reserve
2020-03-06
© Allison J. Gong

Like the tiger salamanders, the horned lizards face an uncertain future of their own. Their main prey are native ants. California has been invaded by Argentine ants--those are the little black ants that get into houses. The Argentine ants are extremely competitive and form supercolonies, wherein two or more adjacent colonies will merge underground and function as a single colony with multiple queens. They can and do outcompete the native ant species, and predators don't seem to like them. Unfortunately, the horned lizards don't eat the Argentine ants. If the lizards' food source is threatened by the ants, then the lizards could be in big trouble.

One of the things Joe wanted to show us was a plant with a tiny purple flower, that is just now starting to bloom.

Gilia tenuiflora ssp. arenaria at Fort Ord Natural Reserve
2020-03-06
© Allison J. Gong

This little plant, called greater yellowthroat gilia or sand gilia, is a California endemic species, found nowhere else. The State of California lists it as threatened, and the federal government lists it as endangered. It's a pretty plant, growing low to the ground because although it's March, we haven't had any rain for about eight weeks. And this is supposed to be our rainy season. Joe showed us some Gilia plantlets that were grown in greenhouses and had plenty of water, and they were three or four times as tall as the ones we saw in the field.

There is a lot of very interesting work going on at FONR these days, and it's exciting for me to see how many students are involved. Some of my students said they would contact Joe about internship opportunities, and I hope they do so. If I'm teaching Ecology again next spring, we're definitely coming back to Fort Ord, and I think we'll do an overnight camping trip. I'm sure the reserve is a completely different place once the sun goes down!

1

The first field trip of the semester for my Ecology class is always a jaunt up the coast to Rancho del Oso and Waddell Beach. It's a great place to start the practice of observing nature, because we can explore the forest in the morning, have lunch, and then wander along the beach in the afternoon. We really are lucky to have such a wide variety of habitats to study around here, which makes taking students out into the field really fun. My passion and expertise will always belong with the marine invertebrates, but it's good for me to work outside my comfort zone and immerse myself in habitats I don't already know very well. During this year's class trip to Waddell Beach I was struck by some things I had seen before but never paid much heed to. And also one very big thing that caught everybody's attention.

Depending on how much rain has fallen recently, Waddell Creek may or may not flow all the way into the ocean. Since California has a short rainy season, there are months when the creek is completely cut off from the ocean, due to both a lack of flow and the accumulation of sand on the beach. So far this rainy season, which began on 1 October 2019, we've gotten about 93% of our normal rain. However, we had a very wet December, and almost no rain since then. I wasn't sure whether or not Waddell would be flowing into the ocean. It was.

Waddell Creek where it flows across the beach into the Pacific Ocean
Waddell Creek flowing into the Pacific Ocean
2020-01-31
© Allison J. Gong

The really big thing that we all stopped to look at was this guy lounging in the creek.

Subadult male elephant seal (Mirounga angustirostris) lying in the creek at Waddell Beach.
Northern elephant seal (Mirounga angustirostris) on Waddell Beach
2020-01-31
© Allison J. Gong

The students had many questions: What was he doing there? Was he sick? Was it a male? Was he dead? Well, no, he wasn't dead. And while I guessed from this view that it was a subadult male, I was secretly relieved to be proved right when we walked down the creek (keeping the mandated distance away from him) and looked back to see his big schnozz.

The elephant seal breeding season is coming to an end, but animals will continue to haul out and rest on the beach. This subadult male clearly isn't going to be dethroning any beachmasters this year, so he has taken the safe route and chosen a beach away from the breeding ground at Año Nuevo, which is ~2 miles up the coast. What I really liked about this particular animal was that we could see the tracks he made getting himself up the beach to the creek.

So that was the big thing. Eye-catching he certainly was, but to my mind not nearly as interesting as the small things we paid more attention to on the beach. It is tempting to think of sandy beaches as relatively lifeless places, compared to something like a rocky intertidal or a redwood forest. But for some reason, this trip I became intrigued by the dune vegetation. At first glance a sand dune seems to be a very inhospitable place for plants, and it is. Sand is unstable and moves around all the time, making it difficult for roots to hang on. Sand also doesn't hold water, so dune vegetation must be able to withstand very dry conditions. It's not surprising that dune plants have some of the same adaptations as desert plants.

Let's start with the natives.

Photograph of yellow sand verbena (Abronia latifolia) at Waddell Beach.
Yellow sand verbena (Abronia latifolia)
2020-01-31
© Allison J. Gong

I love this little sand verbena (Abronia latifolia)! It is native to the west coast of North America, from Santa Barbara County to the Canadian border. It is a sand stabilizer, decreasing the erosion that occurs. The sand verbenas also live in deserts; I saw them at Anza-Borrego and Joshua Tree last year. The beach sand verbena grows low to the ground, probably as a way to shelter from the winds that come screaming down the coast. Cute little plant, isn't it?

The other yellow beach plant we saw was the beach suncup (Camissoniopsis cheiranthifolia), a member of the primrose family.

Photograph of the beach suncup (Camissoniopsis cheiranthifolia) at Waddell Beach.
Beach suncup (Camissoniopsis cheiranthifolia)
2020-01-31
© Allison J. Gong

Like the yellow sand verbena, the beach suncup is a California native. It grows along the entire coast, including the Channel Islands. Also like the yellow sand verbena, the suncup grows low to the ground. Its leaves are thick and a little waxy, to help the plant resist desiccation.

And now for the non-natives. I must admit, I had given very little thought to the plant life on my local beaches. I'd seen and studied beach wrack, but to be honest most of my attention is usually directed towards the water instead of up high on the beach where the plants live. This day I decided to photograph the plants.

This plant is a little succulent called European sea rocket (Cakile maritma). As the common name implies, its native habitat is dunes in Europe, northern Africa, and western Asia.

Photograph of the succulent plant, European sea rocket (Cakile maritima) at Waddell Beach.
European sea rocket (Cakile maritima) at Waddell Beach
2020-01-31
© Allison J. Gong

Cakile maritima has several life history traits that enable it to be carried around the world. It produces a lot of seeds, more so than the native dune plants. The seeds are dispersed by water and can be transported long distances in the ballast water of ships, which is probably how it got to California in the first place. It tolerates disturbances better than native dune vegetation, which allows it to be a superior competitor. Cakile maritima is considered to be invasive, meaning that it can survive and spread on its own in a non-native habitat, but its effects seem to be restricted to beach dunes. Despite its ability to thrive and outcompete our native beach plants, it appears to be unable to expand away from the sand.

Mushrrom, Psathyrella ammophila, growing out of the sand at Waddell Beach.
Psathyrella ammophila at Waddell Beach
2020-01-31
© Allison J. Gong

Our surprise of the day was a beach mushroom! None of us had seen them before. This is Psathyrella ammophila, the beach brittlestem mushroom. Like sea rocket, it is also a European invasive. We were perplexed by this mushroom. Most of a fungus's body (mycelium) is underground. The mycelium spreads through soils as very thin threads called hyphae. Every once in a while the mycelium sends up a fruiting body, which is what we call a mushroom. There is no way to know, from the location of mushrooms, where and how far the mycelium spreads underground.

The presence of a mushroom on the beach means that a fungal mycelium is feeding on something in the sand. There isn't much plant matter buried on beaches, but we hypothesized that perhaps one of the logs from the forest had washed down the creek and been deposited on the beach. It would then be buried in sand, along with all the mycelium it carried, and a mushroom could have sprouted up through the sand.

Well, it was a good hypothesis.

I posted my photo to a mushroom ID page, and it was identified as Psathyrella ammophila. My submission to iNaturalist came back with the same result. A little research led me to another non-native invasive species, Ammophila arenaria, the European marram grass. Notice that the species epithet of the mushroom is the same as the genus name of the plant? That was my first clue. Marram grass is one of the most noxious weed species on the California coast. It was intentionally introduced to the beaches in the mid-1800s, to provide stability to the dunes. It is very good at that, but also spreads very rapidly, usually growing upwards away from the ocean. That said, marram grass also breaks off chunks that can survive in the ocean and float off to colonize new beaches.

The fungus Psathyrella ammophila grows as a saprobe on the decaying roots of Ammophila arenaria. No doubt the fungus was introduced along with the marram grass as an inadvertent hitchhiker. Since there is so much marram grass on our beaches, it's safe to assume that there is a lot of Psathyrella, too. That means it's time to start looking for mushrooms on the beach!

A while back now I went out on a low tide even though the actual low was after sunset. I figured that it was low enough that I'd have plenty of time to poke around as the tide was receding. And given that there were promising clouds in the sky, I took my good camera along just in case the sunset proved to be photo-worthy. Having had enough of crowds in the intertidal at Natural Bridges the previous day, I decided to venture up to Pistachio Beach, which isn't as heavily visited.

I ended up spending only 45 minutes in the intertidal, all the while watching the sun sink lower in the sky. It was already too dark to take many photos in the tidepools, but there were some interesting things on the beach.

The majority of shells that wash up on any beach are going to be molluscs, usually either gastropods or bivalves. I've often seen living red abalone (Haliotis rufescens) hidden in nooks and crannies at this site, so it's not surprising to find their shells on the sand. Usually, though, the shells are a little beat up. This one was intact, with a lovely layer of nacre inside.

This butterfly-shaped object is one of the shell plates of Cryptochiton stelleri, also known as the gumboot chiton. Cryptochiton is the largest of all chiton species; the largest one I've ever seen is the length of my forearm from elbow to fingertip. Like all chitons, C. stelleri has a row of eight shell plates running down the dorsal side of the body. Unlike other chitons, however, in Cryptochiton the plates are covered by a layer of tissue called the girdle and not visible from the outside. If you run your finger down the back you can feel the plates under the girdle. I never thought about it before now, but it seems that the name Cryptochiton refers to the hidden chiton-ness of the animal.

Anyway, Cryptochiton lives mostly in the subtidal, although you can occasionally see them in the very low intertidal. As subtidal creatures they have neither the ability nor the need to cling tightly to rocks, as their intertidal cousins do. This means that when big swells come through at low tide, they can get dislodged and wash ashore. I know from personal experience that the tissue of Cryptochiton is really tough. Once a pal and I were trudging back after working on a low tide and came across several dead Crytochiton scattered over the beach. We decided to do an impromptu dissection and try to salvage the plates, hacking away with her pocket knife. The smell was horrendous, and after several minutes we made practically zero progress, so we gave up. I've seen gulls pecking at dead Cryptochiton, too, and they didn't seem to have any success either. However, their bodies do eventually disintegrate, or something manages to eat them, and their naked plates can often be found on beaches.

Shell plate of Cryptochiton stelleri
2020-01-12
© Allison J. Gong

One of the coolest pattern I've ever seen in the intertidal was this:

Leaf barnacle (Pollicipes polymerus), mussels (Mytilus californianus), and limpets (Lottia sp.)
2020-01-12
© Allison J. Gong

I've never seen anything like this before. It's hard to tell from the photo, but these two rock faces converge into the crevice, sort of like the adjacent pages in an open book. This side of the rock surface faces away from the ocean and will never be subject to the main force of pounding waves. The barnacle in the middle is attached pretty much in the deepest part of the crevice, and is surrounded by mussels, which are then surrounded by limpets.

Now, all of these animals recruited to this location after spending some period of time, from a few days to a few weeks, in the plankton. The barnacle certainly can't move once it has settled and metamorphosed. Newly settled mussels have a limited ability to scoot around a bit but are generally stationary once they've extruded their byssal threads and fastened them to something hard. The limpets, on the other hand, are quite mobile. The barnacle and mussels gave up their ability to move around after they became benthic, but limpets can and do locomote quite a bit--in fact, they have to, in order to feed. So in a sense, these limpets "chose" to aggregate together long after settlement.

What are the ecological implications of this pattern?

Well, for one thing, that barnacle is a genetic dead end. I've written before about the bizarre sex lives of barnacles. This one lone barnacle, far from any others of its species, is not able to reproduce. It has nobody to copulate with. It is possible that other barnacles will recruit to the mussels (Pollicipes is often associated with Mytilus), but until then there will be no sexy times for this individual.

Another ecological consequence concerns the limpets. If these are owl limpets (Lottia gigantea), then some of them will grow up to be the big females that maintain farms on the rocks where they manage and harvest the crop of algal film that grows. These big females are territorial, and will bump or scrape off any creature found to be trespassing on their farms. Clearly, none of the limpets in the photo above are demonstrating any type of territorial behavior! So they are either some other species of Lottia, or are younger individuals of L. gigantea that haven't yet made the change from male to female.

In any case, I do think the pattern is very interesting, even though I don't understand it. Or maybe because I don't understand it. I'm always intrigued by something that I can't explain, which is a good thing because it means I don't get bored very often. If anyone reading this has an explanation for this pattern, let me know about it!

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