As I write these words, a massive and powerful wildfire is raging through the Santa Cruz Mountains, approaching the city of Santa Cruz from the north and west. This morning's stats:
63,000 acres burnt/burning
1157 people fighting the fire (roughly 10% of what is needed to fight a fire of this size)
firebreaks constructed to protect the city and university
firefighters coming from out of the area and out of state
Much of the terrain burning is redwood forest. Big Basin Redwood State Park has burnt extensively. All park buildings and campgrounds have been severely damaged if not destroyed. Up the coast from me at Waddell Creek, the fire burned all the way to the ocean. Rancho del Oso, the nature center at the bottom of Big Basin at Waddell Creek, is in the middle of the forest; I don't know whether or not it still stands.
Each of these leaves tells the story of the destructive power of Nature. Most of them are from tanoak trees (Neolithocarpus densiflorus) or California bay laurel (Umbellularia californica), both of which are very common understory trees in redwood forests. For the past week, charred leaves have been tossed by updraft and carried along the wind, to be deposited miles away. Fortunately they are no longer acting as live embers when they touch down.
My camera gear is all packed up, in case we need to evacuate. I took these photos with my phone when I went to the marine lab this morning. They are completely unaltered. If they look a little too orange, well, that's how everything looks right now.
Why did I feel compelled to take these pictures? I think it's because the damage to Nature caused by Nature should be acknowledged as well as the damage to human lives, homes, and health. What I'm about to say may sound insensitive. I do not want to diminish the human tragedy of lost homes, livelihoods, and health. But I do want to shift my personal focus a little bit, because dwelling on all that has been and could be lost only renders me unable to function. If I can think about the future, perhaps even the long-term future far beyond my own life, I feel more grounded and ready to deal with the now.
What is and has been happening to the redwood forests is absolutely tragic. But the redwoods themselves are fire-adapted and resilient. The forest will recover. Already there are Facebook groups organizing to help the residents who have been displaced, begin the long and arduous process of cleaning up once the fire crews give the okay to do so, and start thinking about long-term monitoring of the forest's recovery. From a purely ecological perspective, it will be fascinating to document the process of secondary succession.
But before any of that can happen, human safety is the top priority. We are far from the end of this ordeal. While the weather has cooperated the past couple of days, with cooler temperatures and higher humidity thanks to the return of the marine layer, the forecast calls for 20-30% chance of lightning weather Sunday through Tuesday. That means more lightning strikes and more fires starting. We were visited by a firefighter yesterday afternoon, who told us that while we were not in the immediate evacuation zone we need to be ready to go. She advised us to do the usual fire prevention stuff—clear out a defensible space around the house, make sure there's no leaf litter or debris on the roof, etc. So we did. And now we stay indoors as much as possible, as the air quality outside is dismal. And we wait.
On the afternoon of July 31, 2020 the world of invertebrate biology and marine ecology in California lost a giant in our field. Professor Emeritus John S. Pearse died after battling cancer and the aftereffects of a stroke.
John was one of the very first people I met when I came to UC Santa Cruz. Before we moved here, my husband and I came and met with John, who was not my official faculty sponsor but agreed to show us around so we could check out different areas for a place to live. In fact, I had applied to the department to do my graduate work in John's lab, but because he was considering retirement the department wouldn't let him take on a new Ph.D. student. But when we needed some help getting acquainted with Santa Cruz, John and his wife, Vicki Buchsbaum Pearse, graciously let us stay at their house and spent a day driving us around town and showing us eateries as well as potential neighborhoods.
By happenstance we ended up living down the hill from John and Vicki. We had met their blue duck, Lily, and I used to fill spaghetti sauce jars with snails from our tiny yard and trudge up the hill to feed them to her. She gobbled them up like they were her favorite treat.
As one of the regional experts in invertebrate biology, John was on all of my graduate committees. There were always a half-dozen or so of us grad students working with invertebrates, and we all tended to hang out together. John was one of the things we shared in common. And even if he wasn't technically on one's committee, he would always be available for consultation or advice as needed.
When John retired, he didn't leave the campus. He remained a presence at the marine lab, and still did field work. He started incorporating young students in his long-term intertidal monitoring research, which morphed into the LiMPETS project. The combination of working with students while producing robust scientific data was the perfect distillation of John's legacy. He said this about LiMPETS:
This is one of the best things I could ever do to enhance science education and conservation of our spectacular coastline. Working with teachers and their students is a wonderful and fulfilling experience.
John S. Pearse, Professor Emeritus UC Santa Cruz
The last time I saw John was in the summer of 2019, during his annual Critter Count. He started these Critter Counts back in the 1970s, monitoring biota at two intertidal sites in Santa Cruz. These sites have since been incorporated into the LiMPETS program. I'm sure it made John smile whenever he thought of generation after generation of schoolkids traipsing down to the intertidal with their quadrats and transect lines, counting organisms the way he had for so many years.
When I started teaching my Ecology class, John suggested that I take the students out to Davenport Landing to monitor at the LiMPETS site there. That is another of his long-term sites, and he was worried about losing information if it were not sampled at least once a year. My students have done LiMPETS monitoring three years now, and John accompanied us on at least two of those visits. I tried to impress upon the students that having John Pearse himself come out with us was a Big Deal, but am not sure I was able to convince them of how fortunate they were. I bet there are a lot of marine biologists in California who would dearly love to go tidepooling with John. And now no one else will.
John Pearse and Todd Newberry, the other professor who gets the blame for how I think about biology, taught an Intertidal Biology class. I came along on many of the field trips the last year they taught it. I remember getting up before dawn to drive down to Carmel, park in the posh neighborhood streets, and walk down to meet John and Todd in the intertidal. I remember slogging through the sticky mud at Elkhorn Slough, digging for Urechis and hearing John shout "It's a goddamned brachiopod!" from across the flat. I remember bringing phoronid worms back to the lab, looking at them under the scope, and watching blood flow into and out of their tentacles. I remember John taking an undergraduate, Jen, and me out to Franklin Point, and showing me my very first staurozoans. That was probably around 1996, and I'm still in love with those animals.
I'm no John Pearse or Todd Newberry, but I'm a small part of their giant legacy in this part of the world. I strive to instill in my students the joy and intellectual pleasure in studying the natural world that I inherited from John and Todd. Partly to honor them, but mostly because it suits my own inclinations, I'm on a one-woman crusade to bring natural history back into modern science and science education.
I've spent the last two mornings in the intertidal at two of the LiMPETS sites, as part of a personal tribute to John. I thought there would be no greater way to memorialize John than by spending some quality time in the intertidal, where he trained so many young minds. I was thinking of him as I took photos, and thought he would be pleased if I shared them.
Natural Bridges—4 August 2020
And because, like me, John had a special affinity for the anemones:
And he would have loved this. What is going on here? How did this pattern come to be?
And look at this, three species of Anthopleura in one tidepool! Can you identify them?
Davenport Landing—5 August 2020
It was windy and drizzly this morning. I ran into a friend, Rani, and her family out on the flats; they were leaving as I arrived. I hadn't seen her since before the COVID-19 lockdown began back in March. She was also visiting the tidepools to honor John Pearse. We chatted from a distance and exchanged virtual hugs before heading our separate ways.
It felt like a John Pearse kind of morning. I recorded the video clip I needed for class, collected some algae and mussels for a video shoot tomorrow, and took a few photos.
And even though I'm not very good at finding nudibranchs, even I couldn't miss this one. It was almost 4 cm long!
The ultimate prize for any tidepool explorer is always an octopus. When I take newbies into the field that's what they always want to see. I have to explain that while octopuses are undoubtedly there and common, they are very difficult to find. You can't be looking for them, unless you really like being frustrated.
But John must have been with me in spirit this morning, because I found this:
It was just a small one, with the mantle about as long as my thumb. I found it because I spotted something strange poking out from a piece of algae. It was the arm curled with the suckers facing outward. I touched it, and the arm retracted. It didn't seem to like how I tasted.
And lastly, for me this is the epitome of John Pearse's legacy: Working in the intertidal, showing students how to identify owl limpets. I hope they never forget what it was like to learn from the man who with his wife, literally wrote the book about invertebrates and founded LiMPETS.
RIP, John S. Pearse. You left behind some enormous shoes to fill and a legacy that will stretch down through generations. I count myself lucky to have spent time with you in the field and in the lab. While I will miss you sorely, it is my privilege to pass on your lessons. Thank you for all you have taught me.
Biology is a field of science with very few absolutes. For every rule that we teach, there seems to be at least one exception. I imagine this is very frustrating for students who want to know that Something = Something every single time. It certainly is easier to remember a few rules that apply to everything, than to keep track of all the cases when they don't.
Take, for example, the tube feet of sea stars. Among the generalities that we teach are: (1) sea star tube feet are used for locomotion and feeding; and (2) sea star tube feet are used to stick firmly to rocks and to pry open mussel shells. And we can show many examples of stars clinging to vertical and overhanging surfaces.
Sometimes we can even find Pisaster doing both at the same time:
A photo like the one above is merely a snapshot of an event that lasts for hours. What's going on in there? Chances are it's a life-or-lunch battle, with the star trying to pry open the mussel just enough to slide its stomach between the shells while the bivalve is holding its shells clamped shut for dear life.
Each of these behaviors-—sticking to rocks and prying open mussels—is possible because Pisaster ochraceus has suckered tube feet. The tube foot itself has a flattened surface that squishes out a tiny dab of sticky adhesive glue. Together, the tube feet can adhere quite strongly to hard surfaces. I know from experience that it is impossible to pry an ochre star off a rock after it has had a chance to hang on, unless you're willing to damage several dozen tube feet. The tube feet will grow back, but there's no point in causing harm to the animal.
So that's the general story we teach in school. For most students, that's the entire story. However, it's always the exceptions, the deviations from the norm, that are the most interesting.
Not every sea star clings to rocks in the intertidal. There are several species that are equally at home on both rocks and sand. And among the rock-clingers, not all are as strong as Pisaster ochraceus. The ochre star's sucker-shaped tube feet are an example of the relationship between form and function: the tube feet's morphology provides the surface area for adhesion that allows the animal to feed and locomote over hard surfaces.
As you might expect, sea stars that don't cling to rocks and pry open mussels may not have sucker-shaped tube feet. The spiny sand star, Astropecten armatus, has pointed tube feet! It's hard to see exactly what the tube feet look like in the photo, but here's a video:
See how the tube feet on the underside of that arm end in points rather than suckers? If we revisit the notion of form and function, what questions come to mind when you look at the morphology of the tube feet? And given Astropecten's common name and its habitat, can you think of how it can survive and get around without the sticking power of Pisaster's tube feet?
Observation of Astropecten in its natural habitat would show that it spends a lot of time buried in the sand. It somehow has to get below the surface of the sand, where it feeds on olive snails or other animals that live buried there. How can it do that? Would the generalized sea star sucker-shaped tube feet that we teach to students be useful for burrowing? We can also think about it in a more familiar context: If you had to dig a hole in the ground, would you reach for a plunger? Clearly you wouldn't. You'd use a shovel, or a spade.
Astropecten's pointed tube feet are perfect for punching down between sand grains, enabling the star to work its way down into the sand. The sand star has hundreds of tiny spades at its disposal to use for digging. Circular structures shaped like miniature horse hooves wouldn't be very good at this job, nor would pointed tube feet be very good at sticking to rocks. This animal doesn't obey the "rules" of sea star biology, but form and function, as always, go together.
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.
And of course algae are often the dominant inhabitants in the intertidal.
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."
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.
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.
Tecturapalacea 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.
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:
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.
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!
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.
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.
Ooh, maybe this parent has food!
The second parent lands on the nest. . .
. . . and promptly takes off again. . .
. . . leaving the babies alone in the nest again.
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!
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:
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.
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.
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.
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!
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.
Holding a rodent by the scruff of the neck allows the biologist to handle the animal safely and minimizes the probability of getting bitten.
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.
Cute little guy almost fell asleep on a student's arm.
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.
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.
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.
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!
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.
The really big thing that we all stopped to look at was this guy lounging in the creek.
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.
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.
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.
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.
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!
The intertidal sculpins are delightful little fish with lots of personality. They're really fun to watch, if you have the patience to sit still for a while and let them do their thing. A sculpin's best defense is to not be seen, so their first instinct is to freeze where they are. Then, if a perceived threat proves to be truly frightening, they'll scoot off into hiding. They can also change the color of their skin, either to enhance camouflage or communicate with each other.
Around here we have a handful of sculpin species flitting around in our tidepools. Sculpins can be tricky to identify even if you have the fish in hand--many of the meristics (things you count, such as hard spines and soft rays in the dorsal fin, or the number of scales in the lateral line) used to distinguish species actually overlap quite a lot between species. The fishes' ability to change color means that skin coloration isn't a very reliable trait. When I was in grad school there was another student in my department who was studying the intertidal sculpins, and she told me that most of the ones we see commonly are either woolly sculpins (Clinocottus analis) or fluffy sculpins (Oligocottus snyderi). I've developed a sort of gut feeling for the gestalt of these species, but I'm not always 100% certain of my identifications.
Anyway, back to the camouflaged sculpins. The ability to change the color of the skin means that sculpins can match their backgrounds, which comes in very handy when there isn't anything to hide behind. Since the environment is rarely uniformly colored, sculpins tend to have mottled skin. Some can be banded, looking like Oreo cookies. The fish in this photo lives in a pool with a granite bottom. The rock contains large quartz crystals and is colonized by tufty bits of mostly red algae. There is enough wave surge for these fist-sized rocks to get tumbled about, which prevents larger macroalgae from colonizing them.
Other shallow pools higher up in the intertidal at Asilomar have a different type of rocky bottom. The rocks lining the bottom of these pools are whitish pebbles that are small enough to be tossed up higher onto the beach. I don't know whether or not these pebbles have the same mineral content as the larger rocks lower in the intertidal, but they do have quartz crystals. The pebbles are white. So, as you may have guessed, are the sculpins!
Other intertidal locations have different color schemes. On the reef to the south of Davenport Landing Beach, you will see a lot of coralline algae. Some pools are overwhelmingly pink because of these algae. Bossiella sp. is a common coralline alga at this location.
What color do you think the sculpins are in these pools?
Give yourself a congratulatory pat on the back if you said "pink"!
Sculpins aren't the only animals to blend in with coralline algae. Some crustaceans are remarkably adept at hiding in plain sight by merging into the background. Unlike the various decorator crabs, which tuck bits and pieces of the environment onto their exoskeletons, isopods hide by matching color.
Turning over algae and finding hidden creatures like these is always fun. For example, I saw these isopods at Pescadero this past summer. See how beautifully camouflaged they are?
Sometimes, when you're not looking for anything in particular, you end up finding something really cool. Last weekend I met up with students in the Cabrillo College Natural History Club for a tidepool excursion up at Pigeon Point. We were south of the point at Whaler's Cove, where a staircase makes for comparatively easy access to the intertidal.
It's fun taking students to the intertidal because I enjoy helping them develop search images for things they've never seen before. There really is so much to see, and most of it goes unnoticed by the casual visitor. Often we are reminded to "reach for the stars," when it is equally important to examine what's going on at the level of your feet. That's the only way you can see things like this chiton:
Mopalia muscosa is one of my favorite chitons. It is pretty common up and down the California coast. However, like most chitons it is not very conspicuous--it tends to be encrusted with algae! This individual is exuberantly covered with coralline and other red algae and has itself become a (slowly) walking bit of intertidal habitat. It is not unusual to see small snails, crustaceans, and worms living among the foliage carried around by a chiton. Other species can carry around some algae, but M. muscosa seems to be the most highly decorated chiton around here. I showed this one to some of the students, who then proceeded to find several others. A search image is a great thing to carry around!
Compared to the rocky intertidal, a sandy habitat can be a difficult place to live. Sand is inherently unstable, getting sloshed to and fro with the tides. Because of this instability there is nothing for holdfasts to grab, so there are many fewer algae for animals to eat and hide in. Most of the life at a sandy beach occurs below the surface of the sand, and is thus invisible to anyone who doesn't want to dig. There's a beach at Whaler's Cove where I've found burrowing olive snails (Olivella biplicata) plowing along just below the surface. I wanted to show them to the students, so I waded in and rooted around. I did find Olivella, but I also found a burrowing shrimp. I think it's a species of Crangon.
Now that is some damn fine camouflage! If the shrimp didn't cast its own shadow, it would be invisible. Even so, it was clearly uneasy sitting on the surface like that. I had only a few seconds to shove the camera in the water and snap a quick photo before the shrimp wriggled its way beneath the sand again.
As I've said before, observation takes practice and patience. To look at something doesn't mean you truly see it. That's why it is so important to slow down and let your attention progress at the pace of the phenomenon you're observing. If the only things that catch your eye are the ones that flit about, then I can guarantee you will never find a chiton in the intertidal. And wouldn't that be a sad thing?