Observations of Flowering Plants and the Main Vernal Pools on the Mesa de Colorado, 3/18/01 to 4/14/01

Chronological Observations

Introduction to this page

Observations 2000 November 4 - 2001 February 23
Observations 2001 February 26 - 2001 March 16
2001 March 18
2001 March 20
2001 March 23
2001 March 24
2001 March 27
2001 March 30
2001 April 1
2001 April 4
2001 April 8
2001 April 11
2001 April 14
Observations after 2001 April 14

2001 March 18 (Day 33): Vernal Pool Trail. It was a beautiful warm and sunny day! The plants are bursting into bloom, and tadpoles and garter snakes have appeared in the Pond for the first day. The pleasant weather is rapidly bringing us into Spring.

I spent five hours docenting at the Pool. A steady stream of people came at nearly a uniform rate the entire afternoon.

The snakes were clearly the hit of the day, not only in the Pool but outside the Pool. Before I even got to the Pool, a lady told me about the large rattlesnake at the Adobes. So beware: the snakes are out!

The tadpoles were about 1/4" long, and came in two varieties: one solid black, and one mottled gray. They were the reason the two-striped garter snakes were there. It is amazing how the first day that the tadpoles were visible and abundant that the snakes appeared as well. It definitely was enjoyable watching the snakes hunt for tadpoles, swimming along with their head out of the water.

The solid black tadpoles definitely outnumbered the gray ones, and had a maximum density of ~2 per square foot. I observed three distinct garter snakes in the water.

Maximum densities: fairy shrimp (1/4-1" long), 5; gray shrimp, 2; red shrimp, 1; new gray shrimp, 5; water boatman, 1-2. I didn't observe any rear-propelled gray shrimp or springtails, but didn't have time to adequately study the Pool for them.

2001 March 20 (Day 35): Vernal Pool Trail, Vista Grande Trail, Waterline Road, Fault Line Road. It was a quite warm day, and the bloom just keeps getting better. Goldfields are present now, but you have to look carefully to distinguish them from blennosperma.

The surface of the Pool is continuing to accumulate algae, as it always does. Perhaps 10% of the entire Pool surface is covered with algae, and the water is getting murkier from algae in the water.

The tadpoles have doubled in size in only two days, and are now 1/2" long, half wriggly tail and half body. Their density has gone up five times, to 10 per square foot for the black ones and 2 per square foot for the gray ones. There was only one snake around feasting on the tadpoles.

I observed only two clusters of western spadefoot toad eggs, but ~40% of the surface of the water near the boardwalk is now covered with algae.

I drove to the Visitor Center and hiked to the burn area. I was stunned to see a field with over 200 chocolate lilies in full bloom, as well as nice patches of shooting stars and blue dicks. Very different from the corner of the burn area I saw four days ago!

2001 March 23 (Day 38): Vernal Pool Trail. Another pleasant day, with the blooms still getting better.

The small pools have changed noticeably. Much more green covers the edges, and a few small areas of gold ring the pool farther from the Vernal Pool Trailhead.

Dragonflies again escorted me to the Pool, this time without the clouds of male mosquitoes. I gave a tour of the Pool to ~25 people in my ~1 hour there, and in turn one of them found a dragonfly larvae, eating something that look suspiciously like a fairy shrimp remnant. Otherwise, the Pool and its inhabitants were much the same as three days ago.

2001 March 24 (Day 39): Vernal Pool Trail. Another pleasant day, although a bit on the cool side. I docented at the Pool in the afternoon.

This was a very instructive day! Al and Mary Pentis of the Vernal Pool Society visited the Pool just before I got there, and Kay Madore got to observe the fairy shrimp out of the pool. I talked to Al and Mary on my way to the Pool, and Kay told me what she had learned from them at the Pool.

The most stunning thing was that what I had thought was a female with two egg sacs turns out to be a male with two gonads! Realizing that it was a male then made it very easy to see his long clasper antennae at the front. They are longer than the legs, and remain relatively stationary while the legs beat furiously back and forth.

Al and Mary said that the claims that the males died within an hour of copulation were incorrect for the shrimp they have observed in California.

These two new facts then resolve the questions I had about reconciling that "females can mate multiple times" with "males die within an hour after copulation". If the males continue to live, then there is a chance for multiple matings. I also couldn't understand why only 10% of the females had full egg sacs if the males had already finished copulating.

Al and Mary verified that my so-called "red shrimp" are in fact Cyclops, as I had suspected from its general appearance. They said they observed Daphnea (waterflea) and Ostracodae today. They took pictures of our Pool inhabitants, which I will try to obtain for the Introduction to the Main Pool Inhabitants page here.

Al and Mary said that the black tadpoles were Pacific Treefrogs, and the gray tadpoles were western spadefoot toads. I'll try to confirm this as they evolve, since I am definitely confused about resolving their observed characteristics with published descriptions of these species.

Today was beetle mating day. At least two different pairs of beetles were vigorously mating, rolling around in the water, and literally coming up for a breath of air every 20 seconds or so!

Several two-striped garter snakes were cruising for tadpoles again.

The fog started to roll in about 5 pm, which produced patches of fog as the breeze hit the tops of waves in the Pool that then blew across the Pool. Thus as one was looking at the fairy shrimp, puffs of fog would roll across one's viewpoint every half second or so. On the way back to the Vernal Pool Trailhead, the fog made it extremely easy to see where the drainage basins were. The ridges clearly stood out across the fog background beyond. In particular, I could clearly see where the area just north of the small pool next to the Trailhead drained into the intersection of Los Gatos and Avocado Mesa Roads. This was the first time I had noticed that one could see the street sign at that corner from the Vernal Pool Trail in one place.

2001 March 27 (Day 42): Vernal Pool Trail, Multiuse Trail. A stunning day in three ways, only one of which I expected.

First, at the Pool every single member of the large species of fairy shrimp (1/2 - 1" long) has vanished! This should not have been unexpected by me, since my observations last year showed that they had vanished between day 30 and day 40. But it was completely unexpected by me, since I had thought that the numbers would gradually decline over a period of a week or two before they vanished. For example, previous reports of the lifetime of the Riverside fairy shrimp (which is probably what this species is), have said 48-56 days, which would give a gradual decline in numbers over 8 days. Such a distribution is quite common in nature, due to genetic and environmental variation.

This means that the large species of fairy shrimp completely died out over an interval of less than three days! On day 39, there was no evidence of a decline in their population at all, and the population showed a range in the size of the egg sacs. How in the world did they all get the message to die simultaneously??? Is it possible that these shrimp are all virtually genetically identical, and that the environmental variation is so small that they could all die within a three day interval?

Alternatively, if the garter snakes eat shrimp, that they could cause a large decrease in population. However, I would expect that it would be nearly impossible for the snakes to eat the entire population, without a few survivors, in such a short period. (It becomes harder and harder for the snakes to locate and eat their prey as their numbers dwindle.) And I have not heard of the snakes eating the shrimp.

Kay Madore was at the Pool late Sunday and saw only a few of the larger shrimp, hardly any with eggs, implying that the shrimp died over an interval of only a day. If anyone was at the Pool on Sunday, March 25 or Monday, March 26, and could reliably identify the presence or absence of the 1" length shrimp, this could help pin down the interval even more. Please email me with your observations!

The second stunning event was hiking through hundreds of acres of hoaryleaf ceanothus in its fragrant, heavenly, full bloom. The northern hillsides of the Reserve are carpeted with large bushes with billowing mounds of white blooms. This is one of the most impressive years recently, perhaps due to a compressed bloom period brought on by the very cold winter. There are no stragglers in this population either; every bush is in full bloom.

I had expected that I would find the hoaryleaf in full bloom, and I was deeply grateful that my expectations were fulfilled. Nearly every foot of the Multiuse Trail from just north of the trailhead off Clinton Keith Road either has hoaryleaf lining the trail, or views of hundreds of acres in bloom surrounding the trail. See the pictures for a small sample of the treats along this trail now.

Jane Strong and I have long wondered why descriptions of hoaryleaf ceanothus don't mention the very strong delightful scent that perfumes the air for quite a distance from the plants. Jane finally realized why on this trip; many botanists must work with the dried pressed specimen in herbaria, whose scent is long gone, and mostly observe the plant the 90% of the time it is not in bloom.

The third stunning event was back at the Pool. Due to my surprise at the complete absence of the largest fairy shrimp, I went back at dusk to see if maybe they had all been visiting the other end of the Pool away from the boardwalk. The absence was confirmed; a visual search, aided by flashlight, still revealed no large fairy shrimp. But I found something else unexpected: 20% of the remaining population of fairy shrimp (Linderiella occidentalis with red eyes) were mating!

The mating behavior was not obvious at first. I first noticed that the females with egg sacs seemed to have an additional pair of antennae with red balls just below their legs. (I didn't know at the time that these were red compound eyes on eye stalks.) After further study, I finally noticed the additional set of legs below those of the female!

This mating had probably been going on all day, but I had missed it before. Earlier in the day, Jane and I had noticed this large cluster of fairy shrimp (~40 in a square foot, compared to the usual highest number of ~10 in a square foot) next to the boardwalk in one specific location. In retrospect, this was very unusual to find so many fairy shrimp in one location. The mating is thus now occurring in large groups of fairy shrimp, instead of in one-on-one encounters in the field.

It was also surprising that the only females that were mating were ones with what looked like fully developed egg sacs with eggs in them.

What a day!

2001 March 30 (Day 45): Vernal Pool Trail, Multiuse Trail. A sunny and pleasant day.

The two small pools have become mostly green, and the Main Pool has green plants covering some of its farthest extent. Algae is covering about 20% of the Main Pool, including about 50% near the boardwalk, continuing its relentless extension over the entire Pool.

The Santa Rosa fairy shrimp (the ones with red eyes) are still mating in the same spot next to the boardwalk. Again, the mating occurs only for females with full egg sacs. Very curious!

One group of people had told me that they had seen a turtle in the Pool, about 1" long. Despite a number of eyes at the Pool looking for a turtle, none were found. However, when my son Matthew found a pair of predaceous diving beetles mating upside down, it immediately became clear to me that this is what that group saw. Indeed, from upside down, the red shell-like bottom of this beetle, and the legs with what looked like sheaths around them, could be easily mistaken for a small turtle.

2001 April 1 (Day 47): Vernal Pool Trail. A foggy and cold day. I docented at the Pool from 2-6 pm.

The blooms were nearly all closed up due to the fairy heavy fog, disappointing the large number of people who showed up because it was warm and sunny in the Murrieta - Temecula area.

The Pool continues to surprise me - the tadpoles were nearly all gone. However, unlike the complete demise of the large fairy shrimp, there were still a few around, but you had to hunt for them. Having at least some survivors is what I expected for a population being consumed at a high rate by the snakes. Both black and gray tadpoles were still present, but their densities were reduced by much more than a factor of 10 from two days ago.

The fairy shrimp were found exclusively in a single stretch between two posts of the boardwalk, the same location of the large cluster seen in the last five days. Again, ~10% of them were mating, and nearly every person I tutored was able to find a mating pair of shrimp.

It thus is now fairly clear that the remaining fairy shrimp will be gone soon, since the population is very much smaller that what it was previously. However, the other denizens of the Pool were essentially unchanged in numbers over the past two weeks, so the demise of the fairy shrimp and tadpoles are specific to those species.

All the pools are becoming increasingly covered with algae, grasses, rushes and the clover fern. The small pools are mostly green in appearance from afar, whereas the Main Pool has only a minor covering of green. About 15% of the entire Pool is covered with algae, but the algae is concentrated near the boardwalk, perhaps due to the prevailing winds. About 50% of the area near the boardwalk is covered with algae. The water itself is quite murky, making it difficult to see the very bottom of the Pool clearly.

2001 April 4 (Day 50): Vernal Pool Trail, Trans Preserve Trail, Los Santos Trail. Another cold and cloudy day.

Flowers, flowers everywhere! Although some of the flowers were muted by the cloudy weather, it is difficult to look around and not find patches of color due to showy flowers. There are yellow patches of blennosperma and goldfields, including a river of goldfields along the drainage of the Mesa de Colorado leading to the corner of Los Gatos and Avocado Mesa. There are pink patches of ground pinks sprinkled around the Vernal Pool Trail. There are fields of shooting stars nearly everywhere you look on nearly the whole Reserve. The grasslands also have johnny-jump-ups, California buttercups and blue dicks sprinkled lavishly throughout.

Pictures don't do the flowers justice, however, since the green grasses dominate pictures. Somehow, one's eyes ignore the predominant green, and exquisitely pick out the color sprinkled amidst the green.

The two small pools look nearly green with spike rush, and as if their water is gone. This is deceiving, however, since they undoubtedly still contain a lot of water. The same phenomenon can be viewed up close at the Main Pool, which has a few edges that similarly appear solid green from a distance, but clearly contain water when viewed up close.

The fairy shrimp are nearly gone. I counted only five separate shrimp total in the ~one hour I spent at the Pool. Thus the Pool is following virtually to the day the same script as last year for the disappearance of the two species of fairy shrimp.

The red cyclops are now the dominant creature in the Pool, but they still have no sign of egg sacs. The poor tadpoles are extremely hard to find. They seem to be hiding in the algae, which is quite understandable. After all, for 17 days, the two-striped garter snakes have been pursuing and eating perhaps 99% of them. The tadpoles are probably quaking in fear as they hide in the algae - wouldn't you??!

One of the unknown species now has a clear shell around it, with a small opening in the front, and can be identified as a ostracod, or seed shrimp. It does indeed look like a plant seed that zips around in the Pool.

Chocolate lilies are now in full bloom on the sides of the Mesa de Colarado, with over several hundred blooming along each of the Vernal Pool, Trans Preserve and Los Santos Trails.

I heard a very curious sound while I was at the Adobes - the clear bark of a dog alerted by some intruder. This was extremely surprising, since I had never heard a dog in the Reserve. (They aren't permitted in the Reserve, and I've never seen one in it.) I was fortunate to find out soon afterward what happened, thanks to my docent uniform, when the people being barked at asked me about their experience.

Four people, two Fallbrookers and two people visiting from Cincinnati, were walking on the Adobe Loop Trail when a coyote started barking on them. (That's the sound I heard.) The coyote then followed it up with typical coyote howling. (The Fallbrookers were of course intimately familiar with the sounds of coyotes, since we hear them almost nightly in Fallbrook.) We speculated that the people were walking very close to the den of the coyote, which was populated by baby coyotes, and that the mother was trying to draw the people's attention toward her and away from her den. If anyone can think of any other reason, please email me!

2001 April 8 (Day 54): Vernal Pool Trail, Waterline Road, Vista Grande Trail, Faultline Road, Monument Hill Road. Another cold day, but only partly cloudy this time.

The tadpoles are back! I don't know why, or where they came from, but the biggest tadpoles now have a maximum density of ~6 per square foot, much much higher than in the last week. Were they all hiding on the other side of the Pool from the garter snakes near the boardwalk? These tadpoles are clearly the same first hatch of tadpoles, since their main bodies are now ~5/8" long, with a somewhat shorter tail. They are so big that they can now be found simply by looking for ripples on the surface of the water.

Surprising, the tadpoles are now mostly all gray, with only a few black ones. Have the black ones mostly turned gray?? Their eyes are clearly visible now as being on the side of the top of their heads. The large tadpoles are accompanied by a new crop of very small tadpoles, with main bodies ~1/4" in length.

Kay and I observed ~five fairy shrimp still hanging in there, although one appeared quite senescent, nearly sticking its unusual bluish-colored tail out of the water as it flopped face down. The Cyclops still show no sign of eggs. The ostracods number about 10 per square foot, swimming steadily along.

Spike rush now appears to cover most of the small pools, and ~15% of the Main Pool. It has grown quite a bit in length in the past four days, nearly obscuring a rock that was totally unobscured four days ago.

The burn area is now nearly a solid blue-purple sheet of color. Within the drainages of the burn area, California buttercups and the pitted onion produce rivers of yellow and white.

Amazingly, there are only ~ten aged chocolate lilies left where there were over 200 a few weeks ago. No dead flowers and no stalks with seeds are present, as if something has eaten the flowers and stalks. (The chocolate lilies are still in full bloom along the edges of the Mesa de Colorado, which bloomed later than those in the burn area.)

At the Vernal Pool Trail, the ground pinks still were mostly closed, even when the sun peeked out behind the clouds, at 9:30, noon, and 4:30 pm. Do they close because of cold as well as clouds?

2001 April 11 (Day 57): Vernal Pool Trail, Punta Mesa Trail, Faultline Road, Waterline Road, Tenaja Road, Oak Tree Trail, Coyote Trail, Hidden Valley Road, Los Santos Trail. Another cold and cloudy day, made worse by drizzle near the end.

And the tadpoles are mostly gone again.... I only saw three tadpoles in a half-hour at the Pool. It was so cold today (54° at 2:30 pm) that even the seed shrimp (ostracods) were mostly frozen in place in the algae, looking very much like seeds on the algae. But the few fairy shrimp are hanging in there. I observed only two of them, looking very senescent. They were sluggish, hardly moving in the water instead of their usual vigorous swimming. (This was not due to the cold, since they swam vigorously at such temperatures in the past.) They couldn't even keep themselves horizontal, with their tails dropping lower.

I observed a several inch diameter spherical ball of very small gray organisms, each less than 1/32", that I had never seen before. There were also lots of baby Cyclops in the Pool today.

Unfortunately, I observed further evidence of vandalism to rocks on slopes. At the point where the Vernal Pool trail drops off the Mesa de Colorado, a rock on the right side of the trail has been removed, leaving a gash in the earth where it used to be. It is hard for me to imagine that the little pleasure miscreants get from rolling rocks downhill is worth their efforts. (In this case, I didn't see the rock farther downhill, so I suppose it is also possible that someone coveted this particular rock and carried it out.)

The chocolate lilies along the Vernal Pool trail are ending their show. This coming weekend will probably be the last one to provide much of a display.

The show of shooting stars along the Punta Mesa trail is completely over, with large seedpods instead of flowers. The hoaryleaf ceanothus there is near the end of its bloom, with many flowers fallen and the rest a dull white color. The Ramona lilacs are in lovely full bloom, but there are so few of them that they don't make much of a display.

However, I was pleasantly surprised by the display of California poppies along the last half of the trail. This may be the best display of poppies on the Reserve. And I was following deer tracks for some distance along the trail!

The burn area is still resplendent with blue dicks, and the river of white and gold in the drainage along Faultline Road is an amazing sight.

Shooting stars are still providing a good show along the Coyote Trail, where I caught a bicyclist riding on it despite clear signage against it. In six years of hiking the SRP, I've only seen two bicycle tracks, and both times I've seen the bicyclists. I talked to the first one, as a fellow mountain bicyclist, about how such violations could lead to the banning of bicycles in the rest of the SRP, but the second one ran from my ranger shirt preventing me from talking to him. I got his license number and reported him to the Ranger.

Fortunately, it is indeed impressive how good the compliance is with bicyclists staying out of restricted areas. It is easy to measure the compliance since bicycle tracks stay around for a long time as evidence of any violation.

2001 April 14 (Day 60): Vernal Pool Trail, Multiuse Trail. A pleasant day for a change - sunny, with a high temperature around 70°. It was the first time in a long time that I've seen the ground pinks open on the Vernal Pool Trail, and they are making a good show.

However, I sense that we are just past the peak of the overall bloom, at least as measured by the most spectacular displays. The hoaryleaf ceanothus bloom is over everywhere. The hundreds of acres of bright white have become a dull white. Some individual plants still look pretty good, but the fabulous fragrance is gone. Similarly, the beautiful sugarbush bloom of the last several weeks has muted. The chocolate lilies ended a week or two ago in the burn area, and will soon end elsewhere. Most of the fabulous shooting star displays in the grasslands are over. The johnny-jump-ups are beginning to show faded flowers that aren't being replaced as fast as they finish.

But as some blooms go, others appear. The prodigious Chaparral Yucca bloom stalks have flowers on their bottom portions. Red berries have appeared on the mission manzanita, producing a better show than their flowers did this year. Most species are in fact either just beginning to bloom or still approaching their peak bloom. Many are quite lovely flowers, such as owl's clover, but they just don't produce massive displays like the ones that are ending.

Being just past the peak of the overall bloom of course means that the bloom is still essentially at its peak. And visitors have responded to that peak dramatically! Rick Bramhall, at the Visitor Center today, reported that he had not seen so many visitors since the last El Ninño year. Over 1,000 people visited the Santa Rosa Plateau on Saturday.

Another powerful force brought visitors to the Santa Rosa Plateau: it has one of the best blooms around. For three weeks in a row, it has been featured on the Theodore Payne Foundation Wildflower Hotline as one of the places with the best blooms in Southern California. Most other areas are behind due to the cold weather. For example, very few poppies were in bloom in Lancaster for the Poppy Festival a few weeks ago at the Antelope Valley California Poppy Preserve - the Santa Rosa Plateau had many more poppies in bloom then!

The small pools are virtually all seas of green, and the Main Pool is rapidly turning green with spike rush. Mats of algae are prominent next to most of the boardwalk, giving the tadpoles even more cover to hide from the snakes.

The largest tadpoles from previous days seem to have been eaten, since the largest tadpoles today are slightly smaller now than previously. It doesn't seem to pay off to be the earliest tadpole to hatch!

When I got back to my car at sunset, one other car remained. I always wonder about the last car at the trailhead. Did something go wrong? Is there someone on the trail who needs help? Or is it simply a hiker like myself, who tallied a bit too long looking at something or who decided to try to do as long a loop as possible before dark. (In most cases, that last car is mine!)

In this case, I got to find out. As I was driving from the Vernal Pool trailhead to I-15, I saw two people walking alongside the road, looking much out of place. I stopped and asked if that "last car" was theirs. It was. They told me they had taken a wrong turn, and then weren't sure how to get back to their car. They were ever so grateful to get a ride back to their car.

By the way, this is not terribly unusual. Regularly, but infrequently, I get people asking me where they are, and how do they get back to their car. At the end of their shifts, volunteers sometimes end up giving rides to people who can't hike back to their cars!

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Copyright © 2000-2001 by Tom Chester.
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Updated 7 August 2001.