Trail Reports, Santa Rosa Plateau, 2004-2005

21 October 2004
30 December 2004
2 February 2005

21 October 2004: Vernal Pool Trail (see Vernal Pool Trail Plant Guide)

Yesterday, I suspected that the downpour of rain we received in the last four days might have resulted in the formation of the vernal pools, so I sent out an email to friends asking for any observations. Zach Principe drove by the Vernal Pool Trailhead last night, and found that the small pools were nearly full.

So I immediately changed my plans to go to the Main Pool today to find out if it had filled, and my wife Susan and son Matthew came along.

It was quite amazing to see pools this early in the season. The scene at the Vernal Pool trailhead was incongruous. Amidst the dead brown vegetation from 2003-2004 growth were two sparkling full pools! I later compared my pictures from today to pictures from previous years, which showed the usual situation of extant pools only surrounded by green vegetation.

Susan spotted two coyotes almost right away, with one slightly smaller than the other. But we had to devote most of our attention to the trail, which was muddy in some spots, and had standing water in others.

We hurried to the signboard where we could see the Main Pool, partly in anticipation of finding out whether it had filled, and partly due to the cool breezy conditions. The Main Pool had just barely filled, showing some water from our vantage point, but not much.

At the boardwalk, the water was only 0-2 inches deep, with most of the water in the slightly deeper portion more toward the center of the Pool. But that didn't stop the spadefoot toads from laying their eggs. We found about seven sets of eggs, including one set that was no longer in the water.

This is the third time in the last four years that the Main Pool has not been full when it first formed. In contrast, in the four previous years in which the Main Pool filled, the Pool was completely or nearly full when it formed, 16 inches deep at the boardwalk. So the poor pool animals again have to depend on further rainfall in the next week or two to live out their full life cycle.

On the way back, Susan spotted a tarantula which hardly seemed alive, but it was. It seemed to be huddling its legs close to its body to keep warm. I don't think tarantulas expect to have such cold wet weather in mid-October!

The bloom was pretty pathetic overall. The lack of annuals, due to the half-normal rainfall this year, was evident since there was only a single Stephanomeria diegensis, San Diego wreathplant, a single Trichostema lanceolatum, vinegar weed, and only a handful of Holocarpha virgata ssp. elongata, sticky tarweed, on the trail. However, even a single plant of vinegar weed or sticky tarweed is a delight due to their wonderful smell when touched.

See Complete List of Species in Bloom.

30 December 2004: Vernal Pool Trail (see Vernal Pool Trail Plant Guide)

The heavy rains of yesterday washed out many of the bridges over creeks, so botanizing a new trail was not possible. So I decided just to check out the Main Pool, which I hadn't visited for a couple of weeks, and the hikeable portion of the Vernal Pool Trail.

At the trailhead, I asked a family of four if they had seen anything interesting, and was much surprised at their careful observations and accounting of what they had seen at the Pool. My surprise was because the vast majority of visitors aren't even able to see the fairy shrimp without help; this family had found 11 different critters, and had easily even identified mating pairs of fairy shrimp. I could identify most of the critters for them from their description, but several descriptions eluded my coming up with identification for them.

I told them I was headed to the pool, and I'd be happy to have them come along and I'd try to identify those critters. They turned around to come along, and I was very glad they did. At the pool, it turned out that they had found three things I couldn't immediately identify out of their list of eleven. I took samples of those three in order to try to identify them.

One critter turned out to be a copepod that had honking egg cases, which I had seen plenty of in prior years, but had simply forgotten what they looked like in that state.

Another critter turned out to be something I had not noticed before: the larvae of a water scavenger beetle (order Coleoptera; family Hydrophilidae). There is a picture in the Field Guide To Animals Of Vernal Pools, by Kenney and Burne, p. 52, that looks just like it.

Finally, they pointed out vast drifts of what looked like seeds or egg cases floating on top of the water, with a diameter of ~0.1 mm. Under the microscope, they are clearly not empty or full egg cases. Although they are roughly the same size as fairy shrimp cysts, which are ~0.15 - ~0.40 mm in size, they have a smooth surface, not the richly textured (~honeycombed) surface of fairy shrimp cysts.

The mystery objects appear black, hard, and look like tiny popcorn flower, Plagiobothrys, seeds. Unfortunately, they are too round and too small to be that; the vernal pool popcorn flower, Plagiobothrys undulatus, has nutlets 1.0-1.6 mm in diameter, 10-20 times bigger.

I examined other potential plant species, but none of the most likely suspects fit. (I ruled out Downingia; goldfields, Lasthenia californica; Blennosperma; and curly dock, Rumex crispus, based on seed size or other characteristics.)

I suspect they might be seeds of an annual that grows at the edges of the pool. I'll plant some and see what comes up. (;-)

The pool itself was deeper than I'd ever seen it: it was 19 inches deep, 3 inches deeper than its normal maximum depth! One didn't need a measurement to see the height, because the boardwalk was covered with water in three places. One of those locations had water at least an inch deep. Of course, if the boardwalk hadn't been vandalized ~5 years ago, by removing rocks under a few of the columns supporting the boardwalk, the entire boardwalk would have remained above the water surface.

Runoff had clearly poured into the pool faster than it could drain out the outlet, and the pool was only slowly working off the excess. There were water deposits on the "dry land" on the far side of the pool, as much as ~50 feet beyond the boardwalk! The deposits were clumps of the popcorn flower that formerly were floating in the pool at the surface, when the depth was ~13 inches before the storm. So the maximum water depth might have been as much as a foot deeper!

The Santa Rosa fairy shrimp were still hanging in there, looking better than the last time I checked them. Their maximum density was ~10 per square foot, with many of them mating. There were zillions of Cyclops, some Daphnea, a few seed shrimp, and one midge fly larvae.

After the fun at the pool, I continued on the Vernal Pool Trail to the lip of the Mesa, in order to check out a few areas.

First, I checked the bloom status of the patch where Kay Madore and I had observed the first Blennosperma and peppergrass, Lepidium nitidum, blooming two weeks ago. A few more Blennosperma were blooming, but the peppergrass were all in seed, even though they were only 1-2 cm (<~1 inch) high!

Second, no shooting stars, Dodecatheon clevelandii ssp. clevelandii, were blooming anywhere along the trail, despite them being in full bloom near the junction of Waterline and Monument Hill Roads.

Third, not much was happening at the dropoff other than a single plant of the white-flowering currant, Ribes indecorum, in full bloom. I examined its blooms to compare with the chaparral currant, Ribes malvaceum var. viridifolium, on the Vista Grande Trail. As I had seen in the Santa Monica Mountains, it turned out to be indistinguishable from the R. malvaceum in the shape of its hypanthium, despite that being part of the key to distinguish the species in the Jepson Manual. But in addition to the obvious difference in the flower color, the sepals were reflexed, not spreading, and the flowers were coming out of most nodes on the stem, and were not primarily terminal.

On the way back, I checked out how muddy the Los Santos Trail was. The trail was passable where pea gravel had been spread on it, but at the curve at mile 0.20, a streamlet was running along the length of the trail. It was way too muddy to contemplate going farther.

On my drive to the Visitor Center along Tenaja Road, I noticed a huge pond along part of the Mortero Trail. Clearly, many of the trails need to dry out for perhaps a week before hiking is possible again on them.

2 February 2005: Vernal Pool, Adobe Loop, Punta Mesa, S. Trans Preserve Trails; Monument Hill Road (see Plant Guides)

A non-botanical friend of mine was visiting from the east coast, so this was mostly a hiking trip, with a little botany. I didn't much mind the absence of intensive botany, since the SRPER has been closed for nearly a month, and I wanted to see a larger portion than I would have seen if I had more intensively botanized there today.

Today's trip was an ~8.5 mile loop. The trails were in great shape overall and surprisingly dry. There were only a few muddy spots requiring care to cross; the mud was even dry and cracked in places. Ranger Kevin Smith and others had done a lot of work to improve drainage and fix bridges.

The perc pit at mile 0.19 on the Vernal Pool Trail was quite interesting today. First, the long-awaited tadpoles have finally made an appearance! The sides of the pond were dense with tadpoles, who were curiously inactive. Second, we saw a curious new bug in the perc pit. It was a little red bug, determinedly swimming about, that looked like a spider or tick. It turned out to be a perfect match for the picture of a red water mite, Hydrachna sp., in Kenney and Burne's Field Guide to the Animals of Vernal Pools.

The Main Pool was still filled with critters, even some very-aged Santa Rosa Plateau (but still healthy and normal-looking) fairy shrimp were hanging in there, still mating! (Did anyone put Viagra in the Pool???) We didn't see any tadpoles in the Main Pool yet, but we did finally see some more Spadefoot Toad eggs.

The boardwalk itself had changed in the center, and sloped much worse than it had done before the torrential rain. It probably had floated one leg off a support, or another leg onto a higher rock. (Carole Bell took a picture of the end of the boardwalk floating immediately after the torrential rain.)

There was a very unusual amount of bloom for early February. We saw abundant shooting stars, Dodecatheon clevelandii ssp. clevelandii; western buttercup, Ranunculus occidentalis; red maids, Calandrinia ciliata; wild cucumber, Marah macrocarpus var. macrocarpus; white-flowering currant, Ribes indecorum, and johnny jump-up, Viola pedunculata, in many places on many trails.

The biggest surprise of all was the number of chocolate lilies, Fritillaria biflora var. biflora, on the S. Los Santos and S. Trans Preserve Trails, that are beginning their bloom.

Finally, we found an African daisy, Dimorphotheca sinuata, that is typically planted along freeways, deep inside the SRP, along Monument Hill Road near Monument Hill. I nabbed it to weed it, id it, and voucher it. Carole and Zach report that they continue to find similar single individuals along the roads, possibly spread by fire trucks.

One of my main goals was to check on the subspecies of milkmaids, Cardamine californica. The Western Riverside County Checklist by Roberts et al, which just came out late in 2004, listed only var. integrifolia as being present. This seemed quite odd to me, since the dominant Southern California subspecies is supposedly var. californica, and I had previously determined that the SRP plants were indeed clearly that variety, at least on the Vista Grande Trail. (Lathrop and Thorne had declined to state a variety explicitly.)

There were two locations of these plants on today's trip, and both of the populations were clearly var. californica. The difference in the JM is that var. californica mostly has toothed, ovate leaflets; var. integrifolia has mostly entire, oblong leaflets. In total, I observed and photographed something like 20-30 plants; every one of them had only ovate, toothed leaflets except for a single plant or two which had its uppermost cauline leaf with oblong, entire leaflets (the lower leaves were all ovate and toothed on those plants as well).

By the way, this was quite different from what I had seen at Torrey Pines on 1/13/05. There I had declined to call a variety, since the plants were a total mixture of the two types of leaves.

The hike ended with the highlight: a first-hand experience of how easy it is to mistake a bobcat as a mountain lion. See Bobcats at the Santa Rosa Plateau.

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Copyright © 2004-2005 by Tom Chester.
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Updated 4 January 2005.