Observations of the Main Vernal Pools on the Mesa de Colorado in 1996 - 1997

Introduction to this page.

The plot below shows the pool depth (green) versus time at the boardwalk, which is at the edge of the pool. Hence the depth at the center of the pool is slightly greater than reported here. The plot also shows the total rainfall (blue) at my house in Fallbrook, 11 miles south.

(Click on graph for bigger and better image.)

1996 November 24: The pools had no water in them at all, even though 5" of rain had fallen in Fallbrook.

1996 December 17: The rain of 10-11 December 1996 did the trick. The two pools at the Vernal Pool Trailhead and the main pool had a lot of water in them. The water depth was about 0.2 m(7") at the boardwalk over the big pool, several inches below the bottom of the boardwalk platform. Ducks were present on all three pools.

There were a lot of tiny creatures, a few mm (0.1") in size, that were hopping around on the surface of the pool. Typical hops were about 1 cm (0.5"). They may be springtails.

1997 January 11: The tiny creatures were gone, replaced by much less numerous other life forms, such as a wriggling small red worm-like creature, something that looked like it could be some sort of parasite (all mouth and little body), and more numerous "black dots" that quickly landed on my hand, when placed in the water to measure the water depth.

Fairy Shrimp have begun to appear. You have to look hard for them, and the density was low, but they are there. In a column of water one foot square, I observed no more than 3 at once, and typically 0-1.

1997 January 17: Lots of fairy shrimp now. The most numerous things in the pool are bright red shrimp. Also, there are some worm-like things on the surface that are 3-4 mm long.

The water is deep enough that you have to hop from rock to rock to get onto the boardwalk at the near end of the trail in order to not get your boots wet. It isn't possible to leave the other end of the boardwalk without getting wet.

1997 January 30: Very few hoppy things now. There are 3 main shrimp in the water now:

If anyone has the proper identification of these three creatures, please let me know.

The submerged grasses are covered with algae now, that have very fine hairs growing from them.

An extension to the boardwalk is in place now, so that one can get to the boardwalk without getting wet or rock-hopping.

1997 March 7: The two pools by the trailhead are nearly gone. The main pool is significantly lower - the extension to the boardwalk is no longer needed. The surface is about 80% covered by algae. The helmet shrimp are mostly either mating or carrying eggs, although I am not sure whether some were actually molting instead of mating. There are a few tadpoles or other such large creatures in the pool.

1997 March 19: One of the two pools by the trailhead is completely gone, and the other is about 90% gone. The main pool is much lower now, and most of the shrimp are gone. The surface is largely covered by algae, but there are a few clear areas where you can see the few shrimp that are left.

1997 April 8: The two pools by the trailhead are completely dry and grass-covered. The main pool is on the verge of going. Thick mats of algae cover it, and the ground on the high side of the boardwalk is coated with dried mats. At the near end of the boardwalk to the trail, the ground is covered by a low (1-2") sweet-smelling plant with a tiny white flower.

The Plateau away from the pool has the following plants in bloom: blue dick; a blue-flowered plant in the morning glory family, up to 1' high, with tightly curled buds like a morning glory that open to a bowl shape with tightly overlapping petals; a short plant resembling owl's clover; a yellow "buttercup" with 5 petals, 1.5-2' tall, probably in the rose family; and an "iris-like" plant with blue flowers with 6 petals, about 9" high, with stems branching out from the center of the plant.

1997 April 29: The water in the main pool is completely gone, as far as can be seen from the boardwalk. All three pools are seas of dark and light green with no other color. The mats of algae are all dessicated and separated by large drying cracks. The sweet-smelling plants with a tiny white flower are nearly finished blooming, but still make the boardwalk area smell nice, and are accompanied by little purple flowers that have 4 purple petals with yellow inner portions. An onion-type plant is numerous.

The Plateau away from the pool has the following plants in bloom: Lupine, monkey flower, purple poppies? with 3 petals about 1' high with 6 black stamens around the central pistil, no leaves, look very similar to california poppies; a few blue dicks; 2'-high blue penstamon? or larkspur? - spike that is 10 flowers high, with 20-30 flowers on it; little purple flowers about 3" high, 6 petals; lavender flowers on 2-3' stalks are mostly finished, just last flowers at end of stalk; and 1.5-2'-high plants with fat white buds, but no open flowers. The flowers mostly are between the Vernal Pool Trailhead and the Trans Preserve Trail. From the Trans Preserve Trail to the main pool, it looks like a field of wheat. The buttercups have all gone to seed.

I nearly stepped on a 4-5' long snake laying across the entire width of trail just past the Los Santos Trail! Fortunately, it had no rattles and remained motionless while I stepped over it. There also was a cute line of ants carrying the arrow-shaped seeds which have a corkscrew tail, as well as what looked like dandelion-type seeds with white fluff very visible. It looked just like those ant trails in the rain forest you see on nature programs on TV!

1997 later: Actual observations will be added later - I made the mistake of putting them on audio tape and now need to find the tape and transcribe it. The pool never had any noticeable-from-a-distance blooms! The Reserve was burned off, which turned everything into black ashes except for the pools themselves.

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Copyright © 1997-2000 by Tom Chester.
Permission is freely granted to reproduce any or all of this page as long as credit is given to me at this source:
Comments and feedback: Tom Chester
Updated 16 January 1998 (typos corrected 15 July 2000).