Analysis of Plants Blooming on the Vernal Pool Trail, Santa Rosa Plateau, Vs. Time in 2002

Showiness of the Bloom vs. Time


This page contains up-to-date plots of the number of plants in bloom and the showiness of the bloom for 2002, but contains an analysis of that data set only up to 4/3/02.

For an introduction to the quantities plotted below and discussed here, see Analysis of Plants Blooming on the Santa Rosa Plateau Vs. Time in 2001.

In 2001, I attempted to keep detailed track of the entire bloom on the older section of the Santa Rosa Plateau Ecological Reserve, the part east of Clinton Keith and Via Volcano Roads. In 2002, I am keeping detailed track only of the bloom on the Vernal Pool Trail. Thus all the plots and analysis here pertain only to that trail. (I kept separate records of the bloom on the Vernal Pool Trail in 2001, and hence the 2001 values in this page also pertain only to that trail.)

The time sampling is very different in 2002 as well. In 2001, I sampled the early and peak bloom every 2-4 days, extending the sampling interval to 6-7 days near the end of the bloom. Using that data set, I was able to determine that the data have only a very small variation with periods shorter than a week or two. Hence in 2002 I am sampling the bloom once every week or two, which should be sufficient to follow the bloom well.

The comparison of the 2002 bloom to the 2001 bloom is especially interesting due to the severe drought in 2002 compared to almost-normal rainfall in 2001. In 2002, the Santa Rosa Plateau received only one-fourth of its normal rainfall, 4" compared to 16". Further, the rainfall was mostly received in units of 0.25", which nearly always was followed by drying winds or heat that removed most of the moisture from the soil. As a result, the lower portions of the soil were never moistened - that is, the rain only moistened the upper few inches of soil at most.

Showiness of the Bloom vs. Time

Due to the drought in 2002, the showiness factor for many species is much lower in 2002 than it was in 2001. For example, in 2001 blue-eyed grass produced many patches of blue color along the Vernal Pool Trail that were very impressive. As a result, I assigned this species a showiness factor of "10" on a scale of 1-10 in 2001. In 2002, the number of individual plants blooming at a given time was down by a factor of 10 to 100, and there were no patches of blue color evident anyplace along the Vernal Pool Trail. Sometimes one even had to hunt for the handful of plants blooming at any given time. As a result, the showiness factor is only a "2" in 2002.


As of 4/3/02, it appears that we are near the peak of the showiness for the Vernal Pool Trail for this year, with a peak value about one-third of last year. The peak is likely to occur earlier this year, since many species have already gone out of bloom that were still in bloom much later last year.

The number of species times fullness curve began rising at earlier dates this year, since the drought caused plants to come into full bloom early, as well as finish bloom much earlier than last year. Both these effects cause the number of species blooming curve to now fall below the levels of a year ago.

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Copyright © 2002 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 24 November 2002.