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The Phoenix Project is a longitudinal investigation dedicated to studying ecological succession
after the devastating Harmony Grove Fire of 1996. Selected as a 1997 Toyota Tapestry Grant awardee,
Integrated Science students at La Costa Canyon High School studied experimental design, soil science,
and the ecology of coastal shrub and chaparral. The goal of the first year of this project was to
develop experimental protocols and a baseline for future studies. The site is located within the
Santiago Peak formation that is predominately metavolcanic rock. Students set up 10 transects on
a site adjacent to the school and using a random number generator flagged over one hundred
sampling sites. The location of these sites was determined by using GPS within decimeter
accuracy after post processing. Students collected soil samples throughout the winter and
spring. Through painful experimentation and comparison to standards, students discovered
that their chemical test results were inaccurate. The data reflects the results of chemical
testing performed at a professional soil testing service. The following map projections
represent a visual documentation of the site in April 1998. As more data is collected and
visualized using GIS and students become more proficient in using this technology,
students will be able to explore independent multi-disciplinary research questions.
A secondary goal of this project involves working with the California Department of
Forestry to educate our community that is situated in the rapidly developing urban
interface zone where fire is a natural part of ecological succession.
This is a visual representation of the perimeters of the dominant species and
their location within the test site. These plants are representative of the coastal shrub community
that predominates after fire. Deerweed is the indicator species of this ecosystem. Black mustard,
a highly invasive non-native, is being tracked because it interferes with the growth of native
species and is highly flammable. Research suggests that this primary community may be succeeded
by species like the sages that are indicative of chaparral.
The pH map is an interpolated surface based upon student generated pH data.
An important factor in determining nutrient uptake and availability, pH helps to determine species
variability. Soil texture tests performed by students revealed that the soil on this site is sandy
loam with underlying clay which was confirmed by the USDA soil survey map. This soil type is part
of the San Miguel/Exchequer Series whose pH range corresponds to our tested values ranging from
5.0-6.6.
The Total Inorganic Nitrogen map is an interpolated surface based upon professional
test results. Nitrogen is the limiting nutrient for plant development in the San Miguel/Exchequer
Series. The formation of clay through the hydration of feldspar forms an impermeable barrier which
causes water soluble nutrients like nitrates and ammonia to be lost to surface runoff. By monitoring
inorganic nitrogen we hope to track competition between nitrogen fixing plants, like deerweed,
and non-nitrogen fixers, like bushmallow. The effects of these species on nitrogen soil levels
will be monitored.
This map, created by LCCHS student Neil Brosnahan, reveals the proximity between
higher pH levels and rocky surfaces. This relationship may be explained by the composition of
metavolcanic rocks. Andesite, a metavolcanic rock, contains the mineral feldspar. Hydrated feldspars
form clay and also form insoluble calcium oxide. Calcium oxide is basic and therefore the pH of
weathered rock should be less acidic.
The Percent Soil Moisture map is an interpolated surface created from professional
soil analysis. Well-drained soils that do not retain moisture are characteristic of the San Miguel/Exchequer
Series because of the underlying clay layer which promotes runoff. Certain species like laurel sumac
are more xeric in nature than other coastal scrub species. Monitoring moisture levels may reveal
relationships between speciesā location and soil moisture content.
The Soil Temperature map is an interpolated surface based upon temperatures taken
by the students in the field. Temperature is being monitored to determine whether there a relationship
between soil temperature and vegetative cover. Extremes in soil temperature may preclude the presence
of certain plant species and can alter enzymatic reactions limiting plant growth.
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