Symphyotrichum pilosum (formerly Aster pilosus)

Commonly known as: White Heath Aster or Frost Aster

Photo courtesy of: http://mdc.mo.gov/discover-nature/field-guide/whit...

By: Lindsey, Danielle, Casey, and Becca

Quadrant Study Results:

  • Dispersal Pattern: aggregated distribution
  • Estimated Population: about 14,000

Ecosystem Description:

Meadow surrounded by disturbed land that slopes down into a valley with a variety of grasses and low-lying perennials (photos below).

Microclimate Description:

Symphyotrichum pilosum grows near disturbed land (xc trail and construction) at the top of the valley. The pH of the soil is neutral, the soil moisture is dry, and it is commonly found amongst large populations of its own species with other low-lying grasses and perennials surrounding (photos below).

Research:

Through our research, we discovered the Symphyotrichum pilosum thrives in a variety of ecosystems around Missouri, including meadows and grasslands. Symphyotrichum pilosum self-germinates, so it's usually the first to grow and repopulate disturbed areas. Symphyotrichum pilosum prefers dry soil and spreads aggressively.

http://mdc.mo.gov/discover-nature/field-guide/whit...

Hypothesis:

If Symphyotrichum pilosum grows near the construction site then the pH of the soil will be basic because the pH of the soil around the construction site is basic.

Procedure:

Calibrate the pH meter using pure water and prepare two jars with pure water. Collect a soil sample in the undisturbed land at the bottom of the valley and mix in jar with water into slurry. Repeat with a soil sample around Symphyotrichum pilosum near the disturbed land.

Results:

The pH of the undisturbed soil and the pH of the soil near Symphyotrichum pilosum are both 7 pH. The hypothesis was refuted because the pH of the soil collected in the undisturbed land was the same as the pH of the soil collected near our plant on the outskirts of the construction, so the pH of the soil has no effect on Symphyorichum pilosums.

Retesting:

While gathering the soil for the pH tests it was observed that the Symphyotrichum pilosum plants grew at the top of the hill and not in the valley. To test this observation a new test was conducted to test the moisture of the soil down in the valley and on top of the hill near the Symphyotrichum pilosum. The test was conducted within 24 hours of rainfall. A shovel was used to dig a hole in which a wooden dowel was placed to measure the moisture of the soil in the valley and near Symphyotrichum pilosum.

New Hypothesis:

If Symphyotrichum pilosum grows on top of the hill then the soil moisture will be less than the soil moisture at the bottom of the hill because the rainfall will run downhill, leaving the soil near Symphyotrichum pilosum dry.

Results:

The soil moisture at the bottom of the valley was at 3.5 inches deep, whereas the soil moisture near Symphyotrichum pilosum was 6 inches deep. These results demonstrate Symphyotrichum pilosum does prefer areas with low soil moisture. This supports the hypothesis that Symphyotrichum pilosum grows on top of the hill, because the plant prefers areas with low soil moisture.

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