1. Limestone, Granite and Vegetation In the Coronado National Forest Onamia Pope August 23, 2000

2. Introduction • Calcareous rock is associated with distinct vegetation • Other studies have correlated limestone with specific vegetation, however few studies have been done in Arizona • The ocotillo appears to dominate vegetation with the presence of limestone

3. Hypothesis • Is there a correlation between the presence of limestone and the abundance of ocotillo? • If there is a correlation, what physical and chemical properties of limestone can explain these differences?

4. Methods • The site was located in the Coronado National Forest • The area chosen was designed to eliminate other variable that could alter vegetation community • The area had little environmental disturbance

5. Methods • Quantitative samples were taken from twenty-three, 25(m2) quadrants • A major rock type for each quadrant was identified. • The number of each dominant species of vegetation was counted. • The percent of cover of rock, grasses and fairy duster was estimate by visual observation.

6. Methods • Latitude and Longitude data was collected using GPS • Data were analyzed using chi-square statistical test and histograms

7. Significance level for limestone occurring with Ocotillo(.0005), Agave(.006). Significance level for limestone occurring without Fishhook cactus (.012). Non-significant results for mesquite and prickly pear occurring with limestone. No new information when tests were expanded to include limestone, granite and shale. Results Chi-squared test results

8. Results

9. Results

10. Results

11. Discussion • Differences observed in the dominance of the ocotillo are a result of physiological requirements • Calcareous soils represent a more arid habitat • The fine texture of limestone allows it to hold more water • Limestone and granite alter the pH of the soil

12. Conclusion • Calcareous soil is a determinate of vegetation • This project is in its infancy stages many factors that were not studied can cause the vegetation present. • More data needs to be collected to determine over a greater time period in order to determine the effects of time on vegetation • Clearly rocks are the most important thing in this world.

13. Rocks Rule