1. Does Allelopathy Explain the Scarcity of Spruce and Fir Trees in the Beech Gaps of Great Smoky Mountains National Park? Monica Poteat Dr. David Vandermast Elon University

2. Beech Gaps Great Smoky Mtns. High elevations Deciduous – American beech (Fagus grandifolia) Evergreen – Red spruce (Picea rubens) – Fraser fir (Abies fraseri)

3. Other Theories Height difference (Whitaker 1956) Inadequate seed rain (Pavlovic 1981) Lack of shade tolerance (Harlow et al. 1991) Beech soil pH/chemistry (Russell 1953; Fuller 1977)

4. Allelopathy The production of biomolecules by one plant species which can inhibit the germination and/or growth of other plant species (Rizvi et al. 1992)

5. Hypothesis Beech allelopathy inhibits the germination and mass accumulation of red spruce and Fraser fir seeds

6. Experimental Set-Up Species Used: Lettuce (Lactuca sativa) Red spruce Fraser fir Soil Treatments: Top Soil Beech forest soil Watering Treatments: Deionized Water Leachate – 1:5 ratio of beech forest leaves and deionized water

7. Treatment Set-Up Top Soil/ dH 2 0 Beech soil/ dH 2 0Top soil/Leachate Beech soil/ Leachate

8. RESULTS: LETTUCE Top Soil/ dH 2 0 Beech soil/ Leachate

9. A AB B Average Germination of Lettuce

10. Top soil- dH 2 O Beech soil- dH 2 O Top soil- Leachate Beech soil- Leachate A B A B Treatment Average ABM of Lettuce

11. RESULTS: RED SPRUCE Top soil- dH 2 O Beech soil- Leachate

12. A AB B Average Germination of Red Spruce

13. Top soil- dH 2 O Beech soil- dH 2 O Top soil- Leachate Beech soil- Leachate Treatment A B A AB Average ABM of Red Spruce

14. RESULTS: FRASER FIR Top soil- dH 2 O Beech soil- Leachate

15. A B AB Average Germination of Fraser Fir

16. Top soil- dH 2 O Beech soil- dH 2 O Top soil- Leachate Beech soil- Leachate Treatment A B AB C Average ABM of Fraser Fir

17. Important Findings Leachate germinations all lower than deionized water (even if not statistically significant) Leachate and/or beech soil treatments significantly reduce germination and/or mass – Different species respond differently to allelogens Sickly seedlings

18. What our findings mean in relation to... Other allelopathic studies – American beech leaf leachate has been shown to lower leaf area and biomass of the seedlings of sugar maple (Hane et al. 2003) Competitive Exclusion Beech Bark Disease

19. Beech are a foundation species within gaps – Define community – Create stable conditions Why is this important? http://fisc.er.usgs.gov/c1258_Dodd/circ1258_8a.jpg

20. Conclusion Allelopathy is an important mechanism through which beech forests competitively exclude the red spruce and Fraser fir.

21. Acknowledgments Dr. Vandermast Elon University SURE program Elon College Fellows Program Great Smoky Mountains National Park (permits) – Keith Langdon, Supervisor of Science Projects – Dr. Michael Jenkins, Ecologist Judy Poteat