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Filazzola NSTP Presentation 2014

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York University Conference talk for Northern Studies Training Program. Presentation examines the cost of facilitation for cushion plants in the alpine.

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Filazzola NSTP Presentation 2014

  1. 1. Variation in cushion traits is determined by feedback effects from beneficiaries Filazzola, A. & Lortie, C.J.
  2. 2. Facilitation Filazzola and Lortie 2014. Global Ecology and Biogeography
  3. 3. Alpine facilitation
  4. 4. …but at what cost? + -
  5. 5. Beneficiary cover Schöb et al. 2013. Functional Ecology
  6. 6. Hypothesis The abundance of beneficiary species negatively co-vary with cushion-plant traits, particularly reproduction, because of a parasitic consumption of microsite resources.
  7. 7. A. Ruttan
  8. 8. A. Ruttan
  9. 9. Methods Landscape Characteristics Cushion Traits Beneficiary Traits 140 cushion 9 sites
  10. 10. Statistics Site Characteristics Cushion Traits Beneficiary Traits S1 S2 S3 Sn C1 C12 C13 C1j C21 C31 Ci1 Cij B1 B12 B13 B1j B21 B31 Bi1 Bij
  11. 11. Statistics Step 1 • PCA of landscape vs. Cushion • Step-wise regression to reduce cushion traits Step 2 • PCA of cushion vs. beneficiary abundance Step 3 • GLM/GLMMs of key variables
  12. 12. N.S. Lat x Long Exposure PAR Disturbance
  13. 13. Step: AIC666.79 Benf ~ Surface.area + Pen + Fruit.Den + Fruit.ht Trait Df F Value Pr(F) + Decad 1 1.77 0.18460 - Pen 1 2.67 0.10434 + Site 1 0.79 0.37517 + SWC.per 1 0.58 0.44686 + Dx 1 0.39 0.53334 + Concav 1 0.07 0.77806 + Branches 1 0.05 0.81705 + SWC.cen 1 0.00 0.96021 - Surface.area 1 5.16 0.02456 * - Fruit.ht 1 5.19 0.02423 * - Fruit.Den 1 5.43 0.02120 *
  14. 14. High cushion Fitness
  15. 15. Beneficiary vs. fitness
  16. 16. Surface area
  17. 17. (Beneficiary ~ Fitness) – Surface area
  18. 18. Results summarized Cushion fitness is not generally effected by site characteristics The surface area of the cushion is correlated with both cushion fitness and beneficiary cover Beneficiary cover is the strongest determinant of cushion fitness
  19. 19. Competition for resources He et al. 2013. Plant Species Biology
  20. 20. Resource Island
  21. 21. Why Fitness? • Seed set/fitness is associated with competitive strength and availability of soil resources (Cornelissen et al. 2003) • Competition in nutrient-poor systems strongly determines plant fitness (Aerts 1999) • Reducing a plants fitness is a form of competition • Easily measurable response
  22. 22. Liczner & Lortie. NSTP Conference 2014
  23. 23. Implications Previous studies have examined functional variability of plants because of cushions Cushion Open Almeida et al. 2012. Plant Ecology & Diversity
  24. 24. Implications Other studies have examined functional variability of strictly cushions He et al. 2013. Plant Species Biology
  25. 25. Implications Findings are similar to that of Schöb et al. 2013 Community Ecology Theory Plant trait research Dominants i.e. cushions Plant trait research Subordinates i.e. beneficiaries
  26. 26. Extension of methodology Albert et al. 2010. Journal of Ecology
  27. 27. Conclusions Further support for the cost-of-facilitation theory (in terms of fitness) Highlight necessity of treating a plant community as a response surface
  28. 28. Thank you!
  29. 29. Links Presentation http://www.slideshare.net/AFilazzola/filazzola-nstp-presentation- 2014 R-Script http://dx.doi.org/10.6084/m9.figshare.1225923
  30. 30. Appendix • Removing surface area effects Beneficiary effects not attributable to surface area Surface Area m2 Beneficiary Cover

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