1. Climate-induced Shifts in Fire Frequency, and Resulting Effects on Stand Composition Carissa D. Brown Northern Biogeography Lab Department of Geography, Memorial University

2. Black spruce (Picea mariana)

3. Fire drives secondary succession and species distribution in boreal forests

4. Short window of opportunity

5. Temperature trends (1960-2009) Burrows et al. 2011 Science; Chapin et al. 2005 Science

6. Climate-fire regimes Flannigan et al. 2005 Ratio of 3xCO2 / 1xCO2 area burned:

7. Climate-fire-succession Balshi et al. 2009 Kasischke and Turetsky 2006

8. Fire drives secondary succession and species distribution in boreal forests What happens if fire regimes change?

9. How will changes in fire-climate interactions effect black spruce distribution?

10. 1990 1991

11. 1990 1991 2005

12. mature forest long- interval fire short- interval fire

13. mature forest

14. long-interval fire

16. short-interval fire

17. mature forestlong-interval burnshort-interval burn Post-fire colonisation: is seed available?

18. Seed availability mature forest LISI short interval Number of viable seeds/m 2 /year 0 2 4 6 8 Brown and Johnstone, 2012, For. Ecol. Man. long interval Fire history

19. Will seed germinate and survive?

20. Number of emerged seedlings Fire history Brown and Johnstone, 2012, For. Ecol. Man. Black spruce emergence

21. fire return interval seed availability establishment growth and survival long short seed Closely timed fires short-circuit regeneration cycles

22. A failure in two parts 1.Lack of seed 2.Unsuitable substrate

23. A failure in two parts Long-term disruption

24. Indirect climate effects caused by a change to the disturbance regime may initiate vegetation shifts of a larger magnitude or opposite direction than would happen due to climate alone

25. mammal

26. Carbon storage

28. wood organic horizon 1990/91 2005 mature forestlong-interval burnshort-interval burn Fire history

29. How will shifting fire regimes influence tree distributions in the boreal forest? If serotiny loses its advantage (ecosystems become less resilient), what will succeed?

30. The prediction Regions that have experienced a novel disturbance regime will become more suitable for alternative tree species dominance

31. Dalton Complex, Alaska Boundary Fire, Alaska Taylor Complex, AlaskaEagle Plains, Yukon Black spruce ecosystems

33. Future scenarios for successional shifts black spruce self-replacement historic regime severity frequency BS seed severity frequency BS seed moisture In the absence of seed limitation

34. Current distributions Black spruce

35. Current distributions Black spruce White spruce

36. Current distributions Black spruce White spruce Paper birch

37. 50 km Black spruce White spruce Paper birch

38. Shifting regimes in Labrador

39. …and many, many field assistants, labmates, and colleagues. ACKNOWLEDGEMENTS Dr. Jill Johnstone, University of Saskatchewan

40. 050100150200250 0 1 2 3 4 5 Mean stand age Seedling density. m 2 Stand recovery to 4000 trees/ha Viglas, Brown, et al. in review, Can. J. Forest Research High severity fire (good post-fire seedbed) Low severity fire (poor post-fire seedbed) Thresholds for stand recovery Range of seed requirements Threshold for recovery: 50 – 150 years

41. Patterns between species: Alaska Number of seedlings Soil moisture (%) Black spruceAlaskan birch Species-specific optimal seed bed conditions