Potential For Change After Mountain Pine Beetle (MPB) Attack: Ecosystem Dynamics During the Early Red Attack Phase Drs. Anne C.S.
1 McIntosh
& S. Ellen
2 1 Macdonald , Alberta
Biodiversity Monitoring Institute,
I. INTRODUCTION & METHODS
2University
of Alberta, Edmonton, AB
II. RESULTS*
• MPB, Dendroctonus ponderosae, is a native bark beetle of western North America pine forests
Downed Wood -1
Down woody material (Megagrams ha )
Overstory Basal Area
• However, MPB has expanded its range north & east into Alberta - changing the disturbance regimes for attacked lodgepole pine forests in Alberta • We are studying relationships between the overstory, understory, & below-ground dynamics of western Alberta lodgepole pine stands (near Robb, AB) with different simulated MPB attack levels and/or forest management:
i. Control ii. 50% MBP mortality
70 60
Pre-treatment Treatment Post-treatment B AB
50
A
40 30 20 10 0
Control
50%kill 100%kill Salvage
Year
Treatment/Year
iii. 100% MPB mortality
Understory Plant Community
iv. Clearcut salvage harvest after MPB attack
Growth Form Response
• MPB attack was simulated using glyphosate herbicide (applied summer 2009) • We used a repeated measures randomized block design; overstory, understory, and below-ground data were collected each of 3 summers: pre-treatment (2008), treatment (2009), and post-treatment (2010)
Community Response
x
y y
Clearcut 50% Kill Control 100% Kill
Forest Floor Microbial Community
x 3 Replicate Blocks
Biomass
Respiration
Ecosystem Dynamics: Above- & Below- ground Linkages
Understory
Overstory
MPB Belowground
??? * Subset of results - error bars are SEs, Multivariate plots are non-metric multidimensional scaling ordinations.
III. CONCLUSIONS •
There was short-term resistance to MPB for most understory & below-ground properties during red attack
•
Dynamics in the salvage harvested stands followed patterns expected post-harvest and were not resistant
• Salvage logging will push these stands in a potentially very different direction than will the modified natural disturbance regime that includes MPB
5) For more information contact: anne.mcintosh@ualberta.ca
V. ACKNOWLEDGEMENTS ACKNOWLEDGEMENTS
IV. REFERENCES •
•
McIntosh, A.C.S., Macdonald, S.E.. In press. Short-term resistance of ecosystem properties and processes to simulated mountain pine beetle attack in a novel region. Ecosphere. McIntosh, A.C.S., Macdonald, S.E.. 2013. Potential for lodgepole pine regeneration after mountain pine beetle attack in newly invaded Alberta stands. Forest Ecology and Management, 295: 11-19.