Getting to the root of the matter: landscape implications of plant-fungal interactions for tree migration in Alaska
- 467 Downloads
Forecasting the expansion of forest into Alaska tundra is critical to predicting regional ecosystem services, including climate feedbacks such as carbon storage. Controls over seedling establishment govern forest development and migration potential. Ectomycorrhizal fungi (EMF), obligate symbionts of all Alaskan tree species, are particularly important to seedling establishment, yet their significance to landscape vegetation change is largely unknown.
We used ALFRESCO, a landscape model of wildfire and vegetation dynamics, to explore whether EMF inoculum potential influences patterns of tundra afforestation and associated flammability.
Using two downscaled CMIP3 general circulation models (ECHAM5 and CCCMA) and a mid-range emissions scenario (A1B) at a 1 km2 resolution, we compared simulated tundra afforestation rates and flammability from four parameterizations of EMF effects on seedling establishment and growth from 2000 to 2100.
Modeling predicted an 8.8–18.2 % increase in forest cover from 2000 to 2100. Simulations that explicitly represented landscape variability in EMF inoculum potential showed a reduced percent change afforestation of up to a 2.8 % due to low inoculum potential limiting seedling growth. This reduction limited fuel availability and thus, cumulative area burned. Regardless of inclusion of EMF effects in simulations, landscape flammability was lower for simulations driven by the wetter and cooler CCCMA model than the warmer and drier ECHAM5 model, while tundra afforestation was greater.
Results suggest abiotic factors are the primary driver of tree migration. Simulations including EMF effects, a biotic factor, yielded more conservative estimates of land cover change across Alaska that better-matched empirical estimates from the previous century.
KeywordsAlaska ALFRESCO Climate change Ectomycorrhizal fungi Treeline Wildfire
The Scenarios Network for Alaska and Arctic Planning, the Alaska Climate Science Center, and the Joint Fire Science Graduate Research Innovation Award supported this research. We thank Shalane Frost for creating Figs. 4 and 7. The project described in this publication was supported by Cooperative Agreement Number G10AC00588 from the United States Geological Survey. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the USGS.
Conflict of interest
The authors declare that they have no conflict of interest.
- Bent E, Kiekel P, Brenton R, Taylor DL (2011) Root-associated ectomycorrhizal fungi shared by various boreal forest seedlings naturally regenerating after a fire in Interior Alaska and correlation of different fungi with host growth responses. Appl Environ Microbiol 77(10):3351–3359CrossRefPubMedPubMedCentralGoogle Scholar
- Breen AL, Bennett AP, Hewitt RE et al (2013) Tundra fire and vegetation dynamics: simulating the effect of climate change on fire regimes in Arctic ecosystems. Paper presented at the American Geophysical Union Fall Meeting, San Fransisco, 9–13 December 2013Google Scholar
- Gray ST, Bennett AW, Bolton WR, Breen AL, Carman T (2013) Using integrated ecosystem modeling to understand climate change. Alaska Park Sci 12(2):1–17Google Scholar
- Hewitt RE (2014) Fire-severity effects on plant-fungal interactions: implications for Alaskan treeline dynamics in a warming climate. PhD thesis, University of Alaska FairbanksGoogle Scholar
- Horton TR, Bruns TD, Parker VT (1999) Ectomycorrhizal fungi associated with Arctostaphylos contribute to Pseudotsuga menziesii establishment. Can J Bot 77(1):93–102Google Scholar
- Larsen JA (1980) The boreal ecosystem. Academic Press, New YorkGoogle Scholar
- Lloyd AH, Fastie CL (2003) Recent changes in treeline forest distribution and structure in interior Alaska. Ecoscience 10(2):176–185Google Scholar
- Rupp TS, Duffy P, Leonawicz M et al (2015) Climate scenarios, land cover, and wildland fire. In: Zhu Z, McGuire AD (eds) Baseline and projected future carbon storage and greenhouse-gas fluxes in ecosystems of Alaska. U.S. Geological Survey Professional Paper (In press)Google Scholar
- Scenarios Network for Arctic and Alaska Planning (2015) Average summer temperature data download. University of Alaska. Available from http://www.snap.uaf.edu/tools/data-downloads, Accessed 16 March 2015
- Smith SE, Read DJ (2008) Mycorrhizal Symbiosis. Academic Press, New YorkGoogle Scholar
- Starfield A, Cumming D, Taylor R, Quadling M (1993) A frame-based paradigm for dynamic ecosystem models. Ai Appl 7(2&3):1–13Google Scholar
- Viereck LA, Dyrness CT, Batten AR, Wenzlick KJ (1992) The Alaska vegetation classification. General Technical Report PNW-GTR-286 U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Portland, p 278Google Scholar