Projected future vegetation changes for the Northwest United States and Southwest Canada at a fine spatial resolution using a dynamic global vegetation model
Dates
Publication Date
2015-10-21
Start Date
2070
End Date
2099
Citation
Shafer, S.L., Bartlein, P.J., Gray, E.M., & Pelltier, R.T. 2015. Projected Future Vegetation Changes for the Northwest United States and Southwest Canada at a Fine Spatial Resolution Using a Dynamic Global Vegetation Model. http://dx.doi.org/10.5066/F73X84PH.
Summary
Future climate change may significantly alter the distributions of many plant taxa. The effects of climate change may be particularly large in mountainous regions where climate can vary significantly with elevation. Understanding potential future vegetation changes in these regions requires methods that can resolve vegetation responses to climate change at fine spatial resolutions. This research was projected using three models: cgcm31, hadley, and current. We used LPJ, a dynamic global vegetation model, to assess potential future vegetation changes for a large topographically complex area of the northwest United States and southwest Canada (38.0–58.0°N latitude by 136.6–103.0°W longitude). LPJ is a process-based vegetation model that [...]
Summary
Future climate change may significantly alter the distributions of many plant taxa. The effects of climate change may be particularly large in mountainous regions where climate can vary significantly with elevation. Understanding potential future vegetation changes in these regions requires methods that can resolve vegetation responses to climate change at fine spatial resolutions. This research was projected using three models: cgcm31, hadley, and current. We used LPJ, a dynamic global vegetation model, to assess potential future vegetation changes for a large topographically complex area of the northwest United States and southwest Canada (38.0–58.0°N latitude by 136.6–103.0°W longitude). LPJ is a process-based vegetation model that mechanistically simulates the effect of changing climate and atmospheric CO2 concentrations on vegetation. It was developed and has been mostly applied at spatial resolutions of 10-minutes or coarser. In this study, we used LPJ at a 30-second (~1-km) spatial resolution to simulate potential vegetation changes for 2070–2099. LPJ was run using downscaled future climate simulations from five coupled atmosphere-ocean general circulation models (CCSM3, CGCM3.1(T47), GISS-ER, MIROC3.2(medres), UKMO-HadCM3) produced using the A2 greenhouse gases emissions scenario. Under projected future climate and atmospheric CO2 concentrations, the simulated vegetation changes result in the contraction of alpine, shrub-steppe, and xeric shrub vegetation across the study area and the expansion of woodland and forest vegetation. Large areas of maritime cool forest and cold forest are simulated to persist under projected future conditions. The fine spatial-scale vegetation simulations resolve patterns of vegetation change that are not visible at coarser resolutions and these fine-scale patterns are particularly important for understanding potential future vegetation changes in topographically complex areas.
The aim of this study was to simulate vegetation responses to climate change at a fine spatial resolution across our topographically complex study area that includes vegetation ranging from xeric vegetation in the interior western United States to mesic vegetation along the Pacific Coast. LPJ, a dynamic global vegetation model, was able to accurately simulate historical vegetation for many parts of the study area when compared with both potential natural vegetation data for the United States and remotely sensed land cover data, providing confidence in the model's ability to simulate vegetation at fine spatial resolutions in topographically complex regions. The simulated future vegetation changes displayed fine spatial-scale patterns of contraction, expansion, and persistence of vegetation, all mediated by the region’s topography. The results of this study improve our understanding of the potential magnitude and complexity of future vegetation changes that may occur in mountainous regions, with the caveat that many uncertainties associated with both projections of future climates and potential vegetation responses to climate change have yet to be resolved.
