Can land management buffer impacts of climate changes and altered fire regimes on ecosystems of the Southwestern United States?
Using two mechanistic ecosystem-fire models, Fire BGCv2 in the Jemez Mountains and LANDIS-II in the Kaibab, the authors projected contemporary climate and two future emissions scenarios (“warm-dry” and “hot-arid”) to the year 2100 to predict changes to forests and fire regimes in a ponderosa pine and a mixed-conifer ecosystem. They also modeled four management strategies (suppression-only, current treatment intensity, and three and six times current treatment intensity) to see if management may be able to counteract the effects of climate change on forest composition and structure.
Only the FireBGCv2 model in the Jemez mountains projected an increase in fire frequency and high-severity fire due to the predicted increases in temperature and moisture deficit. Both models did predict fundamental and persistent shifts in forest structure and composition. Under the hot-arid climate scenario, ponderosa pine forests were type converted to shrublands under altered fire regimes (increased fire frequency and severity) along with regeneration failure. Mixed-conifer forests were affected to a lesser degree.
Management at the varying intensities was unable to prevent the structural and compositional changes to either ecosystem or changes to the fire regime suggesting that novel management approaches will be necessary to counteract the effects of climate change.