Future dominance by quaking aspen expected following short?interval, compounded disturbance interaction

The spatial overlap of multiple ecological disturbances in close succession has the capacity to alter trajectories ecosystem recovery. Widespread bark beetle outbreaks and wildfire have affected many forests western North America past two decades areas important habitat for native ungulates. Bark prior fire may deplete seed supply host species, differences fire-related regeneration strategies among species shift composition structure initial forest trajectory. Subsequent browsing postfire tree by large ungulates, such as elk (Cervus canadensis), limit grow above browse zone form next canopy. Five stand-replacing wildfires burned ~60,000 ha subalpine that had previously been severe (>90% mortality) spruce (SB, Dendroctonus rufipennis) Engelmann (Picea engelmannii) 2012–2013 southwestern Colorado. Here we examine drivers variability abundance newly established conifer seedlings [spruce fir (Abies lasiocarpa)] resprouts quaking aspen (Populus tremuloides) following short-interval sequence SB (2–8 yr between outbreak fire) at sites where reconstructed severities fire. We then implications ungulate found abundances seedling establishment decreased substantially outbreak. Prolific resprouting stands with live will favor an trajectory dominated aspen. However, preferential ungulates likely slow rate canopy recovery but is unlikely future Collectively, our results show increases vulnerability spruce–fir shifts type (conifer aspen) physiognomic community non-forest). By identifying compounded disturbance interactions are or findings useful developing adaptive management context warming climate shifting regimes.