Fire modulates climate change response of simulated aspen distribution across topoclimatic gradients in a semi-arid montane landscape

Abstract

Content Changing aspen distribution in response to climate change and fire is a major focus of biodiversity conservation, yet little is known about the potential response of aspen to these two driving forces along topoclimatic gradients.Objective This study is set to evaluate how aspen distribution might shift in response to different climate-fire scenarios in a semi-arid montane landscape, and quantify the influence of fire regime along topoclimatic gradients. Methods We used a novel integration of a forest landscape succession and disturbance model (LAN DIS-II) with a fine-scale climatic water deficit approach to simulate dynamics of aspen and associated conifer and shrub species over the next 150 years under various climate-fire scenarios. Results Simulations suggest that many aspen stands could persist without fire for centuries under current climate conditions. However, a simulated 2-5°C increase in temperature caused a substantial reduction of aspen coverage at lower elevations and a modest increase at upper elevations, leading to an overall reduction of aspen range at the landscape level. Increasing fire activity may favor aspen increase at its upper elevation limits adjacent to coniferous forest, but may also favor reduction of aspen at lower elevation limits adjacent to xeric shrubland. Conclusions Our study highlights the importance of incorporating fine-scale terrain effects on climatic water deficit and ecohydrology when modeling species distribution response to climate change. This modeling study suggests that climate mitigation and adaptation strategies that use fire would benefit from consideration of spatial context at landscape scales.Electronic supplementary material The online version of this article (

Potential influence of wildfire in modulating climate-induced forest redistribution in a central Rocky Mountain landscape

“…For instance, Yang et al (2015) used LANDIS-II to project change in forest cover in a mountain range in northern Nevada and, although their findings regarding climate-fire influence on montane vegetation were generally similar to this study, they did not predict subalpine fir would decline as rapidly. Such differences could be due to regional climate and vegetation differences but were also likely due to use of different global climate models, slightly different species parameters, unique fire regime scenarios, and alternative methods for calculating species establishment probabilities.…”

“…These additional dynamics have been more commonly simulated under climate change using FLSMs (e.g., Yang et al 2015) and dynamic global vegetation models (e.g., Conlisk et al 2012). However, the complexity of such models can obscure fundamental species-climate relationships that determine future climate niche distributions and may be relevant to formulating future conservation actions (e.g., assisted migration).…”

Restoration of the iconic Pando aspen clone: emerging evidence of recovery

“…In relation to climate warming alongside herbivory, we should expect greater opportunity for increased wildfire in seral communities than in stable aspen (Yang et al. ). Drought and warming may increase the pace of mature tree die‐off (Worrall et al.…”

“…, Krasnow and Stephens , Yang et al. ). This resurgence in aspen science is in need of parallel field trials to test developing theory.…”

“…, Yang et al. ). Visual inspection of the Pando clone suggests it is on just such a trajectory today (Appendix ): Where stems are unprotected by fencing, there is little regeneration or recruitment, often a single mature age‐class, and a rapidly dying overstory comprised ramets from 110 to 120 yr of age (DeRose et al.…”