Forest fires and climate-induced tree range shifts in the western US

Avery P Hill,Christopher B Field

doi:10.1038/s41467-021-26838-z

Avery P Hill, Christopher B Field

Open Access

https://doi.org/10.1038/s41467-021-26838-z

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Journal: Nature Communications	Publication Date: Nov 15, 2021
Citations: 13	License type: open-access

Affiliation: Stanford University, Palo Alto Institute

Abstract

Due to climate change, plant populations experience environmental conditions to which they are not adapted. Our understanding of the next century’s vegetation geography depends on the distance, direction, and rate at which plant distributions shift in response to a changing climate. In this study we test the sensitivity of tree range shifts (measured as the difference between seedling and mature tree ranges in climate space) to wildfire occurrence, using 74,069 Forest Inventory Analysis plots across nine states in the western United States. Wildfire significantly increased the seedling-only range displacement for 2 of the 8 tree species in which seedling-only plots were displaced from tree-plus-seedling plots in the same direction with and without recent fire. The direction of climatic displacement was consistent with that expected for warmer and drier conditions. The greater seedling-only range displacement observed across burned plots suggests that fire can accelerate climate-related range shifts and that fire and fire management will play a role in the rate of vegetation redistribution in response to climate change.

Highlights

Due to climate change, plant populations experience environmental conditions to which they are not adapted
Our results contribute to the exploration of the hypothesis that forest fires can facilitate climate-induced range shifts[28,34], providing some of the first empirical evidence of contemporary climate-induced potential range shifts being facilitated by wildfire
Two of the eight species studied showed greater Seedling Only Range Displacement (SORD) in burned areas than unburned areas, and these findings are consistent with current understandings of range shifts, climate change, and disturbance ecology

Summary

Introduction

Plant populations experience environmental conditions to which they are not adapted. Our understanding of the century’s vegetation geography depends on the distance, direction, and rate at which plant distributions shift in response to a changing climate. The greater seedling-only range displacement observed across burned plots suggests that fire can accelerate climate-related range shifts and that fire and fire management will play a role in the rate of vegetation redistribution in response to climate change. The required rates of plant range shifts to keep up with the velocity of climate change are large, relative to observed range shift rates[12] Though these rates are highly variable among taxa, a global synthesis found that plant distributions have been shifting to higher elevations at an average rate of 1.5 m/y8. Range edges are dynamic over time, expanding or contracting as the relationship between a population and its environment changes, because of changes in (1) the environment (e.g., warmer temperatures, increased precipitation seasonality, etc.) and/or (2)

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