Topography and climate are more important drivers of long-term, post-fire vegetation assembly than time-since-fire in the Sonoran Desert, US

Journal of Vegetation Science
By: , and 

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Abstract

Questions

Do abiotic environmental filters or time-since-fire (TSF) explain more variability in post-fire vegetation assembly? Do these influences vary between vegetation structure and composition, and across spatial scales?

Location

Sonoran Desert of southwestern Arizona, US.

Methods

We measured perennial vegetation in a chronosequence of 13 fires (8-33 yr TSF) spanning a broad regional gradient. The relative influence of environmental filters (topography and climate) and TSF were compared as predictors of long-term, post-fire vegetation assembly. Analyses considered different measures of vegetation structure (cover, height and density) and scales of community organization (species composition, structure and landscape).

Results

Species and growth form composition did not exhibit directional responses with increasing TSF, but sorted along abiotic gradients. Differences in vegetation cover and height between burned and unburned control areas were attributed primarily to gradients of topography and climate. In contrast, vegetation density initially increased in burned areas but declined to pre-burn levels with increasing TSF. The strongest predictors of landscape-scale recovery of vegetation cover, height and density were elevation, post-fire precipitation and average annual precipitation, respectively. Recovery of vegetation height was positively correlated with precipitation in the first year following fire, suggesting that abiotic conditions of the immediate post-fire environment may drive long-term variability in vegetation structure.

Conclusions

We find substantial evidence that environmental filters, rather than TSF, drive the majority of variability in long-term, post-fire vegetation assembly within the Sonoran Desert. Careful consideration of spatial variability in abiotic conditions may benefit post-fire vegetation modelling, as well as fire management and restoration strategies.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Topography and climate are more important drivers of long-term, post-fire vegetation assembly than time-since-fire in the Sonoran Desert, US
Series title Journal of Vegetation Science
DOI 10.1111/jvs.12324
Volume 26
Issue 6
Year Published 2015
Language English
Publisher International Association for Vegetation Science
Publisher location Uppsala, Sweden
Contributing office(s) Western Ecological Research Center
Description 14 p.
First page 1134
Last page 1147
Online Only (Y/N) N
Additional Online Files (Y/N) N