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Structural heterogeneity predicts ecological resistance and resilience to wildfire in arid shrublands

May 24, 2024


Dynamic feedbacks between physical structure and ecological function drive ecosystem productivity, resilience, and biodiversity maintenance. Detailed maps of canopy structure enable comprehensive evaluations of structure–function relationships. However, these relationships are scale-dependent, and identifying relevant spatial scales to link structure to function remains challenging.


We identified optimal scales to relate structure heterogeneity to ecological resistance, measured as the impacts of wildfire on canopy structure, and ecological resilience, measured as native shrub recruitment. We further investigated whether structural heterogeneity can aid spatial predictions of shrub recruitment.


Using high-resolution imagery from unoccupied aerial systems (UAS), we mapped structural heterogeneity across ten semi-arid landscapes, undergoing a disturbance-mediated regime shift from native shrubland to dominance by invasive annual grasses. We then applied wavelet analysis to decompose structural heterogeneity into discrete scales and related these scales to ecological metrics of resilience and resistance.


We found strong indicators of scale dependence in the tested relationships. Wildfire effects were most prominent at a single scale of structural heterogeneity (2.34 m), while the abundance of shrub recruits was sensitive to structural heterogeneity at a range of scales, from 0.07 – 2.34 m. Structural heterogeneity enabled out-of-site predictions of shrub recruitment (R2 = 0.55). The best-performing predictive model included structural heterogeneity metrics across multiple scales.


Our results demonstrate that identifying structure–function relationships requires analyses that explicitly account for spatial scale. As high-resolution imagery enables spatially extensive maps of canopy heterogeneity, models for scale dependence will aid our understanding of resilience mechanisms in imperiled arid ecosystems.

Publication Year 2024
Title Structural heterogeneity predicts ecological resistance and resilience to wildfire in arid shrublands
DOI 10.1007/s10980-024-01901-4
Authors Andrii Zaiats, Megan E Cattau, David Pilliod, Rongsong Liu, Patricia Kaye T. Dumandan, Ahmad Hojatimalekshah, Donna M. Delparte, Trevor Caughlin
Publication Type Article
Publication Subtype Journal Article
Series Title Landscape Ecology
Index ID 70254539
Record Source USGS Publications Warehouse
USGS Organization Forest and Rangeland Ecosystem Science Center