Invasive species
Barred owls and megafire hit native owls differently
Open access · cc by · source: Europe PMC
Flammulated owls declined 71% in severe burns and doubled after barred owl removals; pygmy and great horned owls barely budged.
Study at a glance
- Design
- Other — Passive acoustic occupancy modeling across megafires and barred owl removal experiment
- N
- N=265 · 265 hexagonal survey cells with 517 ARUs; 80 barred owl/hybrid removals
- Population
- Owls across >6,000 km² of the northern Sierra Nevada
- Outcome
- Site occupancy of flammulated, pygmy, and great horned owls after fire and removals
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Severe fire cut flammulated occupancy 71% for ≥3 years in near-complete burns, yet occupancy was higher where some high-severity fire occurred (Ψ 0.29 vs 0.16 unburned). After removals, flammulated occupancy at treatment sites rose from 0.09 to 0.18 (about twofold). Pygmy and great horned owls showed little fire or removal response. No fire×removal interaction. Flammulated occupancy was 196% higher in the most rugged terrain; barred owls declined 84% there.
Methodology
Researchers ran passive acoustic surveys (2018, 2021–2023) across >6000 km2 of the northern Sierra Nevada, bracketing the North Complex and Dixie megafires and a lethal barred owl removal experiment (80 birds). Occupancy models tested fire, invasion, and their interaction for flammulated, pygmy, and great horned owls.
Limitations
Barred owl densities were already low after removals, so interactions could emerge where invaders are denser. Predation on flammulated owls was not directly observed. Great horned habitat coefficients had wide intervals overlapping zero. Surveys cover a few years postfire, not decades of snag-forest succession.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
This library holds 3 empirical papers on invasive species with measured outcomes rather than reviews.
Evidence for the claim as stated.
Flammulated owls declined 71% in severe burns and doubled after barred owl removals; pygmy and great horned owls barely budged.
Evidence for the claim as stated.
A metapopulation model or a local suppression trial does not generalise to every invader.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
A metapopulation model or a local suppression trial does not generalise to every invader.
Related papers in this topic
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