Resilience and plant growth forms 40 years after a volcanic disturbance

Resilience represents a critical concept in ecology; yet, quantitative assessment of resilience in response to disturbance is rare, even for widely recognized growth forms. Plant groups based on deciduousness, clonality, morphology, and Raunkiaer life form could predict inertia to major disturbances and subsequent resilience. Measurement of plant responses to tephra deposition from the 1980 eruption of Mount St. Helens (USA) provides an excellent opportunity to evaluate differences in resilience among groups of forest understory species near the world's most‐studied volcano. We use data from four sites, and >600 plots, quantifying resilience among different plant growth forms during 40 years of post‐disturbance succession. We found that inertia to the disturbance was initially higher in non‐clonal evergreen plants. Similarly, plant deciduousness provided the strongest predictive weight for post‐disturbance recovery. Nevertheless, resilience, as a standalone measure, was not predictable by any plant growth form or by inertia. Values of resilience based on multivariate ordinations suggested potential variation in hysteresis and homeostasis among groups. Quantification of resilience in both two‐dimensional and multivariate contexts represents a significant advancement in resilience ecology. Such methods may be broadly applicable to other ecosystems, provided a measure of pre‐disturbance conditions is available.