Reestablishment best practices for Hymenocallis coronaria: a charismatic flowering macrophyte and indicator species for fall line stream restoration in the southeastern U.S.A.

Abstract

Charismatic indicator species, which are defined by their sensitivity to ecosystem degradation and attractive traits, are often reintroduced or monitored in restoration projects to evaluate whether desired ecosystem structure and function has been restored and to attract public support for restoration projects. Hymenocallis coronaria is a charismatic and imperiled aquatic plant endemic to southeast U.S. fall line streams. Known for its blooms and sensitivity to flow modification, it provides an opportunity to incorporate the reintroduction of a charismatic indicator species into stream restoration projects. The goal of our research was to provide restoration practitioners with experimentally derived H. coronaria reestablishment best practices by investigating the effects of life stage and outplanting technique on establishment success, with additional considerations given to treatment efficiency. We used binomial generalized linear models to analyze H. coronaria establishment from experimental reestablishment efforts in a free‐flowing segment of Stevens Creek, South Carolina. Model selection showed a strong interaction effect between life stage and outplanting technique and that technique is more important than life stage. Interpretation of our top model indicated that the wedge technique was the most successful and that wedging spring bulbs was significantly more successful than wedging other life stages. However, we recommend that practitioners wedge seedlings or broadcast seeds into existing shoal crevices because of efficiency. Our best practices reflect the need to align reestablishment efforts with H. coronaria's life history to maximize efficiency and suggest that H. coronaria has utility as an indicator species for restored flow regimes of southeast U.S. fall line streams.