Suppression of reed canarygrass by assisted succession: A sixteen-year restoration experiment

Assisted succession could enable long-term restoration of invaded areas where successional trajectories have stalled due to competition from invasive species. Many invasives are shade-intolerant, therefore interventions that reduce light availability should suppress invasion and simultaneously re-establish successional processes. However, restoration success also depends on identifying critical system thresholds, e.g., invader abundances below which regeneration of desired species is possible. We report the successful use of assisted succession to restore a swamp forest invaded by Phalaris arundinacea (reed canarygrass; hereafter Phalaris), initiated by a high-density planting of woody species to outcompete the invader by reducing light availability.
We established five pre-planting treatments in a Phalaris near-monoculture in Wisconsin, USA: herbicide-only, herbicide+plow, herbicide+burn, herbicide+mow, and control. In 2003 we planted 23 tree and shrub species at high densities, then i...,
Study area and treatments: This study was conducted in southeastern Wisconsin, USA at the Huiras Lake State Natural Area (Lat: 43.5136095, Lon: -87.9828698). In 2002, 0.50 ha of a near-monoculture field of Phalaris was divided into 50 plots ranging from 30.3 to 154 m2. Except for two large blocks left as eight untreated control plots, the entire site was sprayed with 0.7% active ingredient glyphosate solution in early November 2002; such late-season herbicide application is recommended for Phalaris (Adams & Galatowitsch, 2006). Four pre-planting invader removal treatments were established in sprayed plots between fall 2002 and spring 2003 (Hovick & Reinartz, 2007): 1) herbicide-only (H) – no additional pre-planting treatment; 2) mow+herbicide (MH) – Phalaris biomass mowed in early fall 2002, before herbicide application; 3) herbicide+burn (HB) – herbicide application followed by burning Phalaris litter in spring 2003; and 4) herbicide+plow (HP) – herbicide application followed ..., , ## Palacio-Lopez K, Hovick SM, Mattingly KZ, Weston LM, Hofford NP, Finley L, Tayal A, Reinartz JA. Suppression of reed canarygrass by assisted succession: A sixteen-year restoration experiment. Journal of Applied Ecology.

[https://doi.org/10.5061/dryad.r7sqv9sks](https://doi.org/10.5061/dryad.r7sqv9sks)

## Summary

1. Assisted succession could enable long-term restoration where successional trajectories stall due to competition from invasive plants. Many invasives are shade-intolerant, therefore interventions reducing light availability should suppress invasion and re-establish successional processes. However, given how ubiquitous nonlinearities are in ecology, restoration success also depends on identifying critical system thresholds, e.g., invader abundances below which regeneration of desired species is possible. We report the successful use of assisted succession to restore a swamp forest invaded by Phalaris arundinacea (reed canarygrass; hereafter Phalaris), initiated by a high...