Survival and Growth of Planted Uniola paniculata and Dune Building Using Surrogate Wrack on Perdido Key Florida, U.S.A.

Abstract

The increasing number of stresses on coastal dune ecosystems requires the use of more effective restoration strategies to enhance dune‐building and increase vegetation reestablishment. In this study, the use of a wheat straw as a surrogate wrack was an effective method to improve growth of spring planted Uniola paniculata (sea oats). Approximately 1,000 U. paniculata plugs were planted within 21 × 4 m plots at six replicate sites. Two weeks later, plantings were divided into 11 × 4 m subplots with half of the subplots receiving five bales of wheat straw and the remaining subplots receiving no wheat straw. This surrogate wrack layer measured approximately 10 cm in depth. Mean aboveground biomass of U. paniculata 6 months after planting with surrogate wrack was 9.25 ± 1.00 g compared with 2.18 ± 0.24 g without surrogate wrack. Number of tillers, tiller height, and basal width were also greater at the end of the first growing season for plants treated with surrogate wrack (p < 0.05). Two years after planting, significantly more inflorescences occurred and aboveground biomass (g/m2) was greater with than without surrogate wrack. Sand accumulation was notably greater with surrogate wrack (11.16 cm) than without wrack (7.78 cm) 8 months after planting (p = 0.1093). However, relative sand accumulation was significantly greater with than without surrogate wrack 2 years after planting. Increased sand accumulation suggests surrogate wrack either directly or indirectly traps more sand by creating an additional obstacle or promoting the growth of dune grasses.

Wrack enhancement of post-hurricane vegetation and geomorphological recovery in a coastal dune

“…Wrack enhanced the overall vegetation recovery and had particularly strong effects on several grass species, supporting previous studies’ findings on wrack effects on coastal dune plant communities [ 35 , 36 ]. Storm wrack likely boosted plant establishment and growth by provisioning limiting nutrients.…”

“…In summary, our results build on previous studies which have investigated the effects of small-scale wrack additions on undisturbed dunes [ 35 ], by showing novel direct experimental evidence that removal of storm wrack hinders vegetation development. In addition, we show that while not contributing to overall dune growth rate, wrack removal reduced overall elevation.…”

Wrack enhancement of post-hurricane vegetation and geomorphological recovery in a coastal dune

“…In summary, our results build on previous studies which have investigated the effects of small-scale wrack additions on undisturbed dunes (Hooton et al, 2014), by showing novel direct experimental evidence that removal of storm wrack hinders vegetation development.…”

Foredune‐forming grass and plant diversity show contrasting responses along the southeastern United States coast after hurricane disturbance

“…Considering the key role that this species has in driving dune growth, recovery and erosion resistance (Maun, 2009;Hooton et al, 2014;Feagin et al, 2019), our work highlights the need to further investigate the consequences that this latitudinal gradient might have on the dune resilience against increasing storm frequency and strength (Woodruff et al, 2013).…”