The Effect of Dune Age and Microtopography on Triadica sebifera (Chinese tallow tree) Recovery from Hurricane Disturbance
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Authors
Burruss, George
Issue Date
2022-05-08
Type
Thesis
Language
en_US
Keywords
University of the South , Biology Department , Senior Honor Theses 2022 , Chronosequence , Chinese tallow tree , hurricane disturbance , Coastal ecology , invasive species
Alternative Title
Abstract
The distribution and density of invasive species is a function of dispersal combined with the effects of disturbance. Disturbance is a necessary prerequisite for the colonization of most invasive species. Coastal dune communities experience a high frequency of disturbance, such as associated with hurricanes, making them susceptible to invasion by non-native species. Due to a rapid growth rate, high fecundity, stress tolerance, and persistent seed bank the non-native Triadica sebifera (Chinese tallow tree) is an aggressive invader of the southeastern coastal plain. We examined tallow population recovery after hurricane disturbances in 2017 as a function of three variables; microtopography (swale, slope, ridge), dune age (young, intermediate, old), and time since disturbance (pre-hurricane, post, and 4 years out). We investigated whether the initial tallow invasion on the island in the early 1990s had been facilitated by hurricane disturbance. We hypothesized that mechanisms of population persistence would vary as a function of microtopography and dune age. We predicted that adult survivorship would increase with dune age and would be restricted to slopes and ridges. We found that tallow, unlike most invasive species, had invaded without the facilitation of major disturbances. We found that after four growing seasons all tallow populations had recovered to pre-hurricane densities regardless of dune age. Adult survivorship was significantly higher in slopes and ridges as compared to swales. Population recovery in swales was almost exclusively a result of recruitment of new individuals from the buried seed pool despite the salt water inundation from the hurricanes. Our results show that tallow was able to successfully invade and establish populations across a barrier island dune chronosequence in the absence of a major disturbance event. Following a major hurricane, tallow was resilient to disturbance allowing it to persist and maintain pre-hurricane abundance.
Description
Citation
Publisher
University of the South