Plan of the Invasive Species Management in Deepdene and Fernbank Parks

Countless native plant populations have been negatively impacted by the growing infestations of invasive species (Reichard and White, 2001). Additionally, it has been cited that invasive species cost the United States up to almost $120 billion per year in damages and losses (Pimentel, Zuniga & Morrison, 2005). The Southeast United States is home to myriad of these disruptive species including English Ivy, Chinese Privet, Kudzu, and many others.

Though management efforts have been put into place, they are often labor-intensive and costly. For example, it was found that stump cutting and herbicide application is the most effective removal method for Chinese Privet (Enloe et al., 2018). However, English Ivy is more effectively removed by hand pulling (Biggerstaff & Beck, 2007) and Kudzu is best removed through a leaf-cutting technique (Frye, Hough-Goldstein & Kidd, 2012). Management and control plans are vital; however, species-specific, trait-based risk assessments require increased accuracy to produce economic and environmental benefits to an ecosystem and community (Lodge et al., 2016).

Furthermore, these differing processes of invasive removal can result in unforeseen consequences to the ecosystem even when they are eradicated; substantially negative impacts include soil erosion, nutrient leaching, barren patches of soil, and more (Biggerstaff & Beck, 2007). Because of these risks, it is imperative that more research be done to compare the effects of invasive species removal methods both on their effectiveness and repercussions.

Deepdene Park and Fernbank are two parks in Atlanta, GA that are publically and privately owned, respectively. Both work through a contract basis with invasive species removal companies while also enlisting the help of the community in their restorative efforts. However, both parks have varied methods of removal. Deepdene has been working to reduce the entirety of invasive species throughout the whole park over a long period without species specific plans.

Conversely, Fernbank has worked on specific areas and species in hopes of complete eradication. It is our goal to compare these methodologies. It is imperative, however, that foot traffic, funding, full management protocols, time since last removal and additional confounding variables be taken into account.

Because both parks are so similar in their ecosystems, the data collected through our research will lead to opportune comparisons. The purpose of our study is to measure the effectiveness and side effects of these differing methods of removing common Georgia woodland invasive species. The goal of our research is to answer the following questions:

• Which invasive species management method is most effective in reducing the density of invasive Southeastern plants in comparing Deepedene Park and Fernbank?
• What factors impact the efficacy of these methods?
• Which invasive species removal methods pose the least risk to the ecosystem in the long term?

To test our research question, our ultimate objective is to identify the dominance of certain invasive species through percent composition of species in a plot and through visual inspection. We will create five 1m x 1m plots with flaggers and twine in both Deepdene Park and Fernbank in Atlanta, GA before park-planned daylong invasive species removal efforts are held. Both aforementioned parks have a creek running through them from East to West. These creeks will be used as a parameter guideline for where the plots will be placed; plots will run along the creek 25 m from the creek’s bank in upland areas with forest canopy cover.

The plots will be surveyed for tree cover, species and species count, growing substrate, and percent ground cover. Species counts will be conducted using stem counts and percent cover for ivy species and will be identified visually, using the iNaturalist app, and taking samples to experts if no identification can be confidently made. The plots will be surveyed once before the community removal days as a measure of species evenness. We will then analyze species richness by doing a 10 minute, total count effort with 2 people to identify plants that were not represented in our plots.

We will use the Shannon-Wiener index of Diversity to create a quantitative value of comparison. Considering the management methods between the two parks and the time since last removal efforts, we will analyze the methods of removal and corresponding effectiveness by creating percent composition charts of species present in each of the plots both pre- and post-removal.

It is expected that Fernbank, being a larger and more commercialized private park, will have a higher incentive to manage invasive species, a better or more regimented management plan, and thereby a reduced density of invasive species in comparison to Deepedene park. Their management methods are species-specific and it is thereby expected that their efforts will be more effective.