Arkansas Project: Risk assessment for Giant Salvinia in Arkansas waters

Arkansas Project

Risk assessment for Giant Salvinia in Arkansas waters

August 2022 - June 2023

Personnel

Participating Agencies

Arkansas Game & Fish Commission

Giant salvinia (Salvinia molesta) is the second worst aquatic weed in the world, and in North America, it causes millions of dollars in damages per year to agriculture, fishing industries, recreation, ecosystem health, and human health. Giant salvinia is spreading rapidly throughout the Southeastern United States, including in Arkansas, and climate change is likely to exacerbate the risk and rate of its spread. A preventative management approach that focuses on early detection and rapid eradication responses will be the most successful and cost effective. Thus, there is a critical need to develop a risk assessment tool that both facilitates early detection of giant salvinia and assesses the feasibility of rapid eradication. Here, our goal is to develop and implement a risk assessment tool that 1) facilitates early detection of giant salvinia by quantifying the likelihood of giant salvinia invasion in Arkansas under multiple potential future climate scenarios and 2) determines the feasibility of successfully eradicating giant salvinia in water bodies if giant salvinia is introduced. This risk assessment tool will help Arkansas Game & Fish Commission develop and improve preventative management strategies such as prioritizing monitoring efforts, developing rapid response plans tailored to specific water bodies, and targeted public outreach.

Research Publications

Research Publications	Publication Date
Roberts CP, Grant WE, Horton ML, LaBrie LAP, Peterson MR, Rogosch JS, Wang H. 2024. Balancing ecology and practicality to rank waterbodies for preventative invasive species management. Ecological Solutions and Evidence. \| Abstract	August 2024	1. Early detection and rapid response (EDRR) is the most successful framework for preventative invasive species management, but prioritizing localized EDRR actions with limited resources is challenging. An approach that ranks individual locations, such as waterbodies, for EDRR by combining an invasive species’ establishment risk with the practicality of managing it could help set reasonable priorities.<br>2. Here, we worked with regional practitioners in Arkansas, USA and the broader Southeastern USA to co-produce a workflow for preventative aquatic invasive species management that 1) estimates establishment risk under current and future climates with a species distribution model, 2) scores waterbodies according to difficulty of eradicating an aquatic invasive species if it were introduced, and 3) combines establishment risk and eradication difficulty scores to rank waterbodies according to preventative management priority. As our focal species, we used giant salvinia (<i>Salvinia molesta</i>), a floating aquatic fern ranked among the worst weeds in the world due to its negative socioecological impacts and difficulty to eradicate once established.<br>3. Current establishment risk is low for much of our study area, but under future climate scenarios (RCP 8.5), areas with > 60% giant salvinia establishment risk increased from 546 km<sup>2</sup> to 30,219 km<sup>2</sup> between 2023 and 2040 in Arkansas.<br>4. We found giant salvinia establishment risk and eradication difficulty are independent of each other (<i>r</i> = 0.28), and it follows that, alone, early detection tools such as species distribution models are insufficient for managers to prioritize sites for EDRR.<br>5. We envision our approach fitting into a potential EDRR workflow that cascades from broad- to local-scale. To illustrate, 1) horizon scanning and/or climate matching generates lists of high-risk invasive species; 2) species lists are narrowed according to eradication feasibility scores; 3) for all remaining species, all waterbodies across a geography of interest receive prioritization rankings based on establishment risk and eradication difficulty scores. Given that climate change makes predicting invasive species’ distributions a moving target, combining co-produced eradication difficulty scoring with species distribution modeling will balance rigor with practicality when prioritizing locations for EDRR.<br><br>
Roberts CP, Grant WE, Horton ML, LaBrie LAP, Peterson MR, Rogosch JS, Wang H. 2024. Balancing ecology and practicality to rank waterbodies for preventative invasive species management. Ecological Solutions and Evidence. \| Abstract	August 2024	1. Early detection and rapid response (EDRR) is the most successful framework for preventative invasive species management, but prioritizing localized EDRR actions with limited resources is challenging. An approach that ranks individual locations, such as waterbodies, for EDRR by combining an invasive species’ establishment risk with the practicality of managing it could help set reasonable priorities.<br>2. Here, we worked with regional practitioners in Arkansas, USA and the broader Southeastern USA to co-produce a workflow for preventative aquatic invasive species management that 1) estimates establishment risk under current and future climates with a species distribution model, 2) scores waterbodies according to difficulty of eradicating an aquatic invasive species if it were introduced, and 3) combines establishment risk and eradication difficulty scores to rank waterbodies according to preventative management priority. As our focal species, we used giant salvinia (<i>Salvinia molesta</i>), a floating aquatic fern ranked among the worst weeds in the world due to its negative socioecological impacts and difficulty to eradicate once established.<br>3. Current establishment risk is low for much of our study area, but under future climate scenarios (RCP 8.5), areas with > 60% giant salvinia establishment risk increased from 546 km<sup>2</sup> to 30,219 km<sup>2</sup> between 2023 and 2040 in Arkansas.<br>4. We found giant salvinia establishment risk and eradication difficulty are independent of each other (<i>r</i> = 0.28), and it follows that, alone, early detection tools such as species distribution models are insufficient for managers to prioritize sites for EDRR.<br>5. We envision our approach fitting into a potential EDRR workflow that cascades from broad- to local-scale. To illustrate, 1) horizon scanning and/or climate matching generates lists of high-risk invasive species; 2) species lists are narrowed according to eradication feasibility scores; 3) for all remaining species, all waterbodies across a geography of interest receive prioritization rankings based on establishment risk and eradication difficulty scores. Given that climate change makes predicting invasive species’ distributions a moving target, combining co-produced eradication difficulty scoring with species distribution modeling will balance rigor with practicality when prioritizing locations for EDRR.

Cooperative Fish and Wildlife Research Units Program: Arkansas Education, Research and Technical Assistance for Managing Our Natural Resources