Milfoilmapper: a web-based tool built to aid in Eurasian watermilfoil management plans

Abstract

Invasive watermilfoil strains can differ in their growth, spread, impacts, and herbicide response. For example, strains of Eurasian (Myriophyllum spicatum L.) and hybrid (M. spicatum x M. sibiricum) watermilfoil have been characterized as resistant or susceptible to specific herbicides (e.g. fluridone and 2,4-D). Identifying resistant and susceptible strains can inform managers as to whether a specific herbicide should be used to treat a lake. However, prior to this work, there has been no centralized location where Eurasian and hybrid watermilfoil strain information is housed, which potentially restricts access to important information. To address this need, we built MilfoilMapper, a publicly available, user-friendly, R Shiny application that houses watermilfoil strain distribution and herbicide response information that is publicly available. To date, we have identified over 300 strains from over 290 lakes across the United States sent by state agencies, aquatic plant managers and citizen scientists. Although some strains have only been identified from a single lake, many strains have been found in multiple lakes. Therefore, strain information obtained from either the field or the lab can be applied to additional lakes where they are found. We encourage people to incorporate genetic surveying and monitoring into their Eurasian watermilfoil management plans to help identify strains to prioritize for herbicide characterization. We believe the creation of MilfoilMapper will facilitate these efforts by providing a centralized, interactive platform for tracking watermilfoil strain data, connecting lake managers, stakeholders, and state agencies to share experiences and resources to improve the efficacy and efficiency of invasive watermilfoil management.